Disclosure of Invention
The invention aims to provide an array substrate, a liquid crystal display device and a driving method, which can realize wide and narrow visual angle switching in different occasions and improve the problem of uneven image quality display.
The embodiment of the invention provides an array substrate, which is provided with a plurality of scanning lines, a plurality of data lines, a plurality of pixel electrodes and a plurality of first thin film transistors, and is also provided with a plurality of common lines, a plurality of common electrodes, a plurality of second thin film transistors and a plurality of conducting bars, wherein the plurality of common lines and the plurality of data lines extend along the same direction, the plurality of data lines form a plurality of groups by taking each two adjacent data lines as a group, the plurality of common lines and the plurality of groups of data lines are arranged alternately in the scanning line direction, the plurality of scanning lines, the plurality of data lines and the plurality of common lines are defined in an insulating and crossing way to form a plurality of pixel units, each pixel unit is defined by two scanning lines, one data line and one common line, two rows of pixel units are arranged between two adjacent groups of data lines, and one common line is arranged between two rows of pixel units, each pixel unit is internally provided with a pixel electrode, each pixel electrode is connected with a scanning line and a data line which are close to the first thin film transistor through a first thin film transistor, each pixel unit is internally provided with a common electrode, each common electrode is connected with the scanning line and a common line which are close to the second thin film transistor through a second thin film transistor, the plurality of bus bars and the plurality of groups of data lines extend along the same direction and cover the plurality of groups of data lines in the direction vertical to the array substrate, and the common electrodes of one of two columns of pixel units positioned at two sides of each bus bar are connected to the bus bars.
Further, the common electrode includes a plurality of common electrode bars; the pixel electrode comprises a plurality of pixel electrode strips, and the common electrode strips and the pixel electrode strips are arranged in a crossed mode in a direction perpendicular to the array substrate.
Further, all the pixel units in each row are connected to the same scan line located at the upper side or the lower side of the pixel units in the row.
Further, the pixel units in odd number and the pixel units in even number in each row are separately connected to different scanning lines on the upper and lower sides of the pixel units in the row.
The embodiment of the invention also provides an array substrate, wherein the array substrate is provided with a plurality of scanning lines, a plurality of data lines, a plurality of pixel electrodes and a plurality of first thin film transistors, the array substrate is also provided with a plurality of common lines, a plurality of common electrodes, a plurality of second thin film transistors and a plurality of conducting bars, the plurality of common lines and the plurality of data lines extend along the same direction, the plurality of data lines form a plurality of groups by taking every two adjacent data lines as a group, the plurality of common lines and the plurality of groups of data lines are arranged alternately in the scanning line direction, the plurality of scanning lines, the plurality of data lines and the plurality of common lines are insulated and crossed to define a plurality of pixel units, each pixel unit is defined by two scanning lines, one data line and one common line, two rows of pixel units are arranged between two adjacent groups of data lines, and one common line is arranged between two rows of pixel units, each pixel unit is internally provided with a pixel electrode, each pixel electrode is connected with a scanning line and a data line which are close to the first thin film transistor through a first thin film transistor, a common electrode is arranged in every two pixel units between every two adjacent groups of data lines, each common electrode is connected with the scanning line and a common line which are close to the second thin film transistor through a second thin film transistor, the multiple bus bars and the multiple groups of data lines extend along the same direction and cover the multiple groups of data lines in the direction vertical to the array substrate, and the common electrode positioned on one side of two sides of each bus bar is connected to the bus bar.
Further, each common electrode is located in two adjacent pixel units between two groups of data lines in the scanning line direction.
Further, the common lines at odd-numbered positions in the scan line direction are connected together and applied with a first common voltage, and the common lines at even-numbered positions in the scan line direction are connected together and applied with a second common voltage.
The embodiment of the invention also provides a liquid crystal display device, which comprises an array substrate, a color film substrate arranged opposite to the array substrate and a liquid crystal layer positioned between the array substrate and the color film substrate, wherein the array substrate is the array substrate, and the color film substrate is provided with an upper electrode on the whole surface.
