JP2006335967A - Phosphor for displaying device and electric field-emission type displaying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a phosphor for a displaying device, having a high color purity and improved with emitted light luminance. <P>SOLUTION: This phosphor for the displaying device is provided by consisting mainly of a ternary compound phosphor of using Ce or Eu as an activating agent, and emitting light by being excited with an electron beam having ≤15 kV accelerating electric voltage. The first element constituting the ternary compound is at least 1 kind of an element selected from Na, Ba, Sr and Ca, the second element is Y or Si and the third element is S. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a phosphor for a display device 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, but the electron beam acceleration voltage (excitation voltage) is lower than that of a CRT. In addition, the current density per unit time by the electron beam is also low. Therefore, in order to obtain sufficient luminance, a very long excitation time is required as compared with CRT. This means that the input charge amount per unit area for obtaining a predetermined luminance must be increased, which promotes the deterioration of the lifetime. For this reason, the use of a phosphor based on zinc sulfide, which has been conventionally used for CRTs, does not provide sufficient light emission brightness and lifetime. (For example, see Patent Document 1)
JP 2002-226847 A

  The present invention has been made to solve such a problem, and an object of the present invention is to provide a phosphor for a display device having high emission luminance. Another object of the present invention is to provide a field emission display device (FED) having high luminance and excellent display characteristics such as color reproducibility by using such a phosphor.

  The phosphor for a display device of the present invention uses cerium (Ce) or europium (Eu) as an activator, and includes a first element belonging to Group I or II of the periodic table, a second element, and a VI group. The phosphor is mainly composed of a ternary compound phosphor combining the third elements belonging to the phosphor, and emits light when excited by an electron beam having an acceleration voltage of 15 kV or less. The first element is made of Na, Ba, Sr, or Ca. It is at least one element selected, wherein the second element is yttrium (Y) or silicon (Si), and the third element is sulfur (S).

  The field emission display device according to the present invention includes a phosphor layer including a blue-emitting phosphor layer, a green-emitting phosphor layer, and a red-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 for emitting light; and an envelope for vacuum-sealing the electron source and the phosphor layer, wherein the phosphor layer is for the display device according to the present invention described above. It contains a phosphor.

  The phosphor for a display device of the present invention comprises a ternary compound in which at least one element selected from Na and Ba, Sr, and Ca, yttrium (Y) or silicon (Si), and sulfur (S) are combined. Since cerium (Ce) or europium (Eu), which has a high probability of transition of the electronic state from the ground level to the excited level, is contained as an activator as a matrix, in the irradiation of an electron beam with an acceleration voltage of 15 kV or less Excellent luminous efficiency is realized, and high luminance is obtained. Further, light emission with high color purity can be obtained as compared with zinc sulfide phosphors and oxysulfide phosphors conventionally used as CRT phosphors. Therefore, by using this phosphor for a display device, a thin flat display device such as an FED having high luminance and good display characteristics can be realized.

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

  In the first embodiment of the present invention, cerium (Ce) is used as an activator, and Ba as a first element, silicon (Si) as a second element, and sulfur (S) as a third element are used. This phosphor is mainly composed of a combined ternary compound and is excited by an electron beam having an acceleration voltage of 15 kV or less to emit blue light.

More specifically, it is a blue-emitting phosphor composed of cerium-activated barium thiosilicate substantially represented by the chemical formula: Ba ₂ SiS ₄ : Ce.

In the phosphor according to the first embodiment, Ce is an activator that forms a light emission center and has a high transition probability, so that the light emission efficiency is high. Ce, which is an activator, is preferably contained in a range of 0.1 to 5.0 mol% with respect to barium thiosilicate (Ba ₂ SiS ₄ ) that is a base material of the phosphor. A more preferable Ce concentration is 0.5 to 3.0 mol%. If the Ce concentration is outside this range, the light emission luminance and light emission chromaticity decrease, which is not preferable.

  The cerium-activated barium thiosilicate phosphor that is the first embodiment of the present invention can be produced, for example, by the following method.

