JPH11131059A - Fluorescent layer and display device having the layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fluorescent layer capable of absorbing light excluding the wavelength range of the light emitted by the fluorescent material and developing high contrast and useful for a plasma display, etc., by using a specific light-emitting particle in combination with a specific light-absorbing material. SOLUTION: This fluorescent layer contains (A) a fluorescent particle emitting visible light by the excitation with ultraviolet rays having a wavelength of <=200 nm and (B) a material having a light-absorbing power in a wavelength range other than the wavelength of the visible light emitted by the component A (e.g. Fe2 O3 absorbing green and blue light, ZnO/TiO2 /NiO/CoO absorbing red and blue light or CoO/Al2 O3 absorbing red and green light). The fluorescent layer preferably contains <=5 wt.% of the component B based on the component A. The fluorescent layer is formed in a state containing the fine particles of the component B attached to the surface of the component A or mixed in the space between the particles of the component A e.g. by mixing the component A, the component B and a vehicle to obtain a paste, applying the paste to a desired part by screen printing and drying and baking the applied paste.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phosphor layer excited by rare gas resonance ultraviolet rays (so-called vacuum ultraviolet rays) having a wavelength of 200 nm or less, a flat-type plasma display having the phosphor layer, a rare gas discharge lamp, and the like. Related to a display device.

[0002]

2. Description of the Related Art In a plasma display, short-wavelength ultraviolet rays generated in a negative quorum region in a minute discharge space containing a rare gas in a display panel (when xenon is used as a rare gas, the resonance line becomes 147 nm or 172 nm). is there)
This is a method of performing color display by causing a phosphor disposed in a discharge space to emit light by using the light as an excitation source. The structure of this gas discharge cell is, for example, “Color PDP technology and materials” /
And the typical structure is shown in FIGS.

In a display panel of a plasma display,
A rare gas resonance line having a wavelength shorter than the mercury vapor resonance line of 253.7 nm is used as an excitation source of the phosphor, and its short wavelength limit is a helium resonance line of 58.4 nm. FIG. 3 is a sectional view showing the structure of a display panel of a general surface discharge type color plasma display. The front substrate glass and the rear substrate glass made of a glass substrate are bonded and integrated, and this figure shows a cross-sectional structure of a portion corresponding to one pixel.
9 shows a reflective display panel in which a phosphor layer is formed on the back substrate side. The front substrate is formed of a pair of display electrodes and a dielectric layer for AC driving on the pair of display electrodes, which are formed in parallel at a predetermined distance on a surface facing the rear substrate. The rear substrate partitions an electrode group composed of address electrodes orthogonal to the display electrode group of the front substrate on an opposing surface with the front substrate, and an address electrode for preventing discharge from spreading (defining a discharge area). Partition walls (ribs) made of low-melting glass, and respective fluorescent lights that emit red (R), green (G), and blue (B) sequentially painted in stripes to cover the groove surfaces between the ribs It is composed of body layers. This phosphor layer is formed by mixing phosphor particles and a vehicle to form a phosphor paste, forming an address electrode and a partition on the rear substrate, forming the screen by a method such as screen printing, and removing volatile components by firing. I do.

In a discharge space between the front substrate and the rear substrate, a discharge gas (mixed gas such as neon, xenon, etc.) is enclosed, and discharge is performed between display electrodes including X and Y sustain electrodes to perform address discharge. Excites the phosphor layer in the unit light-emitting region (discharge spot) selected by the above with the vacuum ultraviolet rays generated by the gas discharge to obtain visible light emission. Then, a color display is obtained by combining the light emission amounts of the unit light emitting regions having the red, green, and blue phosphor layers corresponding to the three primary colors.

[0005]

At present, the brightness of a display panel of a plasma display, especially a color panel, has been improving year by year (up to 450 cd / m ² ), but that of a direct-view type electron tube color TV (peak brightness 600 μm). Cd1000 cd / m ² ), and it is desired to improve characteristics such as luminous efficiency. With this luminance, it is not possible to obtain a sufficient display contrast in a bright field that affects the image quality, and there is a strong demand for the development of a contrast improvement method that does not affect the luminance characteristics. Especially,
In a region where the display panel resolution exceeds VGA, the cell size is reduced and the light emission efficiency of the display panel is reduced, so that the luminance is reduced and the reduction in contrast becomes a serious problem.

An object of the present invention is to provide a phosphor layer capable of obtaining high contrast and a display device such as a plasma display provided with a display panel using the phosphor layer.

