JPH10123478A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device with high luminous intensity, high contrast and low power consumption by specifying an angle, etc., between an axial direction of an optical film and the major axial direction of a liquid crystal molecule of a liquid crystal display panel close to it. SOLUTION: The angle A between the axial direction of the optical film of an outgoing side and the major axial direction of the liquid crystal molecule close to it, the angle B between the optical axial direction of the optical film of an incident side and the major axial direction of the liquid crystal molecule close to it, and the angle C between a polarization axial direction of a polarizing plate of the outgoing side and the optical axial direction of the optical film are set respectively. That is, the angle A between the optical axial direction of the optical film of the outgoing side of light and the major axial direction of the liquid crystal molecule of the liquid crystal display panel close to it is set in between 50-90 deg.. Further, the angle A between the optical axial direction of the outgoing side of the light and the major axial direction of the liquid crystal molecule close to it is made smaller than the angle B between the optical axial direction of the incident side of the light and the major axial direction of the liquid crystal molecule close to it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device, and more particularly to a super twisted nematic liquid crystal display device.

[0002]

2. Description of the Related Art A liquid crystal display device currently used is a twisted nematic (hereinafter referred to as TN) having a structure in which the arrangement direction of nematic liquid crystal molecules is twisted by 90 degrees on the surface of a pair of upper and lower electrode substrates. Abbreviated) mode, in which the arrangement direction of nematic molecules between the upper and lower electrode substrates is 1
There are a type using a super-twisted nematic (hereinafter abbreviated as STN) mode using a birefringence effect by twisting at 80 to 300 degrees, and a type using a ferroelectric liquid crystal.

FIG. 8 shows a conventional STN mode liquid crystal display device. That is, the pair of glass substrates 11
A transparent electrode 12 is provided on each of them, a liquid crystal alignment film 13 is applied on the surface thereof, a spacer / seal resin 14 is provided on one of such glass substrates, and the glass substrate is bonded and cured with the other glass substrate. After that, a liquid crystal 15 is injected between the two to form a panel, and elliptically polarizing plates 16 are provided on both sides of the panel.
Is affixed.

The liquid crystal display device having the structure shown in FIG. 8 can perform display by utilizing the difference in light transmittance at the time of on / off by multiplex driving.
It is widely used in OA fields such as word processors and personal computers utilizing the steep threshold characteristics of the mode. In addition, with the recent progress in colorization of liquid crystal displays, liquid crystal display devices having a color filter in a liquid crystal panel are rapidly spreading, and vividness and brightness of colors have become important factors.

[0005] In order to realize color vividness, it is first necessary to realize good black and white display. Means for realizing a good monochrome display in the STN mode are a so-called two-layer method of compensating the elliptically polarized state of light passing through the liquid crystal panel with another liquid crystal panel, and a liquid crystal for optical compensation. It is known that there is a method called a so-called FSTN in which a panel is replaced with an optical film (for example, see Japanese Patent Application Laid-Open No. 64-519). At present, in the field of word processors and personal computers, the latter is generally used from the viewpoint of weight and cost.

However, according to the conventional method, not only the Δn · d of the liquid crystal panel and the configuration of the elliptically polarizing plate but also the liquid crystal material causes a considerable difference in the transmitted light spectrum at the time of off, so that a good monochrome display can be realized. For this purpose, there is a problem that the liquid crystal material must be optimized.

FIG. 9 shows the difference in the transmitted light spectrum of the liquid crystal panel in the off state depending on the liquid crystal material. The two types of liquid crystal materials A and B will be described.
The twist angles are 0.84 and 250 degrees for all liquid crystal materials. In the liquid crystal material A, a flat transmitted light spectrum is realized over almost the entire wavelength region of visible light, and a good black-and-white display can be realized. In the liquid crystal material B, the transmittance of light on the short wavelength side is high, and the liquid crystal material B is blue. It can be seen that the display is colored black.

In particular, in the case of a color liquid crystal display device using a color filter, there is a problem that the ON state becomes dark because the panel transmittance is reduced as described later.

[0009]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned problems, and eliminates coloring in an off state and improves brightness in an on state regardless of a liquid crystal material. By doing so, high brightness, high contrast,
It is an object to provide a liquid crystal display device with low power consumption. Still another object of the present invention is to provide a liquid crystal display device suitable for color display.