That is, a raw material containing an element constituting a phosphor matrix and an activator or a compound containing the element is weighed so as to have a desired composition (Ba ₂ SiS ₄ : Ce), and further potassium chloride or magnesium chloride. Etc. are added as needed, and these are mixed by a dry type. Specifically, a predetermined amount of barium sulfide and silicon are mixed, and an appropriate amount of activator and flux are added to obtain a phosphor material. Instead of barium sulfide, an acidic barium raw material such as barium sulfate may be used.

  Next, such a phosphor material is filled in a heat-resistant container such as a quartz crucible together with appropriate amounts of sulfur and activated carbon. At this time, it is preferable to add and mix sulfur by using a blender or the like to mix more than the phosphor raw material, and after filling the mixed material into a heat-resistant container, the surface is covered with sulfur. This is fired in a sulfide atmosphere such as a hydrogen sulfide atmosphere, a sulfur vapor atmosphere, or a reducing atmosphere (for example, an atmosphere of 3 to 5% hydrogen-remaining nitrogen).

Firing conditions are important in controlling the crystal structure of the phosphor matrix (Ba ₂ SiS ₄ ). The firing temperature is preferably in the range of 900 to 1200 ° C. Although the firing time depends on the set firing temperature, it is preferably 15 to 120 minutes, and after firing is preferably cooled in the same atmosphere as firing. Thereafter, the obtained fired product is washed with ion-exchanged water and dried, and then subjected to sieving for removing coarse particles as necessary, whereby a cerium-activated barium thiosilicate phosphor (Ba _2). SiS ₄ : Ce) can be obtained.

  The blue light-emitting phosphor according to the first embodiment thus obtained achieves good light emission efficiency by irradiation with an electron beam having an acceleration voltage of 15 kV or less, and high emission luminance is obtained. Further, although the color purity is slightly inferior to that of the zinc sulfide phosphor conventionally used as a blue light emitting phosphor for CRT, it is considerably better than the known cerium activated phosphor. Therefore, a high-intensity FED can be realized by using this blue phosphor.

In the second embodiment of the present invention, europium (Eu) is used as an activator, and Na, which is the first element, silicon (Si), which is the second element, and sulfur (S), which is the third element, are used. This phosphor is mainly composed of a combined ternary compound and is excited by an electron beam having an acceleration voltage of 15 kV or less to emit blue light. More specifically, it is a blue light emitting phosphor composed of sodium thiosilicate substantially represented by the chemical formula: Na ₄ SiS ₄ : Eu.

In the phosphor of the second embodiment, Eu is an activator that forms a light emission center, and has a high transition probability, so that the light emission efficiency is high. Eu, which is an activator, is preferably contained in a range of 0.2 to 10 mol% with respect to sodium thiosilicate (Na ₄ SiS ₄ ) that is a base material of the phosphor. A more preferable Eu content is 1 to 5 mol%. If the Eu concentration is outside this range, the light emission luminance and light emission chromaticity are lowered, which is not preferable.

  The europium activated sodium thiosilicate phosphor, which is the second embodiment of the present invention, can be produced, for example, by the method shown below.

That is, a raw material containing an element constituting a phosphor base material and an activator or a compound containing the element is weighed so as to have a desired composition (Na ₄ SiS ₄ : Eu), and further potassium chloride or magnesium chloride. Etc. are added as needed, and these are mixed by a dry type. Specifically, a predetermined amount of sodium sulfide and silicon are mixed, and an appropriate amount of activator and flux are added to obtain a raw material for the phosphor. An acidic sodium raw material such as sodium sulfate may be used instead of sodium sulfide.

  Next, such a phosphor material is filled in a heat-resistant container such as a quartz crucible together with appropriate amounts of sulfur and activated carbon. At this time, it is preferable to add and mix sulfur by using a blender or the like to mix more than the phosphor raw material, and after filling the mixed material into a heat-resistant container, the surface is covered with sulfur. This is fired in a sulfide atmosphere such as a hydrogen sulfide atmosphere, a sulfur vapor atmosphere, or a reducing atmosphere (for example, an atmosphere of 3 to 5% hydrogen-remaining nitrogen).