[0007]

The above object is achieved at a wavelength of 200 nm.
This can be achieved by the following phosphor particles that emit visible light upon excitation of ultraviolet light, and a phosphor layer containing a material having light absorption in a wavelength region other than the wavelength of the visible light.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a light absorbing material, specifically, a material having light absorption in the green and blue wavelength regions is added to or mixed with a red light emitting phosphor layer. A material having light absorption in the red and blue wavelength regions is added to or mixed with the green light emitting phosphor layer. A material having light absorption in the red and green wavelength regions is added to or mixed with the blue light emitting phosphor layer.
With these configurations, it is possible to absorb light in other wavelength ranges except for the wavelength range of light emitted by the phosphor itself. As a result, in the case of a reflective display panel, the amount of reflected external light can be reduced, and in the case of a transmissive display panel, the amount of transmitted external light can be reduced.

The addition of the material that absorbs external light is not limited to the method of directly mixing the paste into the phosphor layer forming paste.
Prepare a paste to which a material that absorbs external light is added separately from the phosphor paste or the phosphor paste,
A phosphor layer may be formed.

The phosphor layer can have various structures by disposing a material absorbing external light at an appropriate position in the phosphor layer. When a material that absorbs external light is uniformly applied to the surface of the phosphor particles in the phosphor layer, when the material is uniformly mixed and arranged in the phosphor layer, a material that absorbs external light is further applied to an appropriate region. There is a case where they are added and arranged at a concentration. In particular, by arranging an appropriate thickness and concentration on the substrate side not directly irradiated with the vacuum ultraviolet ray, the contrast can be improved without affecting the luminance life of the phosphor layer.

Regardless of the position of the material that absorbs external light in the phosphor layer, to reduce the absorption of vacuum ultraviolet light, the particle size of the material that absorbs external light should be reduced by the vacuum ultraviolet light that is the excitation light. It is effective to make the wavelength equal to or smaller than the wavelength size. This makes it possible to reduce the absorption of vacuum ultraviolet light by the material that absorbs external light, and to maintain the excitation light intensity and emission luminance of the phosphor. In the present invention, as a median particle diameter of a material that absorbs external light, 500 nm to 300 nm larger than the wavelength size,
200nm to 150nm of equivalent size, 100nm to 70nm of 1/2 size, 30n of 1/4 size or less
Four types from m to 10 nm were prepared. Observing the relationship between the luminance and the external light reflectance, it was confirmed that a smaller central particle size was more effective. The median particle size is determined by measuring the frequency distribution of the phosphor particles (particle size) with a particle size distribution measuring device and indicating the median value of the total particle weight in the weight-based distribution.

Furthermore, the content of the material that absorbs external light with respect to the phosphor is an important parameter for balancing the amount of absorption of vacuum ultraviolet light and the amount of absorption of external light, and needs to be optimized. According to the present invention, the concentration of a material absorbing external light with respect to various phosphors is optimized, and the concentration is 5 wt% or less and the luminance is 60% or more (the luminance of the phosphor layer when the material absorbing external light is not included). Is set to 100%). In addition, the reflectance of light other than the wavelength region emitted by itself decreases with its concentration, and at 5 wt%, the reflectance is 40% or less in any combination of materials. In the present invention, the relationship between the luminance and the reflectance has been verified, and the content that can suppress the reduction of the emission luminance to a certain level and obtain an effective value of the reflectance has been found.

Further, according to the present invention, Fe ₂ O _{3 is} used as a material having light absorption in green and blue wavelength regions, ZnO / TiO ₂ / NiO / CoO is used as a material having light absorption in red and blue wavelength regions,
CoO / Al as a material having light absorption in the red and green wavelength regions
It has been found that using ₂ O ₃ is effective. These materials can effectively reduce the reflected light amount or transmitted light amount of external light by absorbing light in other wavelength regions except for the wavelength region of light emitted by the phosphor itself. The concentration in these phosphor layers, regardless of the phosphor species mixed,
It has been found that a content of 5 wt% or less has a sufficient reflectance reducing effect. However, in order to suppress the decrease in luminance as much as possible, it is necessary to further lower the concentration. The luminance is 70% at 2 wt%, the luminance is 80% at 1 wt%, and 0.2%.
It turned out that 90% of luminance can be maintained at 5 wt%.

