CN113569764A - Optical fingerprint identification module under screen of axial displacement - Google Patents

Abstract

Translated fromChinese

本发明属于微型传感器技术领域，公开了一种轴向移动的屏下光学指纹识别模块，设置在具有屏幕的终端设备内，用于获取贴合在屏幕对应位置的手指指纹信息，包括可相对活动的镜头模组和传感器，由镜头模组将屏幕外的指纹反射光导向传感器进行成像；还包括至少与镜头模组、传感器其中任一个连接的致动模组，所述致动模组推动其中一个或多个沿光线入射方向运动来补偿指纹面与屏幕之间的间距差。

The invention belongs to the technical field of micro-sensors, and discloses an axially movable under-screen optical fingerprint identification module, which is arranged in a terminal device with a screen and is used for acquiring fingerprint information of a finger attached to a corresponding position of the screen, including a relative movable fingerprint recognition module. The lens module and the sensor, the lens module guides the off-screen fingerprint reflected light to the sensor for imaging; it also includes an actuating module connected to at least any one of the lens module and the sensor, and the actuating module pushes the One or more moves along the light incident direction to compensate for the difference in spacing between the fingerprint surface and the screen.

Description

Optical fingerprint identification module under screen of axial displacement

Technical Field

The invention belongs to the technical field of micro sensors, and particularly relates to an axially moving optical fingerprint identification module under a screen.

Background

The fingerprint identification technology is one of the most widely used biometric identification technologies, namely, the biometric identification technology, which is used for identifying the identity of a person by using the inherent physiological characteristics or behavior characteristics of the human body, has wide application prospects in the fields of identity authentication identification and network security due to the advantages of convenience, safety and the like of biometric identification, and the available biometric identification technologies include fingerprints, human faces, voiceprints, irises and the like, wherein the fingerprints are the most widely applied technologies. At present, fingerprint identification technologies can be classified into three categories: capacitive fingerprint identification, optical screen fingerprint identification and ultrasonic fingerprint identification.

Because mobile terminal equipment such as current cell-phones all can adopt biological identification technique as a safety guarantee measure, nevertheless along with the continuous development of technique, people also improve gradually to the demand of full face screen, can enlarge display area as far as possible on effectual terminal equipment, will certainly crowd the space that occupies other functional modules. The existing fingerprint identification technology needs to be arranged outside a shell and directly contacts with the surface of a finger, and in order to further improve the external integrity of terminal equipment such as a mobile phone, various manufacturers research and develop the fingerprint identification technology under a screen to replace an entity identification key. The optical screen fingerprinting and the ultrasonic fingerprinting mentioned in the above are feasible solutions.

The ultrasonic fingerprint identification technology has higher cost and complex structure, and the optical fingerprint identification equipment and the solution are mature and have lower cost. However, since optical fingerprint recognition has certain requirements on the light transmittance of the screen, special processing is inevitably performed on the screen at the recognition area when the requirements are met, and the normal display effect of the screen is influenced by the special processing. Therefore, in order to ensure the appearance of the whole screen, the screen identification area is not too large, the existing identification equipment generally adopts a fixed structure, the structure cannot acquire more light reflection information in a limited screen identification area, and different from ultrasonic waves, optical identification is carried out by comparison and identification according to acquired image information, once a protective film is attached to the surface of the structure or finger pressing force causes screen deformation, a fingerprint image acquired under the original determined focal length condition becomes fuzzy, so that the identification rate is influenced, and the fixed structure is one of the reasons that the identification rate of a fingerprint identification module under the existing optical screen is slower.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides an axially-moving optical fingerprint identification module under a screen, which can compensate and optimize image blurring caused by sticking protective stickers with different thicknesses on the screen.

The technical scheme adopted by the invention is as follows:

in a first aspect, the invention provides an axially-moving underscreen optical fingerprint identification module, which is arranged in a terminal device with a screen, is used for acquiring finger fingerprint information attached to a corresponding position of the screen, and comprises a lens module and a sensor which can move relatively, wherein fingerprint reflected light outside the screen is guided to the sensor by the lens module for imaging;

the fingerprint surface adjusting device further comprises an actuating module which is at least connected with any one of the lens module and the sensor, and the actuating module pushes one or more of the lens module and the sensor to move along the incident direction of light rays so as to compensate the distance difference between the fingerprint surface and the screen.

The principle of optical fingerprint identification under the screen is that a light source irradiates one side of a finger fingerprint attached to the screen, so that fingerprint reflected light generated by the light source can be fed back to a sensor, the fingerprint reflected light is converted into an electric signal after being identified by the sensor and is sent to the outside, and an external processor processes, analyzes and compares acquired fingerprint image data.

