JPH11337717A - Color filter substrate and reflection type liquid crystal display using this substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color filter substrate and a liquid crystal display using this substrate which have solved a problem in a conventional reflection color liquid crystal display that light which is made obliquely incident and passes only an essential color and is emitted, and light which is made obliquely and passes colors of adjacent picture elements and is emitted overlap to cause color mixture to reduce the color purity because of strong color dependence upon visual angle. SOLUTION: With respect to the structure of a color filter used in a reflection liquid crystal display, sections of RGB color elements of the color filter are formed like a convex lens, and reflected light 151 and 152 of obliquely incident light 141 and 142 are condensed in the normal direction of a panel to prevent color mixture between adjacent picture elements.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a color filter and, more particularly, to a reflection type liquid crystal display device which performs color display using the color filter.

[0002]

2. Description of the Related Art A color liquid crystal display device generally realizes color display by forming a fine color filter inside a panel. The color filter is formed by forming an organic film containing a dye or a pigment on a substrate and finely processing the film by photolithography. When performing multi-color display, red,
In general, green and blue color filters are formed for each dot.

[0003] In recent years, attention has been focused on a reflection type color liquid crystal display device aiming at high display quality such as brightness and high color purity even in a dark environment with the attractiveness of low power consumption.

The color filter of the reflection type color liquid crystal display device is formed by photolithography using an organic film containing a dye or a pigment similarly to the color filter of the transmission type color liquid crystal display device. However, since reflective color liquid crystal display devices need to effectively utilize external light, the color filters used are required to have high transmittance, and materials having lower color purity than the color filter materials of transmissive color liquid crystal display devices are required. And the film forming conditions are usually different.

FIG. 2 is a plan view (a) of a structure of a conventional reflection type liquid crystal display device and a sectional view (b) of FIG. On the color filter substrate 200, R (red), G (green),
B (blue) color filters 202, 203, 204,
Further, the strip-shaped transparent common electrode 20 via the protective film 205
An alignment film 207 is formed on 6. On the other hand, a strip-shaped transparent segment electrode 212 is provided on the counter substrate 210, and an alignment film 217 is formed thereon. Liquid crystal 230 is sealed between the two substrates with a specific gap. A polarizing plate 208 is provided on one color filter substrate 200, and a polarizing plate 218 is provided on the other counter substrate 210.
And a reflection plate 219 are attached so as to match the designated transmission and absorption axes, respectively, and display is performed by controlling the amount of reflected incident light of the surrounding environment by an electric field between electrodes applied to the liquid crystal.

[0006]

However, the conventional reflection type liquid crystal display device has a strong viewing angle dependence on color. That is, as shown in FIG.
Reference numeral 41 denotes an outgoing light 251 passing through only the original color, and an outgoing light 252 passing through the color of an adjacent pixel like the incident light 242.
However, there is a drawback that they overlap and cause color mixture.

Therefore, the present invention provides a structure of a color filter for preventing color mixture between adjacent pixels by condensing obliquely incident light in the normal direction of the panel and a reflection type liquid crystal display device using the same. The purpose is to:

[0008]

A color filter substrate according to claim 1, wherein a color filter is provided on the substrate, and a protective film and a drive electrode are provided thereon. Is a structure having a convex lens shape.

According to the above structure, in the structure in which the driving electrodes are provided on the color filter and the protective layer, the color filter plays the role of a lens, and condenses obliquely incident light in the normal direction of the panel. This has the effect of preventing color mixing between adjacent pixels.

[0010] The color filter substrate according to claim 2 is
In a color filter substrate in which a drive electrode is provided on a substrate and a color filter and a protective film are formed thereon,
The color filter has a convex lens shape in cross section.

According to the above structure, in the structure in which the drive electrode is disposed below the color filter and the protective layer, the color filter functions as a lens and collects obliquely incident light in the normal direction of the panel. This has the effect of preventing color mixing between adjacent pixels by illuminating.

The color filter substrate according to claim 3 is
The color filters are arranged in a mosaic or delta arrangement on the substrate, and a cross-sectional shape of the color filters has a curvature at a part near an end thereof.

According to the above arrangement, the portion having the curvature near the pattern end of the mosaic or delta-arranged color filter functions as a lens, and collects obliquely incident light in the normal direction of the panel and adjoins it. This has the effect of preventing color mixing between pixels.