[0010]

In order to achieve the above object, a liquid crystal display device according to the present invention has the following features.

That is, in a liquid crystal display device in which an elliptically polarizing plate composed of a polarizing plate and an optical film is stuck on both sides of a liquid crystal display panel, the optical axis direction of the optical film and the liquid crystal molecules of the liquid crystal display panel adjacent to the optical film. The angle between the major axis direction is between 50 and 90 degrees, and the angle between the optical axis direction of one of the light emission side and the incidence side and the major axis direction of the liquid crystal molecules adjacent thereto is: A liquid crystal display device characterized in that the angle is smaller than the angle between the other optical axis direction and the long axis direction of the liquid crystal molecules adjacent thereto.

That is, according to the present invention, the angle between the optical axis direction of the optical film and the major axis direction of the liquid crystal molecules of the liquid crystal display panel adjacent thereto is between 50 and 90 degrees.
Contrast and brightness can be improved.

According to the present invention, in addition to the above-described structure, the angle between the optical axis direction of one of the light emission side and the light incidence side and the major axis direction of the liquid crystal molecules adjacent thereto is set to the other. By making the angle smaller than the angle between the optical axis direction and the long axis direction of the liquid crystal molecules adjacent thereto, the brightness is further improved as compared with the case where only the above-described configuration is used, and in almost the entire wavelength region of the visible light region. A flat transmitted light spectrum can be obtained, and an off state without coloring can be obtained. As a result, regardless of the liquid crystal material, coloring in an off state can be eliminated and brightness in an on state can be improved.

Therefore, according to the present invention, irrespective of the liquid crystal material, by eliminating the coloring in the off state and improving the brightness in the on state, high brightness and high contrast can be achieved, and the backlight is improved. Since there is no need to take measures such as increasing the luminance of the liquid crystal display, a liquid crystal display device with low power consumption can be provided.

In another liquid crystal display device according to the present invention, an elliptically polarizing plate comprising a polarizing plate and an optical film is attached to both sides of a liquid crystal display panel, and is provided on at least one substrate constituting the liquid crystal display panel. In a color liquid crystal display device having a color filter, the color filter layer is on the light emission side.
Therefore, a liquid crystal display device suitable for color display can be provided. Details of the reason will be described later.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is a liquid crystal display device comprising an elliptically polarizing plate comprising a polarizing plate and an optical film attached to both sides of a liquid crystal display panel.
The angle between the optical axis direction of the optical film and the major axis direction of the liquid crystal molecules of the liquid crystal display panel adjacent to the optical film is between 50 and 90 degrees, and one of the light emitting side and the light incident side is formed. An angle formed between the axial direction and the long axis direction of the liquid crystal molecules adjacent thereto is smaller than the angle formed between the other optical axis direction and the long axis direction of the liquid crystal molecules adjacent thereto. With such a structure, as described above, regardless of the liquid crystal material, a low power consumption liquid crystal display device can be provided which eliminates coloring in an off state and improves brightness in an on state. It has the action of:

According to a second aspect of the present invention, in the liquid crystal display device according to the first aspect, an angle between an optical axis direction on a light emitting side and a long axis direction of liquid crystal molecules adjacent thereto is formed on a light incident side. Is smaller than the angle between the direction of the optical axis and the major axis direction of the liquid crystal molecules adjacent thereto. Even with such a structure, regardless of the liquid crystal material, there is an effect that a low-power-consumption liquid crystal display device that eliminates coloring in an off state and improves brightness in an on state can be provided.

According to a third aspect of the present invention, in the liquid crystal display device according to the second aspect, an angle between an optical axis direction on a light emitting side and a long axis direction of liquid crystal molecules adjacent thereto is formed on a light incident side. Is smaller by 1 to 10 degrees than the angle between the optical axis direction and the major axis direction of the liquid crystal molecules adjacent thereto. Even with such a structure, regardless of the liquid crystal material, there is an effect that a low-power-consumption liquid crystal display device that eliminates coloring in an off state and improves brightness in an on state can be provided.

The invention according to claim 4 is the invention according to claims 1 to 3
The liquid crystal display device according to any one of the above, wherein the angle between the polarization axis direction of the polarizing plate and the optical axis direction of the optical film on the light emission side is 30 degrees or less. . Even with such a structure, regardless of the liquid crystal material, there is an effect that a low-power-consumption liquid crystal display device that eliminates coloring in an off state and improves brightness in an on state can be provided.

