CN113838994A

Movatterモバイル変換

Info

Publication number: CN113838994A
Application number: CN202110930115.0A
Authority: CN
Inventors: 魏山山; 龙浩晖; 方建平
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2019-11-29
Filing date: 2019-11-29
Publication date: 2021-12-24
Anticipated expiration: 2039-11-29
Also published as: KR102684476B1; WO2021103979A1; JP7416940B2; CN113838994B; KR20220105665A; CN112885870A; JP2023503668A

Abstract

Translated fromChinese

本申请提供了一种显示面板、柔性显示屏和电子设备及显示面板的制备方法。显示面板包括基板、薄膜晶体管层、像素定义层、至少两个封装结构和至少两个像素单元，至少两个封装结构封装至少两个像素单元。基板、薄膜晶体管层及像素定义层叠置；像素定义层，具有像素区，及围绕封装结构封装的像素单元设置的侧封装区；像素单元的OLED发光器件设置于像素区；封装结构的第一封装层设置于OLED发光器件的靠近薄膜晶体管层的一侧；封装结构的第二封装层设置于OLED发光器件的远离薄膜晶体管层的一侧，其与第一封装层在侧封装区密封接触。设置至少两个封装结构对像素单元进行封装，可避免封装结构在弯折过程中开裂，起到水氧隔绝作用。

The present application provides a display panel, a flexible display screen, an electronic device, and a preparation method of the display panel. The display panel includes a substrate, a thin film transistor layer, a pixel definition layer, at least two encapsulation structures and at least two pixel units, and the at least two encapsulation structures encapsulate at least two pixel units. The substrate, the thin film transistor layer and the pixel definition layer are stacked; the pixel definition layer has a pixel area and a side encapsulation area arranged around the pixel unit encapsulated by the encapsulation structure; the OLED light-emitting device of the pixel unit is arranged in the pixel area; the first encapsulation of the encapsulation structure The layer is arranged on the side of the OLED light emitting device close to the thin film transistor layer; the second encapsulation layer of the encapsulation structure is arranged on the side of the OLED light emitting device away from the thin film transistor layer, and is in sealing contact with the first encapsulation layer in the side encapsulation area. Setting at least two encapsulation structures to encapsulate the pixel unit can prevent the encapsulation structures from cracking during the bending process, and play a role in isolating water and oxygen.

Description

Display panel, flexible display screen, electronic equipment and preparation method of display panel

Technical Field

The application relates to the technical field of display, in particular to a display panel, a flexible display screen, electronic equipment and a preparation method of the display panel.

Background

An organic light-emitting diode (OLED) display device has been classified as a next generation display technology with great development prospect due to its advantages of being thin, light, wide in viewing angle, active in light emission, continuously adjustable in light emission color, low in cost, fast in response speed, low in energy consumption, low in driving voltage, wide in working temperature range, simple in production process, high in light-emitting efficiency, capable of flexibly displaying, and the like.

The components such as moisture and oxygen in the air have a great influence on the lifetime of the OLED light emitting device in the OLED display device because: when the OLED light-emitting device works, electrons need to be injected from the cathode, the lower the work function of the cathode is, the better the work function of the cathode is, but the cathode is usually made of metal materials such as aluminum, magnesium, calcium and the like, has more active chemical properties and is very easy to react with water vapor and oxygen which permeate in. In addition, moisture and oxygen can chemically react with the hole transport layer and the electron transport layer of the OLED light emitting device, which can cause the OLED light emitting device to fail. Therefore, strict water and oxygen sealing packaging needs to be performed on the OLED light-emitting device, so that each functional layer of the OLED light-emitting device is sufficiently separated from components such as water vapor and oxygen in the atmosphere, the service life of the OLED light-emitting device is greatly prolonged, and the service life of the OLED display device is prolonged.

At present, when a display panel of an OLED display device is manufactured, a TFE (thin film encapsulation) technology is generally used for encapsulation. The display panel adopting TFE for whole-surface packaging is easy to generate cracks when being subjected to pressure or impact, so that water vapor and oxygen can enter a cathode (cathode material is MgAl generally) and other evaporation layers of an OLED light-emitting device along the cracks, the cathode loses an electrode function, in addition, the luminous efficiency of a luminous layer of the OLED light-emitting device is gradually reduced until the luminous device cannot emit light, the phenomenon of black spots or black spots is presented, and the display effect of the OLED display device is influenced.

Disclosure of Invention

The technical scheme provides a display panel, a flexible display screen, electronic equipment and a preparation method of the display panel, so as to improve the packaging characteristic of the display panel.

In a first aspect, the present application provides a display panel, which includes a substrate as a substrate, and a thin film transistor layer, a pixel definition layer, at least two package structures and at least two pixel units disposed on the substrate, where the at least two package structures are used for packaging the at least two pixel units. The thin film transistor layer is arranged on the substrate, the pixel definition layer is arranged on the thin film transistor layer and is provided with a pixel area and a side packaging area, the side packaging area is arranged around a pixel unit packaged by the packaging structure, and the pixel area and the side packaging area are through holes arranged on the pixel definition layer. A portion or all of the OLED light emitting device of the pixel unit may be disposed in the pixel region.

When the package structure is specifically arranged, the package structure comprises a first package layer and a second package layer. The first packaging layer is arranged on one side, close to the thin film transistor layer, of the OLED light-emitting device, and is exposed from the side packaging area; the second packaging layer is arranged on one side, far away from the thin film transistor layer, of the OLED light-emitting device and can pass through the side packaging area to be in sealing contact with the first packaging layer at the side packaging area. At least two pixel units are packaged by applying at least two packaging structures, so that a large packaging layer can be prevented from being formed on the display panel, and the problem that water and oxygen penetrate due to cracking of the packaging layer under the conditions of bending, curling, free deformation and the like of the flexible display screen comprising the display panel can be effectively solved.

In one possible embodiment of the present application, the number of the encapsulation structures may be the same as the number of the pixel units, and each encapsulation structure is used for encapsulating one pixel unit, so as to implement independent encapsulation of each pixel unit, which is beneficial to improving the bending property of the display panel.

In addition, the first encapsulation layer may be a single-layer structure formed by inorganic material layers, or a multi-layer structure formed by alternately stacking inorganic material layers and organic material layers; the second encapsulation layer may be, but not limited to, a single layer structure formed of inorganic material layers, or a multi-layer structure formed of inorganic material layers and organic material layers alternately stacked. Wherein, the inorganic material layer can be formed by silicon dioxide, silicon nitride or aluminum oxide and the like, so as to form better barrier effect on water and oxygen.

In one possible embodiment of the present application, the display panel may further include a metal line, and the metal line may be disposed on a side of the pixel defining layer away from the substrate; or the metal wire is arranged on the first packaging layer; or the metal wire is arranged on the layer structure of the substrate. The cathodes of the OLED light emitting devices may be connected to the metal lines to associate the OLED light emitting devices with each other, thereby facilitating control of display of the entire display panel.

In one possible embodiment of the present application, a support pillar is further disposed on a side of the pixel defining layer away from the substrate, and the support pillar can effectively prevent an evaporation mask plate used for forming each functional layer of the OLED light emitting device by evaporation from contacting the display panel in the process of forming the OLED light emitting device by evaporation, so as to improve the product yield of the display panel.

In one possible embodiment of the present application, a planarization layer may be further disposed on a side of the second encapsulation layer away from the thin-film transistor layer. Through setting up the planarization layer, can provide smooth machined surface for follow-up process, in addition, the planarization layer also can cover the foreign matter, avoids the foreign matter to pierce through other retes that set up on the planarization layer.

In addition, a third packaging layer can be arranged on the planarization layer, and the third packaging layer is of a whole surface structure capable of covering at least two packaging structures, so that the water and oxygen blocking packaging effect of the display panel is improved. The third encapsulation layer may be a single layer structure formed by inorganic material layers or a multi-layer structure formed by alternately stacking inorganic material layers and organic material layers.

In a second aspect, the present technical solution also provides a flexible display screen, which may include a protective cover plate, a polarizer, a touch panel, and the display panel according to the first aspect, wherein: the polaroid is fixed on the protective cover plate, and the touch panel is arranged between the polaroid and the display panel; or, the touch panel is fixed on the protective cover plate, and the polarizer is arranged between the touch panel and the display panel. In addition, a heat dissipation layer can be further arranged on one side of the display panel, which is far away from the touch panel, and a protective layer is arranged on the heat dissipation layer.

Because two at least pixel units of this flexible display screen's display panel are capsulated by two at least packaging structure, can avoid forming the massive encapsulated layer on display panel like this to can effectually avoid this flexible display screen under scenes such as buckling, curling, free deformation, the problem that the water oxygen that the encapsulated layer fracture leads to sees through, thereby improve flexible display screen's demonstration inefficacy problem.

In a third aspect, the present technical solution also provides an electronic device, which includes a middle frame, a rear shell, a printed circuit board, and the flexible display screen according to the second aspect, wherein: the middle frame is used for bearing the printed circuit board and the flexible display screen, and the printed circuit board and the flexible display screen are positioned on two sides of the middle frame; and the rear shell is positioned on one side of the printed circuit board, which is far away from the middle frame.

The utility model provides an electronic equipment's flexible display screen has better characteristic of buckling, and folding or the in-process of buckling at this flexible display screen, the risk of the encapsulation layer fracture of flexible display screen's display panel is less to can avoid water oxygen to see through the problem that electronic equipment's flexible display screen display became invalid that the encapsulation layer leads to.

