JPH10208647A - Plasma display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high efficiency PDP as a result of illumination from not only the phosphor surface but also from its inside by providing a phosphor film formed by mixing a visible region luminescent phosphor for emitting visible rays by means of vacuum ultraviolet rays with an ultraviolet region luminescent phosphor for emitting ultraviolet rays. SOLUTION: A visible region luminescent phosphor to be used as a base is excited by intrinsic vacuum ultraviolet rays to radiate visible rays and also the vacuum ultraviolet rays converted to ultraviolet rays by means of an ultraviolet ray radiating phosphor, and the ultraviolet rays generate visual rays by exciting the visible region phosphor. Accordingly, since the surface of the phosphor radiates principally vacuum ultraviolet rays and the inside of the phosphor radiates principally ultraviolet rays, the luminescent brightness is improved for prescribed input to improve the luminous efficiency, so as to realize a PDP of high efficiency. A visible region luminescent phosphor may be such one as being used for normal PDP. Also, an ultraviolet region luminescent phosphor may be such one as being able to convert vacuum ultraviolet rays to ultraviolet rays of wavelengths shorter than 400nm by rays having wavelengths longer than that.

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 (hereinafter referred to as a PDP) which displays characters, images, and the like by exciting and emitting light from a phosphor applied to a back electrode by vacuum ultraviolet rays radiated by gas discharge. ).

[0002]

2. Description of the Related Art In recent years, flat panel displays have been actively developed. Among them, AC type PDP is
Excellent in display capacity and display quality, response speed, gradation display, etc.

An AC type PDP will be described as an example of a PDP with reference to FIG. FIG. 5 is a perspective view showing the structure of the AC surface discharge type PDP 1, which includes two types of electrodes constituting a display electrode 3 formed in pairs on a front glass substrate 2 and an address electrode 5 formed on a rear glass substrate 4. And said 2
Individual display dots consisting of respective intersections are formed in a matrix on a single glass plate. The display electrode 3 on the front glass side is formed by etching a vapor-deposited transparent conductive film such as ITO in a stripe shape, and the address electrode 5 on the rear glass side is formed by etching a vapor-deposited aluminum film in a stripe shape. I have. A dielectric layer 6 functioning as a capacitor is formed on the display electrode 3, and a protective layer 7 made of MgO is further formed thereon. On the other hand, between the address electrode and the address electrode, a stripe-shaped partition wall 8 is provided by thick film printing, and each display dot is separated and independent. Further, the fluorescent film 9 is applied on the dielectric layer 10 formed on the address electrode and on the side surface of the partition 8, and the inside of the discharge space surrounded by the partition and the front glass substrate does not contain Xe. A mixed gas of an active gas is sealed.

[0004] The display is performed by using AC between the pair of display electrodes.
A cell to be displayed is selected by applying a voltage between an arbitrary address electrode and a display electrode, and by a discharge generated at an intersection of these electrodes. At this time, the wavelength 147n emitted by the Xe glow discharge
The phosphor 9 is excited by vacuum ultraviolet light of m to emit light.

[0005]

The phosphor for a color PDP is, for example, (Y, Gd) BO ₃ : Eu for red.
Zn ₂ SiO ₄ : Mn for green and B for blue
aMgAl ₁₀ O ₁₇ : Eu has been put into practical use.
A cathode ray tube (CR) widely used as a display
There is a problem that the efficiency is lower than that of T). Especially,
The blue phosphor has low efficiency.

Further, when exciting the phosphor with vacuum ultraviolet rays having a wavelength of 147 nm, the energy of the band gap or the fundamental absorption edge of the host crystal of many phosphors is 6 eV or less (wavelength> 200 nm). The possible distance is several hundred angstroms, the light emitting region is almost always limited to the phosphor surface, and the entire phosphor does not contribute to light emission. Therefore, if the inside of the phosphor that does not contribute to light emission can be made to emit light, the luminance of the phosphor improves and the luminous efficiency also improves. For this purpose, ultraviolet light having a long wavelength that can penetrate into the phosphor is effective. If it is an ultraviolet ray having a wavelength in the range of 200 to 400 nm, light is emitted to the inside of the phosphor,
It should be possible to emit light up to the second and third phosphor layers.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide a PDP with higher efficiency than the conventional one by effectively utilizing vacuum ultraviolet rays to emit light not only on the surface but also inside the phosphor.