An embodiment of the present invention further provides a driving method of the liquid crystal display device, including:
in a first viewing angle mode, applying a reference voltage to the upper electrodes, applying a first common voltage having a smaller magnitude to the common lines positioned at odd-numbered positions in the scanning line direction, and applying a second common voltage having a smaller magnitude to the common lines positioned at even-numbered positions in the scanning line direction, so that voltage differences between all the common electrodes and the upper electrodes are smaller than a first preset value, wherein the first common voltage applied to the common lines at odd-numbered positions and the second common voltage applied to the common lines at even-numbered positions are the same as the reference voltage, and the liquid crystal display device is driven by single column inversion;
in a second viewing angle mode, a reference voltage is applied to the upper electrode, a first common voltage with a larger amplitude is applied to the common lines positioned at odd-numbered positions in the scanning line direction, a second common voltage with a larger amplitude is applied to the common lines positioned at even-numbered positions in the scanning line direction, the voltage difference between all the common electrodes and the upper electrode is larger than a second preset value, wherein the second preset value is larger than or equal to the first preset value, the first common voltage applied to the common lines at odd-numbered positions and the second common voltage applied to the common lines at even-numbered positions are both alternating voltages and have opposite polarities, the first common voltage and the second common voltage are both inverted once per frame, and the liquid crystal display device adopts double row inversion driving.
Further, the liquid crystal layer adopts positive liquid crystal molecules, the first visual angle mode is a wide visual angle mode, and the second visual angle mode is a narrow visual angle mode; alternatively, the liquid crystal layer uses negative liquid crystal molecules, the first viewing angle mode is a narrow viewing angle mode, and the second viewing angle mode is a wide viewing angle mode.
The array substrate, the liquid crystal display device and the driving method provided by the embodiment of the invention are realized by switching the voltage for controlling the switching of the wide and narrow viewing angles from the viewing angle control electrode on the color film substrate side to the common electrode on the array substrate side, and additionally adding a common line and a thin film transistor (namely, a second thin film transistor) to be connected with each common electrode for carrying out the charging control of the common voltage. When each scanning line is opened, the first thin film transistor and the second thin film transistor which are connected with the scanning line are opened, the pixel electrode and the common electrode in the pixel unit are synchronously charged through the data line and the common line respectively, each charged pixel unit and the pixel unit to be charged are not influenced by voltage coupling, signal coupling can be effectively reduced, the problem of uneven picture display (Mura) caused by inconsistent coupling influence of signals on pixels at different positions in a panel is solved, and display image quality is improved. Therefore, the frame frequency of the liquid crystal display device can be maintained at a low frequency of 60Hz, which is beneficial to reducing power consumption and increasing the charging time and charging effect of pixels. The bus bar and the common electrode have the same voltage signal, a storage capacitor is formed between the bus bar and the pixel electrode, and the electrode bar covers the data line, so that the electric field of the data line can be shielded, and light leakage is prevented.
Detailed Description
To further illustrate the technical means and effects of the present invention adopted to achieve the predetermined objects, the following detailed description of the embodiments, structures, features and effects of the present invention will be made with reference to the accompanying drawings and examples.
[ first embodiment ]
Referring to fig. 3 to 6, a liquid crystal display device according to a first embodiment of the present invention includes an array substrate 20, a color filter substrate 30 disposed opposite to the array substrate 20, and a liquid crystal layer 40 disposed between the array substrate 20 and the color filter substrate 30.
The array substrate 20 is provided with a plurality of scan lines 21, a plurality of data lines 22, a plurality of common lines 24, a plurality of pixel electrodes 23, a plurality of common electrodes 25, a plurality of first thin film transistors 26, a plurality of second thin film transistors 27, and a plurality of conductive bars 29.
The common lines 24 and the data lines 22 extend in the same direction, for example, the common lines 24 and the data lines 22 extend in a vertical direction, and the scan lines 21 extend in a horizontal direction. The plurality of data lines 22 are grouped into a plurality of groups by two adjacent data lines, the plurality of common lines 24 and the plurality of groups of data lines 22 are arranged alternately in the direction of the scanning line 21, that is, a common line 24 is arranged between two adjacent groups of data lines 22, and a group of data lines 22 is arranged between two adjacent groups of data lines 24. Specifically, the common lines 24 and the data lines 22 may be located at the same layer on the array substrate 20 and may be formed simultaneously by the same etching process.
