JP2001100204A - Liquid crystal display - Google Patents

Abstract

(57) [Problem] To provide a liquid crystal display device having an optical arrangement in which a high contrast, a high brightness, and an achromatic color can be realized in a well-balanced manner in a structure in which a driving liquid crystal layer and an optical compensation layer are combined. SOLUTION: An STN liquid crystal layer 8 is a display driving liquid crystal layer capable of changing the orientation direction of a twist-aligned liquid crystal polymer, and a twist compensating layer 2 is high in a twist direction opposite to the STN liquid crystal layer 8. Having a structure in which molecules are twisted,
Light from the TN liquid crystal layer 8 is transmitted. Focusing on the relationship between the twist angle の of the STN liquid crystal layer 8 and the twist angle φ of the twist compensating layer 2, by making the twist angle φ smaller than the twist angle χ, high contrast, high brightness, and achromatic display can be balanced. It can be realized well, and good visibility can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device in which a driving liquid crystal layer and an optical compensation layer both having a twist structure are combined.

[0002]

2. Description of the Related Art Liquid crystal display devices are broadly classified into two types, transmission type and reflection type. Since the transmissive type requires a backlight, it is suitable for relatively large display devices.
The reflection type is suitable for a portable terminal device because of low power consumption, light weight, and small size. In addition, there is a transflective liquid crystal display device capable of displaying both a transmissive type and a reflective type.

[0003] Of these, reflective and transflective liquid crystal display devices can be further classified into a type using two polarizing plates and a type using one polarizing plate. In the type using two polarizing plates, the incident light passes through the polarizing plate four times, so that the image is dark. Since a polarizing plate with a reflecting plate needs to be attached to the outside of the lower glass substrate, an image is formed by parallax due to the thickness of the glass. Weight. For this reason, the visibility is significantly reduced. In recent years, in particular, a reflective color liquid crystal display device using a micro color filter has been commercialized. However, if there is the above-mentioned parallax in color, light passes through a color filter of a different color between the outward path and the return path, so that the color Purity decreases. On the other hand, in the type using one polarizing plate, since the incident light passes through the polarizing plate only twice and a reflecting plate can be formed in the cell, it is possible to prevent a reduction in color purity due to double image and color mixing, and the present It is becoming mainstream in mobile terminal devices.

Further, in a liquid crystal display device in which a driving liquid crystal layer for display driving and an optical compensation layer are combined, a driving liquid crystal layer having a twisted structure and an optical compensation having a twisted structure in which the twist direction is opposite to the twisted liquid crystal layer. High contrast is realized by converting linearly polarized light into elliptically polarized light in the driving liquid crystal layer and returning elliptically polarized light to linearly polarized light again in the optical compensation layer. Further, the wavelength dependence due to birefringence is also improved. Hereinafter, a prior art of a liquid crystal display device in which a driving liquid crystal layer and an optical compensation layer are combined will be described.

Japanese Patent Application Laid-Open No. 09-105932 proposes a single-polarizer type liquid crystal display device using an optical compensation layer having a twisted structure. This liquid crystal display device
It is composed of a polarizing plate, a compensation layer, a liquid crystal layer and a reflector. The refractive index anisotropies of the liquid crystal layer and the compensation layer have opposite signs. The twist angle of the sliced liquid crystal layer / compensation layer when the liquid crystal layer and compensation layer when no voltage is applied or when an arbitrary voltage is applied is sliced in the thickness direction in which the direction of the long axis of the liquid crystal molecule can be regarded as a substantially constant direction. , And they are almost the same. This is the same as the design method of the double cell structure.

Japanese Patent Application Laid-Open No. 08-076111 also proposes a single-polarizer type liquid crystal display device using an optical compensation layer having a twisted structure. In this liquid crystal display device, a liquid crystal layer for driving and a liquid crystal layer having a twisted structure in the opposite direction for optical compensation are laminated, and a polarizing plate 6 is arranged on one of the outside of them and a reflector is arranged on the other. , Δn · d of the two liquid crystal layers is set to 700 nm or more.

Japanese Patent Application Laid-Open No. 11-072784 proposes a liquid crystal display device of a two-polarizer type using a twisted phase difference plate having a twisted structure. In this liquid crystal display device, a twisted phase difference plate is disposed between a pair of polarizing plates, and the absolute value of the twist angle of the twisted phase difference plate is set to be 5 to 30 degrees larger than the absolute value of the twist angle of the liquid crystal element. I have.

[0008]

However, including the optical arrangement proposed in the above-mentioned publication, the optical arrangement of a reflection type liquid crystal display device of a single polarizing plate type using an STN type liquid crystal conventionally proposed includes: Optimization of optical compensation is incomplete, and brightness, contrast, and color tone cannot be optimized in a well-balanced manner.

An object of the present invention is to provide a liquid crystal display device having an optical arrangement capable of achieving high contrast, high brightness and achromatic color in a well-balanced structure in which a driving liquid crystal layer and an optical compensation layer are combined.

[0010]

According to the present invention, there is provided a driving liquid crystal layer for driving a display capable of changing the orientation direction of a twisted liquid crystal polymer, and a polymer in a twist direction opposite to the driving liquid crystal layer. A liquid crystal display device having an optical compensation layer that transmits light from the driving liquid crystal layer and has a structure in which:
The twist angle of the optical compensation layer is smaller than the twist angle of the driving liquid crystal layer.

According to the present invention, attention is paid to the relationship between the twist angle の of the driving liquid crystal layer and the twist angle φ of the optical compensation layer, and by making the twist angle φ smaller than the twist angle χ, high contrast and high brightness can be achieved. Achromatic display can be realized in a well-balanced manner, and good visibility can be obtained.

The present invention also provides a driving liquid crystal layer for driving a display capable of changing the alignment direction of a twisted liquid crystal polymer,
An optical compensation layer that has a structure in which polymers are twisted in a twist direction opposite to the driving liquid crystal layer and transmits light from the driving liquid crystal layer, and a light reflection layer disposed on the back side of the driving liquid crystal layer, A polarizing layer disposed on the front side of the optical compensation layer,
The twist angle of the optical compensation layer is smaller than the twist angle of the driving liquid crystal layer.

According to the present invention, in a reflective or semi-transmissive liquid crystal display device in which a single polarizing layer, an optical compensation layer, a driving liquid crystal layer, and a light reflection layer are sequentially laminated, as described above, By making the twist angle φ smaller than the twist angle の of the driving liquid crystal layer, high contrast, high brightness and achromatic display can be realized in a well-balanced manner, and good visibility can be obtained.

