JPH0992133A - Manufacture of plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a magnesium oxide film having <111> orientation being a protective film for obtaining an excellent discharge characteristic by protecting a dielectric layer, at a low temperature with high throughput, in a manufacturing method of an AC type plasma display panel(PDP). SOLUTION: In the case of forming a protective layer of a magnesium oxide to protect a dielectric layer from ion bombardment by plasma discharge by contacting with a discharge space of PDP, high frequency voltage is impressed on a base board holder 13 in a chamber 15 from a power source device 12, and plasma discharge is generated on a surface of a base board. In this condition, the magnesium oxide is evaporated from a crucible 18 by using a thermoelectron flow 16, and a magnesium oxide film is formed on a surface of the base board by an evaporation method. Since plasma discharge is generated, even at a low base board temperature of about 180 deg.C, the magnesium oxide film can be formed with high throughput by the evaporation method. The magnesium oxide film having <111> orientation has an action to reduce driving voltage of an AC type PDP since a secondary electron emitting factor is high. Particularly, it is suitable for manufacturing a plasma display panel having the large area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a plasma display panel (also referred to as a gas discharge display panel or PDP) used for a display device or the like, and more particularly to protection for protecting a dielectric layer in the gas discharge display panel. A method for forming a layer.

[0002]

2. Description of the Related Art In an AC drive type (AC) gas discharge display panel, a heat resistant protective layer is provided in order to protect the dielectric layer from ion bombardment due to discharge. The protective layer is
A magnesium oxide (MgO) film is preferably used. The magnesium oxide film is generally formed by a method of evaporating a film material by heating using electron beam irradiation and depositing it on the surface of the dielectric layer in the form of crystal growth, that is, an evaporation method.

The driving voltage of the gas discharge display panel is determined by many factors such as the element structure and the enclosed gas. The secondary electron emission coefficient of the protective layer in contact with the discharge space is one of them, and the larger the secondary electron emission coefficient is, the lower the voltage can be driven. The protective layer made of magnesium oxide has a large secondary electron emission coefficient, and is particularly suitable for the protective layer from this viewpoint.

Incidentally, the driving voltage of the gas discharge display panel is required to be further reduced from the viewpoint of the withstand voltage characteristics of the driving circuit and the power consumption when the area is increased. From the viewpoint of lowering the voltage, attention has been paid to the difference in secondary electron emission coefficient depending on the crystal orientation of the magnesium oxide film. That is, in the magnesium oxide film, it is known that the <111> orientation film has a higher secondary electron emission coefficient than the other orientation magnesium oxide films. Japanese Patent Laid-Open No. 5-23
In Japanese Patent No. 4519, the superiority of the <111> orientation film of magnesium oxide is also described in terms of change over time as a protective film.

[0005]

Conventionally, in order to obtain a <111> oriented film of magnesium oxide by a vapor deposition method using an electron beam, the film is deposited at a high substrate temperature of 230 ° C. or higher, or low. Only the method of forming at a low deposition rate of 1.5 to 3 Å / sec or less at the substrate temperature was known. However, when the magnesium oxide film is formed at a high substrate temperature of 230 ° C. or higher, the lead (Pb) component in the low-melting-point glass that is the underlayer diffuses into the magnesium oxide film, and such a magnesium oxide film is formed in the AC-PDP. When used as a protective layer for the above, there is a problem that a favorable low driving voltage cannot be obtained. On the other hand, a low deposition rate of 1.5 to 3Å / sec or less is difficult to adopt from the viewpoint of throughput.

In view of the above, the present invention makes it possible to suppress the diffusion of the lead component from the underlayer when forming the <111> orientation film of magnesium oxide in the production of the AC discharge type plasma display panel. An object of the present invention is to provide a method for manufacturing a plasma display panel, which can adopt a low substrate temperature and can form the alignment film with high throughput.

[0007]

In order to achieve the above object, in the method for manufacturing an AC discharge type plasma display panel (AC-PDP) according to the present invention, the step of forming a magnesium oxide layer as a protective layer is performed. The method is characterized by including a procedure of generating a plasma discharge on the film surface and a procedure of forming magnesium oxide by a vapor deposition method in a state where the plasma discharge is generated.

Further, in the preferable method for manufacturing an AC-PDP of the present invention, in the step of generating the plasma discharge, a discharge gas of argon gas, oxygen gas, or a mixed gas of argon and oxygen is used in the chamber. A high frequency voltage is applied to the substrate holder which is introduced and attached with an insulating substrate for forming a film to generate plasma discharge.