[0008]

In order to achieve the above object, a PDP of the present invention comprises a visible light emitting phosphor which emits visible light by using vacuum ultraviolet rays and ultraviolet rays having a wavelength longer than the vacuum ultraviolet rays, and a vacuum ultraviolet ray. It is characterized by including a fluorescent film mixed with an ultraviolet light emitting phosphor that emits ultraviolet light having a wavelength longer than vacuum ultraviolet light.

Further, the mixing ratio (weight ratio) of the ultraviolet light emitting phosphor is smaller than the mixing ratio of the visible light emitting phosphor.

The mixing ratio of the ultraviolet light emitting phosphor is 1 to
5% by weight.

Further, the average particle diameter of the visible light emitting phosphor is smaller than the average particle diameter of the ultraviolet light emitting phosphor.

The average particle size of the visible light emitting phosphor is smaller than 4 μm, and the average particle size of the ultraviolet light emitting phosphor is larger than 4 μm.

The ultraviolet light emitting phosphor is LaPO ₄ : C
e and BaSi ₂ O ₅ : Pb and YPO ₄ : Ce.

The visible light emitting phosphor is barium magnesium aluminate activated with a rare earth element, and an ultraviolet light emitting phosphor is mixed with this.

Further, the visible light emitting phosphor BaMgAl ₁₀
It is characterized in that O ₁₇ : Eu is mixed with the ultraviolet light emitting phosphor LaPO ₄ : Ce or BaSi ₂ O ₅ : Pb.

According to the present invention, vacuum ultraviolet rays (147 n
m), by using a phosphor film in which an ultraviolet light emitting phosphor that emits ultraviolet light (for example, 200 to 400 nm) is mixed with a phosphor that emits visible light, the surface of the phosphor emits mainly by vacuum ultraviolet light, Since the inside of the body emits light mainly by ultraviolet rays, the light emission luminance is improved and the light emission efficiency is improved for a given input, so that a highly efficient PDP can be realized.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The PDP of the present invention is based on a visible light-emitting phosphor which emits visible light when excited by vacuum ultraviolet light and ultraviolet light of a longer wavelength. It is characterized by comprising a fluorescent film in which a relatively small amount of an ultraviolet light emitting phosphor that emits ultraviolet light is mixed. The visible light-emitting phosphor emits visible light when excited by the original vacuum ultraviolet light, and the vacuum ultraviolet light is converted into ultraviolet light by the ultraviolet light-emitting phosphor, which also excites the visible light-emitting phosphor to produce visible light. To emit light. For this reason, the PDP of the present invention has characteristics that the luminance is improved and the luminous efficiency is improved as compared with the conventional PDP using only the visible light emitting phosphor.

The visible light emitting phosphor is basically a normal PDP.
Any material can be used as long as it is used. In addition, the ultraviolet light emitting phosphor converts vacuum ultraviolet light into ultraviolet light (corresponding to the ultraviolet excitation spectrum of the visible light emitting phosphor, for example, having a longer wavelength than vacuum ultraviolet light and smaller than a wavelength of about 400 nm). Anything that can be converted can be used.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an AC surface discharge type PDP of the present invention will be described below in detail with reference to the drawings. Figure 1 shows an AC surface discharge type PD
It is a principal part expanded sectional view which shows the cell structure of P. In particular, FIG.
1A shows a cross section of a display electrode, and FIG. 1B shows a cross section of an address electrode.

