JPH0151167B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides conductivity by forming a metal oxide layer on a gapping agent for a display body made of an insulating material, and forming a metal coating on the gapping agent by electroless plating. It relates to the applied vertical conductive agent for display bodies.

Liquid crystal panels have conventionally been widely used as displays for watches, calculators, and the like.

Recently, there has been a tendency for the display capacity of liquid crystal panels to increase, and the number of upper and lower conductive parts has increased accordingly. Here, FIGS. 1 and 2 are schematic diagrams of the upper and lower conductive parts of a conventional liquid crystal panel.

FIG. 1 shows a case in which soft metal is used to establish vertical conduction between the upper and lower substrates. A hole is made in the upper substrate, and an indium ball 6 made of soft metal is placed in the hole and crushed in order to establish conduction to the lead terminal 5 of the common electrode 3.
In this way, when vertical conduction is established using indium balls, it is often impossible to establish contact between the common electrode 3 and the indium ball 6, and it also takes a lot of man-hours, resulting in poor productivity. The second method is to improve this drawback and reduce the number of man-hours by printing the silver paste 9 on either the upper or lower substrate.
This is the state shown in the figure. However, even in liquid crystal panels in such a state, defects in the upper and lower conductive parts have been a major cause of a decrease in the yield of liquid crystal panels. This is 7
The drying temperature of the sealant shown in Figure 3 and the silver paste shown in Figure 9 are different.Also, liquid crystal panels are usually not manufactured as individual items, but rather are made by bonding two glass plates together, forming the shape shown in Figure 3, and then forming the dotted line. A single liquid crystal panel 10 is manufactured by making a cut in the part and breaking it. As a result, force is applied to the edges of the liquid crystal panel, causing the silver paste outside the sealant to peel off and cause poor vertical continuity. Therefore, when the resin content was increased in order to improve the handling properties of the silver paste, it became difficult to maintain contact between the silver particles within the silver paste, resulting in poor vertical conduction. Furthermore, as the amount of silver particles in the silver paste was increased, the adhesiveness naturally deteriorated. Furthermore, even if the ratio is appropriate, the yield varies greatly depending on humidity, temperature, drying, etc. during production, and it is currently extremely difficult to analyze the causes of this.

Furthermore, when silver paste is used, the diameter of the silver particles is not constant, and the diameter of the large particles is generally 7μ or more. For this reason, the gap thickness
It was difficult to mass produce 5μm liquid crystal panels. FIG. 4 shows this state. 11 is a silver particle, 1
2 is the adhesive resin in the silver paste.

Therefore, a top-bottom conductive agent was devised in which conductivity was imparted by applying electroless plating to the gapping agent used to ensure the gap in particle size in liquid crystal panels. However, since the electroless plating film was formed directly on the insulating material, the adhesion between the plating film and the insulating material was poor, and when the gapping agent with the plating film was dispersed in the adhesive, the plating film was likely to peel off, resulting in poor dispersion. The method required careful attention, and the reliability of vertical conduction tended to be insufficient. Furthermore, there were some areas where the plating film was not formed, resulting in a lack of reliability. Here, the present inventor has discovered a method of forming an electroless plating film on an insulator with good adhesion and uniformity by forming a metal oxide layer on the insulator and then forming an electroless plating film.

Therefore, in order to improve these drawbacks, the present invention forms a metal oxide layer on the gapping agent used to ensure the gap in the particle size of the liquid crystal panel, and then performs electroless plating on the gapping agent. It is characterized by the use of a vertical conductive agent that imparts conductivity.

Examples of the vertical conductive agent include glass fiber, alumina, and inorganic glass beads, and when this agent is used, contact failures in vertical conduction due to gaps in the liquid crystal panel are eliminated. This state is shown in FIG.

Furthermore, as the metal oxide layer formed on the insulating material, one or a mixed film of two or more of SnO ₂ , Sb ₂ O ₃ , TiO ₂ , In ₂ O ₃ , etc. can be electrolessly plated. It is suitable for uniformly applying materials with good adhesion, but is not limited to these.

Next, a method for manufacturing the vertical conductive agent for display panels according to the present invention will be outlined.

