JPH1167103A - Plasma display panel - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To suppress deterioration with time of luminance of a phosphor layer of a PDP. SOLUTION: At least two kinds of phosphors, a first phosphor for converting vacuum ultraviolet rays into radiation having a longer wavelength than the vacuum ultraviolet rays, and a second phosphor for converting the converted radiation into visible light, are used. The above object is achieved by a plasma display panel having a phosphor layer containing the same.

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).

[0002]

2. Description of the Related Art A PDP generally comprises a pair of opposed components such as a substrate, electrodes, partition walls, a phosphor layer, and a discharge gas. Further, a discharge space is defined by the pair of substrates and the partition walls, and a phosphor layer and a discharge gas are present in the discharge space.
He, Ne, Ar, and Xe are known as the discharge gas, and among them, Xe that generates vacuum ultraviolet rays having the highest excitation efficiency for the phosphor is mainly used, and the display is performed from the Xe discharge gas. This is performed by converting vacuum ultraviolet light such as a generated resonance line (147 nm) or a molecular beam (172 nm) into visible light by a phosphor in a phosphor layer.

In the case of a color PDP, three kinds of phosphors capable of converting vacuum ultraviolet rays into red, green and blue visible lights are used.

[0004]

Conventionally, vacuum ultraviolet rays used for display have a large photon energy. Therefore, when irradiating the phosphor layer, the phosphor contained in the phosphor layer is destroyed and lattice defects and the like are generated. May occur. Further, when the phosphor layer is irradiated with vacuum ultraviolet rays for a longer period of time, deterioration over time such as deterioration in luminance and change in chromaticity has occurred.

[0005] This deterioration with time is caused by a blue or green manganese (may contain europium) activated europium activated barium, magnesium or aluminum oxide having relatively small binding energy as a phosphor. It was noticeable in the phosphor layer using the phosphor. In order to prevent this deterioration with time, it is conceivable to use a gas capable of generating ultraviolet light having a photon energy of 250 nm or more, which is smaller than vacuum ultraviolet light, as the discharge gas.
This was not possible with DP.

[0006] Further, since the vacuum ultraviolet ray has a large photon energy, it cannot pass through the phosphor existing on the surface of the phosphor layer. That is, only the phosphor existing on the surface of the phosphor layer contributed to light emission, and the phosphor existing inside (deep portion) did not contribute to light emission. Therefore,
Deterioration of only the phosphor existing on the surface of the phosphor layer causes a large deterioration in luminance.

Further, plasma generated by the discharge gas is
Since it is near the phosphor layer, the surface of the phosphor layer is sputtered by the plasma, and the phosphor may be further deteriorated.

[0008]

SUMMARY OF THE INVENTION The present inventor of the present invention has found that, even with a phosphor degraded by irradiation with vacuum ultraviolet rays, it cannot be exposed to ordinary ultraviolet rays (254 nm) generated from mercury vapor used in a phosphor lamp or the like. The inventors have found that the above problem can be solved by temporarily converting vacuum ultraviolet light into ultraviolet light having a longer wavelength than vacuum ultraviolet light because the deterioration is hardly caused.

Further, the inventors of the present invention have reported that the vacuum ultraviolet light is
Since the phosphor existing on the surface of the phosphor layer cannot be transmitted therethrough, it has been found that by effectively using the phosphor existing inside the phosphor layer (deep portion), the deterioration of the phosphor layer over time can be suppressed. ing. Thus, according to the present invention, at least two kinds of phosphors, a first phosphor that converts vacuum ultraviolet rays into radiation having a wavelength longer than that of the vacuum ultraviolet rays and a second phosphor that converts the converted radiation into visible light. A plasma display panel having a phosphor layer containing a phosphor is provided. At this time, the first phosphor is
Must be a phosphor that is more resistant to degradation (has a relatively large binding energy) than the phosphor of (1).

Further, according to the present invention, a phosphor layer containing at least two kinds of phosphors, ie, a third phosphor for converting vacuum ultraviolet light into visible light and a fourth phosphor for converting infrared light into visible light. A plasma display panel having the following is provided.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, the phosphor layer of the present invention contains the following phosphors: a first phosphor that converts vacuum ultraviolet rays into radiation having a longer wavelength than the vacuum ultraviolet rays; A second phosphor that converts the converted radiation into visible light, a third phosphor that converts vacuum ultraviolet light into visible light, and a fourth phosphor that converts infrared light into visible light.

