JP2006265432A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the chromaticity of a phosphor film for a field emission type display device and enhance the lifetime of luminance. <P>SOLUTION: A field emission type display device provided with a face plate having a phosphor film formed thereon and an electron source for irradiating an electron beam on the phosphor film is provided, which uses a phosphor film formed by mixing or laminating a phosphor composed of ZnS as a base material and having a shoulder of the emission observed on the 0.3 eV high-energy side of the primary emission of the emission spectrum and a phosphor composed of Y<SB>2</SB>SiO<SB>5</SB>as a base material. The use of the phosphor film improves chromaticity characteristics which have not been solved by the conventional method and leads to the improvement of the lifetime of luminance. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to an image display device including a face plate on which a fluorescent film is formed and an electron source that irradiates the fluorescent film with an electron beam, and in particular, ZnS phosphor and Y ₂ as phosphors constituting the fluorescent film. mixing a SiO ₅ phosphor, or a field emission display device, characterized in that a laminate of these phosphors (hereinafter referred to as FED).

  In video information systems, various display devices are actively researched and developed in response to various demands such as high definition, large screen, thinning, and low power consumption. In recent years, research and development of FED has been actively conducted as a display that realizes thinning and low power consumption to meet such demands.

  The FED has a structure in which a planar field emission electron source is installed on the back of the vacuum envelope, and a fluorescent film is installed on the inner surface of the front face plate. The acceleration voltage is about 0.1 to 10 kV. The fluorescent film is irradiated with an electron beam to emit light, and an image is displayed.

  Here, since the current density of the electron beam applied to the fluorescent film is about 10 to 1000 times that of a general cathode ray tube, it is a high current density. Therefore, the FED fluorescent film has a low resistance characteristic that does not cause charge-up. desired. Furthermore, a life characteristic under a high current density is good, and a characteristic with low luminance saturation and high luminance is also required.

  Until now, various developments have been made in order to realize low resistance, long life and high brightness of the fluorescent film. As a method for improving the performance of the FED phosphor film by mixing phosphors, for example, as shown in Patent Document 1, a high-resistance phosphor and a low-resistance phosphor are mixed and excellent at a driving voltage of 2 kV or less. There are methods having luminance characteristics.

  Further, for example, as disclosed in Patent Document 2, it is composed of a mixed phosphor of a sulfide-based phosphor and an oxide-based phosphor that is an aluminate-based or silicate-based phosphor of yttrium. There is a good way. However, there is no description about a method using a ZnS phosphor in which a light emission shoulder is observed on the high energy side of the main light emission of the emission spectrum.

  Until now, various methods have been studied in order to realize low resistance, long life, and high brightness of FED phosphor films. However, these conventional methods have not solved all the problems. In particular, there is a need for a new method that has good chromaticity and realizes a long life.

Japanese Patent Laid-Open No. 09-87618 JP-A-12-96046

  Accordingly, an object of the present invention is to improve the luminance life and chromaticity characteristics of the above-described conventional fluorescent film, and to provide an image display device having excellent luminance life characteristics.

The above object is a field emission display device comprising a face plate on which a fluorescent film is formed and an electron source for irradiating the fluorescent film with an electron beam, wherein the phosphor forming the fluorescent film is based on ZnS. It is characterized in that it includes a mixture of a phosphor that is a material and has a phosphor emission shoulder observed on the high energy side of the main emission of the emission spectrum of 0.3 eV, and a phosphor that uses Y ₂ SiO ₅ as a base material. Achieved by the image display device.

  Here, as the composition of the phosphor using ZnS as a base material used for the phosphor film, the general formula ZnS: M, N (where M is any one of Cu, Ag, Au or a mixture of these, N is represented by any one of Al, Ga, In, and Cl, or a mixture of these.

In addition, the composition of the phosphor using Y ₂ SiO ₅ as a base material is represented by the general formula Y ₂ SiO ₅ : R (where R is one of Ce, Eu, Tb, Tm, or a mixture of these). It is preferable to use the phosphor described.

For example, the Y ₂ SiO ₅ : Ce phosphor has a good luminance maintenance ratio, but as a blue phosphor, the chromaticity is closer to bluish white than blue, and the emission luminance is also low. Therefore, by mixing with a ZnS: Ag, Al phosphor having a high-energy light-emitting component, a phosphor film close to the intended blue chromaticity can be obtained, and the emission luminance is improved. Further, the luminance maintenance ratio can be improved by mixing the Y ₂ SiO ₅ : Ce phosphor rather than using the ZnS: Ag, Al phosphor alone.

  In addition, a phosphor made into a mixed crystal by adding at least one element selected from the group consisting of the group IIa into the base crystal of ZnS, for example, using ZnS: Cu, Al phosphor by ZnMgS: Cu, Al phosphor Also, the emission luminance can be improved.