In a fourth aspect, the present application further provides a method for manufacturing a display panel, where the display panel includes a substrate, a thin film transistor layer, a pixel defining layer, at least two package structures and at least two pixel units, the at least two package structures are used to package the at least two pixel units, each package structure includes a first package layer and a second package layer, each pixel unit includes an OLED light emitting device, and the method includes:

preparing a substrate;

forming a thin film transistor layer on the substrate, and forming a first through hole in the thin film transistor layer, wherein the first through hole extends to a drain electrode of the thin film transistor layer;

forming a whole first packaging structure layer on the thin film transistor layer, and patterning the whole first packaging structure layer into a plurality of independent first packaging layers;

forming a pixel defining layer, and carrying out patterning treatment on the pixel defining layer to form a pixel area and a side packaging area on each first packaging layer, wherein the side packaging area is used for exposing the first packaging layers;

forming an OLED light-emitting device in the pixel area, wherein the OLED light-emitting device is connected with the drain electrode through the first through hole;

and forming a whole second packaging structure layer corresponding to the thin film transistor layer on one side of the OLED light-emitting device far away from the thin film transistor layer, patterning the whole second packaging structure layer into a plurality of independent second packaging layers, and enabling the second packaging layers to be in sealing contact with the first packaging layers in side packaging areas.

In a possible implementation manner, the specific step of forming the first encapsulation layer includes: deposition of SiO on thin-film transistor layers₂SiNx or Al₂O₃Forming a full-face first package structure layer; and patterning the whole first packaging structure layer to obtain at least two first packaging layers, wherein the patterning comprises one or more of coating, exposing, developing, etching or stripping.

In one possible implementation, before forming the pixel defining layer, the method further includes: and forming an anode on the first packaging layer, wherein the anode is connected with the drain through a first through hole. Wherein the specific steps of forming the anode include: sequentially depositing ITO, Ag and ITO on the first packaging layer to form an anode material layer; and subjecting the anode material layer to patterning treatment to obtain the anode, wherein the patterning treatment comprises one or more of coating, exposing, developing, etching or stripping.

In addition, after the forming of the pixel defining layer and before the forming of the OLED light emitting device, the method may further include: support posts are formed on the pixel defining layer.

In one possible implementation manner, in order to associate the OLED light emitting devices with each other, so as to facilitate the display control of the entire display panel, a metal line may be further formed on the pixel defining layer, and the cathode of the OLED light emitting device is connected to the metal line. In addition, the metal lines may also be formed on the first encapsulation layer or on the layer structure of the thin-film transistor layer. The method for forming the metal wire comprises the following specific steps: after forming the pixel defining layer, sequentially depositing Ti, Al and Ti to form a metal layer; and subjecting the metal layer to patterning treatment to obtain the metal wire, wherein the patterning treatment comprises one or more of coating, exposing, developing, etching or stripping.

In a possible implementation manner, the specific step of forming the second encapsulation layer includes: depositing SiO on the pixel defining layer and the OLED light-emitting device₂SiNx or Al₂O₃To form a full-face second package structure layer; and patterning the whole second packaging structure layer to obtain at least two second packaging layers, wherein the patterning comprises one or more of coating, exposing, developing, etching or stripping.

After forming the second encapsulation layer, a planarization layer may also be formed on the second encapsulation layer to provide a planar surface for processing of subsequent layer structures. In addition, the planarization layer can also cover the foreign matters, so that the foreign matters are prevented from penetrating through other film layers arranged on the planarization layer.

In a possible implementation manner, the manufacturing method may further include forming a third encapsulation layer on the planarization layer, where the third encapsulation layer covers the plurality of encapsulation units. So as to form a whole surface packaging layer on the display panel, thereby improving the water and oxygen barrier effect of the display panel.

In a fifth aspect, the present technical solution further provides a display panel, where the display panel includes a substrate as a substrate, a thin film transistor layer, a pixel defining layer, at least two package structures, and at least two pixel units, and the at least two package structures may be used to package the at least two pixel units. Wherein, the thin film transistor layer is arranged on the substrate; the pixel definition layer is arranged on the thin film transistor layer and provided with a pixel area and a side packaging area, the side packaging area is arranged around a pixel unit packaged by the packaging structure, and the pixel area and the side packaging area are through holes arranged on the pixel definition layer. The pixel unit includes an OLED light emitting device, and a portion or the whole of the OLED light emitting device is disposed in the pixel region. The thin film transistor layer comprises an inorganic material layer, a through hole is formed in the position corresponding to the side packaging area, and the inorganic material layer is exposed through the through hole.

Because the thin-film transistor layer comprises the inorganic material layer, the inorganic material layer can play a good water and oxygen blocking effect, and therefore the inorganic material layer of the thin-film transistor layer can be used as a packaging layer for realizing pixel unit packaging.

When the packaging structure is specifically arranged, the packaging structure is arranged on one side of the OLED light-emitting device far away from the thin film transistor layer. The packaging structure can penetrate through the side packaging area and the through hole and is in sealing contact with the inorganic material layer exposed from the through hole of the thin film transistor layer in the side packaging area. In this application technical scheme, encapsulate two at least pixel unit through using two at least packaging structure, can avoid forming the massive encapsulation layer like this to can effectually avoid including this display panel's flexible display screen under scenes such as buckling, curling, free deformation, the problem that the water oxygen that the encapsulation layer fracture leads to sees through. In addition, the inorganic material layer of the thin film transistor layer is used as a packaging layer for packaging the packaging unit, so that the processing steps of the display panel can be effectively reduced, the bending performance of the display panel is improved, and the manufacturing difficulty and the manufacturing cost are reduced. In addition, in the embodiment of the application, the encapsulation structure can encapsulate one or more of structures such as a planarization layer, a source electrode, a drain electrode, an interlayer dielectric layer, an intermetallic dielectric layer and a gate electrode besides encapsulating the OLED light emitting device, so that the encapsulated structure is protected.

In addition, the encapsulation structure may be a single layer structure formed of inorganic material layers, or a multi-layer structure formed of inorganic material layers and organic material layers alternately stacked. Wherein, the inorganic material layer can be formed by silicon dioxide, silicon nitride or aluminum oxide and the like, so as to form better barrier effect on water and oxygen.

In one possible embodiment of the present application, the display panel may further include a metal line, and the metal line may be disposed on a side of the pixel defining layer away from the substrate; or the metal wire is arranged on the layer structure of the thin film transistor layer. The cathodes of the OLED light emitting devices may be connected to the metal lines to associate the OLED light emitting devices with each other, thereby facilitating control of display of the entire display panel.

In one possible embodiment of the present application, a planarization layer may be further disposed on a side of the package structure away from the thin-film transistor layer. Through setting up the planarization layer, can provide smooth machined surface for follow-up process, in addition, the planarization layer also can cover the foreign matter, avoids the foreign matter to pierce through other retes that set up on the planarization layer.

In a sixth aspect, the present technical solution further provides a flexible display screen, which may include a protective cover plate, a polarizer, a touch panel, and the display panel as described in the fifth aspect, wherein: the polaroid is fixed on the protective cover plate, and the touch panel is arranged between the polaroid and the display panel; or, the touch panel is fixed on the protective cover plate, and the polarizer is arranged between the touch panel and the display panel. In addition, a heat dissipation layer can be further arranged on one side of the display panel, which is far away from the touch panel, and a protective layer is arranged on the heat dissipation layer.

In a seventh aspect, the present technical solution also provides an electronic device, which includes a middle frame, a rear shell, a printed circuit board, and the flexible display screen as in the sixth aspect, wherein: the middle frame is used for bearing the printed circuit board and the flexible display screen, and the printed circuit board and the flexible display screen are positioned on two sides of the middle frame; and the rear shell is positioned on one side of the printed circuit board, which is far away from the middle frame.

In an eighth aspect, the present application further provides a method for manufacturing a display panel, where the display panel includes a substrate, a thin film transistor layer, a pixel defining layer, at least two package structures, and at least two pixel units, where the at least two package structures are used to package the at least two pixel units, and the pixel units include OLED light emitting devices, and the method includes:

preparing a substrate;

forming a second through hole in the thin film transistor layer, wherein the second through hole extends to the inorganic material layer of the thin film transistor layer;

forming a pixel definition layer, and carrying out patterning treatment on the pixel definition layer to form a pixel area and a side packaging area, wherein the side packaging area is used for exposing the inorganic material layer of the thin film transistor layer;

and forming a whole-surface packaging structure layer corresponding to the thin film transistor layer on one side of the OLED light-emitting device far away from the thin film transistor layer, patterning the whole-surface packaging structure layer into at least two independent packaging structures, and hermetically contacting the packaging structures with the inorganic material layer of the thin film transistor layer in a side packaging region.

In one possible implementation, before forming the pixel defining layer, the method further includes: and forming an anode on the first packaging layer, wherein the anode is connected with the drain through the first through hole. Wherein the specific steps of forming the anode include: sequentially depositing ITO, Ag and ITO on the first packaging layer to form an anode material layer; and subjecting the anode material layer to patterning treatment to obtain the anode, wherein the patterning treatment comprises one or more of coating, exposing, developing, etching or stripping.