Further, in the present invention, the twist angle of the driving liquid crystal layer is in the range of 220 to 260 degrees, and the twist angle of the optical compensation layer is one more than the twist angle of the driving liquid crystal layer.
It is characterized by being smaller by 0 to 130 degrees.

According to the present invention, by setting the twist angle の of the driving liquid crystal layer to 220 degrees or more, excellent steepness of electro-optical characteristics can be ensured.
High contrast can be secured. The twist angle χ is 2
When the angle is set to 60 degrees or less, the orientation can be ensured well, so that it is sufficiently practical. Further, the twist angle φ of the optical compensation layer is set to be 10 degrees to 1
By reducing the angle by 30 degrees, higher contrast can be obtained.

Further, the present invention is characterized in that the retardation of the optical compensation layer is in a range of 400 nm to 900 nm.

According to the present invention, higher contrast can be obtained by setting the retardation Rc of the optical compensation layer in the range of 400 nm to 900 nm.

Further, in the present invention, the retardation of the driving liquid crystal layer is in a range of 660 nm to 960 nm.

According to the present invention, a higher contrast can be obtained by setting the retardation Rd of the driving liquid crystal layer in the range of 660 nm to 960 nm.

Further, in the present invention, the retardation Rc of the optical compensation layer and the retardation Rd of the driving liquid crystal layer are represented by-
It is characterized by satisfying 300 nm <Rc-Rd <0 nm.

According to the present invention, -300 nm <Rc-R
By setting d <0 nm, higher contrast can be obtained.

Further, according to the present invention, when the twist direction of the liquid crystal polymer arranged from the back side to the front side of the driving liquid crystal layer is positive, the length of the liquid crystal polymer positioned at the back side end of the optical compensation layer is improved. The axis is oriented in a direction obtained by rotating the major axis of the liquid crystal polymer positioned at the front end of the driving liquid crystal layer by -65 degrees to -100 degrees.

According to the present invention, the rotation angle θ from the alignment direction on the front side of the driving liquid crystal layer to the alignment direction on the back side of the optical compensation layer is in the range of −65 ° to −100 °. And higher contrast can be obtained.

Further, according to the present invention, when the twist direction of the liquid crystal polymer arranged from the back side to the front side of the driving liquid crystal layer is positive, the absorption axis of the polarizing plate is located at the front end of the optical compensation layer. The long axis of the positioned liquid crystal polymer is -30 degrees to +25.
3. The liquid crystal device according to claim 2, wherein the liquid crystal is oriented in a direction rotated by degrees.
The liquid crystal display device as described in the above.

According to the present invention, the rotation angle の from the orientation direction on the front surface side of the optical compensation layer to the absorption axis direction of the polarizing layer is defined by:
By setting the angle in the range of -30 degrees to +25 degrees, higher contrast can be obtained.

Further, the present invention is characterized in that the optical compensation layer is a twisted retardation plate obtained by solidifying a liquid crystal polymer in a twisted state.

According to the present invention, the weight can be reduced by using a twisted retardation plate obtained by solidifying a liquid crystal polymer.

Further, the present invention is characterized in that a light-shielding black matrix is provided between pixel electrodes for driving the driving liquid crystal layer for each pixel.

According to the present invention, it is possible to improve the contrast at the time of reflection and transmission by shielding the space between the pixel electrodes with a black matrix.

Further, the present invention is characterized in that the driving liquid crystal layer is sandwiched between a pair of transparent substrates made of synthetic resin.

According to the present invention, by making the light-transmitting substrate made of synthetic resin, the weight can be reduced and the impact resistance can be improved.

The present invention is also characterized in that the light reflecting layer transmits circularly polarized light from the back.

According to the present invention, by using a material that transmits circularly polarized light from the back as the light reflecting layer, a backlight can be arranged on the back side of the light reflecting layer, so that there is no external light. However, a transflective liquid crystal display device capable of displaying can be realized. In this case, since the incident light passes through the driving liquid crystal layer only once and is emitted, circular polarization may be incident on the light reflection layer.

[0034]

FIG. 1 is a sectional view showing the structure of a liquid crystal display device according to an embodiment of the present invention. From the front side where light enters, a polarizing plate 1, a twist type compensation layer (optical compensation layer) 2, a forward scattering plate 3, an upper glass substrate 4, a transparent electrode 5, an alignment film 7, an STN liquid crystal layer (driving liquid crystal layer) 8 , Alignment film 7, transparent electrode 5, overcoat layer 9, color filter 1
The liquid crystal display device is formed by laminating the reflection function layer 11 and the lower glass substrate 12 in this order.

Aluminum is vapor-deposited on the lower glass substrate 12 to form the reflection function layer 11, and RGB is formed thereon by an electrodeposition method.
Are formed.
An acrylic resin-based overcoat layer 9 is formed on the color filter 10, so that unevenness due to the overlapping portion of the color filter surface and the difference in film thickness of each color can be smoothed, and a decrease in orientation can be prevented.

The upper transparent electrode 5 is formed on the upper glass substrate 4 and the lower transparent electrode 5 is formed on the overcoat layer 9 by depositing and etching ITO (indium tin oxide). It is a matrix-shaped pixel electrode. A black matrix may be formed of a light-absorbing substance around the pixel electrode, and by doing so, the black shielding power at the time of reflection and transmission can be improved, thereby contributing to higher contrast.

In FIG. 1, the color filter 10 is formed on the lower glass substrate 12 side, but there is no problem if it is formed on the upper glass substrate 4 side. At this time, the transparent electrode 5 on the lower glass substrate 12 may be replaced with a metal electrode having a reflection effect.

The alignment film 7 is formed by applying polyimide on the transparent electrode 5 by printing and baking. Rubbing treatment is performed on the alignment film 7 so that the liquid crystal molecules are aligned at a twist angle χ = 220 degrees to 260 degrees.
(If the twist angle 未 満 is less than 220 degrees, the sharpness of the electro-optical characteristics deteriorates, so that the contrast cannot be ensured, especially in a simple matrix drive.
If it exceeds the degree, the orientation deteriorates and is not suitable for practical use. After bonding the upper and lower substrates with the sealing resin 6, liquid crystal whose birefringence Δn and pitch have been adjusted is injected to form an STN liquid crystal cell. The cell thickness may be, for example, 6 μm, but is not limited thereto and may be determined as appropriate.

