JPH06102522A - Display panel - Google Patents

Abstract

PURPOSE:To provide the display panel which does not generate the conduction defects of conductive parts between upper and lower panels. CONSTITUTION:Conductive materials formed with metallic films 13a are used on the outside surfaces of glass fibers 13 in the junctures of the section of the junctures of electrodes 3 of an upper substrate 1 and lead electrodes 5 of a lower substrate of the liquid crystal panels and are adhered by using conductive adhesives 14. The conductive materials have the diameter of the size substantially equal to the gap spacing of the upper and lower substrates and are, therefore, commonly usable as gap materials.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive material obtained by metallizing a gap material for a display body made of an insulating material, and more specifically, a display body having a bar-shaped upper and lower conductive material metallized by electroless plating. It's about panels.

[0002]

2. Description of the Related Art Liquid crystal panels are now widely used as display bodies for timepieces, calculators, televisions, measuring instruments and the like. Recently, the display capacity of liquid crystal panels tends to increase.

Here, FIG. 3 is a schematic view of a vertical conducting material of a conventional liquid crystal panel. In the figure, 1 is an upper substrate, 2 is a lower substrate, 3 is a common electrode, 4 is a lower electrode, 5 is a lead terminal, 6
Is an indium ball, and 8 is a liquid crystal.

FIG. 3 shows a case where a soft metal is used to establish vertical conduction between the upper and lower substrates 1 and 2. A hole is made in the upper substrate 1, and in order to establish conduction from the common electrode 3 to the lead terminal 5, an indium ball 6 which is a soft metal is put in the hole and is crushed. As described above, when the upper and lower substrates are electrically connected by the indium balls 6, the common electrode 3 and the indium balls 6 often cannot be contacted, and the number of steps is increased, resulting in poor productivity.

FIG. 4 shows an improvement of this defect, in which a conductive adhesive is used. In the figure, the same parts as those in FIG. 7 is a sealant,
9 is a silver paste. The number of steps is reduced by printing the sealing material 7 and the silver paste 9 on the outside thereof on one of the upper and lower substrates 1 and 2. However, a liquid crystal panel using a conductive adhesive also causes a conduction failure in the vertical conduction portion, which is a major cause of lowering the yield of the liquid crystal panel. This is because the sealing material 7 and the silver paste 9 have different drying temperatures. Also, a normal liquid crystal panel is
The liquid crystal panel 10 is not manufactured individually, but is manufactured by bonding two glass plates to each other and forming a shape as shown in FIG. For this reason, a force is applied to the end portion of the liquid crystal panel, and the silver paste on the outside of the sealing material is peeled off, which causes a conduction failure in the vertical conduction portion.

Therefore, if the resin content is increased in order to increase the adhesiveness of the silver paste, it becomes difficult for the silver particles to come into contact with each other within the silver paste, which causes poor conduction. In addition, when the amount of silver particles in the silver paste is large, the adhesiveness naturally deteriorates. Further, even if the ratio is appropriate, the yield greatly varies depending on the humidity, the temperature during the manufacturing, the temperature during the drying, etc., and it is currently difficult to analyze the cause.

Further, when the silver paste is used, as shown in FIG. 6, since the diameter of the silver particles 11 mixed in the adhesive 12 is not constant, it is possible to set the gap distance between the upper and lower substrates 1 and 2. However, there is also a problem that it is necessary to consider separately disposing a spacer or the like.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to provide a display panel which does not cause vertical conduction failure.

[0009]

The present invention has a pair of substrates in which an electro-optical material is sandwiched, and the pair of substrates are opposed to each other with a constant gap space therebetween. In a display panel having a vertical conducting portion between them, the vertical conducting portion is made of a conductive adhesive and a conductive material made of an insulating material having a metal coating formed on the outer surface, and the metal coating is formed. In addition, the diameter of the rod-shaped conductive material in at least one direction is substantially equal to the gap distance in the bonded state, and the upper and lower panels are electrically connected.