The color filter substrate according to claim 4 is
The color filters are arranged in stripes on the substrate, and a cross-sectional shape of the color filters has a curvature in a part near an end thereof.

According to the above configuration, a portion having a curvature at the periphery of the pattern of the color filter arranged in stripes functions as a lens, and condenses obliquely incident light in the normal direction of the panel to form a pixel between adjacent pixels. This has the effect of preventing color mixing.

The color filter substrate according to claim 5 is
The refractive index of the color filter is higher than the refractive index of the protective film.

According to the above configuration, the function of the lens of the color filter is further improved, and the light obliquely incident is more concentrated in the normal direction of the panel to prevent color mixing between adjacent pixels. It enhances the effect.

According to a sixth aspect of the present invention, there is provided a reflective liquid crystal display device comprising: a first substrate comprising the color filter substrate according to any one of the first to fifth aspects; A second substrate having a transparent drive electrode, the first, the liquid crystal sealed between the second substrate, the first,
It has a pair of polarizing plates arranged outside the second substrate, and a reflector arranged outside either one of the polarizing plates.

According to the above configuration, the color filter plays the role of a lens, and collects obliquely incident light in the normal direction of the panel to prevent color mixing between adjacent pixels.
This has the effect that a reflective liquid crystal display device with high color purity can be realized even when viewed obliquely.

According to a seventh aspect of the present invention, there is provided a reflection type liquid crystal display device, wherein the first substrate comprising the color filter substrate according to any one of the first to fifth aspects is disposed to face the first substrate. A second substrate having a reflective driving electrode, a liquid crystal sealed between the first and second substrates, and a polarizing plate disposed outside the first substrate.

According to the above configuration, the color filter plays the role of a lens, and collects obliquely incident light in the normal direction of the panel to prevent color mixing between adjacent pixels.
In addition to high color purity even when viewed obliquely, there is an effect that a reflective liquid crystal display device in which an image does not appear double can be realized.

[0022]

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

Embodiment 1 FIG. 1 is a view for explaining a first embodiment of a reflection type liquid crystal display device of a simple matrix system using a color filter substrate according to the present invention.

FIG. 1A is a plan view of the structure, and FIG. 1B is a sectional view taken along the line aa ′. On a color filter substrate (common substrate) 100, R (red), G (green), and B (blue) color filters 102, 103, and 104, and on a strip-shaped transparent electrode 106 via a protective film 105. Is the alignment film 1
07 is formed. On the other hand, on the segment substrate 110, the segment electrodes 112 are arranged in a strip shape, and the alignment film 1 is formed.
17 are formed. Liquid crystal 130 is sealed between the two substrates with a specific gap therebetween. A polarizing plate 108 is attached to one common substrate 100, and a polarizing plate 118 and a reflecting plate 119 are attached to the other segment substrate 110 in accordance with the designated transmission and absorption axes, respectively. Is displayed by controlling the amount of reflected light by the electric field between the electrodes applied to the liquid crystal.

Here, on the common substrate 100, there is no light-shielding film (black matrix) used in the transmission type liquid crystal display device between the respective color filters. Red), G (green),
The B (blue) layer is a color filter having a convex lens structure in which the film thickness at the center of the pixel is large. In this embodiment, the thickness of the protective film 105 is desirably formed at least so as to be able to absorb the unevenness of the color filter and flatten it. By flattening with this protective film, the orientation can be stabilized, and the image quality of the entire screen can be made uniform.

FIG. 3 is a perspective view showing the color filter substrate 100 in detail. (A) shows a case of a stripe arrangement, which is a ridge-type color filter having a thick central portion along the strip direction of the segment electrode 112. (B) shows a case of a mosaic arrangement, in which the central portion has a thick ridge-type structure along the strip direction of the segment electrode 112, and R (red), G (green), B
(Blue) is a color filter that is divided.

As shown in FIG. 1, the oblique incident light 14
Numeral 1 denotes a light (151) which passes through a G (green) filter having a lens structure, is refracted in the normal direction of the panel by a lens effect, is reflected by a reflector 119, passes through a G (green) filter having a lens structure again, and is emitted. Becomes Similarly, the incident light 142 also passes through the G (green) filter having the lens structure, passes through the G (green) filter having the lens structure again, and becomes the outgoing light 152. Therefore, color mixing unlike the related art is unlikely to occur.