The plurality of scanning lines 21, the plurality of data lines 22 and the plurality of common lines 24 are defined in an insulated crossing manner to form a plurality of pixel units P, and each pixel unit P is defined by two scanning lines 21, one data line 22 and one common line 24. Each pixel unit P may serve as a sub-pixel of the liquid crystal display device.
Two columns of pixel units P are disposed between two adjacent groups of data lines 22, and one common line 24 is disposed between the two columns of pixel units P, i.e., in the present embodiment, by disposing the data lines 22 in close proximity to each other in groups of two, a space can be left between the two columns of pixel units P to dispose the common line 24.
Each pixel unit P is provided with a pixel electrode 23, and each pixel electrode 23 is connected to the scan line 21 and the data line 22 adjacent to the first thin film transistor 26 through the first thin film transistor 26.
In this embodiment, a common electrode 25 is provided in each pixel unit P (i.e., each common electrode 25 covers one pixel unit P), and each common electrode 25 is connected to the scan line 21 and the common line 24 adjacent to the second thin film transistor 27 through the second thin film transistor 27.
In the present embodiment, all the pixel units P in each row are connected to the same scan line 21 located at the upper side of the pixel units P in the row. In other embodiments, all the pixel units P in each row may also be connected to the same scan line 21 at the lower side of the row of pixel units P. The thin film transistors are arranged on the same side, so that the pixel unit P has a larger aperture ratio on one hand, and has a more regular punching position in the process of manufacturing the thin film transistors on the other hand.
Specifically, as shown in fig. 5, the first thin film transistor 26 includes a gate electrode 261, an active layer 262, a source electrode 263 and a drain electrode 264, wherein the gate electrode 261 is electrically connected to the corresponding scan line 21, the gate electrode 261 can be independently disposed or can be a part of the scan line 21, the source electrode 263 is electrically connected to the corresponding data line 22, and the drain electrode 264 is electrically connected to the corresponding pixel electrode 23.
Specifically, the second thin film transistor 27 includes a gate electrode 271, an active layer 272, a source electrode 273 and a drain electrode 274, wherein the gate electrode 271 is electrically connected to the corresponding scan line 21, the gate electrode 271 can be independently disposed or can be a part of the scan line 21, the source electrode 273 is electrically connected to the corresponding common line 24, and the drain electrode 274 is electrically connected to the corresponding common electrode 25.
In this embodiment, the plurality of pixel electrodes 23 and the plurality of common electrodes 25 are located in different layers, and an insulating layer is interposed between the plurality of pixel electrodes 23 and the plurality of common electrodes 25, the pixel electrodes 23 are located above the common electrodes 25, each common electrode 25 is in a slit structure, each pixel electrode 23 is also in a slit structure, the common electrodes 25 include a plurality of common electrode strips 251, the pixel electrodes 23 include a plurality of pixel electrode strips 231, and the common electrode strips 251 of the common electrodes 25 and the pixel electrode strips 231 of the pixel electrodes 23 are arranged in a cross manner in a direction perpendicular to the array substrate 20, that is, each common electrode strip 251 is located between two adjacent pixel electrode strips 231 in a direction perpendicular to the array substrate 20, or each pixel electrode strip 231 is located between two adjacent common electrode strips 231 in a direction perpendicular to the array substrate 20.
As shown in fig. 4 and 5, the array substrate 20 is further provided with a first via hole 201 for conducting the pixel electrode 23 to the drain electrode 264 of the first thin film transistor 26 and a second via hole 202 for conducting the common electrode 25 to the drain electrode 274 of the second thin film transistor 27.