The invention described in claim 5 is the invention according to claims 1 to 4
The liquid crystal display device according to any one of the above, wherein the steepness (V50 / V10) of the liquid crystal is less than 1.035. Even in such a case, regardless of the liquid crystal material, the coloring in the off state is eliminated,
In addition, there is an effect that a low-power-consumption liquid crystal display device which improves brightness in an on state can be provided.

[0021] The invention according to claim 6 is the invention according to claims 1 to 5.
The liquid crystal display device according to any one of the above, wherein Δn · d of the liquid crystal panel is less than 0.89. Even with such a structure, regardless of the liquid crystal material, there is an effect that a low-power-consumption liquid crystal display device that eliminates coloring in an off state and improves brightness in an on state can be provided.

According to a seventh aspect of the present invention, an elliptically polarizing plate comprising a polarizing plate and an optical film is attached to both sides of a liquid crystal display panel, and a color filter is formed on at least one substrate constituting the liquid crystal panel. Wherein the color filter layer is on the light emission side. Such a structure has an effect that a liquid crystal display device suitable for color display can be provided.

According to an eighth aspect of the present invention, in the liquid crystal display device according to the seventh aspect, the angle between the optical axis direction of the optical film and the major axis direction of the liquid crystal molecules of the liquid crystal display panel adjacent thereto is 50 to 90. And the angle between the optical axis direction of one of the light exit side and the incident side and the major axis direction of the liquid crystal molecule adjacent thereto is different from that of the other optical axis direction. Is smaller than the angle formed by the long axis direction. If something like this,
Regardless of the liquid crystal material, it is possible to provide a low power consumption liquid crystal display device which eliminates coloring in an off state and improves brightness in an on state, and further provides a liquid crystal display device suitable for color display. It has the effect of being able to.

According to a ninth aspect of the present invention, in the liquid crystal display device according to the eighth aspect, an angle between an optical axis direction on a light emitting side and a long axis direction of liquid crystal molecules adjacent thereto is formed on a light incident side. Is smaller than the angle between the optical axis direction and the major axis direction of the liquid crystal molecules adjacent thereto. Even with such a structure, regardless of the liquid crystal material, a low power consumption liquid crystal display device that eliminates coloring in an off state and improves brightness in an on state can be provided. The liquid crystal display device can be provided.

According to a tenth aspect of the present invention, in the liquid crystal display device according to the ninth aspect, the angle between the optical axis direction on the light emitting side and the major axis direction of the liquid crystal molecules adjacent thereto is equal to the light incident side. Is smaller by 1 to 10 degrees than the angle between the optical axis direction and the major axis direction of the liquid crystal molecules adjacent thereto. Even with such a structure, regardless of the liquid crystal material, a low power consumption liquid crystal display device that eliminates coloring in an off state and improves brightness in an on state can be provided. The liquid crystal display device can be provided.

[0026] According to an eleventh aspect of the present invention, in the liquid crystal display device according to any one of the seventh to tenth aspects,
The angle between the direction of the polarization axis of the polarizing plate on the light emission side and the direction of the optical axis of the optical film is 30 degrees or less. Even with such a structure, regardless of the liquid crystal material, a low power consumption liquid crystal display device that eliminates coloring in an off state and improves brightness in an on state can be provided. The liquid crystal display device can be provided.

According to a twelfth aspect of the present invention, in the liquid crystal display device according to any one of the seventh to eleventh aspects, the steepness (V50 / V10) of the liquid crystal is 1.035.
It is characterized by being less than. Even with such a configuration, a low power consumption liquid crystal display device that eliminates coloring in an off state and improves brightness in an on state can be provided regardless of a liquid crystal material, and is suitable for color display. The liquid crystal display device can be provided.

According to a thirteenth aspect of the present invention, in the liquid crystal display device according to any one of the seventh to twelfth aspects,
The liquid crystal panel is characterized in that Δn · d is less than 0.89. Even with such a structure, regardless of the liquid crystal material, a low-power-consumption liquid crystal display device capable of eliminating coloring in an off state and improving brightness in an on state can be provided. The liquid crystal display device suitable for display can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 shows a sectional structure of a liquid crystal display device of the present invention. That is, on the glass substrate 11, a transparent electrode 12, specifically, a transparent electrode of ITO (indium tin oxide) or tin oxide is provided. On the surface of the transparent electrode 12, an undercoat film such as an insulating film, a color filter, and a color filter overcoat may be formed for the purpose of preventing elution of alkali from the glass substrate 11. Insulating film on top of
An overcoat film such as a color filter film may be formed. The configuration of these electrodes, undercoat, and other components in the cell can be the same as the configuration of a conventionally known liquid crystal display device.

