JPH08248414A - Reflection type liquid crystal display element - Google Patents

Abstract

PURPOSE: To obtain a reflection type LCD (liquid crystal display element) having high reflectivity and contrast ratio characteristic and excellent dependency on visual angle and light source angle while maintaining the polarizability of incident light by providing the reflection surface of a reflection layer with a translucent medium layer having a specific refractive index. CONSTITUTION: This reflection type liquid crystal display element includes the translucent medium layer 20 having the refractive index of >=1.6 on the reflection surface of the reflection layer 18. Namely, the liquid crystal display cell 11 constituting the LCD has a structure formed by arranging a liquid crystal layer 16 between an observation side substrate 12 having transparent electrodes 14 and a counter substrate 13 having transparent electrodes 15, regulating the spacing therebetween with spacers 21 and sealing the spacing with a sealant 22. The liquid crystal layer 16 is nematic liquid crystals and are guest-host type liquid crystals consisting of liquid crystal molecules LM and dichromatic dyes GH. A quarter-wave plate 19 is stuck to the surface of the counter substrate 13 and the reflection layer 18 coated with the translucent medium layer 20 having the refractive index of >=1.6 on the rugged reflection surface of an approximately crown shape via an adhesive 23 is stuck onto this quarter- wave plate 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective liquid crystal display device.

[0002]

2. Description of the Related Art A liquid crystal display element (hereinafter abbreviated as LCD) is a word processor, a personal computer, a projection type T
Widely used for V, small TV, etc., but reflective LCD
Does not require a backlight for display of OA equipment and the like, and thus can reduce power consumption and is suitable for portable use. Since the reflective LCD uses the light of outside light,
When the reflectance of the LCD itself is low, it poses a practical problem.

When the reflective LCD is classified from the viewpoint of the reflectance of the LCD itself, a display mode using two polarizing plates,
It can be classified into three modes: a display mode in which one sheet is used and a display mode in which it is not used.

As a display mode using two polarizing plates,
For example, it is a TN type LCD shown in FIG. Here, the liquid crystal cell 1 comprises a liquid crystal layer 6 sandwiched between electrodes 4 and 5, two transparent substrates 2 and 3, and a pair of polarizing plates 7 is provided on both outer sides of the transparent substrate.
1 and 72 are attached, and a reflector 8 is arranged on the outer surface of one polarizing plate 72. The figure shows one pixel region p consisting of a modulation part A having an electrode and a non-modulation part B having no electrode. In this TN type LCD, the optical path L passes through the polarizing plates 71 and 72 four times in total, and passes through the substrates 2 and 3 four times in total. Of the transmittances of these portions, the transmittance of the polarizing plate is 50% or less in principle at least once, and for example, the polarizing plate functioning as a polarizer is actually 40% or more. Since other polarizing plates and substrates also have their own absorption, the reflectance is extremely low.

As a display mode using one polarizing plate,
For example, it is an ECB type LCD with a single polarizing plate mode shown in FIG. 35, and the same reference numerals as those in FIG. 34 denote the same parts. The same applies to the other figures. In comparison with the TN LCD, the polarizing plate 71 passes through the optical path twice and the substrate 2 passes through the optical path only twice. The TN
The transmittance of the polarizing plate is 50% or less in principle for at least one time as in the case of the type LCD, and is actually 40% or more. However, in terms of the optical path, it is possible to reduce the light absorption for two times of the polarizing plate and two times of the substrate, so that the reflectance is slightly higher than that of the TN type LCD.

Compared with these, the display mode not using a polarizing plate is, for example, the PC-GH type LCD shown in FIG.
The GH-HOMO LCD shown in FIG. 7 and the two-layer GH-HOMO LCD shown in FIG. Since neither of the methods uses a polarizing plate, the transmittance is at least 50% or less in principle as in the display mode using the polarizing plate, and in fact, a polarizing plate having 40% or more is not used. Only brightens. Also, the single-polarizer mode EC shown in FIG.
Like the B-type LCD, if a reflection plate is provided on the inner surface of the cell, it is possible to reduce the light absorption for two times of the substrate as in the ECB-type LCD with one polarizing plate mode. Therefore, the reflectance is significantly higher than that in the display mode using the polarizing plate.

However, in the PC-GH type LCD shown in FIG. 36, in order to obtain a dark state, the liquid crystal material of the liquid crystal layer 61 is given extremely strong chirality to form a molecular arrangement having a strong helical structure. Here, the symbol LM indicates liquid crystal molecules and GH indicates a dye. In order to bring this into a bright state, it is necessary to have this strong helical structure and to tilt the liquid crystal molecules LM vertically. Therefore, it is necessary to apply an extremely high voltage, which cannot be practically applied to a display having a large display capacity.

In addition, there is a certain degree of stability both in the state of being a molecular arrangement of a strong helical structure by giving chirality and in the state of being unfolded by applying a very high voltage, and the electro-optical characteristics. Hysteresis occurs in (reflectance or transmittance characteristics with respect to applied voltage).
For this reason, there is a problem that halftone display (gradation display) is difficult.

A GH-HOMO type LC shown in FIG.
In the case of D, the liquid crystal layer 62 absorbs only the polarized component in one direction, so the brightness in the dark state is more than half that in the bright state, and the contrast is 2: 1 or less, which is an extremely low value, which is not practical.

A two-layer type GH-HOMO shown in FIG.
Unlike the GH-HOMO type LCD shown in FIG. 37, the type LCD can absorb polarized components in two directions by using two layers of liquid crystal layers 62 and 62 having crossed orientations and high contrast can be obtained. Both the liquid crystal layers need to be driven, and a parallax corresponding to the thickness of the substrate 2a between the two liquid crystal layers occurs. Therefore, it cannot be applied to high-definition display, and the cost becomes high.

In addition, Cole and Kashnow (HSCole
RAKashnow Applied Physics Letters, Vol.30, No.12,
pp619-621 (15 June 1977)) is a GH-HOMO type LC
A reflective LCD having a configuration in which a quarter-wave plate and a diffuse reflection plate are added to D is proposed. The structure of this LCD is shown in FIG. In the reflective LCD shown in FIG. 39, as shown in FIG. 40, the incident light Li emitted from the liquid crystal layer 62 of the liquid crystal cell is transmitted through the quarter-wave plate 9 and is reflected by the diffuse reflection plate 8 as Lr. By passing through the quarter-wave plate 9 again, the phase is shifted by one-half wavelength and the function of entering the liquid crystal cell 1 again is obtained. Here, only linearly polarized light is a quarter
The phase is changed by the wave plate 9. Therefore, the same light control as that of the two-layer type GH-HOMO type LCD shown in FIG. 38 can be obtained by the one-layer liquid crystal layer 62, that is, the one-layer liquid crystal cell 1.

These reflective LCDs necessarily form a reflective layer that reflects light. Generally, the reflective layer is a reflective plate attached to the outer surface of the cell. Conventionally, as a reflector
It uses a structure in which aluminum foil is attached to a plastic film, a structure in which aluminum is vapor-deposited on plastic with irregularities on the surface, and white fine paper. It has also been proposed to provide irregularities on the substrate surface similarly to the structure in which aluminum is vapor-deposited on the inner surface of the cell, and aluminum is vapor-deposited thereon to form a reflective layer. In this case, there are a method of using the reflection layer itself as an electrode (reflection electrode) and a method of forming an electrode separately from the reflection layer (in this case, the reflection layer is a reflection film).

The above-mentioned reflector having the aluminum foil attached to the plastic film and the reflector having aluminum vapor-deposited on the plastic having the uneven surface are applied to any of the above display modes, and the substrate is formed on the inner surface of the cell. One with a single polarizing plate mode ECB type LCD or PC is one in which unevenness is provided on the surface and aluminum is vapor-deposited on it as a reflective layer.
Application to -GH type LCD, GH-HOMO type LCD, and two-layer type GH-HOMO type LCD is under study. Since these display modes do not require an optical medium (polarizing plate or retardation plate) for controlling light between the reflective layer and the liquid crystal layer, there is no need to form the optical medium on the reflective layer, that is, on the inner surface of the cell. It is possible to easily manufacture a cell.

