JP2005036111A - Phosphor for display device and method for producing the same, and field emission display device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the deterioration of emission luminance due to electron beams of high current density in a zinc sulfide phosphor used for a display device such as FED. <P>SOLUTION: The phosphor for a display device has ZnS phosphor particles in which at least a part of the surface thereof is covered with a layer of In<SB>2</SB>O<SB>3</SB>. The method for producing such a phosphor comprises the steps of: adding a ZnS phosphor into an aqueous In salt solution to form an In(OH)<SB>3</SB>layer from the In salt on a surface of phosphor particles; and subjecting the phosphor to heat treatment (baking) to convert the In(OH)<SB>3</SB>layer to an In<SB>2</SB>O<SB>3</SB>layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a phosphor for a display device, a method for manufacturing the same, and a field emission display device using the same.

  With the advent of the multimedia era, display devices, which are core devices of digital networks, are required to have large screens, high definition, and compatibility with various sources such as computers.

  Among display devices, field emission display devices (field emission display; FED) using electron emission elements such as field emission cold cathode elements are large screens capable of displaying various information in a precise and high definition. As a thin and thin digital device, research and development have been actively conducted in recent years.

  The FED has the same basic display principle as a cathode ray tube (CRT), and excites a phosphor with an electron beam to emit light. However, in the FED, the acceleration voltage (excitation voltage) of the electron beam is 3 to 15 kV, which is lower than that of the CRT, and the current density due to the electron beam is high. At present, sufficient knowledge has not been obtained about the light emission characteristics of the phosphor under such low voltage / high current density excitation.

  In the FED, the phosphor constituting the phosphor film is required to have resistance against a high current density electron beam. With respect to such points, it is known that the deterioration of luminance due to electron beam impact can be suppressed by changing the crystal structure of the zinc sulfide phosphor from cubic to hexagonal. (For example, see Patent Document 1)

  However, although hexagonal zinc sulfide phosphors are effective in suppressing luminance degradation due to high current density electron beams, the problem is that the emission color shifts to the short wavelength side by making the crystal structure hexagonal. Had. Therefore, there is a strong demand for realizing a high-luminance blue-emitting phosphor and green-emitting phosphor for FED.

  In particular, in order to improve the white luminance, it is most important to improve the luminance of the green light-emitting phosphor. To obtain a highly saturated white, the luminance is improved while increasing the color purity (chromaticity) of blue. It was requested to plan.

  Conventionally, as blue phosphors for FEDs, zinc sulfide phosphors (ZnS: Ag, Al) using silver (Ag) and aluminum (Al) as activators have been used as fluorescence with the highest luminance. However, phosphors based on zinc sulfide have a problem in that they tend to be deteriorated by an electron beam having a high current density, and the light emission luminance tends to be lowered.

  On the other hand, for phosphors for display devices (low voltage phosphors) that excite the phosphor film with an electron beam having a low acceleration voltage such as FED, the surface of the phosphor matrix (ZnS) is coated with a metal salt or metal oxide. Then, a technique of doping an activator on the surface of the phosphor matrix by heat treatment is known (see Patent Document 2). Here, an activator such as Mn, Cu, Au, or Ag is doped only near the surface of the phosphor matrix.

However, the activator doping technique described in Patent Document 2 only increases the light emission efficiency of a low-voltage electron beam with a shallow penetration depth, and the brightness of a zinc sulfide phosphor with a high current density electron beam. Deterioration could not be suppressed sufficiently.
JP 2002-226847 A (page 2-3) Japanese Patent No. 2914631 (Japanese Patent Laid-Open No. 10-338870)

  The problem to be solved by the present invention is that the emission luminance of a zinc sulfide phosphor used in a display device such as a field emission display (FED) deteriorates with time due to excitation of a high current density electron beam. It is.

The inventors of the present invention have disclosed that oxides of metals such as yttrium (Y), aluminum (Al), and magnesium (Mg) as well as indium are formed on the surface of zinc sulfide phosphor particles used in display devices such as FEDs. As a result of investigating the change in light emission luminance by forming a layer and exciting it for a long time with an electron beam of low voltage and high current density, the deterioration in luminance is significant only when an indium oxide (In ₂ O ₃ ) layer is formed. I found it to be improved. The present invention has been made based on such findings.

