JP2744994B2 - Method for manufacturing multicolor display device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multicolor liquid crystal display device using a color filter, and more particularly, to providing a transparent conductive film on a color filter to reduce a driving voltage. The present invention relates to a method for manufacturing a multicolor liquid crystal display device that can be operated.

[Summary of the Invention]

The present invention forms a plurality of color filters made of a polymer on a substrate, then, after forming a transparent conductive film, applying a photoresist, exposing and developing the photoresist using the color filter as a photomask, By removing the transparent conductive film by etching and leaving and forming the transparent conductive film only on the color filter, the formation of the transparent electrode on the color filter does not require a special photomask or accurate alignment, and the process becomes self-aligned. This greatly simplifies the operation and improves the accuracy.

[Conventional technology]

In recent years, the technology of multi-color display has been advanced by turning on / off the light passing through a color filter in a cell with a liquid crystal shutter. At this time, a color filter was first formed on the liquid crystal drive electrode, but there was a problem that the drive voltage increased due to the voltage drop due to the color filter. Recently, the color filter and pattern were formed on the color filter. The need to match and form a transparent electrode has arisen.

FIG. 3 is a cross-sectional view of a conventional example of a multicolor display device in which a transparent electrode is formed on a color filter, and a method of manufacturing the same will be described below.

Reference numeral 31 denotes a glass substrate on which ITO transparent electrodes 32 are placed.
Are formed in a predetermined pattern. A color filter 33 is formed on the ITO electrode by an electrodeposition method, a dyeing method, a printing method, or the like. In the electrodeposition method, a colored film is deposited on an electrode by selectively applying a voltage to the electrode from a solution containing a polymer and a dye. The dyeing method is a method in which a dyeable polymer such as photosensitive gelatin is applied, a pattern is formed by photolithography, and each color is dyed. The printing method, as the name implies, prints multicolor inks precisely on a substrate.

It should be noted that the ITO transparent electrode 32 is not required for a dyeing method other than the electrodeposition method or a printing method. Numeral 34 denotes a transparent electrode on the color filter, and FIG. 4 shows a manufacturing process thereof. As shown in FIG. 4 (a), the entire surface of the substrate 31 with the color filter 42 is covered with ITO.
The transparent conductive film 43 is formed by sputtering or the like. Next, as shown in FIG. 4B, a photoresist 44 is applied, the photomask 45 is accurately aligned with the color filter pattern, and light 46 is irradiated and exposed. Next, the photoresist is developed as shown in FIG. Finally, as shown in FIG. 4 (d), the exposed ITO is removed by etching, the photoresist is removed, and a transparent electrode 34 is formed on the color filter.

Returning to FIG. 3, the method of manufacturing the multi-color display device will be described below. Thus, a multi-color display device is obtained.

[Problems to be solved by the invention]

The multicolor display device as shown in FIG. 3 has no voltage loss due to the color filter and is suitable for low-voltage driving. However, as shown in FIG. 4, a transparent electrode is formed on the color filter. Requires a complicated process. In particular, since the electrode pattern of the display device is fine, a photomask having high precision is required, and its alignment is also required to be extremely accurate. Therefore, the manufacturing equipment is complicated and cannot be manufactured easily.

[Means for Solving the Problems] In order to solve the above-described problems, the present invention uses a color filter to which a color filter or an ultraviolet absorbing substance is fixed as a photomask, and patterns a transparent electrode on the color filter by self-alignment. How to

[Action]

Since the color filter is formed as a photomask by self-alignment, a high-precision photomask is not required, and no accurate alignment is required, so that the process is greatly simplified and facilitated.

〔Example〕

Many general photoresists have a photosensitive wavelength in the ultraviolet region, and the object of the present invention can be achieved if the color filter completely absorbs the ultraviolet region.

However, the pigment used in the color filter attaches importance to spectral characteristics in the visible region, and thus does not have a characteristic of completely cutting off the ultraviolet region. Further, since polymers used for color filters are also required to have transparency, there are few polymers that sharply cut an ultraviolet region. Therefore, in practice, when the color filter is thin, it is slightly exposed to the photosensitive wavelength region of the photosensitive substance, so that the color filter is also exposed, and the photoresist remains on the color filter even after development. However, the patterning of the transmission electrode is not successful.

In order to solve the above problems, the thickness of the color filter is made sufficiently thick to reduce the transmittance of ultraviolet rays, or if a color filter is mixed with an ultraviolet absorber that sharply cuts the ultraviolet region. Although good, mixing UV absorbers into the material used to form the color filters is problematic. For example, when a color filter is formed by a dyeing method, the color filter material itself is exposed to ultraviolet light, so that mixing an ultraviolet absorber therein prevents exposure at the time of forming the color filter and causes poor development. It will be. In addition, in the electrodeposition method, mixing an ultraviolet absorber in a solution of a polymer and a dye disrupts the balance of the electrodeposition reaction itself, and adversely affects the deposition of a film. Thus, the present inventors have found a method of fixing an ultraviolet absorber from a solution of the ultraviolet absorber into the color filter as a means for mixing the ultraviolet absorber into the color filter after forming the color filter.

In general, there are many substances as ultraviolet absorbers, but few can be fixed to a polymer, and most of them can be mixed. However, among dyeing aids for improving the light resistance of fibers and the like, there are dyeing assistants that effectively absorb ultraviolet light and dye the polymer. For example,
A hydroxybenzotriazole derivative represented by the following structural formula is used for such a purpose.

In addition, those which are called fluorescent brighteners also have an ultraviolet absorbing ability and can be used in the present invention.

These substances are made into a solution, fixed to the polymer in the same manner as in general dyeing, and can add ultraviolet absorbing ability. This makes it possible to use the color filter itself as an ultraviolet absorbing film by a simple method even after forming the color filter as in the present invention.

Hereinafter, the effects of the present invention will be specifically described based on examples and comparative examples.

Embodiment 1 FIG. 1 is a sectional view of a multicolor liquid crystal display device manufactured according to the present invention. The manufacturing method will be described with reference to FIG. 1. Reference numeral 1 denotes a glass substrate on which a transparent electrode 2 made of ITO is formed in a predetermined shape. Reference numeral 3 denotes a color filter in which a transparent electrode 2 was selectively deposited from a solution containing a polymer and a dye by applying a voltage to the transparent electrode 2 to form a precipitate on the transparent electrode. In this example, the polymer used was a polyester-melamine resin, and the film thickness of the color filter was 1.0 μm. Next, the color filter 3 was immersed in an aqueous solution of an ultraviolet absorber Sumipon UL (manufactured by Sumitomo Chemical) and dyed with the ultraviolet absorber at 90 ° C. Thereafter, the color filter was completely cured, and the transparent electrode 4 was formed in the step shown in FIG. As shown in FIG. 2A, the entire surface of the glass substrate 1 having the color filter 22 is covered with IT.
The O transparent conductive film 23 is formed by sputtering or the like.

Next, as shown in FIG. 2 (b), 24 photoresist OFPR-8
00 (manufactured by Tokyo Ohka Co., Ltd.) is applied, and light 25 is irradiated from behind to expose the color filter as a photomask. Next, as shown in FIG. 2C, the photoresist is developed. Finally, as shown in FIG. 2 (d), the exposed ITO was removed by etching, the photoresist was removed, and a transparent electrode 4 was formed on the color filter. As described above, in this embodiment, although the transparent electrode was formed on the color filter by a very simple method, there was no displacement between the color filter and the transparent electrode because of the self-alignment. Hereinafter, returning to FIG. 1, the method of manufacturing the multicolor display device will be described. The liquid crystal is disposed between the substrate 1 on which the color filter and the transparent electrode are formed and the second substrate 6 on which the transparent electrode 5 is formed. 7, a good display quality with a low voltage drive was obtained by a simple method.

(Example 2) The color filter 3 in FIG. 1 was patterned by exposing and developing photosensitive gelatin, and then dyed by 1.0 μm.
m. The color filter thus formed was immersed in an aqueous solution of a copper complex-based ultraviolet absorber Chibafast N (manufactured by Ciba Geigy) and dyed at 60 ° C. Thereafter, a multicolor display device was produced in the same manner as in Example 1. Example 1
The same effect was obtained.

(Example 3) The color filter 3 in Example 1 was replaced with a fluorescent whitening agent Uv.
It was immersed in an aqueous solution of itex BAC (manufactured by Ciba Geigy) and dyed at 70 ° C. Thereafter, a multicolor display device was produced in the same manner as in Example 1, and the same effect as in Example 1 was obtained.

Example 4 The thickness of the color filter 3 in Example 1 was set to 2.0 μm.
m, and a multicolor liquid crystal display device was produced without dyeing the ultraviolet absorbent. The thickness of the color filter was large, so that the ultraviolet absorption was sufficient and the same effect as in Example 1 was obtained. Was.

(Comparative Example 1) The thickness of the color filter 3 in Example 1 was set to 1.0 μm.
When a multi-color liquid crystal display device was manufactured without dyeing the ultraviolet absorber, the color filter became insufficient in ultraviolet absorption, and the color filter was also exposed, resulting in poor patterning of the transparent electrode. It has become.

〔The invention's effect〕

As described above, as specifically described in Examples, the method of forming a transparent electrode by self-alignment using a color filter according to the present invention as a photomask is a simple method because the color filter can be a complete ultraviolet shielding mask. There is no displacement between the color filter and the transparent electrode on the color filter, the yield can be expected to be improved, and a multi-color display device with good display quality driven by low voltage can be realized.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of a multicolor display device according to the present invention,
2 is a process diagram for forming a transparent electrode on a color filter according to the present invention, FIG. 3 is a sectional view of a conventional multicolor display device, and FIG. 4 is a process diagram for forming a conventional transparent electrode on a color filter. It is. 1,6,31,36, ... Substrate 2,4,5,32,34,35 ... Transparent electrode 3,22,33,42 ... Color filter 7,37 ... Liquid crystal 24,44 ... Photoresist 25, 46 UV light 45 Photo mask

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-57-34520 (JP, A) JP-A-61-116333 (JP, A) JP-A-61-198216 (JP, A) JP-A-63-1982 70828 (JP, A) JP-A-1-277202 (JP, A) JP-A-2-77014 (JP, A)

Claims (2)

(57) [Claims] In a method of manufacturing a multicolor display device using a color filter, a plurality of color filters made of a polymer are formed on a substrate, and then a transparent conductive film is formed.
A multi-color display device comprising applying a photoresist, exposing and developing the photoresist using the color filter as a photomask, etching away the transparent conductive film, and forming a transparent electrode only on the color filter. Manufacturing method. 2. A method for manufacturing a multi-color display device according to claim 1, wherein a UV-absorbing substance is fixed to said color filter, and then a transparent conductive film is formed and a photoresist is applied, and said color filter is used as a photomask. A method for manufacturing a multicolor display device, comprising exposing and developing a photoresist to form a transparent electrode only on a color filter.