In a possible implementation manner, the specific steps of forming the package structure include: depositing SiO on the pixel defining layer and the OLED light-emitting device₂SiNx or Al₂O₃To form a full-face package structure layer; and patterning the whole packaging structure layer to obtain at least two independent packaging structures, wherein the patterning process comprises one or more of coating, exposing, developing, etching or stripping.

After the formation of the encapsulation structure, a planarization layer may also be formed on the second encapsulation layer to provide a planar surface for processing of subsequent layer structures. In addition, the planarization layer can also cover the foreign matters, so that the foreign matters are prevented from penetrating through other film layers arranged on the planarization layer.

In a ninth aspect, the present application further provides a display panel, where the display panel includes a substrate as a substrate, a thin film transistor layer, a pixel defining layer, at least two package structures, and at least two pixel units, and the at least two package structures may be used to package the at least two pixel units. Wherein, the thin film transistor layer is arranged on the substrate; the pixel definition layer is arranged on the thin film transistor layer and provided with a pixel area and a side packaging area, the side packaging area is arranged around the pixel unit packaged by the packaging structure, and the pixel area and the side packaging area are through holes arranged on the pixel definition layer. The pixel unit includes an OLED light emitting device, and a portion or the whole of the OLED light emitting device is disposed in the pixel region. The substrate comprises an inorganic material layer, a through hole is formed in the position corresponding to the side packaging area, and the inorganic material layer is exposed through the through hole.

Since the inorganic material layer can have a good water and oxygen blocking effect, the inorganic material layer of the substrate can be used as a packaging layer for realizing packaging of the packaging unit.

When the packaging structure is specifically arranged, the packaging structure is arranged on one side of the OLED light-emitting device far away from the thin film transistor layer. The packaging structure can penetrate through the side packaging area and the through hole and is in sealing contact with the inorganic material layer exposed from the through hole of the substrate in the side packaging area.

In this application technical scheme, encapsulate two at least pixel unit through using two at least packaging structure, can avoid forming the massive encapsulation layer like this to can effectually avoid including this display panel's flexible display screen under scenes such as buckling, curling, free deformation, the problem that the water oxygen that the encapsulation layer fracture leads to sees through. In addition, the inorganic material layer of the substrate is used as a packaging layer for realizing packaging of the packaging unit, so that the processing steps of the display panel can be effectively reduced, the bending performance of the display panel is improved, and the manufacturing difficulty and the manufacturing cost are reduced. In addition, in the embodiment of the application, the encapsulation structure can encapsulate one or more of structures such as a planarization layer, a source electrode, a drain electrode, an interlayer dielectric layer, an intermetallic dielectric layer and a gate electrode besides encapsulating the OLED light emitting device, so that the encapsulated structure is protected.

Drawings

Fig. 1 is a schematic structural diagram of an electronic device according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of a flexible display screen provided in an embodiment of the present application;

FIG. 3 is a schematic structural diagram of a display panel according to an embodiment;

fig. 4 is a schematic structural diagram of a display panel according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of an OLED light-emitting device provided in an embodiment of the present application;

fig. 6 is a schematic structural diagram of a package structure according to an embodiment of the present application;

FIG. 7 is a sectional view taken along line A-A of FIG. 6;

FIG. 8 is a cross-sectional view taken along line B-B of FIG. 6;

FIG. 9 is a schematic structural diagram of an LTPS-TFT substrate according to an embodiment of the present disclosure;

fig. 10 is a top view of a display panel formed with a first encapsulation layer according to an embodiment of the present disclosure;

fig. 11 is a cross-sectional view of a display panel formed with a first encapsulation layer according to an embodiment of the present disclosure;

fig. 12 is a cross-sectional view of a display panel provided with an anode formed according to an embodiment of the present application;

fig. 13 is a cross-sectional view of a display panel formed with a pixel defining layer according to an embodiment of the present disclosure;

FIG. 14 is a schematic structural diagram of a third metal grid line coupled to a cathode according to an embodiment of the present disclosure;

FIG. 15 is a cross-sectional view C-C of FIG. 14;

FIG. 16 is a cross-sectional view taken along line D-D of FIG. 14;

fig. 17 is a cross-sectional view of a display panel formed with support pillars according to an embodiment of the present application;

fig. 18 is a cross-sectional view of a display panel formed with an OLED according to an embodiment of the present application;

fig. 19 is a cross-sectional view of a display panel with a second encapsulation layer formed thereon according to an embodiment of the disclosure;

fig. 20 is a cross-sectional view of a display panel with a second encapsulation layer formed thereon according to another embodiment of the present application;

fig. 21 is a cross-sectional view of a display panel provided in an embodiment of the present application with a second planarization layer formed thereon;

fig. 22 is a cross-sectional view of a display panel formed with a third encapsulation layer according to an embodiment of the present application;

fig. 23 is a schematic structural diagram of a display panel according to another embodiment of the present application.

Reference numerals:

101-a display screen; 102-middle frame; 103-rear shell; 104-PCB; 1041-component; 301-upper encapsulation layer;

3011-a first inorganic layer; 3012-a second inorganic layer; 3013-a flexible interlayer; 302-lower encapsulation layer; 201-protective cover plate;

202-a polarizer; 203-touch panel; 204-a display panel; 205-heat sink layer; 206-a protective layer; 401-a carrier layer;

3021. 402-an insulating layer; 403-a buffer layer; 404-an active layer; 405-a gate insulating layer; 406-an inter-metal dielectric layer;

407-metal capacitance; 408-interlayer dielectric layer; 409-a first planarizing layer; 4081. 4091-a via hole;

PI 1-first substrate material layer; PI 2-a second substrate material layer; g-grid; m1 — first metal grid lines;

m2 — second metal grid lines; m3-third metal grid lines; an S-source electrode; a D-drain electrode; 410-a first encapsulation layer;

411-anode; 412-pixel definition layer; 4121-pixel region; 4122-side encapsulation area; 413-support columns;

414-hole injection layer; 415-a hole transport layer; 416-a light emitting layer; 417-electron transport layer; 418-a cathode;

419-a light extraction layer; 420-a second encapsulation layer; 421-a second planarization layer; 422-a third encapsulation layer; 43-pixel cell.

Detailed Description

To facilitate understanding of the display panel provided in the embodiment of the present application, an application scenario of the display panel provided in the embodiment of the present application is first described below, where the display panel may be disposed in an electronic device such as a mobile phone, a tablet computer, a wearable device, and a Personal Digital Assistant (PDA). Referring to fig. 1, an electronic device may generally include adisplay screen 101, amiddle frame 102, arear case 103, and a printed circuit board (PCB 104), wherein themiddle frame 102 may be used to carry the printed circuit board and thedisplay screen 101, thedisplay screen 101 and the printed circuit board are located at two sides of themiddle frame 102, and therear case 103 is located at one side of the printed circuit board far from themiddle frame 102. In addition, the electronic device may further include acomponent 1041 disposed on thePCB 104, and thecomponent 1041 may be, but is not limited to, disposed on a side of thePCB 104 facing themiddle frame 102. The display panel that this application embodiment provided specifically sets up in electronic equipment's display screen, and this display screen can be flexible display screen or rigid display screen. The flexible display screen may be an OLED flexible display screen, or a quantum dot light emitting diode (QLED) flexible display screen. In the following embodiments of the present application, the display screen is an OLED flexible display screen, and the display screens in other forms are arranged in a similar manner.

Referring to fig. 2, the OLED flexible display panel according to the embodiment of the present disclosure may include, but is not limited to, aprotective cover plate 201, apolarizer 202, atouch panel 203, adisplay panel 204, aheat dissipation layer 205, and aprotective layer 206, where when the OLED flexible display panel is specifically disposed, referring to fig. 2, thepolarizer 202 is fixed to theprotective cover plate 201, and thetouch panel 203 is disposed between thepolarizer 202 and thedisplay panel 204; thetouch panel 203 may be fixed to theprotective cover 201, and then thepolarizer 202 may be disposed between thetouch panel 203 and thedisplay panel 204.

Theprotective cover 201 may be a transparent glass cover or a cover made of organic material such as polyimide, so as to reduce the influence on the display effect of the display screen while playing a role of protection; thepolarizer 202 may be a circular polarizer for preventing the anode from reflecting light; thetouch panel 203 may be provided separately or integrated with thedisplay panel 204. Theheat dissipation layer 205 may be a heat dissipation copper foil, and theprotection layer 206 may be protection foam. The layers of the flexible display may be bonded together by optically clear adhesive or non-clear pressure sensitive adhesive (not shown). Thedisplay panel 204 is provided with a plurality of pixel units (not shown), and the plurality of pixel units may have any shape, and the arrangement manner thereof is not limited in the present application. Because the components such as water vapor and oxygen in the air have a great influence on the service life of the OLED light emitting device of the pixel unit, the pixel unit of the display panel needs to be strictly sealed by water and oxygen to fully separate the functional layers of the OLED light emitting device from the components such as water vapor and oxygen in the air.