The forward scattering plate 3 is attached on the upper glass substrate 4 of the cell thus formed. Forward scattering plate 3
Has a function to change the traveling direction of light by scattering,
Since light in the direction other than the specular reflection direction is also observed, the display can be brightened. In addition, since the polarization is not disturbed, the contrast is not reduced, and the display is prevented from being blurred due to parallax by being placed as close to the reflector as possible.

On top of this, the desired retardation Rc (= d
Δn) and a predetermined twist angle φ, Δn = 0.219, and a twist-type compensation layer 2 of a high-molecular polymer type manufactured by Nisseki Petrochemical Co., Ltd., and a neutral gray polarizing plate 1 (manufactured by Nitto Denko Corporation). It is attached to the liquid crystal cell so as to have a predetermined axis.

In this case, the sticking type forward scattering plate 3
(Nitto Denko Corporation) is used, but the same effect can be obtained by forming a scattering layer in the cell or making the reflection function layer 11 have a function of diffusing reflected light.

Although a glass substrate is used here, a liquid crystal display device may be manufactured using a plastic substrate. By making the substrate made of plastic in this way, the weight can be reduced and the impact resistance can be improved.

Although a color liquid crystal display device using a color filter is described here as an embodiment, the present invention can be applied to a monochrome liquid crystal display device without a color filter.

In the liquid crystal display device configured as shown in FIG. 1, light incident on the polarizing plate 1 from the surroundings is converted into linearly polarized light by the polarizing plate 1, and is converted into elliptically polarized light through the torsional compensation layer 2. Are modulated by the STN liquid crystal layer 8 and reflected by the reflection function layer 11. The reflected light then travels in the opposite direction, undergoes modulation, exits, and is observed.

What is important for the liquid crystal display device is that the intensity ratio of the emitted light is largely modulated in the entire visible light wavelength region by the voltage applied to the STN liquid crystal layer 8. When displaying the reflected light in white, the birefringence phase difference between the reflection function layer 11 and the polarizing plate 1 is set to λ / 2 or λ, and the reflection function layer 11
At this point, the light may be converted into linearly polarized light. When displaying black, the birefringence phase difference may be set to λ / 4 or 3λ / 4 and converted into circularly polarized light at the reflection function layer 11. That is, by applying a voltage to the STN liquid crystal layer 8, the phase difference is changed from λ or λ / 2 to λ / 4 or 3λ.
/ 4 can be modulated over the entire wavelength range, and high contrast, high brightness, and achromatic color can be realized.

Although a reflection type liquid crystal display device using ambient light is used here, a front light type liquid crystal display device or a transflective type liquid crystal display device described later may be used.

Further, the normally black mode in which the liquid crystal molecules are laid down (twisted) and the normally black mode in which the dark display is obtained, as compared with the normally white mode in which the dark display is obtained with the liquid crystal molecules set up, In the present embodiment, driving is performed in a normally black mode because dark display is easily compensated and good black display is easily obtained. As a result, high contrast can be obtained.

FIG. 2 shows a diagram defining the axial angles of the respective optical elements in the present embodiment. The twist angle of the liquid crystal molecules from the orientation direction 13 of the long axis of the liquid crystal molecules on the lower glass substrate 12 side of the STN liquid crystal 8 to the orientation direction 14 of the long axis of the liquid crystal molecules on the upper glass substrate 4 is defined as the twist angle χ (chi). And the twisting direction is positive. The angle of the major axis direction 15 of the lower molecule of the twist type compensation layer 2 with respect to the upper substrate side alignment direction 14 of the major axis of the liquid crystal molecule is θ, and the angle of the lower molecule major axis direction 15 of the twist compensator 2 is The angle twisted up to the upper molecular long axis direction 16 is φ, and the angle of the absorption axis direction 17 of the polarizing plate 1 with respect to the upper molecule long axis direction 16 of the twist compensation layer 2 is ψ.

The parameters for forming the optical element in the liquid crystal display element include the polarizing plate axis angle ψ and the twist type compensation layer 2.
, The twist angle φ and the axis angle θ, the retardation Rd of the STN liquid crystal layer 8, and the twist angle χ. lead. The results are described below.

However, the light having a wavelength of 550 nm is used for measuring the retardation Rc of the twist compensation layer 2, and the wavelength of 589 nm is used for measuring the retardation Rd of the STN type liquid crystal layer 8.
Was used.

FIGS. 3 (1), 3 (2), 4 (1), 4 (2), and 5 show twist angles χ = 220 degrees and 230 degrees.
It is a graph which respectively shows the relationship between the twist angle (phi) and contrast value Co at the time of 240 degrees, 250 degrees, and 260 degrees. The horizontal axis indicates the twist angle φ of the twist compensation layer 2, and the vertical axis indicates the contrast value Co. The graph is a plot of combinations of the above parameters where the contrast value Co is 100 or more and the reflectance L (brightness) is 40% or more. Normally, the reflectance L is 40%
It is said that there is no problem in practical use if it is above.

From these figures, it can be seen that a higher contrast liquid crystal display device can be obtained when the twist angle φ of the twisted optical compensation layer 2 is smaller than the twist angle の of the liquid crystal molecules of the STN type liquid crystal layer 8. In addition, the twist optical compensation layer 2
When the twist angle φ and the twist angle の of the liquid crystal molecules of the STN type liquid crystal layer 8 were made the same, the conditions under which the contrast value Co was good were the following two conditions. That is, STN
When the twist angle の of the liquid crystal layer 8 is 220 degrees and the twist angle φ of the twisted optical compensation layer 2 is 220 degrees, the contrast C
o = 109.7, reflectance L = 45.97%, ST
When the twist angle の of the N liquid crystal layer 8 was 240 degrees and the twist angle φ of the twisted optical compensation layer 2 was 240 degrees, the contrast Co was 105.5 and the reflectance L was 41.05%.

FIGS. 6A and 6B show that the reflectance is 40.
% And twist angle χ and | φ |-|
It is a graph each showing the relationship with χ |. The horizontal axis is S
The twist angle χ [degree] of the TN liquid crystal layer 8 is shown, and the vertical axis is |
φ | − | χ | (degree). The graph is plotted by classifying into contrast values Co>200,> 150, and> 110. The reason for Co> 110 is | φ
The maximum contrast Co when | = | χ | is 109.7.
Because it was.

Since | φ | = | χ | and the maximum reflectance of Co> 100 was 45.97%, from FIG.
With respect to the twist angle の of the N liquid crystal layer 8, the twist type compensation layer 2
Is 10 to 130 degrees, preferably 40 to
100 degrees, more preferably, from 60 to 60 degrees from FIG.
It can be seen that it should be smaller by about 100 degrees (empirically ± 5 degrees).

In particular, when the twist angle の of the STN liquid crystal layer 8 is 2
When the angle is 20 degrees, the twist angle φ of the torsion compensation layer 2 is set to 4
The angle may be reduced by 0 to 100 degrees, preferably about 60 degrees. When the twist angle の of the liquid crystal layer 8 is 230 degrees, the twist angle φ of the twist compensation layer 2 may be reduced by 10 to 110 degrees, preferably about 70 degrees. When the twist angle の of the liquid crystal layer 8 is 240 degrees, the twist angle φ of the twist compensation layer 2
May be reduced by about 20 to 120 degrees, preferably about 40 to 100 degrees, and more preferably about 60 to 100 degrees. When the twist angle の of the liquid crystal layer 8 is 250 degrees, the twist angle φ of the twist compensation layer 2 is 30 to 130 degrees, preferably 50 to 130 degrees.
The angle may be reduced by 90 degrees, more preferably about 70 to 90 degrees. When the twist angle の of the liquid crystal layer 8 is 260 degrees,
The twist angle φ of the torsion compensation layer 2 is 60 to 120 degrees, preferably 60 to 100 degrees, and more preferably 80 to 100 degrees.
What is necessary is just to make it small about degree.

FIGS. 7 (1), 7 (2), 8 (1), 8 (2) and 9 show a twist angle χ = 220 degrees and 230
It is a graph which shows the relationship between twist angle (phi) and retardation Rc at the time of 240 degree, 250 degree, and 260 degree, respectively. The horizontal axis is the twist angle φ of the twist compensation layer 2.
[Degree], the vertical axis represents the retardation Rc of the twist compensation layer 2
[Nm].

FIGS. 10 (1) and 10 (2) show the reflectance L
Is a graph showing the relationship between the twist angle φ and the retardation Rc when the angle is 40% or more and 46% or more. The horizontal axis is
The twist angle φ of the torsion compensation layer 2 is shown, and the vertical axis represents the retardation Rc of the torsion compensation layer 2. The graph is obtained by classifying and plotting the contrast values when Co>200,> 150, and> 110.

FIG. 10A shows that the retardation value Rc of the twist compensation layer 2 is 400 to 900 nm (particularly φ: 120 to 220) with respect to the twist angle φ of the twist compensation layer 2.
Degree), preferably 450 to 900 nm (especially φ: 140
~ 200 degrees), and more preferably, from FIG.
It can be seen that it is appropriate to optimize appropriately within a range of about 500 to 900 nm (particularly φ: 140 to 180 degrees) (empirically ± 50 nm).

FIG. 7A shows that when the twist angle 特 に of the liquid crystal layer 8 is 220 degrees, 550 to 800 nm (especially φ: 120 to 180 degrees), preferably 750 to 800 n
m (especially φ: around 160 degrees). FIG.
From (2), particularly, when the twist angle の of the liquid crystal layer 8 is 230 degrees, 400 to 900 nm (especially φ: 120 to 22 nm)
0 degree), preferably 850 to 900 nm (particularly φ: 16
(Around 0 degrees). From FIG. 8A, in particular,
400 to 9 when the twist angle の of the liquid crystal layer 8 is 240 degrees
00 nm (especially φ: 120 to 220 degrees), preferably 4
The thickness may be about 50 to 900 nm (especially φ: 140 to 200 degrees). From FIG. 8 (2), particularly, when the twist angle の of the liquid crystal layer 8 is 250 degrees, 400 to 900 nm (especially φ: 120 to 220 degrees), preferably 450 to 750 n
m (especially φ: 160 to 200 degrees). From FIG. 9, particularly, when the twist angle の of the liquid crystal layer 8 is 260 degrees, 500 to 900 nm (especially φ: 140 to 200 nm)
Degree), preferably 500 to 600 nm (especially φ: 160
~ 200 degrees) or 850-900 nm (especially φ:
(Around 180 degrees).

FIG. 11 (1), FIG. 11 (2), FIG.
(1), FIG. 12 (2), and FIG. 13 show the twist angle χ = 22.
It is a graph which shows the relationship between the twist angle (phi) and retardation Rd at 0 degree, 230 degree, 240 degree, 250 degree, and 260 degree, respectively. The horizontal axis shows the twist angle φ [degree] of the twist compensation layer 2 and the vertical axis shows the retardation value Rd [nm] of the STN type liquid crystal layer 8.

FIGS. 14 (1) and 14 (2) show the reflectance L
Is a graph showing the relationship between the twist angle φ and the retardation Rd when the angle is 40% or more and 46% or more. The horizontal axis is
The twist angle φ of the twist compensation layer 2 is shown, and the vertical axis is STN
3 shows a retardation value Rd [nm] of the liquid crystal layer 8. The graph shows contrast values Co>200,>150,> 1.
It is classified at the time of 10 and plotted respectively.

FIG. 14A shows that the retardation Rd of the STN type liquid crystal layer 8 is 660 to 960 nm (especially φ: 120 to 220) with respect to the twist angle φ of the twist compensating layer 2.
Degree), and more preferably, from FIG.
It can be seen that it is sufficient to set it to about 960 nm (especially φ: 140 to 180 degrees) (empirically ± 10%).

In particular, from FIG. 11A, when the twist angle 液晶 of the liquid crystal layer 8 is 220 degrees, 720 to 900 nm (especially φ: 120 to 180 degrees), preferably 840 to 900 nm
nm (especially φ: around 160 degrees). FIG.
From 1 (2), in particular, the twist angle の of the liquid crystal layer 8 is 230
At 660 to 960 nm (especially φ: 120 to 2
20 °), preferably 900 to 960 nm (especially φ: 1).
(Around 60 degrees). From FIG. 12A, especially when the twist angle の of the liquid crystal layer 8 is 240 degrees, 66
The thickness may be about 0 to 960 nm (especially φ: 120 to 220 degrees). From FIG. 12 (2), particularly, when the twist angle の of the liquid crystal layer 8 is 250 degrees, 660 to 960 nm (especially φ: 120 to 220 degrees), preferably 660 to 840 n
m (especially φ: 160 to 200 degrees). From FIG. 13, particularly, when the twist angle の of the liquid crystal layer 8 is 260 degrees, 660 to 960 nm (especially φ: 140 to 200 nm)
Degrees), preferably 720-960 nm (especially φ: 160
(About 200 degrees).