Further, a phosphor made into a mixed crystal by adding at least one element selected from the group consisting of the group IIIa into the base crystal of Y ₂ SiO ₅ , for example, a Y ₂ by a (Y, Gd) ₂ SiO ₅ : Ce phosphor. Luminance of light emission can be improved as compared with the use of SiO ₅ : Ce phosphor.

  The light emission luminance can be improved by using any one of these mixed crystal phosphors or a phosphor obtained by mixing them. Further, in the process of manufacturing these phosphors, for example, when baked using a flux, at least one trace impurity selected from the group consisting of Group Ia, Group VIIb, and rare earth may be contained.

The ZnS base crystal is generally a cubic phosphor. A hexagonal crystal or a mixed crystal of cubic and hexagonal crystals can be obtained by setting the firing temperature to 1020 ° C. or higher, or using Mg mixed crystal. In the case of the hexagonal crystal, the band gap is about 0.1 eV larger than that of the cubic crystal, so that the emission shifts to the short wavelength side. For example, in the case of a ZnS: Ag, Al phosphor, the emission color shifts from blue to blue-violet, which is suitable in terms of chromaticity for mixing with a blue-white Y ₂ SiO ₅ : Ce phosphor. The mixing ratio of the Y ₂ SiO ₅ phosphor to the ZnS phosphor is preferably in the range of 10 wt% or more and 50 wt% or less in terms of light emission luminance and chromaticity.

  In addition, the ZnS phosphor used here has improved lifetime characteristics by annealing in a sulfur-containing atmosphere at a processing temperature in the range of 100 ° C to 600 ° C. A light emission shoulder is observed. When the emission intensity at the shoulder portion of the emission spectrum is 4 times or more larger than the intensity fitted with a Gaussian curve when the horizontal axis is expressed in energy, the effect of annealing performed as the surface treatment of the ZnS phosphor is great. This high-energy light-emitting component is a light-emitting component known as Blue-Cu, which is observed at a high current density and 0.3 eV high-energy side of main light emission for ZnS: Cu, Al phosphors. The body is characterized by high component strength.

  Furthermore, with respect to ZnS phosphors added with Ag as the emission center, such as ZnS: Ag, Al phosphors, a Violet-Ag component that has not been conventionally known can be observed on the high-energy side of the main emission at 0.3 eV. The intensity of these high-energy luminescent components such as Blue-Cu and Violet-Ag is highly dependent on the sample temperature, and can be observed more clearly at a temperature as low as the liquid nitrogen temperature.

In addition, the surface of the phosphor particles used in the phosphor film of the present invention is covered with a translucent conductive film containing a translucent conductive material, thereby reducing the resistance. Examples of the light-transmitting conductive material include In ₂ O ₃ , MgO, and Sn ₂ O.

Regarding the structure of the phosphor film, in addition to a single-layer phosphor film composed of a mixture of ZnS phosphor and Y ₂ SiO ₅ phosphor, a layer composed of ZnS phosphor and a layer composed of Y ₂ SiO ₅ phosphor are laminated. It is also possible to have a multilayer structure.

Since the field emission display device of the present invention uses a phosphor film in which ZnS phosphor and Y ₂ SiO ₅ phosphor, in which a light emission shoulder is observed on the high-emission side of the main light emission of 0.3 eV, are used, a display is used. The chromaticity is good, and the luminance life is improved.

  Here, the manufacturing method of the phosphor used in the image display device of the present invention and the respective characteristics such as the luminance maintenance ratio will be described in detail, but the examples shown below show an example embodying the present invention, This invention is not restrained.

(1) Production of cubic ZnS: Ag, Al sulfurating treatment phosphor:
The cubic ZnS: Ag, Al sulfurating treatment phosphor used in the present invention can be produced by the method described below. Ag used as an activator was prepared by dissolving AgNO ₃ in pure water and adding a predetermined amount as a 10 ⁻⁴ mol / ml solution. Al used as coactivator was prepared by dissolving Al (NO ₃ ) ₃ · 9H ₂ O in pure water and adding a predetermined amount as a 10 ⁻⁴ mol / ml solution.

The amount of each raw material when ZnS: Ag, Al phosphor (Ag = 500 wt ppm, Al = 200 wt ppm) is as follows.
Zinc sulfide raw powder ZnS 9.746g
Silver solution Ag 0.451ml
Aluminum solution Al 0.722ml
The above raw materials are mixed well and dried. Next, the obtained phosphor raw material mixture is packed in a quartz boat, set in a quartz tube of a tubular synthesis furnace, and fired. Firing was performed in a hydrogen sulfide atmosphere by substituting the whole with Ar gas and then flowing H ₂ S gas at 100 ml / min into the quartz tube. The firing temperature was 950 ° C., and the firing time was 2 hours. The fired product was lightly loosened and then sieved to obtain a phosphor core used in the present invention.

