TWI381356B - Liquid crystal display and driving method therefor - Google Patents

Description

Liquid crystal display device and driving method thereof

The present invention relates to a liquid crystal display device and a method of driving the same.

Due to its low radiation, overall thinness and low power consumption, liquid crystal display devices are widely used in mobile phones, personal digital assistants, notebook computers, personal computers and televisions. With the maturity and innovation of related technologies, Its variety is growing.

The liquid crystal display device can be classified into a transmissive liquid crystal display device and a reflective liquid crystal display device depending on the light source used in the liquid crystal display device. The transmissive liquid crystal display device needs to set a backlight on the back of the liquid crystal display panel to realize image display. However, the energy consumption of the backlight accounts for about half of the energy consumption of the entire transmissive liquid crystal display device, so the transmissive liquid crystal display device The energy consumption is large. The reflective liquid crystal display device can solve the problem of large energy consumption of the transmissive liquid crystal display device, but it is difficult to realize image display in a weak light environment. The transflective liquid crystal display device can solve the above problems.

Please refer to FIG. 1 , which is a schematic side view of a prior art transflective liquid crystal display device. The transflective liquid crystal display device 1 includes a liquid crystal display panel 10 and a backlight module 15 which are stacked one on another.

The liquid crystal display panel 10 includes a first substrate 11 , a second substrate 12 , and a liquid crystal layer 13 sandwiched between the first substrate 11 and the second substrate 12 .

A color filter 114, a common electrode 113 and a first alignment film 116 are sequentially stacked on the surface of the first substrate 11 adjacent to the liquid crystal layer 13 side. The color filter 114 is adjacent to the first substrate 11 and includes a plurality of red, green, and blue color filters (not labeled). A first retarder 111 and a first polarizer 112 are sequentially stacked on the first substrate 11 away from the surface of the liquid crystal layer 13 , wherein the first retarder 111 is adjacent to the second substrate 12 .

A transparent electrode 123, a passivation layer 124, a reflective electrode 125 and a second alignment film 126 are sequentially stacked on the surface of the second substrate 12 adjacent to the liquid crystal layer 13 . The transparent electrode 123 is adjacent to the second substrate 12 . The passivation layer 124 and the reflective electrode 125 have a plurality of openings 131 to allow light to pass through the opening 131. A second retarder 121 and a second polarizer 122 are sequentially stacked on the surface of the second substrate 12 away from the liquid crystal layer 13 .

The first and second retardation plates 111 and 121 are quarter-wave plates (λ/4). The first and second alignment films 116 and 126 are Homogeneous Alignment. The polarization directions of the first polarizer 112 and the second polarizer 122 are perpendicular to each other. The liquid crystal layer 13 has a different thickness, wherein a region corresponding to the liquid crystal layer 13 sandwiched between the common electrode 113 and the reflective electrode 125 is a reflective region corresponding to the sandwich between the common electrode 113 and the opening 131. The area of the liquid crystal layer 13 is a penetration area.

Each of the color filter corresponding regions of the color filter 114 is defined as a sub-pixel (not labeled), and each sub-pixel correspondingly includes a penetrating region and a reflecting region. One of the adjacent settings is a red sub-pixel, a green sub-pixel, and a blue sub-pixel, which are defined as a single pixel unit.

The backlight module 15 generates a white planar light source, and the emitted white planar light beam illuminates the liquid crystal display panel 10 to display a picture.

When the screen is displayed by the liquid crystal display device 1, first, the data signal corresponding to each sub-pixel is input to the liquid crystal display panel 10 during each frame time to control the throughput of the light. Then, by the filtering action of the color filter 114, a monochromatic light is obtained for each sub-pixel, so that each sub-pixel exhibits one of three colors of red, green, and blue, respectively. Finally, the use of human visual resolution and spatial color mixing principle to achieve color display.

When the ambient light is strong, the liquid crystal display device 1 turns off the backlight, and the reflective area reflects the ambient light to perform image display.

However, each pixel unit of the transflective liquid crystal display device 1 includes spatially arranged red, green, and blue sub-pixels, which occupy a large space and have a low resolution, and are often used when displaying a fine picture. Defects such as zigzag appear. Secondly, the color filter 114 has a complicated process and a high cost. When the ambient light is used for display, due to the filtering effect of the color filter 114, when the ambient light enters and reflects the liquid crystal display panel 10, the double filter effect of the color filter 114 affects the intensity. A great attenuation is obtained, so that the utilization ratio of the ambient light to the liquid crystal display device 1 is low.

