JPH11160682A - Reflection liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflection color liquid crystal display element capable of making the display sufficiently bright. SOLUTION: An inner side surface of a front substrate 11 is provided with a transparent electrode 13, and an inner surface of a rear side substrate 12 is provided with a reflecting film 14 forming colored layers of magenta, yellow, cyan 16M, 16Y, 16C for color-displaying on the surface by subtractive color mixture, and a transparent electrode 17 formed thereon, and also between the pair of the substrates 11, 12, a liquid crystal polymer composite layer 18 is provided, in which liquid crystal added with dichromatic dye and high polymers are mutually dispersed, and transmission, scattering, and absorption of light are controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Conventionally, most of liquid crystal display devices having a color filter display by utilizing light from a backlight, but recently, external light such as natural light or indoor illumination light has been used. Reflection-type liquid crystal display elements that display by utilizing a color filter having a color filter have come to be seen.

FIG. 8 is a sectional view of a conventional reflection type liquid crystal display device having a color filter. This liquid crystal display element
This is a TN (twisted nematic) mode, and a nematic liquid crystal layer to which a chiral material is added between a pair of front and rear transparent substrates 1 and 2 facing each other with a gap joined via a frame-shaped sealing material (not shown). 7 are provided, polarizing plates 8 and 9 are arranged on the outer surfaces of both substrates 1 and 2, respectively, and a reflecting plate 10 is arranged behind the polarizing plate 9 on the rear side. The polarizing plates 8 and 9 are generally attached to the outer surfaces of the front and rear substrates 1 and 2, respectively.
The reflection plate 10 is attached to the rear surface of the rear polarizing plate 9.

This liquid crystal display element is of an active matrix type using, for example, a TFT (thin film transistor) as an active element. On the inner surface of a rear substrate 2, a plurality of liquid crystal display elements arranged in a matrix in a row direction and a column direction are provided. A transparent pixel electrode 3 is provided. Although omitted in the figure, a plurality of TFTs connected to the plurality of pixel electrodes 3 and a TFT in each row are provided on the inner surface of the rear substrate 2.
And a plurality of data lines for supplying a data signal to the TFTs in each column.

On the inner surface of the front substrate 1, color filters of a plurality of colors corresponding to the respective pixel electrodes 3 are provided.
For example, red, green, and blue color filters 4R, 4G, and 4B are provided alternately, and a single-layer transparent opposing electrode 5 that faces each pixel electrode 3 is provided thereon. .

Further, alignment films 6a and 6b are provided on the inner surfaces of the substrates 1 and 2 so as to cover the electrodes 3 and 5, respectively. Liquid crystal molecules 7a of the liquid crystal layer 7 , 2 in the vicinity of the alignment film 6.
a, 6b, and are twist-oriented at a predetermined twist angle between the substrates 1 and 2.

[0007] The twist angle of the liquid crystal molecules 7a is:
Generally, the angle is approximately 90 °.
Are arranged such that their transmission axes are substantially orthogonal to each other or substantially parallel to each other.

[0008]

However, in the reflection type liquid crystal display device having the above-mentioned conventional color filter, the light absorption by the polarizing plates 8 and 9 and the color filters 4R, 4G and 4B is large, so that the display is not performed. It has a very dark problem.

That is, in the above-mentioned conventional reflection type liquid crystal display device, the light incident from the front surface is first absorbed by the front polarizing plate 8 with the polarization component along the absorption axis, and the light quantity is reduced by almost half. At this point, the amount of light is greatly reduced.

The light transmitted through the front polarizer 8 is absorbed by the color filters 4R, 4G, and 4B in the absorption wavelength band, and the color filters 4R, 4G, and 4B.
It becomes light colored 4B.

The color filters 4R, 4G,
4B passes through the liquid crystal layer 7 and passes through the rear polarizing plate 9.
And the light transmitted through the rear-side polarizing plate 9 is reflected by the reflecting plate 10.
Reflected by the rear polarizer 9, the liquid crystal layer 7, the color filters 4R, 4G, 4B, and the front polarizer 8 and sequentially emitted to the front. In the process, the polarizers 8, 9
In addition, a certain amount of light is absorbed by the color filters 4R, 4G, and 4B.

Further, in the conventional reflection type liquid crystal display device, the color filters 4R, 4G, 4B are provided on the inner surface of the front substrate 1, and the reflection plate 10 is disposed on the rear surface of the rear substrate 2. 8, the distance from the color filters 4R, 4G, and 4B to the reflector 10 is large. Therefore, as shown by the arrow in FIG. 8, one of the light that enters from the front and is reflected by the reflector 10 and exits to the front. The light of the part enters the color filters having different colors on the incident path and the output path, and the light in each absorption wavelength band is absorbed by these color filters and hardly exits.