Next, sulfur defects on the phosphor core surface are repaired by sulfuration treatment to reduce the sulfur defect concentration. The synthesized ZnS: Ag, Al phosphor is packed in a quartz boat and set in a quartz tube of a tubular synthesis furnace. After the entire gas was replaced with Ar gas, H ₂ S gas (200 ml / min) was allowed to flow through the quartz tube to perform sulfuration treatment in a hydrogen sulfide atmosphere. The annealing temperature was 400 ° C. and the annealing time was 0.5 hours. The ZnS: Ag, Al phosphor subjected to sulfurization was loosened and then sieved to obtain a phosphor used in the present invention.
(2) Measurement of emission spectrum of cubic ZnS: Ag, Al sulfurating treatment phosphor:
Next, the emission spectrum of the produced cubic ZnS: Ag, Al sulfurating treatment phosphor was measured. As a sample, a fluorescent film was formed on a Ni-plated Cu substrate by precipitation coating. The coating weight was 2-5 mg / cm ² . The prepared sample was set in a demountable device equipped with an electron gun and measured.

The electron beam in the demountable device is scanned left and right and up and down at the same frequency as a general television by a deflection yoke, and a square raster (electron beam irradiation range) is drawn in a certain range on the phosphor film produced as described above. The emission spectrum was measured under the conditions of an acceleration voltage of 7 kV, an irradiation area of 6 × 6 mm, an irradiation current of 20 μA, a current density of 56 μA / cm ² , and a sample temperature of −190 ° C. An optical fiber was installed on the electron beam irradiation side (reflection side) to capture light emitted by electron beam irradiation, and an emission spectrum was obtained through a spectrometer.

FIG. 1 shows an emission spectrum of a cubic ZnS: Ag, Al sulfurating treatment phosphor and a fitting result by a gauss curve thereof. The emission spectrum of the cubic ZnS: Ag, Al sulfurating treatment phosphor is fitted by a gauss curve, and a shoulder is observed on the 0.3eV high energy side of the main emission of 2.8 eV in the sulfurating treatment phosphor. The emission intensity at 3.1 eV of the cubic ZnS: Ag, Al sulfurating treatment phosphor is 4.8 times as large as that of the gauss curve, and is more than 4 times larger. ZnS phosphors are characterized by increasing the emission intensity of the shoulder observed on the high-energy side of the main emission by 0.3 eV by performing sulfuration treatment.
(3) Evaluation of luminance characteristics of mixed phosphor film of cubic ZnS: Ag, Al sulfurating phosphor and Y ₂ SiO ₅ : Ce phosphor:
Next, luminance characteristics of the mixed phosphor film of cubic ZnS: Ag, Al sulfurating treatment phosphor and Y ₂ SiO ₅ : Ce phosphor were evaluated. A commercially available Y ₂ SiO ₅ : Ce phosphor was used. The phosphor film sample is a sample in which each phosphor is weighed and mixed so that the Y ₂ SiO ₅ : Ce phosphor becomes 0, 10, 30, 50% by weight with respect to the cubic ZnS: Ag, Al sulfurating treatment phosphor. A phosphor film was formed on a Cu substrate plated with Ni by precipitation coating. The coating weight was 2-5 mg / cm ² .

The prepared sample was set in a demountable device equipped with an electron gun and evaluated. Luminance and luminous intensity (radiation energy) through the radiometric filter were measured from the reflection side using a color difference meter and Si photocell. The luminance characteristics were evaluated under the conditions of an acceleration voltage of 7 kV, an irradiation area of 6 × 6 mm, an irradiation current of ² μA, a current density of 5.6 μA / cm ² , and a sample temperature of 20 ° C. Table 1 shows the evaluation results of the luminance characteristics.

表１から、Y₂SiO₅:Ce蛍光体の発光輝度は立方晶ZnS:Ag,Al硫化処理蛍光体の75.4%であるが、これは色度y値が0.198と大きいため見かけの輝度が高くでている。発光エネルギーは31.1%であり、青色蛍光体として用いる場合にはこちらの値を用いる方が妥当である。混合蛍光膜の色度y値を見ると、混合比率（括弧内に表示した）が50重量%まではy値の上昇が0.085と青色蛍光膜として使用可能な範囲である。

From Table 1, the emission brightness of the Y ₂ SiO ₅ : Ce phosphor is 75.4% of the cubic ZnS: Ag, Al sulfurating treatment phosphor, but this has a high apparent brightness because the chromaticity y value is as large as 0.198. It is out. The emission energy is 31.1%, and this value is more appropriate when used as a blue phosphor. Looking at the chromaticity y value of the mixed phosphor film, the increase in the y value is 0.085, up to 50% by weight of the mixing ratio (indicated in parentheses), which is a usable range as a blue phosphor film.

FIG. 2 shows an irradiation current amount change of the chromaticity y value. Chromaticity y value of cubic ZnS: Ag, Al sulfurating treatment phosphor tends to decrease as the amount of irradiation current increases, but as the mixing ratio of Y ₂ SiO ₅ : Ce phosphor increases, the chromaticity y value The change in y value is small. This is because the chromaticity change of the Y ₂ SiO ₅ : Ce phosphor is smaller than that of the cubic ZnS: Ag, Al sulfurating treatment phosphor.

