JP2007329027A - Field emission display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a field emission display (FED) which is excellent in display characteristics such as a color reproductivity with a high luminance by forming a red light-emitting layer with a high luminance. <P>SOLUTION: The FED is provided with a phosphor layer formed inside a display panel, an electron emitting source to irradiate an electron beam of an accelerating voltage of 5 to 15kV on the phosphor layer and emit light and a peripheral unit to vacuum-seal the electron emitting source and the phosphor layer. The phosphor layer is composed of a layer mixed and made of a blue phosphor or a green phosphor which emits a blue light or a green light by being energized by the electron beam emitted from the electron emitting source and a red phosphor which emits a red light by being energized by the electron emitted form the electron emitting source and emits a red light by being energized by the blue light or the green light emitted from the blue phosphor or the green phosphor. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a field emission display device.

  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, the acceleration voltage (excitation voltage) of the electron beam is lower than that of a CRT. In addition, the current 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 leads to an increase in the amount of input charge per unit area for obtaining a predetermined luminance, and an increase in excitation energy density per unit pulse. It may become insufficient for a given value. For this reason, it has been difficult to obtain sufficient light emission luminance and lifetime when a phosphor based on zinc sulfide, which has been used for CRTs, is used. (For example, refer patent document 1) From such a background, the fluorescent substance for FEDs with high light-emission brightness is desired.

Conventionally, it is known that when irradiated with an electron beam having an excitation voltage of 5 kV or less, the europium-activated thiogallate phosphor represented by the chemical formula: SrGa ₂ S ₄ : Eu emits green light with a relatively high emission intensity. Yes. Further, this phosphor is known to be a phosphor that can be used because it has a good emission color, although the emission luminance does not reach that of the zinc sulfide phosphor for ordinary CRT.

On the other hand, as a red phosphor for FED, it is known that a yttrium oxysulfide phosphor exhibits a good light emission characteristic. However, when the excitation energy density per unit pulse increases, Since the emission efficiency is greatly reduced as compared with the phosphor, the emission luminance is not always sufficient. And as the red phosphor for FED, compounds having various chemical compositions have been studied, but phosphors having good emission color and high emission luminance have not been obtained yet.
JP 2002-226847 A

  The present invention has been made to solve such problems, and by forming a red light emitting layer having a high light emission luminance, a field emission display device (FED) having high luminance and excellent display characteristics such as color reproducibility. ).

  The field emission display device of the present invention includes a phosphor layer formed on an inner surface of a display panel, an electron emission source that emits light by irradiating the phosphor layer with an electron beam having an acceleration voltage of 5 to 15 kV, and the electron A field emission display device comprising: an emission source; and an envelope for vacuum-sealing the phosphor layer, wherein the phosphor layer is excited by an electron beam emitted from the electron emission source to emit blue light or A blue phosphor or a green phosphor emitting green light and a red light emitted from the blue phosphor or the green phosphor when excited by an electron beam emitted from the electron emission source and emitted from the blue phosphor or the green phosphor. And a red phosphor that emits red light when excited by the above-described structure.

  According to the field emission display device of the present invention, the phosphor together with a blue phosphor or a green phosphor emitting blue light or green light by excitation of a pulsed electron beam having an acceleration voltage of about 10 kV on the inner surface of the display panel. Since a layer in which a red phosphor emitting red light is emitted by excitation of blue light or green light emitted from is formed, red light emission with high light emission efficiency is obtained, and the luminance of red light emission is improved.

  In addition, the brightness lifetime of light-excited nitride-based red phosphors is not a problem, and the lifetime of blue or green phosphors directly excited by a pulsed electron beam is directly reflected in the lifetime of the phosphor. Therefore, the lifetime is considered to be worse than the conventionally known yttrium oxysulfide phosphor, but the lifetime balance with other colors is improved, and the color shift of white during electron beam irradiation is extremely reduced. There is an advantage. Therefore, a field emission display device having high luminance, good display characteristics, and a long lifetime can be realized.

