JP4361979B2 - Color filter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color filter, and more particularly to a color filter for a reflective liquid crystal display device.
[0002]
[Prior art]
In recent years, a color liquid crystal display device has attracted attention as a flat display, and the color liquid crystal display device is classified into a reflection type and a transmission type. For example, a reflective color liquid crystal display device has a reflective layer and a colored layer (usually three primary colors of red (R), green (G), and blue (B)) on a substrate (if necessary). A color filter having a black matrix and a flattening layer) and a transparent electrode layer, and a TFT array substrate having a thin film transistor (TFT element) and a pixel electrode on a transparent substrate facing each other with a predetermined gap therebetween. In addition, a liquid crystal layer is formed on the portion, and a phase difference plate, a polarizing plate, and the like are provided on the color filter (observer side).
[0003]
[Problems to be solved by the invention]
In the conventional reflective color liquid crystal display device as described above, most of the light that has entered the display screen at a small incident angle and passed through the liquid crystal layer and the colored pattern is reflected by the reflective layer and has the same color. It passes through the colored pattern and the liquid crystal layer and is emitted from the display screen and recognized by the observer. However, some of the light that is obliquely incident on the display screen and passes through the liquid crystal layer and the colored pattern and is reflected by the reflective layer is absorbed by the colored pattern of other colors. For this reason, there is a limit to the light utilization efficiency, which hinders the brightness and directivity of the display image.
[0004]
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a color filter that enables a reflective color liquid crystal display device having high brightness and excellent color characteristics.
[0005]
[Means for Solving the Problems]
In order to achieve such an object, the present invention comprises a substrate, a reflective layer sequentially laminated on the substrate, a colored layer comprising a plurality of colored patterns, and a common transparent electrode layer, and the reflective layer is colored. The surface on the layer side was configured to have a concave shape for each colored pattern.
[0006]
Further, the present invention includes a substrate, a driving element layer sequentially laminated on the substrate, a reflective electrode layer, and a colored layer composed of a plurality of colored patterns, and the colored layer of each reflective electrode constituting the reflective electrode layer It was set as the structure where the surface of the side was concave shape.
[0007]
In the present invention as described above, light that passes through the colored pattern of the colored layer through various angles and enters the reflective layer or the reflective electrode layer is allowed to pass through the same colored pattern in the concave reflective layer or reflective electrode layer. To reflect.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the best embodiment of the present invention will be described.
[0009]
FIG. 1 is a schematic longitudinal sectional view showing an embodiment of the color filter of the present invention. In FIG. 1, the color filter 1 includes a substrate 2, a reflective layer 3, a colored layer 5, and a common transparent electrode layer 6 sequentially laminated on the substrate 2, and the colored layer 5 includes a red colored pattern 5 </ b> R and a green color. It consists of a colored pattern 5G and a blue colored pattern 5B.
[0010]
As the substrate 2 constituting the color filter 1, various glass substrates, metal substrates, resin substrates, composite substrates made of these two or more materials, and the like can be used. For example, it can be set to about 0.3 to 10 mm.
[0011]
The reflective layer 3 constituting the color filter 1 has a concave surface 3a on the colored layer 5 side for each colored pattern (5R, 5G, 5B). FIG. 2 is a schematic longitudinal sectional view for explaining the sectional shape of the reflective layer 3 taken along the line AA of the color filter 1 shown in FIG. As shown in FIGS. 1 and 2, in the color filter 1, the concave shape of the surface 3a of the reflective layer 3 is configured in both vertical and horizontal directions. That is, in the region corresponding to each coloring pattern of the reflective layer 3, a concave shape is formed by a curved surface that gradually becomes deeper from the periphery toward the center. There is no restriction | limiting in particular in such a concave shape, The curvature of said curved surface can be set suitably, and the concave-shaped surface may consist of a set of several small area planes.
[0012]
Such a reflective layer 3 is formed on a resin pattern formed by transferring a resin such as an acrylic resin onto the substrate 2 using a mold processed by a method such as electron beam drawing, or on the substrate 2. A thin metal film such as aluminum is formed by a known film deposition method such as vapor deposition or sputtering on a resin pattern having a concave shape obtained by applying resin and exposing and developing using a mask with a micropattern. Can be created.
[0013]
The colored layer 5 can be formed by a known pigment dispersion method, dyeing method, electrodeposition method or the like, and each colored pattern (5R, 5G, 5B) is also a stripe type, mosaic type, triangle type, four pixels. There are no particular restrictions on the arrangement type.