Referring to fig. 3, fig. 3 shows a display panel of a typical OLED flexible display. The display panel has anupper encapsulating layer 301 and alower encapsulating layer 302, in this embodiment the "upper" of the display panel refers to the side of the display panel which, in use, is closer to the user. Wherein theupper package layer 301 is a coverThe display panel has a unitary structure including a firstinorganic layer 3011, a secondinorganic layer 3012, and aflexible interlayer 3013 disposed between the firstinorganic layer 3011 and the secondinorganic layer 3012. The first and second

inorganic layers

3011 and 3012 may be SiO layers formed by Chemical Vapor Deposition (CVD)₂The layer or SiNx layer, theflexible interlayer 3013 may be a Polyimide (PI) type or cured polyester type polymer organic layer formed by Ink Jet Print (IJP) technology. SiO 2₂Or the SiNx layer is used for playing a main water-oxygen isolation role, and theflexible interlayer 3013 can play a certain water-oxygen buffering role so as to release stress, increase flexibility and reduce packaging failure caused by foreign matters. Theupper package layer 301 has a whole surface structure, and the structure is a rigid structure, and when the upper package layer is bent, the upper package layer is subjected to a large stress, and cracks are likely to occur. Thus, when the firstinorganic layer 3011 or the secondinorganic layer 3012 cracks, no matter whether the organic layer between the two inorganic layers cracks, water and oxygen can enter the OLED light-emitting device and the cathode layer of the pixel unit of the display panel, so that the OLED light-emitting device fails or the cathode loses electrical characteristics, and black spots appear on the OLED flexible display screen. In addition, since theupper encapsulation layer 301 adopts a full-surface structure, water and oxygen entering the display panel through a crack can diffuse between adjacent pixel units, thereby causing failure of a plurality of OLED light emitting devices or causing the cathodes thereof to lose electrical properties, and seriously causing display failure of the whole OLED flexible display screen.

In addition, thelower package layer 302 generally includes a first substratematerial layer PI 1 and a second substrate material layer PI 2 (the first substratematerial layer PI 1 and the second substratematerial layer PI 2 may be both polyimide-type polymer organic layers) in the substrate of the display panel, and anisolation layer 3021 located between the first substratematerial layer PI 1 and the second substratematerial layer PI 2, where theisolation layer 3021 is generally SiO 2₂Or a SiNx layer. Thelower encapsulant layer 302 is a solid structure, and is also a solid structure that is also susceptible to cracking under bending. If thelower encapsulation layer 302 cracks, water and oxygen can enter the OLED light-emitting device along the cracks, so that the OLED flexible display screen has black spots. In additionIn addition, because thelower encapsulation layer 302 adopts a full-face structure, water and oxygen entering the display panel through a crack can be diffused between adjacent pixel units, so that a plurality of OLED light-emitting devices can fail or cathodes of the OLED light-emitting devices can lose electrical characteristics, and the display of the whole OLED flexible display screen can fail seriously.

Therefore, in the action processes of bending or folding the OLED flexible display screen and the like, water and oxygen enter from the cracks to cause the OLED light-emitting device to be corroded, so that the OLED light-emitting device is not electrified or is deteriorated, and further the OLED light-emitting device cannot emit light.

In order to solve the above problem, an embodiment of the present application provides a display panel to solve the problem that water and oxygen permeate through the display panel due to cracking of an encapsulating layer under the scenes of bending, curling, free deformation and the like, and can improve the failure problems such as black spots of a flexible display screen. The structure of the display panel will be described in detail with reference to the accompanying drawings.

Referring to fig. 4, an embodiment of the present application provides a display panel including a substrate, a thin-film transistor layer, apixel defining layer 412, a pixel unit, and an encapsulation structure. The thin film transistor layer is arranged on the substrate, and the pixel definition layer is arranged on the thin film transistor layer. As shown in fig. 4, in the embodiment of the present application, the substrate may provide a flexible carrier substrate for each stacked layer of thin film transistor layers and the like thereon, which may include, but is not limited to, a first substratematerial layer PI 1, anisolation layer 402, and a second substratematerial layer PI 2 stacked in sequence from bottom to top (in this embodiment, the "top" of the display panel refers to the side of the display panel close to the user when in use). Specifically, the material of the first substratematerial layer PI 1 may be a flexible polyimide substrate material, and may also be a flexible material such as polyethylene terephthalate (PET), paper, metal, and ultra-thin peeling; barrier layer 402(barrier), which may be used to block water and oxygen; the second substratematerial layer PI 2 may also be made of a flexible polyimide substrate material, and may also be made of a flexible material such as polyethylene terephthalate (PET), paper, metal, or ultra-thin glass. In some embodiments of the present disclosure, theisolation layer 402 or the second substratematerial layer PI 2 in the substrate may be omitted to simplify the structure of the substrate.

When the thin film transistor layer is specifically disposed, it may include one or more of thebuffer layer 403, the active layer, thegate insulating layer 405, the gate electrode G, the first metal grid line M1, the inter-metaldielectric layer 406, themetal capacitor 407, theinterlayer dielectric layer 408, the source electrode S, the drain electrode D, the second metal grid line M2, and thefirst planarization layer 409, which is not limited in this embodiment.

Optionally, in the embodiment of the present application, taking a Low Temperature Polysilicon (LTPS) Thin Film Transistor (TFT) as an example, the thin film transistor layer may include agate insulating layer 405, an inter-metaldielectric layer 406, aninterlayer dielectric layer 408, and afirst planarization layer 409. Optionally, the thin film transistor layer may include abuffer layer 403, agate insulating layer 405, an inter-metaldielectric layer 406, aninterlayer dielectric layer 408, and afirst planarization layer 409. Optionally, the thin film transistor layer may include abuffer layer 403, an active layer, agate insulating layer 405, a gate electrode G, an inter-metaldielectric layer 406, aninterlayer dielectric layer 408, a source electrode S, a drain electrode D, and afirst planarization layer 409. In the embodiment of the present application, the thin film transistor layer includes abuffer layer 403, an active layer, agate insulating layer 405, a gate G, a first metal grid line M1, an inter-metaldielectric layer 406, ametal capacitor 407, aninterlayer dielectric layer 408, a source S, a drain D, a second metal grid line M2, and afirst planarization layer 409, which is shown in fig. 4. The following describes the structure of each layer of the thin film transistor layer in the embodiment of the present application in detail:

the buffer layer 403(buffer) may be used to prevent the impurity ions from affecting the characteristics of the thin film transistor layer disposed on the substrate, and also has a water-oxygen barrier effect.

And an active layer mainly formed of P-Si and LTPS, the active layer being a semiconductor layer of the TFT, and a semiconductor switch and a conductive line may be formed according to doping, wherein, referring to fig. 4, the P-Si in the middle of the active layer is used to represent the semiconductor switch, and two portions of both sides of the P-Si are conductors to serve as a source S and a drain D connected to the P-Si.

A gate insulating layer 405(gate insulator) which may function to insulate and isolate the active layer from the gate electrode G.

A gate (gate) G formed on thegate insulating layer 405 and used as a TFT device switch, for example, for a P-type TFT, when a negative voltage is applied to the gate, a large current exists in the source and drain, the TFT is in an on state, when a positive voltage is applied to the gate, only a weak leakage current exists in the source and drain, and the TFT is in an off state; for an N-type TFT, when a negative voltage is applied to a grid electrode, only weak leakage current exists in a source electrode and a drain electrode, the TFT is in an off state, and when a positive voltage is applied to the grid electrode, larger current exists in the source electrode and the drain electrode, and the TFT is in an on state.

The first metal grid lines M1 are formed on thegate insulating layer 405 and may be formed simultaneously with the gate electrode G, often as scan lines. Since the screen display is a progressive scan display, the scan line turns on the gate of the TFT switch of each row, which acts to turn on the TFT gate switch of the row line by line, allowing the data line signal and the power line signal to refresh the row information.

An inter-metal dielectric (IMD)layer 406 may be used as an insulating layer between the first metal grid line M1 and the metal capacitor 407 (MC) and a dielectric layer of themetal capacitor 407.

Themetal capacitor 407, as the capacitor top electrode plate and other driving circuits, the first metal grid line M1 can also be used as the capacitor bottom electrode plate.

An interlayer dielectric layer 408 (ILD) serves as an insulating layer between the source and drain electrodes and the gate electrode G.

And a source electrode (source) S formed on theinterlayer dielectric layer 408 and connected to the active layer, wherein ohmic contact is formed after the source electrode S and the active layer are connected to realize circuit connection.

And a drain (drain) D formed on theinterlayer dielectric layer 408 and connected to the active layer, wherein the drain D and the active layer form ohmic contact after being connected to realize circuit connection.

The second metal grid line M2 is connected to themetal capacitor 407 through the via 4081 on theinterlayer dielectric layer 408, and theinterlayer dielectric layer 408 may be used as an insulating layer between the M2 and themetal capacitor 407; in addition, the second metal grid lines M2 may also be formed simultaneously with the source and drain electrodes S and D and serve as driving lines for the source and drain electrodes S and D to transmit data signals, power signals, and the like. Specifically, the data signal and the power signal are supplied via an Integrated Circuit (IC), and are generally transmitted through the second metal grid line M2. The row and column transport is performed in a transport direction generally perpendicular to the scan line direction. Each column of pixels has an independent data line which is inserted into the source S or the drain D of the TFT of the column for transmission. The power supply signal is also connected to the source S or the drain D of each row of TFTs for transmission, but unlike the data lines, the power supply signal is a simpler dc signal or a fixed-value pulse signal, so all power lines are generally connected in a short circuit for uniform transmission.

The first planarization layer 409 (PLN) serves to planarize, insulate, and protect the substrate electrode from undulations.