As shown in fig. 3, the common lines 24 (i.e., S1, S3, S4, …) positioned at odd-numbered bits in the direction of the scan line 21 are connected together and applied with a first common voltage Vcom1, and the common lines 24 (i.e., S2, S4, S6, …) positioned at even-numbered bits in the direction of the scan line 21 are connected together and applied with a second common voltage Vcom 2. Specifically, the array substrate 20 is further provided with a first signal line 28a and a second signal line 28b in the non-display region, the common lines 24 located at odd-numbered positions are connected together by the first signal line 28a and uniformly applied with a first common voltage Vcom1, and the common lines 24 located at even-numbered positions are connected together by the second signal line 28b and uniformly applied with a second common voltage Vcom 2.
In this embodiment, the plurality of conductive strips 29 extend along the data lines 22, and each conductive strip 29 is disposed above each group of two data lines 22 disposed in close proximity. The row of common electrodes 25 located to the left or right of the conductive strip 29 is connected to the conductive strip 29, and in this embodiment, the row of common electrodes 25 located to the right of the conductive strip 29 is connected to the conductive strip 29.
The pixel electrode 23 and the common electrode 25 may be made of a transparent conductive material such as Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO). The plurality of conductive strips 29 are made of a metal with a low resistivity, such as Mo, Al, Au, Ag, Cu, and are directly connected to the corresponding common electrodes 25 in a contact manner. In the direction perpendicular to the array substrate 20, the metal bus bars 29 overlap the data lines 22 and completely cover the data lines 22 located therebelow (i.e., the width of each bus bar 29 along the scan line 21 is greater than or equal to the width of each group of data lines 22 located immediately below along the scan line 21), so that the aperture ratio of the pixel unit P is not affected. Then, the conductive strips 29 and the common electrode 25 have the same voltage signal, a storage capacitor is formed between the common electrode and the pixel electrode 23, and the electrode strips 29 cover the data lines 22, so as to shield the electric field of the data lines 22 and prevent light leakage.
As shown in fig. 6, a color filter substrate 30 is provided with a color resist layer 31, a Black Matrix (BM)32, and an upper electrode 33. The color resist layer 31 is, for example, R, G, B color resist. The upper electrode 33 is a planar electrode over the entire surface, i.e., the entire surface of the upper electrode 33 covers the display region. The color resist layer 31 and the black matrix 32 are provided on the inner surface of the color filter substrate 30 on the side facing the liquid crystal layer 40, and the other film layers are provided on the color resist layer 31 and the black matrix 32. In this embodiment, a planarization layer 35 is further disposed on the color filter substrate 30, the planarization layer 35 covers the color resist layer 32 and the black matrix 31, and the upper electrode 33 is formed on the planarization layer 35.
In this embodiment, the liquid crystal molecules in the liquid crystal layer 40 are positive liquid crystal molecules, and the positive liquid crystal molecules have the advantage of fast response. As shown in fig. 6, in an initial state (i.e., a state where no voltage is applied to the liquid crystal display device), the positive liquid crystal molecules in the liquid crystal layer 40 assume a lying posture substantially parallel to the substrates 20, 30, i.e., a long axis direction of the positive liquid crystal molecules is substantially parallel to the surfaces of the substrates 20, 30. In practical applications, the positive liquid crystal molecules in the liquid crystal layer 40 and the substrates 20 and 30 may have a small initial pretilt angle, which may range from 10 degrees or less, that is: 0 DEG ≦ theta ≦ 10 deg.
In this embodiment, the liquid crystal display device can be switched between the wide viewing angle mode and the narrow viewing angle mode by controlling the voltage signals applied to the upper electrode 33 of the color filter substrate 30 and the common electrode 25 of the array substrate 20.
Wide view angle mode: referring to fig. 3 and 6, in the embodiment, in the wide viewing angle mode, a reference voltage is applied to the upper electrode 33 of the color filter substrate 30, a first common voltage Vcom1 with a smaller amplitude is applied to the common lines 24 located at odd-numbered positions in the direction of the scan lines 21 on the array substrate 20 through the first signal line 28a, and a second common voltage Vcom2 with a smaller amplitude is applied to the common lines 24 located at even-numbered positions in the direction of the scan lines 21 on the array substrate 20 through the second signal line 28b, so that voltage differences between all the common electrodes 25 and the upper electrode 33 are smaller than a first preset value (e.g., smaller than 1V). At this time, since the voltage difference between the common electrode 25 and the upper electrode 33 is small, the tilt angle of the liquid crystal molecules in the liquid crystal layer 40 is hardly changed and is maintained in the lying posture, so that the liquid crystal display device realizes normal wide viewing angle display.