An inorganic gapping agent such as glass fiber, alumina, or inorganic glass beads is dispersed in heated water to create a heated suspension. Next, dissolve one or more metal salts such as stannic chloride, antimony chloride, titanium chloride, indium chloride, etc. in a low boiling point solvent such as methanol or ethanol, and add this to the heated suspension. When the alcohol and alcohol come into contact with heated water, they instantly evaporate and hydrolysis occurs, forming a uniform metal oxide layer on the inorganic gapping agent. By washing this three times and baking it in air at 400°C to 500°C, a metal oxide film is formed on the insulator with good adhesion. Next, in order to perform electroless plating on this, the following electroless pretreatment process is usually used.

(1) Alkaline degreasing (2) Acid neutralization (3) Sensitizing in SnCl ₂ solution (4) Activating in PdCl ₂ solution. Sensitizing is a process in which, for example, Sn ²⁺ ions are adsorbed onto the surface of an insulating material, and activating is a process in which, for example, a reaction of Sn ²⁺ + Pd ²⁺ → Sn ⁴ + Pd ⁰ occurs on the surface of an insulating material, and Pd ⁰ This is a process in which the metal is used as a catalyst nucleus for electroless plating.

After performing the electroless plating pretreatment step, metallization can be performed by immersing the product in an electroless plating bath that has been prepared and heated according to a predetermined method.

Electroless plating baths include Au, Ni, Cu, Ag,
There are plating baths such as Co and Sn that can be used as upper and lower conductive agents, but the adhesion of the plating film is limited to Ni.
Therefore, the electroless nickel bath is the best for metallizing insulating materials.

The thickness of the metal oxide layer and plating film mentioned above should be determined when using a gapping agent for liquid crystal panels.
200 Å to 5000 Å is good. If it is less than 200 Å, it is not practical because there will be parts of the gapping agent where no plating film is formed and the resistance will become large. If the thickness exceeds 5000 Å, there will be a difference of 1 μm or more between the upper and lower conductive parts and the liquid crystal gap thickness, and the liquid crystal layer will become non-uniform, resulting in uneven color due to changes in drive voltage or interference colors.

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

The thus metalized insulating material is added to the adhesive and uniformly dispersed.

As the adhesive, epoxy resin, acrylic resin, etc. were used.

The appropriate proportion of the metalized insulating material in the above adhesive is 0.1wt% to 30wt%, and 0.1wt%
% or less, the resistance of the conductive portion tends to increase or fluctuate. Furthermore, if the content exceeds 30 wt%, problems with adhesion tend to occur. The dispersion state of the gapping agent is preferably 5 particles/mm ² to 500 particles/mm ² at least in the upper and lower conductive parts of the liquid crystal panel. upper limit,
The lower limit value is determined for the same reason as above. of course,
These values differ somewhat depending on the diameter of the insulating material.

The thus produced vertical conductive agent was applied to the vertical conductive portions of the liquid crystal panel by printing and incorporated into the liquid crystal panel.

Glass is usually used for the substrate of liquid crystal panels, but transparent electrodes (SnO ₂ ,
In ₂ O ₃ etc.) may be patterned. In the case of plastic film, the contact area between the upper and lower conductive materials may dent due to the pressure applied during assembly.
This increases the contact area with the upper and lower conductive members and increases reliability.

Next, a detailed explanation will be given using examples.

Example 1 10g of glass fiber powder with a diameter of 5μm is added to 1 part of water.
The mixture was heated to 90°C and stirred to prepare a uniformly dispersed heated suspension. A solution consisting of 80 g of SnCl ₄ dissolved in 300 c.c. of ethanol is slowly injected into this heated suspension over 2 hours to deposit a coating layer of SnO ₂ on the glass fiber,
3. Separately, it was washed and fired at 500°C for 1 hour.

Next, these particles were dispersed in a mixed solution of 1 g of SnCl ₂ /, 1 c.c. of HCl, and after filtering and washing with water, these particles were placed in a redosumer manufactured by Kanigen Co., Ltd., which was prepared using a prescribed method. Disperse, filter,
Washed with water.