The phosphor for a display device of the present invention is characterized in that at least a part of the surface of the zinc sulfide phosphor particles is covered with a layer of indium oxide (In ₂ O ₃ ).

A method of manufacturing a display device phosphor of the present invention, at least a portion of the surface of the zinc sulfide phosphor particles, a method of manufacturing a display device for a phosphor covered by a layer of indium oxide (In 2 _{O 3)} A step of forming an indium hydroxide layer on the surface of the phosphor particles by making the solution obtained by adding the zinc sulfide phosphor in an aqueous solution of an indium salt alkaline, and forming the indium hydroxide layer The zinc sulfide phosphor is heat treated to convert the indium hydroxide into indium oxide.

  Furthermore, the field emission display device of the present invention irradiates a fluorescent film including a blue light emitting phosphor layer, a green light emitting phosphor layer, and a red light emitting phosphor layer, and an electron beam having an acceleration voltage of 15 kV or less. A field emission display device comprising: an electron source that emits light; and an envelope that vacuum-seals the electron source and the phosphor film. Is included as at least one of the blue light-emitting phosphor and the green light-emitting phosphor.

  According to the phosphor for a display device of the present invention, it is possible to improve luminance deterioration with time due to excitation of electron beams with low voltage and high current density, and also to emit light (emission color) required for a light emission component for FED. Degree) can be satisfied. Therefore, by using such a phosphor, an FED with improved display characteristics such as color reproducibility and reliability can be provided, in response to increasing the current density of the electron beam that excites the phosphor film. It becomes possible to do.

  Hereinafter, modes for carrying out the present invention will be described.

An embodiment of the present invention is a phosphor for a display device that is excited by an electron beam having a low voltage and a high current density, and at least a part of the surface of the zinc sulfide phosphor particle is a layer of indium oxide (In ₂ O ₃ ). It is covered with.

  As the zinc sulfide phosphor, a phosphor based on zinc sulfide that emits blue or green light when irradiated with an electron beam having an acceleration voltage of 15 kV or less (for example, 3 to 15 kV) is used. In such a zinc sulfide phosphor, a desired luminescent color can be obtained based on the type and amount of activator contained in zinc sulfide as the phosphor matrix. For example, by containing Ag and Al or Cl as an activator, a blue emission color can be obtained, and by containing Cu, Au and Al as an activator, a green emission color can be obtained. Can do.

Specific examples of the zinc sulfide phosphor of the blue light-emitting, the general formula: ZnS: Ag _a, Al _b
(In the formula, a and b are 1 × 10 ⁻⁵ ≦ a ≦ 2 × 10 ⁻³ g, 1 × 10 ⁻⁵ ≦ b ≦ 5 × 10 ⁻³ g with respect to 1 g of zinc sulfide which is a phosphor matrix. And phosphors having a composition substantially represented by the following formula:

Here, Ag is the 1st activator (main activator) which forms a luminescent center, and is 1 * 10 < ^-5 > -2 * 10 < ^-3 > g with respect to 1g of zinc sulfide which is a fluorescent substance base. It is preferable to make it contain in the range. Even if the content of the first activator is less than 1 × 10 ⁻⁵ g or more than 2 × 10 ⁻³ g with respect to 1 g of zinc sulfide, the emission luminance and emission chromaticity are lowered. The content of the first activator is more preferably in the range of 3 × 10 ^{−5 to} 1.5 × 10 ⁻³ g, more preferably 5 × 10 ⁻⁵ to 1 × 10, per 1 g of zinc sulfide. The range is ^-3 g.

Further, Al is a second activator (coactivator) that is directly excited by an electron beam, and the first activator emits light with the excitation energy of such a second activator. Thus, the emission luminance of the zinc sulfide phosphor (for example, ZnS: Ag) can be increased. The content of the second activator is preferably in the range of 1 × 10 ^{−5 to} 5 × 10 ⁻³ g with respect to 1 g of zinc sulfide which is a phosphor matrix. Even if the content of the second activator is less than 1 × 10 ⁻⁵ g or more than 5 × 10 ⁻³ g with respect to 1 g of zinc sulfide, the emission luminance decreases and the emission chromaticity is also low. to degrade. The content of the second activator is more preferably in the range of 5 × 10 ⁻⁵ to 2 × 10 ⁻³ g, more preferably 1 × 10 ⁻⁴ to 1 × 10, per 1 g of zinc sulfide. The range is ^-3 g.

