JPH04109221A - Color filter for liquid crystal display device and method for manufacturing the same - Google Patents

Abstract

PURPOSE:To decrease the effective resistance value of a common electrode and to prevent a defect such as a display irregularity by bringing the common transparent electrode into contact with a conductive light shielding film. CONSTITUTION:The color filter is formed by selectively etching away a protection film 21 which covers color filter layers 17 - 19 and a light shielding film 15 by utilizing step parts 26 between the color filter layers 17 - 19 and the film 15, forming a transparent electrode 22 thereupon to bring the transparent electrode 22 into contact with the film 15, and utilizing even the film 15 as part of the electrode. The film 15 is a metallic conductor, so the film sticks on a glass substrate 12 tightly and is low in resistance. Consequently, the resistance of the common transparent electrode 22 can be decreased without increasing man-hours, and no display irregularity is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color filter and a method for manufacturing the same, and more particularly to a color filter that enables color display by being used in a liquid crystal display device and a method for manufacturing the same.

[Conventional technology]

One type of liquid crystal display device capable of color display is one that uses color filters. Its typical structure is shown in FIG. A sealing member 13 is placed between a pair of glass substrates 11 and 12.
The liquid crystal 14 is enclosed using a liquid crystal. A light shielding film 15 is formed on the lower substrate 12 and defines a predetermined pattern of windows 16. On this window 16 is a dyed layer for color display, that is, R.
(red), G (green), B (blue) color filter layers 17.18
．． 19 is formed. These three color filter layers or 1
They are combined as a unit and display the color of one pixel.

The color filter layer 17, 18, 19 is covered with an organic dye layer protective film 21, and an indium tin oxide electrode which is a common electrode for all the color filter layers 17, 18, 19 of the lower substrate 12 is placed on top of the organic dye layer protective film 21. A transparent electrode 22 made of (ITO) is provided.

Furthermore, a surface protection film 23 is provided on the transparent electrode 22. A thin film transistor 24 is formed on the upper substrate 1 for applying a signal voltage between the upper substrate 1 and the common transparent electrode 22 to drive the liquid crystal.

The light shielding section 15 is also called a black matrix or a black mask, and prevents unnecessary light from passing through areas other than the pixel area, thereby increasing display contrast. The light shielding portion 15 is made of chromium (Cr), molybdenum (Mo), aluminum (A1), or other metal. Color filter layers 17, 18, and 19 are formed on the substrate 12 by a dyeing method, a pigment dispersion method, a printing method, or the like.

[Invention or problem to be solved]

If the common transparent electrode 22 has a high resistance, it may cause defects such as uneven display of pixels, so it is desirable that the resistance be as low as possible. However, if an attempt was made to increase the thickness of the transparent electrode 22 in order to lower the resistance, there was a risk that the light transmittance would also decrease. In particular, on a color filter that is not resistant to heat, the transparent electrode layer cannot be heated sufficiently, and the resistance tends to be high.

Furthermore, in order to reduce the resistance, it is possible to consider a method of laminating a metal pattern in a grid pattern on the transparent electrode 22, but in that case, one additional photolithography process is required, resulting in an increase in manufacturing costs.

An object of the present invention is to provide a color filter for a liquid crystal display device and a method for manufacturing the same, which can reduce the resistance of a common transparent electrode without increasing the number of steps.

[Means to solve the problem]

In the color filter according to the present invention, the protective film covering the color filter layer and the light shielding film is removed by selectively etching the protective film on the light shielding film using the stepped portion between the color filter layer and the light shielding film. A transparent electrode layer is formed from above, and the transparent electrode is brought into contact with a light-shielding film that is a conductor, and the light-shielding film is also used as a part of the electrode.

[Effect]

Since the light shielding film is a metal conductor, it adheres strongly to the glass substrate,
Moreover, it has low resistance. A low-resistance light-shielding film transmits voltage to the common transparent electrode, so display unevenness does not occur.

〔Example〕

A method of manufacturing an embodiment of a color filter according to the invention and the resulting structure will be described below with reference to FIGS. 1-4.

In FIG. 1, chromium (Cr) is deposited on a glass substrate 12.
A light shielding film 15 is formed on the grid using a metal having excellent etching resistance. Next, a color filter (R) is created using a dyeing method, a pigment dispersion method, a printing method, etc.

G, B) form 1.7.18.19. color filter 1
A protective film 21 is formed to cover 7.18.19, and an etched dummy film 25 made of molybdenum (M o ) whose etching rate is much slower than that of the protective film 21 is formed on the entire surface. Here, color filters 17.18.
The protective film 21 and the dummy film 25 formed on the step 19 are thinner than the flat portion. Then, the entire surface of the dummy film 25 formed is etched.

