JPH09146087A - Reflection type liquid crystal display device and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a display device having a simple structure and high reflec tion characteristic by forming a reflection layer on a substrate having a rugged surface, of which height, depth and width of the ruggedness respectively have specific values or below, and constituting the device in such a manner that the ruggedness formed by a melt method coexists on this rugged surface. SOLUTION: This device has the substrate 1, a liquid crystal layer and the reflection layer for reflecting the light transmitted through this liquid crystal layer. This reflection layer is formed on the substrate having the rugged surface 3 of approximately <=0.5μm in the height, depth and width of the ruggedness. The ruggedness formed by the melt method coexists on this rugged surface 3. Namely, the reflection layer is so formed that the shapes consisting of the spherical crown shapes 2 by the melt method or the similar shapes to obtain an equivalent effect (the min. constituting unit viewed flatly consists of circular, triangular, square, pentagonal, hexagonal, rectangular, elliptic and other shapes and the shapes similar to the spherical crows when viewed sidewise) and the shapes 3 of a rough substrate or the like to provide the extreme value of reflectivity on the front surface coexist flatly.

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 and a method for manufacturing the same.

[0002]

2. Description of the Related Art Liquid crystal display devices (hereinafter abbreviated as LCD) are word processors, personal computers, and projection type T's.
Although it is widely used for V, small TVs, etc., in recent years, a reflective LCD that does not require a backlight has been drawing attention. Reflective type L
Since a CD does not require a backlight for displaying on OA equipment or the like, it can reduce power consumption and is suitable for being carried. Since the reflective LCD utilizes the light of the outside light, if 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, there is a TN type LCD shown in FIG. Liquid crystal cell here
31 is a liquid crystal layer 36 sandwiched between electrodes 34 and 35, and 32 transparent substrates
It consists of 32 and 33, and a pair of polarizing plates 371 on both outer sides of the transparent substrate.
, 372 are attached, and the reflection plate 38 is arranged on the outer surface of one polarizing plate 372. 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 LCD, the optical path L is a polarizing plate.
Pass 371 and 372 four times in total. Of the transmittances of these parts, the transmittance of the polarizing plate is theoretically 50 at least once.
% Or less, and for example, a polarizing plate that functions 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 one polarizing plate mode shown in FIG. 14, and the same reference numerals as those in FIG. 13 indicate the same parts. The same applies to the other figures. Polarizing plate in optical path compared to the TN LCD
The 371 only passes twice and the substrate 32 only twice. As in the case of the TN LCD, the transmittance of the polarizing plate is 50% or less in principle at least once, and actually is 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, a PC-GH type LCD shown in FIG. 15, a GH-HOMO type LCD shown in FIG. 16, and a two-layer type GH-type shown in FIG.
There is a HOMO type LCD and the like. Since neither of the methods uses a polarizing plate, the transmittance is 50% or less at least once as in the mode using the polarizing plate, and the light is brighter as much as the polarizing plate which is actually 40% is not used. Also, the above figure
As with the 14-polarizer single-mode ECB LCD, it is possible to reduce light absorption for two times of the substrate. Therefore, the reflectance is significantly higher than that in the display mode using the polarizing plate.

However, the PC-GH type L shown in FIG.
The CD gives the liquid crystal material of the liquid crystal layer 61 extremely strong chirality to obtain a dark state, and has a molecular arrangement of a strong spiral structure. Reference numeral LM indicates liquid crystal molecules and GH indicates a dye. In order to bring this into a bright state, it is necessary to unwind this strong spiral structure and 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 a state in which the molecular arrangement has a strong helical structure by giving chirality and in a state in which the strong helical structure is unwound by applying an extremely high voltage, and there is a certain degree of stability. Hysteresis occurs in the characteristics (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 LCD shown in FIG.
Since the liquid crystal layer 362 only absorbs the polarized component in one direction,
The brightness in the dark state is more than half that in the bright state, and the contrast ratio is extremely low at 2: 1 or less, which is not practical.

The two-layer GH-HOMO LCD shown in FIG. 17 is different from the GH-HOMO LCD shown in FIG. 16 in that two layers of liquid crystal layers 362 and 362 having crossed orientations are used to polarize light in two directions. Can absorb components and obtain high contrast, but both liquid crystal layers need to be driven,
A parallax corresponding to the thickness of the substrate 2a occurs between the two liquid crystal layers. Therefore, it cannot be applied to high-definition display and the cost becomes high.