In the method of manufacturing an AC-PDP according to the present invention, plasma discharge is generated on the substrate surface,
Even at a low substrate temperature of less than 230 ° C., a protective layer made of a magnesium oxide film oriented in a crystal orientation <111> can be obtained at a high film forming rate of 5 Å / sec or more.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a cross-sectional view of essential parts schematically showing the structure of a general AC-PDP manufactured by the method of the present invention. The AC-PDP has a first insulating substrate 1a and a second insulating substrate 1b made of glass, which are arranged on the front surface and the back surface. A large number of transparent display electrode pairs 2a and 2b arranged in parallel with each other are formed on the first insulating substrate 1a,
The insulator layer 6a is formed so as to cover these. Further, a protective layer 7 made of magnesium oxide is formed so as to cover the insulating layer 6a. The protective layer 7 is provided to protect the dielectric layer 6a from ion bombardment due to discharge.

Between the first and second insulating substrates,
A discharge gas space 5 is provided, and in the discharge gas space 5,
A Penning gas composed of, for example, helium and xenon is enclosed as a discharge gas. The discharge spaces 5 are partitioned from each other by the partition walls 4 to form unit light emitting regions. On the second insulating substrate 1b, a data electrode 3 for selectively emitting light in the unit light emitting region and a dielectric layer 6b that covers these are formed, and a phosphor 8 of a predetermined emission color is further formed thereon. Is applied. Each of the dielectric layers 6a and 6b is formed by printing a low melting point glass paste in a predetermined shape and firing it.

In the AC-PDP of the above-mentioned type, when a predetermined drive voltage forming an alternating pulse such that the relative potential between them is alternately inverted is applied to the pair of display electrodes 2a and 2b, each application is performed. Discharge occurs on the surface of the dielectric layer 6a, and the ultraviolet rays generated thereby excite the phosphor 8 to emit light.

The AC-PDP having the above structure has a step of separately providing predetermined constituent elements on each of the glass substrates 1a and 1b, a step of disposing the glass substrates 1a and 1b to face each other and sealing the periphery, and a discharge. It is manufactured through a process of filling gas. In the process, the protective layer 7 formed on the first glass substrate 1a side is formed by the vapor deposition method using plasma discharge according to the present invention.

FIG. 1 illustrates a schematic structure of a film forming apparatus for forming a magnesium oxide film by carrying out the method of the present invention. The film forming apparatus includes a chamber 15, a thermionic flow heating type evaporation source 9, a heater 10 and an electron beam source 11 for irradiating an electron beam, and a high frequency power source device (RF power source) for generating a plasma discharge. Device) 12. In this film forming apparatus, the substrate holder 13 for setting the substrate is
The RF power supply device 12 is electrically insulated from the chamber 15.
It is connected to the.

The evaporation source 9 is a heat-resistant container (crucible) 1 for containing a filament 17 for emitting a thermoelectron stream 16 and magnesium oxide as an evaporation substance (target) of a film material.
8. A magnetic flux generator (not shown) that deflects the thermionic flow to the target, and a support 19, controls the irradiation energy of the thermionic flow 16 to heat the magnesium oxide,
Allow to evaporate.

Film formation of the protective layer using the film forming apparatus of FIG.
For example, it is performed as follows. The substrate holder 13 has
A glass substrate 1a on which a predetermined structure is formed is installed, and an RF power supply device 12 is connected to the glass substrate 1a. Then chamber 15
The inside of the chamber is evacuated by a vacuum pump (not shown), and the inside of the chamber 15 is evacuated to about 1 × 10 ⁻⁵ Torr, for example. In parallel with this exhaust, the heater 10 heats the glass substrate 1a.

After the temperature of the substrate surface reaches about 180 ° C., the chamber 1 is passed through a pipe 20 from a gas cylinder (not shown).
Argon (Ar) gas is introduced into 5. At this time, the flow rate is controlled by the mass flow controller 14, and the argon partial pressure in the chamber 15 is set to a predetermined value, for example, 2 × 1.
Keep at 0 ^-3 Torr.

After the partial pressure of argon in the chamber 15 is stabilized at the above-mentioned predetermined value, the RF power supply 12 moves the substrate holder 1
A high frequency voltage is applied to 3 to generate plasma discharge on the surface of the glass substrate 1a. When it is difficult to maintain the plasma discharge due to the low density of the power supplied to the plasma discharge due to the application of the high frequency voltage, the plasma discharge trigger from the electron beam source 11 to the surface of the glass substrate 1a is used as a continuous trigger of the plasma discharge. And a plasma discharge is maintained.

Next, the filament 17 of the evaporation source 9 is heated to generate a thermoelectron stream 16 to evaporate magnesium oxide. As a result, a protective layer made of magnesium oxide is formed on the glass substrate 1a. At this time, the thermoelectron flow of the evaporation source 9 is controlled so that the deposition rate is, for example, 10Å / sec.