The reflecting plate made of white fine paper is a display mode in which the light reflection in the reflecting layer is not involved in the light control for controlling the brightness of the display, that is, one polarizing plate mode E.
It has been applied to display modes other than the reflection type LCD having a configuration in which a quarter wavelength plate and a diffuse reflection plate are added to the CB type LCD or the GH-HOMO type LCD.

The reflective layer in these reflective LCDs greatly affects the "brightness" and "contrast ratio" characteristics of the display, their viewing angle dependence, and the angle dependence between the light source and the LCD.

The reflective layer used in the conventional reflective LCD has the "brightness" and "contrast ratio" of the above-mentioned display.
The characteristics and their viewing angle dependency, the angle dependency between the light source and the LCD are not sufficient, and the "brightness" and their viewing angle dependency, the reflection of the reflective layer that can determine the angle dependency between the light source and the LCD The rates, their viewing angle dependence, and the angle dependence between the light source and the LCD are low and narrow, and so were the "contrast ratios" as well. Furthermore, the display mode in which the light reflection in the reflection layer is involved in the light control for controlling the brightness of the display, that is, the ECB type LCD or the GH-HOMO type LCD with the single-polarizer mode is equipped with the quarter-wave plate and the diffuse reflection plate. When a conventional reflective layer is used in the reflective LCD with the added configuration, when the light is reflected by the reflective layer, the polarization state of the light incident on the reflective layer is significantly changed and reflected, which affects the control of display. Then, the "contrast ratio" characteristic was deteriorated.

The inventors of the present invention have proposed such a conventional reflective LCD.
As a means for solving the problem of the reflective layer used for the above, according to Japanese Patent Application No. 7-22762, the reflecting surface is arranged in a dense hexagonal array in which the convex portions of the spherical caps having a specific size and shape are arranged in a substantially dense hexagonal array to form a honeycomb structure. In Japanese Patent Application No. 7-33294, a reflective layer in which convex portions having a specific polygonal pyramid shape are planarly arranged is proposed.

"A reflective liquid crystal display device or a semi-transmissive liquid crystal display device having at least one substrate with electrodes, a liquid crystal layer controllable by the electrodes, and a reflective layer (reflective film, reflective plate, reflective electrode, etc.) for reflecting light. In the transmissive liquid crystal display element, each of these reflective layers has the "brightness" and "contrast ratio" characteristics of the display of a reflective LCD, as compared with the conventional metal reflective layer or the reflective paper having a matte surface. The viewing angle dependence and the angle dependence between the light source and the LCD are improved.

[0019]

SUMMARY OF THE INVENTION The present invention is a reflection type LC.
For the purpose of further improving the characteristics of the reflective layer used for D, and further improving the "brightness" and "contrast ratio" characteristics of the display, their viewing angle dependence, and the angle dependence between the light source and the LCD. It was made.

The present invention includes not only the reflective layer proposed by the above-mentioned inventors but also a reflective LCD having a conventional reflective layer, and the "brightness" and "contrast ratio" of the display of the reflective LCD. Characteristics and their viewing angle dependence, light source and LC
This is done for the purpose of further improving the angle dependency with respect to D.

[0021]

SUMMARY OF THE INVENTION The present invention provides at least one
In a reflective liquid crystal display device having a substrate having a sheet of transparent electrodes, a liquid crystal layer controlled by the electrodes, and a reflective layer for reflecting light transmitted through the liquid crystal layer, a reflective surface of the reflective layer has a refractive index of 1 A liquid crystal display device comprising a transparent medium layer of 6 or more.

Here, the reflection layer includes a plate-shaped substrate such as a reflection plate, a film-shaped or film-shaped substrate, and a reflection film also serving as an electrode.

Further, a reflective liquid crystal having a liquid crystal display cell including at least one substrate having a transparent electrode, a liquid crystal layer controlled by the electrode, and a reflective layer for reflecting light transmitted through the liquid crystal layer. In the display element, the liquid crystal display element is obtained in which the reflective layer is attached to the outer surface of the liquid crystal display cell with a translucent medium having a refractive index of 1.6 or more as an adhesive.

Further, a reflective liquid crystal having a liquid crystal display cell including at least one substrate having a transparent electrode and a liquid crystal layer controlled by the electrode, and a reflective layer for reflecting light passing through the liquid crystal layer. In the display element, there is provided a liquid crystal display element in which the reflective layer is formed by laminating a translucent medium layer having a refractive index of 1.6 or more on a reflective surface, and is integrated with an outer surface of the liquid crystal display cell via an adhesive. I will get it.

Further, in relation to the above, there is obtained a liquid crystal display device in which the surface of the reflective layer is a reflective surface or a rough surface in which a large number of convex shapes are arranged in a plane.

Furthermore, a liquid crystal display device is obtained in which the liquid crystal layer is made of nematic liquid crystal to which a dichroic dye is added, and a quarter wavelength plate is provided between the liquid crystal layer and the reflection layer.

Furthermore, the surface of the reflective layer is made of a metallic luster
It is desirable to form it with 1.

[0028]

The operation of the present invention will be described below with reference to the drawings.
The details will be described.

In general, a reflective LCD does not have a light source on its system and uses external light for display, so the display light source changes depending on the environment in which it is used. In most environments, the light incident on the LCD is not perfectly diffuse and is incident from various angles. Therefore, if all the incident light is specularly reflected on the reflective layer of the reflective LCD, the reflective LCD
Becomes a mirror that reflects the background, making it difficult to recognize the display.

When observed from a direction other than the regular reflection direction in which the incident light intensity is strong, almost no reflected light is obtained and only a dark display can be observed. Therefore, the reflective LC
In the reflective layer of D, it is essential that the reflective properties have a certain level of diffusivity. The reflection layer (reflection plate) that has been used in the past, in order to obtain this diffusive reflection characteristic, vapor-deposit metal with a high reflectance on a substrate with unevenness on the surface,
I used paper to obtain strong light diffusion.

However, although a conventional reflector having a highly reflective metal vapor-deposited on a substrate having irregularities on the surface can obtain light diffusivity, it is optimally designed to increase the overall reflectance. The reflectance is low. Also,
The reflecting plate using paper has a strong light absorption by the reflecting plate itself and is extremely excellent in diffusivity, but the reflectance is extremely low.

In addition, as described above, the display mode in which the light reflection in the reflective layer is involved in the light control for controlling the brightness of the display, that is, the one-polarizing plate mode ECB type LCD or GH.
-When a conventional reflective layer is used in a reflective LCD having a quarter-wave plate and a diffuse reflective plate added to the HOMO type LCD, when light is reflected by the reflective layer, it is incident on the reflective layer. The polarization state of light is remarkably changed and reflected, which affects the control of display and deteriorates the "contrast ratio" characteristic.

FIG. 7 schematically shows an example of the basic structure of the conventional reflector 8 for comparison with the present invention. Figure 7
7A is an Al vapor deposition type, and FIG. 7B is a paper type. The Al vapor deposition type has many flat parts 8a,
The reflectance is low in directions other than the regular reflection direction (C in the figure). Also, there are many regions 8b and directions in which the number of reflections by the reflective layer 8 is two or more (a and b in the figure). Although any reflection is metallic reflection, even if it is metallic reflection, it always absorbs each reflection. Even with aluminum and silver, which are said to have high metal reflectance, 5-10% per reflection
With absorption of. As a result, if the number of times of reflection on the reflecting surface 8A is two or more, the reflectivity decreases accordingly. For these reasons, a high reflectance cannot be obtained with the shape as shown in FIG. In addition, the polarization state of the light incident on the reflective layer differs between the region where the number of reflections is two or more and the region where the reflection is performed only once, and the polarization state of the reflected light cannot be controlled.

In the paper type of FIG. 7B, the diffusivity of the light 1 is higher than that of FIG. 7A due to the refraction effect and the like, but the number of reflections is greater than that of the Al vapor deposition type, and the transmitted light lt is also higher. A lot of light is absorbed. Therefore, the reflectance is extremely low, and the polarization state of the incident light is almost destroyed.