When these phosphor layers are applied to a display device using vacuum ultraviolet rays as an excitation source, especially to a display panel of a plasma display, regardless of the combination of any kind of phosphor and a material absorbing external light. It is important to form the phosphor layer in consideration of the above addition method, particle size and concentration. In addition, when the phosphor layer of the present invention is applied to a display panel of a plasma display or the like, not only are all phosphor layers emitting red, green, and blue lights simultaneously applied, but also two kinds of appropriate phosphors are used. Even when applied to a combination of body layers, or applied to any one kind of phosphor layer, a contrast improvement effect by reducing the reflectance or the transmittance of external light can be obtained. In particular, it is important to improve the contrast as the definition of a display panel of a plasma display increases. Therefore, the contrast can be easily improved by applying the phosphor layer of the present invention to a display panel of a plasma display having various partition intervals. The fluorescent film for improving contrast of the present invention can be applied to various material combinations without being restricted by the combination of the phosphor species and the external light absorbing material shown in the embodiment, and a conventional neutral density filter can be provided on the front surface of the display panel glass. It can be used in combination with a provided contrast improvement method. Such a combination of the simple contrast improvement methods can be applied to a display panel of a plasma display capable of realizing a large screen. Further, by applying the phosphor layer of the present invention to a display panel of a high-definition plasma display in which a partition interval formed in the display panel is 200 μm or less, a reduction in luminance is minimized and contrast is improved. Can be.

Hereinafter, the present invention will be described in detail with reference to embodiments.

Embodiment 1 FIG. 1 shows a space between a pair of partition walls (200 μm) of one substrate of a display panel.
The following shape is shown in the sectional view. The phosphor layer of the present invention
As shown in FIG. 2, fine particles of an external light absorbing material are adhered and mixed on the surface of the phosphor particles or on the interparticle gaps with phosphor particles having a median particle diameter of 10 μm or less. The phosphor layer is formed after the address electrodes and the partition walls are formed on the back substrate. After mixing 40 parts by weight of the phosphor particles and 60 parts by weight of the vehicle to form a phosphor paste and applying by screen printing,
By the drying and baking steps, the volatile components in the paste are evaporated and the organic substances are removed by burning to form a phosphor layer.

In the present embodiment, the following materials are used as materials having light absorption in an arbitrary wavelength region. The material system actually used is an iron oxide-based material (Fe ₂ O ₃ ) with strong absorption in the blue and green regions in the red phosphor layer, and cobalt green with strong absorption in the blue and red regions in the green phosphor layer. Material (ZnO /
TiO ₂ / NiO / CoO) is a cobalt blue type (CoO / Al ₂ O ₃ ) having strong absorption in the green and red regions in the blue phosphor layer, and each median particle size is shorter than the excitation light of 200 nm. Of fine particles of 50 nm or less (10 to 30 nm), which are about 約 wavelength of the vacuum ultraviolet rays (147 nm and 172 nm). These fine particles of the external light absorbing material are weighed out at an appropriate weight ratio to the fluorescent particles, here 0.5 wt%, and then the fluorescent mixture containing the light absorbing material and the vehicle are mixed together by 4%.
The mixture was prepared at 0:60, mixed and stirred sufficiently to prepare a phosphor paste containing a light absorbing material, and a phosphor layer was prepared by the above procedure. The respective phosphor materials used in this example are as follows. The red phosphor is (Y, Gd) BO ₃ : Eu, the green phosphor is Zn ₂ SiO ₄ : Mn, and the blue phosphor is BaMgAl ₁₀ O ₁₄ : Eu
It is. A display of a plasma display in which a phosphor layer is formed on a rear substrate by the combination of such a phosphor composition and an external light absorbing material, and the front substrate and the rear substrate are adhered to each other in the same manner as in the related art and a discharge gas is sealed. A panel was prepared.

Embodiment 2 In this embodiment, the median particle size of each of the three types of external light absorbing materials used is set to about one-half wavelength of vacuum ultraviolet light (147 nm and 172 nm) having a wavelength shorter than 200 nm as excitation light. Become 10
A phosphor layer was formed by a conventional method and procedure in the same manner as in Example 1 except that fine particles of 0 nm or less (70 to 100 nm) were used, and a display panel of a plasma display was manufactured.

Embodiment 3 In this embodiment, the median particle diameter of each of the three types of external light absorbing materials used is set to the vacuum ultraviolet rays (147 nm and 17
200 nm or less (150 nm) which is equivalent to a wavelength size of 2 nm.
A phosphor layer was formed by a conventional method and procedure in the same manner as in Example 1 except that fine particles having a diameter of 200 nm to 200 nm were used, and a display panel of a plasma display was manufactured.