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

  A field emission display (FED) according to an embodiment of the present invention includes a display panel (face plate) in which a phosphor layer is formed on a transparent substrate such as a glass substrate, and an acceleration voltage of 5 on the phosphor layer. Each has an electron emission source that emits light by irradiation with an electron beam of ˜15 kV.

  The phosphor layer is composed of a blue phosphor or a green phosphor that emits blue light or green light when excited by an electron beam emitted from an electron emission source (a blue phosphor layer or a green phosphor layer), an electron A layer comprising a red phosphor that emits red light when excited by an electron beam emitted from an emission source and emits red light when excited by blue or green light emitted from a blue phosphor or a green phosphor. Each has a red phosphor layer). In the embodiment, the blue phosphor layer or the green phosphor layer is laminated so as to be positioned closer to the electron emission source than the red phosphor layer.

  Examples of the blue phosphor or the green phosphor include silver (Ag) and aluminum (Al) activated zinc sulfide phosphor substantially represented by the chemical formula: ZnS: Ag, Al. It is also possible to use a multi-sulfide phosphor that combines europium (Eu) as an activator and a combination of an alkaline earth metal belonging to Group II of the periodic table and gallium (Ga) and sulfur (S). .

Examples of the multi-sulfide phosphor include Eu-activated strontium thiogallate phosphor substantially represented by the chemical formula: SrGa ₂ S ₄ : Eu, and Eu substantially represented by the chemical formula: BaGa ₂ S ₄ : Eu. An activated barium thiogallate phosphor can be mentioned respectively. The Eu-activated strontium thiogallate phosphor is excited by irradiation with a pulsed electron beam having an acceleration voltage of 5 to 15 kV, and emits green light having an emission peak in a wavelength region of 500 to 550 nm. The Eu-activated barium thiogallate (BaGa ₂ S ₄ : Eu) phosphor is excited by irradiation with a pulsed electron beam having an acceleration voltage of 5 to 15 kV, and has a blue-green color having an emission peak in a wavelength range of 480 to 520 nm. Alternatively, green light (hereinafter referred to as green light) is emitted.

In these multi-element sulfide phosphors, Eu is an activator that forms a luminescent center and has a high transition probability, so that high luminous efficiency can be obtained. Eu as an activator is contained in a range of 0.1 to 5.0 mol% with respect to strontium thiogallate (SrGa ₂ S ₄ ) or barium thiogallate (BaGa ₂ S ₄ ) which is a base material of the phosphor. It is preferred that A more preferable Eu content is 2.0 to 4.0 mol%. If the Eu content is out of this range, the emission luminance and emission chromaticity are lowered, which is not preferable.

Examples of the red phosphor include nitride phosphors each including an alkaline earth metal belonging to Group II of the periodic table and aluminum (Al) and silicon (Si). In particular, it is preferable to use a nitride phosphor activated with europium (Eu) substantially represented by the chemical formula: CaAlSiN ₃ : Eu. In this phosphor, Eu is an activator that forms an emission center, and has a high transition probability, so that the emission efficiency is high. Eu, which is an activator, is preferably contained in a range of 0.5 to 3.0 mol% with respect to calcium aluminum silicon nitride (CaAlSiN ₃ ) that is a base material of the phosphor. A more preferable Eu content is 1.5 to 3.0 mol%. If the content ratio of Eu is out of this range, the light emission luminance and light emission chromaticity are lowered, which is not preferable.

The CaAlSiN ₃ : Eu phosphor is excited by irradiation with a pulsed electron beam having an acceleration voltage of 5 to 15 kV to emit red light having a peak in a wavelength region of 630 to 670 nm, and the blue phosphor or green fluorescence described above. It is also excited by blue light or green light emitted from the body, and emits red light. That is, since this phosphor emits red light also by wavelength conversion (down-conversion) of blue light or green light emitted from the blue phosphor or green phosphor, red light with high luminance is emitted.