As described above, the conventional reflector does not provide sufficient reflectance and reflection while maintaining polarization.

1 to 4 show a configuration example of the present invention.

The configuration of FIG. 1 is L as shown in FIG.
A liquid crystal display cell 11 constituting a CD has a liquid crystal layer 16 disposed in a gap between an observation side substrate 12 having a transparent electrode 14 and a counter substrate 13 having a transparent electrode 15, and the gap is regulated by a gap agent 21 and sealed. It has a structure sealed with the agent 22. The liquid crystal layer 16 is a nematic liquid crystal, and includes liquid crystal molecules LM and 2
It is a guest-host type liquid crystal composed of a chromatic dye GH.

A quarter-wave plate 19 is provided on the surface of the counter substrate 13.
1B, the translucent medium layer 20 having a refractive index of 1.6 or more is attached to the surface of the quarter-wave plate 19 with an adhesive 23.
The reflective layer 18 applied to the spherical crown-shaped concave-convex reflective surface is attached. This configuration operates in the display modes of FIGS. 39 and 40.

In the configuration of FIG. 2, the liquid crystal display cell 11 and the quarter-wave plate 19 have the same configuration as that of FIG. 1, and the refractive index is 1.6.
The above-mentioned translucent medium layer 20 is thinly provided so as to follow the convex-shaped surface of the reflection surface 181 of the reflective layer 18 and have the same convex shape. The display mode operates in FIGS. 39 and 40.

In the structure shown in FIG. 3, the adhesive layer itself for bonding the reflective layer 18 to the liquid crystal display cell 11 and the quarter-wave plate 19 having the same structure as in FIG. It is formed of the optical medium 20.

In the structure shown in FIG. 4, a reflective layer 18 is provided on the inner surface of the counter substrate 13 of the liquid crystal display cell 11, that is, the surface on the liquid crystal layer side, and the reflective surface of this reflective layer has a light-transmitting property with a refractive index of 1.6 or more. The medium layer 20 is applied. Although the transparent electrode 15 is provided on the medium layer 20, the transparent medium layer 20 may also serve as the transparent electrode. In this case, it is desirable to form an ITO film as the translucent medium.

The above-mentioned reflective layer has a metal reflective film formed by roughening one surface of a substrate on which the reflective layer is formed,
The reflective layer proposed by the present inventors can be used.

That is, the latter configuration is disclosed in Japanese Patent Application No. 7-22.
No. 762 is a reflecting layer having a honeycomb structure in which spherical convex portions of a reflecting surface having a specific size and shape are arranged in a substantially dense hexagonal array in a plan view, and specifically, it is shown in FIG. 1 (b). As shown in the figure, the surface shape of the reflective layer has a bottom radius a of 30 μm.
0.087 to 0.707 times (0.087 ≦ a ≦ 0.707) of the radius r (r ≦ 30 μm) of the following sphere,
This is a structure (honeycomb structure) in which convex portions 18A having a shape of a spherical crown (a part of a true sphere) whose height t is smaller than the radius r of the sphere are arranged in a substantially dense hexagonal array in a plan view, and the convex portion 18A is formed on the surface of the reflection layer. At least the surface is made of a metal having a metallic luster so that the light reflection is metallic reflection (regular reflection).

In Japanese Patent Application No. 7-33294,
The reflecting layer is a reflecting layer in which convex shapes of a specific polygonal pyramid are arranged in a plane, and specifically, the surface shape of the reflecting layer is a three-sided pyramid, a four-sided pyramid, a six-sided pyramid, or an eight-sided pyramid. The pyramids are arranged so that their bases touch each other,
In addition, the inclination angle θ of the sides of the three-sided pyramid, the four-sided pyramid, the six-sided pyramid, the eight-sided pyramid, and the four-sided pyramid (the angle formed by the side surface and the bottom surface) is 5 ° to 25 °, and the value of the θ is the same for adjacent pyramids. Are different from each other and the arrangement pitch is 30 μm or less when viewed two-dimensionally, and at least the surface is made of a metal having metallic luster so that the light reflection on the surface of the reflection layer becomes metal reflection (regular reflection). It will be.

According to the reflection layer having such a surface shape, each convex portion contributes to diffuse reflection and also performs reflection maintaining polarization. Compared with the conventional reflection layer, these reflection layers have a high reflectance and a high polarization ratio because the light reflection in the reflection layer is only primary reflection and has a convex surface capable of reflecting in various directions and directions. Is getting a reflection that maintained.

The present invention further enhances the scattering and reflection of the reflective layer having such a structure and the conventional reflective layer having a roughened matte surface. As shown in FIGS. 1 to 4, the reflective surface has a translucent property. The medium layer is interposed.

8 to 11 and FIGS. 12 to 20,
Regarding the structure in which the translucent medium layer according to the present invention is combined with the reflective layer proposed by these inventors or the conventional reflective layer,
Furthermore, the measurement results of the "brightness" and "contrast ratio" characteristics of the display, their viewing angle dependence, and the angle dependence between the light source and the LCD when a reflective LCD is combined with a liquid crystal display cell are shown. .

The measurement was carried out by the measuring system and measuring device shown in FIG. As shown in the figure, the luminance meter 40 is fixed in the direction z normal to the surface of the sample 41, and the incident angle (ω) of the light source 42 is changed to measure the luminance. According to the measurement by such a measurement system, the same result can be obtained even in the measurement system in which the light source and the luminance meter are exchanged, so that the visual angle characteristic (depending on the viewing direction of the observer) when the light source 42 is in the normal z direction is obtained. The angle dependency between the light source and the LCD when the observer is positioned in the normal direction is measured at the same time.

In the measurement, the reflectance of the reflective layer alone, and the reflectance and contrast ratio when applied to various reflective LCDs are measured. The reflectance was evaluated by measuring the luminance in the normal direction with respect to the incident light incident from the incident angle of 30 ° (ω = 30 °) and setting the luminance of the standard white plate to 1 (100%).

8 to 11 show the measurement results of the reflectance of the reflective layer alone, FIG. 8 shows the measurement results of the reflectance r1s of the standard white plate and the reflectance r1h of the reflector made of high quality paper, and FIG. 9 shows the conventional one. The reflectance r2 of the Al vapor-deposited reflector (M type reflector manufactured by Nitto Denko Corporation) which is the reflector of FIG. 10 is the reflectance r3 of the honeycomb reflector (Japanese Patent Application No. 7-22762) itself, and FIG. A pyramidal reflector with convex pyramids arranged (Japanese Patent Application No. 7-
No. 33294) itself is the measurement result of the reflectance r4.

Further, FIG. 12 shows a TN-LC reflecting plate made of high-quality paper whose measurement result r1h for the reflecting layer alone is shown in FIG.
Reflectivity r1h / TN when bonded to D with an adhesive (polarizing plate made by Nitto Denko Corporation, adhesive for reflector, refractive index 1.43, same adhesive used for the following measurements) And the contrast ratio c1h / TN.

FIG. 13 shows the result of measurement of the reflectance r2 of the reflective layer alone in FIG. 9 (see FIG. 9).
2 is a measurement result of reflectance r2 / TN and contrast ratio c2 / TN when a reflector consisting of a (type reflector) is attached to a TN-LCD with an adhesive.

FIG. 14 shows the reflectance r of the reflection layer alone in FIG.
3 shows the measurement results of the reflectance r3 / TN and the contrast ratio c3 / TN when the reflection plate composed of the honeycomb reflection plate showing the measurement result of 3 was attached to the TN-LCD with an adhesive.

FIG. 15 shows the reflectance r of the reflection layer alone in FIG.
TN is a reflector consisting of a pyramidal reflector showing the measurement results of 4
-Reflectance r when bonded to LCD with adhesive
It is a measurement result of 4 / TN and contrast ratio c4 / TN.

FIG. 16 shows the reflection when a reflection plate made of high-quality paper showing the measurement result of the reflectance r1h of the reflection layer alone is attached to the LCD of the display mode shown in FIGS. 39 and 40 with an adhesive. It is the measurement result of the rate r1h / GH and the contrast ratio c1h / GH.