FIG. 3 shows a change in the amount of irradiation current of the relative light emission luminance, and FIG. 4 shows a change in the amount of irradiation current of the relative light emission energy. The relative emission luminance of the mixed phosphor film tends to increase as the amount of irradiation current increases. This is a γ-characteristic of Y ₂ SiO ₅ : Ce phosphor (emission luminance increases with current, and the slope of luminance-current log-log plot is γ value) is cubic ZnS: Ag, Al sulfide treatment For example, the cubic ZnS: Ag, Al sulfurating treatment phosphor is better than the phosphor, and when the irradiation current amount is increased, the chromaticity y value is lowered and the luminance is lowered.

As seen in FIG. 4, in the mixed fluorescent film, the relative light emission energy tends to increase slightly as the irradiation current amount increases.
(4) Luminance maintenance ratio characteristic evaluation of mixed phosphor film of cubic ZnS: Ag, Al sulfurating treatment phosphor and Y ₂ SiO ₅ : Ce phosphor:
Next, the luminance maintenance factor characteristics of the mixed phosphor film of cubic ZnS: Ag, Al sulfurating treatment phosphor and Y ₂ SiO ₅ : Ce phosphor were evaluated. The sample preparation and evaluation apparatus is the same as in the luminance characteristic evaluation. The luminance maintenance rate acceleration test was performed under the conditions of an acceleration voltage of 7 kV, an irradiation area of 6 × 6 mm, an irradiation current of 100 μA, a current density of 278 μA / cm ² , a sample temperature of 200 ° C., and an electron beam irradiation time of 1 hour. Table 2 shows the evaluation results of the luminance maintenance rate and chromaticity change.

表１と表２で色度ｙ値が異なるのは、試料温度が異なるためである。表２に見られるようにY₂SiO₅:Ce蛍光体の発光エネルギーは評価前後で変化がなく、輝度維持率は良好である。ただし、色度ｙ値は電子線照射によって上昇する傾向が見られた。混合蛍光膜の輝度維持率は立方晶ZnS:Ag,Al硫化処理蛍光膜よりも高く、Y₂SiO₅:Ceの混合比率が10重量％と低い場合にも4.2％高い。また、評価前後における色度ｙ値の変化が小さい。

The reason why the chromaticity y value is different between Table 1 and Table 2 is that the sample temperature is different. As seen in Table 2, the emission energy of the Y ₂ SiO ₅ : Ce phosphor does not change before and after the evaluation, and the luminance maintenance rate is good. However, the chromaticity y value tended to increase due to electron beam irradiation. The luminance maintenance ratio of the mixed phosphor film is higher than that of the cubic ZnS: Ag, Al sulfurating treatment phosphor film, and is 4.2% higher even when the mixing ratio of Y ₂ SiO ₅ : Ce is as low as 10% by weight. Moreover, the change of the chromaticity y value before and after evaluation is small.

FIG. 5 shows luminance maintenance factor curves at the time of an accelerated test evaluation of a cubic ZnS: Ag, Al sulfide treatment phosphor film (thin line) and a mixed phosphor film (thick line) with a mixing ratio of 50 wt% of Y ₂ SiO ₅ : Ce. The brightness maintenance factor in Table 2 is different from the value in Table 2 when the emission energy at 2 μA of irradiation current is compared before and after the acceleration test, whereas in FIG. 5, the amount of irradiation current is as high as 100 μA. It is. As shown in FIG. 5, the emission energy of the mixed phosphor film is not significantly different from that of cubic ZnS: Ag, Al sulfide treatment phosphor film, but the initial degradation is kept low and the brightness is maintained. The rate is good.

  The hexagonal ZnS: Ag, Al sulfurating treatment phosphor used in the present invention can be produced in the same manner as in Example 1 except that the firing temperature of the phosphor is 1050 ° C. Table 3 shows the evaluation results of the light emission luminance characteristics.

混合蛍光膜の色度ｙ値は混合比率が50重量％で0.082であり、青色蛍光膜として使用可能な範囲である。また、混合比率が30重量％では色度ｙ値が0.062と青色発光として良好である。

The chromaticity y value of the mixed phosphor film is 0.082 at a mixing ratio of 50% by weight, and is in a range that can be used as a blue phosphor film. Further, when the mixing ratio is 30% by weight, the chromaticity y value is 0.062, which is good as blue light emission.

FIG. 6 shows the irradiation current amount change of the chromaticity y value. The chromaticity y value of hexagonal ZnS: Ag, Al sulfurating treatment phosphor tends to decrease as the amount of irradiation current increases, but as the mixing ratio of Y ₂ SiO ₅ : Ce phosphor increases, the chromaticity y value The change in y value is small.