Cole and Kashnow (HS Cole and R.
A. Kashnow Applied Physics Letters, vol.30, No.20,
pp619-621 (15 June 1977)) is a GH-HOMO type LCD.
Reflective type L consisting of a quarter-wave plate and a diffuse reflector
Proposing a CD. The structure of this LCD is shown in FIG.
In the reflective LCD shown in FIG. 18, as shown in FIG. 19, incident light Li emitted from the liquid crystal layer 62 of the liquid crystal cell passes through the quarter-wave plate 39 and is reflected by the diffuse reflection plate 38 as Lr. By transmitting again through the quarter-wave plate 39, the phase is halved.
The function to shift and enter the liquid crystal cell 31 again is obtained. Here, only the linearly polarized light changes its phase by the quarter-wave plate 39. Therefore, the two-layer type GH-HO shown in FIG.
The same light control as that of the MO type LCD is obtained by the single liquid crystal layer 362, that is, the single liquid crystal cell 31.

These reflective LCDs necessarily form a reflective layer that reflects light. Generally, the reflection layer is a reflection plate consisting of a reflection surface attached to the outer surface of the cell, and conventionally, a structure in which an aluminum foil is attached to a plastic film, a structure in which aluminum is vapor-deposited on a plastic with unevenness on the surface, White fine paper is used. 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-mentioned display modes, and the substrate on the inner surface of the cell is used. One having a polarizing plate single mode ECB type LCD or P
Application to C-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.

In addition, a display mode in which the reflection plate h made of white high-quality paper and the light reflection in the reflection layer are not involved in the light control for controlling the brightness of the display, that is, the single-polarizer 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 with the light source LCD are low and narrow, and therefore the "contrast ratio" was also poor. Further, 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 single-polarizer mode ECB type L
When a conventional reflection layer is used in a reflection type LCD having a structure in which a quarter wave plate and a diffuse reflection plate are added to a CD or GH-HOMO type LCD, when the light is reflected by the reflection layer, the reflection layer is used as a reflection layer. The polarization state of the incident light is remarkably changed and reflected, which affects the control of display and deteriorates the "contrast ratio" characteristic.

Further, Japanese Patent Application No. 7-22762 is proposed as a reflective layer which maintains the polarization state. The reflective layer has a honeycomb structure of a large number of convex portions having a spherical crown shape, and efficiently reflects light while maintaining polarized light. Further, Japanese Patent Application No. 7-244567 proposes to improve visual field characteristics by mixing two kinds of spherical caps in one pixel.

Further, Japanese Patent Application Laid-Open No. 4-243226 describes that the convex portion is formed by exposing the resist to light and then applying heat to melt it. According to this method, a large-area reflecting plate can be uniformly formed.

[0019]

The reflective layer used in the conventional reflective LCD is the "brightness" and "contrast ratio" characteristics of the display and their viewing angle dependence, the light source and the LCD.
The ECB type LC has a display mode that does not have a sufficient angle dependence with respect to the display mode, and in particular, the light reflection in the reflection layer is not involved in the light control for controlling the brightness of the display, that is, the single-polarizer mode.
When a conventional reflective layer is used for the display mode of a reflective LCD having a configuration in which a quarter-wave plate and a diffuse reflective plate are added to a D or GH-HOMO type LCD, when light is reflected by the reflective layer, The polarization state of the incident light is remarkably changed and reflected by the reflective layer, which affects the control of display and deteriorates the "contrast ratio" characteristic. As a method for improving this problem, Japanese Patent Application No. 7
No. 22762 and Japanese Patent Application No. 7-244567 have been proposed, but the angle dependence of the reflectance is not sufficient.

The present invention solves and solves these problems, and the reflective layer used in the reflective LCD has a "brightness" of display.
It is an object of the present invention to propose a structure, a structure, and a manufacturing method of a reflective layer used in a reflective LCD, which is excellent in "contrast ratio" characteristics, their angular dependence, and the angular dependence between a light source and an LCD.

[0021]

According to the present invention, as a means for solving the above-mentioned problems, a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, and a liquid crystal layer transmitted through the liquid crystal layer. In a reflective liquid crystal display device having a reflective layer that reflects light, the reflective layer has a height, a depth, and a width of unevenness,
A reflective liquid crystal display device is characterized in that it is on a substrate having an uneven surface of approximately 0.5 μm or less, and unevenness formed by a melt method is mixed on this uneven surface.

