JPS5845009B2 - LCD display sealing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a glass seal for a liquid crystal display.

In more detail (i. In a field-effect liquid crystal display using nematic liquid crystal, when the two transparent electrodes and the peripheral sealing glass are locally heated with laser light to weld the electrode glass frit, ultrasonic waves are used to weld the electrode glass frit. The purpose is to achieve a complete glass seal with high adhesion when used in combination.

As shown in Figure 1, conventional liquid crystal display glass seals are made by printing glass frit on -753 of two transparent electrodes 1 and 3 in the shape of a thin frame as shown in 2, and in this state, the reserve is increased. Heat it up, then heat it in an electric furnace at a high temperature of over 500℃,
The printed frit was made into a display cell by welding 1.3 electrodes.

With the applied force S, the display cell is exposed to a high temperature of 500° C. or higher for at least 20 to 30 minutes in order to seal the glass.

Such liquid crystal display cells generally have the following problems.

1. Due to exposure to high temperatures of around 500°C, the glass substrate tends to deform, warp, etc., and its flatness tends to be impaired.

2. The electrical resistance value of the transparent conductive coating increases due to high temperature treatment.

3. The soda component of soda glass diffuses to the surface due to high temperatures.

For this reason, when used as a liquid crystal display, although the long-term reliability due to deterioration of the liquid crystal material is higher than that of a display cell using an organic seal, the characteristics as a so-called display generally tend to deteriorate.

In particular, liquid crystal molecules are twisted and aligned between two transparent electrodes,
In field-effect liquid crystal display systems in combination with polarized light, the arrangement of liquid crystal molecules at the electrode interface is an important factor in quality, and it has been difficult to obtain excellent liquid crystal display cells using glass seals.

Recently, instead of exposing the entire display cell to high temperatures to weld the printed glass frit and the two transparent electrode glasses, a laser beam or the like is used to locally scan the part to be welded using heat from the edge of the blade, and the other parts are A method of sealing the glass while raising the temperature is being considered.

FIG. 2 is an explanatory diagram of the glass seal by local heating described above.

A frame-shaped glass frit 7 is placed between the transparent electrode glasses 5 and 6.
is printed and inserted, and is irradiated with laser light from the laser light source 8 to seal while scanning the local heat-welded portion 9.

By using such a glass sealing method using local heat welding, the above-mentioned problems with the conventional glass sheeting method can be avoided.

However, this method also has the disadvantage that thermal distortion due to local heating remains and the adhesion of the glass seal portion is poor.

Under such circumstances, the present invention significantly improves adhesion by using ultrasonic waves in combination with the above-mentioned local gallo heat sealing of glass using laser light.

Moreover, when using the same local force and heat welding, when ultrasonic waves were also used, the same adhesion was obtained even if the laser output was halved.

When ultrasonic waves are not used together, a cell in which two transparent electrodes and a glass frit are locally heated and welded will peel off at the interface between the electrode glass surface and the glass frit in an adhesion test, but when ultrasonic waves are used together, The electrode glass begins to peel off.

In other words, it can be said that the adhesion between the electrode glass surface and the sealing glass frit is extremely strong.

The glass seal using a combination of laser light and ultrasonic waves according to the present invention has a number of features as described below.
In other words, since it is a local heating method, the entire display cell is not exposed to high temperatures, so even in field effect liquid crystal display methods, any method such as rubbing, oblique evaporation, or alignment using an organic surface treatment agent can be used. Can be used effectively.

Moreover, as shown in FIG. 3, transparent electrode glasses 1o, ii
When the force 11 is shaped by etching the thick portion 12 of the liquid crystal and two electrode glasses are combined, the glass sealing force method according to the present invention does not require a glass frit.

In addition, by using ultrasonic waves in combination, it becomes possible to use not only high-energy laser beams such as a carbon dioxide laser, but also low-energy laser beams such as a solid-state laser.

Types of laser light include CO2 laser YA,
There are G lasers, ruby lasers, semiconductor lasers, etc.

The glass seal according to the present invention can be applied to Pyrex glass and borosilicate glass substrates, whereas in the past, glass other than soda glass could not be used as electrode glass due to the problem of cracking due to differences in thermal expansion coefficients. It has many advantages.

Of course, the sealing force method of the present invention can also be applied to the hole sealing shown in FIG. 1.

[Brief explanation of drawings]

FIG. 1:1 is an explanatory diagram regarding the liquid crystal display and the glass seal on the body. FIG. 2 is an explanatory diagram of a glass seal according to the present invention. FIG. 3 is an example of an application of the present invention.

Claims (1)

[Claims] 1. In a liquid crystal display consisting of a nematic liquid crystal, two transparent electrode glasses enclosing it, and a glass frit material for peripheral sealing, the peripheral sealing glass is locally heated with laser light to weld the electrode glass and glass frit. A liquid crystal display sealing device characterized in that it uses ultrasonic waves in combination.