The devices provided with such identification modules are generally compact mobile terminals with a display (mainly a touch display), and there is a demand for improving the screen occupation ratio by arranging various functional modules as built-in as possible. Since the built-in sensor needs to receive external reflected light, the structure of the common LCD screen with the backlight plate cannot meet the requirement, and the screen is generally an OLED screen, and the screen in the above description is the display screen and the protective glass covering the surface of the display screen.

Although the thickness of the screen and the thickness of the protective glass are set conditions, the distance between the lens module and the sensor can be calculated and determined according to the thicknesses of the two layers of light-transmitting structures during debugging. However, due to the influence of the finger-contacting state or other obstacles such as a protective film on the outer surface of the screen, the best fingerprint influence cannot be obtained by the fixed identification module. The invention adjusts the focal length by the identification module which can move axially, wherein the actuating module can move one or two of the sensor and the lens module, and analyzes whether to focus or not according to the acquired image information by the external processing module, and can acquire distance data which needs to move by laser ranging focusing or an internal phase focusing mode, and the processing module controls the actuating module to move and push so as to finish the focusing work.

It is worth also saying that the distance between the finger-print surface and the screen is small due to the protective film or other factors, and for a common camera module, the above error influence is small and can be ignored. However, due to the optical fingerprint identification under the screen, the original light transmission amount is smaller than a normal value, the focal length of the optical fingerprint identification is small, and the optical fingerprint identification belongs to a microspur state, and the identification efficiency is influenced by the change identification of one point and one space. The actuating module is small in size, the moving stroke of the actuating module is also small, and the focusing requirement of the identification module can be fully met within a certain small moving stroke.

With reference to the first aspect, the present invention provides a first implementation manner of the first aspect, wherein the actuating module is connected to the lens module and controls the operation through an external circuit.

The actuating module directly realizes focusing by adjusting the movement of the lens module, and the sensor is fixed on the inner side of the screen of the terminal equipment and is the same as the existing miniature camera.

In combination with the first aspect, the present invention provides a second implementation manner of the first aspect, wherein the actuating module is connected with the sensor and controls the action through an external circuit.

Because the sensor has smaller thickness and weight, the driving force required by the actuating module is smaller than that for driving the lens module, so that the volume of the actuating module can be further reduced.

In combination with the first or second embodiment of the first aspect, the present invention provides a third embodiment of the first aspect, wherein the actuator module is a voice coil motor including a magnet and a coil.

The so-called voice coil motor is an electromagnetic actuating structure commonly used in a miniature camera, and mainly comprises a magnet and a coil, wherein an electrified coil can form an interaction force with the magnet in an effective magnetic field range of the magnet, and then the movement control is realized by fixing one end to move the other end or elastically connecting the two ends to have a fixed state and by means of relative movement of the two parts. Because the voice coil motor is small in size and controllable in motion, the voice coil motor can meet the moving requirement of a small stroke.

With reference to the first or second embodiment of the first aspect, the present disclosure provides a fourth embodiment of the first aspect, wherein the actuation module is a micro-electromechanical assembly.

The so-called micro-motor assembly is also an electric mechanism commonly used in mobile terminal equipment, and is generally in a screw motor structure, and the existing mobile phone lifting camera adopts the action mechanism. The volume is small, the moving stroke can be accurately controlled, and the device is also suitable for the requirements of the invention.

In combination with the third implementation manner of the first aspect, the present invention provides a fifth implementation manner of the first aspect, wherein the actuation module includes a housing disposed inside the terminal device, and the lens module and the sensor are disposed inside the housing; the lower part of the sensor is provided with a base connected through a spring plate, the sensor is provided with a coil, and the base is provided with a magnet.

With reference to the first aspect, the first or second implementation manner of the first aspect, the present invention provides a sixth implementation manner of the first aspect, and the fingerprint reflected light is formed by screen luminous irradiation.

It should be noted that, the screen itself is a light source, and the existing under-screen optical fingerprint recognition modules all set a recognition area at a corresponding position, and process the screen in the area, so as to improve the light transmittance without reducing the image quality as much as possible. Then, the specific area emits light to prompt a finger to press, and the intensity of the reflected light can meet the identification requirement due to the small distance. And the filter additionally arranged can filter other external light, and only special fingerprint emission light is reserved.

With reference to the first aspect and the first or second embodiment of the first aspect, the present invention provides a seventh embodiment of the first aspect, wherein the fingerprint reflected light is formed by reflecting an infrared emission source disposed inside the screen toward the surface of the finger.

Different from the screen excitation mode, the independently arranged infrared emission source can emit invisible light, interference can be reduced through a special light source on the basis that the service life of the light emitting unit in a screen imaging area and a screen specific area is not influenced, and the identification efficiency is improved.

