JPH08201777A - Liquid crystal display - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object of the present invention to improve the gray scale display performance of an active matrix liquid crystal display device, particularly when observed from the main viewing angle direction. A liquid crystal is sandwiched between two substrates, pixels are arranged in a matrix on a plane of the substrates, the pixels are formed by a plurality of sub-pixels, and each liquid crystal layer constituting the plurality of sub-pixels. And a means for applying different voltages to each other, and an inclination angle of 0 ° from the vertical line of the substrate along the long axis direction of the liquid crystal molecules positioned in the middle of the liquid crystal layer when no voltage is applied.
The display area ratio of the plurality of sub-pixels of the pixel and the driving voltage difference of the light amount-signal voltage characteristic of each sub-pixel are set so that the light amount-signal voltage characteristic at 40 ° monotonically decreases.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for improving the viewing angle characteristics of a liquid crystal display device.

[0002]

2. Description of the Related Art First, the structure of a liquid crystal display device driven by a conventional thin film transistor (called TFT) array substrate will be described with reference to FIGS. FIG. 11A shows a TFT
FIG. 11B is a plan configuration diagram of the liquid crystal display device.
FIG. 12A is a sectional view taken along the line aa ′ and bb ′ in FIG. 12A and seen from the lateral direction. FIG. 12 is an equivalent circuit diagram of one pixel of the TFT liquid crystal display device.

In the manufacturing method, first, the transparent electrode 2 for driving the liquid crystal of the pixel 12 is formed on the transparent glass substrate 1a.
Next, a silicon oxide film 3 is deposited as an insulator. Then, the gate electrode 4 is formed of a metal such as chromium. Then, a silicon nitride film 5 that functions as a gate insulating film of the TFT 15 is deposited thereon. Next, the semiconductor layer 6 forming the TFT 15 is formed. The resistance value of the semiconductor layer 6 changes according to the voltage applied to the gate electrode 4, and provides the function as a switch element. Next, contact holes 7a and 7b are opened in the insulating film layers of the silicon oxide film 3 and the silicon nitride film 5 on the transparent electrode 2 to expose a part of the transparent electrode 2. Next, using a metal such as aluminum,
Source electrode 8a, drain electrode 8b, additional capacitance electrode 8c
Are formed at the same time. At this time, the drain electrode 8b passes through the contact hole 7a opened on the transparent electrode 2,
The drain electrode 8b and the transparent electrode 2 are formed so as to be connected, and similarly, the additional capacitance electrode 8c and the transparent electrode 2 are formed so as to be connected through the contact hole 7b. Also,
An additional capacitance 14 is formed between the additional capacitance electrode 8c and the preceding gate electrode 4 ', and the additional capacitance 14 is arranged in parallel with the pixel 12. Through the above steps, TF
The T array substrate is completed. After that, this substrate is bonded to another substrate 1b on which a black stripe 9 is partially formed and a transparent electrode 10 is deposited on one surface with a gap of about 5 μm formed, and a liquid crystal 11 is injected therebetween. Then, a polarizing plate is arranged on the outer side of each of the two substrates.

Next, a driving method of a conventional TFT liquid crystal display device will be described with reference to FIG. The TFT 15 functions as a switch element, and the pulse signal V (G) input to the gate electrode 4 turns on the TFT 15 on the gate electrode 4. Then, the signal V (S) supplied to the source electrode 8a is supplied to the pixel 12 via the TFT 15 in the ON state. A constant voltage V (Com) is applied to the transparent electrode 10 on the other substrate 1b. As a result, an arbitrary voltage Vlc is applied between the pixel 12 and the transparent electrode 10, the arrangement state of the intervening liquid crystal molecules 11 is changed depending on the magnitude of the voltage, and the polarization direction of light passing through this liquid crystal layer is changed. Change. Polarizing plates are arranged on the outer sides of the two substrates. Here, a case will be described in which the polarization axes of the two polarizing plates are set so that the angle formed between them is approximately 90 degrees. As a result, when a voltage is not applied to the liquid crystal layer, a bright state is displayed, and when a voltage is applied, a dark state is displayed (the display mode with such a polarizing plate layout is called a normally white mode). ).