[0014]
Further, the common transparent electrode layer 6 constituting the color filter 1 is made of indium tin oxide (ITO), zinc oxide (ZnO), tin oxide (SnO), etc., and alloys thereof, sputtering method, vacuum deposition method, etc. The film can be formed by a general film forming method such as a CVD method. The common transparent electrode layer 6 has a thickness of about 0.01 to 1 μm, preferably about 0.03 to 0.5 μm.
[0015]
In the above-described embodiment, the concave shape formed for each colored pattern (5R, 5G, 5B) on the surface 3a on the colored layer 5 side of the reflective layer 3 is composed of one concave portion. May be composed of two or more recesses. FIG. 3 is a schematic longitudinal sectional view showing such a color filter of the present invention, and FIG. 4 is a schematic longitudinal sectional view for explaining the sectional shape of the reflective layer at the line BB of the color filter shown in FIG. FIG. 3 and 4, the color filter 1 ′ includes a substrate 2, a reflective layer 3 ′ sequentially laminated on the substrate 2, a colored layer 5, and a common transparent electrode layer 6. The colored layer 5 is red. It is composed of a coloring pattern 5R, a green coloring pattern 5G, and a blue coloring pattern 5B. The reflective layer 3 ′ has a concave surface 3′a on the colored layer 5 side for each colored pattern (5R, 5G, 5B), and the concave shape corresponding to one colored pattern is 4 It is composed of two recesses. The four concave portions constituting one concave shape are each formed by a curved surface that gradually becomes deeper from the periphery toward the center.
[0016]
In such a color filter 1, 1 ′, light that has entered the reflective layer 3 through the colored pattern of the colored layer 5 at various angles is reflected by the reflective layer 3 so as to pass through the same colored pattern. For example, as illustrated in FIG. 1, the light a that has entered the color filter 1 at a small incident angle and passed through the colored pattern 5R is reflected by the reflective layer 3 and passes through the same colored pattern 5R to be emitted. Recognized by the observer. Further, the light b that has entered the color filter 1 at a large incident angle and has passed through the colored pattern 5R is reflected by the concave reflective layer 3 and emitted through the same colored pattern 5R (shown by a solid line). Recognized by the person. Therefore, the reflective color liquid crystal display device using the color filter of the present invention has high light utilization efficiency and excellent brightness and directivity. On the other hand, in the conventional color filter, the incident light b as described above becomes reflected light as indicated by a broken line, and thus is absorbed by the colored pattern of other colors, and the light use efficiency is low.
[0017]
FIG. 5 is a schematic longitudinal sectional view showing another embodiment of the color filter of the present invention. In FIG. 5, the color filter 11 includes a substrate 12, a drive element layer 13, a reflective electrode layer 14, and a colored layer 15 that are sequentially stacked on the substrate 12, and the colored layer 15 includes a red colored pattern 15 </ b> R and a green colored color. It consists of a pattern 15G and a blue coloring pattern 15B.
[0018]
The drive element layer 13 constituting the color filter 11 includes a thin film transistor (TFT) formed in a predetermined pattern and drain, source, and gate electrodes.
[0019]
The reflective electrode layer 14 is a pixel electrode connected to the drain electrode, and is formed on the drive element layer 13 via an insulating layer made of acrylic resin or the like, and a colored layer of each reflective electrode constituting the reflective electrode layer 14. The surface 14a on the 15th side has a concave shape formed by a curved surface that gradually becomes deeper from the periphery toward the center. There is no restriction | limiting in particular in such a concave shape, The curvature of said curved surface can be set suitably, and the concave-shaped surface may consist of a set of several small area planes.
[0020]
For example, such a reflective electrode layer 14 is filled with a resin such as an acrylic resin in a mold processed by a method such as electron beam drawing on the driving element layer 13, and the concave shape is formed by transferring this resin. A resin pattern having a concave shape is formed by applying a photosensitive resin and exposing / developing through a fine pattern mask, and applying aluminum, chromium, gold on the resin pattern. A metal thin film such as silver or copper is formed by a known film forming means such as a vapor deposition method or a sputtering method, and is subjected to mirror finish. The thickness of the metal thin film can be set in the range of 500 to 10,000 mm, preferably 1000 to 3000 mm.
[0021]
In addition, the board | substrate 12 and the colored layer 15 which comprise the color filter 11 are the same as the board | substrate 2 and the colored layer 5 in the above-mentioned color filter 1, and description here is abbreviate | omitted.