[0010]

According to the present invention, the vertical conducting portion is formed of a conductive adhesive and a conductive material made of an insulating material having a metal coating formed on the outer surface thereof, thereby forming a vertical conducting portion having good conduction characteristics. it can. In addition, since the diameter of the conductive material in at least one direction is substantially equal to the gap distance in the bonded state, the conductive material doubles as a spacer and more reliably contacts the electrode. Therefore, the conduction resistance can be reduced.

[0011]

1 is a sectional view of a conducting portion in an embodiment of the display panel of the present invention. In the figure, the same parts as those in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 13 is a metallized glass fiber, and 14 is an adhesive.
The conductive material is not limited to the glass fiber 13 provided with the conductive film 13a, and alumina, inorganic glass beads, or the like can be used. In this embodiment, the glass fiber is sandwiched between the upper and lower substrates, and the upper and lower panels are electrically connected to each other to eliminate the contact failure. The height of the conductive material is equal to the distance between the upper and lower electrodes 1, 2. As the adhesive material 14, a conductive adhesive can be used. The conductive particles contained in the conductive adhesive are preferably fine particles. By using a conductive adhesive as the adhesive, the conduction resistance can be further reduced. It is also possible to use a synthetic resin adhesive such as epoxy if the conduction resistance is sacrificed to some extent.

FIG. 2 is a cross-sectional view of a conducting portion of an embodiment of a display panel using a synthetic resin having a conductive film on its surface as a conductive material and having elasticity. In the figure, the same parts as those in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted. Reference numeral 15 is a metallized plastic ball, and 16 is an adhesive. A conductive adhesive can also be used as the adhesive 16. Examples of synthetic resin materials include plastic balls and plastic fibers. When this is used, the plastic ball or plastic fiber preferably has the same diameter as the gap thickness of the liquid crystal panel or up to twice the diameter. This is an upper and lower conductive material for the purpose of eliminating poor contact for the same reason as described above, but if the diameter of the plastic ball or plastic fiber is larger than the gap of the liquid crystal panel, even if the gap thickness of the liquid crystal panel changes, Since the material is rich in elasticity, the metallized conductive material changes, the conductive portion is strong, and the conductive film 15a comes into planar contact, so that the contact failure is eliminated.

If the diameter of the plastic ball or the plastic fiber exceeds twice the gap thickness of the liquid crystal panel, the conductive material is compressed to 1/2 or less when the panel is assembled, so that the conductive film 15a is formed. It is easy for cracks to occur, which in turn causes poor conduction between the upper and lower electrodes. Preferably, the plastic ball diameter is about 1.1 to 1.3 times the gap thickness of the liquid crystal panel.

Next, a method of manufacturing the conductive material of the present invention will be described. In order to plate the above insulating material, the following electroless pretreatment process is usually performed. Alkali degreasing acid neutralization SnCl ₂ solution sensitizing PdCl ₂ solution activating. Sensitizing is a step of adsorbing, for example, Sn ²⁺ ions on the surface of an insulating material, and activating causes, for example, a reaction of Sn ²⁺ + Pd ²⁺ → Sn ⁴ + Pd ⁰ to occur on the surface of the insulating material, and Pd ^This is a step in which ⁰ is used as a catalyst core for electroless plating.

After performing the pretreatment step of electroless plating, metalizing can be carried out by immersing in a building bath or a heated electroless plating bath according to a predetermined method. Electroless plating baths include Au, Ni, Cu, Ag, Co, Sn
There is a plating bath such as, and any of them can be used as a conductive film in a conductive material, but the adhesion of the plating film is Ni.
Therefore, it can be said that the electroless nickel bath is the best for metallizing the insulating material.