FIG. 7 shows changes in the amount of irradiation current of the relative light emission luminance, and FIG. 8 shows changes in the amount of irradiation current of the relative light emission energy. The relative luminance of the mixed phosphor film is higher than that of the hexagonal ZnS: Ag, Al sulfurating phosphor. The Y ₂ SiO ₅ : Ce phosphor has a higher luminance than the Y ₂ SiO ₅ : Ce phosphor. The characteristics are better than the hexagonal ZnS: Ag, Al sulfurating treatment phosphor. In the hexagonal ZnS: Ag, Al sulfurating treatment phosphor, the chromaticity y value decreases and the luminance decreases as the irradiation current increases. Can be mentioned.

As seen in Table 3, the relative emission energy cubic ZnS: substantially in the same manner as if a mixture of Ce _{phosphor, Y 2 SiO 5:: Ag} , Al sulfide treatment phosphor and Y ₂ SiO ₅ Ce phosphor Increasing the mixing ratio decreases.

  Further, as shown in FIG. 8, when the amount of irradiation current is increased, the relative emission energy of the mixed phosphor film tends to increase as compared with the hexagonal ZnS: Ag, Al sulfuration treatment phosphor film.

Next, the luminance maintenance factor characteristics of the mixed phosphor film of hexagonal ZnS: Ag, Al sulfurating treatment phosphor and Y ₂ SiO ₅ : Ce phosphor were evaluated. Table 4 shows the evaluation results of the luminance maintenance rate and chromaticity change.

表３と表４で色度ｙ値が異なるのは、試料温度が異なるためである。混合蛍光膜の輝度維持率は六方晶ZnS:Ag,Al硫化処理蛍光膜に比べて高くなっており、混合比率が10重量％の場合には輝度維持率は3.3％高くなっている。また、混合比率が低い場合には電子線照射による色度ｙ値の変化が小さい。

The reason why the chromaticity y value is different between Table 3 and Table 4 is that the sample temperature is different. The luminance maintenance ratio of the mixed phosphor film is higher than that of the hexagonal ZnS: Ag, Al sulfurating treatment phosphor film. When the mixing ratio is 10% by weight, the luminance maintenance ratio is 3.3% higher. When the mixing ratio is low, the change in chromaticity y value due to electron beam irradiation is small.

Figure 9 shows the luminance maintenance factor curve during the accelerated test of the mixed phosphor film (thick line) when the mixing ratio of the hexagonal ZnS: Ag, Al sulfide treatment phosphor film (thin line) and the Y ₂ SiO ₅ : Ce phosphor is 10 wt%. Indicates. As can be seen in FIG. 9, the emission energy of the mixed phosphor film is not significantly different from the luminance retention curve of the hexagonal ZnS: Ag, Al sulfide treatment phosphor film, but the initial degradation is kept low. The luminance maintenance rate is good.

As the mixed phosphor film of the present invention, a cubic ZnS: Ag, Cl sulfurating treatment phosphor and a (Y, Gd) ₂ SiO ₅ : Ce phosphor were mixed to produce a phosphor film, and the luminance and luminance maintenance ratio were evaluated. . The chromaticity and luminance maintenance rate of the mixed phosphor film were good as in Example 1.

A cubic ZnS: Cu, Al sulfurating treatment phosphor and a Y ₂ SiO ₅ : Tb phosphor were mixed as a mixed phosphor film of the present invention to produce a phosphor film, and the luminance and luminance maintenance rate were evaluated. The chromaticity of the mixed phosphor film was good for green light emission, and the luminance maintenance rate was good as in Example 1.

  As the mixed fluorescent film of the present invention, a cubic ZnS: Cu, Au, Al sulfurating treatment phosphor and a Y2SiO5: Tb phosphor were mixed to produce a fluorescent film, and the luminance and luminance maintenance ratio were evaluated. The chromaticity of the mixed phosphor film was good for green light emission, and the luminance maintenance rate was good as in Example 1.

ZnMgS: Cu, Al sulfurated phosphor (mixed crystal of cubic and hexagonal crystals) and (Y, Gd) ₂ SiO ₅ : Tb phosphor are mixed to produce a phosphor film as a mixed phosphor film of the present invention, and brightness・ Brightness maintenance rate was evaluated. The chromaticity of the mixed phosphor film was good for green light emission, and the luminance maintenance rate was good as in Example 1.

MIM type electron source display device (1):
The MIM type electron source display device of the present invention is shown in FIG. The MIM type electron source display device 12 includes a face plate 2, an MIM electron source 11, and a rear plate 7. The MIM type electron source 11 includes a lower electrode (Al) 8, an insulating layer (Al ₂ O ₃ ) 9, and an upper electrode. (Ir—Pt—Au) 10 is used. In particular, a blue phosphor film is formed inside the face plate 2 by mixing cubic ZnS: Ag, Al sulfurating phosphor (70 wt%) and Y ₂ SiO ₅ : Ce phosphor (30 wt%). There is a fluorescent film 3.

