JP2002075226A - Plasma display panel and its manufacturing method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma display panel that realizes an excellent display quality with good discharge characteristics, and a manufacturing method for manufacturing the panel stably. SOLUTION: In the plasma display panel, a magnesium oxide membrane having an optical index of refraction of 1.60 or less to the light of wavelength of 550 nm is formed on the uppermost surface of at least one of the substrates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel (PDP) using gas discharge light emission for use in a color television receiver or display for displaying characters or images, and a method and apparatus for manufacturing the same. is there.

[0002]

2. Description of the Related Art A conventional plasma display panel will be described below with reference to the drawings. FIG. 4 is a cross-sectional view schematically showing an AC type (AC type) plasma display panel.

In FIG. 4, reference numeral 41 denotes a front glass substrate, on which a display electrode 42 is formed. Further, the display electrode 42 is provided on the dielectric glass layer 4.
3 and a magnesium oxide (MgO) protective layer 44.

Reference numeral 45 denotes a rear glass substrate. On the rear glass substrate 45, address electrodes 46, partition walls 47, and phosphor layers (50 to 52) are provided.
Reference numeral 9 denotes a discharge space for filling a discharge gas. The phosphor layer has red 50, green 51, and blue 52 for color display.
Are arranged in order. Each of the phosphor layers (50 to 52) emits and emits light by vacuum ultraviolet rays (wavelength: 147 nm) having a short wavelength generated by discharge.

The following materials are generally used as the phosphors constituting the phosphor layers 50 to 52.

“Blue phosphor”: BaMgAl ₁₀ O ₁₇ : Eu “Green phosphor”: Zn ₂ SiO ₄ : Mn or BaAl ₁₂
O _19: Mn "red phosphor": Y ₂ O _3: Eu or (YxGd1-
x) BO ₃ : Eu A gas mixture of Ne—Xe is sealed in the discharge space between the two glass substrates, and the phosphor layers (50 to 52) are irradiated with vacuum ultraviolet light (147 nm) having a short wavelength generated by the discharge. Are excited, and visible light of R, G, B is emitted from the front glass substrate side to perform color display.

[0007]

However, the discharge characteristics of the plasma display panel, such as the discharge voltage, greatly depend on the conditions for forming the protective layer 44 and the film quality. In order to lower the discharge voltage, a protective layer having good electron emission characteristics is required. Generally, an MgO film having a large secondary electron emission coefficient is used as a protective layer, but a sufficient low voltage has not been achieved.

In view of the above problems, the present invention has an object to provide a plasma display panel capable of discharging at a relatively low voltage by realizing a protective layer having good electron emission characteristics. is there.

[0009]

In order to achieve the above object, a plasma display panel according to the present invention comprises a plasma display panel having a protective layer formed on the outermost surface of at least one substrate, wherein the porosity of the protective layer is reduced. 10
% Or more.

In a plasma display panel having a magnesium oxide film formed on the outermost surface of at least one substrate, the magnesium oxide film has an optical refractive index of 1.65 or less with respect to light having a wavelength of 550 nm. Features.

In a plasma display panel having a magnesium oxide film formed on the outermost surface of at least one of the substrates, the magnesium oxide film has a film density of 3.
It is not more than 3 g / cm ³ .

In the above structure, the protective layer or the magnesium oxide film preferably has a columnar structure or a network structure.

Preferably, the protective layer or the magnesium oxide film is heat-treated.

Further, a method of manufacturing a plasma display panel according to the present invention is a method of manufacturing a plasma display panel in which a protective layer is formed on the outermost surface of at least one substrate by a vacuum deposition method, wherein a deposition direction is switched during the deposition. It is characterized by the following.

A method of manufacturing a plasma display panel, wherein a protective layer is formed on the outermost surface of at least one substrate by a sputtering method, wherein a sputtering direction is switched during sputtering.

Further, a plasma display panel manufacturing apparatus according to the present invention is a plasma display panel manufacturing apparatus for forming a protective layer on the outermost surface of at least one substrate by a vacuum deposition method, wherein a deposition direction is switched during the deposition. It is characterized by having a mechanism.

[0017] Also, a plasma display panel manufacturing apparatus for forming a protective layer on the outermost surface of at least one substrate by a sputtering method, characterized by having a mechanism for switching a sputtering direction during sputtering.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A plasma display panel according to the present invention will be described based on specific embodiments.

Embodiment 1 FIG. 2 is a sectional view schematically showing an AC surface discharge type plasma display panel according to an embodiment of the present invention. Although only one cell is shown in FIG. 2, a PDP is formed by arranging a large number of cells that emit red, green, and blue light.