That is, the reflection type liquid crystal display element is generally inclined to the upper edge side of the screen with respect to the direction perpendicular to the screen so as to mainly take in external light from the upper edge side of the screen (the front surface of the liquid crystal display element). The display is viewed from the front direction, that is, near the direction perpendicular to the screen.

As described above, since external light mainly enters from a direction obliquely inclined with respect to a direction perpendicular to the screen, the incident light is incident on the reflecting plate 10 in an oblique direction and is reflected. In the conventional reflection type liquid crystal display device, since the distance from the color filters 4R, 4G, 4B to the reflection plate 10 is large as described above, the light reflected by the reflection plate 10 is transmitted through the color filter in the incident path. At a position largely deviated from the color filter.

Therefore, as shown in FIG. 8, the light reflected by the reflecting plate 10 includes the light incident on the same color filter as the color filter transmitted through the incident path, and the light transmitted through the incident path. There is light incident on color filters of different colors.

[0016] Of these reflected lights, the light incident on the same color filter as the color filter transmitted through the incident path passes through this color filter and exits, but the color filter transmitted through the incident path has a different color. Light incident on the different color filters hardly emits light because the light in the absorption wavelength band is absorbed by the color filters.

That is, as shown in FIG.
In a liquid crystal display device having blue color filters 4R, 4G, and 4B and displaying a full-color image by additive color mixing, for example, red colored light transmitted through the red color filter 4R is
Other colors, ie, green or blue color filters 4G, 4B
When incident on, most wavelength light of the red colored light,
The light is absorbed by the green or blue color filters 4G and 4B, and almost no emitted light is obtained.

For this reason, the reflection type liquid crystal display device provided with the conventional color filter has an extremely small amount of outgoing light as compared with the amount of external light entering from the front thereof, and the display becomes very dark. .

SUMMARY OF THE INVENTION It is an object of the present invention to provide a reflective type liquid crystal display device which can display an image by utilizing external light and which can sufficiently enhance the display. It is.

[0020]

According to the reflection type liquid crystal display device of the present invention, a transparent electrode is provided on the inner surface of a front substrate of a pair of front and rear substrates facing each other with a gap, and the inner surface of a rear substrate is provided on the inner surface of a rear substrate. A reflective film formed by alternately arranging colored layers of a plurality of colors on the surface, and a transparent electrode formed thereon were provided, and between the pair of substrates, a liquid crystal and a polymer were dispersed each other. A liquid crystal polymer composite layer is provided.

In this reflection type liquid crystal display device, a liquid crystal polymer composite layer in which liquid crystal and a polymer are dispersed is provided between a pair of substrates, and transmission and scattering of light by the composite layer are controlled by the electrodes of both substrates. The display is controlled by applying a voltage between them. According to this reflection type liquid crystal display device, since a polarizing plate is not required, there is no reduction in the amount of light due to absorption of light by the polarizing plate.

Further, in this reflection type liquid crystal display device, since a reflection film formed by alternately arranging a plurality of color layers on the surface is provided on the inner surface of the rear substrate, the light incident from the front surface can be reflected by the rear surface. The inner surface of the side substrate can be colored and reflected by the colored layer, and a bright display can be obtained.

As described above, the reflection type liquid crystal display element of the present invention is a reflection type liquid crystal display element using an external light for display and has a colored layer, but does not require a polarizing plate. , There is no decrease in the amount of light due to the absorption of light by the polarizing plate,
In addition, since a reflection film provided with a colored layer is provided and the incident light is reflected by the reflection film, the light is different in color between the incident path and the exit path as in a liquid crystal display element having a conventional color filter. Without being incident on the color filter and absorbing the light in the absorption wavelength band of both color filters,
The display can be made sufficiently bright by emitting the incident light at a high emission rate.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The reflective liquid crystal display device of the present invention comprises a polarizing plate comprising a liquid crystal polymer composite layer in which liquid crystal and a polymer are dispersed between a pair of substrates. Further, by providing a reflection film formed by alternately arranging a plurality of color layers on the surface on the inner surface of the rear substrate, light incident from the front surface is efficiently reflected by the reflection film, and To make the display sufficiently bright.