The multi-component sulfide phosphor that is the blue phosphor or the green phosphor used in the embodiment, and the CaAlSiN ₃ : Eu phosphor that is the red phosphor can be manufactured, for example, by the method described below.

That is, in the production of a multi-element sulfide phosphor, first, a phosphor raw material including an element constituting the phosphor base and an activator or a compound containing the element is obtained with a desired composition (SrGa ₂ S ₄ : Eu or BaGa ₂ S ₄ : Eu) and weigh them dry. Specifically, a predetermined amount of strontium sulfide or barium sulfide and gallium oxyhydroxide are mixed, and an appropriate amount of a compound containing an activator is added to obtain a phosphor material. Instead of strontium sulfide or barium sulfide, acidic strontium or acidic barium raw materials such as strontium sulfate or barium sulfate may be used. As an activator, europium sulfide or europium oxalate can be used.

  Next, such a phosphor raw material is filled in a heat-resistant container such as an alumina crucible or a quartz crucible together with appropriate amounts of sulfur and activated carbon. In addition and mixing of sulfur, it is preferable to mix a slightly larger amount than the phosphor raw material using a blender or the like, fill the mixed material in a heat-resistant container, and then cover the surface with sulfur. 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).

Firing conditions are important in controlling the crystal structure of the phosphor matrix, and a firing temperature of 700 to 900 ° C. is preferable. Although the firing time depends on the set firing temperature, it is preferably 60 to 180 minutes, and after firing, it is preferably cooled in the same atmosphere as firing. Thereafter, the obtained fired product is washed with ion-exchanged water or the like, dried, and then subjected to sieving to remove coarse particles as necessary, whereby Eu-activated strontium thiogallate phosphor (SrGa ₂ S). ₄ : Eu) or Eu-activated barium thiogallate phosphor (BaGa ₂ S ₄ : Eu) can be obtained.

  These phosphors can be synthesized using gallium metal and strontium sulfide or barium sulfide, or strontium sulfate or barium sulfate as starting materials. Firing can be performed under the firing conditions (temperature and time) described above.

The CaAlSiN ₃ : Eu phosphor, which is a red phosphor used in the embodiment, can be manufactured by, for example, the following method.

That is, a phosphor raw material including an element constituting the phosphor base and an activator or a compound containing the element is weighed so as to have a desired composition (CaAlSiN ₃ : Eu), and these are mixed in a dry manner. . Specifically, a predetermined amount of Ca ₃ N ₂ , AlN, and Si ₃ N ₄ are mixed, and an appropriate amount of a compound containing Eu as an activator is added to obtain a phosphor material.

Next, such a phosphor material is filled in a heat-resistant container such as an alumina crucible or a quartz crucible, and then fired in a reducing atmosphere (for example, an atmosphere of 3 to 5% hydrogen-remaining nitrogen). The firing temperature is preferably in the range of 1600-1800 ° C. Although the firing time depends on the set firing temperature, it is preferably 180 to 330 minutes, and after firing, it is preferably cooled in the same atmosphere as firing. Thereafter, the obtained fired product is washed with ion-exchanged water or the like, dried, and then subjected to sieving to remove coarse particles as necessary, whereby a CaAlSiN ₃ : Eu phosphor can be obtained.

  In the FED of the embodiment, an optical filter layer containing a red pigment is formed on a transparent substrate such as a glass substrate, and the red phosphor layer and the blue phosphor layer or the green phosphor layer are formed thereon. A red light emitting layer in which at least two of the body layers are laminated is formed. By providing an optical filter layer corresponding to the emission color of the phosphor, image characteristics such as color purity and contrast can be improved.