A liquid crystal alignment film 13 of polyimide is applied by printing on a glass substrate 11 on which a transparent electrode 12 is provided, and a heat treatment is performed. Thereafter, the liquid crystal alignment film surface is twisted rightward with a cloth of a polymer such as nylon. Rubbing process is performed.

A pair of such glass substrates 11 is prepared,
A spacer / seal resin 14 is placed on one of the glass substrates, and is bonded to the other glass substrate and cured. After that, a liquid crystal 15 twisted and oriented 180 degrees or more is injected between the two substrates 11, 11, and an elliptically polarizing plate 16 composed of a polarizing plate and an optical film is attached to both sides of the panel to complete the liquid crystal display device. I got it.

Table 1 shows that the angle between the optical axis direction of the optical film of the liquid crystal display device thus obtained and the major axis direction of the liquid crystal molecules of the liquid crystal display panel adjacent thereto is based on the present invention. Data showing a specific example showing a difference in optical characteristics between a case where the angle is set to 90 degrees (Case 1) and another case (Case 2), that is, a case outside the scope of the present invention. is there.

[0033]

[Table 1]

Case 1 is a case where the angle between the optical axis direction of the optical film in the elliptically polarizing plate 16 and the major axis direction of the liquid crystal molecules of the liquid crystal display panel adjacent thereto is 83 degrees.
Case 2 has an angle between the optical axis direction of the optical film and the major axis direction of the liquid crystal molecules of the liquid crystal display panel adjacent to the optical film direction, which is 40 degrees.
This is the case for degrees. The measurement conditions are both 1/300 Dut
y, performed at 1/18 Bias. In both cases 1 and 2, the panel Δn · d = 0.84, the twist angle ω = 250 degrees, and the sharpness γ of the liquid crystal (V50 / V10)
= 1.030.

As is clear from Table 1, in case 1 based on the present invention, good display characteristics were obtained in both contrast and brightness, but in case 2 out of the present invention, both contrast and brightness were low. Good display characteristics were not obtained.

Table 2 shows data of another specific example which was examined in the same manner as in Table 1.

[0037]

[Table 2]

Case 1 based on the present invention is a case where the angle between the optical axis direction of the optical film and the major axis direction of the liquid crystal molecules of the liquid crystal display panel adjacent thereto is 65 degrees. Case 2 not covered by the present invention is a case where the angle between the optical axis direction of the optical film and the major axis direction of the liquid crystal molecules of the liquid crystal display panel adjacent thereto is 45 degrees. Measurement conditions are 1/3 for both
The test was performed at 00 Duty, 1/18 Bias. In case 1 and case 2, Δn · d = 0.8
9. Twist angle ω = 240 degrees, steepness γ of liquid crystal (V50
/ V10) = 1.025.

In these results, in case 1 based on the present invention, good display characteristics were obtained in both contrast and brightness, but in case 2 out of the present invention, both contrast and brightness were low, and good display was obtained. No properties were obtained. Therefore, in order to reduce the contrast and brightness to a level that does not pose a problem in practical use, the angle between the optical axis direction of the optical film and the major axis direction of the liquid crystal molecules of the liquid crystal display panel adjacent thereto is 50 to 90 degrees. Must be set in between.

However, even if the angle between the optical axis direction of the optical film and the major axis direction of the liquid crystal molecules of the liquid crystal display panel adjacent thereto is set between 50 and 90 degrees, the contrast is maintained as described above. For this purpose, it is necessary to make the angles formed by the optical axis directions of the optical films on the light emitting side and the incident side and the major axis direction of the liquid crystal molecules close thereto close. However, in such a liquid crystal display device, it is necessary to take measures such as increasing the luminance of a backlight in order to improve display characteristics (particularly brightness), and it is difficult to reduce power consumption.