Firing conditions are important in controlling the crystal structure of the phosphor matrix (Na ₄ SiS ₄ ). The firing temperature is preferably in the range of 900 to 1200 ° C. Although the firing time depends on the set firing temperature, it is preferably 15 to 120 minutes, and after firing is preferably cooled in the same atmosphere as firing. Thereafter, the fired product obtained is washed with ion-exchanged water and dried, and then subjected to sieving to remove coarse particles as necessary, whereby europium-activated sodium thiosilicate phosphor (Na ₄ SiS ₄ : Eu) can be obtained.

  The blue light-emitting phosphor of the second embodiment thus obtained achieves good light emission efficiency by irradiation with an electron beam having an acceleration voltage of 15 kV or less, and high emission luminance is obtained. Further, it has the same color purity as the zinc sulfide phosphor conventionally used as a blue light emitting phosphor for CRT. Therefore, by using this blue phosphor, an FED having high luminance and high color purity can be realized.

In the third embodiment of the present invention, europium (Eu) is used as an activator, and at least one element selected from Ba, Sr, and Ca, silicon (Si) as the second element, and the third element It is a phosphor that mainly emits green light when excited by an electron beam having an accelerating voltage of 15 kV or less. More specifically, it is a green-emitting phosphor composed of europium-activated barium strontium thiosilicate substantially represented by the chemical formula: (Ba, Sr) ₂ SiS ₄ : Eu.

  In the phosphor of the third embodiment, Eu is an activator that forms a light emission center and has a high transition probability, so that the light emission efficiency is high. Eu as an activator is preferably contained in a range of 0.2 to 10 mol% with respect to the base material, barium / strontium thiosilicate. A more preferable Eu content is 1 to 5 mol%. If the Eu concentration is outside this range, the light emission luminance and light emission chromaticity are lowered, which is not preferable.

  The europium-activated barium / strontium thiosilicate phosphor that is the third embodiment of the present invention can be produced by, for example, the following method.

That is, a raw material containing an element constituting the phosphor matrix and an activator or a compound containing the element is weighed so as to have a desired composition ((Ba, Sr) ₂ SiS ₄ : Eu), and further chlorinated. A flux such as potassium or magnesium chloride is added if necessary, and these are mixed by a dry method. Specifically, a predetermined amount of barium sulfide, strontium sulfide and silicon are mixed, and an appropriate amount of activator and flux are added to obtain a raw material for the phosphor. Instead of barium sulfide and strontium sulfide, acidic barium raw materials such as barium sulfate and strontium sulfate and acidic strontium raw materials may be used.

  Next, such a phosphor material is filled in a heat-resistant container such as a quartz crucible together with appropriate amounts of sulfur and activated carbon. At this time, it is preferable to add and mix sulfur by using a blender or the like to mix more than the phosphor raw material, and after filling the mixed material into a heat-resistant container, the surface is covered with sulfur. This is fired in a sulfide atmosphere such as a hydrogen sulfide atmosphere, a sulfur vapor atmosphere, or a reducing atmosphere (for example, an atmosphere of 3 to 5% hydrogen-remaining nitrogen).

Firing conditions are important in controlling the crystal structure of the phosphor matrix ((Ba, Sr) ₂ SiS ₄ ). The firing temperature is preferably in the range of 900 to 1200 ° C. Although the firing time depends on the set firing temperature, it is preferably 15 to 120 minutes, and after firing is preferably cooled in the same atmosphere as firing. Thereafter, the obtained fired product is washed with ion-exchanged water and dried, followed by sieving to remove coarse particles as necessary, thereby enabling europium-activated barium / strontium thiosilicate phosphor ( (Ba, Sr) ₂ SiS ₄ : Eu) can be obtained.