In this embodiment, in the wide viewing angle mode, the reference voltage applied by the upper electrode 33 may be a constant 0V, and the common voltages Vcom1, Vcom2 applied through the first signal line 28a and the second signal line 28b may also be a constant 0V, so that the common voltage applied to each common electrode 25 is the same as the reference voltage, and the voltage difference between each common electrode 25 and the upper electrode 33 is zero, thereby achieving a good wide viewing angle effect. However, the present embodiment is not limited thereto, and the common voltages Vcom1, Vcom2 applied through the first and second signal lines 28a, 28b may be a direct current voltage or an alternating current voltage other than 0V in the wide viewing angle mode as long as the voltage difference between each common electrode 25 and the upper electrode 33 is made smaller than the first preset value (e.g., 1V).
Fig. 7 is a schematic diagram of driving waveforms of the liquid crystal display device in fig. 6 at a wide viewing angle, and referring to fig. 3, fig. 6 and fig. 7, in this embodiment, the liquid crystal display device adopts single column inversion driving (column inversion) at the time of displaying at the wide viewing angle, and the first common voltage Vcom1 applied to the odd-numbered common lines 24 is equal to the second common voltage Vcom2 applied to the even-numbered common lines 24, for example, both are 0V. The applied data voltages on the respective data lines D1, D2, D3, … are reversed in polarity once per frame.
Narrow view angle mode: referring to fig. 3 and 8, in the embodiment, in the narrow viewing angle mode, a reference voltage is applied to the upper electrode 33 of the color filter substrate 30, a first common voltage Vcom1 with a larger amplitude is applied to the common lines 24 located at odd-numbered positions in the direction of the scan lines 21 on the array substrate 20 through the first signal line 28a, and a second common voltage Vcom2 with a larger amplitude is applied to the common lines 24 located at even-numbered positions in the direction of the scan lines 21 on the array substrate 20 through the second signal line 28b, so that voltage differences between all the common electrodes 25 and the upper electrode 33 are greater than a second preset value (e.g., greater than 1.5V), where the second preset value is greater than or equal to the first preset value. At this time, because the voltage difference between the common electrode 25 and the upper electrode 33 is large, a strong vertical electric field E (as shown by an arrow in fig. 8) is generated in the liquid crystal cell between the array substrate 20 and the color film substrate 30, and the positive liquid crystal molecules rotate in a direction parallel to the electric field lines under the action of the electric field, so that the positive liquid crystal molecules are deflected under the action of the vertical electric field E, the tilt angle between the liquid crystal molecules and the substrates 20 and 30 is increased and tilted, the liquid crystal molecules are changed from the lying posture to the inclined posture, the liquid crystal display device has large-angle light leakage, the contrast is reduced in the oblique direction, the viewing angle is narrowed, and the liquid crystal display device finally realizes narrow-viewing-angle display.
In this embodiment, in the narrow viewing angle mode, the reference voltage applied by the upper electrode 33 may be a constant 0V, and the magnitudes of the first common voltage Vcom1 and the second common voltage Vcom2 applied to each common electrode 25 may be selected to be greater than 3V (i.e., | Vcom1| ≧ 3V, | Vcom2| ≧ 3V), so that the voltage difference between each common electrode 25 and the upper electrode 33 is greater than 3V, and a good narrow viewing angle effect can be achieved.
Fig. 9 is a schematic diagram of driving waveforms of the liquid crystal display device in fig. 8 at a narrow viewing angle, please refer to fig. 3, 8 and 9, in this embodiment, the liquid crystal display device adopts a 2column inversion driving (2column inversion) at the narrow viewing angle, the first common voltage Vcom1 applied to the odd-numbered common lines 24 and the second common voltage Vcom2 applied to the even-numbered common lines 24 are ac voltages with larger amplitudes and opposite polarities, the first common voltage Vcom1 and the second common voltage Vcom2 are both changed in polarity once per frame, and the applied data voltages on the data lines D1, D2, D3 and … are also changed in polarity once per frame.
