JPH11264970A - Liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display which is high in sticking strength by a seal material without causing a black mask to peel off. SOLUTION: A black mask 12 is formed of resin black on the rear surface of a front transparent substrate 13. At the frame part 12C of the circumferential edge of the black mask 12, a slit 12D is formed making one round of a display area. A seal material 15 is adhered directly to the glass surface of the front transparent substrate 13 by placing the seal material 15 on the frame part 12C where the slit 12 is formed and sticking the front transparent substrate 13 and a rear transparent substrate 13 together, so the front and rear transparent substrates 13 and 14 can tightly be stuck together to suppress peeling of the black mask 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display having a unique black mask structure.

[0002]

2. Description of the Related Art Conventionally, a black mask is formed in a liquid crystal display device. A thin film transistor (hereinafter, referred to as a TFT) as a switching element is provided on the black mask.
The purpose is to prevent light from being blocked, prevent color mixing of color filters, and improve contrast. This black mask is formed on the common substrate side facing the TFT substrate on which pixel electrodes, TFTs, etc. are formed in the liquid crystal display device.
The black mask is mainly formed by forming a metal chromium (Cr) film on a glass substrate serving as a common substrate by a sputtering method, and patterning the chromium film by a photolithography method. In recent years, a two-layer film structure in which chromium oxide having a low reflectance is formed on a chromium film has become common. Further, recently, resin black in which carbon or titanium (Ti) is dispersed in a resist has been adopted for a black mask. A specific structure is such that a black mask is formed on substantially the entire surface of the glass substrate facing the above-mentioned TFT substrate, and patterning is performed so that only a portion corresponding to the pixel electrode is opened. For this reason, a black mask is also formed on the peripheral portion of the glass substrate, so that light incidence and light leakage from the peripheral portion of the display area of the liquid crystal display device can be prevented.

[0003]

However, when chromium oxide is used for a black mask, there are problems that the cost is high and the reflectance is higher than that of resin black.

A black mask using resin black has a problem that the adhesion between the glass substrate and the black mask is poor and the black mask 2 is easily separated from the glass substrate 1 as shown in FIG. Note that in FIG.
Denotes a color filter, 4 denotes a common electrode, and 5 denotes an alignment film. For this reason, there has been a problem that after the assembly of the liquid crystal cell, moisture penetrates from the interface to cause inconveniences such as discoloration of the color filter and deterioration of the liquid crystal, thereby lowering the reliability of the liquid crystal display device. Further, when the TFT substrate and the common substrate are bonded together using a sealing material, the sealing material is completely placed on the black mask made of resin black. There is a problem that the liquid crystal cell is separated at the interface and decomposed. Therefore, when the sealing material is arranged around the outside of the black mask so that the glass and the sealing material are directly bonded, there is a problem that the outer shape of the panel becomes large and light leakage occurs around the panel.

[0005] The problem to be solved by the present invention is to determine what means should be taken to obtain a liquid crystal display device having a high bonding strength with a sealing material without peeling of a black mask. is there.

[0006]

According to the first aspect of the present invention,
In a liquid crystal display device in which liquid crystal is sealed between a pair of substrates, a black mask having a slit opened on one of the pair of substrates is provided, and the black mask on the slit of the black mask and along the slit is provided. The sealing material is provided continuously on the black mask. Therefore, according to the first aspect of the present invention, the one substrate and the sealing material are directly adhered to each other in the slit formed in the black mask. Separation from the one substrate can be suppressed, and since there is no gap between the sealing material and the black mask, there is no light leakage, and a display with a high contrast ratio can be obtained.

According to a second aspect of the present invention, in the liquid crystal display device according to the first aspect, the slit of the black mask is a slit formed so as to go around a display area.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the liquid crystal display device according to the present invention will be described below with reference to the embodiments shown in the drawings. FIG.
1 is a sectional view of a liquid crystal display device showing an embodiment of the present invention. As shown in FIG. 1, the liquid crystal display device 11 includes a front transparent substrate 1 as a common substrate on which a black mask 12 is formed.
3 and a rear transparent substrate 14 as a TFT substrate. A seal containing a glass fiber spacer having a diameter of about 6 to 7 μm for setting a distance between the substrates 13 and 14 via a predetermined gap. A liquid crystal 16 is sealed in a gap between these substrates, and is roughly configured. Although not shown in this embodiment, a well-known backlight system, a polarizing plate, and the like are provided.

First, the configuration on the front transparent substrate 13 side will be described. The front transparent substrate 13 is formed of transparent glass. On the rear surface of the front transparent substrate 13, a black mask 12 having a thickness of 2 μm and a color filter 17 forming a predetermined color arrangement in each pixel region surrounded by the black mask 12.
Are formed. A transparent ITO (indium tin oxide) is formed over the entire display area on the rear surface of the black mask 12 and the color filter 17 via an insulating film (not shown).
The common electrode 18 of e) is formed. Further, on the rear surface of the common electrode 18, a pre-alignment film 19 that is subjected to an alignment process over the entire display area is formed.

