JPS63151989A - Shield panel for display element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transparent shield panel that removes static electricity that accumulates on the surface of a display element that uses high voltage to drive, such as a cathode ray tube.

[Conventional technology and problems]

Recently, in the field of display elements, in addition to the conventionally widely used cathode ray tube (CRT), various display elements have been developed and put into practical use, including liquid crystal display elements, plasma displays, electroluminescent displays, and electrochromic displays. , these display elements are OA (office automation),
AV (audio & video), FA (f
Its usage is also increasing year by year in fields such as factory automation.

Among the above-mentioned display elements, CRTs are currently most commonly used in fields where high image quality, large area display, and color display are required.

CRTs are excellent display elements capable of high image quality, large-area display, and full-color display, but because they typically require a high voltage of 10 kV or more to drive, static electricity easily builds up on the tube surface, especially in low-humidity environments. When used in , there are problems in that if you touch the tube surface with your hand, you may get a crackling discharge (electric shock), and dirt and dust are very likely to adhere to the tube surface.

In order to solve this problem, it is easy to imagine that it would be sufficient to provide a shield layer on the tube surface, and in fact, it is easy to imagine that a shield layer could be provided on the tube surface, and in fact, a metal or metal oxide layer or a multilayer structure with these can be used on a glass substrate or plastic film. Methods of preventing static electricity charging by forming a layer or kneading conductive powder into a plastic plate are being studied.

According to the above method, it is possible to prevent static electricity on the tube surface, but in general, shield panels with the above structure often have mirror-like surfaces, so the light reflectance on the surface is very high. There were problems in that the screen reflected light coming from the surroundings and the scenery behind the user was reflected on the filter, making the screen very difficult to see depending on the usage environment.

For example, in the case of a type in which a transparent conductive layer is formed on a glass substrate, means to solve the above problem include processing the glass substrate surface into a rough surface and forming a transparent conductive layer on this rough surface. There are possible ways.

Common methods for roughening the surface of a glass substrate include sandblasting and hydrofluoric acid treatment. However, for example, when the surface of a glass substrate is processed by sandblasting, the surface irregularities are larger than the thickness of the laminated conductive metal or metal oxide layer that transmits visible light, resulting in the layer being discontinuous. However, there was a problem in that the surface resistance of the layer became large. In other words, in the case of a normal shield panel, the surface resistance of the layer concerned may be approximately lx103 to lx104 (Ω/hole) in terms of sheet resistance (visible light transmittance of 85% or more), but sandblasted glass The visible light transmittance of the substrate is 85.
It is often difficult to reduce the sheet resistance value to 1x103 (Ω/hole) or less while keeping the sheet resistance value above 1.5%, and considering the increase in sheet resistance value due to outdoor use and aging, a shield panel with this structure is not very good. It can not be said.

It is thought that the above problems can be solved to some extent by using a processing sand with a small particle size for sandblasting, but on the other hand, if a small particle size side is used, it may be difficult to roughen the surface of the glass substrate. There is also the problem that it becomes difficult in itself.

In addition, in the case of hydrofluoric acid treatment, it is difficult to wash away the hydrofluoric acid, and trace amounts of residual hydrofluoric acid corrode the metal or metal oxide layer, causing adverse electrical and optical effects. There's a problem.

[Means for solving problems]

The present invention provides a glass substrate whose surface is treated with plasma of fluorine gas, fluorine-containing hydrocarbon gas alone, or a gas mixture containing the gas in order to prevent static electricity and reduce the light reflectance on the surface of the shield panel. and a shield panel for a display element in which a layer mainly made of metal or metal oxide is formed on the surface-treated surface.

In the present invention, gases that can be used for plasma processing include fluorine gas alone or CF4. Fluorine-containing hydrocarbon gas such as C, F, etc. or oxygen gas to these gases,
A mixture of nitrogen gas, argon gas, etc. may also be used.