In the reflection type liquid crystal display device of the present invention,
A plurality of colored layers formed on the reflective film, magenta used for performing color display by subtractive color mixing,
Desirably, color filters of three colors of yellow and cyan are used. The color filters of these colors have a wider transmission wavelength band than red, green and blue color filters for performing color display by additive color mixture. Since the light transmittance is high, the display can be made brighter.

The reflective film may be formed by applying a color filter made of a color resist or the like to the surface of a metal film or the like to form the colored layer. Preferably, the coloring layer is formed by adsorbing a coloring substance on the porous layer of the metal film. Because this reflective film is the one that colored the surface of the metal film,
Very high reflectivity, so that the display can be brighter.

Further, the surface of the reflective film may be formed so that the surface of the colored layer is flat. However, if the surface of the colored layer is formed as a concave-convex surface having a mountain-shaped cross section, the inclination angle of the inclined surface may be selected. Thereby, the colored reflected light from the reflective film can be emitted in a predetermined direction, and the observation luminance of display from that direction can be increased.

In the case where the surface of the reflective film is formed as a concave and convex surface having a mountain-shaped cross section, it is preferable to provide an insulating film having a flat surface on the colored layer of the reflective film and form a transparent electrode thereon. Desirably, the thickness of the liquid crystal layer and the distance between the electrodes of both substrates are made substantially uniform, so that uniform electro-optical characteristics can be obtained.

[0029]

1 to 3 show a first embodiment of the present invention. FIG. 1 is a sectional view of a reflection type liquid crystal display device, and FIG. 2 is an enlarged view of a part of FIG. The reflection type liquid crystal display element of this embodiment is of an active matrix type using a TFT as an active element, and a pair of front and rear substrates 1 opposed to each other with a gap joined via a frame-shaped sealing material (not shown).
A plurality of transparent pixel electrodes 13 arranged in a matrix in the row direction and the column direction are provided on the inner surface of the front substrate (transparent substrate made of glass or the like) 11 of the substrates 1 and 12. Although not shown in the figure, the front substrate 1
A plurality of TFTs respectively connected to the plurality of pixel electrodes 13, a plurality of gate lines for supplying a gate signal to the TFTs in each row, and a plurality of data for supplying a data signal to the TFTs in each column are provided on an inner surface of the pixel 1. Lines are provided.

Further, a rear substrate (for example, a glass substrate) 12
On the inner surface, there are provided a plurality of colored layers corresponding to the respective pixel electrodes 13, for example, magenta, yellow, and cyan color filters 16M and 16Y used for performing color display by subtractive color mixing. , 16C are alternately arranged, and a reflection film 14 is provided on the reflection film 14 (color filters 16M, 16Y, 1).
6C), a single film-shaped transparent counter electrode 17 facing each pixel electrode 13 is provided. In this embodiment, the color filters 16M and 16M of the reflection film 14 are used.
Although the counter electrode 17 is formed directly on Y and 16C, the color filters 16M, 16Y and 16C may be covered with a transparent protective insulating film, and the counter electrode 17 may be formed thereon.

The reflective film 14 is formed by depositing a high-reflectance metal film 15 made of aluminum or the like on the rear substrate 12 by a sputtering apparatus or the like, and then, forming a fine uneven surface by sandblasting or the like (see FIG. 2). ), A magenta, yellow, and cyan color filters 16M, 16Y, and 16C are formed by applying a photosensitive color resist to the surface of the metal film 15 and patterning the surface into a predetermined pattern by exposure and development. These color filters 16 are formed by forming them sequentially.
The surfaces of M, 16Y, and 16C are flat surfaces.

In a region between the pair of substrates 11 and 12 surrounded by the sealing material, a liquid crystal polymer composite layer 1 in which a liquid crystal and a polymer to which a dichroic dye is added is dispersed.
8 are provided.

In this embodiment, the liquid crystal polymer composite film 18 and the electrodes 13 and 17 on the inner surfaces of the substrates 11 and 12 are in direct contact with each other, but an insulating film which covers the electrodes 13 and 17 transparently is used. It may be covered.

In the liquid crystal polymer composite layer 18, for example, a polymer material which undergoes a polymerization reaction by ultraviolet rays and a dichroic dye are added to a region surrounded by the sealing material between the pair of substrates 11 and 12. A mixed solution with a nematic liquid crystal having a positive dielectric anisotropy is filled, and a layer of the mixed solution is added to the front substrate 11.
The polymer layer 19 is formed by irradiating ultraviolet rays from the front side of the polymer layer to cause phase separation between the liquid crystal and the polymer by photopolymerization of the polymer material. The liquid crystal molecules a and the dichroic dye molecules b in each of the liquid crystal domains 20 have a random structure in the absence of an electric field. Is facing the right direction.