The average particle size of the phosphors was 6 μm. A Y ₂ O ₃ : Eu phosphor was used for the red phosphor film, and a Y ₂ SiO ₅ : Tb phosphor was used for the green phosphor film. In order to increase the definition, a black conductive material (black matrix) 1 was provided between the pixels.

  In the production of the black conductive material 1, a photoresist film is applied on the entire surface, exposed through a mask and developed to leave a photoresist film partially. Thereafter, after forming a graphite film on the entire surface, hydrogen peroxide or the like was applied to remove the photoresist film and the graphite thereon, thereby forming a black conductive material.

  A screen printing method was used for applying the fluorescent film. The phosphor is kneaded with a vehicle mainly composed of a cellulose-based resin to form a paste and is prepared. Next, a stamp is applied through a stainless mesh. The red, green, and blue phosphors were separately applied by matching the positions of the mesh holes with the positions of the respective phosphor films. Next, the phosphor film formed by printing was baked and mixed to remove the cellulose resin and the like. In this way, a phosphor pattern was formed. The average thickness of the fluorescent film was 15 μm. A metal back (not shown) is formed by film-depositing the inner surface of the fluorescent film 3 and vacuum-depositing Al in accordance with a known forming method. Then, it heat-processed and produced by skipping the filming agent. In this way, the phosphor film 3 is completed. The brightness maintenance rate of the MIM type electron source display was improved and showed a good brightness even after image display for a long time.

MIM type electron source display device (2):
The MIM type electron source display device of the present invention is shown in FIG. In particular, inside the face plate 2, as a blue fluorescent film, a fluorescent material in which hexagonal ZnS: Ag, Al phosphor (50 wt%) and (Y, Gd) ₂ SiO ₅ : Ce phosphor (50 wt%) are mixed. There is a membrane 3. A Y ₂ O ₃ : Eu phosphor was used for the red phosphor film, and a Y ₂ SiO ₅ : Tb phosphor was used for the green phosphor. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 7. The luminance life according to the present invention was as good as in (Example 7).

MIM type electron source display device (part 3):
The MIM type electron source display device of the present invention is shown in FIG. In particular, inside the face plate 2, there is a fluorescent film 3 in which a cubic ZnS: Ag, Cl phosphor (90% by weight) and a Y ₂ SiO ₅ : Ce phosphor (10% by weight) are mixed as a blue fluorescent film. . Y ₂ O ₂ S: Eu phosphor is used for the red phosphor film, and ZnMgS: Cu, Al (80 wt%) and Y ₂ SiO ₅ : Tb phosphor (20 wt%) are mixed for the green phosphor. A membrane was used. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 7. The luminance life according to the present invention was as good as in (Example 7).

MIM type electron source display device (part 4):
The MIM type electron source display device of the present invention is shown in FIG. In particular, as a blue fluorescent film on the inside of the face plate 2, cubic and hexagonal mixed crystal ZnMgS: Ag, Al sulfurated phosphor (70 wt%) and (Y, Gd) ₂ SiO ₅ : Ce phosphor ( There is a phosphor film 3 mixed with 30 wt%). Y ₂ O ₃ : Eu phosphor is used for the red phosphor film, and ZnS: Cu, Au, Al phosphor (50 wt%) and Y ₂ SiO ₅ : Tb phosphor (50 wt%) are used for the green phosphor. A mixed phosphor film was used. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 7. The luminance life according to the present invention was as good as in (Example 7).

MIM type electron source display device (part 5):
The MIM type electron source display device of the present invention is shown in FIG. In particular, inside the face plate 2, as a blue fluorescent film, a fluorescent mixture of cubic ZnS: Ag, Al, Cl sulfurating treatment phosphor (90% by weight) and Y ₂ SiO ₅ : Ce phosphor (10% by weight) is mixed. There is a membrane 3. A Y ₂ O ₂ S: Eu phosphor was used for the red phosphor film, and a ZnS: Cu, Al phosphor was used for the green phosphor. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 7. The luminance life according to the present invention was as good as in (Example 7).

MIM type electron source display device (6):
The MIM type electron source display device of the present invention is shown in FIG. In particular, inside the face plate 2, there is a fluorescent film 3 in which ZnSrS: Ag, Al phosphor (60% by weight) and Y ₂ SiO ₅ : Ce phosphor (40% by weight) are mixed as a blue fluorescent film. A Y ₂ O ₃ : Eu phosphor was used for the red phosphor film, and a ZnS: Cu, Al phosphor was used for the green phosphor. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 7. The luminance life according to the present invention was as good as in (Example 7).