In another embodiment, the reflective layer has an opening diameter of 0.5 μm or less and a depth of 0.5 μm or less.
A reflective liquid crystal display device is characterized in that unevenness formed by a melt method is mixed on an uneven surface having a plurality of grooves of 0.5 μm or less. In another invention, in a reflective liquid crystal display device having a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, and a reflective layer that reflects light transmitted through the liquid crystal layer, The reflection layer is a reflection-type liquid crystal display device characterized in that unevenness formed by a melt method is formed on a flat mirror surface substrate.

In another embodiment, the reflection layer is a reflection type liquid crystal display device characterized in that the uneven surface performs Bragg reflection.

In another embodiment, the reflecting layer has an uneven surface having a relation of 0 <(area of uneven surface) / (total bottom area of wide surface of unevenness formed by melt method) ≦ 0.5. A reflective liquid crystal display device characterized by the above.

In another embodiment, the unevenness obtained by the melt method is a circle, a triangle, a quadrangle, a pentagon, a hexagon, an octagon, a rectangle or an ellipse in a plan view, and The reflective liquid crystal display device is characterized in that it has a spherical crown shape in a side view.

In another embodiment, the unevenness is a reflection type liquid crystal display device characterized in that a plurality of planar shapes thereof are mixed.

In another embodiment, the unevenness is characterized in that the main material is made of a heat-resistant material and causes Bragg reflection, so that a highly reflective metal is deposited on the main material. It is a reflective liquid crystal display device.

In another embodiment, the reflective layer is
A reflective liquid crystal display device, characterized in that it is formed on one side of the substrate that holds a liquid crystal layer.

In another embodiment, the reflective layer is
The reflective liquid crystal display device is characterized in that the refractive index of the member on the reflective surface is 1.6 or more.

In another embodiment, the liquid crystal layer is
A nematic liquid crystal having dielectric anisotropy is filled with a black dye having dichroism, and the phase of light passing therethrough is shifted by 1/4 wavelength between the liquid crystal layer and the reflection layer.
A reflective liquid crystal display device having a four-wavelength phase difference plate.

In another embodiment, a reflection type liquid crystal display device is characterized in that one polarizing plate is constituted so as to sandwich the reflection layer with the reflection layer.

In another embodiment, a reflection type liquid crystal is characterized in that two polarizing plates are formed so as to hold the liquid crystal layer and the reflection layer is formed outside the polarizing plate. It is a display device.

In another embodiment, a reflective liquid crystal display device is characterized in that a color filter is formed.

In another embodiment, the TFT or T
A reflective liquid crystal display device having an FD active matrix element.

In another embodiment, the reflective layer is
A reflective liquid crystal display device characterized in that it is formed as a pixel electrode on an active matrix element.

In another embodiment, a reflective liquid crystal display device is characterized in that the surface of the reflective layer is made of a highly reflective metal such as aluminum or silver.

In the method of manufacturing a reflection type liquid crystal display device of the present invention, a resist is applied on a substrate having an uneven surface, the unevenness is formed by a predetermined means, and thereafter, the resist is coated with a highly reflective metal. It is characterized by forming a layer.

As another embodiment of the method of manufacturing a reflection type liquid crystal display device of the present invention, the predetermined means is to expose, develop and etch a resist adhered to the surface of a substrate having irregularities to form irregularities, Then, there is a method of manufacturing a reflection type liquid crystal display device, which is characterized by heating and then smoothing the uneven surface.

As another embodiment of the method of manufacturing the reflective liquid crystal display device of the present invention, the method of coating the highly reflective metal is sputtering or vapor deposition. There is a way.

There is a method of manufacturing a reflection type liquid crystal display device according to the present invention, characterized in that pressure is applied or pressure is reduced when heating the unevenness. Further, if a reflection layer, which is a feature of the present invention, is used in a projection screen, a clearer image can be obtained. In this concrete configuration, the project screen has an uneven surface with heights, depths, and widths of about 0.5 μm or less (or an opening diameter of about 0.5 μm and a depth of about 0.5 μm).
The uneven surface is formed by grooves of 0.5 μm), and the uneven surface formed by the melt method is mixed on the uneven surface. Another embodiment of the project screen is equivalent to the reflective liquid crystal display device and the manufacturing method thereof according to the present invention. In the above, the melt method is to form a layer of the heat-meltable substance on the surface of the substrate is patterned in an island shape, a mesh shape, a stripe shape or a disordered shape, to melt the heat-meltable substance layer by heat, the surface tension This is a method of forming a curved surface. The curved surface has a spherical crown shape or the like regardless of the area shape of the portion adhered to the substrate.