This reflection type liquid crystal display element uses natural light or external light such as indoor illumination light to reflect light incident from the front with the reflection film 14 on the inner surface of the rear substrate 12 for display. Light transmission is controlled by applying an electric field to the liquid crystal polymer composite layer 18.

That is, this liquid crystal display element controls the voltage applied between the electrodes 13 and 17 in each pixel region where each pixel electrode 13 and the counter electrode 17 are opposed to each other, so that the liquid crystal polymer composite The display is driven by controlling the electric field applied to the layer 18.
Liquid crystal molecules a and dye molecules b of each liquid crystal domain 20 of FIG.
Is in a random direction in the absence of an electric field,
In the absence of an electric field, light transmitted through the composite layer 18 is scattered by refraction at the interface between the polymer layer 19 and the liquid crystal domain 20 and the birefringence effect of the liquid crystal molecules a, and the scattered light is diffused by the dye molecules b. It is absorbed, and the display of the pixel area becomes almost black and dark.

When a voltage is applied between the electrodes 13 and 17, the electric field causes the liquid crystal molecules a of the liquid crystal domain 20 to orient with respect to the surfaces of the substrates 11 and 12, and the dye molecules b. Also rises,
Light scattering and absorption by the liquid crystal polymer composite film 18 are reduced.

Therefore, when an electric field is applied, the incident light from the front surface passes through the liquid crystal polymer composite layer 18 and passes through the rear substrate 12.
The reflected light is reflected by the reflective film 14 on the inner surface of the pixel, and the reflected light passes through the composite layer 18 and is emitted to the front surface, so that the display of the pixel region becomes bright.

In this liquid crystal display device, the magenta, yellow, and cyan color filters 16M, 16 corresponding to the respective pixel regions are formed on the surface of the reflection film 14.
Since Y and 16C are alternately arranged, the light reflected by the reflection plate 14 is applied to the color filters 1 of the respective colors.
6M, 16Y, and 16C, which are colored lights of magenta, yellow, and cyan. The liquid crystal polymer composite layer 18 is controlled by controlling the voltage applied between the electrodes 13 and 17 of the substrates 11 and 12. The degree of light transmission, scattering and absorption can be changed to control the light transmittance in multiple stages, so that various colors can be expressed by mixing these magenta, yellow, and cyan colored lights. it can.

FIG. 3 is a CIE chromaticity diagram showing the range of expression colors of the liquid crystal display element. In the drawing, W is an achromatic color point. As shown in the chromaticity diagram, the magenta, yellow, and cyan colored lights M, Y, and C colored to the colors of the color filters 16M, 16Y, and 16C of the respective colors have chromaticity coordinates as shown in the figure. The color represented by the mixture of the light M, Y, and C is a color in the chromaticity range shown by hatching in the figure. Therefore, according to the liquid crystal display device, a multicolor color composed of many colors is used. Images can be displayed.

As described above, the reflection type liquid crystal display device has:
A liquid crystal polymer composite layer 18 in which liquid crystal and a polymer are mutually dispersed is provided between the pair of substrates 11 and 12.
The transmission, scattering and absorption of light by the two substrates 11 and 12
The display is controlled by applying a voltage between the electrodes 13 and 17. According to this liquid crystal display device, a polarizing plate, which is indispensable for a conventional TN mode liquid crystal display device, is not required. Therefore, there is no decrease in the amount of light due to the absorption of light by the polarizing plate.

Further, in the above liquid crystal display device, the color filters 16M, 16M
Since the reflection film 14 on which the Y and 16C are formed is provided, the light incident from the front can be colored by the color filters 16M, 16Y and 16C on the inner surface of the rear substrate 12 and the colored light can be reflected. . Therefore, as in the conventional color display element, the light that enters from the front surface, is reflected by the reflective film 14, and exits to the front surface is incident on the color filters having different colors between the incident path and the exit path, and the two color filters are used. Light in the absorption wavelength band of the filter is not absorbed.

That is, as described in the section of [Problems to be Solved by the Invention], the reflective liquid crystal display element is designed to take in external light mainly from the upper edge side of the screen (the front surface of the liquid crystal display element). A direction inclined toward the upper edge of the screen with respect to a direction perpendicular to the screen is used in a direction in which bright external light is obtained, and the display is observed from the front direction, that is, near the direction perpendicular to the screen.

