JPH11345572A - Plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display a good image until the end of the operation life of a plasma display panel by preventing picture quality from being impaired by dust or fine particles clinging to the display surface of the plasma display panel. SOLUTION: A plasma display panel 100 has an almost transparent photocatalyst thin film 32 formed in a thickness of, e.g. 50 to 200 nm, over the entire surface of a front substrate 21 opposite to the side on which transparent electrodes 23 are placed, i.e., over a display surface. Phosphor layers 28 are applied to portions separated by barrier ribs 27. In addition to a normal visible light emitting phosphor which radiates visible light in response to vacuum ultraviolet rays, a near ultraviolet emitting phosphor which radiates near ultraviolet rays in response to the vacuum ultraviolet rays is contained in each phosphor layer 28.

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, and more particularly, to a plasma display panel which prevents image quality from being deteriorated by dust and fine particles attached to a display surface.

[0002]

2. Description of the Related Art In a plasma display panel, a minute space is provided between two glass plates, electrodes are arranged in a matrix, and a discharge gas is sealed. Then, a phosphor layer is provided in accordance with the arrangement of the electrodes, a gas discharge is generated at the intersection of the electrodes to which a voltage is applied, and the ultraviolet light generated thereby excites the phosphor to emit light. And display information. And red at each electrode intersection,
Color images can be displayed by regularly arranging phosphors having blue and green light emission characteristics.

However, when commercializing a plasma display panel, it is necessary to arrange a filter in front of the panel in order to prevent reflection of external light, block infrared rays emitted from the panel surface, and protect the panel surface. And
This filter is generally non-removable for safety reasons.

[0004]

FIG. 5 shows a cross-sectional structure of a plasma display panel device 90 in which a plasma display panel and a device for operating the plasma display panel are incorporated in a housing.

As shown in FIG. 5, a plasma display panel device 90 is roughly divided into a plasma display panel 11, devices such as a driving circuit and a signal circuit for operating the plasma display panel 11, and a housing for accommodating them. 15. In FIG. 5, a space for accommodating a drive circuit, a signal circuit, and the like is shown as a device accommodation space 14.

The housing 15 has a box shape, and is arranged so that the display surface of the plasma display panel 11 faces the opening OP, and the filter OP is provided in the opening OP. The problem here is the gap 13 provided between the plasma display panel 11 and the filter 12.

The housing 15 is provided with a heat-dissipating slit 16 for heat dissipation, and dust and fine particles that cause dirt enter the heat-dissipating slit 16. Dust and fine particles adhere to the display surface of the plasma display panel 11 through the gap 13, which is easily charged with static electricity. If this occurs over a long period of time, the display image on the plasma display panel 11 becomes difficult to see and the image quality deteriorates. However, as described above, the filter 12 is not removable, so that the The display surface of the display panel 11 could not be cleaned.

As an example of a plasma display panel device which facilitates removal of a filter, the configurations disclosed in JP-A-9-81046 and JP-A-9-107531 can be cited. This is a configuration for the convenience of time, and is not a configuration for cleaning the display surface of the plasma display panel 11,
Not easily removable by the user.

If the gap 13 between the plasma display panel 11 and the filter 12 is eliminated, such a problem does not occur. However, if the plasma display panel 11 and the filter 12 are brought into close contact with each other in order to eliminate the gap 13, a Newton ring is formed. As a result, there is a problem that the displayed image becomes difficult to see.

[0010] The Newton ring is a phenomenon in which when light is applied to a portion where a convex surface and a flat surface are in contact with each other, an annular bright and dark fringe of light is formed around the contact portion. The occurrence of a Newton ring, which is a problem, will be described with reference to FIG. A resin plate such as acrylic is often used for the filter 12, and the filter 12 is deformed by heat transfer from the heated plasma display panel 11, particularly when this deformation becomes convex on the plasma display panel 11 side. Then, a Newton ring is generated due to the contact between the filter and the plasma display panel 11.

FIG. 6 shows an example in which the filter 12 has a convex portion. The filter 12 has a curved shape and a plasma display panel 11 (made of two glass plates).
A Newton ring is generated around the contact portion CP due to light interference between the contact portion CP.

When a glass plate is used for the filter 12, Newton's rings are unlikely to occur, but the plasma display panel 11 and the filter 12 come into contact with each other due to vibration when the apparatus is transported or used in a vehicle. In order to prevent such a problem, it is necessary to provide a gap between the two.