The resist itself for patterning can be used as a heat-meltable substance layer or another heat-meltable substance layer can be patterned by using the resist as a mask.

[0042]

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

Rough (refractive irregularity grain size (when the irregularities are considered to be peaks and valleys, the height, depth, width) is 0.5 μm or less) A1 vapor-deposited reflector on the surface of the substrate ( FIG. 2 shows the measurement results of the reflectance characteristics of the N-type electric reflector manufactured by Nitto Denko Corporation.

FIG. 3 shows the results of measuring the reflectance of the reflector prepared by the melt method. Both measurements were performed by the measurement system shown in FIG.

The reflecting plate using the rough substrate has a high frontal reflection characteristic, and a high reflectance is obtained within a certain range. However, the range of the angle (θ) where the high reflectance is obtained is narrow. In contrast, the melting plate shown in FIG. 3 has two extreme values in the viewing angle characteristic of reflectance. This is due to the shape of the reflector by the melt method. FIG.
Is a conceptual diagram for explaining this principle (the principle of taking two extreme values). As shown in Japanese Patent Application No. 7-22762 (Honeycomb reflector plate patent), the surface shape of the reflector plate by the melt method is preferably a spherical crown having a central angle of 90 ° or less. In the case of a spherical crown, as shown in FIG. 5, the smaller the central angle of the spherical crown, which is a symmetric slope when viewed in cross section, the more it can be regarded as a slope, and the dispersion of reflected light is weakened, resulting in a large pole. Will take a value.

Further, by controlling the central angle of the spherical cap (although two extreme values are always generated), the value of θ taking the extreme value can be controlled.

From the above, if a reflecting plate in which a reflecting plate made of a rough substrate and a reflecting plate made by the melt method are combined two-dimensionally is prepared, the reflection characteristic as shown in FIG. 6 can be obtained.

FIG. 1 shows an example of the surface shape of a reflecting plate in which such surface shapes are mixed in a plane. As shown in FIG. 1, the reflector (layer) of the present invention has a substrate 1 having a spherical shape 2 as a first feature by the melt method or a similar shape (the minimum constitutional unit in plan view is a circle). , A triangular shape, a quadrangular shape, a pentagonal shape, a hexagonal shape, a rectangular shape, an elliptical shape and the like, which has a shape similar to a spherical crown when viewed from the side) and an extreme value of the reflectance on the front surface like a rough substrate. The shapes 3 to be obtained are mixed in a plane.

By being mixed, the above-mentioned three extreme values are combined to obtain an excellent visual angle characteristic of reflectance.

When two types of shapes are mixed in this way,
The area mixture ratio may be determined from the respective reflectance characteristics (see FIGS. 2 and 3). Since the above-mentioned two types of reflectors have almost no light absorption due to secondary reflection (reflection in which the number of reflections in the reflection layer is two or more), the total amount of reflected light is substantially the same. Since they are mixed, there is almost no influence on each other. Therefore, if the two characteristics are simply combined by the area ratio, the viewing angle characteristics of the reflector of the present invention shown in FIG. 6 can be obtained. Since the reflector with rough substrate (grain size <0.5 μm) has only one extreme value, the reflectance at that extreme value is more than about twice the reflectance value at the extreme value of the melt method reflector. Becomes Therefore, in order to make the reflectance as constant as possible within a certain viewing angle range and to have a high value, the mixing ratio SR / of the shape of the reflecting surface of the rough substrate and the shape of the reflecting surface by the melt method
It is desirable that SM be 1/2 or less. 120mm x 90mm
Nitto Denko Co., Ltd.'s NPF-F3225, which was cut off, was melted by Tokyo Ohka Kogyo's melt resist (OFPR8).
00: product name) is rubbed coated to have a thickness of 10 μm, exposed and developed to have a pattern shown in FIG.
Pre-baking was performed at 90 ° C. for 30 minutes. After that, 200 ℃
Was heated for 30 minutes at normal pressure (1 atm) to melt the melt resist (OFPR800: trade name). As a result, spherical crown-shaped projections having a central angle of 70 degrees and a radius of 3.5 μm were patterned on the substrate of NPF-F3225M with the melt resist (OFPR800: trade name). The area S _R where the NPF-F3225M (trade name) is exposed and the spherical surface pattern area S of the melt resist
The area ratio of _M was S _R : S _M = 10: 90.