Specific examples of the green-emitting zinc sulfide phosphor include a general formula: ZnS: Cu _c , Au _d , Al _e (where c, d and e are 1 × with respect to 1 g of zinc sulfide which is the phosphor host). 10 ^-5 ≤ c ≤ 1 x 10 ^-3 g, 0 ≤ d ≤ 2 x 10 ^-3 g, 1 x 10 ^-5 ≤ c + d ≤ 2 x 10 ^-3 g, 1 x 10 ^-5 ≤ e ≤ 5 x 10 ^And phosphors having a composition substantially represented by ^-3 g, respectively.

Cu or Au is the first activator (main activator) that forms the luminescent center, and Cu is 1 × 10 ⁻⁵ to 1 × 10 ⁻³ g with respect to 1 g of zinc sulfide as the phosphor base material. The range, Au, is preferably contained in the range of 0 to 2 × 10 ⁻³ g. When the content of the first activator is out of the above-described range, the light emission luminance and the light emission chromaticity are lowered. The first activator is either Cu or a combination of Cu and Au. When a combination of Cu and Au is applied, the total amount of these is 1 × 10 ⁻⁵ to 2 × 10 ⁻³ g. Adjust to be within the range.

The content of Cu as the first activator is more preferably 3 × 10 ^{−5 to} 5 × 10 ⁻⁴ g, more preferably 5 × 10 ⁻⁵ to 1 g of zinc sulfide. The range is 3 x 10 ^-4 g. The content of Au as the first activator is more preferably in a range of ^{5 × 10 -5 ~1.5 × 10 -3} g with respect to zinc sulfide 1g, more preferably 1 × 10 ^- The range is ⁴ to 1 × 10 ⁻⁵ g. Further, the total amount of Cu and Au is more preferably in the range of 5 × 10 ^{−5 to} 1.5 × 10 ⁻³ g, more preferably 1 × 10 ⁻⁴ to 1 × 10 ^{− with} respect to 1 g of zinc sulfide. It is in the range of ³ g.

Further, Al is a second activator (coactivator) that is directly excited by an electron beam, and the first activator emits light with the excitation energy of such a second activator. As a result, the luminance of the zinc sulfide phosphor (for example, ZnS: Cu or ZnS: Cu, Au) can be increased. The content of the second activator is preferably in the range of 1 × 10 ^{−5 to} 5 × 10 ⁻³ g with respect to 1 g of zinc sulfide which is a phosphor matrix. Even if the content of the second activator is less than 1 × 10 ⁻⁵ g or more than 5 × 10 ⁻³ g with respect to 1 g of zinc sulfide, the emission luminance decreases and the emission chromaticity is also low. to degrade. The content of the second activator is more preferably in the range of 5 × 10 ⁻⁵ to 2 × 10 ⁻³ g, more preferably 1 × 10 ⁻⁴ to 1 × 10 ^{− with} respect to 1 g of zinc sulfide. The range is ³ g.

  In the zinc sulfide phosphor of the embodiment, activators such as Ag and Al are uniformly dispersed in the zinc sulfide particles that are the phosphor matrix. Here, the state where the activator is uniformly dispersed in the phosphor matrix particles means that the concentration of the activator inside the phosphor matrix particles (concentration distribution in the depth direction from the surface) is measured. , An approximately constant concentration distribution. Such a phosphor can be obtained, for example, by a method in which a material for forming zinc sulfide as a phosphor matrix and a material for forming an activator are uniformly mixed and fired.

A layer of In ₂ O ₃ is formed on the surface of such zinc sulfide phosphor particles. The In ₂ O ₃ layer can increase the effect of preventing luminance deterioration by covering at least a part of the surface of the zinc sulfide phosphor particles, but it is more preferable to form the In ₂ O ₃ layer so as to cover the entire surface without any gap.

