KR20070053483A - Red phosphor for electron emission display device and electron emission display device comprising the same - Google Patents

Abstract

The present invention relates to a red phosphor for an electron emission display device and an electron emission display device including the same, wherein the phosphor includes Y ₂ O ₃ : Eu and YVO ₄ : Eu. In addition, the electron emission display device of the present invention includes a first substrate and a second substrate disposed to face each other, an electron emission portion formed on the first substrate, and a driving electrode provided on the first substrate to control electron emission of the electron emission portion And fluorescent layers formed on one surface of the second substrate so that one color corresponds to each pixel region set on the first substrate, and the fluorescent layer is composed of a red fluorescent layer, a blue fluorescent layer, and a green fluorescent layer. The red fluorescent layer includes Y ₂ O ₃ : Eu and YVO ₄ : Eu.

The red phosphor of the present invention exhibits excellent luminance and color reproduction characteristics.

Electron emission display device, phosphor, luminance, color gamut, color coordinate

Description

RED PHOSPHOR FOR ELECTRON EMISSION DISPLAY DEVICE AND ELECTRON EMISSION DISPLAY DEVICE COMPRISING THE SAME}

1 is a partially exploded perspective view of an electron emission display device according to an exemplary embodiment of the present invention.

The present invention relates to a red phosphor for an electron emission display device and an electron emission display device including the same, and more particularly, to a red phosphor for an electron emission display device having improved luminance and color reproduction characteristics and an electron emission display device including the same. will be.

In general, the electron emission device may be classified into a method using a hot cathode and a method using a cold cathode according to the type of electron source.

Here, the cold-cathode electron emission device includes a field emitter array (FEA) type, a surface conduction emission type (SCE) type, a metal-insulating layer-metal type, and a metal-insulating layer type. Metal (MIM) type and Metal-Insulator-Semiconductor (MIS) type are known.

The MIM type and the MIS type electron emission device each have an electron emission portion formed of a metal / insulation layer / metal (MIM) and a metal / insulation layer / semiconductor (MIS) structure, and are disposed between two metals having an insulation layer therebetween, or When a voltage is applied between the metal and the semiconductor, a principle is used in which electrons move and accelerate from a metal having a high electron potential or from a semiconductor to a metal having a low electron potential.

The SCE type electron emission device forms an electron emission portion by forming a conductive thin film between a first electrode and a second electrode spaced apart from each other on a substrate and providing a micro crack in the conductive thin film, and applying a voltage to both electrodes. By using the principle that the electron is emitted from the electron emission portion when the current flows to the surface of the conductive thin film.

The FEA type electron emission device uses a principle that electrons are easily emitted by an electric field in vacuum when a material having a low work function or a large aspect ratio is used as the electron source, and molybdenum (Mo) or silicon (Si) is used. An example of forming an electron emitting portion using a tip structure having a sharp tip, which is mainly made of a material, or a carbon emitting substance such as carbon nanotubes has been developed.

As such, the electron emission device using the cold cathode basically includes an electron emission portion formed on the substrate and driving electrodes for controlling electron emission of the electron emission portion, and the on / off of electron emission for each pixel is caused by the action of the electron emission portion and the driving electrodes. Control off and electron emission.

The electron emission display device further includes a fluorescent layer on the electron emission device, and excites a fluorescent layer with electrons emitted from the electron emission unit to perform a predetermined display function. The fluorescent layer is a red, blue, or green fluorescent layer. It is composed.

An object of the present invention is to provide a red phosphor for an electron emission display device excellent in luminance and color reproduction characteristics.

It is still another object of the present invention to provide an electron emission display device including the red phosphor.

In order to achieve the above object, the present invention provides a red phosphor for an electron emission display device comprising Y ₂ O ₃ : Eu and YVO ₄ : Eu.

The invention also provides a first substrate and a second substrate disposed opposite to each other, an electron emission portion formed on the first substrate, drive electrodes provided on the first substrate to control electron emission of the electron emission portion, and a second And a red fluorescent layer, a green fluorescent layer, and a blue fluorescent layer disposed on one surface of the substrate and formed to correspond to one color for each pixel region set on the first substrate, wherein the red fluorescent layer includes Y ₂ O ₃ : Eu and YVO ₄ An electron emission display device comprising: Eu.

Hereinafter, the present invention will be described in more detail.

In the electron emission display device, electrons are emitted from an electron emission portion formed on the first substrate, and phosphors contained in the phosphor layer formed on the second substrate are blown by the emitted electrons, thereby being excited to implement an arbitrary color. Done. Therefore, the phosphor is required to have excellent color reproduction characteristics with high luminance.