Then, it was dispersed for 6 minutes in a Kanigen S-680 solution (45°C) prepared by a predetermined method.
Filtered and washed with water. This resulted in a 3500 Å nickel-phosphorus plating on the glass fiber. Disperse this in epoxy resin at a ratio of 25wt%,
When used as a conductor between the upper and lower sides of a borosilicate glass liquid crystal panel, the resistance value was 9KΩ (resistance value was measured through Nesa glass). Further, even when a predetermined accelerated test was performed, there was no change in the resistance value.

Example 2 A 7μm SnO ₂ film was formed in the same way as Example 1.
2000Å nickel on glass fiber particles
After phosphor plating, a 500 Å nickel-phosphorus layer was replaced with gold using an Atmex gold plating bath manufactured by Nippon Engelhard. In other words, a nickel-phosphorous layer was formed at 1500 Å, and a gold layer was formed at 500 Å above it.

When this was dispersed in epoxy resin at 5wt% and used as a vertical conduction agent for a liquid crystal panel, the resistance value for vertical conduction was 8KΩ. Further, even when a predetermined acceleration test was performed, there was no change in resistance.

Example 3 The 7 μm glass fiber particles metalized in Example 2 were dispersed at 15 wt % in a UV-curable acrylic resin and used as a vertical conductor in a liquid crystal panel made of polyethylene film. The resistance value for vertical conduction was 17KΩ, and there was no change in resistance value even during accelerated tests.

Example 4 2 wt % of the 7 μm glass fiber particles metallized in Example 2 were dispersed in a silver paste and used as an upper and lower conductive agent for a liquid crystal panel. The resistance value was slightly lower than that of silver paste, and there was no change in resistance during accelerated testing.

Example 5 Similar to Example 4, glass fiber particles were
Similar results were obtained when it was dispersed in a 10wt% silver paste and used as a conductive agent between the upper and lower sides of a liquid crystal panel.

Example 6 After forming a SnO ₂ film on 10 μm alumina particles in the same manner as in Example 1, nickel-phosphorus electroless plating was performed to a thickness of 3000 Å, and the same test as in Example 1 was conducted. The value was 10KΩ (the resistance value was measured by changing the Nesa glass), and the resistance value did not change even after performing the specified acceleration test.

Example 7 10g of glass fiber powder with a diameter of 7μm is added to 1 part of water.
In addition, the mixture was heated and stirred at 90°C to prepare a uniformly dispersed heated suspension. Ethanol to this heated suspension
A solution consisting of 30 g of TiCl ₄ dissolved in 300 c.c. was slowly injected over 2 hours to deposit a coating layer of TiO ₂ on the glass fiber,
It was filtered, washed, and fired at 500°C for 1 hour.

When this was subjected to electroless plating in the same manner as in Example 1, the same results as in Example 1 were obtained.

When the vertical conductive agents of Examples 1 to 7 were used, the defective vertical conductivity was reduced to 1/20 compared to the case where the conventional vertical conductive agents were used.

As described above, according to the present invention, since the metal oxide layer is provided on the surface of the gapping agent, the adhesion between the electroless nickel plating film and the gapping agent made of an insulating material is significantly improved. Moreover, since the mixing ratio with the adhesive is 0.1 wt% to 30 wt%, stable adhesiveness with small variations in resistance in the upper and lower conductive parts can be obtained.

[Brief explanation of drawings]

Figure 1: Cross-sectional view of conventional liquid crystal panel 1, 2: Upper and lower substrates, 3, 4: Upper and lower transparent electrodes,
5: Conductive terminal from the upper electrode, 6... Soft metal (indium ball), 7... Seal part containing gapping agent,
8...Liquid crystal, Figure 2...Cross-sectional view of other conventional liquid crystal panels 9: Vertical conduction agent, Figure 3...Substrate plan view during the process of a general liquid crystal panel 10: Single liquid crystal panel, Figure 4...Vertical conduction 11... Silver particles, 12: Adhesive resin in silver paste, Fig. 5... Cross-sectional view of upper and lower conductive parts (present invention: glass fiber) 13... Glass fiber, 14... Adhesive material.

Claims (1)

[Claims] 1 A metal oxide layer is formed on the surface of a gap agent made of an insulating material to ensure a gap between a pair of substrates, and an electroless nickel plating film is further formed on the metal oxide layer, and the gap is A vertical conductive agent for a display panel, characterized in that an adhesive is dispersed in an adhesive in a range of 0.1wt% to 30wt%.