FIG. 15A is a graph showing the relationship between the retardation Rd and the retardation Rc when the reflectance L is 40% or more. FIG.
It is a graph which shows the relationship between retardation Rd and Rc-Rd at 6% or more. The horizontal axis is shown in FIG.
5 (2), the retardation Rd of the STN liquid crystal layer 8
[Nm]. The vertical axis indicates the retardation Rc [nm] of the twist compensation layer 2 in FIG.
(2) shows Rc-Rd [nm]. The graph is plotted by classifying the contrasts into Co>200,> 150, and> 110.

FIG. 15B shows that the retardation Rc of the twist compensation layer 2 and the retardation R of the STN type liquid crystal layer 8 are different.
d means -300 <Rc-Rd <0 [nm], preferably -230≤Rc-Rd≤-50 (empirically ± 10%)
It can be seen that it is sufficient to satisfy [nm].

FIG. 16 (1), FIG. 16 (2), FIG.
(1), FIG. 17 (2), and FIG. 18 show the twist angle χ = 22.
It is a graph which shows the relationship between twist angle (phi) and angle (theta) at 0 degree, 230 degree, 240 degree, 250 degree, and 260 degree, respectively. The horizontal axis is the twist angle φ [degree] of the twist compensation layer 2
The vertical axis represents the upper substrate side alignment direction 1 of the liquid crystal molecule long axis.
4 shows the angle θ [degree] of the lower molecule in the major axis direction 15 of the twist type compensation layer 2 with reference to 4.

FIGS. 19 (1) and 19 (2) show the reflectance L
Is a graph showing the relationship between the twist angle φ and the angle θ when the angle θ is 40% or more and 46% or more. The horizontal axis indicates the twist angle φ of the twist compensation layer 2, and the vertical axis indicates the angle θ. The graph shows contrast values Co>200,> 150, and> 11.
The plots are classified into 0 and plotted.

As shown in FIG. 19A, the angle θ is −65 to −100 degrees (particularly φ: 120 to 220 degrees), preferably −75 to −90 degrees with respect to the twist angle φ of the torsion compensation layer 2. In particular, φ: 140 to 200 degrees, and more preferably, from FIG.
It can be seen that optimization may be appropriately performed within a range of about (180 degrees) (experimentally ± 5 degrees).

FIG. 16A shows that, when the twist angle の of the liquid crystal layer 8 is 220 degrees, -80 to -90 degrees (especially φ: 120 to 180 degrees), preferably -85 to -90 degrees (Especially φ: around 160 degrees). FIG.
From (2), particularly, when the twist angle の of the liquid crystal layer 8 is 230 degrees, −65 to −90 degrees (particularly φ: 120 to 220 degrees)
Degrees), preferably around -90 degrees (especially φ: around 160 degrees). FIG. 17A shows that the liquid crystal layer 8
Is −65 to −90 degrees (especially φ: 120 to 220 degrees), preferably −75 to −90 degrees.
The angle may be about 90 degrees (especially φ: 140 to 200 degrees). From FIG. 17B, in particular, the twist angle of the liquid crystal layer 8 χ
Is -65 to -100 degrees (especially φ: 1
20 to 220 degrees), preferably about -75 to -85 degrees (especially φ: 160 to 200 degrees). From FIG. 18, especially, when the twist angle の of the liquid crystal layer 8 is 260 degrees, −75 to −95 degrees (especially φ: 140 to 200 degrees),
Preferably -75 to -90 degrees (especially φ: 160 to 200
Degree).

FIGS. 20 (1), 20 (2), 21
(1), FIG. 21 (2), and FIG. 22 show the twist angle χ = 22.
It is a graph which shows the relationship between twist angle (phi) and angle (psi) at 0 degree, 230 degree, 240 degree, 250 degree, and 260 degree, respectively. The horizontal axis is the twist angle φ [degree] of the twist compensation layer 2
The vertical axis indicates the angle ψ [degree] of the absorption axis 17 of the polarizing plate 1 with respect to the major axis direction 16 of the molecule above the twist compensation layer 2.

FIGS. 23 (1) and 23 (2) show the reflectance L
Is a graph showing the relationship between the twist angle φ and the angle ψ when is 40% or more and 46% or more. The horizontal axis indicates the twist angle φ of the twist compensation layer 2, and the vertical axis indicates the angle ψ. The graph shows contrast values Co>200,> 150, and> 11.
The plots are classified into 0 and plotted.

FIG. 23A shows that the angle ψ is -30 to 25 degrees with respect to the twist angle φ of the twist compensation layer 2 (particularly, φ:
120 to 220 degrees), preferably -20 to 25 degrees (especially φ: 140 to 200 degrees), and more preferably FIG.
From (2), -20 to -15 degrees (especially φ: 140 to 16
0 degree) or 20 to 25 degrees (especially φ: 160 to 180)
Degrees) (experimentally ± 5 degrees).

FIG. 20 (1) shows that, especially when the twist angle の of the liquid crystal layer 8 is 220 degrees, it is -25 degrees or 20 to 20 degrees.
25 degrees (especially φ: 120 to 180 degrees), preferably 25 degrees
Degree (especially φ: around 160 degrees). FIG.
From (2), especially when the twist angle χ of the liquid crystal layer 8 is 230 degrees, it is −30 to −15 degrees or 15 to 25 degrees (particularly φ: 120 to 220 degrees), preferably 25 degrees (particularly φ: (Around 160 degrees). From FIG. 21A, particularly, when the twist angle の of the liquid crystal layer 8 is 240 degrees, −25 degrees to 25 degrees (especially φ: 120 to 220 degrees);
Preferably, it may be about -20 to -15 degrees or about 15 to 25 degrees (particularly, φ: around 140 to 200 degrees). FIG.
From 1 (2), especially when the twist angle of the liquid crystal layer is 250 degrees, −25 degrees to 25 degrees (especially φ: 120 to 220 degrees)
Degrees), preferably -15 to 20 degrees (especially φ: 160 to 2
00 degrees). From FIG. 22, especially, when the twist angle of the liquid crystal layer is 260 degrees, −25 degrees to 25 degrees (especially φ: 140 to 200 degrees), preferably −15 degrees to −5 degrees or 10 to 20 degrees (particularly, φ: (160-200 degrees).