The present invention relates to a red phosphor for an electron emission display device, comprising both Y ₂ O ₃ : Eu and YVO ₄ : Eu, which is capable of simultaneously obtaining satisfactory characteristics in luminance and color reproduction. It relates to a phosphor.

Conventionally, Y ₂ O ₂ S: Eu or Y ₂ O ₃ : Eu is mainly used as a red phosphor for an electron emission display device. However, Y ₂ O ₂ S: Eu has a low luminance and poor color reproduction characteristics, and Y ₂ O ₃ : Eu has a high luminance but low color reproduction rate.

Accordingly, in the present invention, by mixing Y ₂ O ₃ : Eu with good luminance and YVO ₄ : Eu with excellent color reproduction characteristics in an appropriate ratio, the color reproduction characteristics are improved while minimizing luminance degradation, thereby satisfying both luminance and color reproduction. A red phosphor having characteristics was created.

Y ₂ O ₃ : Eu efficiency (luminance per unit power) is 11.0 lumen / W, color coordinates are x = 0.629, y = 0.350 based on CIE coordinate system, and YVO ₄ : Eu efficiency is 6.1 lumen / W, color coordinate Are x = 0.677 and y = 0.327. By using Y ₂ O ₃ : Eu and YVO ₄ : Eu, satisfactory results were obtained in both luminance and color reproduction characteristics. For reference, the color reproducibility of the red phosphor may be determined by the x coordinate value of the CIE coordinate system. The larger the x coordinate value, the larger the color reproduction rate.

In the red phosphor of the present invention, Y ₂ O ₃ : Eu and YVO ₄ : Eu are preferably mixed at 10 to 150 parts by weight of YVO ₄ : Eu with respect to 100 parts by weight of Y ₂ O ₃ : Eu, and 25 to 100 More preferably, it is mixed in parts by weight, even more preferably in an amount of 33 to 67 parts by weight. When YVO ₄ : Eu is mixed at less than 10 parts by weight, the color reproducibility is lowered, and when mixed at an amount of more than 150 parts by weight, the luminance is lowered.

The present invention also provides an electron emission display device comprising the red phosphor of the present invention described above.

The electron emission display device of the present invention includes a first substrate and a second substrate disposed opposite to each other, an electron emission portion formed on the first substrate, drive electrodes provided on the first substrate to control electron emission of the electron emission portion; And a red fluorescent layer, a green fluorescent layer, and a blue fluorescent layer on one surface of the second substrate and formed to correspond to one color for each pixel region set on the first substrate, wherein the red fluorescent layer is Y ₂ O ₃ : Eu. And a red phosphor containing YVO ₄ : Eu.

In the red phosphor, Y ₂ O ₃ : Eu and YVO ₄ : Eu are preferably mixed in an amount of 10 to 150 parts by weight of YVO ₄ : Eu with respect to 100 parts by weight of Y ₂ O ₃ : Eu, and 25 to 100 parts by weight. More preferably mixed, even more preferably 33 to 67 parts by weight. When YVO ₄ : Eu is mixed at less than 10 parts by weight, the color reproducibility is lowered, and when it is mixed at more than 150 parts by weight, the luminance is lowered.

As the green phosphor, Y ₂ SiO ₅ : Tb, Y ₂ Si ₂ O ₇ : Tb, SrGa ₂ O ₄ : Eu, Gd ₂ O ₂ S: Tb, Y ₂ O ₂ S: Tb and mixtures thereof may be used. As the blue phosphor, Y ₂ SiO ₅ : Ce, SrGa ₂ S ₄ : Ce, Sr ₅ (PO ₄ ) Cl: Eu, and mixtures thereof may be used.

Formation of the fluorescent layer using the phosphors may be performed according to any process as long as it is a process used for forming a conventional fluorescent layer such as spin coating. The fluorescent layer forming process is made by preparing a fluorescent layer composition, the fluorescent layer composition may include a phosphor, a photosensitive monomer, a photoinitiator and a solvent.

Examples of the photosensitive monomer include ethylene glycol diacrylate, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, tetramethylolpropane tetraacrylate, tetramethylolpropane trimethacrylate, Pentaerythritol tetraacrylate or pentaerythritol tetramethacrylate can be preferably used.

