JPH11337716A - Reflective color filter, method of manufacturing the same, and liquid crystal display - Google Patents

Abstract

(57) Abstract: A reflective color filter using a UV-curable cholesteric liquid crystal or the like, which has a sufficient resolution, good reflectance, and a vertical sectional shape, a method of manufacturing the same, and a liquid crystal display. Provide equipment. A pattern-shaped concave portion is provided on a substrate, a light-absorbing layer is provided on the entire surface of the substrate, and a UV-curable cholesteric liquid crystal layer is provided in the patterned concave portion. A pattern-shaped concave portion 4 is provided on a substrate 1, a light absorbing layer 5 is provided, a UV-curable cholesteric liquid crystal is oriented and filled, a reflective layer 10 is provided, a film 6 is provided, the substrate is heated, and a reflection wavelength of the reflective layer is provided. And exposing the pattern, fixing the reflection wavelength, and forming a pattern of the reflection layer. A liquid crystal display device using the reflective color filter.

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 filter used in a reflection type liquid crystal display device and the like, and more particularly to a reflection type color filter having a high reflectance, a method of manufacturing the same, and a liquid crystal display device.

[0002]

2. Description of the Related Art As a reflection type color filter used in a reflection type liquid crystal display device or the like, a method of providing a wavelength and polarization selective reflection layer, for example, a method of providing a reflection layer using a UV curable cholesteric liquid crystal or the like is known. Proposed. This method utilizes the fact that a high reflectance can be obtained by aligning the orientation of molecules such as UV-curable cholesteric liquid crystal. The wavelength of the reflected light can be selected by controlling the temperature of the liquid crystal. For this reason, even in the case of a single layer of a UV-curable cholesteric liquid crystal or the like, by forming a pattern by controlling the temperature at each wavelength, a reflection color pattern of a plurality of colors with each wavelength fixed is formed. It is possible to do.

As a method proposed so far, for example, in order to align the orientation of liquid crystal, a UV-curable cholesteric liquid crystal or the like is sandwiched between two glass substrates, pressure is applied while heating, and the whole is made uniform. There is a method of aligning and subsequently exposing the pattern while heating to a temperature that reflects the required wavelength to obtain a reflective layer pattern of the required wavelength. However, such a method has a problem that a gap corresponding to the thickness of the glass substrate at the time of exposure is large and a pattern having a sufficient resolution cannot be obtained.

[0004] As another method, for example, a photosensitive black resist is applied on a substrate, and a light absorbing layer is formed in a predetermined pattern-shaped concave portion by a photolithography method.
There is a method of embedding a UV-curable cholesteric liquid crystal or the like in a pattern-shaped concave portion and then exposing the pattern while heating to a temperature that reflects a required wavelength to obtain a reflective layer pattern of a required wavelength. However, in such a method, the film thickness accuracy and flatness accuracy of the concave portion are poor, for example,
The surface roughness (Ra) of the bottom surface of the concave portion is about 200 to 300 mm.
Therefore, there is a problem that the alignment direction of the UV-curable cholesteric liquid crystal or the like embedded in the concave portion is not uniform, and it is not possible to obtain a good reflectance. Further, there is a problem that the cross-sectional shape of the wall surface of the pattern-shaped concave portion cannot be made vertical.

[0005]

SUMMARY OF THE INVENTION The present invention provides a reflective color filter using a wavelength- and polarization-selective reflective layer, such as a reflective color filter using a UV-curable cholesteric liquid crystal. A reflective color filter is obtained in which a patterned pattern is obtained, the orientation direction is uniform, good reflectance is obtained, and the cross-sectional shape of the wall surface of the pattern-shaped concave portion is vertical, and the method for producing the same and the reflective color filter are used. A liquid crystal display device.

[0006]

Means for Solving the Problems The present invention provides at least:
On the substrate, a patterned concave portion, a light absorbing layer on the substrate and on the bottom of the patterned concave portion, and a wavelength and polarization selective reflection layer on the light absorbing layer on the bottom of the patterned concave portion are provided. Is a reflection type color filter. Further, the present invention is the reflective color filter according to the above invention, wherein the wavelength and polarization selective reflection layer is a UV-curable cholesteric liquid crystal or a chiral nematic liquid crystal.