With reference to the fifth implementation manner of the first aspect, the invention provides an eighth implementation manner of the first aspect, wherein an optical filter is disposed between the sensor and the lens module.

The invention has the beneficial effects that:

the invention compensates and optimizes the image blurring caused by using the protective stickers with different thicknesses by consumers, and the back focus can be adjusted according to different wavelengths to obtain the clearest image; visible light emitted by the screen is used for fingerprint identification on the surface of the skin, and infrared light is used for biological living body identification on blood vessels and blood flow in the skin;

meanwhile, the three-dimensional information of the fingerprint can be obtained by axial scanning, and the size variation of the mobile phone (including the fingerprint module) caused by temperature variation can be compensated and optimized; and the lens in the invention does not need to move.

Drawings

FIG. 1 is an external illustration of the application of the entire optical fingerprinting module of the invention on a mobile phone;

FIG. 2 is a schematic side view of the optical fingerprint recognition module according to the present invention;

FIG. 3 is an isometric view of the specific structure of the whole optical fingerprint identification module of the present invention inembodiment 1;

FIG. 4 is an isometric view of the internal structure of the whole optical fingerprint identification module of the present invention after the housing is removed inembodiment 1;

FIG. 5 is a schematic diagram illustrating the recognition of the entire optical fingerprint recognition module in the screen light-emitting reflective state according to the present invention;

FIG. 6 is a schematic diagram of the recognition of the present invention based on FIG. 5 when a protective film is coated on the screen;

fig. 7 is a schematic diagram of the entire optical fingerprint recognition module of the present invention in which an infrared light source is separately provided.

In the figure: 1-sensor, 2-optical filter, 3-lens module, 4-base, 5-shell, 6-infrared emission source, 7-screen and 8-protective film.

Detailed Description

The invention is further explained below with reference to the drawings and the specific embodiments.

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, generally described and illustrated in the figures herein, can be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present application, presented in the accompanying drawings, is not intended to limit the scope of the claimed application, but is merely representative of selected embodiments of the application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present application, it should be noted that if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are used for indicating the orientation or positional relationship based on the orientation or positional relationship shown in the drawings or the orientation or positional relationship which is usually placed when the product of the application is used, the description is only for convenience and simplicity, and the indication or suggestion that the referred device or element must have a specific orientation, be constructed in a specific orientation and be operated, and thus, should not be construed as limiting the present application. Furthermore, the appearances of the terms "first," "second," and the like in the description herein are only used for distinguishing between similar elements and are not intended to be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal", "vertical" and the like when used in the description of the present application do not require that the components be absolutely horizontal or overhanging, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present application, it should also be noted that, unless otherwise explicitly stated or limited, the terms "disposed," "mounted," "connected," and "connected" should be interpreted broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.

Example 1:

many existing smart phones mainly have a high screen occupation ratio, and better visual experience can be brought by improving the screen occupation ratio. However, since the originally necessary biometric identification module can only be adjusted and optimized, many manufacturers advance the technology of underscreen fingerprint identification, but the identification efficiency of underscreen fingerprint identification equipment on the market is lower than that of the entity identification module, and the identification success rate is obviously reduced after the protective film 8 is attached, and then all manufacturers search for improving the identification success rate.

The present embodiment discloses an optical fingerprint recognition module under a screen capable of moving axially, as shown in fig. 2 to 6, the specific structure of the module in the present embodiment is shown in the drawings, including a complete state and a split state, and the schematic diagram of the optical path of the module for fingerprint recognition under thescreen 7 is also shown.

Specifically, the module is an independent structure arranged in the mobile terminal equipment, the lighting end of the module comprises a shell 5 and abase 4 which are mutually buckled, alens module 3 and asensor 1 which are mutually independent are arranged in the shell 5, a plurality of fixed lenses are arranged in thelens module 3, and thesensor 1 is of a similar rectangular plate structure and is movably connected with the shell 5 or thebase 4 through an elastic connecting piece.

A plurality of magnets are arranged on thebase 4, a coil is arranged on the back surface or the outer annular surface of the fixing plate of thesensor 1, and ahall sensor 1 is arranged at the inner center part of the coil and used for detecting the movement distance to form a control closed loop.

The coil is connected with an external control circuit through an FPC, and the coil and the magnet generate interaction force by inputting current by the control circuit. Since the magnet is fixed on thebase 4, the coil will be pushed by the acting force and drive thewhole sensor 1 to perform directional movement. (the principle of the controllable relative motion between the magnet and the coil is common knowledge in the field, and the present embodiment does not require any driving force or control logic, and therefore is not described in detail).