MIM type electron source display device (7):
The MIM type electron source display device of the present invention is shown in FIG. In particular, a hexagonal ZnS: Ag, Cu, Al phosphor (60 wt%) and a (Y, Gd) ₂ SiO ₅ : Ce phosphor (40 wt%) are mixed inside the face plate 2 as a blue phosphor film. There is a fluorescent film 3. A Y ₂ O ₃ : Eu phosphor was used for the red phosphor film, and a Y ₂ SiO ₅ : Tb phosphor was used for the green phosphor. Further, in order to reduce the resistance of the phosphor, a conductive substance In ₂ O ₃ was mixed into the phosphor film. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 7. The luminance life according to the present invention was as good as in (Example 7).

MIM type electron source display device (Part 8):
The MIM type electron source display device of the present invention is shown in FIG. In particular, inside the face plate 2, there is a fluorescent film 3 having a layer of cubic ZnS: Ag, Al phosphor and a layer of (Y, Gd) ₂ SiO ₅ : Ce phosphor as a blue phosphor film. A Y ₂ O ₃ : Eu phosphor was used for the red phosphor film, and a Y ₂ SiO ₅ : Tb phosphor was used for the green phosphor. Further, in order to reduce the resistance of the phosphor, a conductive substance In ₂ O ₃ was mixed into the phosphor film. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 7. The luminance life according to the present invention was as good as in (Example 7).

Spindt-type electron source display device (1):
A Spindt-type electron source display device of the present invention is shown in FIG. The Spindt-type electron source display device 19 includes a face plate 2, a Spindt-type electron source 18, and a rear plate 7. The Spindt-type electron source 18 includes a cathode 13, a resistance film 14, an insulating film 15, a gate 16, a conical metal ( Mo etc.) 17 is formed.

In particular, a blue phosphor film is formed inside the face plate 2 by mixing cubic ZnS: Ag, Al sulfurating phosphor (70 wt%) and Y ₂ SiO ₅ : Ce phosphor (30 wt%). There is a fluorescent film 3. The average particle size of the phosphors was 6 μm. A Y ₂ O ₃ : Eu phosphor was used for the red phosphor film, and a Y ₂ SiO ₅ : Tb phosphor was used for the green phosphor film. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 7. The luminance life according to the present invention was as good as in (Example 7).

Spindt-type electron source display device (2):
A Spindt-type electron source display device of the present invention is shown in FIG. In particular, a phosphor film 3 in which hexagonal ZnS: Ag, Al sulfuration treatment phosphor (50 wt%) and Y ₂ SiO ₅ : Ce phosphor (50 wt%) are mixed as a blue phosphor film inside the face plate 2. There is. A Y ₂ O ₃ : Eu phosphor was used for the red phosphor film, and a Y ₂ SiO ₅ : Tb phosphor was used for the green phosphor. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 7. The luminance life according to the present invention was as good as in (Example 7).

Spindt-type electron source display device (Part 3):
A Spindt-type electron source display device of the present invention is shown in FIG. In particular, a cubic ZnS: Ag, Cl sulfurating treatment phosphor (90 wt%) and (Y, Gd) ₂ SiO ₅ : Ce phosphor (10 wt%) are mixed as a blue phosphor film inside the face plate 2. There is a fluorescent film 3. Y ₂ O ₃ : Eu phosphor is used for the red phosphor film, and cubic ZnS: Cu, Al sulfurating phosphor (50 wt%) and Y ₂ SiO ₅ : Tb phosphor (50 wt%) are used for the green phosphor. ) Was used. Further, in order to reduce the resistance of the phosphor, a conductive substance In ₂ O ₃ was mixed into the phosphor film. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 7. The luminance life according to the present invention was as good as in (Example 7).

Carbon nanotube type electron source display device (Part 1):
The carbon nanotube type electron source display device of the present invention is shown in FIG. The carbon nanotube type electron source display device 23 includes a face plate 2, a carbon nanotube electron source 22, and a rear plate 7, and the carbon nanotube type electron source 22 includes an electrode 20 and a carbon nanotube layer 21.

In particular, a blue phosphor film is formed inside the face plate 2 by mixing cubic ZnS: Ag, Al sulfurating phosphor (70 wt%) and Y ₂ SiO ₅ : Ce phosphor (30 wt%). There is a fluorescent film 3. The average particle size of the phosphors was 6 μm. A Y ₂ O ₃ : Eu phosphor was used for the red phosphor film, and a Y ₂ SiO ₅ : Tb phosphor was used for the green phosphor film. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 7. The luminance life according to the present invention was as good as in (Example 7).

Carbon nanotube electron source display device (2):
The carbon nanotube type electron source display device of the present invention is shown in FIG. In particular, inside the face plate 2, there is a fluorescent film 3 in which hexagonal ZnS: Ag, Al phosphor (50% by weight) and Y ₂ SiO ₅ : Ce phosphor (50% by weight) are mixed as a blue fluorescent film. . A Y ₂ O ₂ S: Eu phosphor was used for the red phosphor film, and a Y ₂ SiO ₅ : Tb phosphor was used for the green phosphor. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 7. The luminance life according to the present invention was as good as in (Example 7).