The thickness of the In ₂ O ₃ layer is not particularly limited, but the coating amount converted to In atoms is a value measured by ICP (inductively coupled plasma) emission spectrometry with respect to zinc atoms of zinc sulfide which is a phosphor matrix. It is preferably in the range of 0.1 to 1.0%, and in the range of 6.0 to 60.0% as measured by XPS analysis (X-ray photoelectron analysis). When the coverage of In atoms is less than 0.1% by ICP emission analysis, there is no effect of improving the luminance deterioration of the phosphor. On the other hand, when the coverage of In atoms exceeds 1.0%, the In ₂ O ₃ layer has a large effect of blocking the penetration of the electron beam, which is not preferable because the luminance is lowered. The coverage of In atoms can be adjusted by changing the thickness of the In ₂ O ₃ layer formed by changing the amount of In salt to be added in the formation of the In ₂ O ₃ layer described later. it can.

  The phosphor for display device according to the above-described embodiment can be manufactured, for example, as follows.

  First, a predetermined amount of activator raw material is added to the zinc sulfide raw material that is the phosphor base, and a flux such as potassium chloride or magnesium chloride is added as necessary, and these are wet mixed. Specifically, a phosphor raw material is dispersed in ion-exchanged water to form a slurry, and an activator raw material and a flux are added thereto and mixed with a conventional stirrer. The mixing time is set so that the activator is uniformly dispersed. Next, the slurry containing the phosphor raw material and the activator is transferred to a drying container such as a pad and dried with a conventional dryer to obtain a phosphor raw material.

  Such a phosphor raw material is filled in a heat-resistant container such as a quartz crucible together with an appropriate amount of sulfur and activated carbon. At this time, the dried phosphor raw material and sulfur are mixed using a blender or the like for about 30 to 180 minutes, and after filling the mixed material in a heat-resistant container, the surface is covered with sulfur. preferable. This is fired in a sulfide atmosphere such as a hydrogen sulfide atmosphere or a sulfur vapor atmosphere, or in a reducing atmosphere (for example, an atmosphere of 3 to 5% hydrogen-remaining nitrogen).

  The firing conditions are important in controlling the crystal structure of the phosphor matrix (ZnS), and the firing temperature is preferably in the range of 800 to 1200 ° C. in order to obtain the target crystal structure. If the firing temperature is less than 800 ° C., the crystal grains of zinc sulfide cannot be sufficiently grown. On the other hand, when the firing temperature exceeds 1200 ° C., the desorption of sulfur is noticeable and the luminance is lowered. Although the firing time depends on the set firing temperature, it is preferably 30 to 180 minutes.

  Next, the obtained fired product is washed with ion-exchanged water or the like, dried, and further subjected to sieving to remove coarse particles as necessary, whereby the activator is uniformly dispersed. A zinc sulfide phosphor (eg, ZnS: Ag, Al phosphor or ZnS: Cu, Al phosphor) powder is obtained.

Next, the zinc sulfide phosphor powder is added to an aqueous solution of an indium salt such as indium nitrate or indium chloride and stirred, and further a basic substance (for example, NH ₄ OH or NaOH) is added to adjust the pH of the aqueous solution. Is adjusted to 9.0 or more to form an indium hydroxide (In (OH)) ₃ ) layer on the surface of the zinc sulfide phosphor particles.

Next, after filtering and drying the phosphor, the dried product is heat-treated (baked). The heating is performed at a temperature of 400 to 550 ° C. (for example, about 450 ° C.) for 1 to 3 hours in an air atmosphere. By heating, indium hydroxide is dehydrated to become indium oxide (In ₂ O ₃ ). Thus, a phosphor in which the surface of the zinc sulfide phosphor particles is coated with the In ₂ O ₃ layer can be obtained with good reproducibility.

  In the above method, the temperature at which the generated hydroxide is dehydrated by heat treatment to become an oxide is lower in indium hydroxide than in hydroxides such as yttrium, aluminum, and magnesium. That is, it is only indium hydroxide that can be converted from hydroxide to oxide at a sufficiently low temperature (about 450 ° C.) at which the zinc sulfide phosphor does not cause luminance deterioration.