FIG. 17 shows the reflectance r2 of the reflection layer alone in FIG.
In the case where a reflection plate composed of an Al vapor-deposited reflection plate (M type reflection plate manufactured by Nitto Denko Corporation) showing the measurement results is attached to the LCD of the display mode shown in FIGS. 39 and 40 with an adhesive. It is a measurement result of reflectance r2 / GH and contrast ratio c2 / GH.

FIG. 18 shows a reflection plate made of a honeycomb reflection plate whose measurement results are shown in FIG. 10 for the reflection layer alone.
It is a measurement result of the reflectance r3 / GH and the contrast ratio c3 / GH when it is pasted with an adhesive on the LCD of the display mode shown in FIG.

FIG. 19 shows the reflection when a reflector consisting of a pyramidal reflector whose measurement results for the reflective layer alone are shown in FIG. 11 is attached to the LCD of the display mode shown in FIGS. 39 and 40 with an adhesive. It is a measurement result of the rate r4 / GH and the contrast ratio c4 / GH.

FIG. 20 shows the result of measurement of the reflectance r2 of the reflective layer alone in FIG. 9 (see FIG. 9).
Reflector r2 / GH when a reflector consisting of a (type reflector) is combined with the LCD of the display mode shown in FIGS. 39 and 40.
/ O and the contrast ratio c2 / GH / O are the measurement results, and in this case, there is space (air) on the reflective layer without bonding with an adhesive or the like.

As is clear from the results of FIGS. 8 to 11 and FIGS. 12 to 20, the reflectance of the reflector alone, the reflectance of the LCD, and the contrast ratio have the best characteristics in the normal direction (ω = 0 °). , The characteristics become worse as the angle (ω) becomes larger. From FIGS. 8 to 11, the viewing angle of the reflectance of the reflector alone,
Looking at the angle dependence, the Al-deposited reflector shown in FIG. 9 has the best front reflectance, but the viewing angle and angle dependence are extremely poor, and even if the observation direction is slightly changed or the position of the light source is slightly changed. There is a problem in practical use because the appearance is remarkably deteriorated.

In comparison with this, other three examples (FIGS. 8 and 1)
0, FIG. 11) is relatively excellent in viewing angle and angle dependency.
In particular, the reflective layer shown in FIGS. 10 and 11 is superior in absolute value of reflectance itself to the reflective layer of FIG. 8, and therefore exhibits sufficiently excellent characteristics even when the viewing angle and the position of the light source are changed. However,
Compared to the front, at ω = 45 ° about half, ω = 60
It is as low as a quarter at °. Therefore, when the viewing angle or the environment changes, the appearance changes.

12 to 20, the absolute value of the reflectance is lower than that in FIGS. 8 to 11. This is because the liquid crystal display cell is added on the reflective layer.

Comparing FIG. 12 to FIG. 15 and FIG. 16 to FIG. 17, both reflectances have the same relative relationship as the result of FIG. 8 to FIG. 12 to 15 and FIG.
6 and 17 are compared, FIGS. 16 and 17 are superior in reflectance and angle dependency. This is due to the characteristics of the display mode. Looking at the contrast characteristics, the reflection plate made of high-quality paper in both two display modes has a remarkably low contrast ratio. This is because the polarization state is not maintained and is due to the characteristics of the reflector.

Similarly to the reflectance, FIG. 14, FIG. 15 and FIG.
8 and the configuration shown in FIG. 19 are superior in viewing angle and angle dependency as compared with others. However, like the reflectance, it is clear that there is a viewing angle and angle dependency as compared with the front characteristic, and the appearance changes when the viewing angle and the environment change.

Further, FIGS. 17 and 20 are the same for the reflective layer and the LCD, and are different only in the refractive index on the reflective layer. That is, in the configuration of FIG. 17, the refractive index of the layer on the reflective layer is 1.43 of the adhesive, and in the configuration of FIG. 20, the refractive index of the layer of the reflective layer is 1.00 of the air. Comparing the two, the configuration of FIG. 17 has a gentler viewing angle and angle dependency. Since the same reflecting layer (reflecting plate) is used, the total amount of reflected light is considered to be almost the same. Therefore, the difference between the two is the difference between concentrated reflection in one direction or dispersion in various directions and reflection.

The viewing angle characteristics may not need to be wide depending on the application, but the angle dependence (angle between the light source and the LCD normal azimuth) becomes a problem because the usable environment is limited. Particularly, in the case of excellent characteristics only near ω = 0 °, since the observer exists in that direction, the light source is blocked, and there is no environment for practical use.

As described above, the reflective LCD and the reflective layer have a viewing angle and an angle dependency, and if they are improved, the display performance will be improved. In some cases, it may be a problem in practical use, so that it also has practicality.

LCD of the present invention as shown in FIGS.
Is provided with a reflective layer 18 and the reflective surface 181 of the reflective layer
Immediately above the layer 20 made of a transparent medium having a refractive index of 1.6 or more.
It is characterized by having. In FIG. 6, L provided with a layer 20 made of a transparent medium having a refractive index of 1.6 or more
The function of light reflection of CD is shown. As shown in FIG. 6 (a), the incident light l1 has a refractive index of 1.6 or more.
When passing through the liquid crystal cell 11, the refractive index (n20, n20,
n20 ≧ 1.6) and the refractive index of air 30 (n30, n30 = 1.
The traveling direction is determined by the ratio of 0). Here, as shown in the figure, even if the incident lights li, li ... Are parallel, the reflection layer 18 diffusely reflects the reflected light lr.
Are reflected in various directions.

As described above, since the reflective layer of the reflective LCD emits the reflected light in a direction different from the regular reflection direction of the traveling direction of the incident light, the light lr emitted from the reflective layer is in the environment (the environment of the light source). It is assumed that the light is emitted in various directions without depending on it. In particular, since diffuse reflection is remarkable in the honeycomb reflection layer and the reflection layer having a polygonal pyramid reflection surface proposed by the present inventors, the emitted light hardly depends on the angle or parallelism of the incident light.

Therefore, in consideration of the angle of the light emitted from the reflective layer of the present invention, when the light emitted from the reflective layer in various directions (angles) is emitted from the LCD as shown in FIG. Consider the angular distribution of. FIG. 6B shows that the emitted light in various directions (angles) emitted from the reflective layer is the LCD.
2 shows the angular distribution when light is emitted for two types of refractive index of the transparent medium layer 20 having a high refractive index and a low refractive index. As shown in the figure, the above-mentioned angular distribution is determined by the refractive index directly above the reflective layer and the refractive index directly above the LCD. There is air 30 just above the LCD and its refractive index is 1.0.
Therefore, if the angle of the light emitted from the LCD is θ30 and the angle of the light emitted from the reflective layer is θ20, then θ30 = sin ⁻¹ (n20 × sin θ20). Therefore, as shown in the figure, the larger n20 is, the larger θ30 is than θ20. That is, the viewing angle and angle dependency of the LCD reflectance described above are improved.

In the present invention, the value of θ20 is 1.6 or more. This is because the refractive index just above the reflection surface of the conventional reflection layer is 1.5.
This is because such a refractive index does not have sufficient viewing angle and angle dependence of the LCD reflectance as shown in FIGS. 8 to 20. By providing a layer made of a translucent medium having a refractive index of 1.6 or more, it is possible to achieve better characteristics than ever before.

Further, as shown in FIG. 6 (a), the light incident on the reflecting layer also enters at an angle close to the direction normal to the reflecting surface,
When applied to the reflective layer of the previous invention, secondary reflection at the reflective layer is reduced, which leads to an improvement in reflectance.

Further, depending on the difference in the structure of the light transmitting medium layer shown in FIGS. 1, 3 and 4, the above-mentioned effect on the angle dependence of the reflected light is hardly changed. This is because the shape of the translucent medium directly above the reflective layer is functionally similar.