[0005]

First, the conventional T
The viewing angle characteristics of the FT-LCD will be described. Figure 14
In the conventional normally white mode TFT liquid crystal display device, the luminance characteristics with respect to the drive voltage of the liquid crystal display device are shown. FIG. 14A shows the luminance characteristics with respect to the driving voltage when viewed from the front (θ = 0 °) of the liquid crystal display device, and FIG. 14B shows the liquid crystal display device in the downward direction (θ>
The luminance characteristics with respect to the drive voltage when the viewpoint is tilted at 0 °, which is referred to as the main viewing angle direction) are shown.

As used herein, "downward" means that liquid crystal is sandwiched between two transparent glass substrates 1a and 1b as shown in the lower diagram of FIG. When the directions 21a and 21b are in the directions of the arrows, the following figure is cut along the aa 'plane and seen from the lateral direction (when a voltage is applied between two substrates and liquid crystal molecules rise). , Which is defined as when the viewpoint is tilted to the right. Further, the visual angle in the present invention indicates the angle of inclination of the viewpoint from the vertical line of the substrate.

As shown in FIG. 14 (a), when displaying 8 gradations in a conventional liquid crystal display device, first, the luminance is divided into eight equal parts (B1, B2, ..., B) when viewed from the front (0 °).
8) and the voltage level (V
1, V2, ..., V8) are set. On the other hand, when the viewpoint is tilted in the main viewing angle direction, as shown in FIG.
The drive voltage curve shifts to the low drive voltage side as compared with the case of θ = 0 °, and a new peak appears on the high drive voltage side. Looking at the brightness levels (B1 ', B2', ..., B8 ') for each voltage level in this state, B6'
The brightness levels of B7 'and B7' are reversed by a new peak appearing on the high voltage side. This is called a gradation inversion phenomenon, and it looks like a negative image of a photograph by visual observation. Further, in the high brightness portion (between B1 'and B2', etc.), the difference between the brightness levels becomes large, while in the low brightness portion, the difference between the brightness levels becomes small. This is visually seen as a very dark image compared to the image seen from the front (called a blackout phenomenon). As described above, in the conventional liquid crystal display device, there is a problem that gradation display is considerably deteriorated when the viewpoint is tilted in the main viewing angle direction.

The present invention has been made to solve the above problems, and an object of the present invention is to improve the gradation display performance of an active matrix type liquid crystal display device, particularly when observed from the main viewing angle direction.

[0009]

In order to solve the above problems, the present invention provides a normally white mode liquid crystal display device in which liquid crystal is sandwiched between two substrates and pixels are arranged on a plane of the substrates. Arranged in a line, the pixels are formed of a plurality of sub-pixels, and means for applying different voltages to the respective liquid crystal layers forming the plurality of sub-pixels are provided. Display of each sub-pixel so that the luminance-voltage characteristic along the long axis direction of the liquid crystal molecule positioned in the middle of the substrate at a tilt angle of 0 ° to 40 ° from the vertical line of the substrate monotonically decreases or monotonically increases. It is characterized by optimizing the area ratio and the drive voltage difference of each sub-pixel.

[0010]

With the above structure, the sub-pixel 1 has the same characteristic as the conventional one, but the sub-pixel 2 has an arbitrary means as shown in FIG. By applying a low voltage to the liquid crystal layer by using, the characteristics are shifted to the high signal voltage (high drive voltage) side with respect to the sub-pixel 1 by an arbitrary voltage. Further, the light amount of each sub-pixel is controlled by setting the display area ratio of each sub-pixel to an arbitrary value. And the light quantity of one pixel is
It is the sum of the light amounts of two sub-pixels. here,
In each sub-pixel, there is a peak that causes a gradation inversion phenomenon on the high signal voltage side. However, the characteristic of one pixel obtained by adding these is a smooth curve that monotonically decreases because the peaks of the sub-pixels cancel each other. This eliminates the conventionally observed gradation inversion phenomenon. Further, the light amount-signal voltage curve for one pixel has a gentler slope than the conventional one. As described above, the light amount-signal voltage curve is shifted to the low signal voltage (low drive voltage) side by inclining the viewpoint in the main viewing angle direction. Since this voltage shift amount is the same as that in the conventional configuration, the difference in the light amount between the levels of the present invention is more uniform than that in the conventional configuration when gradation display is performed. This alleviates the blackout phenomenon conventionally observed. As described above, in the present invention, the display performance is significantly improved in the viewing angle in the main viewing angle direction as compared with the conventional one.