In the zinc sulfide phosphor having the In ₂ O ₃ layer manufactured in this way, the reason why the deterioration of the light emission luminance is improved by coating the surface of the zinc sulfide phosphor particles with the In ₂ O ₃ layer is not necessarily clear. However, since In ₂ O ₃ is chemically stable and is not easily deteriorated by an electron beam, it has an effect of suppressing disorder (a change in crystal structure) of atoms on the surface of the zinc sulfide phosphor due to the electron beam. It is thought that. In addition, although the In ₂ O ₃ layer suppresses the charging of the zinc sulfide phosphor surface, it can be considered that the light emission efficiency is prevented from being lowered, but the above reason is considered to be a larger factor.

  Using the zinc sulfide phosphor of the embodiment, a blue light emitting phosphor layer or a green light emitting phosphor layer can be formed by a known slurry method or printing method.

  According to the phosphor for display device of the embodiment, when used in a field emission display device (FED) that is excited with an electron beam having a low acceleration voltage of 5 to 15 kV and a high current density, the blue light emitting fluorescence. In addition, it is possible to satisfy the emission color (emission chromaticity) required for the blue light emission component or the green light emission component for FED, while suppressing deterioration of luminance of the body or the green light emission phosphor with time. In other words, it is possible to stably obtain high-luminance blue light emission or green light emission with the light emission chromaticity required for the blue light emission component or green light emission component for FED.

  Next, a field emission display device (FED) in which a blue phosphor layer or a green light emitting phosphor layer is formed using the phosphor for display device of the present invention will be described.

  FIG. 1 is a cross-sectional view showing a main configuration of an embodiment of an FED.

  In FIG. 1, reference numeral 1 denotes a face plate, which has a phosphor layer 3 formed on a transparent substrate such as a glass substrate 2. The phosphor layer 3 has a blue light-emitting phosphor layer, a green light-emitting phosphor layer, and a red light-emitting phosphor layer formed corresponding to the pixels, and the light-emitting layer 4 made of a black conductive material is separated between these layers. It has a structure. Of the phosphor layers of each color constituting the phosphor layer 3, the blue light emitting phosphor layer or the green light emitting phosphor layer is composed of the blue light emitting phosphor or the green light emitting phosphor of the above-described embodiment. The phosphor layers other than these can be composed of various known phosphors.

  The blue light-emitting phosphor layer, the green light-emitting phosphor layer, the red light-emitting phosphor layer, and the light absorption layer 4 that separates them are sequentially and repeatedly formed in the horizontal direction, and these phosphor layers 3 And the part in which the light absorption layer 4 exists becomes an image display area. Various patterns such as a dot shape or a stripe shape can be applied to the arrangement pattern of the phosphor layer 3 and the light absorption layer 4.

  A metal back layer 5 is formed on the phosphor layer 3. The metal back layer 5 is made of a metal film such as an Al film, and reflects the light traveling in the rear plate direction, which will be described later, among the light generated in the phosphor layer 3 to improve the luminance.

  Further, the metal back layer 5 has a function of imparting conductivity to the image display area of the face plate 1 to prevent electric charges from being accumulated, and serves as an anode electrode for the electron source of the rear plate. Further, the metal back layer 5 has a function of preventing the phosphor layer 3 from being damaged by ions generated by ionizing the gas remaining in the face plate 1 or the vacuum vessel (envelope) with an electron beam, Further, the gas generated from the phosphor layer 3 during use is prevented from being released into the vacuum container (envelope), and the vacuum degree is prevented from being lowered.

  On the metal back layer 5, a getter film 6 made of an evaporable getter material made of Ba or the like is formed. The getter film 6 efficiently adsorbs the gas generated during use.

  The face plate 1 and the rear plate 7 are arranged to face each other, and the space between them is hermetically sealed via the support frame 8. The support frame 8 is bonded to the face plate 1 and the rear plate 7 by a frit glass or a bonding material 9 made of In or an alloy thereof, and is surrounded by the face plate 1, the rear plate 7, and the support frame 8. A vacuum vessel as a container is configured.