  The green light emitting phosphor of the third embodiment obtained in this way can achieve good light emission efficiency by irradiation with an electron beam having an acceleration voltage of 15 kV or less, and high emission luminance can be obtained. Further, the color purity is higher than that of a zinc sulfide phosphor conventionally used as a green light emitting phosphor for CRT. Therefore, by using this green phosphor, an FED having high luminance and high color purity can be realized.

In the fourth embodiment of the present invention, europium (Eu) is used as an activator, at least one element selected from Ba, Sr, and Ca, yttrium (Y) as the second element, and the third element. It is a phosphor that mainly emits red light when excited by an electron beam having an acceleration voltage of 15 kV or less. More specifically, it is a red light-emitting phosphor composed of europium-activated strontium thioyttrium substantially represented by the chemical formula: SrY ₂ S ₄ : Eu.

In the phosphor of the fourth embodiment, Eu is an activator that forms a light emission center and has a high transition probability, so that the light emission efficiency is high. Eu as an activator is preferably contained in a range of 0.1 to 10 mol% with respect to strontium thioyttrium (SrY ₂ S ₄ ) as a base material. A more preferable Eu content is 1 to 5 mol%. If the Eu concentration is outside this range, the light emission luminance and light emission chromaticity are lowered, which is not preferable.

  The europium-activated strontium thioyttrium phosphor that is the fourth embodiment of the present invention can be produced, for example, by the following method.

That is, a raw material containing an element constituting a phosphor base and an activator or a compound containing the element is weighed so as to have a desired composition (SrY ₂ S ₄ : Eu), and further potassium chloride or magnesium chloride. Etc. are added as needed, and these are mixed by a dry type. Specifically, a predetermined amount of strontium sulfide and yttrium are mixed, and an appropriate amount of activator and flux are added to obtain a phosphor material. Instead of strontium sulfide, an acidic strontium raw material such as strontium sulfate may be used.

  Next, such a phosphor material is filled in a heat-resistant container such as a quartz crucible together with appropriate amounts of sulfur and activated carbon. At this time, it is preferable to add and mix sulfur by using a blender or the like to mix more than the phosphor raw material, and after filling the mixed material into a heat-resistant container, the surface is covered with sulfur. This is fired in a sulfide atmosphere such as a hydrogen sulfide atmosphere, a sulfur vapor atmosphere, or a reducing atmosphere (for example, an atmosphere of 3 to 5% hydrogen-remaining nitrogen).

Firing conditions are important in controlling the crystal structure of the phosphor matrix (SrY ₂ S ₄ ). The firing temperature is preferably in the range of 900 to 1200 ° C. Although the firing time depends on the set firing temperature, it is preferably 15 to 120 minutes, and after firing is preferably cooled in the same atmosphere as firing. Thereafter, the fired product obtained is washed with ion-exchanged water and dried, and then subjected to sieving to remove coarse particles as necessary, whereby a europium activated strontium thioyttrium phosphor (SrY _2). S ₄ : Eu) can be obtained.

  The red light-emitting phosphor of the fourth embodiment obtained in this way achieves good light emission efficiency by irradiation with an electron beam with an acceleration voltage of 15 kV or less, and high emission luminance is obtained. Further, the color purity is higher than that of an oxysulfide phosphor conventionally used as a red light emitting phosphor for CRT. Therefore, by using this red phosphor, an FED having high luminance and high color purity can be realized.

  Using at least one of the phosphors of the first to fourth embodiments of the present invention, the phosphor layer can be formed by a known printing method or slurry method. In order to form a phosphor layer by a printing method, a paste prepared by mixing the phosphor of the embodiment with a binder solution made of, for example, polyvinyl alcohol, n-butyl alcohol, ethylene glycol, water, or the like is used for screen printing. Apply on the substrate by the method. Next, for example, baking is performed to decompose and remove the binder component by heating at a temperature of 500 ° C. for 1 hour.

