JPS5950426A - Assembling and press sticking method of liquid crystal display panel - Google Patents

Abstract

PURPOSE:To enable the formation of a panel having a uniform cell thickness by giving a temp. difference in the part of a device for adhesive fixing to be brought into contact with upper glass and the part to be brought into cntact with lower glass in the stage of adhering and fixing two sheets of the upper and lower substrates. CONSTITUTION:The panel under press fixing with an assembly jig is illustrated. The entire part of the jig is first put into a furnace and the temp. is elevated. The part 48 in contact with upper glass 44 is cooled by the water 42 or the like run thereon and therefore the part 48 is in a lower temp. than the part 49 in contact with lower glass 46. The reliability and long-term reliability of the panel are thus improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for assembling and press-bonding liquid crystal display panels in which the upper and lower substrates have different coefficients of thermal expansion, making the thickness uniform and increasing the strength of the panel.

Conventional methods for press-bonding liquid crystal display panels can be broadly classified into the following types. ■The organic resin is heat cured and the upper and lower substrates are bonded. ■Glue the upper and lower substrates with ultraviolet curing resin. ■Glue the upper and lower substrates with low melting point glass. All of the above methods involve a heating process, but the one using ultraviolet curable resin (2) has a relatively low temperature and hardens in a short time, but there are problems with the strength and reliability of the assembled panel. However, it has not been put into practical use. Methods (1) and (2) are currently commonly used in panel assembly processes. ζ This section will explain method (2), which allows panels to be assembled at a relatively low temperature.

FIG. 1 shows an example of a method for assembling and crimping panels by method (2).

Upper board of panel 11. Underwear board I2 is a board j with a flat surface:
(The pressure is applied from above and below by , 14, and the pressure is
The weight of the spring J5 and the jig 16 is applied to the shibaneru. If it is left in a high-temperature oven with pressure applied, the sealant printed on the seal portion 17 will harden, and the upper and lower substrates will be fixed and crimped. When the upper substrate 11 and the lower substrate 12 of the panel were made of the same moonstone and had the same coefficient of thermal expansion, the panel did not deform even when the temperature was returned to room temperature after fixing and crimping. However, for the following liquid crystal panels, upper and lower substrates must have different Toga sizes. ■Active matrix liquid crystal display device using silicon substrate, ■TPT liquid crystal display device using quartz glass.

In (2), the substrate +d constituting the TPT element is made of quartz glass, but if the counter substrate is also made of quartz glass, the price of the V plate becomes extremely expensive. Therefore, the substrate constituting the TPT element is made of quartz glass, and the opposing substrate is made of other f.
This is why ILT type glass is used. Figure 2 is a diagram showing the stress applied to the panel when glasses with different coefficients of thermal expansion (in this example, the upper glass has a larger coefficient of thermal expansion) are bonded to B1 at high temperature and then returned to room temperature. . Naturally, stress is also applied to the adhesive hardening agent 22 used to seal the panel, but here we do not consider the elasticity of the adhesive hardening agent 22, and the adhesive hardening agent is completely fixed after heating and curing. We will proceed with the explanation assuming that this is the case. Since the upper glass 21 has a higher coefficient of thermal expansion than the lower glass Z3, when the adhesive is cured at a high temperature and then returned to room temperature, the upper glass shrinks and the lower glass is pulled outward. This force is applied to the upper glass 21. Adhesive hardener 22. It is distributed between the lower gaskets 2'3. If the lower glass 23 is made entirely of quartz glass and the upper glass 21 is made of borosilicate glass, and the length of the inside of the bonded part is 5 cm long and 4 m wide, the forces 24 and '25 applied in the vertical direction can be roughly summarized as follows. The different coefficients of thermal expansion are as follows.

・Quartz glass 5゜5
When the adhesive is cured at °C and then cooled to room temperature (20 °C) -1, each glass shrinks by the following value.

・Quartz glass △A"= 5.5 X river -'X (150ftl
:, 1-201'O) x 50 bias) = 3.58
X1. Om, A borosilicate gas, W' = 32.5 X Hl-'X (150℃1
-2010 ) X 50 (ma) = 2.11 X
Young's modulus of 10 to approximately 7 x 3”fmx for any glass
2, the forces applied to each glass should be equal, and are as follows.

F,: EX ((Δe-hec)/A) x
S/2=7. OX 10”X (],,75XH
I"""150)
Since it is JI, the pressure f applied to one frontage is divided by 3, and then f is 1.231 (y, /+-).

Generally, when stress is applied to glass over a long period of time, the strength is
This is said to be 0.7 "embryo s'", and the above-mentioned heat curing method was unreliable as there was a possibility that the 1iJl VC&G glass would break.