In the specific arrangement of thepixel defining layer 412, thepixel defining layer 412 may be a layer structure formed by coating a photoresist type organic material on the thin film transistor layer by means of slit coating. In addition, thepixel region 4121 and theside packaging region 4122 may be formed on thepixel defining layer 412 by exposing and developing, wherein thepixel region 4121 and theside packaging region 4122 may be formed as a hole structure penetrating through thepixel defining layer 412, and theside packaging region 4122 is disposed around the pixel unit packaged by the packaging structure.

The pixel unit is a minimum unit for implementing a display function of the display panel, and includes an OLED light emitting device, which may be disposed in the pixel region. Referring to fig. 5, fig. 5 shows a layer structure schematic diagram of an OLED light emitting device according to an embodiment of the present application. The OLED light emitting device may include, but is not limited to, an anode 411(anode), a hole injection layer 414 (HIL), a hole transport layer 415 (HTL), a light emitting layer 416 (EL), an electron transport layer 417 (ETL), a cathode 418(cathode), and a light extraction layer 419 (CPL) which are sequentially stacked. Referring to fig. 4 and 5 together, it can be understood that, in the process of manufacturing each layer structure forming the OLED light emitting device, since the material for forming each layer structure has fluidity, in order to reduce the control difficulty of the manufacturing process, a part of the material may spread outside thepixel region 4121, but it does not affect the light emitting effect of the OLED light emitting device. In the embodiments of the present application, the OLED light emitting device is partially disposed in the pixel region, and all the OLED light emitting devices may be disposed in the pixel region, which is not limited in the embodiments of the present application.

When the package structures are specifically arranged, the package structures may be arranged in a one-to-one correspondence with the pixel units, for example, each pixel unit is packaged by one package structure. Specifically, the encapsulation structure includes afirst encapsulation layer 410 and asecond encapsulation layer 420, and thefirst encapsulation layer 410 is disposed between the OLED light emitting device and the thin film transistor layer and can be exposed from theside encapsulation region 4122 of thepixel defining layer 412. As can be seen in fig. 4, thesecond encapsulation layer 420 covers the pixel unit, and thesecond encapsulation layer 420 is in sealing contact with thefirst encapsulation layer 410 through theside encapsulation region 4122. Therefore, each pixel unit is coated by thefirst packaging layer 410 and thesecond packaging layer 420, and each pixel unit is independently packaged. In addition, thepixel definition layer 412 is formed between two adjacent packaging structures, and thepixel definition layer 412 is made of an organic material and is a flexible material, so that the adjacent packaging structures can be flexibly connected. In this embodiment, thefirst encapsulation layer 410 may be, but is not limited to being, made of SiO₂SiNx or Al₂O₃Thesecond encapsulation layer 420 may also be made of, but not limited to, SiO, etc. inorganic materials₂SiNx or Al₂O₃And the like to play a better water-oxygen isolation role. It is understood that thefirst encapsulation layer 410 and thesecond encapsulation layer 420 may be a single inorganic encapsulation layer, or may be an encapsulation layer having a multi-layer stacked structure in which inorganic layers and organic layers are stacked, for example, a three-layer structure of inorganic layers-organic layers-inorganic layers, or a four-layer structure of inorganic layers-organic layers-inorganic layers-organic layersThe layer structure may be a five-layer or more structure stacked on top of each other.

By independently packaging each pixel unit by a packaging structure, a large packaging layer formed on the display panel can be avoided, and the packaging structures are independent from each other. When the display panel is applied to the OLED flexible display screen, the OLED flexible display screen is bent for more than 10 ten thousand times in any direction, and the display panel still has good packaging characteristics. Therefore, by adopting the display panel provided by the embodiment of the application, the risk of cracking of the packaging layer of the OLED flexible display screen under the application scenes of folding, curling, free deformation and the like can be reduced, so that the problem that water and oxygen penetrate through the packaging layer to enter the display panel to cause display failure of the display panel can be avoided. In addition, each pixel unit is independently packaged, and water and oxygen entering any packaging structure can be prevented from diffusing between adjacent OLED light-emitting devices, so that the light-emitting performance of the adjacent OLED light-emitting devices is prevented from being influenced.

In addition, it is worth mentioning that a plurality of pixel units (the number of the pixel units is less than the total number of the pixel units of the display panel) can be packaged by the same packaging structure. Referring to fig. 6, for example, for a display panel having a fixed single folding direction (the curve with an arrow in the figure indicates the folding direction), the pixel units may be packaged by grouping all the pixel units in a column or row manner along the folding direction to form a column or row packaging structure. Thereby effectively improving the folding performance of the display panel in a fixed single folding direction. In addition, compared with the embodiment of independently packaging each pixel unit, the pixel units are packaged by forming a row-shaped or row-shaped packaging structure, so that the manufacturing difficulty and the manufacturing cost can be effectively reduced. With reference to fig. 6, in other embodiments of the present application, several adjacent pixel units may be further packaged by using a packaging structure (see the dashed-dotted rectangle), and generally, the number of pixel units on the display panel is large, and the area of the packaging structure for packaging several adjacent pixel units is relatively small compared to the whole display panel. Since each pixel unit is independently packaged, or the pixel units of a plurality of pixel units, the number of which is less than the total number of the pixel units of the display panel, are packaged by the same packaging structure, which is discussed with respect to the pixel units of the display panel, both of the above two packaging structures are referred to as pixel-level packaging structures in the present application.

In order to electrically connect the OLED light emitting devices of the display panel encapsulated by the pixel level encapsulation structures, so as to control the display of the whole display panel, metal wires may be further disposed in the display panel. When the metal line is specifically arranged, it may be the third metal grid line M3 in fig. 4, and in conjunction with fig. 6, thecathodes 418 of the OLED light emitting devices of the respective pixel units are respectively connected with the third metal grid line M3, so that, referring to fig. 5, holes may sequentially pass through thehole injection layer 414 and thehole transport layer 415 of each OLED light emitting device through theanode 411 to reach thelight emitting layer 416. Electrons can pass from thecathode 418 through theelectron transport layer 417 to thelight emitting layer 416. The holes and the electrons are recombined with each other in thelight emitting layer 416 to form excitons in an excited state, the excitons transfer energy to the organic light emitting molecules of thelight emitting layer 416, and the electrons exciting the organic light emitting molecules transition from a ground state to an excited state. The excited state electrons are inactivated by radiation to generate photons to emit light. Since thecathodes 418 of each OLED light emitting device are connected by the third metal grid line M3, the third metal grid line M3 can transmit the cathode driving signal to thecathodes 418 of all OLED light emitting devices at the same time, so as to implement cathode signal synchronous control. The material of the third metal grid lines M3 may be titanium-aluminum alloy or molybdenum. In addition, when the third metal grid line M3 is specifically disposed, with reference to fig. 4, the third metal grid line M3 is disposed on a side of thepixel defining layer 412 away from the thin-film transistor layer; alternatively, referring to fig. 7 and 8, fig. 7 is a sectional view taken along line a-a of fig. 6, which is a sectional view of the display panel at a position where the third metal grid line M3 and thecathode 418 do not have an interconnection relationship; fig. 8 is a cross-sectional view B-B of fig. 6, which is a cross-sectional view of the display panel at a position where the third metal grid lines M3 and thecathode 418 have an interconnection relationship, and in the embodiment shown in fig. 7 and 8, the third metal grid lines M3 may be disposed on thefirst encapsulation layer 410. In addition, in other embodiments, third metal grid line M3 may also be disposed on the stacked structure of thin-film transistor layers (e.g.,planarization layer 409,interlayer dielectric layer 408, or inter-metal dielectric layer 406).

With continued reference to fig. 8, the display panel of the embodiment of the present disclosure may further include a supportingpillar 413 disposed on thepixel defining layer 412, where the supportingpillar 413 may be a photoresist type supporting pillar. By arranging the supportingcolumns 413 on thepixel defining layer 412, in the process of forming the OLED light-emitting device by evaporation, an evaporation mask plate for forming each functional layer of the OLED light-emitting device by evaporation is effectively prevented from contacting the display panel, so that the product yield of the display panel is improved.

In addition to the above structure, the display panel may further include asecond planarization layer 421, where thesecond planarization layer 421 is disposed on a side of thesecond encapsulation layer 420 away from the thin-film transistor layer. By providing thesecond planarizing layer 421, a smooth processing surface can be provided for the subsequent processes. In addition, thesecond planarization layer 421 may cover the foreign substance to prevent the foreign substance from penetrating through another film layer disposed on thesecond planarization layer 421. Further, with continued reference to fig. 8, a full-surfacethird encapsulation layer 422 may be further provided on thesecond planarization layer 421, and the full-surface encapsulation structure provided on the display panel is referred to as a panel-level encapsulation structure in this application. Therefore, the display panel is provided with the pixel level packaging structure and the panel level packaging structure at the same time, so that the water and oxygen blocking effect of the display panel is improved. Thethird encapsulation layer 422 may be a single inorganic encapsulation layer, or may be an encapsulation layer having a multilayer stack structure in which inorganic layers and organic layers are stacked one on another, for example, a three-layer structure of inorganic layers-organic layers-inorganic layers stacked in this order, a four-layer structure of inorganic layers-organic layers-inorganic layers-organic layers stacked in this order, or a five-layer or more structure stacked in this order.