In view of this, it is necessary to provide a transflective liquid crystal display device with high resolution and low cost.

It is also necessary to provide a driving method of a transflective liquid crystal display device.

A liquid crystal display device comprising a transflective liquid crystal display panel and a backlight module capable of providing a plurality of monochromatic lights for the transflective liquid crystal display panel, the transflective liquid crystal display panel The transflective liquid crystal display panel and the backlight module cooperate with the sequential color mixing driving method to display a color picture when the backlight module is turned on, and the backlight module is displayed when the backlight module is turned on. When turned off, the transflective liquid crystal display panel reflects ambient light through the reflective area to display a gray scale picture.

A driving method of a liquid crystal display device, wherein the liquid crystal display device comprises a transflective liquid crystal display panel and a backlight module for providing illumination for the transflective liquid crystal display panel, the transflective The liquid crystal display panel comprises a plurality of spaced-apart penetration regions and a reflection region, and the backlight module is capable of emitting a plurality of monochromatic lights. The driving method comprises: a. when the backlight module is in an on state, each frame is divided into The plurality of consecutive sub-periods, the backlight module provides a monochromatic light in any one of the sub-periods, and the liquid crystal display device displays a monochrome sub-picture.

b. When the backlight module is in the off state, each frame is a time period during which the transflective liquid crystal display panel uses the reflective area to reflect ambient light to display a frame of picture.

A driving method of a liquid crystal display device, wherein the liquid crystal display device comprises a transflective liquid crystal display panel and a backlight module for providing illumination for the transflective liquid crystal display panel, the transflective The liquid crystal display panel includes a plurality of spaced apart penetration regions and a reflective region, and the backlight module is capable of emitting red light, green light, and blue light. The driving method includes: c. when the backlight module is in an open state, each The frame time period is divided into three sub-picture time periods, and the red sub-picture data is input into the transflective liquid crystal display panel in the first sub-picture time period, and the backlight module emits red light; During the second sub-picture period, the green sub-picture data is input into the transflective liquid crystal display panel, and the backlight module emits green light; in the third sub-picture time period, the blue sub-picture data is input. The transflective liquid crystal display panel emits blue light.

d. When the backlight module is in the off state, the frame data of the frame picture is input into the transflective liquid crystal display panel during the frame time period of each frame, and the transflective liquid crystal display panel reflects The ambient light is used to display the picture.

Compared with the prior art, in the liquid crystal display device of the present invention, the liquid crystal display panel is a transflective liquid crystal display panel, and the backlight module can emit a plurality of monochromatic lights. When the liquid crystal display device operates in the penetrating mode, it adopts a driving method of sequential color mixing to achieve higher resolution. Since the driving method of the time-series color mixing is employed, the arrangement of the color filters is omitted, thereby reducing the production cost and improving the light-emitting brightness of the liquid crystal display device. Further, the liquid crystal display device is in a reflective operation mode, and the driving method thereof is simple, and the utilization of external light is high, which is beneficial to reducing energy consumption.

Please refer to FIG. 2 , which is a partial structural view of a side surface of a liquid crystal display device of the present invention. The liquid crystal display device 2 includes a liquid crystal display panel 20 and a backlight module 25 adjacent to the liquid crystal display panel 20 and providing planar light thereto.

The liquid crystal display panel 20 is a transflective liquid crystal display panel, which comprises a first substrate 21, a second substrate 22, and a sandwich between the first substrate 21 and the second substrate 22. Liquid crystal layer 23.

The liquid crystal display panel 20 includes a plurality of spaced-apart regions (not labeled) and a reflective region (not labeled), and the liquid crystal layer 23 is an optically compensated bend-aligned structure (OCB), wherein the penetrating region is The thickness of the liquid crystal layer 23 is greater than the thickness of the liquid crystal layer 23 of the reflective region, and a penetration region and a reflective region are defined adjacent to each other as a pixel unit.