The PDP of the present invention is manufactured as follows. That is, the address electrodes 5 are formed on the rear glass substrate 4 by aluminum evaporation. Next, the dielectric layer 10 is printed using low melting glass. Similarly, after forming the partition walls 8 using low melting point glass, red is applied to each of the adjacent cells 11, 12, and 13.
Phosphor films 14, 15, and 16 containing phosphors for green and blue are applied and formed above the address electrodes and on the side surfaces of the partition walls. Here, each of the fluorescent films 14, 15, 16 is a visible light emitting phosphor 14a, 15a, 1 that emits visible light by vacuum ultraviolet rays.
6a and an ultraviolet light emitting phosphor 17 that emits ultraviolet light by vacuum ultraviolet light are mixed at a predetermined ratio. In the case of a color PDP, it is formed as described above, but in the case of a monochrome PDP, it is not necessary to paint each color separately. The fluorescent film is formed by screen printing using a liquid obtained by mixing each fluorescent substance and a binder solution such as cyanoethyl cellulose at a predetermined ratio. After the formation of the fluorescent film, baking is performed at about 500 ° C. in order to remove the binder component.

A pair of display electrodes 3 are provided on the front glass substrate 2.
As a transparent conductive film such as ITO. The display electrode is formed only on one glass substrate, and is called a surface discharge type. Next, after the dielectric layer 6 is formed, MgO is used as the protective layer 7.
Is deposited. The protective layer protects the dielectric layer from sputtering by discharge, and also increases the secondary electron emission coefficient and lowers the firing voltage.

Next, the electrodes formed on the front glass substrate and the rear glass substrate are arranged so as to be orthogonal to each other, and frit glass (not shown) is applied to the periphery of the glass substrate. The periphery of both glass substrates is sealed. The inside is evacuated from an exhaust hole (not shown) provided in the rear glass substrate, and after heating and degassing, an inert gas mixed in a predetermined ratio is sealed and the exhaust hole is completely closed. The sealing gas is a 500 Torr He-Ne-Xe mixed gas, and the mixing ratio is 68: 29: 3.

The present invention is characterized by the composition of the fluorescent film, and the other structures and manufacturing steps are the same. Therefore, the description of the manufacturing steps will be omitted in the following description of each embodiment. In addition, each phosphor is listed only the names of representative ones, and an ultraviolet light emitting phosphor that generates ultraviolet light by vacuum ultraviolet light is mixed with a visible light emitting phosphor that generates visible light by vacuum ultraviolet light, and the ultraviolet light is mixed. The present invention includes all phosphors belonging to the technical idea of the present invention in which the visible light emitting phosphor is excited to the inside to emit light.

As an example of the visible light emitting phosphor, BaMgAl ₁₀ O ₁₇ : Eu is used for the blue phosphor 16a, Zn ₂ SiO ₄ : Mn is used for the green phosphor 15a, and the red phosphor 14a is used.
(Y, Gd) BO ₃ : Eu is used for the ultraviolet light emitting phosphor 17, for example, BaSi ₂ O ₅ : Pb, YPO
₄ : Ce, LaPO ₄ : Ce, etc. can be used. In addition,
It goes without saying that any substance that emits ultraviolet rays (for example, wavelengths of 200 to 400 nm) by vacuum ultraviolet rays can be used as the ultraviolet light emitting phosphor.

The measurement results of the composition and the relative luminous efficiency of the phosphor film of each embodiment will be described below.

In Examples 1 to 7, BaMgAl ₁₀ O ₁₇ : Eu having an average particle diameter of 3 μm, a maximum particle diameter of 10 μm, and a minimum particle diameter of 1 μm was used as a visible light emitting phosphor, and an average ultraviolet light emitting phosphor was used. Particle size 10 μm, maximum particle size 30 μm,
BaSi ₂ O ₅ : Pb having a minimum particle size of 2 μm is used.
The mixing ratios of Si ₂ O ₅ : Pb were 2, 3, 4,
The fluorescent film was formed at 5, 10, 25, 50% by weight (wt%).