Thereafter, 2000 A of aluminum was vapor-deposited at room temperature to obtain the reflector of the present invention. With this aluminum, the spacing between parallel lattice planes of a group of spatial lattice planes of the crystal is defined as d, and when the reflected wave by this lattice plane group is considered, the glancing angle (the complementary angle of incidence) is θ. , If the wavelength of the incident X-ray or the incident particle is λ and n is a positive integer, then when the Bragg condition 2d sin θ = nλ holds, the reflected waves from the respective lattice planes become in phase and strengthen each other. Diffraction appears in the direction. This is called Bragg reflection (from Iwanami Rikagaku Dictionary 4th edition)).

In order to mix the spherical shape of the spherical shape by the melt method and the shape of the rough substrate (which is completely different from this) in a plane, the spherical shape of the convex portion is formed on the rough substrate by the melt method. Should be provided.

FIG. 7 shows a rough substrate having a width (d2) 8 of 0.
05-0.5 μm, height or depth (d1) 7 is 0.05-0.5
Substrate 1 having a large number of grooves of μm and A on its surface 3
It is a figure explaining the shape of the reflector which vapor-deposited 1 etc. Such shapes are commonly found on commercially available aluminum matte surfaces (behind the shiny side). The surface of the foil is also used as a reflector (eg NPF-F3225 from Nitto Denko Corporation). We will hereinafter refer to these shapes as foil-type irregularities. FIG. 10 shows an example of the reflectance measurement results of an Al reflector having a foil type unevenness (the sample used is the above-mentioned hairline reflector). A in FIG. 8 shows the viewing angle dependence of the reflectance of the groove orientation.
FIG. 8B shows the viewing angle dependence of the reflectance in the direction orthogonal to this.

Similar to the rough substrate described above, if the foil type irregularities and the spherical crown irregularities formed by the melt method are mixed in a plane, the same effect as in the case of the rough substrate can be obtained. In the case of this foil type unevenness, since it has a viewing angle characteristic having azimuth, a mixed reflector also has a characteristic having azimuth. This is useful in applications where the LCD is fixed. Even when this film type unevenness is mixed, the planar mixing ratio SF / SM is 0.5 as with the rough substrate.
The following may be performed.

NPF-F322 manufactured by Nippon Denko Co., Ltd.
5 (trade name) was also formed with the protrusions of the melt method by the method described above.

Further, in the above-mentioned reflective layer in which spherical corrugated irregularities formed by the melt method are partially provided on the irregular substrate,
If two or more shapes having different central angles and bottom radii are mixed in a plane as the spherical crown-shaped concavo-convex shape, the viewing angle characteristics are further improved.

As an example, the central angle is 70 degrees and the bottom radius is 7.0.
When the spherical corrugated part of μm and the central angle of 53.1 degrees and the radius of the bottom surface of 7.0 μm are mixed in a ratio of 1: 1, and they are mixed with the unevenness of the rough substrate described above at 95: 5 (spherical cap: rough). FIG. 9 shows the measurement result of the reflectance of the above, and FIG. 10 shows the measurement result of each reflectance. As can be seen from FIG. 10, the angle θ of the two extreme values occurring in the viewing angle characteristic of reflectance can be controlled by changing the central angle of the reflecting layer having a spherical corrugated shape formed by the melt method. Therefore, by mixing different spherical crown shapes in a plane, the average viewing angle characteristics as shown in FIG. 9 can be obtained. In addition, different viewing angle characteristics can be realized by changing the area ratio of the mixture.

In order to form a reflective layer in which these uneven substrate and the spherical crown-shaped uneven shape formed by the melt method are mixed in a plane, at least the process temperature of the melt method (the temperature required to melt the resist). On the other hand, it is necessary to use a substrate having heat resistance. Therefore, metal or high heat resistant plastic is suitable as the substrate material having irregularities. Among them, the high heat resistant plastic is particularly excellent in lightness and strength (against deformation). As an example,
Polyimide, polyethylene, triacetyl cellulose,
Polyaryate and the like can be mentioned.