A common electrode 216 and a first alignment film 218 are disposed between the first substrate 21 and the liquid crystal layer 23, wherein the common electrode 216 is adjacent to the first substrate 21. A first optical compensation film 214, a first phase retarder 213 and a first polarizer 212 are sequentially stacked on the surface of the first substrate 21 away from the liquid crystal layer 23, wherein the first optical compensation film 214 is adjacent to the first optical compensation film 214. The first substrate 21.

A penetrating electrode 226 and a second alignment film 228 are sequentially disposed between the second substrate 22 and the liquid crystal layer 23 in each of the penetrating regions. A passivation layer 229, a reflective electrode 227 and a second alignment film 228 are sequentially stacked between the second substrate 22 and the liquid crystal layer 23 in each of the reflective regions. A second optical compensation film 224, a second phase retarder 223 and a second polarizer 222 are sequentially stacked on the surface of the second substrate 22 away from the liquid crystal layer 23, wherein the second optical compensation film 224 is adjacent to the second optical compensation film 224. The second substrate 22 is.

The first alignment film 218 and the second alignment film 228 are horizontally aligned and parallel to each other. The liquid crystal molecules of the liquid crystal layer 23 adjacent to the first and second alignment films 218 and 228 have a pretilt angle of 0° to 15°. The first phase retarder 213 and the second phase retarder 223 may be a Uniaxial Retardation Film, a Biaxial Retardation Film, or a Hybrid-Crystal. . The absorption axis of the first polarizer 212 and the rubbing direction of the first alignment film 218 are 0°, and the absorption axis of the second polarizer 222 and the first polarizer 212 The angle of the absorption axis is 90°. The angle between the slow axis of the first phase retarder 213 and the absorption axis of the first polarizer 212 is 45°, and the slow axis of the second phase retarder 223 and the slow axis of the first phase retarder 213 are perpendicular to each other.

The backlight module 25 is an edge-lit backlight module, and includes a light guide plate 251, an optical film group 252, and a plurality of light sources 253. The plurality of light sources 253 are disposed on the side of the light guide plate 251, and are capable of emitting at least monochromatic light such as red light, green light, and blue light, which may be a plurality of cold cathode fluorescent lamps (CCFLs) or a plurality of single colors. Light Emitting Diode (LED). The optical film group 252 is disposed between the liquid crystal display panel 20 and the light guide plate 251.

The monochromatic light emitted by the complex light source 253 is guided by the light guide plate 251 to form a monochromatic surface light source. The light beam generated by the surface light source passes through the optical film group 252 and is transmitted to the liquid crystal display panel 20. Wherein, the optical film 252 makes the light intensity distribution of the surface light source more uniform, and the traveling direction of the light beam is more concentrated.

The display driving method of the liquid crystal display device 2 is as follows: when the environment of the liquid crystal display device 2 is dark, the driving signal is applied to drive the backlight module 25 to operate, and the color display is realized by the method of sequential color mixing. That is, the liquid crystal display device 2 operates in the penetrating mode, and the specific driving method thereof is described in conjunction with FIG. 3: first, each frame of the picture is chronologically divided into a red sub-picture, a green sub-picture, and a blue sub-picture. . In FIG. 3, curves R _data , G _data , and B _data respectively represent data voltage driving waveforms of a red sub-picture, a green sub-picture, and a blue sub-picture; and curves R _light , G _light , and B _light respectively represent the backlight module 25 . A driving wave pattern that emits red, green, and blue monochromatic light.

After the "t1" time period, the data voltage R _{data of the} red sub-picture is first applied to the liquid crystal display panel 20. After the liquid crystal molecules respond to the rotation, the backlight module 25 is controlled to emit a red backlight R _{light to} illuminate the The liquid crystal display panel 20, at this time, the liquid crystal display panel 20 displays a red sub-picture.

b. The data voltage G _{data of the} green sub-picture is applied to the liquid crystal display panel 20 during the "t2" time period, and after the liquid crystal molecules respond to the rotation, the backlight module 25 is controlled to emit a green backlight G _{light to} illuminate the liquid crystal. The display panel 20 is displayed at this time, and the liquid crystal display panel 20 displays a green sub-picture.

c. During the “t3” time period, the data voltage B _{data of the} blue sub-picture is applied to the liquid crystal display panel 20. After the liquid crystal molecules respond to the rotation, the backlight module 25 is controlled to emit a blue backlight B _{light to} illuminate. The liquid crystal display panel 20, at this time, the liquid crystal display panel 20 displays a blue sub-picture.