FIG. 24 is a diagram showing a display principle of a transflective liquid crystal display device according to another embodiment of the present invention. The transflective liquid crystal display device includes circularly polarized light selective irradiation means for selectively irradiating circularly polarized light toward the reflection means on the opposite side of the reflection type liquid crystal display device from the liquid crystal cell of the reflection means. And the reflection means has a function of transmitting a part of light. In the case of the liquid crystal display device shown in FIG.
Circularly polarized light selective irradiating means is arranged on the side opposite to the STN liquid crystal layer 8, and the reflective layer 11 transmits a part of the light. The reflection layer 21 corresponds to the reflection function layer 11 in FIG.

More specifically, the circularly polarized light selective irradiation means is composed of a λ / 4 plate 22 and a polarizing plate 23 which are sequentially arranged on the rear side of the translucent substrate 12. The circularly polarized light selective irradiation means is composed of a cholesteric film 24 disposed on the back side of the translucent substrate 12.

The circularly polarized light selected by the circularly polarized light selective irradiating means, which is irradiation light from the backlight 25, for example, on the opposite side of the liquid crystal cell of the circularly polarized light selective irradiating means, passes through the transflective reflective layer 21. The light passes through to become circularly polarized light. When an off-voltage is applied (during black display), the circularly polarized light is modulated by the liquid crystal cell, becomes linearly polarized light by the torsional compensation layer 2, and is absorbed by the polarizing plate 1. When applying ON voltage (white display),
The circularly polarized light is modulated by the liquid crystal cell, becomes elliptically polarized light by the twist type compensation layer 2, and partially transmits through the polarizing plate 1.

At this time, the rotation direction of the circularly polarized light selected by the circularly polarized light selection means is the same as the rotation direction after the light incident from the polarizing plate side when the off voltage is applied (during black display) is reflected by the reflective layer 21. It is necessary to set to the same direction. In this way, when an off-voltage is applied (during black display), the light enters from the upper polarizing plate 1 side, is reflected by the reflective layer 21 and the light enters from the lower polarizer 23 and passes through the reflective layer 21. Are both absorbed by the upper polarizing plate 1, and a stable black display is possible.

In this way, a transmissive display can be realized instead of the reflective display as described above. This enables display even when ambient light is weak or when there is no ambient light.

The circularly polarized light selecting means is composed of the λ / 4 plate 22 and the polarizing plate 2
3, the incident light becomes linearly polarized light by the polarizing plate 23 and becomes circularly polarized light by the λ / 4 plate 22. Also,
When the circularly polarized light selective irradiating means is composed of the cholesteric film 24, one of clockwise light and counterclockwise light is transmitted by the cholesteric film 24, the other is reflected, and the light incident from the reflective layer side is reflected. Circularly polarized light can be obtained.

Hereinafter, the liquid crystal display device according to the present invention will be described in detail with reference to examples. (Example 1) Retardation Rd of STN liquid crystal layer 8 = 8
00 nm, Rc of the torsional compensation layer 2 = 650 nm, χ =
With 220 degrees, θ = −90 degrees, φ = −180 degrees, and ψ = 25 degrees, high contrast, high brightness, and achromatic color can be realized with good balance.

In irradiation with diffused light, 1/240 dut
By a simple matrix drive of y, 1 / 13bias, a characteristic right above obtained a characteristic having a contrast of 8 and a reflectance of 11%. The chromaticity at the chromaticity coordinates xy in the XYZ color system when displaying white and black is white (x, y) = (0.3
1, 0.33), black (x, y) = (0.29, 0.2
8) It is close to the white point, and the intermediate colors are practically sufficiently achromatic, so that high contrast, high brightness, and achromatic colors can be realized in a well-balanced manner.

In addition, by using a half mirror to enter circularly polarized light from the back side, a contrast of 17 and a transmittance of 1.8% are realized in the transmission mode, realizing high contrast, high transmission, achromatic color and good display quality. it can.

The contrast was measured as follows. That is, as the light source, diffused light is used, and
The reflectance of the reflected light from the light irradiation region of m diameter to the range of the viewing angle of 2 degrees was measured. The reflectance at the time of ON voltage is Lon, the reflectance at the time of OFF voltage is Loff, and Lon / Lo
The maximum value of ff was defined as the contrast. The color tone was evaluated in the CIE chromaticity space for the same reflected light as described above. The retardation of the twist compensation layer 2 and the STN liquid crystal layer 8 was measured by a rotation analyzer method (the measurement wavelengths used were: compensation layer 2: 550 nm, liquid crystal layer 8: 5).
It was 89 nm. ). In particular, the retardation of the liquid crystal layer 8 was measured with no voltage applied. The measurement was performed in the same manner in the following examples.

(Example 2) The retardation Rd of the STN liquid crystal layer 8 was 850 nm, the retardation Rc of the twist type compensation layer 2 was 700 nm, χ = 230 degrees, θ = −90 degrees,
With φ = −180 degrees and ψ = 25 degrees, high contrast, high brightness, and achromatic color can be realized with good balance.

In the diffused light irradiation, 1/240 duty,
With a simple matrix drive of 1 / 13bias, a characteristic right above obtained a contrast of 8 and a reflectance of 10.5%. The chromaticity at the chromaticity coordinates xy in the XYZ color system when displaying white and black is white (x, y) = (0.3
1, 0.32), black (x, y) = (0.29, 0.2
8) It is close to the white point, and the intermediate colors are practically sufficiently achromatic, so that high contrast, high brightness, and achromatic colors can be realized in a well-balanced manner.

Also, in the transmission mode, high contrast, high transmission, achromatic color, and good display quality can be achieved by transmitting circularly polarized light from the back side using a half mirror even in the transmission mode. realizable.

(Embodiment 3) The retardation Rd of the STN liquid crystal layer 8 is 850 nm, the retardation Rc of the twist compensation layer 2 is 750 nm, χ = 240 degrees, θ = −95 degrees,
With φ = −175 degrees and ψ = 20 degrees, high contrast, high brightness, and achromatic color can be realized with good balance.