As shown in fig. 6 and 8, the liquid crystal display device further includes a driving circuit 60, and the driving circuit 60 applies a required voltage signal to each of the upper electrode 33 of the color filter substrate 30 and the common electrode 25 of the array substrate 20. In order to apply voltage signals to the upper electrodes 33 of the color filter substrate 30, the array substrate 20 may be conducted to the color filter substrate 30 through the conductive adhesive 70 in the peripheral non-display region of the display panel, the driving circuit 60 provides voltage signals to the array substrate 20, and the array substrate 20 applies the voltage signals to the upper electrodes 33 of the color filter substrate 30 through the conductive adhesive 70.
In this embodiment, the switching of the wide and narrow viewing angles is realized by switching the voltage for controlling the switching of the wide and narrow viewing angles from the viewing angle control electrode on the color film substrate side to the common electrode 25 on the array substrate side, and by arranging the data lines 22 in a manner that every two data lines are arranged in close proximity to each other as a group and a space is left between two rows of pixel units P to arrange an additional common line 24 and a thin film transistor (i.e., a second thin film transistor 27) to be connected to each common electrode 25 for charging control of the common voltage, the switching of the wide and narrow viewing angles can be realized without adding an additional manufacturing process. The frame frequency of the liquid crystal display device can be maintained at a low frequency of 60Hz, which is beneficial to reducing power consumption and increasing the charging time and the charging effect of pixels.
[ second embodiment ]
Referring to fig. 10, a liquid crystal display device according to a second embodiment of the present invention is different from the first embodiment in that, in the present embodiment, the odd-numbered pixel cells P and the even-numbered pixel cells P in each row are separately connected to different scan lines 21 on the upper and lower sides of the row of pixel cells P, wherein the odd-numbered pixel cells P in each row are connected to the scan lines 21 on the upper side of the row of pixel cells P, and the even-numbered pixel cells P in each row are connected to different scan lines 21 on the lower side of the row of pixel cells P.
For other structures and operation principles of this embodiment, reference may be made to the first embodiment, which is not described herein again.
[ third embodiment ]
Referring to fig. 11, a liquid crystal display device according to a third embodiment of the present invention is different from the first embodiment in that in the present embodiment, a common electrode 25 is disposed in every two pixel units P between two adjacent sets of data lines 22 (i.e., each common electrode 25 covers two pixel units P at the same time), and each common electrode 25 is connected to a scan line 21 and a common line 24 adjacent to the second thin film transistor 27 through two second thin film transistors 27. Specifically, in the present embodiment, each common electrode 25 is located in two adjacent pixel cells P between two sets of data lines 22 in the scanning line 21 direction. In one embodiment, each of the common electrodes 25 may also be connected to the scan line 21 and the common line 24 adjacent to the second thin film transistor 27 through a second thin film transistor 27.
For other structures and operation principles of this embodiment, reference may be made to the first embodiment, which is not described herein again.
[ fourth embodiment ]
Referring to fig. 12 and 13, a liquid crystal display device according to a fourth embodiment of the present invention is different from the first embodiment in that a liquid crystal layer 40 in the present embodiment uses negative liquid crystal molecules. With the technical progress, the performance of the negative liquid crystal is remarkably improved, and the application is more and more extensive. In the present embodiment, as shown in fig. 12, in the initial state (i.e., the liquid crystal display device is not applied with any voltage), the negative liquid crystal molecules in the liquid crystal layer 40 have a large initial pretilt angle with respect to the substrates 20 and 30, i.e., the negative liquid crystal molecules are in an inclined posture with respect to the substrates 20 and 30 in the initial state.