Embodiment 4 In this embodiment, the median particle size of each of the three types of external light absorbing materials used is a particle size larger than the wavelength size of vacuum ultraviolet rays (147 nm and 172 nm) of about 200 nm as excitation light. A phosphor layer was formed by a conventional method and procedure in the same manner as in Example 1 except that fine particles of 500 nm or less (300 to 500 nm) were used, and a display panel of a plasma display was manufactured.

COMPARATIVE EXAMPLE 1 Next, as a comparative example of Examples 1 to 4, a conventional phosphor paste was prepared in order to prepare a phosphor layer in which no external light absorbing material was mixed. To form a phosphor layer, and further, a display panel for a plasma display.

Here, the display panel of each example was evaluated based on the display panel characteristics of Comparative Example 1.

The brightness of each display panel was 92% for the display panel of the first embodiment and 92% for the display panel of the first comparative example.
88% of the display panels and 85 of the display panels of the third embodiment
%, And the display panel of Example 4 was 82%. Next, the reflectance of the phosphor layer in each example was evaluated. In order to avoid the influence of the partition walls and the like on the reflectance, a sample was prepared in which the phosphor layers of each color were separately applied on a glass substrate under the conditions in the above example.

The reflectance of these samples was measured, and the average reflectance was calculated. Average reflectance in Comparative Example 1 was 90%, Example 1
67% in Example 2, 70% in Example 2, 73% in Example 3, and 75% in Example 4. As described above, it was possible to obtain relatively good luminance and reflectivity characteristics at any particle diameter, and to achieve improvement in contrast while suppressing reduction in luminance. However, the wavelength of the vacuum ultraviolet ray, which is the excitation light, is 1 /
Better characteristics can be obtained by making the particle size as short as 2, 1/4.

From the above evaluation results of the display panel and the phosphor layer, it was found that the smaller the central particle size of the external light absorbing material is, the smaller the influence on vacuum ultraviolet rays is, and the desired effect can be easily obtained. This is presumably because vacuum ultraviolet absorption by a material absorbing external light can be reduced, and the amount of excitation light by the phosphor and the emission luminance can be maintained. Therefore, it is effective and desirable that the particle size of the material that absorbs external light be equal to or smaller than the wavelength size of the vacuum ultraviolet light that is the excitation light.

Embodiment 5 In this embodiment, a method of arranging an external light absorbing material at an appropriate thickness and concentration on a substrate side not directly irradiated with vacuum ultraviolet rays was examined. Each phosphor material used here is as follows. The red phosphor is (Y, Gd) (P, V) O4: Eu, the green phosphor is BaAl ₁₂ O ₁₉ : Mn, and the blue phosphor is BaMgAl
₁₀ O ₁₄ : Eu. In this embodiment, the median particle diameter of each of the three types of external light absorbing materials used is about 1/100 of the vacuum ultraviolet light (147 nm and 172 nm) having a wavelength shorter than 200 nm, which is the excitation light.
Using fine particles having a wavelength of 50 nm or less (10 to 30 nm), which are four wavelengths, two types of phosphor paste containing 1 wt% of the phosphor particles and a phosphor paste containing no external light absorbing material were prepared. Other conditions followed the procedure of Example 1.

To arrange the external light absorbing material on the rear substrate side, first, a phosphor layer of about 10 μm is formed on the rear substrate with a phosphor paste containing 1 wt% of the external light absorbing material on the rear substrate by a conventional method and after drying. Using an additive-free phosphor paste, an additive-free phosphor layer of 10 μm was further formed on the phosphor layer. FIG. 5 shows a cross-sectional structure of the phosphor layer. There is no external light absorbing material on the side irradiated with vacuum ultraviolet light. Next, the front substrate 1 and the rear substrate 2 were bonded to each other, and a discharge gas was filled therein, thereby producing a display panel of a plasma display.

COMPARATIVE EXAMPLE 2 Next, as a comparative example of the fifth embodiment, a conventional phosphor paste was prepared in order to prepare a phosphor layer in which no external light absorbing material was mixed. A body layer was prepared (similarly, divided into two parts), and a display panel of a plasma display was further prepared.

Next, the display panel of Example 5 was evaluated based on the display panel characteristics of Comparative Example 2. Regarding the luminance of the display panel, the display panel of Example 5 was 95% of the display panel of Comparative Example 2. Next, the reflectance at the phosphor layer was evaluated. The measurement of the reflectance was performed in the same manner as described above. The average reflectance in Comparative Example 2 is 90%, and the average reflectance in Example 5 is 70%, so that relatively good luminance and reflectance characteristics can be obtained, and a reduction in luminance is suppressed and an improvement in contrast is realized. We were able to. Also, the luminance life was substantially the same as that of Comparative Example 2.