Further, the present invention provides (1) a step of providing a pattern-shaped concave portion on a substrate, (2) a step of providing a light-absorbing layer on the entire surface of the substrate provided with the patterned concave portion, and (3) a step of forming the light-absorbing layer. A step of applying a UV curable cholesteric liquid crystal or a chiral nematic liquid crystal to the patterned concave portion provided with the absorbing layer while applying pressure to orient the liquid crystal to form a reflective layer, and bonding a film; and (4) providing the reflective layer. Heating the substrate with the film attached thereto, controlling the temperature, selecting the reflection wavelength of the reflection layer, exposing the pattern, and forming a pattern of the reflection layer having a fixed reflection wavelength; This is a method of manufacturing a reflection type color filter including a step of repeating the step (4) for each required color.

Further, the present invention is a liquid crystal display device using the reflection type color filter of the above invention.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a reflective color filter and a method for manufacturing the same according to the present invention will be described in detail with reference to the embodiments. FIG. 1 is an explanatory diagram showing a cross section of an embodiment of the reflection type color filter according to the present invention. In FIG. 1, a patterned recess (4) is formed on a substrate (1), and a patterned recess (4) is formed on the bottom of the patterned recess (4) and on the substrate (1). A light absorbing layer (5) is provided on a portion that is not provided, that is, on the entire surface of the substrate (1). In addition, a pattern-shaped recess (4)
A blue, green, and red reflective layer (10B, 10G, 10R) is provided on the light absorbing layer (5) on the bottom of the light absorbing layer (5B). ) Functions as a reflective color filter.

FIG. 2 is an explanatory view showing a cross section of the function of the reflection type color filter according to the present invention. In FIG.
When the incident light (I _i ) from the outside enters the reflective layer (10), a part of the light is emitted to the outside as reflected light (R _e ) whose wavelength (color) is selected, and a part is The light is transmitted through the reflective layer (10) as transmitted light (T _r ), and is absorbed by the light absorbing layer (5) on the bottom of the pattern-shaped concave portion (4). The light absorbing layer (5) provided on the portion of the substrate (1) where the pattern-shaped concave portion (4) is not formed has a function of a black matrix of a reflective color filter as a light shielding layer. is there.

The reflection layer (10) is a wavelength- and polarization-selective reflection layer. The wavelength- and polarization-selective reflection layer is, for example, a cholesteric liquid crystal in which incident light is divided into right-handed light and left-handed light. The light is divided into circularly polarized light, one of which is scattered and reflected and the other is transmitted, and has a property that the wavelength (color) of the scattered reflected light greatly changes with temperature.

As the light absorbing layer in the present invention, for example, a black resin composition or a black metal (CrO ₂ ) is used. As the reflecting layer, for example, a UV-curable cholesteric liquid crystal or a chiral nematic liquid crystal is used. Is used.

FIGS. 3A to 3G are explanatory views showing the steps of manufacturing the reflection type color filter of the present invention. As shown in FIG. 3A, the substrate (1) is not particularly limited as long as it is used for a display device or the like.
A glass substrate such as alkali-free glass and soda glass can be used.

The pattern-shaped concave portions on the substrate (1) can be formed by, for example, an etching method. The photoresist is used as an etching resist, and the photoresist may be either a negative type or a positive type as long as the material is resistant to an etchant. Specifically, a rubber-based photoresist, for example, OMR-85 (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is preferable. A pattern is exposed and developed on this photoresist layer to obtain an etching resist pattern.

Subsequently, etching is performed using a glass etching ink to form a pattern-shaped concave portion (4) as shown in FIG. The glass etching ink is a mixture of a fluoride such as calcium fluoride and aluminum fluoride soda and an acid such as hydrochloric acid and sulfuric acid. When etching, the substrate (1) and the glass etching ink may be heated. Etching depth is 10-20
About μm is preferable. After the etching, the glass etching ink is washed with water and then flown, and the etching resist is stripped and removed with a stripping solution.

Next, a light absorbing layer (5) is provided on the substrate (1) on which the pattern-shaped concave portions (4) are formed. As shown in FIG. 3C, the light absorbing layer (5) is formed by applying a black resin composition,
Alternatively, a black metal (CrO ₂ ) is provided on the entire surface of the substrate by vapor deposition or the like. Subsequently, a UV-curable cholesteric liquid crystal or a chiral nematic liquid crystal is dropped while heating the substrate on which the light absorbing layer (5) is provided, and the pattern is formed by applying a shear using a roll press or a squeegee. It is embedded in the concave portion (4), and a film (6) or the like is bonded thereto, and as shown in FIG.
Is provided.