In irradiation of diffused light, 1/240 dut
By a simple matrix drive of y and 1 / 13bias, the characteristics right above obtained a contrast of 8 and a reflectance of 10%. The chromaticity at the chromaticity coordinates xy in the XYZ color system when displaying white and black is white (x, y) = (0.3
2, 0.32), black (x, y) = (0.31, 0.2)
9), which is close to the white point, and the intermediate color is practically sufficiently achromatic, so that high contrast, high brightness, and achromatic color can be realized in a well-balanced manner.

Also, by using a half mirror to enter circularly polarized light from the back side, even in the transmission mode, the contrast is 18, the transmittance is 1.7%, and high contrast, high transmission, achromatic color and good display quality are obtained. realizable.

Further, at this time, in the cell in which the gap between the electrodes was shielded by the black matrix, the contrasts at the time of reflection and transmission were 9.5 and 30, respectively, and it was confirmed that this greatly contributed to high contrast.

When a plastic substrate was used, characteristics of a contrast of 8 and a reflectance of 10% were obtained, and it was confirmed that characteristics comparable to those of a glass substrate were obtained.

(Embodiment 4) The retardation Rd of the STN liquid crystal layer 8 is 850 nm, the retardation Rc of the twist compensation layer 2 is 750 nm, χ = 250 degrees, θ = −95 degrees,
With φ = −175 degrees and ψ = 20 degrees, high contrast, high brightness, and achromatic color can be realized with good balance.

In irradiation with diffused light, 1/240 dut
With a simple matrix drive of y and 1/13 bias, the characteristics right above obtained a characteristic of a contrast of 8 and a reflectance of 10%. The chromaticity at the chromaticity coordinates xy in the XYZ color system when displaying white and black is white (x, y) = (0.
31, 0.32), black (x, y) = (0.28, 0.2
8) It is close to the white point, and the intermediate colors are practically sufficiently achromatic, so that high contrast, high brightness, and achromatic colors can be realized in a well-balanced manner.

Also, in the transmission mode, a contrast of 17 and a transmittance of 1.7% are obtained in the transmission mode by using a half mirror to input circularly polarized light from the back side, and high contrast, high transmission, achromatic color, and good display quality are achieved. Can be realized.

(Embodiment 5) The retardation Rd of the STN liquid crystal layer 8 is 900 nm, the retardation Rc of the twist type compensation layer 2 is 800 nm, χ = 260 degrees, θ = −90 degrees,
With φ = −180 degrees and ψ = 20 degrees, high contrast, high brightness, and achromatic color can be realized with good balance.

In irradiation with diffused light, 1/240 dut
With a simple matrix drive of y and 1/13 bias, the characteristics right above obtained a characteristic of a contrast of 8 and a reflectance of 10%. The chromaticity at the chromaticity coordinates xy in the XYZ color system when displaying white and black is white (x, y) =
(0.32, 0.32), black (x, y) = (0.29,
0.29), which is close to the white point, and the intermediate colors are practically sufficiently achromatic, so that high contrast, high brightness, and achromatic colors can be realized in a well-balanced manner.

Also, by using a half mirror to enter circularly polarized light from the back side, in the transmission mode, the contrast is 17, the transmittance is 1.7%, and high contrast, high transmission, achromatic color and good display quality are obtained. realizable.

As described above, in any of the embodiments, it is possible to improve the contrast at the time of reflection and transmission by shielding the space between the pixel electrodes with the black matrix. Further, even when a plastic substrate is used, characteristics equivalent to those of a glass substrate can be obtained, and the substrate can be appropriately selected depending on the application.

Even if the angle ψ is shifted by 90 degrees, the same effect can be obtained due to the symmetry of the optical arrangement.

In this case, d △ n is adjusted by adjusting the thickness of the liquid crystal of the twist compensation layer 2 by using a material of Δn = 0.219, but the wavelength dispersion is appropriately adjusted by using materials having different Δn. It is advisable to adjust according to the driving cell.

[0101]

As described above, according to the present invention, attention is paid to the relationship between the twist angle の of the driving liquid crystal layer and the twist angle φ of the optical compensation layer, and the twist angle φ is made smaller than the twist angle χ. , High contrast, high brightness, and achromatic display can be realized in a well-balanced manner, and good visibility can be obtained.

The twist angle 液晶 of the driving liquid crystal layer is set to 220
By setting the degree or higher, the steepness of the electro-optical characteristics can be favorably secured, and high contrast can be secured particularly in simple matrix driving. Further, by setting the twist angle ２６０ to 260 degrees or less, good orientation can be ensured, and a practical level liquid crystal display device can be realized. Further, the twist angle φ of the optical compensation layer is set to be 10 degrees or more than the twist angle の of the driving liquid crystal layer.
By making the angle 130 degrees smaller, higher contrast can be obtained.

Further, the retardation Rc of the optical compensation layer is set in the range of 400 nm to 900 nm, the retardation Rd of the driving liquid crystal layer is set in the range of 660 nm to 960 nm, and -300 nm <Rc-Rd <0 nm is satisfied. The rotation angle θ from the orientation direction on the front side of the layer to the orientation direction on the back side of the optical compensation layer is −65 degrees to −100.
Degree, or the rotation angle の from the alignment direction on the front side of the optical compensation layer to the absorption axis direction of the polarizing layer is −30.
By setting it within the range of degrees to +25 degrees, higher contrast can be obtained.

Further, the weight can be reduced by using a twisted retardation plate in which a liquid crystal polymer is solidified.

Further, by shielding the space between the pixel electrodes with a black matrix, it is possible to improve the contrast during reflection and transmission.

Further, by making the light-transmitting substrate made of a synthetic resin, the weight can be reduced and the impact resistance can be improved.

By using a material that transmits circularly polarized light from the back as the light reflection layer, it is possible to realize a transflective liquid crystal display device capable of displaying even without external light.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a structure of a liquid crystal display device according to one embodiment of the present invention.

FIG. 2 is a view showing a definition of an axis angle of each optical element in the embodiment.

3 (1) and 3 (2) show a twist angle χ = 2
It is a graph which shows the relationship between the twist angle (phi) and contrast value Co at 20 degrees and 230 degrees, respectively.

FIGS. 4 (1) and 4 (2) show a twist angle χ = 2
It is a graph which shows the relationship between the twist angle (phi) and contrast value Co at 40 degrees and 250 degrees, respectively.

FIG. 5 is a graph showing a relationship between a twist angle φ and a contrast value Co when the twist angle χ = 260 degrees.