Carbon nanotube electron source display device (Part 3):
The carbon nanotube type electron source display device of the present invention is shown in FIG. In particular, on the inside of the face plate 2, as a blue fluorescent film, sulfurized cubic ZnS: Ag, Cl sulfurated phosphor (90 wt%) and (Y, Gd) ₂ SiO ₅ : Ce phosphor (10 There is a phosphor film 3 mixed with (wt%). Y ₂ O ₃ : Eu phosphor is used for the red phosphor film, and cubic ZnS: Cu, Al sulfurating phosphor (50 wt%) and Y ₂ SiO ₅ : Tb phosphor (50 wt%) are used for the green phosphor. ) Was used. Further, in order to reduce the resistance of the phosphor, a conductive substance In ₂ O ₃ was mixed into the phosphor film. The method for forming the fluorescent film, the black conductive material 1 and the metal back (not shown) is the same as in Example 1. The luminance life according to the present invention was as good as in Example 1.

The graph which shows the emission spectrum of the fluorescent film of this invention. The graph which shows the chromaticity-irradiation current amount change of the fluorescent film of this invention. The graph which shows the relative luminance-irradiation current amount change of the fluorescent film of this invention. The graph which shows the relative light emission energy-irradiation current amount change of the fluorescent film of this invention. The graph which shows the brightness | luminance maintenance factor curve of the fluorescent film of this invention. The graph which shows the chromaticity-irradiation current amount change of the fluorescent film of this invention. The graph which shows the relative luminance-irradiation current amount change of the fluorescent film of this invention. The graph which shows the relative light emission energy-irradiation current amount change of the fluorescent film of this invention. The graph which shows the brightness | luminance maintenance factor curve of the fluorescent film of this invention. The schematic diagram which shows the principal part cross-section of the MIM type | mold electron source display apparatus of this invention. The schematic diagram which shows the principal part cross-section of the Spindt type | mold electron source display apparatus of this invention. The schematic diagram which shows the principal part cross-section of the carbon nanotube type | mold electron source display apparatus of this invention.

Explanation of symbols

1. Black conductive material (black matrix),
2 ... Face plate,
3 ... Fluorescent film,
7 ... Rear plate,
8 ... Lower electrode,
9: Insulating layer,
10 ... Upper electrode,
11 ... MIM type electron source,
12 ... MIM type electron source display device,
13 ... cathode,
14 ... resistive film,
15 ... Insulating film,
16 ... Gate,
17 ... conical metal,
18 ... Spindt type electron source,
19 ... Spindt type electron source display device,
20 ... Electrode,
21 ... carbon nanotube layer,
22 ... Carbon nanotube type electron source,
23 ... Carbon nanotube type electron source display device.

Claims (9)

A field emission display device comprising a face plate on which a fluorescent film is formed and an electron source for irradiating the fluorescent film with an electron beam, wherein the phosphor forming the fluorescent film uses ZnS as a base material An image display comprising a mixture of a phosphor having a light emission shoulder observed on the high energy side of the main emission of the emission spectrum of 0.3 eV and a phosphor having Y ₂ SiO ₅ as a base material apparatus. The composition of the phosphor using ZnS as a base material for forming the phosphor film has the general formula ZnS: M, N (where M is one of Cu, Ag, Au, or a mixture thereof, N is Al, The composition of the phosphor represented by Y ₂ SiO ₅ as a base material is represented by the general formula Y ₂ SiO ₅ : R (where R is Ce, 2. The image display device according to claim 1, wherein the image display device is represented by any one of Eu, Tb, and Tm, or a mixed element thereof.   2. The image display device according to claim 1, wherein the phosphor that uses ZnS as a base material for forming the phosphor film is a ZnS phosphor containing at least Ag as a luminescent center element.   2. The image display device according to claim 1, wherein the emission intensity of the shoulder portion of the emission spectrum of the phosphor made of ZnS as a base material is four times or more larger than the intensity fitted with a Gaussian curve. The phosphor film is a phosphor made of a mixed crystal by adding at least one element selected from the group consisting of Group IIa in the ZnS base crystal, or composed of Group IIIa in the Y ₂ SiO ₅ base crystal The image display device according to claim 1, comprising any one of phosphors added with at least one element selected from the group to form a mixed crystal, or a phosphor obtained by mixing them.   2. The image display device according to claim 1, wherein the phosphor constituting the phosphor film contains at least one trace impurity selected from the group consisting of Group Ia, Group VIIb, and rare earth. _2. The image display device according to claim 1, wherein the mixing ratio of the Y ₂ SiO ₅ phosphor to the ZnS phosphor forming the phosphor film is in the range of 10 wt% to 50 wt%. The image display device according to claim 1, wherein the ZnS phosphor forming the phosphor film is annealed in a sulfur containing atmosphere at a processing temperature of 100 ° C to 600 ° C.   2. The image display device according to claim 1, wherein the surface of the phosphor particles constituting the phosphor film is covered with a translucent conductive film containing a translucent conductive substance.

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