  Here, as the red pigment constituting the filter layer, either inorganic or organic pigments can be used. In particular, it is preferable to use a pigment that can be uniformly dispersed in the layer and can have sufficient transparency without causing light scattering. In addition, since the FED manufacturing process includes a high-temperature heating process, it is preferable to use a ferric oxide pigment that is an inorganic pigment. Formation of such a filter pattern made of a pigment is performed, for example, according to the following procedure. That is, firstly, a photoresist such as ammonium dichromate (ADC) / polyvinyl alcohol (PVA), sodium dichromate (SDC) / PVA, diazonium salt / PVA, etc. is mainly composed of pigment particles and a polymer electrolyte dispersant. The contained pigment dispersion is applied to the inner surface of the glass substrate by spin coating or the like and dried. Next, the pigment layer containing such a photoresist is exposed using a high-pressure mercury lamp or the like, the portion irradiated with ultraviolet rays is cured, and then developed using an alkaline aqueous solution, whereby a pigment having a predetermined pattern is obtained. Form a layer.

The red light emitting layer includes a red phosphor layer made of the CaAlSiN ₃ : Eu phosphor, which is the red phosphor, and a blue phosphor layer made of a blue phosphor or a green phosphor layer made of a green phosphor. It has a structure formed by laminating such that the layer or the green phosphor layer is on the red phosphor layer, that is, close to the electron emission source.

  The thicknesses of the red phosphor layer, the blue phosphor layer, and the green phosphor layer are each preferably 2 to 20 μm, and more preferably 2 to 10 μm. The reason why the thickness of these phosphor layers is limited to 2 μm or more is that it is difficult to form a phosphor layer in which phosphor particles are uniformly arranged with a thickness of less than 2 μm. On the other hand, when the thickness of each phosphor layer exceeds 20 μm, the light emission luminance is lowered and cannot be put to practical use. Furthermore, the total thickness of the red light emitting layer in which these two or more phosphor layers are laminated is preferably 10 to 30 μm, and more preferably 10 to 20 μm.

  The red light emitting layer can be formed by a known printing method or slurry method using the above-described red phosphor and blue phosphor or green phosphor.

In order to form a red light emitting layer by a printing method, first, a red phosphor, CaAlSiN ₃ : Eu phosphor, is mixed with a binder solution made of, for example, polyvinyl alcohol, n-butyl alcohol, ethylene glycol, water, etc. A phosphor paste is prepared, and this red phosphor paste is applied onto a glass substrate on which an optical filter layer is formed by a method such as screen printing. Next, a red phosphor layer made of CaAlSiN ₃ : Eu is formed, for example, by performing a baking process for decomposing and removing the binder component by heating at a temperature of 500 ° C. for 1 hour.

Next, Ag and Al-activated zinc sulfide phosphor (ZnS: Ag, Al), Eu-activated strontium thiogallate phosphor (SrGa ₂ S ₄ : Eu), or Eu is formed on the red phosphor layer thus formed. Blue fluorescence formed by mixing a blue phosphor such as an activated barium thiogallate phosphor (BaGa ₂ S ₄ : Eu) or a green phosphor with a binder solution composed of polyvinyl alcohol, n-butyl alcohol, ethylene glycol, water or the like. The green phosphor paste or the green phosphor paste is applied by a method such as screen printing, followed by baking at a temperature of, for example, 500 ° C. for 1 hour to decompose and remove the binder component. A phosphor layer is formed.

In the slurry method, a red phosphor slurry is prepared by mixing with a red phosphor CaAlSiN ₃ : Eu phosphor, pure water, polyvinyl alcohol, a photosensitive material such as ammonium dichromate, a surfactant, and the like. The phosphor slurry is applied and dried on a glass substrate on which an optical filter layer is formed using a spin coater or the like, and then exposed to ultraviolet light or the like, exposed and developed, and dried. Thus, after forming a red phosphor layer having a predetermined pattern, a blue phosphor layer or a green phosphor layer is formed thereon by a slurry method in the same manner as the red phosphor layer.