For this reason, the light incident on the liquid crystal display element from the front is mainly incident on the liquid crystal display element from a direction obliquely inclined with respect to the direction perpendicular to the screen as shown by the arrow in FIG. The display element has a reflective film 1 on the inner surface of the rear substrate 12.
4 and the reflective film 14 has a structure in which the color filters 16M, 16Y and 16C are formed on the surface of the metal film 15, so that the color filters 16M and 1C are formed.
Light transmitted through 6Y and 16C and reflected on the surface of the metal film 15 does not enter a color filter of another color.

For this reason, the light reflected by the reflection film 14 enters the color filter 16
M, 16Y, and 16C absorb and color the light in the absorption wavelength band, and when the light is emitted from the reflective film 14, the light in the absorption wavelength band is absorbed by the same color filters 16M, 16Y, and 16C, and the color purity is higher. It becomes colored light, which is emitted to the front of the liquid crystal display element.

Therefore, the above-mentioned liquid crystal display element is of a reflection type for displaying by utilizing external light and has a color filter. However, since a polarizing plate is not required, the light from the polarizing plate is not required. There is no decrease in the amount of light due to the absorption of light, and the incident light is colored and reflected by the colored layer formed on the surface of the reflective film, so that the incident light is emitted at a high emission rate and the display is sufficiently bright. can do.

In addition, the liquid crystal display element has magenta,
Three color filters 16M, 16 of yellow and cyan
A color display is performed by color mixture using Y, 16C. These color filters 16M, 16Y, 16
C has a wider transmission wavelength band and a higher light transmittance than the red, green, and blue color filters used for performing color display by additive color mixture, so that the display can be made brighter.

In the above embodiment, the reflection film 14
The surface of the metal film 15 formed on the rear substrate 12 is processed into a fine irregular surface, and the surface of the metal film 15 is formed of a photosensitive color resist, and is formed of a magenta, yellow, and cyan color filter 16M. , 16Y, 16C, the metal film 15 and the color filter 1 are formed.
Adhesion strength with 6M, 16Y and 16C is sufficient.

FIGS. 4 and 5 show a second embodiment of the present invention. FIG. 4 is a sectional view of a reflection type liquid crystal display device. In the reflection type liquid crystal display device of this embodiment, a coloring material composed of metal ions is adsorbed on the porous layer of the metal film 22 having a porous layer formed on the inner surface of the rear substrate 12 by anodizing. , Yellow and cyan colored layers 23M, 23Y, and 23C are formed on the reflective film 21 (the color filters 23M and 2C).
3Y, 23C), a transparent insulating film 23 is formed thereon, and a counter electrode 17 is provided thereon.

The liquid crystal display device of this embodiment is an active matrix display device of a phase change mode, and the other structure is the same as that of the first embodiment except for the reflection film 21. Therefore, the overlapping description is given the same reference numeral in the figure and omitted.

FIG. 5 is a cross-sectional view in each step showing a method of forming the reflection film 21. The reflection film 21 is formed as follows. First, as shown in FIG. 5A, a high-reflectance metal film 22 made of aluminum or the like is formed on the rear substrate 12 by a sputtering apparatus or the like.

Next, as shown in FIG. 5B, a photosensitive resist is applied on the metal film 22 and is exposed and developed, so that one of the colors magenta, yellow and cyan is obtained. Colored layer, for example, magenta filter 2
A resist mask 25 covering the metal film 22 is formed except for the region where the 3R is formed. In this state, the surface of the metal film 22 is subjected to anodizing treatment to form a magenta colored layer forming region on the surface of the metal film in a porous state. The material layer 22a.

In the anodic oxidation treatment of the metal film 22, the substrate 12 is immersed in an electrolytic solution, and a direct current is applied between the metal film 22 and a cathode disposed in the electrolytic solution using the metal film 22 as an anode. The voltage is applied, and the oxidation depth (the thickness of the formed porous layer 22a) is controlled by the voltage application time.

Next, while the resist mask 25 is left, the substrate 12 is immersed in an electrolytic solution in which metal ions (for example, Au ions) for coloring magenta are dissolved, and electroplating is performed. Porous layer 2 of membrane 22
The metal ions are adsorbed to the holes 2a to form a magenta colored layer 23M as shown in FIG. 5C.

Thereafter, the magenta colored layer 23M is formed.
In the same manner as in the formation, the surface of the metal film 22 is made porous by anodic oxidation of the region for forming the yellow colored layer, and the porous layer is electroplated with metal ions (for example, Ag ions) for coloring yellow. The yellow colored layer 23Y is formed by the adsorption, then the cyan colored layer forming region is made porous by anodic oxidation, and electroplating of the porous layer with cyan-colored metal ions (for example, Cu ions). Then, a cyan colored layer 23C is formed by the adsorption by the, and the reflection film 21 is completed as shown in FIG.