As described above, the gap 13 is indispensable between the filter 12 and the plasma display panel 11, but there is a problem that the provision of the gap 13 causes dust and fine particles to adhere to the surface of the plasma display panel 11. Was.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is intended to prevent a decrease in image quality due to dust or fine particles attached to a display surface of a plasma display panel.
An object of the present invention is to provide a plasma display panel capable of displaying an excellent image until the operating life of the plasma display panel is reached.

[0015]

According to the present invention, there is provided a plasma display panel according to the present invention, wherein a first substrate is disposed so as to face in parallel with the first substrate, and the first substrate is provided. A second substrate forming a discharge space filled with a discharge gas between the second substrate and a phosphor layer provided corresponding to the discharge space and generating mainly visible light by ultraviolet rays generated by the gas discharge; Of the first and second substrates,
It is arranged at least on the outer surface that will be the image display surface,
A photocatalytic thin film having a photocatalytic action by ultraviolet light.

According to a second aspect of the present invention, in the plasma display panel, the photocatalytic thin film is a substance that acts on moisture in the air by irradiating ultraviolet rays to generate hydroxyl radicals on the surface.

According to a third aspect of the present invention, in the plasma display panel, the photocatalytic thin film is a titanium oxide, a zinc oxide, or a double oxide containing at least one of titanium and zinc.

According to a fourth aspect of the present invention, in the plasma display panel according to the fourth aspect, the phosphor layer emits visible light by receiving ultraviolet light generated by the gas discharge, and the phosphor layer is formed by the gas discharge. It is a mixture with a near-ultraviolet light-emitting phosphor that emits near-ultraviolet rays upon receiving ultraviolet rays.

According to a fifth aspect of the present invention, in the plasma display panel according to the fifth aspect, the phosphor layer may be made of BaSi ₂ O ₅ : Pb ²⁺ , SrB ₄ O ₇ F: E as the near-ultraviolet light-emitting phosphor.
u ²⁺ , (Ba, Sr, Mg) ₃ Si ₂ O ₇ : Pb ²⁺ , (B
_{a, Mg, Zn) 3 Si} 2 O 7: Of Pb ^2+, contains at least one.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS <1. Apparatus Configuration> The plasma display panel is classified into an AC type and a DC type according to the driving method. In the following description, an AC three-electrode surface discharge type plasma display panel will be described as an example. The present invention can be applied to a plasma display panel other than this type.

FIG. 1 is a perspective view (partially a sectional view) of a sectional configuration of an AC three-electrode surface discharge type plasma display panel. However, in FIG. 1, for convenience of explanation, the substrate 21
And 22 are shown open vertically.

In FIG. 1, a strip-shaped transparent electrode 23 is formed on a front substrate 21 as a scanning and sustaining electrode for performing surface discharge. The transparent electrode 23 is usually made of ITO (Indium Tin Oxid
e) Or formed of SnO ₂ . However, the transparent electrode 23
Since the sheet electrode has a high sheet resistance, the bus electrode 24 is formed along the transparent electrode 23 with a thick silver film having a lower sheet resistance than the transparent electrode 23. Further, a (transparent) dielectric layer 25 made of a low-melting glass or the like is formed thereon. The dielectric layer 25 is covered with a protective layer 26 made of MgO. The protective layer 26 is a portion that not only functions to protect the dielectric layer 25 but also performs a secondary electron emission function and a wall charge accumulation function during gas discharge. On the surface of the front substrate 21 opposite to the side on which the transparent electrodes 23 are provided, that is, on the display surface, a substantially transparent photocatalytic thin film 32 has a thickness of, for example, 50 nm or less.
It has a thickness of 200 nm and is entirely disposed.

The back substrate 22 has a band-shaped data electrode 30
Is formed of a thick silver film or the like, and the data electrode 30 is
Underlayer 31 made of a dielectric material formed on the surface of surface 2
It is completely covered with. Then, the partition walls 27 that partition the display pixels are formed of low melting point glass or the like along the data electrodes 30. Further, a phosphor layer 28 is applied and formed on a portion separated by the partition wall 27.

The front substrate 21 and the rear substrate 22 formed in this manner are superimposed on each other so that the pair of transparent electrodes 23 and the data electrodes 30 face each other and are orthogonal to each other. , Ne- in each discharge space.
A mixed gas (discharge gas) such as Xe is, for example, 500 Torr.
After sealing at about r, the plasma display panel 100 is completed by sealing (sealing). The transparent electrode 23
And the data electrode 30 form one display cell.