FIG. 13 shows an example of a manufacturing flow chart of the reflective layer of the present invention.

As shown in FIGS. 11 (a) to 11 (d), the resist 14 deposited on the uneven surface 3 of the substrate surface having fine unevenness of 0.5 μm or less is exposed through the mask 15 to the exposure 19, phenomenon, If the unevenness 16 is formed by etching and then heated to make the uneven surface gentle, the surface unevenness of the substrate 1 having the uneven surface 3
17 is exposed in the area where the resist pattern does not exist. Further, A (1) or silver 18 is vapor-deposited to obtain Bragg reflection. Therefore, the structure of the reflector of the present invention can be easily obtained.

By using the manufacturing method shown in FIG. 11 and the like, the structure of the reflector of the present invention can be obtained in two shapes as shown in FIGS. 12 (a) and 12 (b).

In any shape, the same effect can be obtained by planarly mixing the above-mentioned two kinds of surface shapes in one display area.

The structure shown in FIG. 16 is a concrete example of the structure shown in FIG. 12 (b).

Further, using the reflector of the present invention prototyped using the above-described manufacturing method, the mold is made of a member having high heat resistance, and the reflector of the present invention is manufactured using this mold. For example, mass production is possible. In this case, a mold may be used to form a substrate having surface irregularities according to the present invention with plastic glass or the like, and a highly reflective metal may be coated on the surface, or a highly reflective metal may be directly poured into the mold. It may be manufactured.

Next, FIG. 12C shows the structure of the reflector of the present invention and the structure of the reflector to which the manufacturing is applied.

The structure of the reflector shown in FIG. 12 (c) is formed on a substrate having two kinds of surface irregularities 17 of the present invention shown in FIG. 1 mixed in a plane (before coating a highly reflective metal. ) By coating the resist 19 etc., the shape of the unevenness is made different from that before the coating. As described above, if the A film 18 is separately coated on the surface irregularities of the present invention, the central angle of the spherical crown, the size of the spherical crown, the irregularities of the base substrate 1 and the like described above can be obtained.
It can be controlled to a value different from that before coating. Therefore, various structures can be realized by this method.

Further, the prototype reflector was polished with sandpaper of 6000 class to form extremely fine irregularities on the surface of the irregularities.

Compared with the state before polishing, it became white in appearance.

FIG. 20 shows a liquid crystal display device 110 of this embodiment. An observation side substrate 112 and a counter substrate 113 thereof have electrodes 114 and 115 respectively on opposite surfaces, and both substrates 112 are provided.
, A liquid crystal cell 111 in which a liquid crystal layer 116 is sandwiched between the liquid crystal cells 111.
And a quarter-wave plate 119 attached to the outer surface of the counter substrate 113.
Further, it has a structure in which the reflection layer (reflection plate) 118 having the above-mentioned configuration is further attached to the surface of the quarter-wave plate 119.

Both the substrates 112 and 113 are glass substrates having a thickness of 0.7 mm, and one substrate, that is, the counter substrate 113 is shown in FIG.
The substrate with the MIM element 120 as shown in (b) and (c). FIG. 20B shows the shape of the electrode 115 of one pixel.
20 (c) shows the shape of the effective display area 1131. The number of pixels is 480 horizontal × 320 vertical, and each pixel p is a MIM element 120.
Is a switching element and has a pixel electrode size of 18
It is 0 μm × 180 μm. Further, a substrate on which the ITO stripe pattern electrode 114 shown in FIGS. 20D and 20E was formed was prepared as the observation side substrate 112. Here, FIG. 20D shows the pattern shape corresponding to one pixel, and FIG.
The shape of the effective display area 1121 is shown. The stripe pattern width of the substrate on which the ITO stripe pattern electrode 114 shown in FIG. 20 (d) is formed is 180 μm (line width 175 μm).
It is.