Since the reflective film 21 is obtained by coloring the surface of the metal film 22 to form the colored layers 23M, 23Y, and 23C, as shown by arrows in FIG. The light in the absorption wavelength band of the colored layers 23M, 23Y and 23C is absorbed, and the colored layers 23M, 23Y and 23C are absorbed.
The light in the wavelength band that is not absorbed by the light is converted into colored light and reflected on the surface of the reflective film.

Therefore, according to the liquid crystal display device of this embodiment, since the reflection film 21 reflects light on the surface thereof, the reflectance is very high, and high-reflectance colored reflected light can be obtained. According to the liquid crystal display device of the embodiment, the display can be made brighter than in the first embodiment.

In the reflection film 21, the surface of the metal film 22 is formed into a porous layer 22a by anodic oxidation treatment, and a coloring material composed of metal ions is adsorbed on the porous layer 22a to color magenta, yellow, and cyan. Layers 23M, 23Y,
23C, the colored layers 23M, 23
Y and 23C are excellent in heat resistance and light resistance, and the colored layer surface is flat.

FIGS. 6 and 7 show a third embodiment of the present invention. FIG. 6 is a sectional view of a reflection type liquid crystal display device. In the reflection type liquid crystal display device of this embodiment, the coloring material composed of metal ions is adsorbed on the porous layer of the metal film 31 whose surface is made porous by anodizing on the inner surface of the rear substrate 12. , Yellow, and cyan coloring layers 32M, 32Y, and 32C, and a reflection film 30 having a structure in which the surfaces of these coloring layers 32M, 32Y, and 32C have a concave-convex surface having a mountain-shaped cross section. A transparent insulating film 33 having a flat surface is provided on the colored layers 32M, 32Y, and 32C, and the counter electrode 17 is provided thereon.

The liquid crystal display device of this embodiment is an active matrix display device of a phase change mode. Except for the reflection film 30, the other components are the same as those of the first and second embodiments. Since they are the same, the same description will be given the same reference numerals in the drawings and will be omitted.

FIGS. 7A to 7C are cross-sectional views showing steps of a method for forming the reflection film 30. The reflection film 30 is formed as follows. First, as shown in FIG. 7A, a high-reflectance metal film 31 made of aluminum or the like is formed on the rear substrate 12 by a sputtering device or the like, and the surface is processed by an etching process or the like. A plurality of horizontally long convex portions having a mountain-shaped cross section along the horizontal axis direction of the screen of the liquid crystal display element are formed as concavo-convex surfaces continuous in the width direction.

It is to be noted that each mountain-shaped convex portion of the uneven surface is provided with a colored layer 32 R, 32 of each color formed on the surface of the metal film 31.
G and 32B are formed at a pitch P1 smaller than the arrangement pitch P. Further, each of the mountain-shaped convex portions has an inclination angle θ1 of one of the slopes facing the upper edge side (left side in the drawing) of the screen, which is the main direction of external light, among the slopes on both sides thereof.
Is smaller than the inclination angle θ2 of the other slope (both are angles with respect to the surface of the substrate 12), and the width of the one slope is wider than the width of the other slope.

Next, as shown in FIG. 7B, a photosensitive resist is applied on the metal film 31 and is exposed and developed to obtain one of magenta, yellow and cyan. Colored layer, for example, a magenta colored layer 3
A resist mask 34 covering the metal film 31 is formed except for the 2M formation region, and in this state, the surface of the metal film 31 is subjected to anodizing treatment to form a magenta colored layer formation region on the metal film surface in a porous state. The material layer 31a.

Next, while the resist mask 34 is left, the porous layer 21 of the metal film 21 is formed by electroplating.
A metal ion to be colored magenta is adsorbed in the hole of a,
As shown in FIG. 7C, a magenta colored layer 32M is formed.

Thereafter, the magenta colored layer 32M
In the same manner as in the formation, the yellow color layer is formed by anodic oxidation of the yellow colored layer forming region on the surface of the metal film 31 and the metal ions to be colored yellow are adsorbed to the porous layer by electroplating. Forming a colored layer 32Y of
Next, the cyan colored layer 32 is made porous by anodic oxidation of the cyan colored layer forming region, and the metal layer coloring cyan is adsorbed to the porous layer by electroplating.
C is formed to complete the reflection film 30 as shown in FIG. 7D, and then a transparent insulating film 33 having a flat surface is formed on the reflection film 30.