Next, in Examples 8 to 14, BaMgAl ₁₀ O ₁₇ : Eu having the same average particle size of 3 μm as that used in Examples 1 to 7 was used as the visible light emitting phosphor. LaPO ₄ : Ce having an average particle diameter of 5 μm, a maximum particle diameter of 20 μm, and a minimum particle diameter of 1 μm was used as the ultraviolet light emitting phosphor, and the mixing ratio of LaPO ₄ : Ce was 2, 3, respectively.
The fluorescent film was formed at 4, 5, 10, 25, and 50% by weight.

In Comparative Example 1, 100% by weight of a visible light-emitting phosphor BaMgAl ₁₀ O ₁₇ : Eu having an average particle diameter of 3 μm was used.
It is used to form a fluorescent film.

Next, in Examples 15 to 21, the average particle size was 10 μm and the maximum particle size was 30 μm.
m, the minimum particle size 3μm BaMgAl ₁₀ O _17: using Eu, BaSi the same average particle diameter of 10μm as in Examples 1 to 7 as the ultraviolet region light emitting phosphor ₂ O _5: using Pb, BaSi ₂ The mixing ratio of O ₅ : Pb was 2,
A fluorescent film is formed using 3, 4, 5, 10, 25, and 50% by weight.

Next, in Examples 22 to 28, BaMgAl having the same average particle diameter of 10 μm as those used in Examples 15 to 21 was used as the visible light emitting phosphor.
_{Using 10} O ₁₇ : Eu, the same average particle size of 5 μm as that used in Examples 8 to 14 as the ultraviolet light emitting phosphor was used.
LaPO of m _4: using Ce, LaPO _4: is obtained by forming a fluorescent film mixing ratio of Ce as each 2,3,4,5,10,25,50% by weight.

In Comparative Example 2, 100% by weight of a visible light emitting phosphor BaMgAl ₁₀ O ₁₇ : Eu having an average particle diameter of 10 μm was used.
It is used to form a fluorescent film.

An AC-type PDP on which the fluorescent films of the above Examples and Comparative Examples were respectively formed was manufactured and discharged under a constant driving condition to emit light from the fluorescent films. The luminance is measured by a luminance meter arranged opposite to the front glass substrate 2 of the AC type PDP,
The relative luminance at a constant input, that is, the relative luminous efficiency was obtained. However, the comparative example was set to 100.

Tables 1 and 2 show the relative luminous efficiencies of Examples 1 to 14, and Tables 2 and 3 show the relative luminous efficiencies of Examples 15 to 28.

[0034]

[Table 1]

[0035]

[Table 2]

The following can be understood from these results. That is, when a small amount of the ultraviolet light emitting phosphor is mixed with the visible light emitting phosphor, the luminous efficiency is remarkably improved. The mixing ratio at which the luminous efficiency is improved differs depending on the average particle size, the type of the ultraviolet light emitting phosphor, and the like. For example, the visible light emitting phosphor is BaMgAl ₁₀ O ₁₇ : E having an average particle size of 3 μm.
In the case of u, the luminous efficiency is improved with LaPO ₄ : Ce of about 14 wt% or less and BaSi ₂ O ₅ : Pb of 6 wt% or less, and particularly, 2 to 8 w in LaPO ₄ : Ce.
In the range of t%, 1 to 5 wt% for BaSi ₂ O ₅ : Pb.
%, High luminous efficiency can be obtained. When the visible light emitting phosphor has an average particle diameter of 10 μm, the luminous efficiency is improved at about 7 wt% or less, but the effect is smaller than when the average particle diameter is 3 μm. Further, LaPO ₄ : Ce is used instead of BaSi ₂ O ₅ : Pb.
Is more effective. When the average particle diameter of the visible light emitting phosphor as the main component is smaller, for example, 3 μm than 10 μm, the effect of improving the luminous efficiency by mixing the ultraviolet light emitting phosphor is greater.