Therefore, in a structure in which the driving electrodes are disposed on the color filter and the protective layer, the color filter plays the role of a lens, and condenses obliquely incident light in the normal direction of the panel to form an adjacent pixel. It is possible to prevent color mixing between them.

[Embodiment 2] FIG. 6 is a structural sectional view for explaining a second embodiment of a reflection type liquid crystal display device of a simple matrix system using a color filter according to the present invention. FIG.
Are represented by using the last two digits of the symbol in FIG. 1 in common.

Unlike FIG. 1, a strip-shaped transparent electrode 60 is provided on a color filter substrate (common substrate) 600.
6. Further, an alignment film 607 is formed on the R (red), G (green), and B (blue) color filters 602, 603, and 604, and the protective film 605. On the other hand, on the segment substrate 610, the segment electrodes 612 are arranged in a strip shape,
An alignment film 617 is formed. Liquid crystal 630 is sealed between the two substrates with a specific gap. Further, a polarizing plate 608 is attached to one common substrate 600, and a polarizing plate 618 and a reflecting plate 619 are attached to the other segment substrate 610 according to designated transmission / absorption axes, respectively. Is displayed by controlling the amount of reflected light by the electric field between the electrodes applied to the liquid crystal. However, unlike FIG. 1, there is a voltage drop between the electrodes of both substrates due to the presence of the color filters 602, 603, 604 and the protective film 605, and the thickness of the color filter and the protective film cannot be set too large. . However, the thickness of the protective film is desirably at least enough to absorb the unevenness of the color filter and flatten it. By planarizing with a protective film, the orientation can be stabilized,
The image quality of the entire screen can be made uniform.

Here, on the common substrate 600, there is no light-shielding film (black matrix) used in the transmission type liquid crystal display device between the respective color filters, and the R-shaped electrode between the strip-shaped common electrode 606 and the protective film 605 is provided. (Red), G
The (green) and B (blue) layers are color filters having a convex lens structure in which the film thickness at the center of the pixel is large.

As shown in FIG. 6, the incident light 64 obliquely
Reference numeral 1 denotes a light 651 after passing through a G (green) filter having a lens structure, being refracted in the normal direction of the panel by a lens action, reflected by a reflector 619, and again passing through a G (green) filter having a lens structure. Becomes Similarly, the incident light 642 also passes through the G (green) filter having the lens structure, and then passes through the G (green) filter having the lens structure again to become the outgoing light 652. Therefore, color mixing unlike the related art hardly occurs.

Accordingly, in a structure in which the driving electrodes are disposed below the color filter and the protective layer, the color filter plays the role of a lens, and condenses obliquely incident light in the normal direction of the panel so that adjacent pixels can be formed. It is possible to prevent color mixing between them.

Embodiment 3 FIG. 4 is a view for explaining a third embodiment of a reflection type liquid crystal display device of a simple matrix system using a color filter substrate according to the present invention.

FIG. 4A is a plan view of the structure, and FIG. 4B is a sectional view taken along a line aa ′. 4 are represented by using the last two digits of the symbol in FIG. 1 in common. Unlike FIG. 1, the R (red), G (green), and B (blue) layers below the strip-shaped common electrode 406 and the protective film 405 are formed such that the pixel central portion is formed flat (flat region 402 ′). ), A color filter having a structure having a curvature that becomes thinner toward the pattern end of the segment electrode 412. Also in the present embodiment, the thickness of the protective film is desirably formed at least to such an extent that the unevenness due to the color filter can be absorbed and flattened. By flattening with the protective film, the orientation can be stabilized, and the image quality of the entire screen can be made uniform.

As shown in FIG. 4, the oblique incident light 44
Numeral 1 denotes a light 451 after passing through a G (green) filter having a lens structure, being refracted in the normal direction of the panel by a lens action and reflected by a reflector 419, and then passing through a G (green) filter having a lens structure again. Becomes Similarly, the incident light 442 also passes through the G (green) filter having the lens structure and then passes through the G (green) filter having the lens structure again to become the outgoing light 452. Further, in the flat region 402 ′, since the incident light transmitted through this region is far from the adjacent pixels, it does not become the reflected light transmitted through the adjacent pixels, so that color mixing hardly occurs.