The problem is that the angle between the optical axis direction of one of the light emitting side and the incident side and the major axis direction of the liquid crystal molecule adjacent thereto is different from that of the other optical axis direction. Is solved by making the angle smaller than the angle with the major axis direction. Preferably, the angle between the optical axis direction on the light emission side and the major axis direction of the liquid crystal molecules adjacent thereto is smaller than the angle between the optical axis direction on the light incident side and the major axis direction of the liquid crystal molecules adjacent thereto. Is also solved by making it smaller.

Table 3 is a table showing the optical characteristics of the liquid crystal display device having the elliptically polarizing plate structure of the present invention and the liquid crystal display device having the conventional structure. In the table, A to C represent the angle (A) between the optical axis direction of the optical film on the emission side and the long axis direction of the liquid crystal molecules adjacent thereto, and the optical axis direction of the optical film on the incident side and the liquid crystal adjacent thereto. An angle (B) between the long axis direction of the molecule and an angle (C) between the polarization axis direction of the exit-side polarizing plate and the optical axis direction of the optical film is shown in detail in FIG. According to Table 3, the angle A between the direction of the optical axis on the light emitting side and the major axis direction of the liquid crystal molecules adjacent thereto is shown.
Is smaller than the angle B between the optical axis direction of the light incident side and the major axis direction of the liquid crystal molecules adjacent thereto, the liquid crystal display device of the present invention provides a light emitting side and a light incident side of each optical film. It can be seen that it is about 10% brighter than a conventional liquid crystal display device having the same angle between the optical axis direction and the long axis direction of the liquid crystal molecules adjacent thereto.

[0043]

[Table 3]

FIG. 3 is a characteristic diagram showing a panel transmitted light spectrum of the liquid crystal display device in an off state. FIG.
Therefore, the liquid crystal display device having the conventional configuration is not suitable for a liquid crystal material having a Δ
The light of the short wavelength side is transmitted depending on the wavelength dispersion characteristic of n, and an off state colored blue is obtained. On the other hand, the liquid crystal display device of the present invention is flat in almost the entire wavelength region of the visible light region. It was found that a transmitted light spectrum was obtained and an off state without coloring was obtained.

When this result is evaluated based on the measurement results of the (x, y) chromaticity coordinates in Table 3, the liquid crystal display device having the conventional configuration clearly has a blue tint in the off state while being colored blue. The off-state tint of the liquid crystal display device of the present invention shows almost the same coordinates as the (x, y) chromaticity coordinates of the on-state, indicating that an ideal off-state without coloring is obtained.

In Table 3, the numerical contrast of the liquid crystal display device of the present invention is lower than that of the liquid crystal display device having the conventional structure. By improving the black color purity of the liquid crystal display device, a higher impression can be given in terms of a sensual contrast than in a liquid crystal display device having a conventional configuration.

FIG. 4 is a schematic diagram schematically showing the reason why the above-described effects can be obtained by the configuration of the present invention.
FIG. 4A shows the off-state elliptically polarized light state of the liquid crystal display device having the structure of the present invention, and FIG. 4B shows the off-state elliptically polarized light state of the liquid crystal display device having the conventional structure. is there. The reason that the off state is colored blue in the conventional configuration is that, in elliptically polarized light of each wavelength of red R, green G, and blue B that has passed through the panel, the red R and green G are relatively condensed by the optical film on the emission side. On the other hand, elliptically polarized light in the blue B wavelength region is generally perpendicular to the polarization axis on the emission side, whereas color dispersion cannot generally be compensated for by the optical film alone because the wavelength dispersion of Δn of the liquid crystal increases on the short wavelength side. This is because it has a property of easily passing through the polarizing plate. Therefore, in the liquid crystal display device having the conventional configuration, although the absolute transmittance in the off state is low, the off state is colored blue. On the other hand, the present invention shifts the optical axis direction of the optical film on the output side by a predetermined angle in a predetermined direction so that elliptically polarized light on the long wavelength side is transmitted, and the optical axis direction of the optical film on the incident side and the optical film on the output side. And the angle formed by the long axis direction of the liquid crystal molecules adjacent to each other is asymmetrical, and the absolute transmittance in the off state increases, but at the same time, a good off state without coloring is realized by canceling the bluish color. , The brightness in the ON state can be improved.

According to the above viewpoint, the angle between the direction of the optical axis on the light exit side and the major axis direction of the liquid crystal molecules adjacent thereto is defined as follows. Specifically, it can be said that it is preferable that the angle is smaller by 1 to 10 degrees than the angle formed by the long axis direction.