As described above, it is not clear why the luminous efficiency increases when a small amount of the ultraviolet light emitting phosphor is mixed, and the luminous efficiency decreases as the mixing ratio increases.
The following explanation is possible. That is, as the visible light emitting phosphor is mixed with the ultraviolet light emitting phosphor, the ultraviolet light emitting phosphor absorbs the vacuum ultraviolet rays and has a wavelength of 200 to 200, for example.
Ultraviolet light of 400 nm is generated, and this ultraviolet light penetrates into the visible light emitting phosphor to efficiently emit visible light, so that the emission intensity increases as shown by curve A in FIG.
However, when the mixing ratio increases, the amount of vacuum ultraviolet light reaching the visible light emitting phosphor decreases due to the shielding effect of the vacuum ultraviolet light by the ultraviolet light emitting phosphor, and the light emission intensity is gradually saturated.

On the other hand, since the absolute amount of the visible light emitting phosphor decreases as the mixing ratio of the ultraviolet light emitting phosphor increases, the luminous intensity of the visible light emitting phosphor due to the vacuum ultraviolet ray is as shown by the curve B in FIG. Decreasing. When the curves A and B are combined, a curve C in which a peak occurs in a range where the mixing ratio is small is obtained.

FIGS. 2 and 3 show that when the average particle size of the visible light emitting phosphor is smaller than that of the ultraviolet light emitting phosphor, the luminous efficiency is significantly improved. This can be explained as follows. In other words, since the visible light-emitting phosphor having a small particle diameter covers the surface of the ultraviolet light-emitting phosphor having a large particle diameter, the ultraviolet light emitted from the ultraviolet light-emitting phosphor is visible without being greatly reduced in the middle. The phosphor reaches the area light-emitting phosphor, and sufficiently penetrates into the visible area light-emitting phosphor having a small particle size, and excites the phosphor to emit light efficiently. As a result, the boundary between the desirable average particle size of the visible light emitting phosphor and the ultraviolet light emitting phosphor is 3 μm and 5 μm.
m, it can be estimated to be about 4 μm.

Based on the above experimental results, the PD of the present invention
P is characterized by significantly improving the luminous efficiency by providing a phosphor film in which the conventional visible light emitting phosphor is mixed with the ultraviolet light emitting phosphor at a smaller weight ratio than the visible light emitting phosphor. .

In the above embodiment, blue-emitting BaMgAl ₁₀ O ₁₇ : Eu is used as the visible light emitting phosphor, and BaSi ₂ O ₅ : Pb, LaPO is used as the ultraviolet light emitting phosphor.
₄ : Although an example using Ce has been described, it is not limited to these materials. For example, as the visible light emitting phosphor, another blue light emitting phosphor, CaWO ₄ : P
b, Y ₂ SiO ₅ : Ce, BaMgAl ₁₄ O ₂₃ : Eu, etc., or a red light-emitting phosphor Y ₂ O ₃ : Eu,
Y ₂ SiO ₅ : Eu, Y ₃ Al ₅ O ₁₂ : Eu, YBO
₃ : Eu, GdBO ₃ : Eu, ScBO ₃ : Eu, Lu
BO ₃ : Eu or the like, or a green light-emitting phosphor Z
n ₂ SiO ₄ : Mn, BaAl ₁₂ O ₁₉ : Mn, BaMg
_{AL 14 O 23: Mn, SrAl} 12 O 19: Mn, ZnAl 12
O ₁₉ : Mn, C, aAl ₁₂ O ₁₉ : Mn, YBO ₃ : T
b, LuBO ₃ : Tb, GdBO ₃ : Tb, ScBO
₃ : Tb, Sr ₄ SiO ₈ Cl ₄ : Eu, etc.
Any phosphor capable of emitting visible light by vacuum ultraviolet light and ultraviolet light can be used as the visible light emitting phosphor of the present invention.

The ultraviolet light emitting phosphor is the aforementioned BaSi
_{2 O 5: Pb, LaPO 4} : addition of Ce, YPO _4: C
e or another thing. Any material that emits ultraviolet light having a wavelength that can excite the visible light emitting phosphor can be used alone or in combination of two or more.