First, the case will be described. It is known that a conventionally used phosphor has a potential difference between a valence band and a conduction band of about 5 eV. Here, since the vacuum ultraviolet ray has a large photon energy of about 8.3 eV, it cannot be transmitted from the surface of the phosphor layer to the inside. Therefore, only the surface of the phosphor layer contributes to light emission. On the other hand, light in a longer wavelength region than vacuum ultraviolet light has smaller photon energy than vacuum ultraviolet light, for example,
In the ultraviolet region between vacuum ultraviolet light and visible light, the photon energy is about 4 eV. Accordingly, the photon energy is lower than the potential difference of the phosphor layer, and light in this region can pass through the phosphor layer. In other words, if light emission in a region having a wavelength longer than that of vacuum ultraviolet light is effectively used, deterioration of luminance over time can be suppressed.

The first phosphor is not particularly limited as long as it can convert vacuum ultraviolet rays into radiation having a longer wavelength than the vacuum ultraviolet rays. Therefore, a phosphor that emits light only by irradiation with vacuum ultraviolet rays and does not emit light when irradiated with radiation in a region other than vacuum ultraviolet rays is included. Here, the radiation having a wavelength longer than the vacuum ultraviolet ray means that it includes all wavelength regions longer than the vacuum ultraviolet ray (wavelength of 190 nm or less) (that is, wavelengths longer than 190 nm). In the present invention, the wavelength region between vacuum ultraviolet light and visible light (that is, 190 to 390 n)
It is preferable to use a phosphor that can be converted to the radiation of m) because a decrease in luminous efficiency can be suppressed. Particularly preferably 250 to 400 nm, more preferably 320 to 350 nm
It is a phosphor that can be converted into radiation having a peak wavelength of nm.

As a specific phosphor, BaSi
_TwoO_Five: Pb (351 nm), (Ba, Sr, Mg)_Three
Si_TwoO₇: Pb (372 nm), SrB_FourO₇: Eu
(368 nm), (Ca, Zn)_Three(PO_Four)_Two: Tl
(306 nm), YPO_Four: Ce (357 nm), La
PO_Four: Ce (318 nm), Ce (Mg, Ba) Al
₁₁O ₁₉(348 nm), (Ce, Ba) MgAl₁₁O₁₉
(354 nm). These phosphors are combined
(The peak wavelength after conversion is shown in parentheses.)
Means).

Next, as the second phosphor, any phosphor can be used as long as the radiation converted by the first phosphor can be converted into visible light. . For example, any of the phosphors used in the art can be used. More specifically, Y ₂
O ₃ : Eu, YVO ₄ : Eu, (Y, Gd) BO ₃ : E
u, Y ₂ O ₃ S: Eu, γ-Zn ₃ (PO ₄ ) ₂ : M
n, (Zn, Cd) S: Ag (more than red), Zn ₂ Ge
O ₂ : Mn, BaAl ₁₂ O ₁₉ : Mn, Zn ₂ SiO ₄ :
_{Mn, LaPO 4: Tb, ZnS} : (Cu, Al), Z
nS: (Au, Cu, Al), (Zn, Cd) S: (C
u, Al), Zn ₂ SiO ₄ : (Mn, As), Y ₃ A
l ₅ O ₁₂ : Ce, Gd ₂ O ₂ S: Tb, Y ₃ Al
₅ O ₁₂ : Tb, ZnO: Zn (green above), Sr ₅ (P
O ₄ ) ₃ Cl: Eu, BaMgAl ₁₄ O ₂₃ : Eu, Ba
MgAl ₁₆ O ₂₇ : Eu, BaMgAl ₁₀ O ₁₇ : Eu, Z
nS: Ag, Y ₂ SiO ₃ : Ce (above, blue) and the like.

Since these second phosphors often have a higher emission intensity in the region between the vacuum ultraviolet ray and the visible light than in the vacuum ultraviolet ray, the second phosphor has the same structure as the first phosphor. By combining the second phosphor, it is possible to improve luminance and suppress deterioration with time. These phosphors may be used in combination. Among the second phosphors, the phosphor that converts ultraviolet light into blue light generally has a weak bonding force and is particularly greatly deteriorated by the discharge gas. Therefore, the effect of suppressing deterioration over time according to the present invention can be obtained more. For example, FIG. 1 shows an excitation spectrum showing a change in emission intensity at each excitation wavelength immediately after the production of a PDP using KX-501A manufactured by Kasei Optonix as a phosphor for converting ultraviolet light into blue, and after display for 2,000 hours. As can be seen from FIG.
The emission intensity after 2,000 hours of display is particularly degraded in the vacuum ultraviolet region. However, there is almost no deterioration in the ultraviolet region from visible light to vacuum ultraviolet light. Therefore, by effectively utilizing the ultraviolet rays in this region, it is possible to prevent the luminance from deteriorating with time.