As a material for the roll or the like, a sufficiently flexible material such as urethane rubber or silicon rubber is used so as not to damage the light absorbing layer (5). By embedding with a roll press machine in this way, UV
The curable cholesteric liquid crystal or chiral nematic liquid crystal is given a share in the rotation direction of the roll, so that the orientation directions of the liquid crystal molecules are uniform and a good reflectance can be obtained. To further align the alignment direction, an alignment film is formed on the light absorbing layer (5) at the bottom of the pattern-shaped concave portion (4) before embedding the UV-curable cholesteric liquid crystal or chiral nematic liquid crystal. A rubbing process can be performed according to the rotation direction of the roll.

Subsequently, the reflection layer (10) is provided with reflection characteristics of a desired wavelength. As shown in FIG. 3E, the substrate on which the reflective layer (10) is provided and the film (6) and the like are bonded is heated (30) and subjected to UV exposure (20). At this time, the heating temperature depends on the type of UV-curable cholesteric liquid crystal or chiral nematic liquid crystal used,
It is determined by a desired wavelength. As a UV-curable cholesteric liquid crystal or chiral nematic liquid crystal, for example, in the case of product number TC3947L manufactured by WACKER, when the heating temperature is set to 95 ° C., 70 ° C., and 45 ° C., respectively, the reflection wavelengths are 465 nm, 545 nm, and 6 nm.
It changes to 20 nm. That is, for example, the substrate is set at 95 ° C.
And the reflected light centered on the wavelength of 465 nm is selected.

Then, while maintaining this temperature, a U-shaped photomask (8) having a desired pattern shape, for example, the pattern-shaped concave portion (4) is formed on the reflective layer (10).
V exposure (20) is performed. In the UV-exposed portion of the liquid crystal, the pitch of the liquid crystal is fixed by the polymerization reaction in the side chain of the cholesteric liquid crystal by the radical generated by the initiator, and the wavelength of the reflected light does not change even if the temperature is changed thereafter. The wavelength is fixed. Thus, FIG.
(E) A blue reflective layer (10B) having a reflection characteristic of reflecting light having a wavelength of 465 nm as a center, as shown in (f).
Is formed.

On the other hand, since the unexposed portion which has not been subjected to UV exposure has not undergone a polymerization reaction, there is a property that when the heating temperature is set to a different temperature, the reflected wavelength changes to a different one. That is, by setting a different temperature for each desired color and repeating the above steps for each desired color, a reflection type color filter can be obtained as shown in FIG.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below.

Example 1 Alkali-free glass (product number 7059) manufactured by Corning Incorporated, size 100 mm × 100 m
m, 0.7 mm thick substrate on a substrate of Tokyo Ohka Kogyo Co., Ltd.
Manufactured by OMR-83 under the trade name of 1000r. p. m for 10 seconds, and dried at 100 ° C. for 30 minutes to obtain a photoresist layer having a thickness of about 1 μm. Next, a line width of about 10
UV exposure of 30 mJ / cm ² was performed using a photomask having a stripe pattern with a pitch of about 100 μm.

After the UV exposure, the substrate was immersed in a 1% aqueous solution of tetramethylammonium hydroxide for 60 seconds and developed to obtain an etching resist pattern on the substrate. Subsequently, etching was performed using a glass etching ink. GLA made by DECA as glass etching ink
5 g of SSETCH was dropped, and 200 r. p. m for 30 seconds and etched at 50 ° C. for 20 minutes.
After the etching, the glass etching ink was washed with pure water, the etching resist pattern was removed with dimethyl sulfoxide, and a pattern-shaped concave portion was formed on the substrate. The depth of the obtained patterned concave portion was about 11 μm.
The surface roughness (Ra) of the bottom surface of the pattern-shaped concave portion was about 50 °.

Next, a light absorbing layer was provided on the substrate on which the pattern-shaped concave portions were formed. As the light absorbing layer, a photosensitive black resin composition was used. CK7000 manufactured by Fuji Film Ohrin Co., Ltd. was spin-coated and dried at 70 ° C. for 20 minutes to obtain a photosensitive black resin composition layer having a thickness of about 1 μm. This layer is exposed to UV light of 300 mJ / cm ² , immersed in a developer (product number CD) for 10 minutes, developed, washed with pure water, baked at 230 ° C. for 60 minutes, and light-absorbed on the entire surface of the substrate. A layer was formed.

This substrate is placed on a platen of a roll press machine for about 8 hours.
While heating to 0 ° C., a UV-curable cholesteric liquid crystal (cholesteric liquid crystal: manufactured by WACKER, part number TC3947L) is used as a material for a reflective layer in a stripe shape on one end of the substrate.
5.0 parts by weight, initiator: Irg907 0.2 parts by weight, solvent: toluene 5.0 parts by weight), 5 g
Drop it and bury it in the pattern concave part while applying pressure,
The films were laminated. By embedding with a roll press machine in this manner, the UV-curable cholesteric liquid crystal is given a share in the roll rotation direction and the liquid crystal molecules are aligned in the same direction.

Subsequently, the substrate was heated and held at 95 ° C., and a UV exposure of 100 mJ / cm ² was performed using a blue pattern photomask in a state where reflected light having a wavelength of 465 nm was selected. Similarly, the substrate was heated and held at 70 ° C., and reflected light having a wavelength of 545 nm as a center was selected.
A cm ² UV exposure was performed. Similarly, 45
The sample was heated to and maintained at a temperature of ° C., and a UV exposure of 100 mJ / cm ² was performed using a red pattern photomask in a state where reflected light having a wavelength of 620 nm as a center was selected. After the UV exposure, the film was peeled off to obtain a reflective color filter having a blue pattern, a green pattern, and a red pattern.

The line width of the black matrix of the obtained reflection type color filter is as fine as about 10 μm.
The reflectance is about 70% for each of blue, green and red, and about 75 for each.
%, About 80%, and the cross-sectional shape of the wall surface of the pattern-shaped concave portion was vertical. Further, the display quality of the liquid crystal display device manufactured using the reflection type color filter was good.

[0028]

According to the present invention, a pattern-shaped concave portion is formed on a substrate.
The light-absorbing layer is provided on the substrate and on the bottom of the pattern-shaped concave portion, and the wavelength and polarization-selective reflective layer is provided on the light-absorbing layer on the bottom of the patterned concave portion. A reflection type color filter having a high ratio and a vertical cross section of the wall surface of the pattern-shaped concave portion can be obtained. Further, the present invention provides a patterned concave portion on a substrate, a light absorbing layer is provided on the entire surface of the substrate provided with the patterned concave portion, a wavelength and polarization selective reflection layer is provided in the patterned concave portion, and a film is attached. It is a method of manufacturing a reflection type color filter, in which a substrate is heated, a temperature is controlled, a reflection wavelength of a reflection layer is selected, a pattern is exposed, and a pattern of a reflection layer having a fixed reflection wavelength is formed. It is possible to manufacture a reflection type color filter having a sufficient resolving power, a good reflectance, and a vertical cross section of the wall surface of the pattern-shaped concave portion.
Further, according to the present invention, by using the reflection type color filter of the above invention, a liquid crystal display device having a sufficient resolution and a good reflectance can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a cross section of an embodiment of a reflection type color filter according to the present invention.

FIG. 2 is an explanatory view showing a cross section of the function of the reflection type color filter according to the present invention.

FIGS. 3A to 3G are cross-sectional views illustrating one embodiment of a process for manufacturing a reflective color filter according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate 4 ... Pattern concave part 5 ... Light absorption layer 6 ... Film 8 ... Mask 10 ... Reflection layer 10B ... Blue reflection layer 10G ... Green reflection layer 10R ... Red reflection layer _Ii ... Incident light _Re ... Reflected light _Tr ... Transmitted light 20 ... UV irradiation 30 ... Heating

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Shinji Ito 1-5-1, Taito, Taito-ku, Tokyo Inside Toppan Printing Co., Ltd. (72) Inventor Mizunin Tani 1-15-1, Taito, Taito-ku, Tokyo Toppan Printing Co., Ltd.

Claims (4)

[Claims] At least a pattern-shaped concave portion is provided on a substrate.
A reflection type color filter, wherein a light absorbing layer is provided on the substrate and on the bottom of the pattern-shaped recess, and a wavelength and polarization selective reflection layer is provided on the light absorption layer on the bottom of the pattern-shaped recess. . 2. The reflection type color filter according to claim 1, wherein said wavelength and polarization selective reflection layer is a UV-curable cholesteric liquid crystal or a chiral nematic liquid crystal. And (3) providing a light-absorbing layer on the entire surface of the substrate provided with the patterned recess; and (3) providing the light-absorbing layer. UV on the patterned recesses
Curable cholesteric liquid crystal or chiral nematic liquid crystal is filled while applying pressure and aligned to form a reflective layer, and a film is bonded; (4) heating the substrate provided with the reflective layer and bonding the film, Controlling the temperature, selecting the reflection wavelength of the reflection layer, exposing the pattern, and forming a pattern of the reflection layer having a fixed reflection wavelength. (5) For each color requiring the above step (4) A method of manufacturing a reflection type color filter including a step of repeating. 4. A liquid crystal display device using the reflection type color filter according to claim 1.