<1-1. Configuration of Photocatalytic Thin Film> The photocatalytic thin film 32 is made of, for example, titanium oxide (TiO 2) having an anatase crystal structure.
₂ ) receives ultraviolet rays generated inside the plasma display panel 100 and transmitted through the front substrate 21, and decomposes dust and fine particles composed of organic substances attached to the surface of the photocatalytic thin film 32 (antifouling action). have.

Here, the antifouling action of the photocatalytic thin film 32 will be described. For example, when the titanium oxide is irradiated with ultraviolet rays, "holes" in a state where electrons are deficient are generated on the surface of the titanium oxide, and water in the air near the surface is decomposed into H ⁺ and .OH. OH is called a hydroxy radical and has a strong oxidizing power. The organic matter on the surface of the photocatalytic thin film 32 is oxidized by this, and the molecular bond is cut, for example, CO ₂
Is decomposed into such a gas and disappears from the surface of the photocatalytic thin film 32, so that the surface of the photocatalytic thin film 32, that is, the surface of the plasma display panel 100, is kept clean.

The photocatalytic thin film 32 may be made of zinc oxide (ZnO) or a composite oxide containing at least one of titanium and zinc, such as strontium titanate (SrTiO ₃ ), in addition to titanium oxide.

<1-2. Configuration of Phosphor> Photocatalytic Thin Film 32
Since the antifouling action of the PDP operates by the irradiation of ultraviolet rays, it is necessary to irradiate the ultraviolet rays generated inside the plasma display panel 100 with neon (Ne) or xenon (X).
In the discharge using a rare gas such as e), the generated ultraviolet light is ultraviolet light having a wavelength of 200 nm or less, which is called vacuum ultraviolet light. Since the vacuum ultraviolet ray does not pass through the glass, the photocatalytic thin film 3
No ultraviolet light is radiated from the inside to 2.

Then, the vacuum ultraviolet light generated by the rare gas discharge is converted to glass-transmittable ultraviolet light, for example, having a wavelength of 300 nm or more.
A configuration for converting into near-ultraviolet light of 400 nm is required.

In order to convert the vacuum ultraviolet light into near ultraviolet light, the phosphor layer 28 emits near ultraviolet light in response to vacuum ultraviolet light in addition to a normal visible light emitting fluorescent material which receives vacuum ultraviolet light and emits visible light. A near-ultraviolet light-emitting phosphor may be included.

FIG. 2 is a view showing a cross section of the plasma display panel 100 shown in FIG. 1 taken along the line XX, and a region divided by the partition wall 27 and the front substrate 21 is a discharge space 29.
When ultraviolet rays (vacuum ultraviolet rays) generated in the discharge space 29 are irradiated on the phosphor layer 28 containing the near-ultraviolet light emitting phosphor, near ultraviolet rays (UV) and visible light (Light) are radiated. The light will pass through the substrate 21.

FIG. 3 is a schematic diagram showing a light emitting state of the phosphor layer 28 containing a near ultraviolet light emitting phosphor. In FIG. 3, for the sake of clarity, ordinary visible light-emitting phosphor particles 281 are shown in a round shape, and near-ultraviolet light-emitting phosphor particles 282 are shown in a rectangular shape.

As shown in FIG. 3, the vacuum ultraviolet rays (VUV) generated by the plasma discharge are applied to the visible light emitting phosphor particles 281 and the near ultraviolet light emitting phosphor particles 282 to excite the visible light emitting phosphor particles 281 to become visible. Light (Light) is emitted to excite the near-ultraviolet light-emitting phosphor particles 282 to emit near ultraviolet (UV) light. Note that near ultraviolet light may cause visible light to be emitted from the visible light emitting phosphor particles 281 in some cases.

FIG. 4 shows a list of specific examples of near-ultraviolet light-emitting phosphors. FIG. 4 shows the compositions of various near-ultraviolet light-emitting phosphors and their respective peak wavelengths. As shown in FIG. 4, BaSi ₂ O ₅ : P
b ²⁺ (wavelength 350 nm), SrB ₄ O ₇ F: Eu ²⁺ (wavelength 360 nm), (Ba, Sr, Mg) ₃ Si ₂ O ₇ : Pb
²⁺ (wavelength 370 nm), (Ba, Mg, Zn) ₃ Si ₂ O
₇ : Pb ²⁺ (wavelength 295 nm) or the like may be used.