  In the red light emitting layer of this embodiment, red light is emitted from the red phosphor by excitation of a pulsed electron beam with an acceleration voltage of about 10 kV, and from the blue phosphor or green phosphor by excitation of the pulsed electron beam. The emitted blue light or green light is emitted to the red phosphor, and red light is emitted from the red phosphor also by excitation of this light. Therefore, light emission with high luminous efficiency is performed, and high-luminance red light emission is obtained.

  In addition, the lifetime of the brightness of red phosphors such as nitrides that are photoexcited hardly becomes a problem, and the lifetime of blue phosphors or green phosphors that are directly excited by a pulsed electron beam is the lifetime of phosphors. Since it is reflected as it is, there is an advantage that the color shift of white during electron beam irradiation becomes very small.

  An FED according to an embodiment of the present invention has a display panel in which the above-described red light emitting layer is formed on a transparent substrate such as a glass substrate as a face plate.

  FIG. 1 is a cross-sectional view showing a main configuration of an FED according to the first embodiment. In FIG. 1, reference numeral 1 denotes a face plate. The face plate 1 has a structure in which a phosphor layer 3 is formed on a transparent substrate such as a glass substrate 2. The phosphor layer 3 has a blue light-emitting layer made of a blue phosphor, a green light-emitting layer made of a green phosphor, and a red light-emitting layer having the above structure, and light made of a black conductive material between these light-emitting layers. The structure is separated by the absorption layer 4. As the blue phosphor and the green phosphor, known zinc sulfide phosphors can be used. The blue light-emitting layer, the green light-emitting layer, the red light-emitting layer, and the light absorption layer 4 that separates them are sequentially and repeatedly formed in the horizontal direction, and the portions where these phosphor layers 3 and light absorption layers 4 exist Is the image display area. Various patterns such as a dot shape or a stripe shape can be applied to the arrangement pattern of the light emitting layer and the light absorbing layer 4 of each color.

  As described above, the thickness of the entire red light emitting layer is preferably 10 to 30 μm (more preferably 10 to 20 μm), and a blue phosphor made of a blue phosphor so that no step is generated between the light emitting layers of the respective colors. The thickness of the light emitting layer and the green light emitting layer made of the green phosphor are preferably the same as those of the red light emitting layer.

  A metal back layer 5 is formed on the phosphor layer 3 including each of the blue light emitting layer, the green light emitting layer, and the red light emitting layer. 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, out of the 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 container (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. 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. An atmospheric pressure support member (spacer) 12 may be appropriately disposed between the face plate 1 and the rear plate 7 in order to prevent such deflection and to provide strength against atmospheric pressure.

  As described above, the FED of such an embodiment includes a red light emitting layer having a structure in which at least two layers of a red phosphor layer and a blue phosphor layer or a green phosphor layer are laminated. The luminance of red light emitted by irradiation with a pulsed electron beam having a voltage of 5 to 15 kV, more preferably 7 to 12 kV is high, and good display characteristics can be obtained.

  In the embodiment, the red light-emitting layer may be a layer in which the blue phosphor or the green phosphor and the red phosphor are uniformly mixed and dispersed. At this time, in order to obtain a bright red light emission, the particle diameter (average particle diameter) of the blue phosphor or the green phosphor particles that are excited by a pulsed electron beam with a low acceleration voltage to emit blue light or green light, The particle diameter (average particle diameter) of the red phosphor particles that emit red light by excitation of light from the blue phosphor or the green phosphor is set so that the latter average particle diameter is more than twice that of the former. It is necessary. The mixing ratio of the red phosphor and the blue phosphor or the green phosphor is preferably 6: 1 to 1: 1 by weight.

  Thus, the thickness of the entire red light emitting layer in which the blue phosphor or the green phosphor and the red phosphor are mixed and dispersed is preferably 15 to 30 μm, and more preferably 15 to 20 μm.

