JP3234141B2 - Discharge treatment equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge processing apparatus used for manufacturing a liquid crystal element having a large area, and more particularly to a discharge processing apparatus for modifying a surface of a substrate.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal element (hereinafter referred to as a "liquid crystal panel") has a pair of substrates arranged in parallel, and a liquid crystal is sandwiched between the substrates.
Further, a polarizing film was directly adhered to the outer surfaces of these substrates (hereinafter referred to as “panel surfaces”).

In this liquid crystal panel, a pair of substrates processed through various processes are bonded (substrate bonding process), liquid crystal is injected into a gap between the substrates (liquid crystal injection process), and a polarizing film is formed on the panel surface. (Polarizing film sticking step).

Note that various stains are attached to the panel surface before the polarizing film is attached, and such stains weaken the adhesive strength of the polarizing film. Washing was taking place.

[0005]

However, dirt on the panel surface has not been completely removed only by such simple cleaning. In particular, in the case where a panel surface is contaminated by the processing agent, for example, a processing agent containing a silicone resin is used in the manufacturing process, and the dirt is burned by heat applied in the manufacturing process. ,
The stains are stably chemically adsorbed on the panel surface and cannot be removed by simple washing as in the past. And
Such dirt weakens the adhesive strength of the polarizing film in order to direct the water-repellent groups outward.

On the other hand, the attached polarizing film shrinks with a change in temperature, but the area of the polarizing film (ie,
The larger the area of the liquid crystal panel), the larger the amount of contraction.

In recent years, a large-area liquid crystal panel capable of displaying a large amount of information has been receiving attention. In such a liquid crystal panel, the amount of heat shrinkage of the polarizing film due to a temperature change is large. However, there is a problem that the polarizing film is easily peeled off in combination with the decrease in the adhesive strength due to the above-mentioned stain.

[0008]

Accordingly, an object of the present invention is to provide a discharge treatment apparatus that improves the wettability of the surface of a substrate and increases the adhesive strength of a polarizing film.

Another object of the present invention is to provide a discharge processing apparatus for preventing a liquid crystal element from being destroyed when performing a discharge processing.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a liquid crystal element holding means for holding a liquid crystal element, an electrode arranged to face the liquid crystal element, and A power supply connected to the electrode and applying a high voltage to the electrode; and a covering means formed of a conductor and grounded and arranged to cover a terminal electrode portion formed on the liquid crystal element. provided, and, based on applying a high voltage to the electrode, the corona discharge treatment is performed with respect to the surface of the liquid crystal element held by the liquid crystal element holding means, said
High voltage from the electrode is applied to the terminal electrode by the coating means.
The voltage is not applied to the portion . Here, it is preferable that the coating means is made of metal.

[0012]

In addition, based on the above configuration, when the power supply is turned on and a high voltage is applied to the electrodes while the covering means is arranged so as to cover the terminal electrode portion and the liquid crystal element is held by the liquid crystal element holding means, Corona discharge treatment is performed on the surface of the liquid crystal element to prevent a high voltage from being applied to the terminal electrodes.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

First, an embodiment of the present invention will be described with reference to FIG.
5 will be described with reference to FIG.

As is known, a liquid crystal panel (liquid crystal element) includes a pair of substrates arranged in parallel, and a scanning electrode and an information electrode are formed on the inner surface of each substrate. These electrodes are exposed at the edge of the substrate to form a terminal electrode portion 8 (see FIG. 3). A liquid crystal is sandwiched between the pair of substrates, and is configured to display various information based on switching of the liquid crystal by applying various signals to scanning electrodes and information electrodes. .

Next, a method of manufacturing a liquid crystal panel will be briefly described.

In manufacturing a liquid crystal panel, first, an ITO film is formed on the inner surface of the substrate, and the ITO film is patterned to form scanning electrodes and information electrodes of a predetermined shape. Next, so as to cover these scanning electrodes and information electrodes,
An insulating film and an orientation control film are formed. (Substrate Bonding Step) Further, a spacer is scattered and a sealing material is applied to the substrate on which these thin films are formed, and the pair of substrates is bonded. (Liquid Crystal Injection Step) Next, liquid crystal is injected into the gap between the substrates bonded in the substrate bonding step. Thereby, a liquid crystal panel is manufactured. (Discharge treatment step) Next, the liquid crystal panel manufactured as described above is set in a discharge treatment device 1 as shown in FIG. 1, and a corona discharge treatment is performed on the panel surface (see reference numeral Pa in FIG. 3). The surface energy of the panel surface Pa is set to 40 dyn / cm or more, and the contact angle of water is set to 60 ° or less. here,
The discharge processing device 1 will be described.