The phosphor layer of the present invention may have any configuration as long as the first phosphor is exposed on the surface. For example, there is a configuration in which a first phosphor and a second phosphor are uniformly mixed, and a configuration in which the second phosphor is covered with the first phosphor. Among them, a configuration in which the second phosphor is covered with the first phosphor is preferable because deterioration of the first phosphor due to the discharge gas can be prevented.

The first phosphor is preferably contained in an amount of 1 to 70% by weight based on the whole phosphor layer. 1% by weight
If the amount is smaller than that, it is difficult to convert the vacuum ultraviolet ray, so that it does not contribute to the suppression of the deterioration with time of the luminance. If the content is more than 70% by weight, the amount of the phosphor that converts to visible light decreases, and the luminance decreases, which is not preferable. When these phosphors are mixed, the effect of deterioration with time is reduced, but the number of manufacturing steps is not increased.

Further, a phosphor (fourth phosphor) for converting infrared rays into visible light described below may be included. It is preferable that the phosphor is not exposed on the surface of the phosphor layer but is present inside. Next, the case will be described. It is generally known that a discharge gas such as Xe emits light not only in the vacuum ultraviolet region but also in the infrared region. In the case of (1), light emission in the infrared region is to be used effectively.

First, a third method for converting vacuum ultraviolet light into visible light is described.
The same phosphor as the second phosphor in the above case can be used. On the other hand, as the fourth phosphor,
There is no particular limitation as long as it is a phosphor that can convert infrared light into visible light. Specifically, Y _0.74 Yb _0.25 E
r _0.01 OCl (more than red), Y _0.84 Yb _0.15 Er _0.01 F
₃ , NaY _0.69 Yb _0.30 Er _0.01 F ₄ , BaY _1.34 Yb
_0.60 Er _0.06 F ₈ (green above), Y _0.65 Yb _0.35 Tm
_0.001 F ₃ (all blue). These phosphors may be used in combination.

The phosphor layer of the present invention may have any configuration as long as the third phosphor is exposed on the surface. For example, a configuration in which the third phosphor and the fourth phosphor are uniformly mixed, and a configuration in which the fourth phosphor is covered with the third phosphor are exemplified. Among them, the configuration in which the fourth phosphor is covered with the third phosphor is preferable because the irradiation light in the ultraviolet region and the infrared region of the discharge gas can be effectively converted into visible light.

The phosphor layer of the present invention can be formed by applying a paste containing a phosphor to a desired portion and then firing the paste. Here, a resin, a solvent, or the like may be added to the paste for adjusting the viscosity. As a resin that can be used, any resin known in the art can be used. Specific examples include ethyl cellulose, nitrocellulose, acrylic resin, polyvinyl alcohol, and the like, and may further include a photosensitive resin. On the other hand, examples of the solvent include alcohols, terpineol, butyl carbitol acetate (BCA), butyl carbitol, toluene, butyl acetate and the like.

The paste is applied on the phosphor layer forming surface by a known method such as a screen printing method, a doctor blade method, a slot coater method, and a bar coater method.
Thereafter, the applied paste is fired to form a phosphor layer. When a paste containing a photosensitive resin is used, a phosphor layer can be formed in a desired region by applying, exposing, developing, and firing.

Next, an example of the PDP having the phosphor layer of the present invention will be described with reference to FIG. Note that the configuration in FIG. 2 is an example, and the present invention is not limited to this, and can be applied to any type of PDP such as an AC type or a DC type as long as the PDP has a phosphor layer. it can. FIG.
Is a general indirect discharge type (AC type) surface discharge type PDP
FIG. 3 is a schematic perspective view corresponding to one pixel, and shows a PDP that belongs to the reflection type and has a three-electrode structure when classified according to the arrangement of the phosphor layers.

In the PDP 1 shown in FIG. 2, a pair of substrates 2 and 5 are arranged to face each other. As the substrate, a glass substrate, a quartz substrate, a silicon substrate, or the like can be used. A pair of display electrodes (sustain electrodes) X and Y are formed in parallel on the substrate 2, and a dielectric for alternating current (AC) driving a discharge by wall electrodes on the substrate 2 so as to cover the display electrodes X and Y. A body layer 3 is formed, and a protective film 4 is further formed on the dielectric layer 3. The dielectric layer can be generally formed by applying and firing a low-melting glass paste.
The protective film is generally made of MgO or the like.

