JPS62229204A - Color filter - Google Patents

Abstract

PURPOSE:To provide a color filter which has excellent flatness and the heat resistance to withstand a heat sealing stage by providing plural colors of colored picture element on a substrate, and adhering a heat resistant transparent film on the substrate surface via a heat resistant transparent adhesive agent layer of the layer thickness to fill the steps between the colored picture elements. CONSTITUTION:Plural colors of the colored picture element 12 are provided on the substrate 11 and the heat resistant transparent film 14 is adhered via the heat resistant transparent adhesive agent layer 13 to the surface of the substrate 11 provided with the picture elements 12. The adhesive agent layer 13 and film 14 provide the function to prevent the generation of the rugged steps in the color filter by the heat during heat sealing. A polyeter, polyether ether, etc. which have flat and high transmittance in 380-780mm visible wavelength region and are less elongated, contracted and deformed even at the high temp. applied thereto are applicable to the film 14. The adhesive agent of a polyamide, polybenzoimidazole, polyimide or silicone having transparency and heat resistance of about 200 deg.C is applicable as the heat resistant adhesive agent.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color filter used in a multicolor electro-optic display device.

[Conventional technology]

Multicolor electro-optical display devices using liquid crystals are used in televisions, various displays for computer terminals, monitors for video cameras, in-vehicle displays, and the like.

An example of a multicolor electro-optical display device using liquid crystal will be explained with reference to FIG.
) (1) are arranged opposite to each other in parallel with the liquid crystal (5) interposed therebetween,
Moreover, each substrate +11 is provided with a transparent electrode (2) of a predetermined shape, and at least one side of the transparent electrode (2) is provided with a transparent electrode (2). Red (uniform,
Colored pixels (3) of green (G) and blue (Bl) are formed.

Furthermore, an alignment layer (4) for aligning the liquid crystal is provided. Further, the outer peripheral portion is sealed with a sealing resin to form a liquid crystal display cell.

By arranging polarizing plates (6) on both sides or one side of this liquid crystal display cell and irradiating it with light from a light source (7), a multicolor image can be displayed. Various types of liquid crystals, such as twisted, nemati, li, and guest host, can be used as the liquid crystal for the above-mentioned liquid crystal display cell.

Conventionally, in color filters for multicolor electro-optic display devices, photolithography, printing, vapor deposition,
Colored pixels are formed by a method such as electrodeposition, and an organic or inorganic material is applied onto the formed colored pixels for the purpose of increasing physical and chemical strength, improving optical properties, and improving surface smoothness. A protective film made of the following is provided by coating or vapor deposition.

[Problem that the invention seeks to solve]

However, the conventional liquid crystal display cell as described above has several drawbacks as described below.

(1) Poor leveling When a transparent organic substance is applied to colored pixels as shown in Figure 3, 1
In order to eliminate the unevenness of colored pixels, the layer of transparent organic material should be applied to a fairly thick layer (for example, 10 μm when coating with Nuricorn resin).
above). However, when the film is made thick like this, unevenness in thickness due to the presence of dust and the like becomes more noticeable.

Furthermore, in the case of a thick protective film, unevenness may occur due to the surface tension of the fish-retaining film itself. There are uneven spots caused by convection. In addition, when a transparent electrode is placed between a colored pixel and a color filter substrate as shown in Figure 3, the distance between the electrodes increases as the protective film becomes thicker.
The internal impedance between the electrodes also increases, making it impractical.

(1) Increase in driving voltage In high-density liquid crystal display cells used for applications such as televisions, either a simple matrix type or a method using thin film transistors is adopted, and a simple matrix type for color.

In the case of a square type, a transparent electrode is usually provided between the substrate and the colored pixels. Although it is possible to provide a transparent electrode on the protective film that covers the colored pixels, stress is generated between the transparent electrode and the protective film during the heating process during the manufacturing process of the liquid crystal display cell.
Disconnection of the transparent electrode often occurs at the uneven step portion.

Therefore, the position of the transparent electrode is limited between the substrate and the colored pixels. And between the opposing electrodes, there is a colored pixel layer other than the liquid crystal and a protective f! Due to the presence of a membrane layer.

The voltage between the electrodes is distributed to each. Therefore, the driving voltage becomes large.

(+111 Variation in threnhold voltage between each color When forming colored pixels, it is difficult to control the film thickness between each color with high precision, and because it contains dyes, pigments, etc., the dielectric constant between each color is different.

For this reason, the threshold voltage differs between each color, and even if an equal voltage is applied between the electrodes, the transmittance differs depending on one colored pixel, and a uniform display is not achieved. FIG. 4 shows the change in transmittance when a voltage is applied between the electrodes in a normally dark liquid crystal and a transparent electrode is located between the substrate and the colored pixel.

The larger the thickness of the colored pixel and the smaller the dielectric constant.

The threshold voltage increases. That is, due to the difference in film thickness and/or dielectric constant, the operating voltage differs between each color, and as a result, as shown in FIG. The transmittance of green (G) colored pixels is around 50%, and the transmittance differs between each color.
The display is not uniform.

Therefore, the problem to be solved by the present invention is to solve the above problems, to have excellent flatness and heat resistance that can withstand the heat sealing process, and to be heat sealable even when transparent electrodes are provided on the color filter. To provide a color filter that does not cause disconnection of transparent electrodes due to the occurrence of uneven step portions on the color filter due to the influence of heat.

[Means for solving problems]

As a result of research to solve the above-mentioned problems, the present inventor provided colored pixels of multiple colors on a substrate, and attached a layer of heat-resistant transparent adhesive to the substrate surface on which the colored pixels were provided, filling the steps between the colored pixels. By adhering a heat-resistant transparent film through the agent layer,
The inventors have found a way to achieve the intended purpose, and have completed the present invention based on this knowledge.

That is, in the color filter of the present invention, colored pixels of a plurality of colors are provided on a substrate, and a heat-resistant transparent adhesive layer is applied to the substrate surface on which the colored pixels are provided to fill in the steps between the colored pixels. A transparent film is attached.

Accordingly, in the present invention, polyether, polyether ether, etc., which have a flat and high transmittance in the visible wavelength range of 380 to 780 m as a heat-resistant transparent film, and which do not stretch or deform even when exposed to high temperatures, are used. Polyetheretherketone, polyethersulfone, polysulfone, polyimide, polyamide, polyesterimide, aromatic polyamide, polyarylate, polycarbonate, urethane resin, polyphenylene quinde, polybenzimidazole, etc. are interconnected, polybenzimidazole-based, A polyimide-based or silicone-based adhesive that is transparent and has heat resistance of about 200° C. can be used.

FIG. 1 shows a color filter of the present invention.

Colored pixels (12) of a plurality of colors are provided on a substrate I, and a heat-resistant transparent film I is adhered via a heat-resistant transparent adhesive layer 0 to the surface of the substrate 09 on which the colored pixels α2 are provided.

[For production]

The heat-resistant adhesive layer and the heat-resistant transparent film function to prevent uneven steps from forming on the color filter due to heat during side heat sealing.

〔Example〕

Example 1 To explain with reference to FIG. 2 (al to e), 2
00% x 200% soda lime float glass (IQ
A water-soluble photosensitive solution consisting of gelatin and ammonium dichromate was coated on top to a thickness of 0.8 μm, and then dried.

Next, a first mask (18
Vacuum seal the I! After exposure and then development with hot water,
It was dried to form a layer to be dyed.

Next, cyclized rubber photoresist O, which is a negative resist.
After spin-coating MR-31 (manufactured by Tokyo Ohka ■) to a thickness of 0.7μ and drying, a second mask (not shown) was vacuum-adhered to the coated surface of OMR-81 and exposed. Then, after development, it was dried to form a first resist dyeing layer Qυ, and the area other than the dyed layer to be dyed red was covered with this resist dyeing layer.

Afterwards, it is dyed with a red dye bath and red colored pixels (c)
was formed. After that, the resisting film r2 made of OMB-81
After removing the mosquito with trichlorethylene heated to 80°C, QMI'L-81 was applied again and dried, and then a third mask (not shown) was vacuum-adhered to the OMR-81 applied surface. The film was exposed to light and then developed to form a second resist layer (not shown), and the area other than the colored layer to be dyed green was covered with the resist layer. After that, it was dyed in a green dye bath to form green colored pixels, the resist film was removed again with trichlorethylene, OMR-81 was applied again, and it was dried. 4 mask (not shown) is exposed in vacuum contact, and then developed to form a third resisting layer (not shown) and dyed with a blue dye bath to form a blue colored image; Finally, the resist dyeing layer was removed to form a red colored image @, a green colored image (c), and a blue colored image (image) for the purpose of additive color mixing type color synthesis as shown in Figure 2 (e1). .

The dyeing baths for each color used are as follows.

Red dye bath Liquid temperature 60℃ Green dye bath Liquid temperature 60℃ Blue dye bath Liquid temperature 60℃ Measure the surface irregularities of colored pixels after dyeing using a surface roughness meter α-8T E
P 2Q Q (Tenkov Instrument
As a result of measurement by t company), irregularities of up to 1.5μ were observed.

Next, a polyether sulfone film (manufactured by Mitsubishi Kasei ■) with a thickness of 25 μm was prepared, and a 10 μm thick film of Nricon-based addition reaction type adhesive 5E1700 (manufactured by Renlicon) was applied to the substrate surface on which one colored pixel was provided. A polyether sulfone film was pressure-bonded to the surface coated with an addition reaction type adhesive using a roller equipped with a rubber blanket. At this time, the roller was rotated at a substantially constant speed and fed at a speed of approximately 1 cIR/sec.

The adhesive was cured at 150°C to obtain a color filter.

The surface unevenness of the obtained color filter is hardly noticeable.

Electrodes were provided on the color filter obtained as described above in the following manner to form an electrode substrate.

That is, a transparent conductive film was created by applying a 200 OA film of ITO using a low-temperature sprayer, and then a photoresist (Microposit Y) 1350 manufactured by Hoechst was spin-coated at 1500 rpm, dried at 90°C for 30 minutes, and then the desired electrode was formed. After alignment with a photomask having a pattern, exposure using a mercury lamp (1fX light intensity 50 mJ/cd), immersion development with a special developing solution, and washing with water were performed to form a photoresist layer.

This is a mixed acid containing hydrochloric acid, nitric acid, and water in a ratio of 1:1 (40
) for 3 minutes, the excess conductive film was removed, and the photoresist layer was further removed with a special stripping solution to obtain an electrode substrate.

Next, a liquid crystal display cell was manufactured using the prepared electrode substrate, and a display test of the liquid crystal display cell was performed, and it was possible to perform a display without unevenness between each color at an appropriate driving voltage.

Example 2 A 200×300 1% thick soda lime float glass plate (300
A printed red colored image was obtained using red ink and a rubber squeegee.

The red ink adhering to the illuminance screen was completely washed away, and the red colored image was heat cured at 150°C. A green colored image was similarly obtained by shifting one plate by one pixel with respect to the suction table of a silk screen printing machine and using green ink. A blue colored image was obtained in the same manner by shifting the plate by one pixel to obtain an additive color mixing type colored image for color synthesis.

The ink composition of each color is shown below.

Red ink Green ink Blue ink Electrodes were provided on the color filter obtained by K as described above to form an electrode substrate in the following manner.

That is, a transparent conductive film with a 2000A film was prepared using ITO by low-temperature sputtering, and then a photoresist (Microposit)-1350 manufactured by Hoechst was spin-coated at 1500 rpm, dried at 90°C for 30 minutes, and then the desired electrode It was aligned with a photomask having a pattern, exposed to light using a mercury lamp (exposure 1150 mJ/cII), developed by immersion in a special developer, and washed with water to form a photoresist layer. 1:1 mixed acid (40℃)
The electrode substrate was immersed for 3 minutes to remove the excess conductive film, and then the photoresist layer was removed using a special stripping solution.

Next, a liquid crystal display cell was manufactured using the prepared electrode substrate, and a display test of the liquid crystal display cell was performed, and it was possible to perform a display without unevenness between each color at an appropriate driving voltage.

〔Effect of the invention〕

As detailed above, the color filter of the present invention has excellent flatness, and this color filter can be used to construct an electro-optic display cell that displays uniformly between colors at an appropriate driving voltage. Not only is it durable, but it is also highly heat resistant, and has the advantage that even if the spacer portion of the cell is heated to high temperatures in the process of heat-sealing, its quality will not be impaired.

[Brief explanation of drawings]

Figure 1 is a sectional view of the color filter of the present invention, Figure 2 (
al to e) are schematic cross-sectional views showing the procedure for producing colored pixels, FIG. 3 is a schematic cross-sectional view of an example of a conventional multicolor electro-optical display device, and FIG. 4 is a graph of applied voltage versus transmittance. be. (11)......Substrate (L3...Colored pixel αj...Heat-resistant adhesive α4... Heat-resistant film patent applicant Dainippon Printing Co., Ltd. Agent Patent attorney Atsushi Ko Nishi Figure 1 11... Motoyasu 12... Airoga Higashi 13...H@-)nmi54tt1 14...・Resistance A city

Claims (1)

[Claims] Colored pixels of a plurality of colors are provided on a substrate, and a heat-resistant transparent film is adhered to the substrate surface on which the colored pixels are provided via a heat-resistant transparent adhesive layer having a thickness that fills the level difference between the colored pixels. Color filter.