Further, it can be said that the angle between the direction of the polarization axis of the polarizing plate on the light emission side and the direction of the optical axis of the optical film is preferably 30 degrees or less. FIG. 5 shows BV characteristics of the liquid crystal display device having the configuration of the present invention and the liquid crystal display device having the conventional configuration. The solid line indicates the liquid crystal display device having the configuration of the present invention, and the broken line indicates the liquid crystal display device having the conventional configuration. It can be seen that the brightness on the high voltage side where the liquid crystal molecules have risen considerably differs, and at the same time the bottom shape of the BV characteristic differs in the voltage region with the lowest transmittance. That is, it can be seen that the bottom shape of the liquid crystal display device having the configuration of the present invention is flat with respect to the voltage, whereas the bottom shape of the liquid crystal display device having the conventional configuration has an acute angle. For this reason, it is considered that the liquid crystal display device having the structure of the present invention is advantageous against a change in the off state with respect to the voltage. Further, not only the threshold unevenness in the display area is reduced, but also the threshold unevenness due to the temperature fluctuation and the luminance gradient due to the voltage attenuation are reduced.

Table 4 shows the results of a similar study of two types of liquid crystals having different steepnesses, and shows the respective structures. In addition, A to C in the table are angles formed by the various axial directions described above. According to this result, the sharpness γ (V50
/ V10) is 1.035 or more, it has been found that the effect of the present invention is reduced. Therefore, the sharpness γ of the liquid crystal
It can be said that (V50 / V10) is preferably less than 1.035.

[0051]

[Table 4]

Table 5 shows that the panels have different Δn · d values.
FIG. 9 shows the results of similar examinations of various types of panels and respective configurations. In addition, A to C in the table are angles formed by the various axial directions described above. From this result, it was found that the effect of the present invention was reduced when Δn · d of the liquid crystal was 0.89 or more. Therefore, it can be said that Δn · d of the liquid crystal display panel is preferably less than 0.89.

[0053]

[Table 5]

Next, an embodiment of a liquid crystal display device having a color filter layer on at least one substrate, in which the color filter layer is placed on the light emission side, will be described with reference to the drawings. Will be explained. (Embodiment 2) FIG. 7 shows a conventional liquid crystal display device having a color filter layer on at least one substrate. FIG. 6 shows a liquid crystal display device of the present invention. A conventional liquid crystal display device having a color filter layer shown in FIG.
2 and a color filter layer 17 composed of a color filter and a color filter overcoat is formed on the surface of the transparent electrode 12.

In the case of the present invention shown in FIG.
2. Specifically, a liquid crystal alignment film 13 of a polyimide film is applied by printing on a transparent glass substrate 11 provided with a transparent electrode of ITO (indium tin oxide) or tin oxide, and is subjected to a superheat treatment. The surface of the liquid crystal alignment film is rubbed with a polymer cloth such as nylon so that the liquid crystal is twisted right.

On the surface of the transparent electrode 12, an undercoat film such as an insulating film may be formed for the purpose of preventing elution of alkali from the glass substrate 11. Further, an overcoat film such as an insulating film and a color filter film may be formed on the transparent electrode 12. The configuration of these electrodes, undercoat, and other components in the cell can be the same as the configuration of the conventional liquid crystal display device.

A spacer / seal resin 14 is placed on one of the pair of glass substrates 11 and the other glass substrate is laminated and cured.
The liquid crystal 15 twisted and oriented to 180 degrees or more is injected into both substrates, and an elliptically polarizing plate 16 composed of a polarizing plate and an optical film is injected.
On both sides of the panel to obtain a liquid crystal display device.

In the conventional color liquid crystal display device shown in FIG. 7, one pixel must be divided into three each for red, green and blue. Therefore, from the viewpoint of ITO patterning accuracy, on the scanning side substrate having a small number of lines, That is, it is customary to position the color filter layer 17 on the light incident side. However, in such a conventional color liquid crystal display device,
The display is very dark, and the current situation is that the brightness of the backlight is actually increased to cope with the situation. Therefore, in a liquid crystal display device that requires low power consumption such as a notebook personal computer, it is not possible to improve the brightness, the brightness, and the power consumption by comprehensively improving the liquid crystal material, the panel configuration, the elliptically polarizing plate configuration, and the like. It is a very important issue.