When the formation of the protective layer having a film thickness of, for example, about 5000 Å is completed after a predetermined time has passed, the evaporation source 9 and the heater 10 are turned off, and the application of the high frequency voltage is stopped. After waiting for the temperature of the glass substrate 1a to drop, the chamber 15
The inside is returned to atmospheric pressure, and the glass substrate 1a is taken out and sent to the next step.

FIG. 3 is a graph showing the relationship between the RF power per substrate area, that is, the density of power supplied to the plasma discharge by the high frequency voltage, and the crystal orientation of the formed magnesium oxide film. In the figure, the vertical axis represents each crystal orientation <111> of the magnesium oxide film obtained by X-ray diffraction.
And the peak intensity at <200>. As can be easily understood from the figure, the peak intensity of the <111> crystal orientation increases and the peak intensity of the <200> crystal orientation decreases within a certain range by supplying high frequency power for plasma discharge. Therefore, the crystal orientation <111
A magnesium oxide film oriented in> is obtained. here,
If a high-frequency power having a too high density is applied, the crystallinity of the entire film is deteriorated, and the obtained magnesium oxide film may become an amorphous film. Therefore, in order to obtain a favorable <111> -oriented magnesium oxide film, it is preferable to set the high-frequency power supply density in the range of 50 to 300 mW / cm ² .

Although the present invention has been described based on its preferred embodiments, the method for manufacturing a plasma display panel of the present invention is not limited to the above-mentioned embodiments, and the above-mentioned embodiments are not limited thereto. A method of manufacturing a plasma display panel, which is variously modified and changed from the above, is also included in the scope of the present invention.

For example, in the above embodiment, an example of manufacturing an AC-PDP using Ar gas as a plasma discharge gas generated on the surface of a substrate during deposition of a magnesium oxide film has been described. However, oxygen (O ₂ ) is used as the discharge gas. You may use as.
Further, although the surface discharge type AC-PDP is illustrated, the present invention is also applicable to the facing discharge type AC-PDP. Furthermore,
In the above-described embodiment, the type of evaporation source, the structure of the chamber, the conditions for controlling evaporation, etc.
> It can be appropriately changed within a range where an alignment film can be obtained.

[0024]

According to the method of manufacturing a plasma display panel of the present invention, a <111> orientation film of magnesium oxide for protecting a dielectric layer and obtaining good discharge characteristics is formed at a relatively low temperature. Since the film can be formed at high speed, a good protective film for the film chamber can be formed with high throughput. The method of the present invention can be particularly preferably used for manufacturing a large-area plasma display panel or the like.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a schematic configuration of a magnesium oxide film forming apparatus for carrying out the method of the present invention.

FIG. 2 is a general AC-PDP manufactured by the method of the present invention.
Sectional drawing which shows the structure of FIG.

FIG. 3 is a graph showing the relationship between the power supply density by applying a high frequency voltage to the substrate and the crystal orientation of the magnesium oxide film.

[Explanation of symbols]

 1a, 1b Glass substrate 2a, 2b Display electrode 3 Data electrode 4 Partition 5 Discharge space 6a, 6b Dielectric layer 7 Protective layer 8 Fluorescent substance 9 Evaporation source 10 Heater 11 Electron beam source 12 High frequency power supply 13 Substrate holder 14 Mass flow controller 15 Chamber 16 Thermionic Flow 17 Filament 18 Crucible 19 Support 20 Pipe

Claims (5)

[Claims] 1. A pair of insulative substrates, electrode parts arranged on both of the insulative substrates and facing each other, a dielectric layer covering the electrode parts, and at least one dielectric layer. In a method of manufacturing an AC-driven plasma display panel having a covering vapor deposition-formed magnesium oxide layer and performing display by discharge in a discharge gas space, the step of forming the magnesium oxide layer involves plasma discharge on the deposition surface. A method for manufacturing a plasma display panel, which comprises a step of generating and a step of performing vapor deposition in a state where a plasma discharge is generated, and mainly forming a <111> orientation film of magnesium oxide. 2. The method for manufacturing a plasma display according to claim 1, wherein the vapor deposition is performed by an electron beam vapor deposition method in which an electron beam is irradiated to heat and vaporize a vapor deposition material. 3. The plasma discharge is generated by introducing a discharge gas into a deposition chamber and applying a high frequency voltage to a substrate holder that supports an insulating substrate on which a film is formed. A method for manufacturing the plasma display panel described. 4. The method for manufacturing a plasma display panel according to claim 3, wherein the discharge gas is any one of an argon gas, an oxygen gas, and a mixed gas of argon and oxygen. 5. The plasma display panel according to claim 3, wherein the power density supplied to the plasma discharge by applying the high frequency voltage is in the range of 50 to 300 mW / cm ² . Production method.