On the other hand, a plurality of stripe-shaped address electrodes A are formed on the substrate 5 at positions orthogonal to the display electrodes X and Y in a plan view, and a dielectric is formed on the substrate 5 so as to cover the address electrodes A. The body layer 6 is laminated. Here, the address electrode is made of Ag, Au, Al, Cu, Cr, a laminate thereof (for example, Cr / Cu / Cr), or the like, and is formed by combining a film forming method such as a sputtering method and a vapor deposition method with an etching method. , A desired number, thickness, width and spacing.

Further, a plurality of stripe-shaped barrier ribs 7 are formed between adjacent address electrodes A and in parallel with the address electrodes A. The partition walls 7 can be formed by a sand blast method, a printing method, a photo etching method, or the like. Next, the phosphor layer 8 is formed on the side surface of the adjacent partition wall 7 and on the address electrode A. Next, reference numeral 9 denotes a discharge space, which is defined for each unit light emitting region (hereinafter, EU) in the extending direction of the display electrodes X and Y, and defines a gap size. A desired discharge gas is sealed in the discharge space 9.

In the PDP 1, as shown in FIG. 2, in each of three EUs corresponding to one pixel, a selected discharge cell for selecting display or non-display at the intersection of the display electrode Y and the address electrode A is determined. Have been. Also, the display electrode X
And Y, a main discharge cell is defined. Here, the phosphor layer 8 is formed of a partition wall 7 on the substrate 5 opposite to the display electrodes X and Y in order to avoid impact due to ions generated by surface discharge.
It is provided between them. The phosphor layer 8 converts vacuum ultraviolet rays generated by surface discharge of the main discharge cells into radiation having a longer wavelength than vacuum ultraviolet rays, and converts the radiation into visible light or converts vacuum ultraviolet and infrared light into visible light. It emits light by doing. The light emitted by the phosphor layer 8 passes through the dielectric layer 3 and the substrate 2 and is emitted to the outside. That is,
In the PDP 1, the outer surface of the substrate 2 becomes the display surface D.

Since the display electrodes X and Y are arranged on the display surface D side with respect to the phosphor layer 8, a wide transparent electrode is used in order to widen the surface discharge and minimize the shielding of the display light. It is composed of a conductive film 10 and a narrow metal film (bus electrode) 11 for supplementing its conductivity. The transparent conductive film is made of, for example, a metal oxide such as ITO (indium oxide + tin oxide) or nesa (tin oxide), and has a desired number, thickness, and width by combining a film forming method such as evaporation and an etching method. And at intervals. On the other hand, the bus electrode is made of Ag, Au, Al, Cu, Cr, a laminate thereof (for example, Cr / Cu / Cr), or the like, and is formed by combining a film forming method such as a sputtering method and a vapor deposition method with an etching method. , A desired number, thickness, width and spacing.

As described above, the PDP 1 covers the display electrodes X and Y and has the substrate 2 having the dielectric layer 3 for maintaining discharge.
(A front substrate) and a substrate 5 (a rear substrate) having a partition 7 for partitioning the discharge space 9.

[0031]

【Example】

Example 1 Among three color phosphors for PDP, a phosphor (BaMgAl ₁₀ O ₁₇ : E) that converts ultraviolet rays, which are most likely to deteriorate with time, into blue.
u, trade name KX-501A: manufactured by Kasei Optonix) and a phosphor (LaPO ₃ : Ce, trade name: NP-806: manufactured by Nichia Corporation) that converts vacuum ultraviolet light into ultraviolet light having a longer wavelength than the vacuum ultraviolet light. A paste containing a phosphor consisting of The phosphor that converts vacuum ultraviolet light into ultraviolet light having a wavelength longer than that of the vacuum ultraviolet light is contained at 1% by weight based on the entire phosphor. The viscosity of the paste was adjusted with a solvent so that the paste could be applied. Using this paste, about 2
A phosphor layer of 0 μm is formed,
A PDP was prepared as shown in FIG. In addition, the obtained PDP
Was a 21-inch type for displaying blue. Obtained PD
P was displayed for 2000 hours, and the luminance retention ratio after 2000 hours was measured. The results are shown in Table 1. Note that the luminance maintenance ratio means a luminance reduction ratio when the initial luminance is set to 100.

Examples 2 to 7 5% by weight (Example 2), 10% by weight (Example 3), and 20% by weight (Example 4) of phosphors for converting vacuum ultraviolet light into ultraviolet light having a wavelength longer than the vacuum ultraviolet light ), 50% by weight (Example 5), 70% by weight (Example 6), and 80% by weight (Example 7) in the same manner as in Example 1
Was prepared, and the luminance maintenance ratio was measured. The results are shown in Table 1.