FIGS. 6 (1) and 6 (2) show twist angles χ and | φ | − | χ | when the reflectance is 40% or more and 46% or more.
6 is a graph showing the relationship between

7 (1) and 7 (2) show a twist angle χ = 2.
It is a graph which shows the relationship between the twist angle (phi) and retardation Rc at 20 degrees and 230 degrees, respectively.

8 (1) and 8 (2) show a twist angle χ = 2
It is a graph which shows the relationship between the twist angle (phi) at 40 degrees and 250 degrees, and the retardation Rc, respectively.

FIG. 9 is a graph showing the relationship between the twist angle φ and the retardation Rc when the twist angle χ = 260 degrees.

FIGS. 10 (1) and 10 (2) are graphs showing a relationship between the twist angle φ and the retardation Rc when the reflectance L is 40% or more and 46% or more.

FIGS. 11 (1) and 11 (2) are graphs respectively showing the relationship between the twist angle φ and the retardation Rd when the twist angles χ = 220 degrees and 230 degrees.

FIGS. 12 (1) and 12 (2) are graphs respectively showing the relationship between the twist angle φ and the retardation Rd when the twist angle χ = 240 degrees and 250 degrees.

FIG. 13 is a graph showing the relationship between the twist angle φ and the retardation Rd when the twist angle χ = 260 degrees.

14 (1) and 14 (2) are graphs showing the relationship between the twist angle φ and the retardation Rd when the reflectance L is 40% or more and 46% or more.

FIG. 15A is a graph showing a relationship between the retardation Rd and the retardation Rc when the reflectance L is equal to or greater than 40%, and FIG.
5 is a graph showing a relationship between retardation Rd and Rc-Rd when the ratio is equal to or more than%.

FIGS. 16 (1) and 16 (2) show the twist angle φ and the angle θ when the twist angles χ = 220 degrees and 230 degrees, respectively.
6 is a graph showing the relationship between

FIGS. 17 (1) and 17 (2) show the twist angle φ and the angle θ when the twist angle χ = 240 degrees and 250 degrees, respectively.
6 is a graph showing the relationship between

FIG. 18 is a graph showing the relationship between the twist angle φ and the angle θ when the twist angle χ = 260 degrees.

FIGS. 19A and 19B show the twist angle φ and the angle θ when the reflectance L is 40% or more and 46% or more.
6 is a graph showing a relationship with the graph.

FIGS. 20 (1) and 20 (2) show the twist angle φ and the angle ψ when the twist angle χ = 220 degrees and 230 degrees.
6 is a graph showing the relationship between

FIGS. 21 (1) and 21 (2) show the twist angle φ and the angle ψ when the twist angle χ = 240 degrees and 250 degrees.
6 is a graph showing the relationship between

FIG. 22 is a graph showing the relationship between the twist angle φ and the angle ψ when the twist angle χ = 260 degrees.

FIGS. 23 (1) and 23 (2) show the twist angle φ and the angle ψ when the reflectance L is 40% or more and 46% or more.
6 is a graph showing a relationship with the graph.

FIG. 24 is a diagram illustrating a display principle of a transflective liquid crystal display device according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 polarizing plate 2 twist compensation layer (optical compensation layer) 3 forward scattering plate 4 upper glass substrate 5 transparent electrode 7 alignment film 8 STN liquid crystal layer (drive liquid crystal layer) 9 overcoat layer 10 color filter 11 reflection function layer 12 lower glass Substrates 13-17 directions χ, φ Twist angle θ, ψ Angle Rc, Rd Retardation

Claims (12)

[Claims] 1. A drive liquid crystal layer for driving a display capable of changing the orientation direction of a twist-aligned liquid crystal polymer, and a drive liquid crystal having a structure in which polymers are twist-aligned in a twist direction opposite to the drive liquid crystal layer. A liquid crystal display device comprising: an optical compensation layer that transmits light from a layer, wherein a twist angle of the optical compensation layer is smaller than a twist angle of a driving liquid crystal layer. 2. A driving liquid crystal layer having a structure in which a display driving liquid crystal layer capable of changing the orientation direction of a twist-aligned liquid crystal polymer and a polymer in which a polymer is twisted in a twist direction opposite to the driving liquid crystal layer. An optical compensation layer that transmits light from the layer, a light reflection layer disposed on the back side of the driving liquid crystal layer, and a polarizing layer disposed on the front side of the optical compensation layer, and the twist angle of the optical compensation layer Is a liquid crystal display device having a smaller twist angle than a driving liquid crystal layer. 3. The twist angle of the driving liquid crystal layer is 220.
3. The liquid crystal display device according to claim 1, wherein the twist angle of the optical compensation layer is 10 to 130 degrees smaller than the twist angle of the driving liquid crystal layer. 4. The retardation of the optical compensation layer is 4
3. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is within a range of 00 nm to 900 nm. 5. The retardation of the driving liquid crystal layer is 6
The liquid crystal display device according to claim 1, wherein the thickness is in a range of 60 nm to 960 nm. 6. The retardation Rc of the optical compensation layer and the retardation Rd of the driving liquid crystal layer are less than −300 nm.
2. The lens according to claim 1, wherein Rc-Rd <0 nm is satisfied.
Or the liquid crystal display device according to 2. 7. When the twist direction of the liquid crystal polymer arranged from the back side to the front side of the driving liquid crystal layer is positive, the major axis of the liquid crystal polymer located at the back side end of the optical compensation layer is: 3. The liquid crystal display device according to claim 1, wherein the liquid crystal polymer positioned at the front end of the driving liquid crystal layer is oriented in a direction rotated by -65 degrees to -100 degrees. 8. When the twist direction of the liquid crystal polymer arranged from the rear side to the front side of the driving liquid crystal layer is positive, the absorption axis of the polarizing layer is positioned at the front end of the optical compensation layer. 3. The liquid crystal display device according to claim 2, wherein the long axis of the polymer is oriented in a direction rotated from -30 degrees to +25 degrees. 9. The liquid crystal display device according to claim 1, wherein the optical compensation layer is a twisted retardation plate obtained by solidifying a liquid crystal polymer in a twisted arrangement. 10. The liquid crystal display device according to claim 1, wherein a light-shielding black matrix is provided between pixel electrodes for driving the driving liquid crystal layer for each pixel. 11. The liquid crystal display device according to claim 1, wherein the driving liquid crystal layer is sandwiched between a pair of translucent substrates made of synthetic resin. 12. The liquid crystal display device according to claim 2, wherein the light reflection layer transmits circularly polarized light from the back.