Accordingly, similarly to the first embodiment, the portion having the curvature at the end of the color filter functions as a lens,
Light entering obliquely is condensed in the normal direction of the panel, so that color mixing between adjacent pixels can be prevented.

FIG. 5 is a perspective view showing the color filter substrate 400 in detail.

FIG. 5A shows a case of a stripe arrangement, which is a color filter having a ridge-type structure having a thick central portion along the strip direction of the segment electrode 412 and having a flat region 402 '. 3B shows a case of a mosaic arrangement. Unlike FIG. 3B, the central regions are thicker in the strip direction of the segment electrode 412 and the strip direction of the common electrode 406, and the flat regions 402 ″, 403 ″, 40
R (red), G (green), B (blue) of a mountain structure having 4 "
It is a color filter.

Here, in the structure shown in FIG. 6 in which the drive electrode is provided below the color filter and the protective layer,
Color filters 602, 603, 6 having a convex lens structure
Instead of using the color filter of the present embodiment, a color filter having a curvature such that the central portion of the pixel is formed flat and becomes thinner as it approaches the pattern edge,
Since the color filter portion can be formed thinner than the convex lens structure, a drop in driving voltage due to the thickness of the color filter can be reduced.

[Embodiment 4] FIG. 7 shows a fourth embodiment of a reflection type liquid crystal display device of a simple matrix type in which a color filter substrate is used and a reflection plate is arranged inside a panel substrate according to the present invention. FIG. 3 is a structural sectional view to be described. FIG.
Are represented by using the last two digits of the symbol in FIG. 1 in common.

Reference numeral 712 denotes a reflection plate made of thin-film aluminum, which can realize a high color purity and bright display because the number of polarizing plates is one less than in FIGS. 1, 4 and 6. Also,
By incorporating a reflector on the panel display surface, there is the advantage that the image does not look double.

Also in this embodiment, the oblique incident light 7
Reference numeral 41 denotes a reflection plate 712 after passing through a G (green) filter having a lens structure, and is refracted in a panel normal direction by a lens action.
After being reflected by, the light again passes through a G (green) filter having a lens structure and becomes emitted light 751. Similarly, the incident light 742 is also
After passing through the G (green) filter having the lens structure, the light again passes through the G (green) filter having the lens structure, and becomes the outgoing light 752. Therefore, color mixing unlike the related art hardly occurs. Also in the present embodiment, the thickness of the protective film is desirably formed at least to such an extent that the unevenness due to the color filter can be absorbed and flattened. By flattening with the protective film, the orientation can be stabilized, and the image quality of the entire screen can be made uniform.

Next, a manufacturing method will be described by taking a color filter corresponding to FIG. 5B as an example.

First, as a color filter, a photosensitive organic film containing a dye or a pigment is formed on a substrate. Next, fine processing is performed by photolithography using a reticle mask. FIG. 8 shows only one pixel, in which the shaded portion (black portion) is a light-shielding portion and the remaining portion (white portion) is a transmissive portion. In the black and white pattern, (a) is a saw-like pattern, (b) is a frame-like pattern, and (c) is a frame-like pattern in which holes are arranged. .
In an actual reticle mask, the above patterns are arranged in a matrix. Usually, the photosensitive organic film is of a negative type, and a portion irradiated with light remains as a film, so that the peripheral portion of the pattern is thinner than the central portion. By firing the above pattern, a gentle surface can be formed as a whole. In the case of a staining method, the patterned organic film may be stained with a specified color. Thereafter, a protective film is applied, and the transparent conductive film is patterned after sputtering to form an electrode.

In the first to fourth embodiments, the reflection type liquid crystal display device of the simple matrix system has been described.
The present invention can be similarly applied to an active matrix type reflection type liquid crystal display device in which an element substrate on which a MIM (metal / oxide film / metal) or a TFT (thin film transistor) is formed in a matrix is arranged to face a color filter substrate.

Here, if the refractive index of the color filter is made higher than the refractive index of the protective film, the role of the lens of the color filter is further improved, and the light obliquely incident is condensed in the normal direction of the panel to be adjacent thereto. This has the effect that color mixing between pixels can be further improved.

The colors of the color filters are as follows.
The same applies when cyan, magenta, and yellow, which are complementary colors of R, G, and B, are used.