Narrow view angle mode: referring to fig. 12, in the embodiment, in the narrow viewing angle mode, a reference voltage is applied to the upper electrodes 33 of the color filter substrate 30, a first common voltage Vcom1 with a smaller amplitude is applied to the common lines 24 located at odd-numbered positions in the direction of the scan lines 21 on the array substrate 20 through the first signal lines 28a, and a second common voltage Vcom2 with a smaller amplitude is applied to the common lines 24 located at even-numbered positions in the direction of the scan lines 21 on the array substrate 20 through the second signal lines 28b, so that voltage differences between all the common electrodes 25 and the upper electrodes 33 are smaller than a first preset value (e.g., smaller than 1V). At this time, since the voltage difference between all the common electrodes 25 and the upper electrodes 33 is small, the tilt angle of the liquid crystal molecules in the liquid crystal layer 40 is almost unchanged and remains in a tilted posture, so that the liquid crystal display device has large-angle viewing light leakage, the contrast ratio is reduced in the oblique viewing direction, and the viewing angle is narrowed, and at this time, the liquid crystal display device realizes narrow viewing angle display.
In this embodiment, in the narrow viewing angle mode, the reference voltage applied by the upper electrode 33 may be a constant 0V, and the common voltages Vcom1, Vcom2 applied through the first signal line 28a and the second signal line 28b may also be a constant 0V, so that the common voltage applied to each common electrode 25 is the same as the reference voltage, and the voltage difference between each common electrode 25 and the upper electrode 33 is zero, thereby achieving a better narrow viewing angle effect.
Wide view angle mode: referring to fig. 13, in the embodiment, in the wide viewing angle mode, a reference voltage is applied to the upper electrode 33 of the color filter substrate 30, a first common voltage Vcom1 with a larger amplitude is applied to the odd-numbered common lines 24 on the array substrate 20 in the direction of the scan lines 21 through the first signal line 28a, and a second common voltage Vcom2 with a larger amplitude is applied to the even-numbered common lines 24 on the array substrate 20 in the direction of the scan lines 21 through the second signal line 28b, so that voltage differences between all the common electrodes 25 and the upper electrode 33 are greater than a second preset value (e.g., greater than 1.5V), where the second preset value is greater than or equal to the first preset value. At this time, because the voltage difference between all the common electrodes 25 and the upper electrodes 33 is large, a strong vertical electric field E (as shown by an arrow in fig. 13) is generated in the liquid crystal cell between the array substrate 20 and the color film substrate 30, and because the negative liquid crystal molecules are deflected in the direction perpendicular to the electric field lines under the action of the electric field, the negative liquid crystal molecules are deflected under the action of the vertical electric field E, so that the tilt angle between the liquid crystal molecules and the substrates 20 and 30 is reduced, the light leakage phenomenon of the liquid crystal display device at an oblique angle is correspondingly reduced, the contrast is improved and the viewing angle is increased in the oblique viewing direction, and the liquid crystal display device finally realizes wide viewing angle display.
In this embodiment, in the wide viewing angle mode, the reference voltage applied by the upper electrode 33 may be a constant 0V, and the magnitudes of the first common voltage Vcom1 and the second common voltage Vcom2 applied to each common electrode 25 may be selected to be greater than 3V (i.e., | Vcom1| ≧ 3V, | Vcom2| ≧ 3V), so that the voltage difference between each common electrode 25 and the upper electrode 33 is greater than 3V, and a good wide viewing angle effect can be achieved.
For other structures of this embodiment, reference may be made to the first embodiment, which is not described herein again.
Referring to fig. 14a and 14b, the lcd device further has a viewing angle switch button 80 for switching different viewing angle modes of the lcd device. The view angle switching key 80 may be a mechanical key (as shown in fig. 14a) or a virtual key (as shown in fig. 14b, set by software control or application program). When a user needs to switch the wide and narrow viewing angles, a viewing angle switching request can be sent to the liquid crystal display device by operating the viewing angle switching key 80, and finally the driving circuit 60 controls voltage signals applied to the upper electrode 33 of the color film substrate 30 and the common electrodes 25 of the array substrate 20, so that the wide and narrow viewing angles can be switched, and the user can freely select and switch the wide and narrow viewing angles according to different peep-proof requirements.
Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.