The alignment film 12 is formed on the two substrates 112 and 113.
1, 122 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. Then, a substrate interstitial material 123 (trade name: Micropearl, manufactured by Sekisui Fine Chemical Co., Ltd.) having a particle size of 8 μm was sprayed on the observation-side substrate 112 at a spraying density of 100 / mm ^2, and 5 mm around the effective display area of the counter substrate. A peripheral seal pattern having a width opening was formed by a screen printing method. The sealing material used here is a one-component epoxy resin (trade name: XN-
21, manufactured by Mitsui Toatsu Chemicals, Inc. Then, the two substrates 112 and 113 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 grain size of the substrate gap material 123. An empty cell used for the liquid crystal display element 110 of this example was obtained. Then, a nematic liquid crystal material having a positive dielectric anisotropy as a liquid crystal material in the empty cell (trade name ZLI-4801-10
0, manufactured by Merck Japan Co., Ltd. Δn = 0.1055. Δε = +
2.0 wt% of a black dye (trade name: LA103 / 4, manufactured by Mitsubishi Kasei Co., Ltd.) was added to 4.9) by a reduced pressure injection method to form a liquid crystal layer 116, and the peripheral seal pattern openings were exposed to ultraviolet rays. Cured resin (trade name: UV-1000, Ltd.)
A liquid crystal cell 111 used in the LCD of this example was obtained by sealing with Sony Chemical.

A quarter-wave plate 119 and the above-mentioned reflection plate 118 were attached to this cell to obtain a device (LCD) 110.

The LCD thus obtained has the observing side substrate 11
Light incident from 2 passes through the liquid crystal cell 111 and is reflected by the reflective layer 118.
The light is reflected by the liquid crystal cell 111, is transmitted again through the liquid crystal cell 111, and is emitted from the substrate on the observation side. Liquid crystal cell that reflects on the reflective layer 118
The light transmitted through 111 was measured, and the reflectance and contrast ratio of the LCD were measured by the measuring device shown in FIG. The measurement is a distance of 30 from the center of the sample 143 position to the position in the normal direction.
A luminance meter 140 is arranged at a height of 2 cm, and two high color rendering fluorescent lamps 141 and 142 which emit light of three wavelengths of red, green and blue are arranged at substantially the same height in a direction forming an angle of 30 ° with the normal direction. do it,
The brightness of a standard diffuser plate (MgO plate) was measured while the illuminance of the 143 part of the sample was 580 lux, and the reflectivity and the contrast ratio of the sample were measured with this brightness being 100%.

MI is applied 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 was a very high value of 65%, and the applied voltage to the liquid crystal layer was 0V and 4V. When the contrast ratio was measured by applying a voltage to the entire surface (all pixels) using the MIM element, it was high at 10: 1 and had little angle dependence like the reflectance, which was conventionally affected by the viewing angle and the environment of the light source. Turned out to be less.

[0075]

As described above in detail, the present invention can realize a reflective liquid crystal display device having a high reflectance and a manufacturing method thereof.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

FIG. 2 is a characteristic diagram of the embodiment of the present invention.

FIG. 3 is a characteristic diagram of an example of the present invention.

FIG. 4 is a simplified diagram of a reflectance measurement system.

FIG. 5 is a schematic diagram illustrating an example of the present invention.

FIG. 6 is a characteristic diagram of an example of the present invention.

FIG. 7 is a characteristic diagram of an example of the present invention.

FIG. 8 is a characteristic diagram of an example of the present invention.

FIG. 9 is a characteristic diagram of an example of the present invention.

FIG. 10 is a characteristic diagram of an example of the present invention.

FIG. 11 is a schematic view of manufacturing process of an embodiment of the present invention.

FIG. 12 is a schematic view of an example of the present invention.

FIG. 13 is a schematic diagram for explaining a conventional technique.

FIG. 14 is a schematic diagram for explaining a conventional technique.

FIG. 15 is a schematic diagram for explaining a conventional technique.

FIG. 16 is a schematic diagram for explaining a conventional technique.

FIG. 17 is a schematic diagram for explaining a conventional technique.

FIG. 18 is a schematic diagram for explaining a conventional technique.

FIG. 19 is a schematic diagram for explaining a conventional technique.

FIG. 20 is a schematic diagram for explaining an example of the present invention.

FIG. 21 is a schematic diagram for explaining a measurement system.