  The rear plate 7 includes a substrate 10 made of an insulating substrate such as a glass substrate or a ceramic substrate, or a Si substrate, and a large number of electron-emitting devices 11 formed on the substrate 10. These electron-emitting devices 11 include, for example, a field emission cold cathode, a surface conduction electron-emitting device, and the like, and wirings (not shown) are provided on the surface of the rear plate 7 where the electron-emitting devices 11 are formed. That is, a large number of electron-emitting devices 11 are formed in a matrix according to the phosphor of each pixel, and wirings (XY wirings) crossing each other that drive the matrix-shaped electron-emitting devices 11 row by row. have. The support frame 8 is provided with a signal input terminal and a row selection terminal (not shown). These terminals correspond to the cross wiring (XY wiring) of the rear plate 7 described above. Further, when a flat plate-type FED is enlarged, there is a possibility that bending or the like may occur due to the thin flat plate shape. In order to prevent such deflection and to give strength against atmospheric pressure, a reinforcing member (atmospheric pressure support member, spacer) 12 may be appropriately disposed between the face plate 1 and the rear plate 7. Good.

  In such a color FED, since the phosphor for a display device of the present invention is used as a blue light-emitting phosphor layer or a green light-emitting phosphor layer that emits light by excitation with an electron beam, the deterioration of light emission luminance is improved and used. The service life can be greatly improved.

  Next, specific examples of the present invention will be described.

Example 1
A predetermined amount of silver nitrate (AgNO ₃ ) and aluminum nitrate (Al (NO ₃ ) ₃ .9H ₂ O) was added to zinc sulfide (ZnS) together with an appropriate amount of water, and the mixture was thoroughly mixed and dried. Appropriate amounts of sulfur and activated carbon were added to the obtained phosphor material, filled in a quartz crucible, and fired in a reducing atmosphere. Thereafter, the fired product was washed with water and dried, and further sieved to obtain a zinc sulfide phosphor (ZnS: Ag, Al) powder.

  The zinc sulfide phosphor powder was added to an aqueous solution containing indium nitrate and stirred, and NaOH, which is a basic substance, was added to adjust the pH of the aqueous solution to 9.0 or more. Thus, an indium hydroxide layer was formed on the surface of the zinc sulfide phosphor particles.

Next, after filtering and drying the phosphor, the dried product was heat-treated (baked) at a temperature of about 450 ° C. in an air atmosphere for 1.5 hours. Thus, an indium oxide (In ₂ O ₃ ) layer was coated and formed on the surface of the zinc sulfide phosphor particles. The indium oxide coating amount was 0.3% in terms of In atoms by the IPC emission analysis method with respect to zinc atoms of zinc sulfide, which is a phosphor matrix.

Next, a phosphor film was formed by a slurry method using the obtained blue light-emitting phosphor. As a comparative example, a phosphor film was formed using a cubic zinc sulfide phosphor (ZnS: Ag, Al). The phosphor films are formed by dispersing the phosphors obtained in Example 1 and the comparative example in aqueous solutions containing polyvinyl alcohol and the like to form slurries. These slurries are formed on a glass substrate by a spin coater (spin coater). This was done by coating on top. The film thickness of each phosphor film was adjusted to 3 × 10 ⁻³ mg / mm ³ by adjusting the rotation speed of the spin coater and the viscosity of the slurry.

Next, the emission luminance and emission chromaticity of the phosphor film thus obtained were examined. The light emission luminance was measured by irradiating each phosphor film with an electron beam having an acceleration voltage of 10 kV and a current density of 1.2 A / cm ² . The light emission luminance was determined as a relative value when the luminance of the phosphor film according to the comparative example was 100.

  The emission chromaticity was measured using SR-3 manufactured by Topcon as a chromaticity measuring instrument. The emission chromaticity was measured in a dark room where the chromaticity at the time of light emission was not affected from the outside. Table 1 shows the measurement results of emission luminance and emission chromaticity.

  As is apparent from Table 1, the blue light-emitting phosphor obtained in Example 1 has the same emission color as that of the comparative example when irradiated with an electron beam with a low acceleration voltage (15 kV or less) and a high current density. It is good and has the same luminance.