The visible light emitting phosphors are ZnSiO ₄ : Mn ²⁺ for green light emission and (Y, G
d) BO ₃ : Eu ³⁺ , BaMgAl ₁₀ O for emitting blue light
₁₇ : Eu ²⁺ or the like may be used.

<2. Method for Forming Photocatalytic Thin Film> The method for forming the photocatalytic thin film 32 is roughly classified into two methods. One is a physical or chemical film formation method, which is a material for a photocatalytic thin film, for example, an electron beam evaporation method in which titanium oxide is evaporated by an electron beam and deposited on a substrate, a material for a photocatalytic thin film in a high-temperature plasma jet, For example, titanium oxide is added and melted, and a plasma spraying method of spraying the melt onto a substrate, a material for a photocatalytic thin film, for example, a sputtering method for forming a thin film on a substrate by sputtering titanium by ion sputtering, a material for a photocatalytic thin film, for example, titanium (CVD) for growing a thin film by disposing a substrate in a gas containing oxygen and oxygen.

One is a slurry coating method, in which a substance that becomes a photocatalytic thin film, for example, titanium oxide is coated with a particle diameter of 1.
Fine particles of about 30 μm to 30 μm are prepared, mixed with a predetermined solvent, and applied as a slurry.

As a method of applying the slurry, a method is adopted in which only the display surface of the assembled plasma display panel 100 except for the photocatalytic thin film 32 or the entire display surface is immersed in the slurry, pulled up, and then dried. At this time, the thickness of the photocatalytic thin film 32 can be adjusted by adjusting the viscosity of the slurry and the speed of pulling up from the slurry.
The slurry may be applied and printed using a screen printing technique.

The method using the slurry is inexpensive compared with the physical and chemical film forming methods, and can be applied to the plasma display panel 100 after the assembly is completed and the operation test is performed. Therefore, the photocatalytic thin film 32 is prevented from being formed on the malfunctioning plasma display panel 100, and the production yield can be improved.

<3. Modifications> In the above description, it is assumed that the discharge using the rare gas mainly generates vacuum ultraviolet light that does not pass through the glass, and the phosphor layer 28 includes the near ultraviolet light-emitting phosphor that receives the vacuum ultraviolet light and emits near ultraviolet light. Although the configuration in which near-ultraviolet light is generated by discharge has been described, the near-ultraviolet light-emitting phosphor is not necessarily required.

That is, in the case of a plasma of a gas containing a nitrogen gas as a discharge gas, for example, a plasma of a mixed gas of an argon (Ar) gas and a nitrogen (N ₂ ) gas, ultraviolet rays in a wide wavelength range from vacuum ultraviolet to near ultraviolet. , It is not necessary to include a near-ultraviolet light-emitting phosphor. In addition, mercury (H
If the gas contains g), ultraviolet rays having a wavelength of 254 nm will be emitted.

In the above description, the phosphor layer 2
8 shows an example in which the front substrate 21 on which the surface 8 is not applied is the display surface, and the photocatalyst thin film 32 is disposed on the outer surface of the front substrate 21.
Therefore, the substrate on which the phosphor layer 28 is coated can be used as a display surface. In that case, the photocatalytic thin film 32 may be provided on the outer surface of the substrate.

<4. Characteristic Effects> According to the plasma display panel according to the present invention described above, the photocatalytic thin film 32 is provided on the display surface, so that it is generated inside the plasma display panel 100 and passes through the front substrate 21 (glass substrate). UV light is applied to the photocatalytic thin film 32,
Since dust and fine particles composed of organic substances attached to the surface of the photocatalytic thin film 32 are decomposed, even if a filter is attached to the front of the plasma display panel 100, it is not necessary to remove and clean the filter. It is possible to prevent the image quality from being degraded due to particles and fine particles, and to maintain good image display until the operating life of the plasma display panel is reached.

If the discharge inside the plasma display panel is a rare gas discharge, the phosphor layer 28 contains near-ultraviolet light-emitting phosphors that receive vacuum ultraviolet rays and emit near-ultraviolet rays, so that the glass substrate is reduced. Near-ultraviolet light to be transmitted can be obtained, and the antifouling action of the photocatalytic thin film can be exhibited.

