JPS6326634A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To accurately align a filter substrate with another substrate at a high speed by forming a reflection preventive member for exposure for an alignment pattern type in an area where the alignment key of the substrate on which a filter is formed is formed. CONSTITUTION:The entire surface of a transparent substrate 1 is coated with a negative dye base material, part of the base material is polymerized by performing ultraviolet-ray exposure through a specific mask, and the base material at the unpolymerized part is removed by development. The specific remaining area is dyed in red to form a red filter 2 and a red part 3 much wider than the alignment key to be formed thereafter is left in the area where the alignment key is to be formed. This thin film red part 3 absorbs an ultraviolet ray for exposure used at the time of the alignment key type and prevents its transmission, thereby preventing an ultraviolet ray from the substrate 1 from being reflected. Consequently, the sharp fine alignment key can be formed in the area of red and the color filter substrate and the other substrate are aligned with each other by optical pattern recognition technique fully automatically, accurately, and speedily.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to flat panel displays, particularly color liquid crystal displays.

Conventional liquid crystal display devices operate at low voltages, can be made large in area even if they are thin, and have features such as being able to display full color. Among these, devices that combine a filter in which fine unit filter elements of the three primary colors red, green, and blue are arranged according to a predetermined regulation and a liquid crystal as a light shutter are attracting attention as devices that can display good color. . Of this device,
The mainstream is that color filters are arranged on one transparent substrate, drive units such as thin film transistors (TPT) and diodes are arranged on the other substrate, and the drive units and unit color filter elements form a display unit. It is. In this case, it is necessary to bond both substrates while accurately controlling the relative position between the open substrates with an alignment accuracy of several μm. Therefore, alignment keys ν for controlling relative positions are formed on both substrates, and by controlling the relative positions of these keys, both substrates are bonded. Each of these five keys is designed to have a width of approximately 10 μm, and the edges thereof must be clearly resolved with good contrast.

Problems to be Solved by the Invention The color filter is formed on a transparent substrate as described above. When using a negative-type dyeing machine in which the ultraviolet rays remain after polymerization as a component of the filter, the irradiated ultraviolet rays are reflected on the back side of the transparent substrate, so the photomask allows the ultraviolet rays to reach areas that should not be irradiated. Also, extra reflected light will be irradiated. Therefore, extra dyeing base material remains around the fine pattern of the dyed base material that is supposed to remain, causing a so-called fogging phenomenon. That is, the polymerized dyed base material remains around the original dyed base material pattern even after development.

As a result, when the above-mentioned fine alignment key is simultaneously fabricated using color filter components, pattern bleeding occurs around the key due to a fogging phenomenon.

The alignment key with this bleeding has a drawback that it becomes difficult to perform accurate relative positioning of the open substrate.

Means for Solving the Problems According to the present invention, an antireflection member for exposure light for an alignment key pattern type is formed in a region of a substrate forming a filter where an alignment key is formed.

Operation Alignment Key Type 1 Approximately before the alignment key is formed, a thin film that is larger than the alignment key and is used for exposure, such as absorbing but not transmitting ultraviolet rays, is formed as an anti-reflection member in the alignment key forming part, so that reflected ultraviolet rays can be prevented when forming the alignment key. It is possible to prevent the formation of excess residual patterns around the alignment key due to this process, and it becomes possible to form a precise alignment key as designed, accurately position the substrate, and bond it.

Embodiment An embodiment will be described following the steps shown in FIG. First, a negative dyed base material is applied to the entire surface of the transparent substrate 1 on which the color filter will be formed, a part of the base material is polymerized by exposure to ultraviolet light through a predetermined mask, and the non-polymerized parts of the base material are developed by development. Remove.

This remaining predetermined area is dyed red to form a red filter 2, and at the same time, in the area where the alignment key is to be formed,
Red area 3 that is sufficiently wider than the alignment key that will be formed later
(Figure 1a). The thin red film portion 3 made of a part of the dyed base material formed in this step absorbs and prevents transmission of ultraviolet rays for exposure used in the alignment key format, and prevents reflection of ultraviolet rays from the substrate 1. .

By repeating the same process, green and blue filters 4 and 5 made of negative dyed base material are formed (Fig. 1b
). Furthermore, as shown in FIG. 1(c), by the same process,
A light shielding part 7 made of a black layer of a negative dyed base material and an alignment key 6 are simultaneously formed at the boundary of each filter.

At this time, the exposure ultraviolet light from a photomask (not shown) is absorbed by the red portion 3 and is not reflected from the back surface 8 of the substrate 1 (broken line), so that alignment keys 6 can be formed according to the mask pattern. Both the key 6 and the red part 3 are formed of the same material as the filter component, so there is no additional process.

An enlarged plan view of the thus formed alignment key 6 and portion A of the red portion 3 is shown in FIG. Key 6 is created by pattern-exposure of the dyed base material formed on the entire surface with ultraviolet rays (shown in Figure 1 C) and development in 7 steps.
The red region 3 absorbs and blocks ultraviolet rays, reducing the reflected light (broken line) from the back surface of the substrate 1, so there is no smearing of excess base material around the key 6, and the patterned key 6 had sharp boundaries.

FIG. 3 shows a substrate 1 on which a filter and an alignment key are formed, an alignment key 6 and an alignment key 13 of a transparent substrate 10 on which display elements 30 such as thin film transistors and other display wiring are formed, and then bonded. It shows the state where it is adhered with agent 12. 20 indicates a portion of the filter on the substrate 1. A liquid crystal 11 is sealed between the substrates 1 and 10.

In this way, it is possible to form fine and clear alignment keys in the red area, and the color filter substrate and other substrates can be precisely and quickly aligned fully automatically using optical pattern recognition technology. It becomes possible,
It has become possible to improve the productivity of liquid crystal display devices and eliminate defects caused by alignment errors. The substrate structure shown in Fig. 1 uses a combination of color filter elements with different main transmission wavelengths to form an alignment key and an antireflection member, and there is no increase in process as in color filter type 1. There are no inconveniences mentioned above.

Although the present invention has been explained based on the above embodiments, the red part 3 serving as the anti-reflection member does not necessarily have to be red (and the alignment key 6 does not necessarily have to be black either. Of course, any combination of hues that provides a clear contrast is good.

Effects of the Invention As described above, according to the present invention, it is possible to form a fine and clear alignment key on a substrate on which a filter is formed, and to quickly and accurately align the filter substrate with other substrates. This greatly contributes to improving the yield of high-precision liquid crystal display devices.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of the manufacturing process of a color filter used in a liquid crystal display device according to an embodiment of the present invention, Fig. 2 is a plan view of part A in Fig. 1, and Fig. 3 is a partial cross-sectional view of the liquid crystal display device. be. 1.10... Board, 2... Red filter, 3... Red part, 4... Green filter, 5... Blue filter, 6...
...Alignment key, 7...Black light shielding part. Name of agent: Patent attorney Toshio Nakao and one other person Figure 1? 2nd “No 3rd figure

Claims (3)

[Claims] (1) A filter is provided on one main surface of the first substrate, a second substrate facing the first substrate and both main surfaces of the first substrate are opposed to each other, and the first substrate 1. A liquid crystal display device, characterized in that an anti-reflection member for light for forming the alignment key is formed on the alignment key forming portion on the first substrate that defines the relative position of the first substrate and the second substrate. (2) The liquid crystal display device according to claim 1, wherein the antireflection member is constituted by a filter component. (3) The liquid crystal display device according to claim 1, wherein the antireflection member prevents transmission of light for forming alignment keys.