This PDP has a display electrode 22, a dielectric glass layer 23, and a protective layer (MgO film) on a front glass substrate 21.
A front plate on which a base plate 24 is disposed and a rear plate on which an address electrode 26, a visible light reflecting layer 27, a partition wall 28, and a phosphor layer 29 are disposed on a rear glass substrate 25 are laminated to form between the front plate and the rear plate. A discharge gas is sealed in a discharge space to be discharged.

As the composition of the phosphor material constituting the phosphor layer, those generally used for the phosphor layer of PDP can be used. Specific examples thereof include “blue phosphor”: BaMgAl ₁₀ O ₁₇ : Eu “green phosphor”: Zn ₂ SiO ₄ : Mn “red phosphor”: (Y, Gd) BO ₃ : Eu. .

The protective layer (MgO film) 24 has a columnar or mesh-like structure, and has some voids in the film. Assuming that the volume ratio of the voids in the MgO film is defined as the porosity, in the present embodiment, a film having a porosity of 10% or more was used. In addition, the film density of the MgO film decreases in accordance with the porosity, and the film density is 3.3 g / cm ³ or less.

This MgO film is formed by, for example, a vacuum evaporation method or a sputtering method.
It can be formed by switching the deposition direction during deposition or sputtering.

The front glass substrate on which the MgO film was formed was heat-sealed and sealed with the rear glass substrate.

At the time of driving the PDP, as shown in FIG.
After connecting each driver and panel drive circuit 90 to the PDP and applying an address discharge between the scan electrode 91a and the address electrode 92 of the cell to be lit, a pulse voltage is applied between the display electrodes 91a and 91b. The voltage is applied to perform sustain discharge. Then, the cell emits ultraviolet light in accordance with the discharge, and is converted into visible light by the phosphor layer. An image is displayed by lighting the cell in this manner.

(Embodiment 2) In the present embodiment, the protective layer (MgO film) 24 of the first embodiment is a MgO film having a columnar or network structure, and has an optical refractive index of 55 nm.
A film that is 1.65 or less for 0 nm light was used. This MgO film is formed by, for example, a vacuum evaporation method or a sputtering method. In particular, in order to form a network structure, the MgO film can be formed by switching the evaporation direction during evaporation or during sputtering.

The front glass substrate on which the MgO film had been formed was heat-sealed and sealed with the rear glass substrate.

[0028]

EXAMPLE A method for forming an MgO film used in this embodiment and the results of evaluating the discharge characteristics of a PDP using the same will be described.

FIG. 1 shows an apparatus for forming an MgO film according to this embodiment. In the film forming apparatus, three MgO evaporation sources 1 are provided. The front glass substrate 2 is set in a vacuum chamber 5 after forming the display electrodes 3 and the dielectric layer 4. An MgO film 6 was formed by introducing oxygen gas into the vacuum chamber 5 and heating the deposition source 1 with an electron beam. In this embodiment, the film is formed at a substrate temperature of 250 ° C. for 5 minutes,
The film thickness of Å was obtained.

The columnar MgO film was formed by keeping the deposition direction constant.

Further, the MgO film having a network structure can be formed by sequentially switching the heating of each deposition source 1 by the electron beam during the deposition, for example, every one minute, and changing the deposition direction with time.

The front glass substrate on which the MgO film was formed was heated to 500 ° C. in a heating furnace and then sealed with the rear glass substrate.

Table 1 shows the measurement results of the MgO film structure, the porosity, the density, the refractive index for light having a wavelength of 550 nm, the discharge voltage between the display electrodes of the PDP, and the luminous efficiency in the PDP of this embodiment.

[0034]

[Table 1]

Panel No. Nos. 1 to 4 are Mg of the present embodiment.
This is a panel using an O film. Panel No. 5,6
Is a comparative example using a conventional MgO film.

By using the MgO film of this embodiment, the discharge voltage between the display electrodes was reduced, and as a result, the discharge current was reduced and the luminous efficiency was improved.

This is because an MgO film having a large porosity and a small film density has a larger surface area and a larger area capable of emitting electrons in comparison with a conventional MgO film. Is considered to have increased and the discharge voltage decreased.

It is also conceivable that the electron emission probability of the MgO film having a small refractive index similarly increased and the discharge voltage decreased.

By realizing the MgO film having a large surface area as described above, the discharge voltage could be reduced. On the other hand, however, such a film has a large surface area, so that the impurity gas is easily adsorbed during the manufacturing process. And the like, but was effective for the discharge stability, but the voltage lowering effect was obtained without performing the heat treatment.

The porosity is 15% or more, and the film density is 3.1 g.
A film having a refractive index of 1.6 / cm ³ or less and a refractive index of 1.6 or less can be relatively easily obtained by forming a network structure. As the number of times of switching the deposition direction increases, the porosity increases, the film density decreases, and the refractive index decreases. The rate dropped.