In the display panel of the embodiment of the present application, a pixel-level package structure and a panel-level package structure are simultaneously disposed to form a dual protection for the pixel unit. At this time, even if water and oxygen enter the display panel through the panel-level packaging structure, the water and oxygen cannot enter the OLED light-emitting device under the blocking effect of the pixel electrode packaging structure. Therefore, the scheme can be favorable for improving the water oxygen blocking effect of the display panel.

The embodiment of the application further provides a flexible display screen, and the flexible display screen can include but is not limited to a protective cover plate, a polarizer, a touch panel, a display panel, a heat dissipation layer and a protective layer. When the flexible display screen is specifically arranged, the polaroid is fixed on the protective cover plate, and the touch panel is arranged between the polaroid and the display panel; the touch panel can also be fixed on the protective cover plate, and then the polarizer is arranged between the touch panel and the display panel. The display panel may adopt any one of the display panels in all the embodiments described above.

The protective cover plate can be a transparent glass cover plate or a cover plate made of organic materials such as polyimide and the like, so that the influence on the display effect of the display screen is reduced while the protective cover plate plays a role in protection; the polaroid can be a circular polaroid and is used for avoiding anode reflection light; the touch panel can be arranged independently or integrated with the display panel into a whole. The heat dissipation layer can select the heat dissipation copper foil for use, and the protective layer can be for protecting the bubble cotton. The various layer structures of the flexible display screen can be bonded through optically transparent adhesive or non-transparent pressure-sensitive adhesive.

When the display panel is specifically arranged, the display panel comprises a substrate, a thin film transistor layer, a pixel definition layer, at least two packaging structures and at least two pixel units, wherein the at least two packaging structures are used for packaging the at least two pixel units. The thin film transistor layer is arranged on the substrate, and the pixel definition layer is arranged on the thin film transistor layer. In the embodiment of the present invention, the substrate may provide a flexible carrier substrate for each stacked layer, such as a thin film transistor layer, above the substrate, which may include, but is not limited to, a first substrate material layer, an isolation layer, and a second substrate material layer stacked in sequence from bottom to top. In some embodiments of the present disclosure, an insulating layer or a second substrate material layer in the substrate may be omitted to simplify the structure of the substrate.

When the thin film transistor layer is specifically disposed, the thin film transistor layer may include one or more layers of a buffer layer, an active layer, a gate insulating layer, a gate, a first metal grid line, an inter-metal dielectric layer, a metal capacitor, an interlayer dielectric layer, a source, a drain, a second metal grid line, and a first planarization layer, which is not limited in the embodiment of the present application.

When the pixel definition layer is specifically arranged, the pixel definition layer is provided with a pixel area and a side packaging area, wherein the pixel area and the side packaging area can be hole structures penetrating through the pixel definition layer, and the side packaging area is arranged around a pixel unit packaged by the packaging structure. The pixel unit is a minimum unit for realizing a display function of the display panel, and includes an OLED light emitting device, and a part or all of the OLED light emitting device is disposed in the pixel region.

When the package structures are specifically arranged, the package structures may be arranged in a one-to-one correspondence with the pixel units, for example, each pixel unit is packaged by one package structure. Specifically, the packaging structure comprises a first packaging layer and a second packaging layer, wherein the first packaging layer is arranged between the OLED light-emitting device and the thin film transistor layer and can be exposed from the side packaging area of the pixel definition layer. The second packaging layer covers the pixel unit, penetrates through the side packaging area and is in sealing contact with the first packaging layer. Therefore, each pixel unit is coated by the first packaging layer and the second packaging layer, and independent packaging of each pixel unit is realized.

In one possible embodiment, a plurality of pixel units (the number of the plurality of pixel units is less than the total number of the pixel units of the display panel) can be packaged by the same packaging structure. For example, for a display panel with a fixed single folding direction, all pixel units may be grouped in a column or row along the folding direction to form a column or row packaging structure to package the pixel units.

The flexible display screen of the embodiment can be bent for more than 10 ten thousand times in any direction, and the display panel still has good packaging characteristics. Therefore, the flexible display screen can avoid the problem that water and oxygen penetrate due to cracking of the packaging layer under the application scenes of folding, curling, free deformation and the like, so that the problem that the water and oxygen penetrate through the packaging layer to enter the display panel and cause display failure of the display panel can be avoided. In addition, each pixel unit is independently packaged or packaged in groups, and water and oxygen entering any packaging structure can be prevented from diffusing between adjacent packaging structures, so that the light-emitting failure of the whole flexible display screen is avoided.

The embodiment of the present application further provides an electronic device, which includes a middle frame, a rear shell, a printed circuit board, and any of the flexible display screens in the foregoing all embodiments. The middle frame can be used for bearing a printed circuit board and an OLED flexible display screen, the OLED flexible display screen and the printed circuit board are located on two sides of the middle frame, and the rear shell is located on one side, far away from the middle frame, of the printed circuit board.

The electronic equipment of this application embodiment can be collapsible equipment, because this electronic equipment's OLED flexible display screen is at the folding in-process, and the risk of its display panel's encapsulated layer fracture is lower, consequently can avoid water oxygen to permeate through the encapsulated layer and get into display panel, leads to OLED flexible display screen to show the problem of inefficacy.

In order to further understand the structure of the display panel of the present application, an embodiment of the present application further provides a manufacturing process of the display panel. The detailed steps of the manufacturing process are as follows:

step 001: and manufacturing a substrate. In the embodiment of the present application, a top gate Low Temperature Poly Silicon (LTPS) Thin Film Transistor (TFT) substrate may be taken as an example, and a layer structure of the substrate may be set as shown in fig. 9, where the substrate may be formed on acarrier layer 401, and the carrier layer may be a carrier glass layer to play a role of carrying in a manufacturing process of a display panel; in addition, a viahole 4091 needs to be reserved on thefirst planarization layer 409 for subsequent electrode connection. As the manufacturing process of the LTPS-TFT substrate is mature, the manufacturing process of the LTPS-TFT substrate is not repeated in the application.

Step 002: afirst encapsulation layer 410 is fabricated. In this step, can be passedChemical Vapor Deposition (CVD) or Atomic Layer Deposition (ALD) methods for forming SiO₂SiNx or Al₂O₃The layer is deposited as afirst encapsulation layer 410. Then, through the processes of coating photoresist, exposing, developing, etching, stripping the photoresist, and the like, thefirst encapsulation layer 410 is subjected to patterning processing so as to correspond to each region for forming a pixel unit, and thefirst encapsulation layer 410 is broken through etching, so that an independentfirst encapsulation layer 410 is formed corresponding to each pixel unit. The pattern of thefirst encapsulation layer 410 formed by step 002 can be seen with reference to fig. 10, wherein the dashed lines indicate the areas for forming thepixel cells 43 and the solid lines indicate the individual first encapsulation layers 410 formed. Referring to fig. 11, fig. 11 is a cross-sectional view of the display panel after thefirst encapsulation layer 410 is manufactured, and it can be seen from the cross-sectional view that the viahole 4091 reserved on thefirst planarization layer 409 is kept away by the independentfirst encapsulation layer 410 formed corresponding to each pixel unit for the subsequent electrode connection.

Step 003: ananode 411 is fabricated. Generally, theanode 411 of the light emitting device of the OLED can be fabricated by sequentially depositing Indium Tin Oxide (ITO), Ag, and ITO by Physical Vapor Deposition (PVD). Then, theanode 411 may be patterned by coating a photoresist, exposing, developing, etching, stripping the photoresist, and the like to form theanode 411 as shown in fig. 12. Wherein theanode 411 can be in contact connection with the drain D through the via 4091 for sealing.

Step 004: a pixel definition layer 412 (PDL) is produced. First, a photoresist type organic material may be coated on thefirst planarization layer 409, thefirst encapsulation layer 410, theanode 411, and the like formed after the step 003 by using a Slit Coating (Slit Coating) method. Then, the patternedpixel defining layer 412 is obtained through the steps of exposure, development, and the like. As shown in fig. 13, in which apixel region 4121 is formed on the patternedpixel defining layer 412, and aside encapsulation region 4122 is formed around thepixel region 4121, the OLED light emitting device of the pixel unit may be formed on thepixel region 4121, and theside encapsulation region 4122 is used to expose thefirst encapsulation layer 410 for facilitating the subsequent encapsulation of the pixel unit.

Step 005: a third metal grid line M3 interconnected with the cathode is fabricated to subsequently electrically connect the cathodes of the OLED light emitting devices of the respective pixel cells. In addition, a part of the third metal mesh lines M3 may also be used as data lines for transferring data signals.

In general, when the third metal grid lines M3 are formed, first, materials such as Ti, Al, and Ti, or Mo may be deposited in sequence using PVD to form a metal layer on thepixel defining layer 412. Then, the metal layer may be patterned to form the third metal gridlines M3 through one or more of coating photoresist, exposing, developing, etching, and stripping photoresist, and illustratively, through the steps of coating photoresist, exposing, developing, etching, and stripping photoresist. Referring to FIG. 14, FIG. 14 illustrates one routing scheme for the third metal grid lines M3 (which includes the third metal grid lines M3 and the subsequently formed pattern of cathodes 418).

Referring to fig. 15, fig. 15 is a cross-sectional view taken along line C-C of fig. 14. FIG. 15 shows a cross-sectional view of the display panel after step 005 where the third metal grid lines M3 and thecathode 418 do not have an interconnecting relationship; fig. 16 is a cross-sectional view taken along line D-D in fig. 14, and fig. 16 shows a cross-sectional view of the display panel at a position where the third metal grid lines M3 and thecathode 418 have an interconnected relationship after step 005.

In one possible embodiment of the present application, after step 005, the fabrication process may further optionally include step 006: support posts 413 (PS) are fabricated. In forming the supportingpillars 413, a photoresist is typically coated by a slit coating process; then, the resisttype supporting posts 413 are obtained by exposure, development, or the like. The stacking relationship between the formed photoresist-type supporting posts 413 and thepixel defining layer 412 can be seen with reference to fig. 17. As shown in fig. 17, the cross-sectional shape of the photoresist-type supporting column 413 may be a trapezoid, but may also be other possible shapes such as a rectangle. The position of the photoresist-type support column 413 may be selected according to the specific situation. By manufacturing the supportingposts 413 on thepixel defining layer 412, it is effectively avoided that a mask plate contacts the surface of the display panel in the subsequent evaporation process of forming the OLED light emitting device.

Step 007: and manufacturing a patterned OLED light-emitting device. The OLED light emitting device includes, but is not limited to, a hole injection layer 414 (HIL), a hole transport layer 415 (HTL), a light emitting layer 416 (EL), an electron transport layer 417 (ETL), a cathode 418(cathode), and a light extraction layer 419 (CPL) which are sequentially stacked.

With reference to fig. 17 and 18, when forming the OLED light emitting device in thepixel region 4121 defined by thepixel defining layer 412, patterning of each layer structure of the OLED light emitting device is generally achieved by using a high-precision metal mask (FFM) evaporation process, a printing process, a film lift off (film lift off) process, a laser etching process, and a thickness step difference and a chamfer (undercut) of the edge of another film layer. In fig. 18, ahole injection layer 414, ahole transport layer 415, anemission layer 416, anelectron transport layer 417, acathode 418, and alight extraction layer 419 are taken as an example to show the patterning design of all deposition layers of the OLED light-emitting device by using the FFM process.

In the embodiments of the present application, the OLED light emitting device is partially disposed in the pixel region, and all the OLED light emitting devices may be disposed in the pixel region, which is not limited in the embodiments of the present application.

Step 008: asecond encapsulation layer 420 is fabricated. Referring to fig. 19, in the specific fabrication of thesecond encapsulation layer 420, first, SiO may be deposited using CVD, ALD, or the like₂SiNx or Al₂O₃As asecond encapsulation layer 420. Then, thesecond encapsulation layer 420 may be patterned by coating photoresist, exposing, developing, etching, stripping the photoresist, and the like, so as to form a separatesecond encapsulation layer 420 over the pixel unit corresponding to each pixel unit. Since thefirst encapsulation layer 410 between the adjacent pixel units is also independently disposed, thesecond encapsulation layer 420 and thefirst encapsulation layer 410 of the pixel unit may be in sealing contact through theside encapsulation region 4122 of the pixel definition layer 412.Fig. 19 shows the pixel packing at the position where the third metal grid line M3 and thecathode 418 have no interconnection relationship, and fig. 20 shows the pixel packing at the position where the third metal grid line M3 and thecathode 418 have interconnection relationship.

In the above manufacturing process steps of the display panel, since thesecond encapsulation layer 420 and thefirst encapsulation layer 410 are respectively formed corresponding to each pixel unit, independent encapsulation of each pixel unit can be realized, that is, a pixel-level encapsulation structure of the display panel is formed. Like this, through the encapsulation relation between disconnection pixel unit and the pixel unit, can avoid forming the encapsulation layer of large scale to can effectually avoid including this display panel's OLED flexible display screen under scenes such as buckling, curling, free deformation, the problem that the water oxygen that the encapsulation layer fracture leads to sees through. In addition, the OLED flexible display screen can be truly folded in multiple directions, curled, freely deformed and bent in a small radius, and truly and freely flexible packaging is realized.

In addition, thepixel defining layer 412 has rugged grooves and bumps, which can be transferred to thesecond encapsulation layer 420. However, in order to facilitate the subsequent processing, referring to fig. 21, thesecond planarization layer 421 may be further formed on the display panel formed after the step 008. In addition, thesecond planarization layer 421 may cover the foreign substance to prevent the foreign substance from penetrating through another film layer disposed on thesecond planarization layer 421.

Further, referring to fig. 22, a full-surfacethird encapsulation layer 422 may be further formed on thesecond planarization layer 421, and thethird encapsulation layer 422 may be SiO₂SiNx or Al₂O₃And depositing and forming to form the whole water and oxygen barrier package on the display panel, so that a combined package mode of a pixel-level package structure and a panel-level package structure is formed on the display panel at the same time, and the water and oxygen barrier package effect of the display panel is further improved.

At the end of the manufacturing process of the display panel, laser may be used to irradiate the contact surface between thecarrier layer 401 and the first substratematerial layer PI 1, so that thecarrier layer 401 and the first substratematerial layer PI 1 lose viscosity, and thecarrier layer 401 is removed, thereby obtaining a flexible display panel.

After the display panel is processed, the display panel can be cut according to the size requirement of a specific OLED flexible display screen; then attaching the touch panel and the polarizer, and performing necessary binding process to realize electric connection; then, attaching a flexible cover plate, a heat-dissipation copper foil, a protective film and the like; and finally, customizing functional assembly aiming at the OLED flexible display screen, and performing necessary performance inspection to complete the manufacture of the OLED flexible display screen.

Referring to fig. 23, in some embodiments of the present application, there is also provided a display panel including a substrate, a thin-film transistor layer, apixel defining layer 412, a pixel unit, and an encapsulation structure for encapsulating the pixel unit. Thepixel defining layer 412 has a pixel region and a side packaging region disposed around the pixel unit packaged by the packaging structure. Thepixel defining layer 412 may be formed by slit coating a photoresist-type organic material on the thin film transistor layer, and may be processed by exposing and developing to obtain a pixel region and a side packaging region.

The thin-film transistor layers may include, but are not limited to, abuffer layer 403, an active layer, agate insulating layer 405, an inter-metaldielectric layer 406, aninterlayer dielectric layer 408, and afirst planarization layer 409, which are stacked. Thebuffer layer 403, thegate insulating layer 405, the inter-metaldielectric layer 406 and theinterlayer dielectric layer 408 are usually made of SiO₂SiNx or Al₂O₃The inorganic layer structure made of inorganic material has better water and oxygen barrier function, so that the inorganic layer structure of the thin film transistor layer can be used as the first packaging layer in the embodiment. In addition, in this embodiment, a via hole is further formed in a position on the thin-film transistor layer corresponding to the side package region, where the via hole is used to expose an inorganic layer structure (such as theinterlayer dielectric layer 408, the inter-metaldielectric layer 406, thegate insulating layer 405, or the buffer layer 403) of the thin-film transistor layer, for example, in fig. 23, the via hole on the thin-film transistor layer exposes theinterlayer dielectric layer 408.

In the embodiments of the present application, the pixel unit may include, but is not limited to, an OLED light emitting device. Wherein, a part or the whole of the OLED light-emitting device is arranged in the pixel area. When the package structure is specifically configured, the package structure is used as thesecond package layer 420 to correspondingly cover each pixel unit, that is, each pixel unit is packaged by one package structure. Thesecond packaging layer 420 penetrates through the side packaging area and the through hole in the thin film transistor layer and is in sealing contact with the inorganic layer structure (such as the interlayer dielectric layer 408) of the thin film transistor layer, so that each pixel unit is coated by the inorganic layer structure (such as the interlayer dielectric layer 408) of the thin film transistor layer and thesecond packaging layer 420, independent packaging of each pixel unit is achieved, namely a pixel-level packaging structure is formed, and therefore the formation of a large packaging layer can be avoided, and the problem that water and oxygen penetrate due to cracking of the packaging layer under the conditions of bending, curling, free deformation and the like of the OLED flexible display screen comprising the display panel can be effectively avoided.

It should be noted that, taking fig. 23 as an example, in the present embodiment, the pixel unit includes an OLED light emitting device, aplanarization layer 409, a source electrode S, and a drain electrode D. Optionally, the pixel unit may further include aninterlayer dielectric layer 408; optionally, the pixel unit may further include an inter-metaldielectric layer 406 and a gate G.

In addition, in this embodiment, a plurality of pixel units (the number of the plurality of pixel units is less than the total number of the pixel units of the display panel) may be packaged by the same package structure as a whole. Referring to fig. 6, for example, for a display panel having a fixed single folding direction (the curve with an arrow in the figure indicates the folding direction), all pixel units may be grouped in a column or row manner to form a column or row packaging structure to package the pixel units. Therefore, the bending performance of the display panel is improved, and the manufacturing difficulty and the manufacturing cost are reduced. With continued reference to fig. 6, in other embodiments of the present application, several adjacent pixel units may be further encapsulated by an encapsulation structure (see the dashed-dotted rectangle). Since each pixel unit is independently packaged, or the pixel units of a plurality of pixel units, the number of which is less than the total number of the pixel units of the display panel, are packaged by the same packaging structure, which is discussed with respect to the pixel units of the display panel, both of the above two packaging structures are referred to as pixel-level packaging structures in the present application.