According to the visual persistence effect of the human eye, when the duration of each frame sub-picture is short, such as 5.56 ms, the image seen by the observer is a picture formed by the mixed color of the red, green and blue monochrome sub-pictures, that is, one Frame full color picture.

In the next frame display, steps a-c are repeated to refresh the color display screen.

When the environment of the liquid crystal display device 2 is bright, it applies a driving signal to turn off the backlight module 25, and performs image display using ambient light, that is, the liquid crystal display device 2 operates in a reflective mode. Since the liquid crystal display panel 20 omits the use of the color filter, only the gradation display can be performed in the reflective mode operation, and the color display cannot be performed. Therefore, when the liquid crystal display device 2 is completely displayed by the external light, the image is displayed in black and white. Therefore, in the display driving process, it is not necessary to divide each frame of the picture into a plurality of sub-pictures, and it is only necessary to apply the gradation voltage required for each frame of the picture to the liquid crystal display panel 20. When the ambient light passes through the first substrate 21 and is irradiated to the reflective electrode 227 of the second substrate 22, and then reflected by the reflective electrode 227, the liquid crystal display panel 20 is emitted. Since the liquid crystal layer 23 has the function of a light valve under the control of the data voltage, by controlling the rotation of the liquid crystal layer 23, each pixel unit displays a corresponding gray scale, thereby displaying a monochrome black and white picture as a whole. .

The liquid crystal display device 2 adopts a liquid crystal display panel 20 with a transflective structure and a backlight module 25 with a plurality of monochromatic light functions, and at the same time, a driving method for timing mixed color has the following advantages: first, each minimum pixel is Color display can be completed for higher resolution. Next, since the liquid crystal display device 2 is driven by the time-mixing method, the color filter is omitted, thereby simplifying the process and reducing the production cost. Further, the liquid crystal display panel 20 can improve the utilization of the backlight and reduce the energy consumption by the filtering effect of the achromatic filter. At the same time, when the external ambient light is used for image display, the double filtering of the external light entering and leaving the liquid crystal display panel 20 is avoided, and the high light intensity can be maintained, thereby improving the utilization ratio of the reflective electrode 227 to the external ambient light, that is, the liquid crystal. The display device 2 can display the external ambient light even under weak ambient light, thereby increasing the range of application of the liquid crystal display device 2.

Please refer to FIG. 4 , which is a partial side structural view of a second embodiment of the liquid crystal display device of the present invention. The liquid crystal display panel 30 is substantially the same as the liquid crystal display panel 20 of the first embodiment. The main difference is that the liquid crystal display panel 30 further includes a first phase retarder 313 and a first polarizer 312. The third phase retarder 311 is a fourth phase retarder 321 disposed between a second phase retarder 323 and a second polarizer 322. The first and second phase retarders 313 and 323 are quarter-wave plates, and the third and fourth phase retarders 311 and 321 are half-wave plates.

The angle between the slow axis of the third phase retarder 311 and the absorption axis of the first polarizer 312 is 10°-20°, and the slow axis of the fourth phase retarder 321 and the absorption of the second polarizer 322 The angle between the axes is 10°~20°. The angle between the slow axis of the third phase retarder 311 and the slow axis of the first phase retarder 313 is 55° to 65°, and the slow axis of the fourth phase retarder 321 is slower than the second phase retarder 323. The angle between the axes is 55°~65°.

The third phase retarder 311 and the fourth phase retarder 321 can further compensate the linearly polarized light to be circularly polarized, thereby further improving the utilization of light.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above-mentioned embodiments are merely preferred embodiments of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and equivalent modifications or variations made by those skilled in the art in light of the spirit of the present invention are It should be covered by the following patent application.

Liquid crystal display device. . . 2

LCD panel. . . 20, 30

First substrate. . . twenty one

First polarizer. . . 212, 312

Phase retarder. . . 213, 313

First optical compensation film. . . 214

Common electrode. . . 216

First alignment film. . . 218

Second substrate. . . twenty two

Second polarizer. . . 222,322

Second phase retarder. . . 223, 323

Penetrating the electrode. . . 226

Reflective electrode. . . 227

Second alignment film. . . 228

Passivation layer. . . 229

Liquid crystal layer. . . twenty three

Backlight module. . . 25

Light guide plate. . . 251

Optical film set. . . 252

light source. . . 253

Third phase retarder. . . 311

Fourth phase retarder. . . 321

Second optical compensation film. . . 224

1 is a schematic side view showing a side view of a prior art transflective liquid crystal display device.