  In the slurry method, the phosphor of the embodiment is mixed with a photosensitive material such as pure water, polyvinyl alcohol, and ammonium dichromate, a surfactant, and the like to prepare a phosphor slurry. After coating and drying on the substrate, exposure and development are performed by irradiating with ultraviolet rays and the like, followed by drying. In this way, a phosphor layer having a predetermined pattern can be formed.

  Next, using at least one of the phosphors of the first to fourth embodiments, an electric field in which at least one of a blue light-emitting phosphor layer, a green light-emitting phosphor layer, and a red light-emitting phosphor layer is formed. An emission display (FED) 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. At least one of the blue light-emitting phosphor layer, the green light-emitting phosphor layer, and the red light-emitting phosphor layer is formed using at least one of the phosphors of the first to fourth embodiments described above. .

  The thickness of the phosphor layer formed of the phosphors of these embodiments is desirably 1 to 10 μm, more preferably 6 to 10 μm. The reason why the thickness of the phosphor layer is limited to 1 μm or more is that it is difficult to form a phosphor layer in which the phosphor particles are uniformly arranged with a thickness of less than 1 μm. On the other hand, if the thickness of the phosphor layer exceeds 10 μm, the light emission luminance is lowered and cannot be put to practical use. The phosphor layers other than the phosphor layer formed by the phosphors of the first to fourth embodiments can be formed using known phosphors, respectively. It is desirable that the phosphor layers of the respective colors have the same thickness so that no step is generated between the phosphor layers of the respective colors.

  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 improves the luminance by reflecting light traveling in the rear plate direction, which will be described later, from light generated in the phosphor layer 3.

  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 accumulating, 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, Furthermore, 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 formed of an evaporation type 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 the surface of the rear plate 7 on which the electron-emitting devices 11 are formed is provided with wiring (not shown). That is, a large number of electron-emitting devices 11 are formed in a matrix according to the phosphors 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 provide 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 this FED, at least one of the phosphor layers of each color that emits light when irradiated with an electron beam with an acceleration voltage of 15 kV or less is formed by at least one of the phosphors of the first to fourth embodiments. Since it is formed, the luminance and color purity are high, and the display characteristics are good. Next, specific examples of the present invention will be described.

Examples 1 and 2 (Preparation of blue-emitting phosphor)
A raw material containing an element constituting the phosphor matrix and an activator or a compound containing the element is weighed so as to have the composition shown in Table 1 (Ba ₂ SiS ₄ : Ce and Na ₄ SiS ₄ : Eu). Flux was added and mixed well. 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. The firing conditions were 1000 ° C. × 60 minutes. Thereafter, the obtained fired product is washed with water, dried, and further sieved to obtain a cerium activated phosphor (Ba ₂ SiS ₄ : Ce) (Example 1) and a europium activated phosphor (Na ₄ SiS ₄ : Eu). ) (Example 2) were obtained.

  Then, using the phosphor thus obtained, a phosphor layer having a thickness of 8 μm was formed by screen printing, and an aluminum metal back layer was further formed thereon by a lacquer method. Further, as Comparative Example 1, a phosphor layer was similarly formed using silver and aluminum-activated zinc sulfide phosphor (ZnS: Ag, Al), and an aluminum metal back layer was further formed thereon by a lacquer method. did.

Next, the emission luminance and emission chromaticity of the phosphor layers obtained in Examples 1 and 2 and Comparative Example 1 were examined. The light emission luminance was measured by irradiating each phosphor layer with an electron beam having an acceleration voltage of 10 kV and a current density of 20 mA / cm ² . And the light emission luminance was calculated | required as a relative value when the luminance of the fluorescent substance layer of the comparative example 1 was set to 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 clear from Table 1, the blue light-emitting phosphors obtained in Examples 1 and 2 were irradiated with an electron beam having a high acceleration current (15 kV or less) at a low acceleration voltage compared to that in Comparative Example 1. The light emission brightness is significantly improved. In addition, it can be seen that it has sufficiently good emission chromaticity.