Table 6 shows that, in a color liquid crystal display device having a color filter on at least one substrate, a color filter layer is provided on the light incident side according to the present invention, and the color filter layer is provided on the light emitting side as in the prior art. It shows a difference in optical characteristics from the case where the device is installed. As is clear from Table 6, in the liquid crystal display device of the present invention in which the color filter layer is on the emission side, the brightness is improved by about 10% as compared with the conventional liquid crystal display device in which the color filter layer is on the incidence side. The results were obtained by turning the same panel upside down, and the 10% improvement in brightness obtained as an effect was due to the configuration of the elliptically polarizing plate and the panel optical constants (panel Δn · d, twist angle ω , The steepness γ of the liquid crystal, etc.), but clearly due to the fact that the color filter layer is located on the light emission side.

[0060]

[Table 6]

In the prior art, as described above, the color filter layer is usually on the light incident side. Also, prior art documents (for example, Japanese Patent Application Laid-Open No. 5-264955) show that the light-shielding layer (black matrix) on the emission side prevents light leakage from non-electrode portions and improves the contrast. But
The significance of the optical characteristics by setting the color filter layer on the output side and setting the color filter layer on the output side is not particularly shown. Therefore, by arranging the color filter layer on the light emission side as in the present invention, it is possible to obtain a unique effect that is completely different from the prior art, that is, the brightness in the ON state is improved and the power consumption is reduced. be able to. (Embodiment 3) Table 7 shows that, in addition to the configuration in which the color filter layer is on the emission side, the angle between the optical axis direction of the optical film and the major axis direction of the liquid crystal molecules of the liquid crystal display panel adjacent thereto is 50. The angle between the optical axis direction of one of the light exit side and the incident side and the major axis direction of the liquid crystal molecules adjacent thereto is close to the other optical axis direction. FIG. 6 shows a difference in optical characteristics between a liquid crystal display device of the present invention having an elliptically polarizing plate configuration smaller than an angle formed with a major axis direction of liquid crystal molecules and a liquid crystal display device having a conventional configuration.

As is clear from Table 7, it was found that the liquid crystal display device having the above-described structure of the present invention improved the brightness by about 20% as compared with the liquid crystal display device having the conventional structure. As a result, the backlight power can be reduced by about 20%.

[0063]

[Table 7]

[0064]

According to the present invention, there is provided a liquid crystal display device in which an elliptically polarizing plate comprising a polarizing plate and an optical film is attached to both sides of a liquid crystal display panel, respectively. The angle between the liquid crystal molecules of the display panel and the major axis direction is between 50 and 90 degrees, and
The angle between the optical axis direction of one of the light emitting side and the incident side and the major axis direction of the liquid crystal molecules adjacent thereto is smaller than the angle between the other optical axis direction and the major axis direction of the liquid crystal molecules adjacent thereto. By making it small, regardless of the liquid crystal material, it is possible to eliminate the coloring in the off state and improve the brightness in the on state, and to achieve high luminous intensity, high contrast, and low power consumption. An apparatus can be provided.

In a color liquid crystal display device having a color filter layer on at least one substrate, the color filter layer is positioned on the light emission side,
Further, in addition to this configuration, the angle between the optical axis direction of the optical film and the major axis direction of the liquid crystal molecules of the liquid crystal display panel close to the optical film is between 50 and 90 degrees, and the light exit side or the incident side. An elliptically polarizing plate in which the angle between one of the optical axis directions and the long axis direction of the liquid crystal molecules adjacent thereto is smaller than the angle between the other optical axis direction and the long axis direction of the liquid crystal molecules adjacent thereto. By applying the structure, regardless of the liquid crystal material, coloring in the off state can be eliminated and brightness in the on state can be improved, and high brightness, high contrast, and low consumption suitable for color display can be achieved. A power-consuming liquid crystal display device can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a schematic configuration of a liquid crystal display panel according to the present invention.

FIG. 2 is a schematic diagram showing angles formed by various axis directions of an elliptically polarizing plate and a major axis direction of liquid crystal molecules.

FIG. 3 is a characteristic diagram showing a panel transmitted light spectrum in an off state.

FIG. 4 is a schematic diagram showing an elliptically polarized light state of light transmitted through the panel in an off state.

FIG. 5 is a characteristic diagram showing BV characteristics of the liquid crystal display device.