Fig. 3 d1 shows an example in which a liquid crystal panel is formed with one substrate having a thin thickness using the conventional adhesive curing method.When the panel is heated and cured and then returned to room temperature, the cell thickness in the central part 34 of the panel is 70 mm ψ in the peripheral part 35 of the panel. It has been found that due to the stress on the two substrates of the much larger p1 panel, the panel's cell density tends to be non-uniform.

The present invention eliminates the above-mentioned conventional drawbacks, and its purpose is to improve the reliability of LCD panels in which the upper and lower substrates have different properties, improve the long-term strength of the panel, and prevent breakage. The purpose is to prevent this problem and improve the quality of a liquid crystal panel in which the upper and lower substrates have different coefficients of thermal expansion, such as the uniformity of the gap between the liquid crystal panels.

FIG. 4 is an example of a crimping method using the liquid crystal display panel assembly jig according to the present invention. The entire jig is placed in a furnace in the state shown in B to raise the temperature, but the part 48 in contact with the upper glass 44 is cooled by flowing water or gas 42ff, and the part 49 in contact with the lower glass 46 is cooled. , the temperature is low. The actual temperature of the upper glass is 100℃
, the temperature of the lower glass is 200°C), and the stress applied to the glass in this case can be estimated in the same way as before.

The amount of shrinkage of the glass is: - Quartz glass △A = 5.5 ×IO-'X (200-20)
50= 4.95 X Itl □□-ff
1lll 窶i"i; 2 /'/ Las Δβ' = 32
．． 5 X Hl 'X (100-2(1) x 50
= 1゜3
/2=, 22.5 t: Add 1α to the pressure f applied to the fin opening of Tagarasu 1, then f = 0.5
It can be made smaller than the long-term failure limit of 0.7Kha+'' for general glass panels.In this way, by creating a temperature difference between the part in contact with the upper glass and the part in contact with the lower glass, the reliability of the panel is increased. It was possible to create a panel with uniform cell thickness.

FIG. 5 is a sectional view of a panel assembled by the assembly and crimping method according to the present invention. Since almost no stress is applied to the upper and lower substrates 51 and 53 at room temperature, C/1. There is no unevenness in thickness, and the long-term reliability of the panel is excellent.

Any case where the stress applied to the panel is reduced by providing a temperature difference between the upper glass and the lower glass is considered to be within the scope of this patent.

[Brief explanation of the drawing]

Figure 1 shows the conventional thermocompression bonding method, where the sealant is
Organic resin is used. Figure @2 is a diagram showing the stress applied to the panel when the sealing agent (adhesive) is cured at high temperature and then returned to room temperature when the panel is bonded using the conventional thermocompression bonding method. FIG. 3 is a cross-sectional view of a panel when one of the substrates is thermocompression bonded using a thin plate using a conventional method. FIG. 4 is a diagram showing a method for assembling and crimping a liquid crystal panel according to the present invention.
This is an example of creating a difference in temperature between the parts where the upper glass and the lower glass touch. FIG. 5 is a cross-sectional view of a panel assembled by the assembly and crimping method according to the present invention. 1. Since no stress is applied to the lower substrate, unevenness in cell thickness does not occur. 11... Upper glass plate (substrate) I2... Lower glass plate (substrate) I3... Flat plate 14 for holding down the upper glass plate...
Flat plate 15 that presses the lower glass plate... Spring 16... Crimping 1i', I-jig tool 17, sealing part 21... Upper glass plate (substrate) 22... Seal part (adhesion) Curing agent) z3...Lower glass plate (substrate) 24...Stress in shrinkage direction...Outward stress 31...Thin upper glass plate (substrate) 32...Sealing part; (: (Tsukudagawasu board (substrate)) 3.1... Panel center phase 3 35... Panel peripheral area 41... Water or gas 3ii; no L pipe 42...
Water pot/koha gas 43...crimping jig 4a...soil 1! II Gauss plate (substrate) 45... Seal part 46... Lower glass plate (substrate) 47 Fist... Spring, I8... Flat plate holding down the upper glass plate 49...
Flat plate 51 that presses the lower glass plate... Thin upper glass plate (substrate) 52... Seal portion 53... Lower glass plate (substrate) 2 Applicant: Suwa Seikosha Co., Ltd. Agent Patent Attorney Mogami: Figure 1, Figure 3, Figure 4, Figure 4

Claims (1)

[Claims] (11) In a liquid crystal display panel formed by sandwiching a liquid crystal layer between two substrates, the two substrates have different coefficients of thermal expansion.
When assembling a panel using itr↓, when identifying the two upper and lower boards by adhesion, an adhesion fixing jig or device d
However, there is a difference in temperature between the part in contact with the upper glass and the part in contact with the lower glass! Features a crimping method for assembling LCD panels. (2174iJ) The liquid crystal display according to claim 1, wherein the temperature of the portion of the two substrates in contact with the substrate with a higher expansion coefficient is lower than that in contact with the substrate with a lower expansion coefficient. Panel assembly crimping method.