  Such a red light emitting layer can be formed by using the above-described printing method or slurry method using the mixture of the red phosphor and the blue phosphor or the green phosphor. Also in the FED of such an embodiment, the emission luminance of the red light emitting layer is high when irradiated with a pulsed electron beam having an acceleration voltage of 5 to 15 kV, more preferably 7 to 12 kV, and good display characteristics are obtained.

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

Examples 1-3
The raw material containing the element constituting the red phosphor matrix and the activator or a compound containing the element has a stoichiometric ratio of the composition shown in Table 1 (CaAlSiN ₃ : Eu, Eu content 2 mol%). The phosphor raw material obtained by weighing and mixing well was filled in a quartz crucible and fired in a reducing atmosphere. The firing conditions were 1800 ° C. × 300 minutes. Thereafter, the obtained fired product was washed with water, dried, and further sieved to obtain a europium (Eu) -activated nitride phosphor (CaAlSiN ₃ : Eu) as a red phosphor.

  In addition, raw materials including a blue or green phosphor matrix and an element constituting the activator or a compound containing the element are weighed so as to have a stoichiometric ratio indicating a composition as an excitation phosphor in Table 1. The phosphor raw material obtained by thoroughly mixing was filled in a quartz crucible and fired in a reducing atmosphere. Thereafter, the fired product obtained was washed with water, dried, and further sieved to obtain blue or green phosphors for excitation of red phosphors shown in Table 1.

Next, the Eu-activated nitride phosphor (CaAlSiN ₃ : Eu) obtained by the above method is used on a glass substrate on which an optical filter layer containing ferric oxide (Bengara) as a red pigment is formed. After forming a red phosphor layer having a thickness of 10 μm by screen printing, the blue or green phosphor was used on the red phosphor layer, and a blue or green phosphor layer having a thickness of 5 μm was formed by screen printing. Thus, a red light emitting layer was formed in which a red phosphor layer and a blue or green phosphor layer were sequentially laminated. Further, an aluminum metal back layer was formed on the red light emitting layer by a lacquer method.

As a comparative example, a red phosphor layer having a thickness of 10 μm was formed on a glass substrate by screen printing using Y ₂ O ₂ S: Eu which is a red phosphor. In the same manner as in No. 3, an aluminum metal back layer was formed by a lacquer method.

Next, the light emission luminance and the light emission chromaticity of the red light emitting layer and the red phosphor layer obtained in Examples 1 to 3 and the comparative example, respectively, were examined. The light emission luminance was measured by irradiating each light emitting layer with a pulsed electron beam having an acceleration voltage of 10 kV, a current density of 30 mA / cm ² and a pulse width of 15 μs. The emission luminance was determined as a relative value when the luminance of the red phosphor layer of the comparative example was 100.

  The emission chromaticity was measured using SR-3 manufactured by Topcon Corporation. 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 red light emitting layers obtained in Examples 1 to 3 each have a lower acceleration voltage (5 to 15 kV) and a higher current density than the red phosphor layers obtained in the comparative examples. It can be seen that the emission luminance when irradiated with a pulsed electron beam is greatly improved and has sufficiently good emission chromaticity.

Examples 4-8
In the same manner as in Examples 1 to 3, europium (Eu) activated nitride phosphor (CaAlSiN ₃ : Eu) (average particle size 10 μm), which is a red phosphor, and blue for exciting the red phosphor shown in Table 2 Alternatively, a green phosphor was obtained. The average particle diameter of the zinc sulfide phosphor (ZnS: Ag, Al), which is a blue or green phosphor for excitation, is 5 μm, and the average of the Eu-activated strontium thiogallate phosphor (SrGa ₂ S ₄ : Eu). The particle size was 2 μm.

  Next, on the glass substrate on which the optical filter layer containing ferric oxide (Bengara), which is a red pigment, is formed, the red phosphor and the blue phosphor or the green phosphor are mixed at the blending ratio shown in Table 2. A red light-emitting layer having a thickness of 15 μm was formed by screen printing using the mixed phosphor. Further, an aluminum metal back layer was formed on the red light emitting layer by a lacquer method.