In this embodiment, the film is formed by the vacuum evaporation method, but the film can be formed by the sputtering method.

Further, MgO was used as the protective layer.
A mixed layer of MgF or (MgO + MgF) may be used, and a film of an oxide of an alkaline earth metal, a fluoride of an alkaline earth metal, or a mixture thereof may be used, and is not limited to this embodiment. .

In the above embodiment, the surface discharge type PDP is exemplified. However, the present invention can be applied to all PDPs requiring a protective layer, such as a facing discharge type PDP.

[0044]

As described above, according to the present invention, it is possible to obtain a protective layer having good electron emission characteristics, to reduce the discharge characteristics when a panel is formed, and as a result, to obtain a high luminous efficiency. A plasma display panel can be realized.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an apparatus for forming a MgO film according to an embodiment of the present invention.

FIG. 2 is a schematic sectional view of an AC surface discharge type plasma display panel according to the present embodiment.

FIG. 3 illustrates a PDP in which a driving circuit is connected to the PDP of the present embodiment.
Diagram showing DP display device

FIG. 4 is a schematic sectional view of a conventional AC surface discharge type plasma display panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 MgO evaporation source 2 Front glass substrate 3 Display electrode 4 Dielectric layer 5 Vacuum chamber 6 MgO film

Claims (25)

[Claims] 1. A plasma display panel having a protective layer formed on the outermost surface of at least one substrate, wherein the porosity of the protective layer is 10% or more. 2. The plasma display panel according to claim 1, wherein the porosity of the protective layer is 15% or more. 3. The plasma display panel according to claim 1, wherein the protective layer is a film of an oxide of an alkaline earth metal, a fluoride of an alkaline earth metal, or a mixture thereof. 4. The plasma display panel according to claim 1, wherein the protective layer is a magnesium oxide film. 5. A plasma display panel having a magnesium oxide film formed on the outermost surface of at least one substrate, wherein the magnesium oxide film has an optical refractive index of 550 nm.
a plasma display panel for light of m. 6. The plasma display panel according to claim 5, wherein an optical refractive index of the magnesium oxide film is 1.60 or less for light having a wavelength of 550 nm. 7. A plasma display panel in which a magnesium oxide film is formed on the outermost surface of at least one substrate, wherein the magnesium oxide film has a film density of 3.3 g / cm ³ or less. . 8. The magnesium oxide film having a film density of 3.
The plasma display panel of claim 7, characterized in that 1 g / cm ³ or less. 9. The plasma display panel according to claim 1, wherein the protective layer or the magnesium oxide film has a columnar structure. 10. The plasma display panel according to claim 1, wherein the protective layer or the magnesium oxide film has a network structure. 11. The plasma display panel according to claim 1, wherein the protective layer or the magnesium oxide film is formed by a vacuum deposition method. 12. The plasma display panel according to claim 1, wherein the protective layer or the magnesium oxide film is formed by a sputtering method. 13. The plasma display panel according to claim 1, wherein the protective layer or the magnesium oxide film according to claim 1 is heat-treated. 14. A method of manufacturing a plasma display panel, wherein a protective layer is formed on the outermost surface of at least one of the substrates by a vacuum deposition method, wherein a deposition direction is switched during the deposition. . 15. The method according to claim 12, wherein the deposition direction is switched at least three times. 16. A method for manufacturing a plasma display panel, wherein a protective layer is formed on the outermost surface of at least one substrate by a sputtering method, wherein a sputtering direction is switched during sputtering. 17. The method for manufacturing a plasma display panel according to claim 16, wherein the sputtering direction is switched at least three times or more. 18. The method of manufacturing a plasma display panel according to claim 14, wherein after forming the protective layer, the protective layer is heat-treated. 19. The plasma display according to claim 14, wherein the protective layer is a film of an oxide of an alkaline earth metal, a fluoride of an alkaline earth metal, or a mixture thereof. Panel manufacturing method. 20. The method according to claim 14, wherein the protective layer is a magnesium oxide film. 21. A plasma display panel manufacturing apparatus for forming a protective layer on the outermost surface of at least one substrate by a vacuum deposition method, comprising: a mechanism for switching a deposition direction during deposition. Manufacturing equipment. 22. The plasma display panel manufacturing apparatus according to claim 21, comprising a plurality of evaporation sources. 23. A plasma display panel manufacturing apparatus for forming a protective layer on the outermost surface of at least one substrate by a sputtering method, comprising: a mechanism for switching a sputtering direction during sputtering. manufacturing device. 24. The apparatus for manufacturing a plasma display panel according to claim 23, comprising a plurality of sputtering sources. 25. A plasma display panel display device comprising a plasma display panel and a driving circuit for driving the plasma display panel, wherein the plasma display panel is any one of claims 1 to 13. A plasma display panel display device, characterized in that: