JPH08201820A - Liquid crystal display device and its manufacture - Google Patents

Abstract

PURPOSE: To enhance the sealing effect of a liquid crystal display device by surrounding a liquid crystal with a double structure of a sealing material to be contacted with a chemical substance in the non-electric field plating process and a sealing material which does not contact with chemical substance in the non-electric field plating process. CONSTITUTION: The peripheries of the surfaces of glass transparent substrate boards 1-1, 1-2 where transparent electrodes 2-1, 2-2 are formed, are surrounded by a sealing material 4 as adhesives of thermosetting epoxy series, and this sealing material 4 is surrounded by another portion of sealing material 5 of the same composition while an air layer is interposed. By mean of non-electric field plating, a metal plating 6 is provided over the surfaces of the transparent electrode 2-1 drawn out to outside the sealing material 5 formed on the surface of the transparent base board 1-1 and another transparent electrode 2-3 connected with the signal input terminal of a liquid crystal drive IC 9. Because a chemical substance of non-electric field plating is attached to the sealing material 5 situated outside, a secular corrosion will occur. However, the sealing material 4 situated inside is free from corrosion and can maintain the sealing function, because the material 4 is not in contact with the chemical substance of the non-electric field plating.

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 device used in laptops, notebook computers, portable devices and the like.

[0002]

2. Description of the Related Art C of a conventional simple matrix liquid crystal display device
An OG (chip on glass) mounting structure is shown in FIG. 9. Here, one end of a plurality of transparent electrodes 2-1 for applying an electric field to the liquid crystal is arranged to be connected to the signal output terminal of the liquid crystal driving driver IC 9. Further, a transparent electrode connected to the signal input terminal of the liquid crystal driving driver IC 9 is arranged, and the bumped liquid crystal driving driver IC 9 is connected to the transparent electrode by an anisotropic conductive film, Ag paste or the like.

[0003]

The transparent electrode is made of In and S.
Since it is made of a material made of oxide of n, it has a high resistance value and a sheet resistance value of 10Ω / □ at a mass production level. Therefore, the liquid crystal drive driver IC has an IC drive potential or There is a problem that the display quality is poor due to the unevenness in the resistance value of the transparent electrode that supplies a signal to the device and the unevenness in the connection resistance, which causes unevenness in contrast due to the picture displayed on the display screen.

Therefore, before connecting the liquid crystal driving driver IC on the transparent electrode, a metal plating layer is formed on the transparent electrode to reduce the resistance value and the connection resistance. Further, not only in the COG type mounting structure described above, but also in the TAB connection type liquid crystal display device, in order to reduce the connection resistance between the transparent electrode and the TAB, a metal plating layer is formed on the transparent electrode. The formation has started.

However, due to the plating process, the sealing agent surrounding the liquid crystal deteriorates with time due to the chemicals used in the plating process and peeling occurs, and air enters the screen, resulting in a defective product. there were. In particular, during plating, the sealing agent on the side immersed in the plating tank was greatly deteriorated.

Also, the sealant surrounding the liquid crystal is U
In the case of the V-curable adhesive, the adhesive itself is also plated, and there is a problem that a plurality of transparent electrodes that drive the liquid crystal are short-circuited and display failure occurs. Therefore, it is an object of the present invention to obtain a liquid crystal display device which is free from a decrease in reliability or a display defect due to a plating process even in a liquid crystal display device formed by a conventional sealant.

[0007]

In order to solve this problem, in a liquid crystal display device comprising two transparent substrates having transparent electrodes formed on the surface thereof, a liquid crystal and a sealant, the liquid crystal is between the two transparent substrates. The part of the sealant that is surrounded by the sealant and is sealed or that surrounds the periphery of the liquid crystal is
It is notched and has a structure that surrounds and seals the liquid crystal by disposing a sealant, and at least a part of the sealant has at least one type of sealant that surrounds the liquid crystal at least twice. Enclose above. The sealant on the outer peripheral side uses a material to which plating does not adhere, and the sealant on the inner peripheral side may be the same material or different materials. Since the sealant on the inner peripheral side is not soaked in the chemical during the plating process, the conventional reliability can be maintained even if the sealant disposed on the outer peripheral side deteriorates with time.

Alternatively, reliability can be secured by further sealing the periphery of the sealant after the electroless plating process in a liquid crystal display device using a sealant to which plating does not adhere in the electroless plating process. Alternatively, reliability may be ensured by reinforcing only the periphery of the portion that is greatly deteriorated.

When a sealing agent to which plating adheres is used on the inner peripheral side, by disposing a sealing agent to which plating does not adhere on the outer peripheral side, a plurality of transparent electrodes overlapping with the sealing agent do not short-circuit. If there is no problem even if the sealing agent that does not overlap with multiple transparent electrodes is plated and reliability is ensured, only the area around the sealing agent that overlaps with multiple transparent electrodes should be covered with the sealing agent that does not adhere to plating. It may be arranged on the side.

Although the outer dimensions are increased by doubling the circumference of the liquid crystal with a sealant, the width of the sealant on the outer peripheral side is made narrower than the width of the sealant on the inner peripheral side in order to make it as small as possible. By doing so, the size of the outer size of the liquid crystal display device is suppressed.

[0011]

The liquid crystal display device configured as described above is a sealant which is not soaked in the chemical used in the electroless plating process in addition to the sealant eroded by the chemical used in the electroless plating process. By separately disposing the sealant, even if the eroded sealant deteriorates, the liquid crystal can be kept sealed by the sealant that is not soaked in the chemical.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a sectional view of Embodiment 1 of the present invention.
Transparent electrodes 2 are formed on the surfaces of glass transparent substrates 1-1 and 1-2.
The liquid crystal 3 is a sealant 4 made of a thermosetting epoxy adhesive between two substrates 1 and 2 formed of ITO.
The outer periphery of the sealant 4 is surrounded by a sealant 5 which is the same adhesive as the sealant 4 with an air layer sandwiched between them. The sealant 5 has a structure in which the air layer on the inner peripheral side is shielded from the outside air. A transparent electrode 2-1 for applying an electric field to the liquid crystal 3 is formed on the surface of the transparent substrate 1-1 so as to be drawn out to the outer peripheral side of the sealant 5 and connected to the liquid crystal drive IC. Further, on the transparent substrate 1-1, a transparent electrode 2-3 connected to the signal input terminal of the liquid crystal drive IC is provided.
1 and the same material are formed at the same time, and the transparent substrate 1-2
Also has a similar transparent electrode pattern. Transparent electrode 2
-3 and the transparent electrode 2-1 pulled out on the outer peripheral side of the sealant 5
A metal plating layer 6 made of nickel and gold was formed on the surface of the. The sealant 5 was eroded and peeled off over time without any adhesion of plating, but the sealant 4 ensured liquid crystal sealing and did not cause problems such as peeling of the seal.

(Second Embodiment) FIG. 2 shows a second embodiment according to the present invention.
FIG. The sealing agent 4 and the sealing agent 5 are formed on the transparent substrate 1-1 side by screen printing with a thermosetting epoxy adhesive, and the sealing agents 4 and 5 are simultaneously cured by aligning with the transparent substrate 1-2 and then thermocompression bonding. did. A liquid crystal injection hole was formed in each of the sealants 4 and 5, and the liquid crystal was injected by immersing the liquid crystal injection hole in the liquid crystal under a vacuum to bring it to atmospheric pressure. At this time, the liquid crystal is also injected between the sealant 4 and the sealant 5. After that, the liquid crystal injection hole was sealed with a UV curable adhesive 7-1.
In this liquid crystal display device, a metal plating layer was formed on the transparent electrodes on the transparent substrates 1-1 and 1-2 in the electroless plating process as in Example 1. As in Example 1, the peripheral sealant 5 was eroded by the chemicals, but the sealant 4 ensured the reliability of liquid crystal sealing.

(Third Embodiment) FIG. 3 shows a third embodiment according to the present invention.
FIG. The structure has been improved so that liquid crystal is not injected between the sealants. Sealant 4 and sealant 5 on the transparent substrate 1-1 side
Was formed from a thermosetting epoxy adhesive by screen printing, and the sealing materials 4 and 5 were simultaneously cured by aligning the transparent substrate 1-2 and heating and pressure bonding. At this time, the air between the sealing agents 4 and 5 escapes from the portion cut at the upper portion of the sealing agent 5. The sealants 4 and 5 are bonded at the liquid crystal injection hole.
The liquid crystal was injected by immersing the liquid crystal injection hole in the liquid crystal under a vacuum and setting the atmospheric pressure. At this time, no liquid crystal was injected between the sealant 4 and the sealant 5. Then liquid crystal injection hole and sealant 5
UV-curable adhesive 7-1, 7-
Sealed with 2. In this liquid crystal display device, a metal plating layer was formed on the transparent electrodes of the transparent substrates 1-1 and 1-2 and the signal input terminal in the same manner as in Example 1 in the electroless plating process. As in Example 1, the peripheral sealant 5 was eroded by the chemicals, but the sealant 4 ensured the reliability of liquid crystal sealing. Since the liquid crystal is not injected between the sealants, the cost can be reduced.

(Fourth Embodiment) FIG. 4 shows a fourth embodiment according to the present invention.
FIG. Measures were taken only on the side of the sealing agent that causes deterioration on the transparent electrode side to be plated. The sealant 4, the sealant 5, and the sealant 8 are formed on the transparent substrate 1-1 side by screen printing with a thermosetting epoxy adhesive, and the transparent substrate 1
-2, the sealants 4, 5 and 8 were simultaneously cured by heating and pressure bonding after alignment. A liquid crystal injection hole was formed in the sealant 8, and the liquid crystal was injected by immersing the liquid crystal injection hole in the liquid crystal under a vacuum to bring it to atmospheric pressure. After that, the liquid crystal injection hole was sealed with a UV curable adhesive 7-1. This liquid crystal display device was subjected to the electroless plating process in the same manner as in Example 1 so that the transparent substrates 1-1 and 1-
A metal plating layer was formed on the transparent electrode above 2. The peripheral sealant 5 was eroded by the chemicals, but the sealant 4 ensured the reliability of liquid crystal sealing. The outer shape of the liquid crystal display device could be made smaller than that in Example 2.

(Fifth Embodiment) FIG. 5 shows a fifth embodiment according to the present invention.
FIG. Measures were taken only around the sealing material that causes deterioration of the transparent electrode to be plated. The sealant 4, the sealant 5, and the sealant 8 are formed on the transparent substrate 1-1 side by screen printing with a thermosetting epoxy adhesive, and the transparent substrate 1-2 is aligned and heated and pressure-bonded to form the sealant 4. 5, 8
Simultaneously cured. A liquid crystal injection hole was formed in the sealant 8, and the liquid crystal was injected by immersing the liquid crystal injection hole in the liquid crystal under a vacuum to bring it to atmospheric pressure. After that, the liquid crystal injection hole was sealed with a UV curable adhesive 7-1. This liquid crystal display device was subjected to the electroless plating process in the same manner as in Example 1 so that the transparent substrates 1-1 and 1-
A metal plating layer was formed on the transparent electrode above 2. The peripheral sealant 5 was eroded by the chemicals, but the sealant 4 ensured the reliability of liquid crystal sealing. As in Example 4, the outer shape of the liquid crystal display device could be reduced.

(Sixth Embodiment) FIG. 6 shows a sixth embodiment according to the present invention.
FIG. Measures were taken only on the side of the sealant that causes deterioration on the transparent electrode side to be plated, and the width of the outer peripheral seal part was reduced. The sealant 4, the sealant 5, and the sealant 8 are formed on the transparent substrate 1-1 side by screen printing with a thermosetting epoxy adhesive, and the transparent substrate 1-2 is aligned and heated and pressure-bonded to form the sealant 4. 5 and 8 were cured simultaneously. Sealing agent 8
A liquid crystal injection hole was formed in, and the liquid crystal was injected by immersing the liquid crystal injection hole in the liquid crystal under a vacuum and bringing it to atmospheric pressure. After that, the liquid crystal injection hole was sealed with a UV curable adhesive 7-1. In this liquid crystal display device, a metal plating layer was formed on the transparent electrodes on the transparent substrates 1-1 and 1-2 in the electroless plating process as in Example 1. The peripheral sealant 5 was eroded by the chemicals, but the sealant 4 ensured the reliability of liquid crystal sealing.
The outer shape of the liquid crystal display device could be made smaller than that of Example 4.

(Embodiment 7) FIG. 7 shows a seventh embodiment according to the present invention.
FIG. A peripheral sealant was placed afterwards. The sealant 4 was formed on the transparent substrate 1-1 side by screen printing with a thermosetting epoxy adhesive, and after aligning with the transparent substrate 1-2, thermocompression bonding was performed to cure the sealant 4. A liquid crystal injection hole was formed in the sealant 4, and the liquid crystal was injected by immersing the liquid crystal injection hole in the liquid crystal under a vacuum to bring it to atmospheric pressure. Then, the liquid crystal injection hole was sealed with a UV curable adhesive. Next, the liquid crystal display device is subjected to the electroless plating process to form the transparent substrates 1-1 and 1-
The metal plating layer 6 was formed on the transparent electrode on 2. After that, the outer periphery of the sealant 4 was coated with a UV curable adhesive 5 having a curing shrinkage of 90% by a dispenser, and was irradiated with ultraviolet rays to be cured. The sealing agent 4 maintained the reliability of liquid crystal sealing by holding the deterioration and the weakening of the adhesive force and the peeling by the contracting force of the UV curable adhesive on the outer periphery.

(Embodiment 8) FIG. 8 shows an embodiment 8 according to the present invention.
FIG. A liquid crystal display device using a UV curable adhesive was plated without a short circuit. The sealant 5 is formed on the transparent substrate 1-1 side by screen printing with a thermosetting epoxy adhesive, and the UV curable adhesive is formed on the transparent substrate 1-2 with a dispenser. 1-1 is applied to the center of the transparent substrate, and two transparent substrates 1-
After aligning 1 and 1-2, they were thermocompression bonded, and the sealant 4 was irradiated with ultraviolet rays to be cured. Next, in the electroless plating process, the metal plating layer 6 was formed on the transparent electrodes on the transparent substrates 1-1 and 1-2 in the same manner as in Example 1. The outer peripheral sealant 5 was not plated but was eroded by the chemical. However, the sealing agent 4 ensured the reliability of liquid crystal sealing. Reliability was obtained by preventing plating on the UV curable adhesive.

[0020]

As described above, according to the present invention, by arranging the seal agent in double or more on the outer or inner circumference of the corroded seal agent and the outer circumference of the plated seal agent,
With the conventional sealant, a reliable liquid crystal display device which does not cause peeling or short circuit due to the electroless plating process has been completed. As a result, COG mounting of a simple matrix liquid crystal display device is possible without deteriorating the display image of the liquid crystal, and an inexpensive liquid crystal display device can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device according to the present invention.

FIG. 2 is a front view of a liquid crystal display device according to the present invention.

FIG. 3 is a front view of a liquid crystal display device according to the present invention.

FIG. 4 is a front view of a liquid crystal display device according to the present invention.

FIG. 5 is a front view of a liquid crystal display device according to the present invention.

FIG. 6 is a front view of a liquid crystal display device according to the present invention.

FIG. 7 is a cross-sectional view of a liquid crystal display device according to the present invention.

FIG. 8 is a cross-sectional view of a liquid crystal display device according to the present invention.

FIG. 9 is a cross-sectional view of a conventional liquid crystal display device.

[Explanation of symbols]

 1-1, 1-2 Transparent substrate 2-1, 2-2, 2-3 Transparent electrode 3 Liquid crystal 4 Inner circumference sealing agent 5 Outer circumference sealing agent 6 Metal plating layer 7-1, 7-2 Sealing agent 8 Sealing agent 9 Liquid crystal drive IC

Claims (5)

[Claims] 1. A liquid crystal display device comprising two transparent substrates having a transparent electrode formed on the surface thereof, a liquid crystal and a sealant, wherein the liquid crystal is applied by the sealant while the transparent electrodes of the two transparent substrates are opposed to each other. A structure in which the periphery of the liquid crystal is surrounded or sealed, or a part of the sealant that surrounds the periphery of the liquid crystal is notched, and the sealant is arranged to surround and seal the periphery of the liquid crystal. Metal plating is formed on the transparent electrode outside the sealing agent, and at least a part of the sealing agent surrounds the liquid crystal at least twice or more with at least one kind of the sealing agent. Liquid crystal display device characterized by. 2. The liquid crystal display device according to claim 1, wherein among the respective sides of the sealing agent, the side on which the metal plating is applied has a double or more double sealing structure. . 3. The sealant double-surrounds the liquid crystal with two kinds of adhesives, the inner adhesive is a UV curable adhesive, and the outer adhesive is a thermosetting adhesive. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is a mold adhesive. 4. The liquid crystal display device according to claim 1, wherein the width of the sealant provided on the inner peripheral side is wider than the width of the sealant provided on the outer peripheral side. 5. A liquid crystal display device, comprising: forming a metal plating on a transparent electrode outside the sealing agent; and disposing a second sealing agent on the outer periphery of at least a part of the sealing agent. Method.