Further, the luminance deterioration characteristics of the phosphor films obtained in Example 1 and the comparative example were examined as follows. That is, each phosphor film was continuously irradiated with an electron beam having an acceleration voltage of 10 kV and a current density of 1.2 A / cm ² , and the relationship between the total amount of charges input by the electron beam irradiation and the emission luminance was examined. A graph showing this relationship is shown in FIG. Then, from this graph, the input charge amount until the light emission luminance reached the initial 50% was examined. Compared result, whereas the phosphor layer of Example 1 is 1050C / cm ^2, the phosphor in the film 350C / cm ² next to the comparative example, the comparative examples luminescence life of the phosphor film of Example 1 It was confirmed that the improvement was about 3 times.

Example 2
Using the blue light-emitting phosphor, the green light-emitting phosphor (cubic ZnS: Cu, Al phosphor), and the red light-emitting phosphor (Y ₂ O ₂ S: Eu phosphor) obtained in Example 1, respectively. A phosphor layer was formed on a glass substrate to obtain a face plate. The face plate and the rear plate having a large number of electron-emitting devices were assembled through a support frame, and the gap between them was hermetically sealed while evacuating. It was confirmed that the FED obtained in this way was excellent in color reproducibility and exhibited good display characteristics even after being driven at room temperature and rated operation for 1000 hours.

  According to the phosphor for a display device of the present invention, when used in a field emission display device (FED) excited by an electron beam having a low acceleration voltage of 5 to 15 kV and a high current density, It is possible to satisfy the emission color (emission chromaticity) required for the blue light emission component or the green light emission component for FED after suppressing the luminance deterioration of the green light emission phosphor with time. In other words, it is possible to stably obtain high-luminance blue light emission or green light emission with the light emission chromaticity required for the blue light emission component or green light emission component for FED.

It is sectional drawing which shows the structural example of the field emission display (FED) as one Embodiment of this invention. In Example 1 of this invention, it is a graph which shows the relationship between the electric charge total thrown by electron beam irradiation, and light emission luminance.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Face plate, 2 ... Glass substrate, 3 ... Phosphor layer, 4 ... Light absorption layer, 5 ... Metal back layer, 6 ... Getter film, 7 ... Rear plate, 8 ... Support frame, 11 ... Electron emission element.

Claims (6)

A phosphor for display device, wherein at least a part of the surface of the zinc sulfide phosphor particles is covered with a layer of indium oxide (In ₂ O ₃ ).   2. The fluorescence for a display device according to claim 1, wherein the zinc sulfide phosphor is a zinc sulfide phosphor (ZnS: Ag, Al) containing silver (Ag) and aluminum (Al) as activators. body.   The indium oxide coating amount is 0.1 to 1.0% by the ICP emission analysis method with respect to zinc atoms of zinc sulfide, which is the matrix of the phosphor, in terms of indium (In) atoms, The phosphor for a display device according to claim 1 or 2, wherein the content is 6.0 to 60.0% by XPS analysis. A method for producing a phosphor for display device in which at least a part of the surface of zinc sulfide phosphor particles is covered with a layer of indium oxide (In ₂ O ₃ ),
The step of forming a layer of indium hydroxide on the surface of the phosphor particles by making the solution obtained by adding the zinc sulfide phosphor in an aqueous solution of indium salt alkaline, and the indium hydroxide layer formed A method for producing a phosphor for a display device, comprising a step of heat-treating a zinc sulfide phosphor to convert the indium hydroxide into indium oxide.   The method for producing a phosphor for a display device according to claim 4, wherein the heat treatment is performed at a temperature of 400 to 550 ° C. A fluorescent film including a blue-emitting phosphor layer, a green-emitting phosphor layer, and a red-emitting phosphor layer; an electron source that emits light by irradiating the phosphor film with an electron beam having an acceleration voltage of 15 kV or less; and the electron source A field emission display device comprising an envelope for vacuum-sealing the fluorescent film;
The field emission display device, wherein the phosphor film includes the phosphor for display device according to any one of claims 1 to 3 as at least one of the blue light-emitting phosphor and the green light-emitting phosphor. .

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