2 is a schematic view showing the structure of a side surface of a liquid crystal display device of the present invention.

3 is a schematic view showing a driving method of the liquid crystal display device shown in FIG. 2 operating in a penetration mode.

4 is a partial side view showing the second embodiment of the liquid crystal display device of the present invention.

Liquid crystal display device. . . 2

LCD panel. . . 20

First substrate. . . twenty one

First polarizer. . . 212

Phase retarder. . . 213

First optical compensation film. . . 214

Common electrode. . . 216

First alignment film. . . 218

Second substrate. . . twenty two

Second polarizer. . . 222

Second phase retarder. . . 223

Second optical compensation film. . . 224

Penetrating the electrode. . . 226

Reflective electrode. . . 227

Second alignment film. . . 228

Passivation layer. . . 229

Liquid crystal layer. . . twenty three

Backlight module. . . 25

Light guide plate. . . 251

Optical film set. . . 252

light source. . . 253

Claims (19)

A liquid crystal display device comprising a transflective liquid crystal display panel and a backlight module capable of providing a plurality of monochromatic lights for the transflective liquid crystal display panel, the transflective liquid crystal display panel The method includes a first substrate, a second substrate, a liquid crystal layer sandwiched between the two substrates, a first polarizer, a second polarizer, and a first polarizer and the first a first phase retarder between the substrates, a second phase retarder disposed between the second polarizer and the second substrate, and a first phase retarder disposed between the first polarizer and the first phase retarder a third phase retarder, a fourth phase retarder disposed between the second polarizer and the second phase retarder, and a plurality of spaced-apart penetration regions and a reflective region, wherein the first polarizer is disposed on the The first substrate is away from the surface of the liquid crystal layer, and the second polarizer is disposed on a surface of the second substrate away from the liquid crystal layer. When the backlight module is turned on, the transflective liquid crystal display panel And when the backlight module is mated Dither drive method, a display color images, the backlight module when closed, the transflective type liquid crystal display panel, ambient light reflected by the reflective display area gray scale pictures. The liquid crystal display device of claim 1, wherein the second substrate is provided with a plurality of penetrating electrodes and a plurality of reflective electrodes spaced apart from a surface of the liquid crystal layer. The liquid crystal display device of claim 2, wherein the transflective liquid crystal display panel further comprises a first alignment film disposed between the first substrate and the liquid crystal layer, and a first alignment film disposed thereon First a second alignment film between the second substrate and the liquid crystal layer, the first alignment film and the second alignment film are horizontally aligned and parallel to each other, and the liquid crystal layer is adjacent to the pretilt angle of the liquid crystal molecules of the first and second alignment films 0 ° ~ 15 °. The liquid crystal display device of claim 1, wherein an angle between a slow axis of the third phase retarder and an absorption axis of the first polarizer is 10° to 20°, and the fourth phase retarder is slow. The angle between the shaft and the absorption axis of the second polarizer is 10°-20°. The liquid crystal display device of claim 1, wherein an angle between a slow axis of the third phase retarder and a slow axis of the first phase retarder is 55° to 65°, and the fourth phase retarder The angle between the slow axis and the slow axis of the second phase retarder is 55°~65°. The liquid crystal display device of claim 1, wherein the backlight module comprises a plurality of light sources capable of emitting at least red light, green light, and blue light. The liquid crystal display device of claim 6, wherein the plurality of light sources are a plurality of cold cathode ray tubes or monochromatic light emitting diodes. A driving method of a liquid crystal display device, wherein the liquid crystal display device comprises a transflective liquid crystal display panel and a backlight module for providing illumination for the transflective liquid crystal display panel, the transflective The liquid crystal display panel comprises a first substrate, a second substrate, a liquid crystal layer sandwiched between the two substrates, a first polarizer, a second polarizer, and a first polarizer. a first phase retarder between the first substrate, a second phase retarder disposed between the second polarizer and the second substrate, and a first polarizer disposed on the first polarizer a third phase retarder between the chip and the first phase retarder, a fourth phase retarder disposed between the second polarizer and the second phase retarder, and a plurality of spaced apart penetration regions and a reflective layer, the first polarizer is disposed on a surface of the first substrate away from the liquid crystal layer, and the second polarizer is disposed on a surface of the second substrate away from the liquid crystal layer, the backlight module capable of emitting a