In the embodiment, the pixel units of the display panel are independently packaged, so that each pixel unit or n (n is less than the total number of the pixel units of the display panel) pixel units are packaged by one packaging structure (pixel-level packaging structure), the bending characteristic of the display panel can be effectively improved, the possibility that the packaging structure is damaged in the bending process of the display panel is reduced, the problems of failure of an OLED light-emitting device and the like are favorably solved, and the service life of an OLED flexible display screen comprising the display panel is prolonged. In addition, in the embodiment of the application, the encapsulation structure may encapsulate one or more of the structures such as theplanarization layer 409, the source S, the drain D, theinterlayer dielectric layer 408, the inter-metaldielectric layer 406, and the gate G, besides encapsulating the OLED light emitting device, so as to protect the encapsulated structure. And the existing structure is used as a part of the packaging structure, so that the process step is omitted, and the cost and the manufacturing time are saved.

In addition, a third metal grid line M3 may be further disposed in the display panel, and thecathodes 418 of the OLED light emitting devices of the respective pixel units are respectively coupled with the third metal grid line M3. The material of the third metal grid lines M3 may be titanium-aluminum alloy or molybdenum. When the third metal grid line M3 is specifically arranged, referring to fig. 23, the third metal grid line M3 is arranged on a side of thepixel defining layer 412 away from the thin-film transistor layer; alternatively, third metal grid line M3 may be disposed on the stacked structure of thin-film transistor layers (e.g.,planarization layer 409,interlayer dielectric layer 408, or inter-metal dielectric layer 406).

With reference to fig. 23, the display panel of the embodiment of the present disclosure may further include a supportingpillar 413 disposed on thepixel defining layer 412, where the supportingpillar 413 may be a photoresist type supporting pillar. By arranging the supportingcolumns 413 on thepixel defining layer 412, in the process of forming the OLED light-emitting device by evaporation, an evaporation mask plate for forming each functional layer of the OLED light-emitting device by evaporation is effectively prevented from contacting the display panel, so that the product yield of the display panel is improved.

In addition to the above structure, the display panel may further include asecond planarization layer 421, where thesecond planarization layer 421 is disposed on a side of thesecond encapsulation layer 420 away from the thin-film transistor layer. By providing thesecond planarizing layer 421, a smooth processing surface can be provided for the subsequent processes. In addition, thesecond planarization layer 421 may cover the foreign substance to prevent the foreign substance from penetrating through another film layer disposed on thesecond planarization layer 421. Further, with continued reference to fig. 23, a full-sidedthird encapsulation layer 422 may also be disposed on thesecond planarization layer 421, and in this embodiment, the full-sided encapsulation structure disposed on the display panel is referred to as a panel-level encapsulation structure. Therefore, the display panel is provided with the pixel level packaging structure and the panel level packaging structure at the same time, so that the water and oxygen blocking effect of the display panel is improved.

When the display panel of the present embodiment is manufactured, the manufacturing process is similar to the manufacturing process of the display panel shown in fig. 9 to 22, and the detailed description is omitted here. The manufacturing process of the display panel of the embodiment is different from the manufacturing process of the display panel in that: in this embodiment, a via hole for exposing the inorganic layer structure (e.g., interlayer dielectric layer 408) of the thin film transistor layer needs to be opened at a position on the thin film transistor layer corresponding to the side encapsulation region of the pixel definition layer, so that when thesecond encapsulation layer 420 is formed, thesecond encapsulation layer 420 can be in sealed contact with the inorganic layer structure (e.g., interlayer dielectric layer 408) of the thin film transistor layer through the via hole, thereby implementing pixel-level encapsulation of the display panel. Illustratively, a process for preparing the display panel of this embodiment includes the following steps:

step 001: and manufacturing a substrate. Illustratively, the substrate comprises a first substrate material layer, an isolation layer and a second substrate material layer which are sequentially stacked.

Step 002: and forming a thin film transistor layer on the substrate, wherein the thin film transistor layer comprises inorganic material layers, such as one or more of a buffer layer, a gate insulating layer, an intermetallic dielectric layer and an interlayer dielectric layer.

Step 003: and a first via hole and a second via hole are formed in the thin film transistor layer. The first via hole is used for exposing the drain electrode of the thin film transistor layer, and the second via hole extends to any inorganic layer structure of the thin film transistor layer.

Step 004: and (5) manufacturing an anode. The specific manufacturing process can refer to the manufacturing process of the display panel in the above embodiments, and details are not repeated here. The anode may be sealed by a first via connected to the drain contact.

Step 005: and manufacturing a pixel definition layer. The specific manufacturing process can refer to the manufacturing process of the display panel in the above embodiments, and details are not repeated here. The formed pixel definition layer is provided with a pixel area and a side packaging area, the OLED light-emitting device of the pixel unit can be formed in the pixel area, and the side packaging area and the second through hole are oppositely arranged so as to expose the inorganic layer of the thin film transistor layer, so that the pixel unit can be conveniently packaged subsequently.

Step 006: and manufacturing a third metal grid line interconnected with the cathode so as to connect the cathode of the OLED light-emitting device of each pixel unit. The specific manufacturing process can refer to the manufacturing process of the display panel in the above embodiments, and details are not repeated here.

Step 007: and manufacturing a support pillar. The specific manufacturing process of the supporting pillar can refer to the manufacturing process of the display panel in the above embodiments, and is not described herein again. By manufacturing the supporting columns on the pixel defining layer, the mask plate can be effectively prevented from contacting the surface of the display panel in the subsequent evaporation process of forming the OLED light-emitting device.

Step 008: and manufacturing a patterned OLED light-emitting device. When the OLED light emitting device is formed in the pixel region of the pixel defining layer, the OLED light emitting device may be partially disposed in the pixel region, or the OLED light emitting device may be entirely disposed in the pixel region. In addition, the layer structure and the specific manufacturing process of the OLED light emitting device can refer to the manufacturing process of the display panel in the above embodiments, and are not described herein again.

Step 009: and manufacturing the packaging structure. First, SiO can be deposited using CVD, ALD, and the like₂SiNx or Al₂O₃Forming a full-face sealAnd (5) installing a structural layer. Then, through the processes of coating photoresist, exposing, developing, etching, stripping the photoresist and the like, the whole surface of the packaging structure layer can be patterned so as to form an independent packaging structure above the pixel unit corresponding to each pixel unit. The inorganic material layers of the encapsulation structure and the thin-film transistor layer may be in sealing contact through the side encapsulation regions of the pixel definition layer.

In addition, the pixel defining layer has rugged grooves and bumps, which can be transferred to the package structure. However, in order to facilitate the subsequent processing, a planarization layer may be further formed on the display panel formed after the step 009. In addition, the planarization layer can also cover the foreign matters, so that the foreign matters are prevented from penetrating through other film layers arranged on the planarization layer. Further, a third encapsulation layer may be formed over the planarization layer.

In addition, since in some embodiments of the present application, the substrate may include a first substratematerial layer PI 1, anisolation layer 402, and a second substratematerial layer PI 2, which are stacked, wherein theisolation layer 402 is typically made of SiO₂SiNx or Al₂O₃And the inorganic layer structure made of inorganic materials has better water and oxygen barrier effect. Thus, in some embodiments of the present application, the inorganic layer structure (e.g., the isolation layer 402) of the substrate may be used as the first encapsulation layer. At this time, a via hole may be formed in the substrate and the thin-film transistor layer at a position corresponding to the side package region, and the via hole may expose the inorganic layer structure (e.g., the isolation layer 402) of the substrate. The package of the pixel unit is similar to the above embodiments, and is not described herein again.

The thin-film transistor layers in this embodiment may include, but are not limited to, a buffer layer, an active layer, a gate insulating layer, an inter-metal dielectric layer, an interlayer dielectric layer, and a first planarization layer, which are stacked. Wherein, the buffer layer, the gate insulating layer, the inter-metal dielectric layer and the interlayer dielectric layer are usually made of SiO₂SiNx or Al₂O₃The inorganic layer structure made of inorganic material has better water and oxygen barrier function, so that the inorganic layer structure of the thin film transistor layer can be used as the first packaging layer in the embodiment.

When the packaging structure is specifically arranged, the packaging structure is used as a second packaging layer to correspondingly cover each pixel unit one by one, namely, each pixel unit is packaged by one packaging structure. The second packaging layer penetrates through the side packaging area and the through hole in the thin film transistor layer and is in sealing contact with the inorganic layer structure (such as an interlayer dielectric layer) of the thin film transistor layer, so that each pixel unit is coated by the inorganic layer structure (such as the interlayer dielectric layer) of the thin film transistor layer and the second packaging layer, independent packaging of each pixel unit is achieved, and a pixel-level packaging structure is formed. It should be noted that, in the present embodiment, the pixel unit includes an OLED light emitting device, a planarization layer, a source electrode, and a drain electrode. Optionally, the pixel unit may further include an interlayer dielectric layer; optionally, the pixel unit may further include an inter-metal dielectric layer and a gate.

The embodiment of the present application further provides an electronic device, which includes a middle frame, a rear shell, a printed circuit board, and any of the flexible display screens in the foregoing all embodiments. The middle frame can be used for bearing a printed circuit board and a flexible display screen, the flexible display screen and the printed circuit board are located on two sides of the middle frame, and the rear shell is located on one side, far away from the middle frame, of the printed circuit board.

The electronic equipment of this application embodiment can be collapsible equipment, because this electronic equipment's flexible display screen is at the folding in-process, and the risk of its display panel's encapsulation layer fracture is lower, consequently can avoid water oxygen to permeate through the encapsulation layer and get into display panel, leads to the problem that flexible display screen shows the inefficacy.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.