The discharge processing device 1 has a liquid crystal panel P mounted thereon.
A metal table (liquid crystal element holding means) 2 for holding is provided, and a metal moving stage (liquid crystal element holding means) 3 is mounted on the upper surface of the table 2. The moving stage 3 is provided with a handle 3a as shown, and is configured to be moved by automatically or manually operating the handle 3a.

On the upper surface of the moving stage 3, a panel protection tray (covering means) 5 and a liquid crystal panel P accommodated in the panel protection tray 5 are placed.
As shown in FIGS. 2 and 3, the panel protection tray 5 is formed by a cover plate 6 and a base plate 7 so as to be openable and closable. The cover plate 6 has an opening 6a. The terminal electrode portion 8 of the liquid crystal panel P is covered, and the panel surface Pa is exposed to the outside. The table 2 and the moving stage 3 are grounded, and the panel protection tray 5 is formed of a metal plate which is a conductor and is grounded via the moving stage 3.

On the other hand, a pair of insulating holders 10 are placed on the upper surface of the table 2 so as to sandwich the moving stage 3.
a and 10b are attached (see FIG. 1), and a quartz electrode 11 is attached to these insulating holders 10a and 10b. Then, as shown in detail in FIG.
The quartz electrode 11 is arranged so as to face the liquid crystal panel P with a certain distance (hereinafter, referred to as “discharge gap”) d. In the present embodiment, the thickness of panel P is 2.0 mm, and the discharge gap is d = 1.
It is set to 0 mm. Therefore, when there is no load.
This results in a gap of 0 mm.

On the other hand, the quartz electrode 11 is connected to a high-frequency power source (A
GI-020) 13 and the quartz electrode 1
1 is applied with a high voltage. In the present embodiment, the output of the high-frequency power supply 13 is 150 to
The oscillation frequency is about 40 to 22 kHz, and the discharge voltage is 20 kV.

Next, the details of the work in the discharge treatment step will be described in detail.

In performing the discharge process, first, the liquid crystal panel P stored in the panel protection tray 5 is placed at a predetermined position on the moving stage 3. In this state, the liquid crystal panel P is covered with the terminal electrode portions 8 and the panel surface P
a is exposed to the outside.

Next, the main power switch of the high frequency power supply 13 is turned on, and the output is set in the range of 150 to 500 W.

In this state, when an operation switch (not shown) is turned on and a high voltage is applied to the quartz electrode 11, a corona discharge occurs near the discharge gap, and ozone O ₃ is generated. In addition, oxygen radicals (free radicals) O. are generated based on the discharge energy of the ozone O ₃ .

By the way, the panel surface Pa is contaminated with silicon oil or the like in the process up to the electric discharge process, and the oil is fixed by dimethylsiloxane under the influence of the heat treatment applied to the manufacturing process. It has become.

However, in this discharge treatment step, the above-mentioned oxygen radical O. oxidizes the CH ₃ group and the like on the panel surface Pa to form carbonyl C ＝ O, and the silanol (−)
OH group) to improve the wettability of the panel surface Pa. In the present step, the entire stage of the panel P is subjected to the discharge treatment by moving the moving stage 3, so that the wettability of the entire panel surface is improved. Here, the required time is
5 to 6 seconds per panel. (Polarizing Film Pasting Step) Further, a polarizing film is pasted on the panel surface Pa treated in the electric discharge treatment step.

Next, effects of the present embodiment will be described.

According to the present embodiment, the —OH group is generated by the discharge treatment step, and the wettability of the panel surface Pa is improved. As a result, the adhesive strength of the polarizing film is improved, and the polarizing film is less likely to be peeled off in a large-sized liquid crystal panel even when subjected to heat shrinkage. Further, the durability with respect to the adhesion of the polarizing film is improved.

The present inventor conducted experiments to confirm the above-mentioned effects. Hereinafter, the contents of the experiment will be described.

In this experiment, a liquid crystal panel subjected to a discharge treatment (hereinafter, referred to as a “treated panel”) and a liquid crystal panel not subjected to the treatment (hereinafter, referred to as an “untreated panel”) were manufactured. For these panels, the surface energy and the contact angle on the panel surface Pa were measured. The panel used in the experiment had a size of 15 inches. Further, in this experiment, it was confirmed that the panel surface Pa before the discharge treatment was contaminated with silicon oil.

Thereafter, a polarizing film was stuck on the panel surface Pa, and the liquid crystal panel P stuck with the polarizing film was held in a high-temperature environment of 60 ° C., and a high-temperature storage durability test was performed. It was checked whether it peeled off. The table below summarizes the surface energy of the panel surface Pa, the contact angle of the panel surface Pa, and the time (hrs) required for peeling off the polarizing film.

[0034]

[Table 1] Note: The surface energy values shown here are JIS or AS
The value is based on the wetting reagent based on the “wetting tension test method” described in TM.

This experiment confirmed that the treated panel subjected to the discharge treatment had a larger surface energy, a smaller contact angle, and improved wettability than the untreated panel not subjected to the discharge treatment. .

In this experiment, in the case of an untreated panel which was not subjected to a discharge treatment, when the liquid crystal panel P to which the polarizing film was attached was kept in a high temperature environment of 60 ° C.
Before 0 hour, peeling of the polarizing film was confirmed. On the other hand, in the case of the treated panel subjected to the discharge treatment, when the liquid crystal panel P on which the polarizing film is adhered is kept in a high-temperature environment of 60 ° C., peeling of the polarizing film is not confirmed even after 1000 hours, It was confirmed that the durability was improved by the discharge treatment.

By the way, if the panel protection tray 5 as described above is not provided, the quartz electrode 11 faces the terminal electrode portion 8 of the panel as the moving stage 3 moves, and a high voltage of 20 kV is directly applied to the terminal electrode portion 8. May be applied.
In such a case, the discharge concentrates on the terminal electrode portion 8 and a large potential difference occurs between the adjacent electrodes, and a discharge may occur between these electrodes. Further, a discharge may occur between the upper and lower substrates of the panel, and such a discharge may damage the panel P. However, in the present embodiment, the terminal electrode portion 8 is provided on the panel protection tray 5.
As a result, it is prevented that a high voltage is directly applied to the terminal electrode portion 8 and the panel P is prevented from being broken.

The present inventor has calculated the voltage applied between the information electrode and the scanning electrode in the discharging process as shown in FIG. According to this, the quartz electrode 11
The effective voltage applied between the scanning electrode and the information electrode was 1 mV or less, though the voltage applied to the scanning electrode was as high as 20 kV. That is, since a voltage high enough to invert the liquid crystal molecules is not applied, it is presumed that there is no influence on the inside of the liquid crystal panel.

By the way, the surface energy of the panel surface Pa is highest immediately after the discharge treatment, decreases as time passes, and the wettability deteriorates with time. According to the results of experiments conducted by the present inventors, as shown in FIG. 5, the surface energy of 54 dyn / cm immediately after the discharge treatment was reduced to about 40 dyn / cm after 300 hours. Therefore, it is desirable to attach the polarizing film as soon as possible after the discharge treatment.

In the above-described embodiment, the discharge processing step is performed after the liquid crystal injection step. However, the present invention is not limited to this. Of course, the discharge processing step is performed before the liquid crystal injection step. You may.

[0041]

As described above, according to the present invention,
The adhesive strength of the polarizing film is improved, and the polarizing film in a large-sized liquid crystal panel is hardly peeled off even when subjected to heat shrinkage.

In the case where the discharging process is performed, if the covering means formed of a conductor and grounded is disposed so as to cover the terminal electrode portion formed on the liquid crystal element, the electrode of the liquid crystal element may be provided. No high voltage is applied to the gap or the liquid crystal, and the liquid crystal element is not broken.

[Brief description of the drawings]

FIG. 1 is a perspective view for explaining a discharge processing step and a structure of a discharge processing apparatus.

FIG. 2 is a view taken in the direction of arrow A in FIG.

FIG. 3 is a sectional view taken along line BB of FIG. 1;

FIG. 4 is a diagram for explaining a trial calculation method of a voltage applied between a scanning electrode and an information electrode.

FIG. 5 is a diagram for explaining a temporal change in surface energy.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge processing apparatus 2 Table (liquid crystal element holding means) 3 Moving stage (liquid crystal element holding means) 5 Panel protection tray (covering means) 8 Terminal electrode part 11 Quartz electrode (electrode) 13 High frequency power supply (power supply) P Liquid crystal panel (liquid crystal) Element) Pa Panel surface (substrate surface)

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/13 G02F 1/1333 G02F 1/1335

Claims (2)

(57) [Claims] 1. A liquid crystal element holding means for holding a liquid crystal element.
An electrode disposed so as to face the liquid crystal element; a power supply connected to the electrode to apply a high voltage to the electrode; a power supply formed of a conductor and grounded;
Coating arranged to cover the terminal electrodes formed on the terminals
Means, and applying a high voltage to the electrodeDoBased on the liquid crystal element
Corona discharge treatment is applied to the surface of the liquid crystal element held by the element holding means.
ReasonAnd the coating means
High voltage was not applied to the terminal electrode part,  A discharge treatment apparatus characterized by the above-mentioned. 2. The discharge processing apparatus according to claim 1, wherein said coating means is formed of metal.