When used as a gap material for a liquid crystal panel, the plating film thickness is preferably 200Å to 5000Å. Two
If it is less than 00Å, it is not practical because the gap agent has a portion where the plating film is not formed or the resistance increases. If the thickness is 5000 Å or more, the gap between the upper and lower conducting parts and the liquid crystal gap is 1 μm or more, the liquid crystal layer becomes non-uniform, and the driving voltage changes or the interference color causes uneven color.

When metalizing the above-mentioned plastic balls and plastic fibers, the plating film thickness is preferably 200Å-4 μm. 2 for the same reason as above
A plating thickness of 00 Å or less is not suitable, and if a plating film having a thickness of 4 μm or more is formed, cracks are likely to occur in the plating layer during panel assembly, which is likely to cause conduction failure. Further, if the plating film is formed thicker than this, it becomes difficult to control the gap of the liquid crystal panel.

When a nickel film or the like is formed on the insulating material and the resistance value is large, a noble metal film having good electrical conductivity such as electroless silver plating or electroless gold plating is formed on the surface of nickel or the like. good. The thickness of the noble metal electroless plating is preferably 50Å to 1 μm.

Thus, when the metal coating was formed by electroless plating, a uniform film thickness could be formed on the surfaces of all insulating members.

A conductive material which is an insulating substance metallized in this manner can be added to an adhesive and uniformly dispersed to be used as a conductive material. As the adhesive, a conductive adhesive such as silver paste or carbon paste, epoxy resin, acrylic resin or the like can be used.

A suitable ratio of the conductive material mixed into the adhesive is 0.1 wt% to 30 wt%, which is 0.1 w.
When it is t% or less, the resistance of the conductive portion is likely to increase or vary. Further, if it is 30 wt% or more, the adhesiveness tends to be a problem. Moreover, the dispersion state of the gap agent, 5 Ke / mm ² to 500 Ke / mm ² is good in at least upper and lower conductive portions of the liquid crystal panel. The upper and lower limits are for the same reason as above. Of course, these values are slightly different depending on the diameter of the insulating material and the adhesive.

The conductive material produced in this manner is attached to the upper and lower conductive parts of the liquid crystal panel by printing and is incorporated in the liquid crystal panel. Glass is usually used for the substrate of the liquid crystal panel, but a plastic film on which transparent electrodes (SnO ₂ , In ₂ O _3, etc.) are patterned may be used. In the case of a plastic film, the portion in contact with the conductive material is dented by the pressure applied during assembly, thereby increasing the contact area with the conductive material and increasing the reliability.

Next, the embodiment will be described in more detail. --Example 1-- Glass fiber particles having a diameter of 5 .mu.m were immersed in a 10N sodium hydroxide solution for 5 minutes, washed with water and neutralized. These particles were filtered in each step with a microfilter having a pore size of 1 μm. Next, 1g of SnCl ₂
/ L, HCl, these particles were dispersed in a mixed solution of 1 cc / l, filtered, washed with water, and then dispersed in a Kanigen Red Schumer made by a predetermined method, and filtered. Washed with water. Then, in a Kanigen S-680 solution bath prepared by a predetermined method, 45 ° C
Was dispersed for 6 minutes, filtered, and washed with water. This resulted in 3500Å nickel-phosphorus plating on the glass fiber. When this was dispersed in an epoxy resin at a ratio of 25 wt% and used as a vertical conducting material of a liquid crystal panel of borosilicate glass, the resistance value was 9 kΩ (the resistance value was measured through Nesa glass). Further, the resistance value did not change even when the predetermined acceleration test was performed.

--Example 2-- As in Example 1, 2 was formed on a glass fiber particle having a diameter of 7 .mu.m.
After applying 000Å nickel-phosphorus plating, 500Å with Atmex gold plating bath manufactured by Nippon Engelhard
Of the nickel-phosphorus layer was replaced with gold and plated. That is 15
A nickel-phosphorus layer was formed on 00Å, and a gold layer was formed on 500Å as an upper layer. When this was dispersed in an epoxy resin in an amount of 5 wt% and used as a vertical conducting material for a liquid crystal panel, the vertical conducting resistance value was 8 kΩ. In addition, the resistance did not change even after the predetermined acceleration test.