plurality of Monochromatic light, the driving method comprises: a. when the backlight module is in an on state, each frame is divided into a plurality of consecutive sub-periods, and the backlight module provides a monochromatic light in any sub-period of time The liquid crystal display device displays a monochrome sub-picture; b. when the backlight module is in a closed state, each frame is a time period during which the transflective liquid crystal display panel utilizes the The reflection area reflects the ambient light and displays a frame of picture. The driving method of the liquid crystal display device according to claim 8, wherein the backlight module comprises a plurality of light sources, and the plurality of light sources can emit at least red light, green light and blue light. The method for driving a liquid crystal display device according to claim 9, wherein when the backlight module is in an on state, each frame is divided into three consecutive sub-periods, and in the three sub-periods, The light source respectively emits red light, green light and blue light, and the transflective liquid crystal display panel correspondingly displays a red sub-picture, a green sub-picture and a blue sub-picture. The method for driving a liquid crystal display device according to claim 9, wherein when the backlight module is in an on state, each frame is divided into three consecutive sub-periods, and in each sub-period, first Inputting a sub-picture data into the transflective liquid crystal display panel, and then the backlight The module emits one of red light, green light and blue light, and the monochromatic light emitted by the backlight module is different during the three sub-time periods. The driving method of the liquid crystal display device according to claim 10, wherein each sub-period is 5.56 ms. The method for driving a liquid crystal display device according to claim 8, wherein when the backlight module is in a closed state, the gray scale is input in the transflective liquid crystal display panel in each frame time. data. The method for driving a liquid crystal display device according to claim 8, wherein the second substrate is provided with a plurality of penetrating electrodes and a plurality of reflective electrodes spaced apart from a surface of the liquid crystal layer. The method for driving a liquid crystal display device according to claim 14, wherein the transflective liquid crystal display panel further comprises a first alignment film disposed between the first substrate and the liquid crystal layer, and a a second alignment film disposed between the second substrate and the liquid crystal layer. A driving method of a liquid crystal display device, wherein the liquid crystal display device comprises a transflective liquid crystal display panel and a backlight module for providing illumination for the transflective liquid crystal display panel, the transflective The liquid crystal display panel comprises a first substrate, a second substrate, a liquid crystal layer sandwiched between the two substrates, a first polarizer, a second polarizer, and a first polarizer. a first phase retarder between the first substrate and a second phase retarder disposed between the second polarizer and the second substrate, a first polarizer disposed on the first polarizer and the first phase retarder a third phase retarder between the sheets, one disposed between the second polarizer and the second phase retarder a fourth phase retarder, and a plurality of spaced apart regions and a reflective region, wherein the first polarizer is disposed on a surface of the first substrate away from the liquid crystal layer, and the second polarizer is disposed on the second substrate The backlight module is capable of emitting red light, green light, and blue light on the surface of the liquid crystal layer. The driving method includes: c. when the backlight module is in an open state, dividing each frame time period into three During the first sub-picture period, the red sub-picture data is input into the transflective liquid crystal display panel, and the backlight module emits red light; during the second sub-picture period, Inputting the green sub-picture data into the transflective liquid crystal display panel, the backlight module emitting green light; and inputting the blue sub-picture data into the transflective liquid crystal during the third sub-picture period a display panel, the backlight module emits blue light; d. when the backlight module is in a closed state, the frame data of the frame image is input into the transflective liquid crystal display panel in each frame time period. The The transflective liquid crystal display panel reflects ambient light to display a picture. The driving method of the liquid crystal display device according to claim 16, wherein each sub-picture period is 5.56 ms. The driving method of the liquid crystal display device of claim 16, wherein the second substrate is provided with a plurality of penetrating electrodes and a plurality of reflecting electrodes spaced apart from a surface of the liquid crystal layer. The method for driving a liquid crystal display device according to claim 18, wherein the transflective liquid crystal display panel liquid crystal display surface The board further includes a common electrode disposed between the first substrate and the first alignment film.