From the above evaluation results of the display panel and the phosphor layer, the case where the layer containing the external light absorbing material is disposed on the back substrate side in the phosphor layer can be compared with the case where the external light absorbing material is disposed on average. Almost the same characteristics could be obtained. In particular, the contrast could be improved without affecting the luminance life of the phosphor layer. By this method, the phosphor layer containing the external light absorbing material can have various structures by appropriately selecting the arrangement position and the addition concentration.

Examples 6 to 11 and Comparative Example 3 Luminance and reflectance characteristics of the phosphor layer greatly change depending on the content of a material absorbing external light with respect to the phosphor. this is,
It is considered that the main reason is that the addition of the external light absorbing material absorbs the vacuum ultraviolet light, which is the excitation light, by the external light absorbing material and affects the luminance characteristics. Therefore, the characteristics of the luminance (a measure of the amount of absorption of the excitation light) and the reflectance (a measure of the amount of absorption of the external light) of the phosphor layer alone were evaluated using the content of the material absorbing the external light with respect to the phosphor as a parameter. The luminance characteristics were measured by using a deuterium lamp as a light source, extracting only vacuum ultraviolet light having a wavelength of 200 nm or less using a filter, and using the light as excitation light. The reflectance was measured with a spectrophotometer. In Examples 6 to 11 and Comparative Example 3, the concentration of an iron oxide-based material (Fe ₂ O ₃ ) added and mixed with the red phosphor layer and having strong absorption in the blue and green regions was optimized. The median particle size of the external light absorbing material is
Vacuum ultraviolet light having a wavelength shorter than 200 nm (147
nm and 172 nm), which is about 1/4 wavelength and 50 nm or less (10
From 30 nm). Here, the red phosphor (Y, G
d) BO ₃ : Eu was used. In this combination, the concentration is from 0 to 5
It was changed to wt%. Table 1 summarizes the relationship between density, relative luminance, and reflectance.

[0032]

[Table 1]

The reflectance is 600 nm (red), 530 nm
(Green) and 450 nm (blue) at each wavelength. From the evaluation results, the concentration at which the luminance of 70% can be maintained for Comparative Example 3 was 2 wt%, the concentration of maintaining the luminance of 80% for Comparative Example 3 was 1 wt%, and the concentration of maintaining the luminance of 90% for Comparative Example 3 was 0.5 wt%. It is. The reflectivity in the blue region at these densities is all 70% or less. In particular, at 5 wt%, the average reflectance is 20% or less. Even when other red phosphors, (Y, Gd) (P, V) O ₄ : Eu or Y ₂ O ₃ : Eu, are used, the concentration at which the relative luminance can be maintained at 80% is 1 wt%, and similar characteristics are obtained. I found it to have.

Examples 12 to 17 and Comparative Example 4 Next, a cobalt green material (ZnO / TiO ₂ / NiO / Co) having a strong absorption in the blue and red regions to be added to and mixed with the green phosphor layer was used.
O) was optimized for its concentration. The median particle diameter of the external light absorbing material is about ４ wavelength of vacuum ultraviolet light (147 nm and 172 nm) having a wavelength shorter than 200 nm which is excitation light.
nm or less (10 to 30 nm) was prepared. Here, Zn ₂ SiO ₄ : Mn was used for the green phosphor. Table 2 summarizes the results of varying the concentration from 0 to 5 wt% with this combination.

[0035]

[Table 2]

From the results, it was found that the luminance of Comparative Example 4 was 70%.
% Can be maintained at a concentration of 2 wt%, and the luminance of Comparative Example 4 is 80.
% Is 1 wt%, and the luminance is 9 compared to Comparative Example 3.
The concentration that can maintain 0% is 0.5 wt%. The reflectivity in the blue region at these densities is all 70% or less. In particular, at 5 wt%, the average reflectance is 40% or less. Further, even when another phosphor, BaAl ₁₂ O ₁₉ : Mn, was used, the concentration at which the relative luminance was maintained at 80% was 1 wt%.

Examples 18 to 23 and Comparative Example 5 Next, the concentration of cobalt blue type (CoO / Al ₂ O ₃ ) which is added to and mixed with the blue phosphor layer and has strong absorption in the green and red regions is optimized. Was done. The median particle size of the external light absorbing material is a vacuum ultraviolet ray (147 nm) having a wavelength shorter than the excitation light of 200 nm.
172 nm) and 50 nm or less (10 to 30 nm), which is about a quarter wavelength. Here, the blue phosphor is BaMgAl ₁₀
O ₁₄ : Eu was used. In this combination, the concentration is 0 to 5 wt.
Table 3 summarizes the results obtained by changing the values to%.