However, in the configuration of FIG. 2, the shape is different. The translucent medium directly above the reflective layer follows the convex shape of the reflective layer. The protrusion is not parallel to the LCD plane,
Moreover, since it is a convex surface, the emitted light is further away from the normal direction than in the configurations of FIGS. 1, 3, and 4. Therefore, the diffusion effect is further enhanced. As described above, the angle dependence of the emitted light of the LCD of the present invention largely depends on n27. Depending on the reflective layer, the angular distribution of the emitted light is sufficient without the configuration of FIG. However, depending on the reflection layer and the reflection plate, particularly when the angle distribution of the reflected light of the reflection layer itself is narrow, the angle distribution of the emitted light becomes sufficient by adopting the configuration of FIG.

When the reflection layer is used as a reflection plate externally attached to the liquid crystal display cell 11, if the transparent medium of the present invention is used as an adhesive as shown in FIG. 3, a high refractive index transparent medium can be obtained. Since it is also used, the member can be omitted.

Further, when the refractive index of the transparent medium of the present invention is made extremely high in order to make the above-mentioned angular distribution sufficient, it may be considered that the function of the adhesive cannot be obtained in some cases. In this case, a separate adhesive may be used.

Further, the LCD of the present invention is more suitable for all reflective LCDs because at least the reflectance and the viewing angle dependence of various characteristics are improved as compared with the conventional reflective LCD. When applied to the display mode using the liquid crystal material to which the functional dye GH is added (the display modes shown in FIGS. 36, 37, 38 and 39 described above), an extremely large effect can be obtained. This is because in a display mode using a liquid crystal material to which a dichroic dye is added, incident light is hardly absorbed in the liquid crystal cell (other than the reflective layer), and the light absorption has almost no visual angle dependence. This is because the action and effect of the reflective layer of the invention can be sufficiently obtained.

Particularly, in the display mode shown in FIG. 39, it is necessary to reflect the polarized light while maintaining the polarized light in the reflective layer, and the structure of the present invention which allows the light to easily enter in the direction perpendicular to the reflective layer is extremely effective. . That is, when the reflective layer of the present invention is applied to the display mode using the liquid crystal material to which the dichroic dye is added, particularly the GH display mode shown in FIGS. 39 and 40,
Therefore, more excellent characteristic improvement can be obtained.

If the material used for the reflecting surface (surface) of the reflecting layer of the present invention has a high reflectance for visible light, the above-mentioned effects can be obtained. Among them, aluminum and silver are particularly excellent because they have high metal reflectance. However, since silver is highly corrosive, its handling is not easy. In addition, the reflectance alone has wavelength dependency, and some coloring occurs.
Therefore, aluminum and its alloys, which are inexpensive and have excellent corrosion resistance, are particularly excellent. The reflective layer of the present invention is a metal having a metallic luster on the reflective surface and has a film thickness capable of obtaining sufficient reflectance,
The base may be anything. Therefore, for example, when it is advantageous to integrally form it, such as when it is manufactured by a mold, the entire material may be formed of the material used for the reflecting surface, and when the LCD is made flexible, it is flexible. Only the surface of the film may have a metallic luster.

FIG. 5 shows a modification of the reflective layer for a reflective LCD according to the present invention. FIG. 5 (a) shows a surface on which a large number of convex portions are arranged on one surface of the transparent film substrate 18a, that is, the lower surface. 18a1 and has a refractive index of 1.6 on the same surface.
The above-mentioned translucent medium layer 20a and the metal reflection layer 18b are adhered to form the reflection layer 18. The incident light li is the substrate 1
8a is incident from the other surface, that is, the upper surface, and the metal reflection layer 1
It is reflected and scattered at 8b.

The film substrate 18a may be formed of a translucent medium having a refractive index of 1.6 or more. In this case,
A manufacturing process for forming another transparent medium can be omitted.

In the structure shown in FIG. 5B, one surface of the metal film 18c such as aluminum Al, that is, the upper surface 18c1 is roughened by etching or the like as shown in FIG. 7A, and the refractive index is 1.6. The above-mentioned translucent medium layer 20c is formed. The reflective layer 18c itself can also serve as a metal reflective layer, and the reflective layer can be formed easily and inexpensively.

In any of the configurations shown in FIG. 5, light scattering reflection can be enhanced while maintaining the optical rotatory power of the incident light, similarly to the configurations described in FIGS.

The configurations of FIGS. 1 to 4 are similar to those of FIGS.
It is needless to say that the present invention can be applied to an LCD having a configuration of a mode using a polarizing plate although it is the GH mode described in No. 0 and no polarizing plate is used.

[0085]

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 0.7 mm thick and 120 mm ×
Viscosity for liquid crystal alignment film is 60c on 90mm glass substrate
Ps polyamic acid (HL-1100, manufactured by Hitachi Chemical Co., Ltd.) was spin-coated at a thickness of 600 A (angstrom), dried at room temperature for about 5 minutes, and then spherical fine particles were formed on the polyamic acid film. As a sample, Sekisui Fine Chemical Co., Ltd. micropar (particle size 7.0 μm) was sprinkled, and thereafter, a 0.7 mm-thick substrate of 150 mm × 150 mm was placed on the substrate and slid in the substrate longitudinal direction while lightly pushing. After that, the substrate placed on the substrate was removed, and baking was performed at 150 ° C. for 2 hours to cure the polyamic acid, thereby fixing the fine spherical particles on the substrate. Here, when the dispersed state of the spherical particles is examined visually and by microscopic observation,
The fine particles were a single layer and arranged in a honeycomb structure as shown in FIG.

Then, polyamic acid (HL-1100, manufactured by Hitachi Chemical Co., Ltd.) having a viscosity of 120 cps was spin-coated at a thickness of 1 μm and baked at 150 ° C. for 2 hours.
The polyamic acid was cured. Subsequently, 5000 A of aluminum was vapor-deposited at room temperature to obtain a reflective layer used in this example. The plate-like reflective layer obtained in this example has spherical crown-shaped convex portions on the surface, the reflecting surface is made of Al having metallic luster, and the spherical crown is arranged in a planar honeycomb structure and the radius of the spherical crown is 3.5
μm, and the radius of the bottom surface of the spherical cap is about 4.9 μm. In addition, the area other than the convex portion of the spherical cap was a substantially flat concave shape.

The reflectance of the reflective surface of this reflective layer was measured by the method using the standard white plate described above in the measuring system of FIG. The results are shown in Fig. 21. The reflected light was almost achromatic.

FIG. 30 shows a liquid crystal display element 10 of the present embodiment, in which the viewing side substrate 12 and its counter substrate 13 have electrodes 14 and 15 respectively on their facing surfaces.
A liquid crystal cell 11 in which a liquid crystal layer 16 is sandwiched between the spaces 2 and 13.
And the quarter-wave plate 19 attached to the outer surface of the counter substrate 13.
Further, it has a structure in which the reflection layer (reflection plate) 18 having the above-mentioned configuration is further attached to the surface of the quarter-wave plate 19.

Both the substrates 12 and 13 are glass substrates having a thickness of 0.7 mm, and the one substrate, that is, the counter substrate 13 is shown in FIG.
It is a substrate with the MIM element 20 as shown in 0 (b) and (c). FIG. 30B shows the shape of the electrode 15 of one pixel, and FIG. 30C shows the shape of the effective display area 131. The number of pixels is 480 horizontal × 320 vertical, each pixel p has a MIM element 25 as a switching element w, and one pixel electrode size is 180 μm × 180 μm.

As the observation side substrate 12, FIG.
ITO stripe pattern electrode 1 shown in (d) and (e)
A substrate on which No. 4 was formed was prepared. Here, FIG. 30D shows a pattern shape corresponding to one pixel, and FIG.
The shape of the effective display area 121 is shown. FIG. 30 (d)
The stripe pattern width of the substrate on which the ITO stripe pattern electrode 14 shown in is formed is 180 μm (line width 17
5 μm).

The alignment film 2 is formed on the two substrates 12 and 13.
6, 27 as a polyimide aligning agent (trade name AL-105
1, manufactured by Japan Synthetic Rubber Co., Ltd. is printed in an effective display area, baked, and rubbed in a direction parallel to the ITO stripe pattern and 180 ° opposite between the opposing substrates. Thereafter, a substrate gap material 21 (trade name: Micropearl, manufactured by Sekisui Fine Chemical Co., Ltd.) having a particle size of 8 μm was sprayed on the observation-side substrate 12 at a spraying density of 100 / mm ² .
A peripheral seal pattern having an opening with a width of 5 mm was formed around the effective display area of the counter substrate by a screen printing method. The sealing material used here is a one-pack type epoxy resin (trade name: XN-21, manufactured by Mitsui Toatsu Chemicals, Inc.).