  Next, the emission luminance and emission chromaticity of the red light emitting layers obtained in Examples 4 to 8 were examined in the same manner as in Examples 1 to 3. The emission luminance was determined as a relative value when the luminance of the red phosphor layer of the comparative example was 100. The measurement results are shown in Table 2.

  As is clear from Table 2, the red light emitting layers obtained in Examples 4 to 8 each have a lower acceleration voltage (5 to 15 kV) and a higher current density than the red phosphor layers obtained in the comparative examples. It can be seen that the emission luminance when irradiated with a pulsed electron beam is greatly improved and has sufficiently good emission chromaticity.

Examples 9-16
The glass substrate having the red light emitting layer obtained in each of Examples 1 to 8 was used as a face plate, and the face plate and a rear plate having a large number of electron-emitting devices were assembled through a support frame, and the gaps were formed. While evacuating, it was hermetically sealed to produce an FED. Thus, it was confirmed that the color reproducibility including light emission luminance was excellent, and good luminance characteristics were exhibited even after driving at room temperature and rated operation for 1000 hours.

  According to the FED of the present invention, red light emission with high luminance and good color purity can be obtained by irradiation with a pulsed electron beam having an acceleration voltage of 5 to 15 kV and a high current density, high luminance and color reproducibility, etc. Display with excellent display characteristics 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 (9)

A phosphor layer formed on the inner surface of the display panel, an electron emission source that emits light by irradiating the phosphor layer with an electron beam having an acceleration voltage of 5 to 15 kV, and the electron emission source and the phosphor layer are vacuum-sealed. A field emission display device comprising an envelope to be stopped,
The phosphor layer is
A blue phosphor or green phosphor that emits blue light or green light when excited by an electron beam emitted from the electron emission source, and a red phosphor that emits red light when excited by an electron beam emitted from the electron emission source A field emission display device comprising: a layer mixed with a red phosphor which emits red light when excited by blue light or green light emitted from the blue phosphor or green phosphor.   The phosphor layer includes a layer composed of the red phosphor (hereinafter referred to as a red phosphor layer), and a layer composed of the blue phosphor or the green phosphor (hereinafter referred to as a blue phosphor layer or a green phosphor layer). At least two layers have a layer formed so that the blue phosphor layer or the green phosphor layer is positioned closer to the electron emission source than the red phosphor layer. The field emission display device according to claim 1.   The phosphor layer has a layer in which the red phosphor and the blue phosphor or the green phosphor are mixed and dispersed, and the average particle size of the red phosphor is an average of the blue phosphor or the green phosphor. 2. The field emission display device according to claim 1, wherein the field emission display device has a particle size of 2 times or more.   The red phosphor is a nitride-based phosphor containing an alkaline earth metal belonging to Group II of the periodic table and aluminum (Al) and silicon (Si), respectively. 2. The field emission display device according to item 1. 5. The field emission display according to claim 4, wherein the red phosphor is a nitride phosphor activated by europium (Eu) substantially represented by a chemical formula: CaAlSiN ₃ : Eu.   The blue phosphor or the green phosphor is a zinc sulfide phosphor activated by silver (Ag) and aluminum (Al) substantially represented by the chemical formula: ZnS: Ag, Al. The field emission display device according to claim 1.   The blue phosphor or the green phosphor is a multi-component sulfide phosphor containing europium (Eu) as an activator and each containing an alkaline earth metal belonging to Group II of the periodic table and gallium (Ga) and sulfur (S). The field emission display device according to claim 1, wherein the field emission display device is a display device. 8. The blue phosphor or the green phosphor is a thiogallate phosphor activated by europium (Eu) substantially represented by a chemical formula: SrGa ₂ S ₄ : Eu. Field emission display. 8. The blue phosphor or the green phosphor is a thiogallate phosphor activated by europium (Eu) substantially represented by a chemical formula: BaGa ₂ S ₄ : Eu. Field emission display.

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