[0038]

[Table 3]

From the results, it was found that the luminance of Comparative Example 5 was 70%.
% Can be maintained at a concentration of 2 wt%, and the luminance of Comparative Example 4 is 80.
% Is 1 wt%, and the luminance is 9 compared to Comparative Example 3.
The concentration that can maintain 0% is 0.5 wt%. The reflectance in the red region at these densities is all 70% or less. In particular, at 5 wt%, the average reflectance is 50% or less. Further, even when another phosphor, Y (P, V) O _4, is used, the relative luminance is 8%.
The concentration maintaining 0% was 1 wt%.

Summarizing the evaluation results of Examples 6 to 23 and Comparative Examples 3 to 5, the luminance characteristics are almost the same regardless of which external light absorbing material is used, and it is necessary to maintain a relative luminance of 70%. To maintain a density of 2 wt% and a relative luminance of 80%, the density should be 1 wt%, and to maintain a relative luminance of 90%, the density should be
It is necessary to make it smaller than 0.5 wt%. It was also found that the reflectance could be reduced by increasing the density.
From this result, it was found that the relationship between the luminance and the mixed concentration thereof was very well matched irrespective of the type of the external light absorbing material and the type of the phosphor to be combined. This is very useful data for actually applying the phosphor layer containing the external light absorbing material to a display panel of a plasma display. It is considered that the reason why such similar characteristics were obtained is that the external light absorbing materials have similar absorption characteristics in the vacuum ultraviolet region. It is considered that this relationship between luminance and density can be applied to other external light absorbing materials.

Example 24 In the above examples, comparative evaluations were made of the case where the same concentration of each external light absorbing material was added to and mixed with the red, green and blue phosphor layers on the same substrate. Here, a case will be described in which each phosphor layer is formed by adding and mixing a different concentration of an external light absorbing material for each emission color on a rear substrate and applied to a display panel of a plasma display.

As a material system actually used, an iron oxide-based material (Fe ₂ O ₃ ) having strong absorption in the blue and green regions is used for the red phosphor layer, and blue and red are used for the green phosphor layer. Cobalt green material (ZnO / TiO ₂ / NiO / C) with strong absorption in the region
oO) is a cobalt blue type (CoO / Al ₂ O ₃ ) having a strong absorption in the green and red regions in the blue phosphor layer, and the center particle diameter of each of them is shorter than 200 nm which is excitation light.
Fine particles of 50 nm or less (10 to 30 nm), which are about 約 wavelength of 47 nm and 172 nm), were prepared. In each of the phosphor species used, the red phosphor is (Y, Gd) BO ₃ : Eu, the green phosphor is Zn ₂ SiO ₄ : Mn, and the blue phosphor is BaMgAl ₁₀ O ₁₄ :: Eu.
It is. The mixing concentration of the external light absorbing material applied in this embodiment is:
The red phosphor layer contains 0.1 wt%, the green phosphor layer has 0.5 wt%, and the blue phosphor layer has 0.5 wt%. The procedure of forming the phosphor layer and producing the display panel was performed according to Example 1 and the conventional steps. The size of the display panel used in this example is 25 inches, the number of pixels XG
The cell pitch is 165 μm x 495 μm at A (1024 × 768).

COMPARATIVE EXAMPLE 6 Next, as a comparative example of Example 24, a conventional phosphor paste was prepared in order to prepare a phosphor layer in which no external light absorbing material was mixed. Layers were formed (similarly, divided into two layers), and a display panel of a 25-inch XGA plasma display was formed.

Next, the display panel of Example 24 was evaluated with reference to the display panel characteristics of Comparative Example 6. As for the luminance of the display panel, the display panel of Example 24 was 90% of the display panel of Comparative Example 6. Next, the external light reflection of the display panel was compared. It was also confirmed that the reflectance of the display panel was lower than that of Comparative Example 6.

Example 25 Each of the phosphor species to be used next was determined such that the red phosphor was (Y, Gd) (P,
V) The case where O ₄ : Eu was used, the green phosphor was Zn ₂ SiO ₄ : Mn, and the blue phosphor was BaMgAl ₁₀ O ₁₄ : Eu was examined. The mixing concentration of the external light absorbing material applied in this embodiment is 0.2 wt% for the red phosphor layer, 1 wt% for the green phosphor layer, and 1 wt% for the blue phosphor layer. The procedure for forming the phosphor layer and preparing the display panel was performed in accordance with Example 24.