Thereafter, the two substrates 12 and 13 are superposed so that the electrode surfaces face each other, and pressure is applied so that the substrate gap becomes equal to the particle size of the substrate gap material 23, and the substrate gap is equal to the particle size of the substrate gap material 23 at 180 ° C. for 2 hours. The liquid crystal display element 10 of the present embodiment is fired.
An empty cell to be used for was obtained. Then, a nematic liquid crystal material (trade name ZLI-4801-100, manufactured by Merck Japan Ltd., Δn = 0.1055, Δε = + 4.9) showing a positive dielectric anisotropy as a liquid crystal material in the empty cell is obtained. 2.0 wt% of a black dye (trade name LA103 / 4, manufactured by Mitsubishi Kasei Co., Ltd.) was added by a reduced pressure injection method to form a liquid crystal layer 16, and the opening of the peripheral seal pattern was an ultraviolet curable resin. A liquid crystal cell 11 used in the LCD of this example was obtained by sealing with (trade name: UV-1000, manufactured by Sony Chemical Co., Ltd.).

A quarter-wave plate 19 and the above-mentioned reflection plate 18 were attached to this cell to obtain a device (LCD) 10.

Then, Ge is formed on the reflection layer 18 thus prepared.
O2 was deposited to a thickness of 2 .mu.m by sputtering. The Ge
The O2 film 20b flattens the shape of the projections on the surface of the reflective layer 18 as in the translucent medium 20 shown in FIG. The refractive index of this layer was measured and found to be 3.2. After that, as shown in FIG. 1, a quarter-wave plate 19 was attached and the reflection layer 18 was attached. The adhesive used here for bonding is polyvinyl alcohol.

The LCD thus obtained is based on the observation side substrate 1.
The light incident from 2 passes through the liquid crystal cell 11 and is reflected by the reflection layer 18
The light is reflected by the liquid crystal cell 11 and is again transmitted through the liquid crystal cell 11 and emitted from the observation side substrate, but is optically switched by the liquid crystal layer 16 controlled by the electrodes 14 and 15. The light reflected by the reflective layer 18 and transmitted through the liquid crystal cell 11 was measured, and the reflectance and contrast ratio of the LCD were measured by the measuring device shown in FIG. The measurement is carried out by arranging the luminance meter 40 at a distance of 30 cm from the center of the arrangement position of the sample 41 at a distance of 30 cm, and at the same height in the direction forming an angle of ω with the normal direction, as shown in FIG.
A high color rendering fluorescent lamp 42 that emits light at a wavelength is arranged so that the illuminance of the sample 41 portion is 580 lux, and the brightness of a standard diffuser plate (MgO plate) is measured. The reflectance r10 and the contrast ratio c10 of the sample were measured as shown in FIG.

MI so that the applied voltage to the liquid crystal layer becomes 4V.
When the reflectance was measured by applying a voltage to the entire surface (all pixels) using the M element, the reflectance at ω = 30 ° was a very high value of 68% and the reflectance at ω = 60 °. Also 50%
It was found to be extremely high, less dependent on angle, and less affected by viewing angle and light source environment than before. Moreover, when a contrast ratio was measured by applying a voltage to the entire surface (all pixels) using an MIM element so that the applied voltage to the liquid crystal layer was 0 V and 4 V, the angle dependence was small like the reflectance, and the viewing angle and the light source were small. It was found that it was less affected by the environment of than before.

(Comparative Example 1) In Example 1, an LCD was experimentally manufactured by directly using the same adhesive without providing GeO2 on the reflective layer produced.

The reflectance and the contrast ratio were measured in the same manner as in Example 1. The results are shown in Fig. 23. It was found that the angle dependence was large as compared with the result of Example 1 (FIG. 22).

(Example 2) Ceramic particles having a particle size of 0.03 µm or less were dissolved in water, coated on the reflector prepared in Example 1, dried at room temperature for 12 hours, and then 1
Firing was performed at 100 ° C. for 2 hours to prepare a prototype of the reflector plate manufactured in Example 1.

Using this mold, in polycarbonate,
O. A 3 mm thick substrate was prepared. Then, 3000 A of aluminum was vapor-deposited at room temperature on the surface having the convex portion, and then 2000 A of ITO was vapor-deposited thereon to form a substrate with a reflective electrode having a transparent medium of the present invention which also serves as a common electrode. Obtained.

Thereafter, a substrate with a TFT25A element shown in FIG. 31 was prepared as an observation side substrate.

First, as shown in FIG. 31A, the glass substrate 1
2, a gate wiring 28, a signal wiring 29, and a TFT element 25A are formed on the substrate 2, and then ITO is applied to the entire surface of the substrate by 2000.
A film having a film thickness of A was formed and patterned by a photolithography method so as to have a shape shown in FIG.

Using the two substrates thus obtained, an alignment film JAL showing a vertical alignment property as an alignment film on these substrates.
S-214-R14 (trade name, manufactured by Nippon Synthetic Rubber Co., Ltd.)
Was applied at a film thickness of 600 A and baked at 180 ° C. for 1 hour. Thereafter, the steps of spreading the substrate interstitial material to sealing baking were performed in the same manner as in Example 1, except that the alignment treatment was not performed. To produce an empty cell.

Thereafter, 8 wt% of S-811 (trade name, manufactured by Merck Japan Co., Ltd.) was added as a chiral material to the liquid crystal material used in Example 1 to obtain a spiral pitch of 1.2 μm.
In the gap between the substrates of the empty cell, liquid crystal molecules and dye molecules are arranged in a spiral shape, and at the center of the liquid crystal layer other than the alignment film surface, the spiral axis is tilted in the cell plane direction. Then, injection was performed in the same manner as in Example 1, and the injection port was sealed in the same manner as in Example 1 to obtain the LCD of this example. This embodiment is a PC-GH type display mode shown in FIG.

As in Example 1, the reflectance r20 and the contrast ratio c20 of the LCD of this Example were measured by the measuring device shown in FIG. The results are shown in Fig. 24. The entire surface (all pixels) using TFTM elements so that the applied voltage to the liquid crystal layer becomes 15V.
When a reflectance was measured by applying a voltage to ω = 30 °, the reflectance was as high as 70% at ω = 30 °.
At = 60 °, the reflectance was 53%, which was found to be extremely angle-independent as in Example 1.

(Comparative Example 2) An LCD was produced in the same manner as in Example 2, except that ITO on the reflective layer was not formed in Example 2 and only the Al film of the reflective layer was used as the reflective electrode. . The LC thus obtained in the same manner as in Example 2.
The reflectance and contrast ratio of D were measured by the measuring device shown in FIG. The results are shown in Fig. 29. When the voltage was applied to the entire surface (all pixels) using the TFTM element so that the applied voltage to the liquid crystal layer was 15 V, the reflectance was measured, and ω = 3
At 0 °, the reflectance was 68%, which was a value slightly lower than that of Example 2. However, at ω = 60 °, the reflectance was 20%, which was significantly inferior to that of Example 2.

(Embodiment 3) As shown in FIG. 32, a glass substrate having a thickness of 0.7 mm is used for the observation side substrate 12 and the counter substrate 13, and one of the substrates 12 has a line width of 175 μm, a space of 5 μm and a number of lines of 480. Was formed on the other substrate 13, and an ITO stripe electrode having a line width of 175 μm, a space of 5 μm and a number of lines of 320 was formed on the other substrate 13. The effective display area of this embodiment is the same as that of the first embodiment.