Example 3 (Preparation of green light-emitting phosphor)
A raw material containing an element constituting the phosphor matrix and an activator or a compound containing the element is weighed so as to have the composition shown in Table 2 ((Ba, Sr) ₂ SiS ₄ : Eu), and the flux is measured. Added and mixed well. 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. The firing conditions were 1000 ° C. × 60 minutes. Thereafter, the obtained fired product was washed with water, dried and further sieved to obtain a europium activated phosphor ((Ba, Sr) ₂ SiS ₄ : Eu).

  Then, using the phosphor thus obtained, a phosphor layer having a thickness of 8 μm was formed by screen printing, and an aluminum metal back layer was further formed thereon by a lacquer method. Further, as Comparative Example 2, a phosphor layer was similarly formed using copper and aluminum-activated zinc sulfide phosphor (ZnS: Cu, Al), and an aluminum metal back layer was further formed thereon by a lacquer method. did.

Next, the light emission luminance and light emission chromaticity of the phosphor layers obtained in Example 3 and Comparative Example 2 were examined. The light emission luminance was measured by irradiating each phosphor layer with an electron beam having an acceleration voltage of 10 kV and a current density of 20 mA / cm ² . And the light emission brightness | luminance was calculated | required as a relative value when the brightness | luminance of the fluorescent substance layer of the comparative example 2 was set to 100. FIG. 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 2 shows the measurement results of light emission luminance and light emission chromaticity.

  From Table 2, the green light-emitting phosphor obtained in Example 3 has significantly higher emission luminance when irradiated with an electron beam having a low acceleration voltage (15 kV or less) and a high current density than that of Comparative Example 2. It can be seen that it has improved and good emission chromaticity.

Example 4 (Preparation of red-emitting phosphor)
A raw material containing an element constituting the phosphor matrix and an activator or a compound containing the element is weighed so as to have the composition shown in Table 3 (SrY ₂ S ₄ : Eu), and a flux is sufficiently added. Mixed. 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. The firing conditions were 1000 ° C. × 60 minutes. Thereafter, the obtained fired product was washed with water, dried and further sieved to obtain a europium activated phosphor (SrY ₂ S ₄ : Eu).

Then, using the phosphor thus obtained, a phosphor layer having a thickness of 8 μm was formed by screen printing, and an aluminum metal back layer was further formed thereon by a lacquer method. Further, as Comparative Example 3, a phosphor layer was similarly formed using europium-activated oxysulfide phosphor (Y ₂ O ₂ S: Eu), and an aluminum metal back layer was further formed thereon by a lacquer method. Formed.

Next, the light emission luminance and light emission chromaticity of the phosphor layers obtained in Example 4 and Comparative Example 3 were examined. The light emission luminance was measured by irradiating each phosphor layer with an electron beam having an acceleration voltage of 10 kV and a current density of 20 mA / cm ² . The emission luminance was determined as a relative value when the luminance of the phosphor layer of Comparative Example 3 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 3 shows the measurement results of light emission luminance and light emission chromaticity.

  From Table 3, the red light-emitting phosphor obtained in Example 4 has significantly higher emission luminance when irradiated with an electron beam having a low acceleration voltage (15 kV or less) and a high current density than that of Comparative Example 3. It can be seen that it has improved and good emission chromaticity.

Example 5
The blue light-emitting phosphor (Ba ₂ SiS ₄ : Ce) obtained in Example 1, the known green light-emitting phosphor (ZnS: Cu, Al), and the red light-emitting phosphor (Y ₂ O ₂ S: Eu) were respectively used. 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 produced in this way was excellent in color reproducibility including light emission luminance, and showed good luminance characteristics even after being driven at room temperature and rated operation for 1000 hours.

Example 6
The blue light-emitting phosphor (Na ₄ SiS ₄ : Eu) obtained in Example 2, the known green light-emitting phosphor (ZnS: Cu, Al), and the red light-emitting phosphor (Y ₂ O ₂ S: Eu) were respectively used. 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 produced in this way was excellent in color reproducibility including light emission luminance, and showed good luminance characteristics even after being driven at room temperature and rated operation for 1000 hours.