In addition, the shield layer formed on the surface may be a thin film of metal such as gold, silver, palladium, or aluminum, or a thin film of metal oxide such as indium oxide, indium tin oxide (ITO), zinc oxide, titanium oxide, or any of these. Examples include those in which a thin multilayer film is formed.

[Effect]

If the surface of a glass substrate is treated with fluorine gas, fluorine-containing hydrocarbon gas alone, or a gas aqueous plasma containing the gas, the glass surface will be easily etched by the fluorine ions generated in the plasma, and the glass surface will be etched.
For example, compared to a glass substrate whose surface has been treated by sandblasting or the like, it is possible to form extremely fine irregularities. Therefore, a continuous metal or metal oxide layer can be formed.

By varying the plasma generation conditions, it is possible to change the light reflectance of the surface as desired, so it is possible to form a shield panel that does not have the problem of making the screen difficult to see.

In particular, according to the present invention, during etching with fluorine ions, silica (silicon dioxide) and fluorine ions react on the surface of the glass substrate, and a silicon dioxide layer doped with fluorine atoms is formed on the surface of the glass substrate. Therefore, it acts as a diffusion blocking layer for alkali metal ions such as sodium and potassium that exist inside the glass substrate, avoiding the problem of alkali metal ions diffusing into the shield layer and inhibiting electrical characteristics or causing long-term deterioration. It has the unique effect of being able to

In order to exhibit the shielding effect, the surface resistance of the shield layer is usually between lXl0''Ω/mm and lXl0'Ω/mm. Considering that the diffusion depth of alkali metal ions into the shield layer is usually within 1000 angstroms, the diffusion blocking effect of the alkali metal ions of the silicon dioxide layer doped with fluorine atoms is tremendous. be.

The plasma generation device of the present invention does not need to be particularly limited, but - as a specific example, two electrode plates are placed in a vacuum chamber so as to face each other, and after the vacuum chamber is evacuated, gas for plasma generation is applied. An example of this method is to introduce a direct current or an alternating current electric field to both electrodes. microwave,
Electromagnetic means such as ECR can also be used.

〔Example〕

Example 1 Two electrode plates were placed in a vacuum layer so as to face each other vertically with an interval of 8 an.

On the lower electrode plate, place a glass substrate (thickness 1.
[light reflectance 6.5%] was installed, and the vacuum chamber was set at 1 mTorr.
Exhausted below.

Argon/CF4 mixed gas (50150
After introducing 0.2 Torr (volume ratio), a 450 V direct current was applied to both electrodes so that the electrode plate on which the glass substrate was installed served as the negative electrode to generate plasma (current value approximately 1
．． 8 A) Glass substrate was treated for 20 minutes.

The beam thickness material ratio of the glass substrate after treatment was 2.7%.

A gold film having a thickness of 80 angstroms was formed on this surface-treated glass substrate by DC magnetron sputtering to obtain a shield panel for a display element.

This shield panel had a light reflectance of 45% and a surface resistance of 3.0×10 3 Ω/hole.

Furthermore, when this shield panel is installed closely on the surface of a CRT tube and the shield surface of the panel is brought to ground potential, static electricity on the tube surface is completely eliminated, and light rays incident from the surroundings and the user There was very little reflection of the scenery on the back side of the screen, making the screen very easy to see.

In addition, the adhesion between the glass substrate and the gold thin film layer is also severely damaged.
Even in the adhesive tape peel test, there was no part that peeled off at all.

This shield panel is rated at 30°C under the conditions of 80°C and 95RH.
There was almost no change in surface resistance even after forced aging for one day.

Example 2 Two electrode plates were arranged in a vacuum layer so as to face each other vertically with an interval of 1 Oan, and a solenoid coil was installed around the outer periphery of the vacuum chamber so that the applied electric field and magnetic field were perpendicular to each other.

A glass substrate (thickness 1.0 mm) is placed on the lower electrode plate.

(light reflectance 6.5%) was installed, and the vacuum chamber was set at 1 mTorr.
Exhausted below.

Oxygen/CF4 mixed gas (90/10
Volume ratio) is 0. After introducing lOTorr, a direct current was passed through the solenoid coil around the outer periphery of the vacuum chamber so that a magnetic field of 1000 oersted was generated in the center between both shop plates.

Further, a direct current of 500 μm was applied to both electrodes so that the electrode plate on which the glass substrate was placed served as a negative electrode to generate plasma (current value approximately 1.IA), and the glass substrate was treated for 5 minutes.

The light reflectance of the glass substrate after treatment was 2.2%.

An indium tin oxide film with a thickness of 300 angstroms was deposited on this surface-treated glass substrate by RF magnetron sputtering (the sputter target's tin oxide content was 9w).
t%) to obtain a display element shield panel.

The light reflectance of this filter is &0%, and the surface resistance is 2.
It was XlO'Ω/mouth.

Furthermore, when this shield panel is installed closely on the surface of a CRT tube and the shield surface of the panel is brought to ground potential, static electricity on the tube surface is completely eliminated, and light rays incident from the surroundings and the user There was very little reflection of the scenery on the back side of the screen, making the screen very easy to see.

This shield panel is rated at 30°C under the conditions of 80°C and 95RH.
Even after forced aging for one day, the change in surface resistance was within 50%.

[Comparative example]

Comparative example 1゜On glass substrate (thickness 1.0 mark, light reflectance 6.5%)K
A shield panel for a display element was obtained by forming an indium tin oxide film with a thickness of 300 angstroms (tin oxide content of the sputtered coupette: 9 wt %) by RF magnetron sputtering.

The light reflectance of this filter was 8.0%, and the surface resistance was 1.2×l O” 11/port.

When this shield panel was installed closely on the surface of a CRT tube and the shield surface of the panel was brought to ground potential, the static electricity on the tube surface was completely eliminated, but light rays incident from the surroundings and the user There was a lot of reflection from the back side of the screen, which could actually make the screen difficult to see depending on the usage environment.

This shield panel is rated at 30°C under the conditions of 80°C and 95RH.
When forced aging for 1 day, the surface resistance increased by 200-300%.

Comparative Example 2 The surface of a glass substrate (thickness 1.0 mark, light reflectance 6.5%) was sandblasted with alumina powder having an average particle size of 5 μm to give a light reflectance of 3.0%.

A gold film having a thickness of 80 angstroms was formed on this surface-treated glass substrate by DC magnetron sputtering to obtain a shield panel for a display element.

The light reflectance of this shield panel was 9.6%, and the surface resistance was 8.2×10 3 Ω/hole.

When this shield panel was installed closely on the surface of a CRT tube and the shield surface of the panel was brought to ground potential, the static electricity on the surface of the tube was completely eliminated, but light rays incident from the surroundings and There was a lot of reflection of the scenery on the back side of the user, which could make the screen difficult to see depending on the usage environment.

This shield panel is rated at 30°C under the conditions of 80°C and 95RH.
When forced aging for 1 day, the surface resistance is 800-1000%
increased.

Furthermore, when a peel test was performed on the shield panel before aging using adhesive tape, about 15% of the gold thin film layer was peeled off.

〔Effect of the invention〕

According to the present invention, a shield panel for display elements with extremely low surface reflectance can be obtained, so there is no problem that the screen becomes difficult to see due to the use of the shield panel, and it also has excellent aging resistance. Therefore, it has great utility in the field of display device applications.

Claims (1)

[Claims] (1) A glass substrate whose surface has been treated with plasma of fluorine gas, fluorine-containing hydrocarbon gas alone, or a mixture of gases containing the gas, and a metal or metal oxide that is conductive and transparent to visible light on the plasma-treated surface. A shield panel for display elements with a shield layer made of