As an alignment film on each of the substrates 12 and 13, a polyimide aligning agent (trade name, AL-1051, manufactured by Nippon Synthetic Rubber Co., Ltd.) was printed on the effective display area and baked to form the substrate 12.
12a in the direction of the alignment film of 1 and arrow 1 in the direction of the alignment film of substrate 13.
Rubbing each in the direction of 3a, and then observing the substrate 12 with micro pearls (trade name: Sekisui Fine Chemical Co., Ltd.) having a particle size of 8 μm as the substrate interstitial material 21 at a spraying density of 1
00 / sprayed at mm ^2, and the peripheral seal pattern having an opening portion of the effective display area near the 5mm width of the counter substrate 13 is formed by screen printing. The seal material used here is a one-component epoxy resin XN-21 (trade name, manufactured by Mitsui Toatsu Chemicals, Inc.).

Then, the two substrates are superposed so that the electrode surfaces face each other, and baked at 180 ° C. for 2 hours while applying pressure so that the substrate gap becomes equal to the particle size of the substrate gap material. An empty cell used for the liquid crystal display element of the example was obtained. Thereafter, a nematic liquid crystal material ZLI-4801-1 showing a positive dielectric anisotropy as a liquid crystal material in the empty cell.
00 (trade name, manufactured by Merck Japan Co., Ltd. Δn = 0.1
055. Δε = + 4.9) is injected by a reduced pressure injection method to form the liquid crystal layer 16, and the opening of the peripheral seal pattern is sealed with an ultraviolet curable resin UV-1000 (trade name, manufactured by Sony Chemical Co., Ltd.), A liquid crystal cell used for the LCD of this example was obtained.

Then, a retardation plate (Polycarbonate Co., Ltd., Nitto Denko) having a retardation value of 844 nm was attached to the outer surface of the counter substrate of the observation side substrate with the optical axis aligned in the direction shown in FIG. 32 (a). It was A polarizing plate was attached to the outer surface of the observation-side substrate with the absorption axis aligned in the direction shown in FIG.

Subsequently, as shown in FIG. 32B, the reflective layer 18 manufactured in Example 1 was laminated. Here, for pasting, the high refractive index transparent highly viscous liquid R having a refractive index of 1.9 is used.
TZ-206 (trade name, manufactured by Catalysts & Chemicals Industry Co., Ltd.) is used as an adhesive to serve also as the light-transmitting medium layer 20d having a high refractive index.

The reflectance r30 and the contrast ratio c30 of the LCD of this embodiment thus obtained are shown in FIG.
It measured with the measuring device shown in 1. The results are shown in Fig. 25. The LCD of this embodiment is in the ECB type LCD mode shown in FIG. 35, and controls retardation of the liquid crystal layer (about 844 nm when no voltage is applied) by an electric field. The liquid crystal layer has a homogeneous alignment, and when an electric field is applied, the liquid crystal molecules are aligned vertically, and retardation is reduced. In this embodiment, since the initial retardation value is set to be large, the retardation can be remarkably changed with a slight change in voltage.
Option value changes. Therefore, the electro-optical characteristics are steep, and multiplex driving is possible. In this example, the driving was performed by 1/320 duty driving (effective voltage was about 2.5V). When the entire surface (all pixels) was displayed in white by this driving method and the reflectance was measured, ω = 30
The reflectance at ° is a very high value of 46%, and ω
The reflectance at = 60 ° was 36%, which was an extremely high value, and it was found that the angle dependence was small as in Example 1. In addition, the entire surface (all pixels) is displayed in black and the reflectance is measured.
When the contrast ratio at 30 ° was measured, it was 22:
It was a very high value of 1.

(Example 4) A reflective plate of this example was produced under the same conditions, manufacturing methods and materials as in Example 1, except that silver was used as the metal used for the reflecting surface of the reflective plate in Example 1. Further, the liquid crystal cell prototyped in Example 1 was laminated with the reflector of this example in the same manner as in Example 1 to form the LC of this example.
I got D.

Similar to Example 1, the reflectance of the thus obtained reflector of this example was measured by the measuring system of FIG. 41 by the method using the standard white plate as a reference. The reflected light was colored a little yellow, but the reflectance was 5 to 10% higher than the measurement result of Example 1 (FIG. 21) regardless of ω, which was an extremely high value as in Example 1.

Further, as in Example 1, the reflectance r40 and the contrast ratio c40 of the LCD of this example thus obtained were measured by the measuring device shown in FIG. Results are shown in FIG. Similar to the reflective layer of this example, the reflectance was several% higher than the result of Example 1.

(Fifth Embodiment) In the first embodiment, GeO is used as the translucent medium layer 20b provided directly on the prototyped reflector.
Instead of 2, ITO is sputtered to a film thickness of 1000.
The film was formed at A. The ITO film was a film 20 following the convex shape of the reflective layer as in the translucent medium shown in FIG.
It is considered that this is because the film thickness was made smaller than in Example 1. The refractive index of this layer was measured to be 1.9.
Met. The LCD of this example was obtained under the same conditions, manufacturing methods and materials as in Example 1.

The reflectance r50 and the contrast ratio c50 of the LCD thus obtained were measured by the measuring device shown in FIG. 41 as in Example 1. The results are shown in Fig. 27. It was found that both the reflectance and the contrast ratio had excellent characteristics as in Example 1.

Example 6 Two 0.7 mm-thick glass substrates were used, and a substrate with the MIM element 25 as shown in FIGS. 33 (a) and 33 (b) was prepared on one substrate. FIG. 33 (a)
33 is a plan view showing the shape of the electrode 15 of one pixel, and FIG.
(B) is a plan view showing the shape of the effective display area 131. The number of pixels is 480 (× 3) × 320. This substrate is used as a counter substrate of the observation side substrate. Then, as the observation-side substrate 12, the color shown in FIGS.
A substrate with filter-27 was prepared. FIG. 33 (c),
Yellow-27Y, magenta 27M, as shown in FIG.
A substrate with a color filter consisting of three colors of cyan 27C was used. The electrodes 14 forming the effective display area 121 are stripe-shaped. As in Example 1, two substrates were printed with AL-1051 (trade name, manufactured by Nippon Synthetic Rubber Co., Ltd.) as an alignment film in the effective display areas 121 and 131, and baked.
Rubbing is performed in a direction parallel to the ITO stripe pattern and opposite to each other by 180 ° between opposing substrates, and then the observation side substrate has a grain size of 8 μm as a substrate gap material.
A peripheral seal pattern in which 5 m wide micro-pallets (trade name, manufactured by Sekisui Fine Chemical Co., Ltd.) were sprayed at a spraying density of 100 / mm ^{2 and} an opening of 5 mm width was provided around the effective display area of the counter substrate. Was formed by a screen printing method. The seal material used here is XN-2 which is a one-pack type epoxy resin.
1 (trade name, manufactured by Mitsui Toatsu Chemicals, Inc.).

Then, the two substrates are superposed so that the electrode surfaces face each other, and baked at 180 ° C. for 2 hours while pressurizing so that the substrate gap becomes equal to the particle size of the substrate gap material. An empty cell used for the liquid crystal display cell of the example was obtained. Thereafter, a nematic liquid crystal material ZLI-4801-1 showing a positive dielectric anisotropy as a liquid crystal material in the empty cell.
00 (trade name, manufactured by Merck Japan Co., Ltd. Δn = 0.1
055. Δε = + 4.9) black dye LA103 / 4
2.0% by weight (trade name, manufactured by Mitsubishi Kasei Co., Ltd.) was added by a reduced pressure injection method, and the opening of the peripheral seal pattern was UV-curable resin UV-1000 (SONI Corporation). -Chemical) to obtain a liquid crystal cell used in the LCD of this example. Then, in the same manner as in Example 1, a transparent medium layer similar to that in Example 1 was provided on the surface of the reflective plate of this example, which was experimentally produced in Example 1, and laminated on the cell.

Similar to Example 1, the reflectance r60 and the contrast ratio c60 of the LCD of this example were measured by the measuring device shown in FIG. The results are shown in Fig. 28. A voltage was applied to the entire surface (all pixels) using an MIM element so that the applied voltage to the liquid crystal layer was 4 V, and the reflectance was measured at ω = 30 °. However, when the contrast ratio was measured by applying a voltage to the entire surface (all pixels) using an MIM element so that the applied voltage to the liquid crystal layer was 0 V and 4 V. , 9: 1, which was an extremely high value.