The reflection film 30 thus formed
The surface of the colored layer 32M, 32Y, 32C of each color is an uneven surface having at least one or more mountain-shaped protrusions. Of the slopes on both sides of the mountain-shaped protrusions, The width of one slope facing the upper edge side of the screen in the capture direction is wider than the width of the other slope.

According to the liquid crystal display device of this embodiment, the reflectivity of the reflection film 30 is very high, so that high-brightness colored reflected light can be obtained. Therefore, the display can be made brighter than in the first embodiment. can do.

In this embodiment, the reflection film 30
Since the surfaces of the colored layers 32M, 32Y, and 32C of the respective colors are each an uneven surface having at least one or more chevron-shaped convex portions, by selecting the inclination angles θ1 and θ2 of the slopes, Colored reflected light in a predetermined direction,
For example, as shown by an arrow in FIG. 5, light can be emitted in the front direction (near the direction perpendicular to the screen), and the observation brightness of display from that direction can be increased.

In this embodiment, the color layer 32
Although the surfaces of M, 32Y, and 32C are concave and convex with a mountain-shaped cross section, an insulating film 33 having a flat surface is provided on the colored layers 32M, 32Y, and 32C, and the counter electrode 17 is formed thereon. , The thickness of the liquid crystal layer 19 and the substrates 11, 1
The distance between the two electrodes 13 and 17 can be made substantially uniform, and thus uniform electro-optical characteristics can be obtained.

That is, the colored layers 32M, 32Y, 3
In the case where the surface of 2C is an uneven surface, if the counter electrode 17 is formed thereon without flattening the surface, the liquid crystal layer 19
And the distance between the electrodes 13 and 17 of the two substrates 11 and 12 are different between a region corresponding to the convex portion of the uneven surface and a region corresponding to the concave portion, and the voltage applied between the electrodes 13 and 17 is different. On the other hand, the strength of the electric field actually acting on the liquid crystal layer 19 is different between the region corresponding to the convex portion and the region corresponding to the concave portion. Although the image quality deteriorates, as in this embodiment, the insulating film 3 is formed on the coloring layers 32M, 32Y, and 32C.
If the counter electrode 17 is formed on the flattened layer 3 and the counter electrode 17 is formed thereon, it is possible to display an image of good quality with uniform electro-optical characteristics.

Further, according to this embodiment, the surfaces of the colored layers 32M, 32Y, and 32C of the respective colors of the reflection film 30 are concave and convex with a mountain-shaped cross section, and the light reflected by the concave and convex is
The light is emitted in the display observation direction (for example, the front direction) as indicated by the solid line arrow in FIG. 5, but the surface (the interface with the counter electrode 17) of the insulating film 33 or the counter electrode 1
The light that is incident on the surface and the like at a total reflection angle and reflected on that surface is reflected obliquely at a reflection angle corresponding to the incident angle, as indicated by the arrow indicated by the broken line in the figure. The reflected light is not visible to the observer, and therefore, the outside scene does not appear on the surface of the insulating film 33 or the surface of the counter electrode 17.

Each of the reflection films 21 and 30 of the second and third embodiments uses metal ions as a coloring substance to be adsorbed on the porous layers 22a and 31a of the metal films 22 and 31. However, the coloring substance may be a dye or pigment made of an organic or inorganic substance.

The liquid crystal display devices of the first to third embodiments have three colored layers 3 of magenta, yellow and cyan.
2M, 32Y, 32C, and these colored layers 32M,
A color image is displayed by mixing the emitted lights of magenta, yellow, and cyan colored in the colors of 32Y and 32C. The color filter is, for example, a red, green, and blue color that performs color display by additive color mixing. A filter may be used.

Further, in each of the above embodiments, a dichroic dye was added to the liquid crystal of the liquid crystal polymer composite film 18, but the liquid crystal polymer composite film 18 used liquid crystal to which no dichroic dye was added. Alternatively, the light transmission and scattering may be controlled.

The present invention is not limited to the active matrix type using TFTs as active elements, but also the active matrix type reflection type liquid crystal display elements using MIMs as active elements, and the scanning electrodes extending in one direction on one substrate. Can be applied to a simple matrix type reflection type liquid crystal display element or the like in which a plurality of signal electrodes are provided in parallel with each other and a plurality of signal electrodes are provided on the other substrate in a direction intersecting with the scanning electrodes.