FIG. 6 is a cross-sectional view showing a schematic configuration of a liquid crystal display panel of the present invention having a color filter layer on at least one substrate.

FIG. 7 is a cross-sectional view showing a schematic configuration of a conventional liquid crystal display panel having a color filter layer on at least one substrate.

FIG. 8 is a sectional view showing a schematic configuration of a conventional liquid crystal display panel.

FIG. 9 is a characteristic diagram showing a liquid crystal material dependency of a transmitted light spectrum in an off state of a conventional liquid crystal display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Glass substrate 12 ... Transparent electrode 13 ... Liquid crystal aligning film 14 ... Spacer and seal resin 15 ... Liquid crystal 16 ... Elliptical polarizing plate 17 ... Color filter layer

Claims (13)

[Claims] 1. A liquid crystal display device comprising an elliptically polarizing plate comprising a polarizing plate and an optical film attached to both sides of a liquid crystal display panel, respectively. The angle between the major axis direction is between 50 and 90 degrees, and the angle between the optical axis direction of one of the light emission side and the incidence side and the major axis direction of the liquid crystal molecules adjacent thereto is: A liquid crystal display device characterized in that the angle is smaller than the angle between the other optical axis direction and the major axis direction of liquid crystal molecules adjacent thereto. 2. The angle between the optical axis direction on the light emission side and the major axis direction of liquid crystal molecules adjacent thereto is defined by the optical axis direction on the light incident side and the major axis direction of liquid crystal molecules adjacent thereto. 2. The liquid crystal display device according to claim 1, wherein the angle is smaller than the angle. 3. An angle between an optical axis direction on the light emission side and a major axis direction of liquid crystal molecules adjacent thereto is defined by an optical axis direction on the light incident side and a major axis direction of liquid crystal molecules adjacent thereto. The liquid crystal display device according to claim 2, wherein the angle is 1 to 10 degrees smaller than the angle. 4. The light emitting side according to claim 1, wherein the angle between the direction of the polarization axis of the polarizing plate and the direction of the optical axis of the optical film is 30 degrees or less on the light emission side.
The liquid crystal display device according to the item. 5. The liquid crystal has a steepness (V50 / V10) of 1.
The liquid crystal display device according to any one of claims 1 to 4, wherein the number is less than 035. 6. The liquid crystal display device according to claim 1, wherein Δn · d of the liquid crystal display panel is less than 0.89. 7. An elliptically polarizing plate comprising a polarizing plate and an optical film is attached to both sides of a liquid crystal display panel, and
A color liquid crystal display device having a color filter on at least one substrate constituting the liquid crystal display panel, wherein a color filter layer is on a light emission side. 8. An angle between an optical axis direction of an optical film and a major axis direction of liquid crystal molecules of a liquid crystal display panel close to the optical axis direction is 5.
0 to 90 degrees, and the angle formed between the optical axis direction of one of the light emitting side and the incident side and the major axis direction of the liquid crystal molecules adjacent thereto is close to the other optical axis direction and adjacent thereto. 8. The liquid crystal display device according to claim 7, wherein the angle between the liquid crystal molecules and the major axis direction of the liquid crystal molecules is smaller. 9. An angle between the optical axis direction on the light emission side and the major axis direction of the liquid crystal molecules adjacent thereto is defined by the optical axis direction on the light incident side and the major axis direction of the liquid crystal molecules adjacent thereto. 9. The liquid crystal display device according to claim 8, wherein the angle is smaller than the angle. 10. An angle between an optical axis direction on the light emission side and a major axis direction of liquid crystal molecules adjacent thereto is defined by an optical axis direction on the light incident side and a major axis direction of liquid crystal molecules adjacent thereto. The liquid crystal display device according to claim 9, wherein the angle is 1 to 10 degrees smaller than the angle. 11. The light emitting side according to claim 7, wherein the angle between the direction of the polarization axis of the polarizing plate and the direction of the optical axis of the optical film is 30 degrees or less. The liquid crystal display device as described in the above. 12. The liquid crystal display device according to claim 7, wherein the sharpness (V50 / V10) of the liquid crystal is less than 1.035.
2. The liquid crystal display device according to claim 1. 13. The Δn · d of the liquid crystal display panel is 0.89.
The liquid crystal display device according to any one of claims 7 to 12, wherein the value is less than the following.