Example 7
The green light-emitting phosphor ((Ba, Sr) ₂ SiS ₄ : Eu) obtained in Example 3, the known blue light-emitting phosphor (ZnS: Ag, Al), and the red light-emitting phosphor (Y ₂ O ₂ S: Eu) was used, and a phosphor layer was formed on a glass substrate to form 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 produced in this way was excellent in color reproducibility including light emission luminance, and showed good luminance characteristics even after being driven at room temperature and rated operation for 1000 hours.

Example 8
Using the red light-emitting phosphor (SrY ₂ S ₄ : Eu) obtained in Example 4, the known blue light-emitting phosphor (ZnS: Ag, Al) and the green light-emitting phosphor (ZnS: Cu, Al), 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 produced in this way was excellent in color reproducibility including light emission luminance, and showed good luminance characteristics even after being driven at room temperature and rated operation for 1000 hours.

Example 9
In Example 4, the blue light-emitting phosphor (Ba ₂ SiS ₄ : Ce) obtained in Example 1, the green light-emitting phosphor ((Ba, Sr) ₂ SiS ₄ : Eu) obtained in Example 3, and Using the obtained red light emitting phosphors (SrY ₂ S ₄ : Eu), 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 produced in this way was excellent in color reproducibility including light emission luminance, and showed good luminance characteristics even after being driven at room temperature and rated operation for 1000 hours.

Example 10
In Example 4, the blue-emitting phosphor (Na ₄ SiS ₄ : Eu) obtained in Example 2 and the green-emitting phosphor ((Ba, Sr) ₂ SiS ₄ : Eu) obtained in Example 3 were used. Using the obtained red light emitting phosphors (SrY ₂ S ₄ : Eu), 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 produced in this way was excellent in color reproducibility including light emission luminance, and showed good luminance 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, it is possible to obtain light emission with high brightness and good color purity when irradiated with an electron beam having a low voltage and a high current density. Therefore, by using such a phosphor, a thin flat display device having high luminance and excellent display characteristics such as color reproducibility can be realized.

It is sectional drawing which shows schematically FED which is embodiment of this invention.

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 ternary that combines cerium (Ce) or europium (Eu) as an activator, and a first element belonging to Group I or II of the periodic table, a second element, and a third element belonging to Group VI A phosphor mainly composed of a compound phosphor, which emits light when excited by an electron beam having an acceleration voltage of 15 kV or less,
The first element is at least one element selected from Na, Ba, Sr, and Ca, the second element is yttrium (Y) or silicon (Si), and the third element is sulfur ( S) A phosphor for a display device.   A phosphor that uses Ce as an activator and emits blue light when excited by an electron beam with an acceleration voltage of 15 kV or less, wherein the first element is Ba and the second element is Si. The phosphor for display device according to claim 1.   A phosphor that uses Eu as an activator and emits blue light when excited by an electron beam with an accelerating voltage of 15 kV or less, wherein the first element is Na and the second element is Si. The phosphor for display device according to claim 1.   A phosphor that uses Eu as an activator and emits green light when excited by an electron beam with an acceleration voltage of 15 kV or less, and the first element is at least one element selected from Ba, Sr, and Ca, The phosphor for a display device according to claim 1, wherein the second element is Si.   A phosphor that uses Eu as an activator and emits red light when excited by an electron beam with an acceleration voltage of 15 kV or less, and the first element is at least one element selected from Ba, Sr, and Ca, The phosphor for a display device according to claim 1, wherein the second element is Y. A phosphor layer 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 layer with an electron beam having an acceleration voltage of 15 kV or less; A field emission display device comprising a source and an envelope for vacuum-sealing the phosphor layer;
A field emission display device, wherein the phosphor layer includes the phosphor for display device according to any one of claims 1 to 5.

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