--Example 3-- The glass fiber particles having a diameter of 7 .mu.m metallized in Example 2 are dispersed in a UV curable (ultraviolet curable) acrylic resin in an amount of 15 wt% to form a polyethylene film as an upper and lower conducting material. Used for liquid crystal panel. The resistance value of the vertical conduction was 7 kΩ, and there was no change in the resistance value during the acceleration test.

--Example 4-- 2 wt% of the glass fiber particles having a diameter of 7 .mu.m metallized in Example 2 were dispersed in a silver paste and used as a vertical conducting material for a liquid crystal panel. The resistance value was slightly lower than that of the silver paste alone, and there was no change in resistance in the accelerated test.

--- Example 5-- Similar to Example 4, 10 wt% of glass fiber particles,
When dispersed in a silver paste and used as a vertical conducting material for a liquid crystal panel, similar results were obtained.

Example 6--Aluminum particles of 10 μm were subjected to nickel-phosphorus electroless plating in the same manner as in Example 1 to a thickness of 3000 Å,
In the same manner as in Example 2, 600 Å electroless gold plating was performed. When this was dispersed in an epoxy resin in an amount of 10 wt% and used as a vertical conducting material for a liquid crystal panel, the resistance value was 8 kΩ, and the value did not change even in the acceleration test.

Example 7 A styrene ball having a diameter of 12 μm was dipped in a chromic acid mixed solution for 5 minutes, filtered through a microfilter having a hole diameter of 2 μm, and thoroughly washed with water. Next, SnCl ₂ is 1 g / l, HC
These particles were dispersed in a mixed solution of 1 cc / l, filtered, washed with water, and then dispersed in a Kanigen Red Schumer made by a predetermined method, filtered, and washed with water. Then, it was dispersed for 6 minutes in an S-680 solution (45 ° C.) manufactured by Kanigen Co., which was bathed by a predetermined method, filtered, and washed with water. This gives 350 on the styrene balls.
Nickel-phosphorus plating of 0Å was completed. When 20 wt% was dispersed in an epoxy resin and used as a vertical conducting material of a liquid crystal panel having a gap thickness of 10 μm, the resistance value of the vertical conducting portion was 8 kΩ. Further, the resistance value did not change even when the predetermined acceleration test was performed.

--Example 8-- Styrene balls metallized in Example 7 were dispersed in an ultraviolet curable acrylic resin at 10 wt% to give Example 1.
A liquid crystal panel having a gap thickness of 10 μm was prepared in the same manner as in (1).
The resistance value of the upper and lower conducting parts of the liquid crystal panel was 9 kΩ, and the value did not change even after the predetermined acceleration test.

--Example 9 --- As in Example 1, nylon balls having a diameter of 10 .mu.m were used and 2
A 500-Å nickel-phosphorus plating was performed. afterwards,
Substitution gold plating of 500 Å was applied with Atomex electroless gold plating solution manufactured by Nippon Engelhardt. When this was dispersed in epoxy resin at 5 wt% and used as a vertical conducting material for a liquid crystal panel having a gap thickness of 10 μm, the resistance value of the vertical conducting portion was 6 kΩ, and the value did not change even after a predetermined acceleration test. There wasn't.

--Example 10-- As in Example 3, 2 g of a styrene ball having a diameter of 10 .mu.m was used.
000 Å electroless nickel plating and 600 Å electroless gold plating were applied and dispersed in silver paste at 3 wt% to obtain a vertical conducting material for a liquid crystal panel having a gap thickness of 7 μm. The resistance value of the upper and lower conducting parts was 6 kΩ, and the value did not change even after the predetermined acceleration test.