Example 8 A phosphor that converts infrared light into blue light (Y _0.65 Yb _0.35 Tm
A lower phosphor layer of about 15 μm is formed using a paste containing _0.001 F ₃ ), and a phosphor (BaMgAl ₁₀ O ₁₇ : Eu, trade name: KX-50) for converting ultraviolet light into blue is formed thereon.
1A: A PDP was produced in the same manner as in Example 1 except that an upper phosphor layer of about 5 μm was formed using a paste containing a chemical compound (manufactured by Kasei Optonics Co., Ltd.), and the luminance retention ratio was measured. The results are shown in Table 1.

Example 9 A phosphor (BaMgAl ₁₀ O ₁₇ :
Eu, trade name KX-501A: manufactured by Kasei Optonics Co., Ltd.)
A phosphor (LaPO ₃ : Ce, trade name: NP) that converts 90 parts by weight and vacuum ultraviolet light into ultraviolet light having a longer wavelength than the vacuum ultraviolet light
-806: manufactured by Nichia Corporation) A PDP was prepared in the same manner as in Example 8 except that an upper phosphor layer was prepared using a paste containing a phosphor consisting of 10% by weight, and luminance was maintained. The rate was measured. The results are shown in Table 1.

COMPARATIVE EXAMPLE 1 A phosphor (BaMgAl ₁₀ O ₁₇ ) that converts ultraviolet light into blue light
Eu, trade name KX-501A: manufactured by Kasei Optonics Co., Ltd.)
A PDP was prepared in the same manner as in Example 1 except that a phosphor layer was prepared using a paste made of, and the luminance retention ratio was measured. The results are shown in Table 1.

[0036]

[Table 1] In Table 1, the blue phosphor means a phosphor that converts ultraviolet light into blue, the ultraviolet phosphor means a phosphor that converts vacuum ultraviolet light into ultraviolet light having a longer wavelength than the vacuum ultraviolet light, and the infrared phosphor emits infrared light. It means a phosphor that converts to blue. As is clear from Table 1, phosphors that convert ultraviolet light into blue light
By adding a phosphor that converts vacuum ultraviolet light into ultraviolet light having a wavelength longer than that of the vacuum ultraviolet light and / or a phosphor that converts infrared light into blue light, the luminance retention ratio could be improved.

[0037]

According to the PDP of the present invention, there are provided a phosphor for converting ultraviolet rays into blue, a phosphor for converting vacuum ultraviolet rays into ultraviolet rays having a wavelength longer than the vacuum ultraviolet rays, and / or a phosphor for converting infrared rays into blue. Because it has a phosphor layer with
It is possible to prevent the luminance from deteriorating with time. This makes it possible to prevent image burn-in when, for example, displaying the same screen (fixed display).

[Brief description of the drawings]

FIG. 1 is an excitation spectrum showing changes in emission intensity for each excitation wavelength immediately after PDP production and after display for 2,000 hours.

FIG. 2 is a schematic perspective view of a PDP of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PDP 2, 5 Substrate 3, 6 Dielectric layer 4 Protective film 7 Partition wall 8 Phosphor layer 9 Discharge space 10 Transparent conductive film 11 Metal film A Address electrode D Display surface X, Y display electrode

Claims (6)

[Claims] At least two kinds of phosphors, a first phosphor for converting vacuum ultraviolet rays into radiation having a wavelength longer than that of the vacuum ultraviolet rays, and a second phosphor for converting the converted radiation into visible light. A plasma display panel comprising a phosphor layer containing: 2. The plasma display panel according to claim 1, wherein the radiation has a peak wavelength of 250 to 400 nm. 3. The plasma display panel according to claim 1, wherein the first phosphor is contained in an amount of 1 to 70% by weight based on the entire phosphor layer. 4. The plasma according to claim 1, wherein the phosphor layer has a two-layer structure of an upper layer and a lower layer, wherein the upper layer comprises a first phosphor, and the lower layer comprises a second phosphor. Display panel. 5. A phosphor layer comprising at least two phosphors, a third phosphor that converts vacuum ultraviolet light into visible light and a fourth phosphor that converts infrared light into visible light. Plasma display panel. 6. The plasma display panel according to claim 5, wherein the phosphor layer has a two-layer structure of an upper layer and a lower layer, wherein the upper layer comprises a third phosphor and the lower layer comprises a fourth phosphor.