By the way, the one disclosed in Japanese Patent Application Laid-Open No. 2-12 utilizes white and black levels independent of the viewing angle.
A plurality of sub-pixels forming a pixel are driven at two levels of white and black, and gradation display (gray level display) independent of the viewing angle is performed depending on the number of sub-pixels displaying white or black. . On the other hand, according to the present invention, 2
By setting one or more sub-pixels to have appropriate drive voltage differences and display area ratios, mainly the light intensity-signal voltage characteristics in the lower viewing angle direction are improved and the gradation display performance is improved. The configuration is different from that of the publication.

[0012]

EXAMPLE A first example will be described with reference to FIGS.
FIG. 1 shows a TFT observed from the front in the first embodiment.
5 is a light amount-signal voltage characteristic of each pixel of the liquid crystal display device. FIG. 2 shows the light amount-signal voltage characteristics of each pixel of the TFT liquid crystal display device observed from the lower viewing angle θ = 40 °. FIG. 3 (a)
Is a plan view of a TFT liquid crystal display device, and FIG.
In FIG. 3A, a cross-sectional configuration view taken along the line aa ′ and viewed from the lateral direction, and FIG. 4 are equivalent circuit diagrams of one pixel of the TFT liquid crystal display device. FIG. 5 shows the light quantity-signal voltage characteristics of the TFT liquid crystal display device observed in the range of the lower viewing angle θ = 0 to 60 °. FIG. 5 (a) is the characteristics of this embodiment, and FIG. 5 (b) is the conventional one. This is the characteristic of the TFT liquid crystal display device.

First, referring to FIGS. 3 and 4, this TF
A manufacturing process of the T liquid crystal display device will be described. First, the transparent electrodes 2a and 2b for driving the liquid crystal of the sub-pixels 12a and 12b are formed on the transparent glass substrate 1a. Next, a silicon oxide film 3 is deposited as an insulating film. Then, the gate electrode 4 of the TFT is formed with a metal such as chromium. And TF
A silicon nitride film 5 serving as a gate insulating film of T15 is deposited thereon. Next, the semiconductor layer 6 forming the TFT 15 is formed. The resistance value of the semiconductor layer 6 changes according to the voltage applied to the gate electrode 4, and provides the function as a switch element. Next, contact holes 7a and 7b are opened in the insulating film layers of the silicon oxide film 3 and the silicon nitride film 5 on the transparent electrode 2a to expose a part of the transparent electrode 2a. Next, the source electrode 8a, the drain electrode 8b, the additional capacitance, and the control capacitance electrode 8d are simultaneously formed using a metal such as aluminum. At this time, the drain electrode 8b on the transparent electrode 2a is formed so that the drain electrode 8b and the transparent electrode 2a are connected through the contact hole 7a opened on the transparent electrode 2a. In addition, the transparent electrode 2a
The additional capacitance and control capacitance electrode 8d above is the transparent electrode 2a.
It is formed so that the additional capacitance and control capacitance electrode 8d and the transparent electrode 2a are connected through the contact hole 7b opened above. A control capacitor 13 is formed between the additional capacitor / control electrode 8d and the transparent electrode 2b, and the control capacitor 13 is connected in series with the sub-pixel 12b. Further, an additional capacitance 14 is formed between the additional capacitance / control capacitance electrode 8d and the gate electrode 4'of the preceding stage, and the additional capacitance 14 is arranged in parallel with the sub-pixel 12a and the sub-pixel 12b. . Through the above steps, the TFT array substrate is completed. After that, this substrate is bonded to another substrate 1b having a black stripe 9 formed in one part and a transparent electrode 10 deposited on one surface with a gap of about 5 μm formed, and a liquid crystal 10 is injected therebetween. And 2
Polarizing plates are arranged outside each of the substrates so that the angle formed by the polarization axes of the two polarizing plates is 90 degrees.

In this embodiment, as shown in the equivalent circuit of FIG. 4, the signal voltage (Vs) from the source electrode supplied from the TFT 15 is directly supplied to the liquid crystal layer in the sub-pixel 12a. On the other hand, the sub-pixel 12b has a configuration in which the additional capacitance and the control capacitance 13 (Cc) formed between the control capacitance electrode 8d and the transparent electrode 2b are connected in series with the pixel capacitance 12b (Clc2). The signal voltage (Vs) supplied from the control capacitor 13 and the pixel capacitor 12
The voltage is applied to the pixel 12b at a lower voltage than that of the pixel 12a. When this is expressed by an equation, Vlc1 = Vs Vlc2 = Vs × (Cc / (Clc2 + Cc)), and as a result, Vlc2 <Vlc1. Therefore, the light amount-signal voltage characteristic of the sub-pixel 2 to which the low voltage Vlc2 is applied shifts to the high signal voltage side.

Here, Cc is Cc: Clc2 (V5
The ratio of 0) was set to be 9: 5. The liquid crystal capacitance Clc2 changes its capacitance value depending on the applied voltage value, that is, the direction of arrangement of liquid crystal molecules. Where Clc2 (V
50) is the capacitance value when the amount of light from the sub-pixel 12b is 50% of the maximum amount of light when no voltage is applied (the liquid crystal molecules are arranged substantially parallel to the substrate). As a result,
In the light quantity-signal voltage characteristics observed from the front direction shown by, the light quantity-signal voltage gradient γ of the sub-pixel 1 and the sub-pixel 1
And the drive voltage difference ΔV of the sub-pixel 2 is set as follows.

[Gamma] = V10-V90 = 1.3V [Delta] V = V50'-V50 = 1.0V [gamma]-[Delta] V = 0.3V where V10, V50, and V90 are the light amount in front of the sub-pixel 1-the signal voltage. In the characteristics, the signal voltages which are 10%, 50%, and 90% with respect to the maximum light quantity when no voltage is applied, similarly V50 ′, are the light quantity-signal voltage characteristics of the front surface of the sub-pixel 2 when no voltage is applied. 5 for maximum light intensity
The signal voltage is 0%.

Further, the ratio of the display areas 20a and 20b of the sub-pixel 1 and the sub-pixel 2 shown in FIG. 3A is set to 7: 3. As a result, as shown in the light amount-signal voltage characteristic of the lower viewing angle θ = 40 ° in FIG. 2, the light amount-signal voltage characteristic of one pixel including the sub-pixel 1 and the sub-pixel 2 has a monotonically decreasing smooth characteristic. can get. Further, as shown in FIG. 5, in the characteristics of the conventional TFT liquid crystal display device of FIG.
It can be seen that the gradation inversion phenomenon observed in the range of 60 ° is eliminated at all angles by performing the present example, as shown in FIG.

It should be noted that this γ-ΔV is -0.2V <γ-Δ
V <0.8V, and even when the display area ratio of the sub-pixel 1 and the sub-pixel 2 is in the range of 8: 2 to 6: 4, the light amount-signal voltage characteristic of one pixel is similarly monotonically reduced and smooth. Various characteristics can be obtained.

With the above configuration, the conventionally observed gradation inversion phenomenon is eliminated. Further, the light amount-signal voltage curve for one pixel has a gentler slope than the conventional one. As described above, when gradation display is performed, the light amount difference between the gradation levels at the viewing angle in the main viewing angle direction becomes more uniform than in the conventional case. This alleviates the blackout phenomenon conventionally observed. By performing the present embodiment as described above, the display performance at the viewing angle in the main viewing angle direction is considerably improved as compared with the conventional one.

Next, a second embodiment will be described with reference to FIGS. FIG. 6 shows T observed from the front of the second embodiment.
It is a light amount-signal voltage characteristic of each pixel of the FT liquid crystal display device. FIG. 7 shows the light amount-signal voltage characteristics observed from θ = 40 °. FIG. 8 is a plan view of a TFT liquid crystal display device,
FIG. 9 is an equivalent circuit diagram of one pixel of the TFT liquid crystal display device. FIG. 10 shows a signal waveform diagram for driving the present TFT liquid crystal display device.

First, referring to FIGS. 8 and 9, this TF
The configuration of the T liquid crystal display device will be described. The manufacturing process is the same as in the first embodiment. In the second embodiment, two TFTs 15a and 15b are formed in one pixel.
Then, sub-pixels 12a and 12b connected to the respective TFTs 15a and 15b are formed. Further, the additional capacitances 14a and 14b are provided to the sub-pixels 12a and 12b, respectively.
Are formed. The additional capacitors 14a and 14b are formed between the additional capacitor electrodes 8c and 8c 'and the preceding gate electrode 4'.

Next, a driving method of the present TFT liquid crystal display device will be described with reference to FIG. Here, V (Gn) is a signal supplied to the gate electrode 4, V (Gn-1) is a signal supplied to the preceding gate electrode 4 ', and V (S) is supplied to the source electrode 8a. Signal V (lc) indicates a signal waveform applied to each sub-pixel. The TFTs 15a and 15b function as switching elements, and the pulse signal V (Gn) supplied during the period T2 of the gate electrode 4 turns on the TFTs 15a and 15b on the gate electrode. Then, the signal V (S) supplied to the source electrode 8a is similarly supplied to the pixels 12a and 12b via the TFTs 15a and 15b in the ON state. Next, at the end of the period T3, V (lc) is generated by the modulation signal of the signal V (Gn-1) supplied to the gate electrode 4'of the previous stage.
Changes. The amount of change is determined by the additional capacitances Cst1 and Cst2 of the sub-pixels, the liquid crystal capacitances Clc1 and Clc2,
It depends on the sizes of the gate-drain capacitances Cgd1 and Cgd2. By changing any of these values in the sub-pixels 1 and 2, the voltage value applied to the liquid crystal of each sub-pixel can be changed to Vlc1 and Vlc2. The voltages Vlc1 and Vlc2 applied to each subpixel are
It can be expressed by the following formula.

Vlc1 = Vs + (Cst1 / Ctotal1) × Vge Ctotal1 = Cst1 + Clc1 + Cgd1 Vlc2 = Vs + (Cst2 / Ctotal2) × Vge Ctotal2 = Cst2 + Clc2 + Cgd2 Here, Vge1 / Cto (Cto = 12V).
1) = 0.53, (Cst2 / Ctotal2) = 0.
It was set to 29. As a result, the light amount-signal voltage gradient γ of the sub-pixel 1 and the driving voltage difference ΔV between the sub-pixel 1 and the sub-pixel 2 observed from the front shown in FIG. 6 were set as follows.

Γ = V10-V90 = 1.7V ΔV = V50'-V50 = 1.5V γ-ΔV = 0.2V Further, the display areas 20a and 20b of the sub-pixel 1 and the sub-pixel 2 shown in FIG. The ratio was 8: 2.

Note that this γ-ΔV is -0.4V <γ-Δ
V <0.6V, and even when the ratio of the display areas 20a and 20b is in the range of 9: 1 to 7: 3, the light amount-signal voltage characteristic of one pixel is similarly monotonically reduced and a smooth characteristic is obtained. .

With the above structure, the gradation inversion phenomenon observed conventionally is eliminated. Also, the light amount of one pixel −
The signal voltage curve has a gentler slope than the conventional one. As described above, in the case of gradation display, the difference in the light amount between the levels becomes more uniform than the difference in the light amount between the levels in the conventional configuration. This alleviates the blackout phenomenon conventionally observed. By performing the present embodiment as described above,
At the viewing angle in the main viewing angle direction, the display performance is significantly improved compared to the conventional one.

[0027]

As described above, according to the present invention, two or more sub-pixels forming a pixel are set to have appropriate driving voltage differences and display area ratios, so that the light is observed at the viewing angle in the main viewing angle direction. The intensity-signal voltage characteristic is improved, the display performance can be improved considerably as compared with the conventional case, and the gradation inversion phenomenon observed in the past disappears. Also, the light amount-signal voltage curve for one pixel is
The inclination is gentler than in the conventional case, and when gradation display is performed, the difference in the light amount between the levels becomes more uniform than the difference in the light amount between the levels in the conventional configuration. This alleviates the blackout phenomenon conventionally observed. Further, the liquid crystal display device of the present invention can be manufactured by almost the same method as the conventional one, and the cost is hardly increased in order to realize the present liquid crystal display device.

[Brief description of drawings]

FIG. 1 shows T observed from the front in the first embodiment of the present invention.
Light quantity-signal voltage characteristic diagram from each pixel of FT liquid crystal display device

FIG. 2 is a light amount-signal voltage characteristic diagram of each pixel of the TFT liquid crystal display device observed from a lower viewing angle θ = 40 ° in the first embodiment of the present invention.

FIG. 3A is a plan view of a TFT liquid crystal display device according to the first embodiment of the present invention, and FIG.
Cross-sectional configuration view taken along the line aa 'and seen from the lateral direction

FIG. 4 is an equivalent circuit diagram of one pixel of the TFT liquid crystal display device according to the first embodiment of the present invention.

FIG. 5: Light intensity observed in the range of downward viewing angle θ = 0 to 60 °
In the signal voltage characteristics (the scale of the vertical axis is enlarged and the gradation inversion unit is enlarged), (a) is the first embodiment of the present invention,
(B) is a characteristic diagram of a conventional TFT liquid crystal display device

FIG. 6 shows T observed from the front in the second embodiment of the present invention.
Light amount-signal voltage characteristic diagram of each pixel of FT liquid crystal display device

FIG. 7 is a light amount-signal voltage characteristic diagram of each pixel of the TFT liquid crystal display device observed from a lower viewing angle θ = 40 ° in the second embodiment of the present invention.

FIG. 8 is a plan configuration diagram of a TFT liquid crystal display device according to a second embodiment of the present invention.

FIG. 9 is an equivalent circuit diagram of one pixel of the TFT liquid crystal display device according to the second embodiment of the present invention.

FIG. 10 is a signal waveform diagram for driving a TFT liquid crystal display device according to a second embodiment of the present invention.

11A is a plan view of a TFT liquid crystal display device in the conventional example, and FIG. 11B is a cross-sectional view taken along the line aa ′ and bb ′ in FIG. Diagram

FIG. 12 is an equivalent circuit diagram of one pixel of the TFT liquid crystal display device according to the second embodiment of the present invention.

FIG. 13 is a signal waveform diagram for driving a TFT liquid crystal display device in a conventional example.

FIG. 14 is a schematic diagram of luminance-driving voltage characteristics of a liquid crystal display device when observed at angles of θ = 0 ° and θ> 0 ° in a conventional example.

FIG. 15 is a schematic diagram showing a viewpoint when measuring a viewing angle characteristic of a liquid crystal display device.

[Explanation of symbols]

 1a, 1b Glass substrate 2a, 2b Transparent electrode 3 Silicon oxide film 4, 4'Gate electrode 5 Silicon nitride film 6 Semiconductor film 7a, 7b Contact hole 8a Source electrode 8b, 8b 'Drain electrode 8c, 8c' Additional capacitance electrode 8d Additional Capacitance and control capacitance electrode 9 Black matrix 10 Transparent electrode 11 Liquid crystal 12a, 12b Pixel (or pixel capacitance) 13 Control capacitance 14, 14a, 14b Additional capacitance 15, 15a, 15b Thin film transistor (TFT) 20a Sub-pixel 1 display portion 20b Display parts 21a, 21b of sub-pixel 2 Direction of alignment treatment of liquid crystal molecules

Claims (4)

[Claims] 1. A liquid crystal is sandwiched between two substrates, pixels are arranged in a matrix on a plane of the substrate, the pixels are formed by a plurality of sub-pixels, and each of the plurality of sub-pixels constitutes the plurality of sub-pixels. The liquid crystal layer has means for applying voltages of different magnitudes, and the inclination angle from the vertical line of the substrate along the long axis direction of the liquid crystal molecules positioned in the middle of the liquid crystal layer when no voltage is applied is 0 ° to The display area ratio of the plurality of sub-pixels of the pixel and the driving voltage difference of the light amount-signal voltage characteristic of each sub-pixel are set so that the light amount-signal voltage characteristic observed from the position of 40 ° monotonously decreases or monotonically increases. A liquid crystal display device characterized by being set. 2. The liquid crystal display device according to claim 1, wherein the pixel is composed of two sub-pixels. 3. The drive voltage difference ΔV of the light amount-signal voltage characteristics observed from the front of the device of the two sub-pixels is −0.5 V <γ-ΔV <1.0 γ = | V10-V90 | ΔV = V50 '. -V50 (Here, V10, V50, and V90 are 10%, 50%, and 9% with respect to the maximum light amount in the light amount-signal voltage characteristics of the subpixel to which a high voltage is applied to the liquid crystal layer.
The signal voltage is 0%, and similarly, V50 'is a signal voltage that is 50% with respect to the maximum light amount in the light amount-signal voltage characteristics of the sub-pixel to which the low voltage is applied to the liquid crystal layer.) 3. The liquid crystal display device according to claim 2, wherein the liquid crystal display device is set in the range. 4. The liquid crystal display device according to claim 3, wherein the display area ratio of the two sub-pixels is in the range of 9: 1 to 6: 4.