Thelens module 3 is fixed in the housing 5, and the end surface of the light-entering side faces the direction of thescreen 7, and the axial direction of the lens module is vertical to thescreen 7. And the axis of thelens module 3 passes through the center of the fingerprint identification area on thescreen 7. As can be seen in fig. 1, the mobile terminal device is a full-screen smart phone, and the lower side of the front of the smart phone has an identification area, and a circular bright spot is locally formed on thescreen 7 to indicate that the user places a finger thereon.

When the finger is already attached to the corresponding area as shown in fig. 5, the circular bright spot still keeps the lighted state, and the brightness can be improved when the finger is attached to the corresponding area to increase the recognition efficiency. At this time, thescreen 7 emits light to the surface of the finger, and when the light reflected from the end face of the finger enters thescreen 7, the light can be adjusted by thelens module 3 and then emitted to thesensor 1.

In fig. 5, it can be seen that the light beam is focused on the surface of thesensor 1 after being converged by thelens module 3. The surface of thesensor 1 is also covered with theoptical filter 2, and theoptical filter 2 can filter other non-object rays and retain the fingerprint reflected light to enter thesensor 1, so that the identification precision is improved.

In fig. 6, it can be seen that thescreen 7 is covered with a protective film 8, and the finger surface originally in focus is moved upward due to the presence of the protective film 8. Since the gaps from thescreen 7 to thelens module 3 and from thelens module 3 to thesensor 1 are small, once the surface of the finger as the sampling object is displaced, the focus is liable to be out of the effective range recognized by thesensor 1. Therefore, thesensor 1 is axially moved by the coil under the control of the external mobile phone processor in the embodiment. In fig. 6, in order to adapt to the existence of the protective film 8, thesensor 1 is moved upward, so that the changed focus can fall on thesensor 1, and a clearer image can be obtained, thereby improving the recognition efficiency.

Example 2:

the present embodiment also discloses an off-screen optical fingerprint recognition module, which is different fromembodiment 1 in that, as shown in fig. 7, a single light source, i.e. an infrared emission source 6, is provided inside the terminal device in this embodiment. By being disposed near the recognition area, infrared light is projected toward the recognition area of thescreen 7. The infrared light can not only perform fingerprint identification through finger reflection, but also perform organism identification, and the mobile phone can acquire the pulse and even the blood oxygen saturation information of the user through the extraction and analysis of the reflected light information of the blood vessel.

The present invention is not limited to the above-described alternative embodiments, and various other forms of products can be obtained by anyone in light of the present invention. The above detailed description should not be taken as limiting the scope of the invention, which is defined in the claims, and which the description is intended to be interpreted accordingly.

Claims (9)

1. An optical fingerprint identification module under an axially moving screen is arranged in terminal equipment with a screen and used for acquiring finger fingerprint information attached to the corresponding position of the screen, and comprises a lens module (3) and a sensor (1) which can move relatively, wherein fingerprint reflected light outside the screen is guided to the sensor (1) by the lens module (3) for imaging;

the method is characterized in that: the fingerprint surface adjusting device further comprises an actuating module which is at least connected with any one of the lens module (3) and the sensor (1), and the actuating module pushes one or more of the lens module and the sensor to move along the incident direction of light rays so as to compensate the distance difference between the fingerprint surface and the screen.

2. The axially moving underscreen optical fingerprint recognition module of claim 1, wherein: the actuating module is connected with the lens module (3) and controls the action through an external circuit.

3. The axially moving underscreen optical fingerprint recognition module of claim 1, wherein: the actuating module is connected with the sensor (1) and controls the action through an external circuit.

4. An axially moving underscreen optical fingerprint recognition module as claimed in claim 2 or 3, wherein: the actuation module is a voice coil motor including a magnet and a coil.

5. An axially moving underscreen optical fingerprint recognition module as claimed in claim 2 or 3, wherein: the actuating module is a micro-motor assembly.

6. The axially moving underscreen optical fingerprint recognition module of claim 4, wherein: the actuating module comprises a shell (5) arranged in the terminal equipment, and the lens module (3) and the sensor (1) are arranged in the shell (5); the lower part of the sensor (1) is provided with a base connected through an elastic sheet, the sensor (1) is provided with a coil, and the base is provided with a magnet.

7. The axially moving underscreen optical fingerprint recognition module of any one of claims 1-3, wherein: the fingerprint reflection light is formed by screen luminous irradiation.

8. The axially moving underscreen optical fingerprint recognition module of any one of claims 1-3, wherein: the fingerprint reflection light is formed by reflecting an infrared emission source (6) arranged on the inner side of the screen to the surface of a finger.

9. The axially moving underscreen optical fingerprint recognition module of claim 6, wherein: and an optical filter (2) is arranged between the sensor (1) and the lens module (3).

Images