Comparative Example 7 Next, as a comparative example of Example 24, a paste using the same phosphor type as in Example 25 was prepared in order to prepare a phosphor layer in which no external light absorbing material was mixed. A phosphor layer was prepared in the same procedure as in Example 24 (similarly, divided into two steps).
Then, a display panel of a 25-inch XGA plasma display was manufactured.

Based on the display panel characteristics of Comparative Example 7, the display and display evaluation of Example 24 was performed. As for the panel luminance, the display panel of Example 25 had a relative luminance of 85% with respect to the display panel of Comparative Example 7. Further, it was confirmed that the reflectance of the display panel of Example 25 was lower than those of Comparative Example 7 and Example 24.

Embodiment 26 This embodiment describes the results of a study on a display panel of a plasma display in which an external light absorbing material is added and mixed only to the red and blue phosphor layers.

The actual structure of the phosphor layer is such that an iron oxide-based material (Fe ₂ O ₃ ) having strong absorption in the blue and green regions in the red phosphor layer
From each phosphor layer without adding any external light absorbing material to the green phosphor layer and adding a cobalt blue type (CoO / Al ₂ O ₃ ) with strong absorption in the green and red regions to the blue phosphor layer Become. The median particle diameter of each external light absorbing material is vacuum ultraviolet light (147 nm and 172 nm) having a wavelength shorter than 200 nm which is excitation light.
m) of 50 nm or less (10 to 30 n
m) microparticles were used. Also, each phosphor species used is
The red phosphor is (Y, Gd) BO ₃ : Eu, and the green phosphor is BaAl ₁₂ O
₁₉ : Mn, and the blue phosphor is BaMgAl ₁₀ O ₁₄ : Eu. The mixed concentration of the external light absorbing material applied in the present embodiment is different in the red phosphor layer.
The content is 0.2% by weight and 0.9% by weight in the blue phosphor layer. The procedure of forming the phosphor layer and producing the display panel was performed according to Example 1 and the conventional steps. Its size is 40 inches, equivalent to the number of pixels of VGA (640 × 480), and the cell pitch is 0.40 mm × 1.10 mm.

Comparative Example 8 Next, as a comparative example of Example 26, a display panel of a 40-inch VGA plasma display was manufactured without mixing any external light absorbing material in all the phosphor layers. Phosphor species were determined in Example 2.
6 and the same combination.

Next, the display panel of Example 26 was evaluated with reference to the display panel characteristics of Comparative Example 8. The display panel of Example 26 was 95% brighter than the display panel of Comparative Example 8. Next, the external light reflection of the display panel was compared. It was also confirmed that the reflectance of the display panel was lower than that of Comparative Example 8. Further, by comparing the contrast characteristics, it was confirmed that the display panel in which the external light absorbing material was added only to the two kinds of phosphor layers could improve the contrast as compared with the conventional display panel.

Example 27 In this example, a display panel of a 25-inch XGA plasma display in which an external light absorbing material was added and mixed only to the red phosphor layer was examined.

Actually, an iron oxide-based material (Fe ₂ O ₃ ) having strong absorption in the blue and green regions is added to the red phosphor layer, and an external light absorbing material is added to the green phosphor layer and the blue phosphor layer. Each phosphor layer was formed without doing so. In each of the phosphor species used, the red phosphor was (Y, Gd) (P, V) O ₄ : Eu, and the green phosphor was BaAl ₁₂ O ₁₉ :
Mn, and the blue phosphor is BaMgAl ₁₀ O ₁₄ : Eu. The mixture concentration of the external light absorbing material of the red phosphor layer applied in the present embodiment is 2 wt%.
It is. The procedure of forming the phosphor layer and preparing the display panel is as follows.
It carried out according to Example 1 and the conventional process.

Comparative Example 9 Next, as a comparative example of Example 27, a 25-type XGA plasma display having the same combination of phosphor species as in Example 27 and no external light absorbing material mixed in all the phosphor layers was used. A display panel was manufactured.

The display panel of Example 27 was evaluated based on the display panel characteristics of Comparative Example 9. The luminance of the display panel of the display panel of Example 27 was 90% of that of the display panel of Comparative Example 9. Further, in the display panel characteristics, it was confirmed that the reflectance was lower than that of Comparative Example 9 and the contrast was improved.

As a result, it was confirmed that the contrast of the display panel of the 25-inch XGA plasma display can be improved as compared with the conventional display panel by adding an external light absorbing material to some of the phosphor layers.