Here, the configuration of the black mask 12 will be described. The black mask 12 is made of resin black in which carbon or titanium is mixed in an acrylic resin, and is patterned using a photolithography technique and a wet etching technique. FIG. 2 shows a black mask 12.
FIG. 4 is a plan view showing a state where a common electrode 18 and a pre-alignment film 19 are formed on the substrate. As shown in FIGS. 1 and 2, the black mask 12 is formed over the entire rear surface of the front transparent substrate 13. The black mask 12 includes a matrix portion 12B in which a rectangular portion is formed at a portion corresponding to each pixel region in the display region and an opening 12A is formed, and a frame portion 12C surrounding the matrix portion 12B. The color filter 17 is formed in the opening as described above. A slit 12D is formed in the forehead portion 12C so as to go around the display area.
The front transparent substrate 13 is exposed from D. FIG. 3 is a cross-sectional view showing a state in which a sealing material 15 is formed on the forehead portion 12C so as to orbit along the slit 12D of the black mask 12 with respect to the front transparent substrate 13 shown in FIG. . The width of the forehead portion 12C is designed to be about 3 mm even when the slit 12D is provided.

Next, the structure of the TFT substrate 14 will be briefly described. The rear transparent substrate 14 is made of transparent glass, and has a pixel electrode 20 made of ITO corresponding to each pixel region on the front surface. The pixel electrode 20 has TF
T21 is formed to be connected. Although not shown, a gate line, a drain line, and the like are connected to the TFT 21, but these lines and the TFT 2
Numeral 1 is set so as to face the matrix portion 12B of the black mask 12 in a state where the front transparent substrate 13 and the rear transparent substrate 14 are bonded together. Then, the pixel electrode 20 or T
After the FT 21 or the like is formed, a rear alignment film 22 is formed on the entire display area on the front surface of the transparent substrate 14.

The above-mentioned front transparent substrate 13 side and rear transparent substrate 1
The liquid crystal display device 11 is configured such that the liquid crystal display device 11 is bonded to the fourth side via a sealing material 15 made of epoxy resin, and the liquid crystal 16 is sealed in the gap.

In this liquid crystal display device 11, the front transparent substrate 13 and the rear transparent substrate 14 are in a state where the sealing material 15 is placed on the forehead portion 12C of the black mask 12 of the front transparent substrate 13. Since the front transparent substrate 13 and the sealing material 15 are directly bonded to each other through the slits 12D, the black mask 12 has an effect of being held on the front transparent substrate 13 by the sealing material 15. Therefore, it is possible to suppress the black mask 12 from being separated from the front transparent substrate 13. Especially,
The sealing material 15 made of epoxy resin is 150 to 160 ° C.
It is thermally cured to a degree and has high bonding properties with glass. Also, UV
Cured resin can also be applied. In the present embodiment, since the slit 12D of the black mask 12 is narrower than the sealing material 15, even if a slight misalignment occurs when the sealing material 15 is placed on the substrate 13, both ends of the sealing material 15 Is located outside the both ends of the slit 12D, so that there is almost no leakage light.

Although the embodiments have been described above, the present invention is not limited to the embodiments, and various changes accompanying the gist of the configuration are possible. For example, in the above-described embodiment, the black mask 12 is formed so as to go around the slit 12D in the forehead portion 12C.
The shape of D is not limited to this, but may be a wavy slit. In addition, not the slit
As shown in (1), an opening 12E may be formed in which the black mask 12 is intermittently opened. In short, an opening 12E may be used as long as the sealing material 15 and the glass surface are directly joined. In addition,
The configuration of the liquid crystal display device 11 is a transmissive liquid crystal display device having a reflective plate in addition to the transmissive liquid crystal display device as in the present embodiment, and the present invention can be applied.

[0014]

As is apparent from the above description, according to the present invention, the black mask does not peel off,
It is possible to obtain a liquid crystal display device with high bonding strength by a sealing material and a high contrast ratio. Therefore, the production yield of the liquid crystal display device can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a plan view showing a configuration on a front transparent substrate side of the embodiment.

FIG. 3 is a sectional view of a main part of the embodiment.

FIG. 4 is a main part plan view showing another embodiment of the liquid crystal display device according to the present invention.

FIG. 5 is a sectional view of a main part of a conventional liquid crystal display device.

[Explanation of symbols]

 Reference Signs List 11 liquid crystal display device 12 black mask 12B matrix part 12C frame part 12D slit 12E opening 13 front transparent substrate 14 rear transparent substrate 15 sealing material 16 liquid crystal

Claims (2)

[Claims] In a liquid crystal display device in which liquid crystal is sealed between a pair of substrates, a black mask having a slit opened on one of the pair of substrates is provided, and a black mask is provided on the slit of the black mask and A liquid crystal display device, wherein a sealing material is continuously provided on the black mask along a slit. 2. The slit of the black mask,
2. The liquid crystal display device according to claim 1, wherein the slit is formed so as to go around the display area.