[0076]

According to the reflection type liquid crystal display device of the present invention, a transparent electrode is provided on the inner surface of the front substrate among a pair of front and rear substrates facing each other with a gap, and a plurality of substrates are provided on the inner surface of the rear substrate. A reflective film formed by alternately arranging colored layers of a color and a transparent electrode formed thereon, and a liquid crystal polymer composite layer in which liquid crystal and a polymer are dispersed between the pair of substrates. According to this reflective liquid crystal display element, a polarizing plate is unnecessary, and light incident from the front is colored by the colored layer on the inner surface of the rear substrate and the colored light is reflected. can do.

Therefore, this reflection type liquid crystal display device has:
Although it is a reflective color display element that displays using external light, it does not require a polarizing plate, so there is no reduction in the amount of light due to the absorption of light by the polarizing plate, and the incident light is emitted at a high emission rate. Thus, the display can be made sufficiently bright.

In the reflection type liquid crystal display device of the present invention,
The colored layers of the plurality of colors are preferably three color filters of magenta, yellow, and cyan used for performing color display by subtractive color mixture, and the color filters of these colors are color display by additive color mixture. Since the transmission wavelength band is wider than that of the red, green, and blue color filters for performing the above, and the light transmittance is high, the display can be made brighter.

Further, it is preferable that the reflection film is formed by adsorbing a coloring substance on the porous layer of a metal film whose surface is made porous by anodizing treatment. Since the surface of the film is colored to form a colored layer, the reflectivity is extremely high, and thus the display can be made brighter.

Further, in this reflection type liquid crystal display element, if the surface of the colored layer of the reflective film is formed as a concave-convex surface having a mountain-shaped cross section, the colored reflected light from the reflective film is selected by selecting the inclination angle of the inclined surface. The light is emitted in a predetermined direction, and the observation brightness of the display from that direction can be increased.

In the case where the surface of the colored layer is formed as a concave and convex surface having a mountain-shaped cross section, an insulating film having a flat surface is provided on the colored layer, and a transparent electrode is formed thereon. By making the layer thickness and the spacing between the electrodes of both substrates almost uniform,
Uniform electro-optical characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a reflective liquid crystal display device showing a first embodiment of the present invention.

FIG. 2 is an enlarged view of a part of FIG.

FIG. 3 shows a CI indicating a range of expression colors in the first embodiment.
E chromaticity diagram.

FIG. 4 is a sectional view of a reflective liquid crystal display device showing a second embodiment of the present invention.

FIGS. 5A to 5C are cross-sectional views in respective steps showing a method of forming a reflective film in a second embodiment.

FIG. 6 is a sectional view of a reflective liquid crystal display device according to a third embodiment of the present invention.

FIGS. 7A and 7B are cross-sectional views in respective steps showing a method of forming a reflective film in a third embodiment.

FIG. 8 is a sectional view of a conventional reflective liquid crystal display device.

[Explanation of symbols]

 11, 12 ... substrate 13 ... pixel electrode 14, 21, 30 ... reflective film 15, 22, 31 ... metal film 22a, 31a ... porous layer 16M, 23M, 32M ... magenta colored layer 16Y, 23Y, 32Y ... yellow Colored layers 16C, 23C, 32C: Cyan colored layer 17: Counter electrode 18: Liquid crystal polymer composite layer 19: Polymer layer 20: Liquid crystal domain a: Liquid crystal molecules b: Dye molecules 33: Flat surface insulation film

Claims (5)

[Claims] 1. A transparent electrode is provided on an inner surface of a front substrate of a pair of front and rear substrates facing each other with a gap therebetween, and a plurality of color layers of a plurality of colors are alternately arranged on the surface of an inner surface of a rear substrate. A reflective film, and a transparent electrode formed thereon are provided, and between the pair of substrates, a liquid crystal polymer composite layer in which a liquid crystal and a polymer are mutually dispersed is provided. Reflective liquid crystal display device. 2. The reflection type liquid crystal according to claim 1, wherein the color layers of a plurality of colors are color filters of three colors of magenta, yellow, and cyan for performing color display by subtractive color mixture. Display element. 3. The reflection film comprises a metal film whose surface is made porous by anodizing treatment, and a coloring layer formed by adsorbing a coloring substance on the porous layer. Item 2. The reflective liquid crystal display device according to item 1. 4. The reflection type liquid crystal display device according to claim 1, wherein the surface of the reflection film has an uneven surface having a mountain-shaped cross section. 5. The reflective liquid crystal display device according to claim 4, wherein an insulating film having a flat surface is provided on said reflective film, and said transparent electrode is formed thereon.