The effective mixing ratio of the ultraviolet light emitting phosphor varies depending on the kind, combination, particle size, etc. of the phosphor material. However, if the mixing ratio is large, the ratio of the visible light emitting phosphor itself decreases and the emission intensity decreases. Therefore, the mixing ratio of the ultraviolet light emitting phosphor should be smaller than that of the visible light emitting phosphor, and a particularly desirable range is 1 to 5 wt%.

Regarding the average particle diameter of the phosphor, the smaller the average particle diameter of the visible light-emitting phosphor than the average particle diameter of the ultraviolet light-emitting phosphor is, in any case, larger. Luminous efficiency is higher than that, which is desirable.

The AC surface discharge type PDP has been described above. However, the present invention is not limited to the AC surface discharge type, but the PDP using a vacuum ultraviolet ray and a phosphor emitting visible light by ultraviolet rays such as an AC facing discharge type and a DC type. Needless to say, the present invention can be applied to any system.

[0046]

The PDP of the present invention has a phosphor film in which a visible light emitting phosphor that emits visible light by vacuum ultraviolet light and ultraviolet light and an ultraviolet light emitting phosphor that emits ultraviolet light by vacuum ultraviolet light are mixed. Because the visible light emitting phosphor is vacuum ultraviolet light and ultraviolet light (the ultraviolet light emitting phosphor emits light)
, And efficiently emits visible light, so that a PDP with high luminous efficiency can be provided.

[Brief description of the drawings]

FIG. 1 shows an AC surface discharge type PDP showing one embodiment of the present invention.
Main part enlarged sectional view of

FIG. 2 is a diagram showing the relationship between the mixing ratio of the ultraviolet light emitting phosphor according to the present invention and the relative luminous efficiency.

FIG. 3 is a diagram showing the relationship between the mixing ratio of the ultraviolet light emitting phosphor according to the present invention and the relative luminous efficiency.

FIG. 4 is a diagram for explaining a peak of relative luminous efficiency.

FIG. 5 is a perspective view showing an example of a conventional AC surface discharge type PDP.

[Explanation of symbols]

 14, 15, 16 phosphor film 14a, 15a, 16a visible light emitting phosphor 17 ultraviolet light emitting phosphor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01J 11/02 H01J 11/02 Z

Claims (8)

[Claims] 1. A plasma display panel comprising a phosphor film in which a visible light emitting phosphor that emits visible light by vacuum ultraviolet rays and an ultraviolet light emitting phosphor that emits ultraviolet rays are mixed. 2. The plasma display panel according to claim 1, wherein a mixing ratio (weight ratio) of the ultraviolet light emitting phosphor is smaller than a mixing ratio of the visible light emitting phosphor. 3. The plasma display panel according to claim 2, wherein the mixing ratio of the ultraviolet light emitting phosphor is 1 to 5% by weight. 4. The plasma display panel according to claim 1, wherein the average particle diameter of the visible light emitting phosphor is smaller than the average particle diameter of the ultraviolet light emitting phosphor. 5. The plasma display panel according to claim 4, wherein an average particle diameter of the visible light emitting phosphor is smaller than 4 μm, and an average particle diameter of the ultraviolet light emitting phosphor is larger than 4 μm. 6. The plasma display according to claim 1, wherein the ultraviolet light emitting phosphor is at least one member selected from the group consisting of LaPO ₄ : Ce, BaSi ₂ O ₅ : Pb and YPO ₄ : Ce. panel. 7. The plasma display panel according to claim 1, wherein the visible light emitting phosphor is barium magnesium aluminate activated with a rare earth element. 8. The visible light emitting phosphor is BaMgAl ₁₀ O ₁₇ :
_2. The plasma display panel according to claim 1, wherein the plasma display panel is Eu, and the ultraviolet light emitting phosphor is LaPO ₄ : Ce or BASi ₂ O ₅ : Pb.