Note that, for example, the housing 15 shown in FIG.
The surface of the filter 12 attached to the
(Electromagnetic interference) An ITO film is provided as a countermeasure, and this ITO film has a function as an ultraviolet shielding film in addition to its original function as an electromagnetic wave shielding film. Among the near-ultraviolet rays, the near-ultraviolet rays that did not bring about the antifouling action of the photocatalytic thin film 32 are blocked by the ITO film provided on the filter 12, so that
It is not released outside.

[0046]

According to the plasma display panel of the first aspect of the present invention, a photocatalytic thin film having a photocatalytic action by ultraviolet rays on at least the outer surface of the first and second substrates which is to be the image display surface. Is disposed, if the ultraviolet light generated by the gas discharge or the ultraviolet light generated by the phosphor layer is transmitted through the first and second substrates, dust and fine particles composed of organic matter are deposited on the photocatalytic thin film. Even if it adheres, it is decomposed by the photocatalytic action, preventing the degradation of image quality due to dust and fine particles without cleaning the plasma display panel, and displaying a good image until the operating life of the plasma display panel is reached Can be maintained.

According to the plasma display panel of the second aspect of the present invention, when dust and fine particles composed of organic substances adhere to the photocatalytic thin film, they are decomposed by hydroxyl radicals having a strong oxidizing power, and the surface of the photocatalytic thin film is decomposed. Since it disappears, the surface of the photocatalytic thin film, that is, the surface of the plasma display panel can be maintained in a clean state.

According to the plasma display panel of the third aspect of the present invention, by using titanium oxide or zinc oxide or a double oxide containing at least one of titanium and zinc as the photocatalytic thin film, ultraviolet rays can be obtained. Irradiation can generate hydroxyl radicals on its surface, decompose dust and fine particles composed of organic substances, and maintain the surface of the plasma display panel in a clean state.

According to the plasma display panel of the fourth aspect of the present invention, even if the ultraviolet light generated by the gas discharge has a wavelength that cannot be transmitted through the first and second substrates, the ultraviolet light can be used. The near-ultraviolet light-emitting phosphor converts the near-ultraviolet light to near-ultraviolet light so that the near-ultraviolet light can be transmitted through the first and second substrates.

According to the plasma display panel according to the fifth aspect of the present invention, it is possible to reliably convert ultraviolet light generated by gas discharge into near ultraviolet light that can pass through the first and second substrates.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a configuration of an embodiment of a plasma display panel according to the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of an embodiment of a plasma display panel according to the present invention.

FIG. 3 is a schematic diagram illustrating a light emitting state of a phosphor of the plasma display panel according to the present invention.

FIG. 4 is a diagram showing types of near-ultraviolet light-emitting phosphors.

FIG. 5 is a cross-sectional view illustrating a schematic configuration of a plasma display panel device.

FIG. 6 is a diagram illustrating a problem caused by contact between a filter and a plasma display panel.

[Explanation of symbols]

21 front substrate, 22 rear substrate, 28 phosphor layer, 2
9 Discharge space, 32 photocatalytic thin films.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01J 17/04 H01J 17/04

Claims (5)

[Claims] A second substrate disposed between the first substrate and the first substrate to form a discharge space filled with a discharge gas between the first substrate and the first substrate; And a phosphor layer provided corresponding to the discharge space and mainly generating visible light by ultraviolet rays generated by gas discharge; and at least an outer side of the first and second substrates which is to be an image display surface. A plasma display panel, comprising: a photocatalytic thin film disposed on a surface and having a photocatalytic action by ultraviolet light. 2. The plasma display panel according to claim 1, wherein the photocatalytic thin film is a substance that acts on moisture in the air when irradiated with ultraviolet rays to generate hydroxyl radicals on its surface. 3. The plasma display panel according to claim 2, wherein the photocatalytic thin film is titanium oxide, zinc oxide, or a double oxide containing at least one of titanium and zinc. 4. The phosphor layer includes: a visible light-emitting phosphor that emits visible light in response to ultraviolet light generated by the gas discharge; and near-ultraviolet light emission that emits near ultraviolet light in response to ultraviolet light generated by the gas discharge. 2. A mixture with a phosphor.
The plasma display panel according to claim 3. 5. The phosphor layer, wherein the near-ultraviolet light-emitting phosphor is BaSi ₂ O ₅ : Pb ²⁺ ,
SrB ₄ O ₇ F: Eu ²⁺ , (Ba, Sr, Mg) ₃ Si ₂ O
^{_{7: Pb 2+, (Ba,}} Mg, Zn) 3 Si 2 O 7: Of Pb ^2+, comprising at least one, according to claim 4 plasma display panel according.