FIG. 2 shows this etching process. Color filter 17.
Since the thickness of the dummy film 25 is thinner than the flat surface on the color filter 17, 18, and 19, the stepped portion 26 between the light-shielding film 15 and the light shielding film 15 is thinner than the flat surface on the color filter 17, 18, and 19.
No.6 Ta-dama-membrane 25 will almost disappear. In this way, the protective film 21 is exposed on the light shielding film 15.

Etching is continued as it is, and the exposed protective film is etched together with the remaining tummy film 25.

Then, as shown in FIG. 3, the protective film 21 at the stepped portion 26 is further etched, and by the time the dummy film 25 on the flat portion on the color filter is completely etched, the protective film 21 at the stepped portion 26 is etched. 21 or removed by etching. In this way, the step portion 26, that is, the portion of the protective film 21 above the light shielding film 15 can be removed by etching without using photolithography, while leaving the protective film on the color filter. is exposed.

Next, as shown in FIG. 4, when a transparent electrode 22 such as TTO is formed on the entire surface, the transparent electrode 22 is exposed to the light shielding film 1 at the stepped portion.
5, the transparent electrode 22 and the conductive light-shielding film 15 are electrically connected in parallel.

An example in which the above embodiment was actually performed is shown below.

chromium (Cr) with a thickness of 50 to 200 nm as the light shielding film 15;
Color filter layers 17, 18, and 19 are formed to a thickness of 1.5 to 2.0 μm. As the color filter protective film 21, 200 to 11,000 nm of acrylic or silicone resin is coated.
-L, apply to the entire surface. Thereon, molybdenum (Mo) is formed as a dummy film 25 using a sputtering method of 20 to 1100 nm. Next, dry etching using CF4+02 gas (CF4 gas: 50-200 SCCM, oxygen 2-11
03CC, High frequency power: 5o ~ 1000W 9 catty crab 5
Etching was performed on the entire surface at a pressure of ~100 Pa). Molybdenum (MO) layer 25 of color filter layer 17, 18, 19''
When the etching was stopped when the color was completely removed, the protective film 21 other than those on the color filters 17, 18, and 19 was completely removed, and the chromium (Cr) surface of the light shielding film 15 was exposed. Next, indium tin oxide (ITO) was made by sputtering.
was deposited to form a transparent electrode 22. As a result, the actual resistance value was reduced to 1/20 or less compared to a conventional transparent electrode under the same conditions.

Although the present invention has been described in accordance with the examples above, the present invention is not limited to these examples. For example, various changes,
It will be obvious to those skilled in the art that improvements, combinations, etc. are possible.

[Effects of invention]

According to the present invention, the effective resistance value of the common electrode can be significantly reduced by bringing the common transparent electrode into contact with the conductive light-shielding film without increasing the number of photolithography steps.

Even if the resistance value of the transparent electrode itself is somewhat high, the applied voltage can be transmitted without decreasing, and defects such as display unevenness can be prevented.

Furthermore, the film thickness of the transparent electrode only needs to be thick enough to provide step coverage of the steps in the color filter layer, and there is no need to give much consideration to the resistance value, so the thickness should be adjusted under conditions that provide sufficient light transmittance. Since it can be determined, the transmittance can also be improved.

Figures for Explanation: FIG. 5 is a partial cross-sectional view of a liquid crystal display device equipped with a color filter according to the prior art.

In the figure, 11.12 17.18, glass substrate Sealing U part liquid crystal light shielding film 19 color filter layer color filter protective film common transparent electrode surface protective film Thin film I transistor tummy membrane step part

[Brief explanation of drawings]

Figures 1 to 4 are diagrams of the method for manufacturing a color filter according to the present invention and the structure of the color filter obtained by the patent applicant, Stanley Electric Co., Ltd., patent attorney, Kei Takahashi.

Claims (2)

[Claims] (1) a substrate; a light-shielding film made of a conductive material formed in a lattice shape on the substrate; a color filter member formed in the space of the lattice of the light-shielding film and thicker than the light-shielding film; and the color filter member. A color filter for a liquid crystal display device, comprising a protective layer formed thereon, and a transparent electrode layer that covers the protective layer and is in direct contact with and electrically connected to the light shielding layer. (2) forming a light shielding film in a lattice shape on a substrate; forming a color filter member thicker than the light shielding film in the space of the grid of the light shielding film; on the color filter member and the light shielding film; a step of laminating a protective film on the protective film, a step of laminating a predetermined layer of a material having an etching rate different from that of the protective film on the protective film, and etching the predetermined layer and the protective film to form a layer on the light shielding film. A method for manufacturing a color filter for a liquid crystal display device, comprising: removing a protective film to expose the light shielding film; and forming a transparent electrode film on the protective film and the light shielding film.