Example 11-The styrene balls metallized in Example 4 were dispersed in an ultraviolet curable acrylic resin in an amount of 10 wt% and used as a vertical conducting material for a liquid crystal panel having a gap thickness of 10 μm. Has a resistance value of 8 kΩ, which has not changed even after the predetermined acceleration test.

Example 12-In a substrate made of quartz glass for a liquid crystal panel, after the transparent electrode was patterned in a predetermined manner, the upper and lower conducting portions were masked with a resist material, and then sputtering was performed to insulate other conducting portions. An apparatus formed a 4000 Å SiO ₂ film. Next, after the resist material was peeled off, 15 wt% of the vertical conducting material of Examples 1 to 6 was dispersed in the epoxy resin used as the sealing material and used as the sealing material. As a result, a liquid crystal panel having a simple structure in which the vertical conduction portion and the seal portion are integrated was completed. This has reduced the printing man-hours and has led to an improvement in yield. In addition, the characteristics did not change at all as compared with the liquid crystal panel in which the seal portion and the vertical conduction portion were separated.

When the vertical conducting materials of Examples 1 to 12 were used, the vertical conducting defects were reduced to 1/10 as compared with the conventional vertical conducting materials.

In the above description, since most display panels are liquid crystal panels at present, the liquid crystal panel is mainly described. However, the present invention is applicable to an electrochromic panel, an electroluminescence panel, and the like. It goes without saying that it can be applied to various display bodies.

[0037]

As described above, according to the present invention,
Since a conductive adhesive and a conductive material having a metal coating formed on the surface of the insulating member and having a diameter in at least one direction equal to the gap distance are used, a pair of metal coating is directly applied. The upper and lower electrodes formed on the substrate can be connected, and the conductive adhesive intervenes to prevent conduction failure between the upper and lower panels. Therefore, since the specific resistance in the upper and lower conducting portions becomes very small, the display characteristics of the display panel are improved without lowering the effective voltage, for example.

Further, when the diameter of the conductive material before being arranged in the display panel is made equal to the gap interval,
The conductive material has a function of so-called gap material, which serves to conduct electricity and to maintain a gap distance between the pair of substrates.

If the diameter of the elastic conductive material before the disposition in the display panel is larger than the gap distance, the conductive material is pressed to the gap distance by the elasticity and is simultaneously deformed. Therefore, the diameter of the conductive material in one direction becomes substantially equal to the gap distance. At this time,
Since there is surface contact with conductive parts such as electrodes formed on the upper and lower panels, there is an effect that more reliable conductivity can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conducting portion in a display panel of the present invention.

FIG. 2 is a cross-sectional view of a conducting portion in another embodiment of the display panel of the present invention.

FIG. 3 is a schematic view of a vertical conduction member of a conventional liquid crystal panel.

FIG. 4 is a schematic view of a vertical conduction member of another conventional liquid crystal panel.

FIG. 5 is an explanatory diagram of a manufacturing process of a liquid crystal panel.

FIG. 6 is a cross-sectional view of a conductive portion using a conventional silver paste.

[Explanation of symbols]

 1 Upper Substrate 2 Lower Substrate 3 Common Electrode 4 Lower Electrode 5 Lead Terminal 6 Indium Ball 7 Sealant 8 Liquid Crystal 9 Silver Paste 13 Metallized Glass Fiber 14 Adhesive 15 Metallized Plastic Ball 16 Adhesive

Claims (1)

[Claims] A display body panel having a pair of substrates sandwiching an electro-optical material, wherein the pair of substrates are opposed to each other with a constant gap interval, and a vertical conduction portion is provided between the substrates. The upper and lower conducting portions are made of a conductive material made of an electrically conductive adhesive and an insulating material having a metal coating formed on the outer surface, and the rod-shaped conductive material having the metal coating has a diameter in at least one direction, In a bonded state, a display panel having a size substantially equal to the gap interval and conducting electrical connection between the upper and lower panels.