Further, as in Example 1, it was found that the angle dependence was excellent, and it was confirmed that the effects and actions of the present invention can be similarly obtained for the color-displayed LCD.

[0123]

According to the present invention, while maintaining the polarization of incident light, the reflectance and the contrast ratio characteristics are high, and the viewing angle,
A reflective LCD that is excellent in light source angle dependency is realized, and an extremely excellent reflective LCD that is not affected by the usage environment or observation method can be obtained.

[Brief description of drawings]

1A is a cross-sectional view illustrating an example of the structure of an LCD of the present invention, and FIG. 1B is an enlarged cross-sectional view showing a reflective layer.

FIG. 2 is a sectional view illustrating another example of the structure of the LCD of the present invention.

FIG. 3 is a sectional view illustrating another example of the structure of the LCD of the present invention.

FIG. 4 is a sectional view illustrating another example of the structure of the LCD of the present invention.

5 (a) and 5 (b) are cross-sectional views illustrating a modified example of a reflective layer used in the LCD of the present invention.

6A and 6B are views for explaining the action of a reflective layer used in the reflective LCD of the present invention.

7 (a) and 7 (b) are enlarged cross-sectional views for explaining the structure of a conventional reflector and the reflection characteristics and functions.

FIG. 8 is a curve diagram showing the measurement results of the viewing angle and light source angle (ω) dependence of the reflectance of the reflective layer.

FIG. 9 is a curve diagram showing the measurement results of the viewing angle and light source angle (ω) dependence of the reflectance of the reflective layer.

FIG. 10 is a curve diagram showing the measurement results of the viewing angle and light source angle (ω) dependence of the reflectance of the reflective layer.

FIG. 11 is a curve diagram showing the measurement results of the viewing angle and light source angle (ω) dependence of the reflectance of the reflective layer.

FIG. 12 is a curve diagram showing measurement results of reflectance of a reflective LCD, viewing angle of contrast ratio, and light source angle (ω).

FIG. 13 is a curve diagram showing measurement results of reflectance of a reflective LCD, viewing angle of contrast ratio, and light source angle (ω).

FIG. 14 is a curve diagram showing the measurement results of the reflectance of a reflective LCD, the viewing angle of the contrast ratio, and the light source angle (ω).

FIG. 15 is a curve diagram showing measurement results of reflectance of a reflective LCD, viewing angle of contrast ratio, and light source angle (ω).

FIG. 16 is a curve diagram showing the measurement results of the reflectance of the reflective LCD, the viewing angle of the contrast ratio, and the light source angle (ω).

FIG. 17 is a curve diagram showing the measurement results of the reflectance of the reflective LCD, the viewing angle of the contrast ratio, and the light source angle (ω).

FIG. 18 is a curve diagram showing the measurement results of the reflectance of the reflective LCD, the viewing angle of the contrast ratio, and the light source angle (ω).

FIG. 19 is a curve diagram showing measurement results of reflectance of a reflective LCD, viewing angle of contrast ratio, and light source angle (ω).

FIG. 20 is a curve diagram showing the measurement results of the reflectance of the reflective LCD, the viewing angle of the contrast ratio, and the light source angle (ω).

FIG. 21 is a curve diagram showing the measurement results of the viewing angle and light source angle (ω) dependence of the reflectance of the reflective layer of Example 1.

FIG. 22 is a curve diagram showing the measurement results of the reflectance, the viewing angle of the contrast ratio, and the light source angle (ω) of the reflective LCD of Example 1.

23 is a curve diagram showing the measurement results of the reflectance, the viewing angle of the contrast ratio, and the light source angle (ω) of the reflective LCD of Comparative Example 1. FIG.

FIG. 24 is a curve diagram showing the measurement results of the reflectance, the viewing angle of the contrast ratio, and the light source angle (ω) of the reflective LCD of Example 2.

FIG. 25 is a curve diagram showing the measurement results of the reflectance, the viewing angle of the contrast ratio, and the light source angle (ω) of the reflective LCD of Example 3.

FIG. 26 is a curve diagram showing the measurement results of the reflectance, the viewing angle of the contrast ratio, and the light source angle (ω) of the reflective LCD of Example 4.

FIG. 27 is a curve diagram showing the measurement results of the reflectance, the viewing angle of the contrast ratio, and the light source angle (ω) of the reflective LCD of Example 5.

FIG. 28 is a curve diagram showing the measurement results of the reflectance, the viewing angle of the contrast ratio, and the light source angle (ω) of the reflective LCD of Example 6.

29 is a curve diagram showing the measurement results of the reflectance, the viewing angle of the contrast ratio, and the light source angle (ω) of the reflective LCD of Comparative Example 2. FIG.

FIG. 30 illustrates an electrode structure of a substrate used in Example 1 of the present invention, in which (a) is a sectional view and (b) to (e) are plan views.

FIG. 31 is a substrate electrode structure used in Example 2 of the present invention;
And (a) and (b) are plan views for explaining the cell configuration.

32A and 32B are views for explaining an electrode structure of a substrate used in Example 3 of the present invention, in which FIG. 32A is a plan view and FIG.

FIG. 33 illustrates an electrode structure of a substrate used in Example 6 of the present invention, in which (a) to (d) are plan views (where (c) includes a cross-sectional view).

FIG. 34 is a cross-sectional view illustrating a TN type LCD which is a conventional liquid crystal display element.

FIG. 35 is a cross-sectional view illustrating a conventional single-polarizer mode ECB type LCD which is a liquid crystal display device.

FIG. 36 is a PC-GH type LC which is a conventional liquid crystal display device.
Sectional drawing explaining D

FIG. 37 is a cross-sectional view illustrating a GH-HOMO LCD that is a conventional liquid crystal display element.

FIG. 38 is a two-layer type GH-HO which is a conventional liquid crystal display device.
Sectional drawing explaining MO type LCD

FIG. 39 is a cross-sectional view illustrating a GH type LCD that is a conventional liquid crystal display element.

40 is a schematic view for explaining the display principle of the GH type LCD shown in FIG.

FIG. 41 is a schematic diagram illustrating a measurement system for reflectance and contrast ratio.

[Explanation of symbols]

 11 ... Liquid crystal display cell 12 ... Observation side substrate 13 ... Counter substrate 14, 15 ... Electrode 16 ... Liquid crystal layer LM ... Liquid crystal molecule GH ... Dichroic dye 18 ... Reflective layer 19 ... Quarter wave plate 20 ... Translucency Medium layer

Claims (6)

[Claims] 1. A reflective liquid crystal display device comprising: a substrate having at least one transparent electrode; a liquid crystal layer controlled by the electrode; and a reflective layer for reflecting light transmitted through the liquid crystal layer, wherein the reflective layer is reflective. A reflective liquid crystal display device comprising a translucent medium layer having a refractive index of 1.6 or more on its surface. 2. A reflection type liquid crystal having a liquid crystal display cell including at least one substrate having a transparent electrode, a liquid crystal layer controlled by the electrode, and a reflective layer for reflecting light passing through the liquid crystal layer. In the display element, the reflection type liquid crystal display element, wherein the reflective layer is attached to the outer surface of the liquid crystal display cell by using a translucent medium having a refractive index of 1.6 or more as an adhesive. 3. A reflective liquid crystal having a liquid crystal display cell including at least one substrate having a transparent electrode, a liquid crystal layer controlled by the electrode, and a reflective layer for reflecting light passing through the liquid crystal layer. In a display element, a reflective liquid crystal display in which the reflective layer is formed by laminating a translucent medium layer having a refractive index of 1.6 or more on a reflective surface, and is integrated with an outer surface of the liquid crystal display cell via an adhesive. element. 4. The reflective liquid crystal display element according to claim 1, wherein the surface of the reflective layer is a reflective surface or a rough surface in which a large number of convex shapes are arranged in a plane. 5. The liquid crystal layer is made of a nematic liquid crystal to which a dichroic dye is added, and a quarter wavelength plate is provided between the liquid crystal layer and the reflective layer. The reflective liquid crystal display device according to item 1. 6. The reflection type liquid crystal display element according to claim 1, wherein the surface of the reflection layer is made of Al having metallic luster.