[0022]
In the present invention, as shown in FIG. 6, the color layer 11 ′ may be a color filter 11 ′ having a surface shape corresponding to the concave shape of the reflective electrode layer 14. Similarly to the color filter 1 ′, the concave shape of the surface 14 a on the colored layer 15 side of the reflective electrode constituting the reflective electrode layer 14 may be composed of two or more concave portions.
[0023]
Similarly to the color filter 1 described above, such color filters 11 and 11 ′ pass through the colored patterns of the colored layers 15 and 15 ′ at various angles and enter the reflective electrode layer 14. Since it is reflected by the reflective electrode layer 14 so as to pass through, the reflective color liquid crystal display device using this color filter has high light utilization efficiency and excellent brightness and directivity. .
[0024]
In addition, the color filter of this invention may be provided with the black matrix located between each coloring pattern which comprises the colored layers 5, 15, 15 '. In this case, the black matrix can be formed of a light shielding resin, a metal such as chromium.
[0025]
Next, an example of a reflective color liquid crystal display device using the color filter of the present invention will be given.
[0026]
FIG. 7 is a schematic longitudinal sectional view showing a reflective color liquid crystal display device using the color filter 1 of the present invention shown in FIG. In FIG. 7, the reflective color liquid crystal display device 21 includes a driving element layer 33 having a pixel electrode on one surface of a transparent substrate 32 and a counter electrode substrate 31 having a retardation plate 34 and a polarizing plate 35 on the other surface. And the common transparent electrode layer 6 of the color filter 1 of the present invention face each other through a predetermined gap, and a liquid crystal layer 22 is formed in the gap portion.
[0027]
FIG. 8 is a schematic longitudinal sectional view showing a reflective color liquid crystal display device using the color filter 11 of the present invention shown in FIG. In FIG. 8, a reflective color liquid crystal display device 41 includes a counter electrode substrate 51 having a common transparent electrode layer 53 on one surface of a transparent substrate 52 and a retardation plate 54 and a polarizing plate 55 on the other surface, The color layer 15 of the color filter 11 of the present invention is opposed to each other through a predetermined gap, and a liquid crystal layer 42 is formed in a gap portion.
[0028]
【Example】
Next, an Example is shown and this invention is demonstrated further in detail.
Example 1
As the substrate, a 0.7 mm thick glass substrate (Corning 7059 glass) was prepared. On this glass substrate, an acrylic resin is transferred and cured using a mold processed by an electron beam drawing method to form a resin layer, and then an aluminum thin film (thickness 1000 mm) is formed on this resin layer by sputtering. A reflective layer was formed by coating. This reflective layer has a concave shape for each region of 300 × 100 μm, and each concave shape is a curved surface that gradually becomes deeper from the periphery toward the center in the direction parallel to the short side, and the maximum depth is The surface is about 1 μm.
[0029]
Next, a photosensitive coloring material for a red coloring pattern is applied onto the reflective layer by a spin coating method, the coating film is exposed through a predetermined photomask, and then developed using a developer, and a glass substrate is formed. The colored layer was cured by holding at 80 ° C. for 3 minutes to form a red colored pattern.
[0030]
Similarly, using the photosensitive coloring material for the green coloring pattern and the photosensitive coloring material for the blue coloring pattern, a green coloring pattern and a blue coloring pattern were formed in the same manner as described above to obtain a colored layer. In this colored layer formation, each colored pattern was formed corresponding to each concave shape of the reflective layer.
[0031]
Next, a transparent electrode (ITO) layer is formed on the colored layer according to a conventional method, and an alignment film of polyimide resin (thickness 900 μm) is formed on the transparent electrode layer, and the structure as shown in FIG. A color filter (Example 1) was obtained.
[0032]
Then, a TFT drive element layer and a polyimide resin alignment film (thickness 900 μm) are formed on one surface of a 0.7 mm thick glass substrate (Corning 7059 glass), and a retardation plate is formed on the other surface of the glass substrate. A polarizing plate is laminated to form a counter electrode substrate, the counter electrode substrate is opposed to the alignment film of the color filter (Example 1) produced as described above, and a nematic liquid crystal layer (thickness 6.0 μm) is provided to provide a reflective type. A color liquid crystal display device was produced.