In particular, if R, G, and B are used as a transparent film without being dyed, a black-and-white reflective liquid crystal display device can of course be realized. In this case, improvement in contrast can be expected rather than color mixing between adjacent pixels.

Regarding the arrangement of the color filters, the same effect as in the mosaic arrangement can be naturally obtained in the case of the delta arrangement.

[0051]

According to the reflection type liquid crystal display device of the simple matrix type and the reflection type liquid crystal display device of the active matrix type using switching elements such as MIM and TFT, the color filter has a convex lens structure.
The color filter plays the role of a lens, condensing obliquely incident light in the normal direction of the panel, preventing color mixing between adjacent pixels, and realizing a reflective liquid crystal display device with high color purity even when viewed obliquely. It has the effect of being able to.

[Brief description of the drawings]

FIG. 1 is a structural plan view (a) of a reflection type liquid crystal display device of a simple matrix type using a color filter according to a first embodiment of the present invention, and a sectional view (b) of FIG.

FIG. 2A is a structural plan view of a conventional simple matrix type reflection type liquid crystal display device, and FIG.

FIG. 3 is a perspective view showing details of a color filter substrate according to the first embodiment of the present invention.

FIGS. 4A and 4B are a plan view of a structure of a reflection type liquid crystal display device of a simple matrix type using a color filter substrate according to a third embodiment of the present invention, and a cross-sectional view taken along line aa ′ of FIG.

FIG. 5 is a perspective view showing details of a color filter substrate according to a third embodiment of the present invention.

FIG. 6 is a structural sectional view of a simple matrix type reflection type liquid crystal display device using a color filter substrate according to a second embodiment of the present invention.

FIG. 7 is a structural sectional view of a reflection type liquid crystal display device with a built-in reflection plate of a simple matrix system showing a fourth embodiment of the present invention.

FIG. 8 is a diagram showing an example of one pixel of a reticle pattern for producing a color filter of the present invention.

[Explanation of symbols]

100, 200, 400, 600, 700 ... color filter substrate 102, 202, 402, 602, 702 ... R
(Red) color filters 103, 203, 403, 603, 703... G
(Green) color filters 104, 204, 404, 604, 704... B
(Blue) Color filter 105, 205, 405, 605, 705: Protective film 106, 206, 406, 606, 706: Strip transparent electrode 107, 117, 207, 217, 407, 417, 6
07, 617, 707, 717... Alignment film 108, 118, 208, 218, 408, 418, 6
08, 618, 708 ... Polarizing plate 119, 219, 419, 619 ... Reflector 110, 210, 410, 610, 710 ... Segment substrate 112, 212, 412, 612, 712 ... Segment electrode 130, 230, 430, 630, 730 ... liquid crystal

Claims (7)

[Claims] 1. A color filter substrate having a color filter disposed on a substrate and a protective film and a drive electrode provided thereon, wherein the cross section of the color filter has a convex lens shape. Color filter substrate. 2. A color filter substrate comprising a driving electrode disposed on a substrate and a color filter and a protective film formed thereon, wherein the color filter has a convex lens-shaped cross section. substrate. 3. The color filter according to claim 1, wherein the color filters are arranged in a mosaic or delta pattern on the substrate, and a cross-sectional shape of the color filter has a curvature at a part near an end thereof. The color filter substrate according to claim 2. 4. The color filter according to claim 1, wherein the color filters are arranged in stripes on the substrate, and a cross-sectional shape of the color filters has a curvature at a part near an end thereof. 2. The color filter substrate according to 2. 5. The color filter substrate according to claim 1, wherein a refractive index of said color filter is higher than a refractive index of said protective film. 6. A first substrate comprising the color filter substrate according to any one of claims 1 to 5, and a second substrate having a transparent driving electrode disposed opposite to the first substrate. A substrate, a liquid crystal sealed between the first and second substrates, a pair of polarizing plates disposed outside the first and second substrates, and disposed outside one of the polarizing plates. A reflective liquid crystal display device comprising: 7. A first substrate comprising the color filter substrate according to any one of claims 1 to 5, and a second substrate having a reflective driving electrode disposed opposite to said first substrate. A liquid crystal sealed between the first and second substrates; and a polarizing plate disposed outside the first substrate.