[Explanation of symbols]

 1 ... Substrate 2 ... Spherical crown 3 ... Uneven surface 110 ... Liquid crystal display element 112 ... Observation side substrate 113 ... Counter substrate 116 ... Liquid crystal layer 118 ... Reflection layer

Claims (21)

[Claims] 1. A reflection type liquid crystal display device comprising a pair of substrates, a liquid crystal layer held between the pair of substrates, and a reflection layer for reflecting light transmitted through the liquid crystal layer. The reflection layer is on a substrate having an uneven surface with a height, depth, and width of approximately 0.5 μm or less, and the unevenness formed by the melt method is mixed on this uneven surface. A reflective liquid crystal display device characterized by: 2. The reflective liquid crystal display device according to claim 1, wherein the reflective layer is provided on an uneven surface having a plurality of grooves each having an opening diameter of 0.5 μm or less and a depth of 0.5 μm or less. A reflection type liquid crystal display device characterized in that unevenness formed by a melt method is mixed. 3. A reflection type liquid crystal display device comprising a pair of substrates, a liquid crystal layer sandwiched between the pair of substrates, and a reflective layer for reflecting light transmitted through the liquid crystal layer. The layer is a reflective liquid crystal display device characterized in that unevenness formed by a melt method is formed on a flat mirror substrate. 4. A reflection type liquid crystal display device according to claim 1, 2 or 3, wherein said uneven surface of said reflection layer performs Bragg reflection. 5. The reflection type liquid crystal display device according to claim 1, wherein the reflective layer has a concave and convex surface of 0 <(area of the concave and convex surface) / (a wide bottom area of the concave and convex formed by a melt method). A total of) ≦ 0.5, which is a reflective liquid crystal display device. 6. The reflection type liquid crystal display device according to claim 1, wherein the concavities and convexities formed by the melt method are circular, triangular, quadrangular, pentagonal, hexagonal and octagonal when viewed in plan. A reflective liquid crystal display device, which is one of a prism, a rectangle, and an ellipse, and has a spherical crown shape in a side view. 7. The reflective liquid crystal display device according to claim 6, wherein the unevenness has a plurality of planar shapes mixed therein. 8. The reflection type liquid crystal display device according to claim 1, wherein the unevenness formed by the melt method has a main material made of a heat resistant material and causes Bragg reflection. A reflective liquid crystal display device characterized by being coated with a highly reflective metal. 9. The reflection type liquid crystal display device according to claim 1, wherein the reflection layer is formed on one side of the substrate that holds the liquid crystal layer. Display device. 10. The reflective liquid crystal display device according to claim 1, wherein a member on the reflective surface of the reflective layer has a refractive index of 1.6 or more. Display device. 11. The reflective liquid crystal display device according to claim 1, wherein the liquid crystal layer is formed by adding a black dye having dichroism to nematic liquid crystal having dielectric anisotropy. Further, a reflection type liquid crystal display device is provided between the liquid crystal layer and the reflection layer with a quarter wave retardation plate for shifting a phase of light passing therethrough by a quarter wavelength. 12. The reflection type liquid crystal display device according to claim 11, wherein one polarizing plate is configured so that the liquid crystal layer is sandwiched between the reflection layer and the reflection layer. Liquid crystal display device. 13. The reflective liquid crystal display device according to claim 12, wherein two polarizing plates are formed so as to sandwich the liquid crystal layer, and the reflective layer is formed outside the polarizing plate. A reflective liquid crystal display device characterized by: 14. A reflective liquid crystal display device according to claim 1, further comprising a color filter. 15. The reflective liquid crystal display device according to claim 1, further comprising a TFT or a TFD active matrix element. 16. The reflective liquid crystal display device according to claim 1, wherein the reflective layer is formed as a pixel electrode on an active matrix element. apparatus. 17. The reflective liquid crystal display device according to claim 1, wherein the surface of the reflective layer is made of a highly reflective metal such as aluminum or silver. Reflective liquid crystal display device. 18. A method of manufacturing a reflective liquid crystal display device according to claim 1, wherein a resist is applied on a substrate having an uneven surface, and the unevenness is formed by a predetermined means. A method of manufacturing a reflection type liquid crystal display device, characterized in that after that, a reflective layer is formed by coating with a highly reflective metal. 19. The method for manufacturing a reflective liquid crystal display device according to claim 18, wherein the predetermined means exposes, develops, and etches a resist deposited on the surface of a substrate having irregularities to form irregularities, A method of manufacturing a reflection type liquid crystal display device, which is characterized by comprising heating thereafter and smoothing the uneven surface. 20. The method of manufacturing a reflective liquid crystal display device according to claim 18, wherein the method of coating the highly reflective metal is sputtering or vapor deposition. . 21. The method of manufacturing a reflection type liquid crystal display device according to claim 19, wherein pressure is applied or pressure is reduced when the unevenness is heated.