(Example 2)
As the substrate, a 0.7 mm thick glass substrate (Corning 7059 glass) was prepared, and a TFT driving element layer, a resin pattern, and a reflective electrode layer made of aluminum were formed on the glass substrate. The reflective electrode layer is formed by transferring and curing an acrylic resin filled in a mold processed by an electron beam drawing method on the TFT driving element layer to form a resin pattern having a concave shape. Sputtering is performed on the acrylic resin layer. An aluminum thin film (thickness 1000 mm) was formed by the method. This reflective electrode layer has a concave shape for each region of 300 × 100 μm, and each concave shape is a curved surface that gradually becomes deeper from the periphery toward the center in the direction parallel to the short side, and has a maximum depth. Is formed of a surface having a thickness of about 1 μm.
[0033]
Next, a photosensitive coloring material for a red coloring pattern is applied on the reflective electrode layer by a spin coating method, the coating film is exposed through a predetermined photomask, and then developed using a developer, and a glass substrate. Was kept at 80 ° C. for 3 minutes to cure the colored layer to form a red colored pattern.
[0034]
Similarly, using the photosensitive coloring material for the green coloring pattern and the photosensitive coloring material for the blue coloring pattern, a green coloring pattern and a blue coloring pattern were formed in the same manner as described above to obtain a colored layer. In this colored layer formation, each colored pattern was formed corresponding to each concave shape of the reflective electrode layer.
[0035]
Next, an alignment film (thickness: 900 μm) of polyimide resin was formed on the colored layer to obtain a color filter (Example 2) having a structure as shown in FIG.
[0036]
Then, a common transparent electrode (ITO) layer is formed on one surface of a 0.7 mm thick glass substrate (Corning 7059 glass), and a polyimide resin alignment film (thickness 900 μm) is formed. A counter plate was formed by laminating a retardation plate and a polarizing plate on the surface. The counter substrate and the alignment film of the color filter (Example 2) produced as described above were made to face each other, and a nematic liquid crystal layer (thickness 6.0 μm) was provided to produce a reflective color liquid crystal display device.
(Comparative example)
A color filter (comparative example) was produced in the same manner as in Example 1 except that an aluminum thin film (thickness: 1000 mm) was formed on a glass substrate by sputtering to form a flat reflective layer, and this color filter was used. Thus, a reflective color liquid crystal display device was produced.
[0037]
Next, the display images of the reflection type color liquid crystal display devices using the color filter of the present invention (Example 1) and the comparative color filter (Comparative Example) were evaluated. That is, among the display images R, G, and B, as a result of comparing the reflectance in the front direction when displaying one color, the reflectance of Example 1 is improved by about 8% compared to the comparative example, and the image quality is excellent. Met.
[0038]
【The invention's effect】
As described above in detail, according to the present invention, since the surface of the reflective layer or the reflective electrode layer on the colored layer side is concave, the reflective layer or the reflective electrode layer passes through the colored pattern of the colored layer at various angles. Is reflected by the reflective layer or the reflective electrode layer so as to pass through the same colored pattern. Therefore, the reflective color liquid crystal display device using the color filter of the present invention has a light utilization efficiency, The directivity is improved, and the display image has high brightness and excellent color characteristics.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing an embodiment of a color filter of the present invention.
FIG. 2 is a schematic longitudinal sectional view taken along line AA of the color filter shown in FIG.
FIG. 3 is a schematic longitudinal sectional view showing another embodiment of the color filter of the present invention.
4 is a schematic longitudinal sectional view taken along line BB of the color filter shown in FIG.
FIG. 5 is a schematic longitudinal sectional view showing another embodiment of the color filter of the present invention.
FIG. 6 is a schematic longitudinal sectional view showing another embodiment of the color filter of the present invention.
FIG. 7 is a schematic longitudinal sectional view showing an example of a reflective color liquid crystal display device using the color filter of the present invention.
FIG. 8 is a schematic longitudinal sectional view showing another example of a reflective color liquid crystal display device using the color filter of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,1 '... Color filter 2 ... Substrate 3, 3' ... Reflective layer 5 ... Colored layer 6 ... Common transparent electrode layer 11, 11 '... Color filter 12 ... Substrate 13 ... Drive element layer 14 ... Reflective electrode layer 15, 15 '... Colored layers 21, 41 ... Reflective color liquid crystal display device

Claims (2)

A substrate, a reflective layer sequentially laminated on the substrate, a colored layer composed of a plurality of colored patterns, and a common transparent electrode layer, and the colored layer side surface of the reflective layer has a concave shape for each colored pattern A color filter characterized by that. A substrate, a driving element layer sequentially laminated on the substrate, a reflective electrode layer, and a colored layer composed of a plurality of colored patterns, and the surface on the colored layer side of each reflective electrode constituting the reflective electrode layer is concave The color filter characterized by being.

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