Examples 24 to 27 and Comparative Example 6
The results of 9 to 9 can be summarized as follows. By independently selecting the additive concentration of the external light absorbing material to be mixed with the red, green, and blue phosphor layers, the reflectivity can be maintained while maintaining the display panel luminance at a substantially constant level. Can be easily changed. In addition, it was confirmed that even if the external light absorbing material was not necessarily added to all the phosphor layers, the effect of sufficiently reducing the reflectance was sufficient. In the display panel of the 25-inch XGA plasma display studied here, the contrast was improved compared to the conventional display panel. The improvement is more remarkable than in the case of the 40-inch display panel, and it can be seen that the present invention is more effective when applied to a high definition display panel.

In the above examples, the relationship between the luminance and the reflectance was demonstrated, and the reduction in the emission luminance was suppressed to a certain level, and the phosphor layer containing the external light absorbing material was able to obtain an effective value of the reflectance. The structure and the concentration of the external light absorbing material were found, and an application test was performed on a display panel of an actual plasma display.
The fluorescent film for improving contrast of the present invention can be applied to various material combinations without being restricted by the combination of the phosphor species and the external light absorbing material shown in the embodiment, and a conventional neutral density filter can be provided on the front surface of the display panel glass. The present invention can be used in combination with a contrast improving method to be provided, and can be applied to a display device using vacuum ultraviolet light as an excitation source, particularly a plasma display.

This plasma display has an AC type,
There is a DC type, and these display panels are incorporated together with their drive circuits and the like. These display panels include a reflection type and a transmission type.

[0060]

According to the present invention, a highly practical and high-contrast plasma display can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a cell of a display panel of a plasma display according to one embodiment of the present invention, in which a distance between partitions is 200 μm or less.

FIG. 2 is a cross-sectional view showing an example of a phosphor layer to which external light absorbing material fine particles according to the present invention are added and mixed.

FIG. 3 is a schematic view of a display panel of a conventional AC plasma display.

FIG. 4 is a schematic view of a display panel of a conventional AC plasma display.

FIG. 5 is a cross-sectional view of a cell showing a phosphor layer structure of a display panel of a plasma display according to the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01J 11/02 H01J 11/02 Z 17/04 17/04

Claims (14)

[Claims] 1. A phosphor layer comprising phosphor particles that emit visible light upon excitation of ultraviolet light having a wavelength of 200 nm or less, and a material having light absorption in a wavelength region other than the wavelength of the visible light. 2. The phosphor layer according to claim 1, wherein the phosphor layer is a mixture of the phosphor particles and the material having light absorption. 3. The phosphor layer according to claim 1, wherein the phosphor layer is a laminate partially including a layer made of a mixture of the phosphor particles and the material having light absorption. . 4. The phosphor according to claim 2, wherein the content of the material having light absorption in the mixture is 5 wt% or less with respect to the phosphor particles in the mixture. layer. 5. The phosphor layer according to claim 4, wherein said content is less than 1 wt%. 6. The method according to claim 1, wherein
The phosphor layer, wherein the material having light absorption has a median particle diameter of 200 nm or less. 7. The phosphor layer according to claim 6, wherein the material having light absorption has a median particle size of 100 nm or less. 8. The phosphor layer according to claim 7, wherein the material having light absorption has a median particle size of 50 nm or less. 9. The method according to claim 1, wherein
The phosphor layer, wherein the material having light absorption is a system containing Fe ₂ O ₃ and has light absorption in blue and green wavelength regions. 10. The material according to claim 1, wherein the material having light absorption is a system containing ZnO / TiO ₂ / NiO / CoO, and has light absorption in red and blue wavelength regions. A phosphor layer characterized by the following. 11. The material according to claim 1, wherein the material having light absorption is a system containing CoO / Al ₂ O ₃ and has light absorption in red and green wavelength regions. Phosphor layer. 12. A phosphor layer according to claim 1, further comprising: an excitation source for generating an ultraviolet ray having a wavelength of 200 nm or less for exciting the phosphor layer. Display device. 13. A display panel comprising: a display panel; and a driving circuit for driving the display panel, wherein the display panel is formed of a phosphor layer according to claim 1. A body layer, a pair of electrodes, and a gas that generates ultraviolet light having a wavelength of 200 nm or less when a discharge is generated by a voltage applied to the pair of electrodes from the drive circuit, and the ultraviolet light includes the red, blue, and green phosphors. A display device which emits visible light by exciting a layer. 14. The display device according to claim 13, wherein the display panel has a partition for defining the discharge area, and the interval between the partitions is 200 μm or less.