The photoinitiator may be benzophenone, methyl o-benzoylbenzoate, 4,4-bis (dimethylamine) benzophenone, 4,4-bis (diethylamino) benzophenone, 2,2-diethoxyacetophenone, 2,2 -Dimethoxy-2-phenyl-2-phenylacetophenone, 2-methyl- [4- (methylthio) phenyl] -2-morpholinopropa-1-one, 2-benzyl-2-dimethylamino-1 -(4-morpholinophenyl) -1-butanone, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphineoxide or bis (2,4,6-trimethylbenzoyl) phenyl Phosphine oxides can be preferably used.

The solvent is ethyl carbitol, butyl carbitol, ethyl carbitol acetate, butyl carbitol acetate, texanol, terpin oil, dipropylene glycol methyl ether, dipropylene glycol ethyl ether, dipropylene glycol monomethyl ether acetate, γ- Butyrolactone, cellosolve acetate, butyl cellosolve acetate, tripropylene glycol can be preferably used.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention.

1 is a partially exploded perspective view of an electron emission display device according to an exemplary embodiment of the present invention.

Referring to the drawings, the electron emission display device includes a first substrate 2 and a second substrate 4 which are arranged in parallel to each other at predetermined intervals. Sealing members (not shown) are disposed at edges of the first substrate 2 and the second substrate 4 to bond the two substrates, and the first substrate 2, the second substrate 4, and the sealing member are vacuumed. Construct a container.

First, cathode electrodes 6, which are first electrodes, are formed on the first substrate 2 in a stripe pattern along one direction of the first substrate 2, and cover the cathode electrodes 6. 2) The first insulating layer 8 is formed in its entirety. Gate electrodes 10, which are second electrodes, are formed on the first insulating layer 8 in a stripe pattern along a direction orthogonal to the cathode electrode 6.

In the present exemplary embodiment, when the intersection region of the cathode electrode 6 and the gate electrode 10 is defined as a pixel region, at least one electron emission part 12 is formed in each pixel region over the cathode electrode 6, and the first insulation is formed. Openings 81 and 101 corresponding to the electron emission portions 12 are formed in the layer 8 and the gate electrode 10 to expose the electron emission portions 12 on the first substrate 2.

The electron emission unit 12 may be formed of materials emitting electrons when a electric field is applied in a vacuum, such as a carbon-based material or a nanometer-sized material. The electron emitter 12 may include, for example, carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbon, C60, silicon nanowires, and combinations thereof. Screen printing, direct growth, chemical vapor deposition or sputtering may be applied.

In the drawing, the electron emission part 12 and the gate electrode opening 101 have a circular shape and are arranged in a line along the length direction of the cathode electrode 6 in each pixel area. However, the planar shape of the electron emitter 12 and the gate electrode opening 101, the number and arrangement form per pixel area, etc. are not limited to the illustrated example and can be variously modified.

Meanwhile, the structure in which the gate electrode 10 is positioned above the cathode electrode 6 with the first insulating layer 8 interposed therebetween has been described, but the gate electrode 10 is disposed below the cathode electrode with the first insulating layer interposed therebetween. A structure located at is also possible. In this case, the electron emission part may be positioned in contact with the edge of the cathode electrode on the first insulating layer.

The focusing electrode 14, which is a third electrode, is positioned on the gate electrode 10 and the first insulating layer 8. A second insulating layer 16 is positioned below the focusing electrode 14 to insulate the gate electrode 10 and the focusing electrode 14, and to pass the electron beam through the second insulating layer 16 and the focusing electrode 14. Openings 161 and 141 are provided.

Next, on one surface of the second substrate 4 opposite to the first substrate 2, the fluorescent layer 18, for example, the red, green, and blue fluorescent layers 18R, 18G, and 18B may be randomly selected from each other. It is formed at intervals, and a black layer 20 for improving contrast of the screen is formed between each fluorescent layer 18.

The fluorescent layer 18 may be formed such that a fluorescent layer of one color corresponds to a pixel area set in the first substrate 2.

An anode electrode 22 made of a metal film such as aluminum is formed on the fluorescent layer 18 and the black layer 20. The anode 22 receives the high voltage necessary for accelerating the electron beam from the outside to maintain the fluorescent layer 18 in a high potential state, and visible light emitted toward the first substrate 2 of the visible light emitted from the fluorescent layer 18. Reflects the light toward the second substrate 4 to increase the brightness of the screen.

The anode electrode 22 may be formed of a transparent conductive film such as indium tin oxide (ITO) instead of a metal film. In this case, the anode electrode is positioned on one surface of the fluorescent layer 18 and the black layer 20 facing the second substrate 4, and may be formed in plural in a predetermined pattern. Moreover, the structure which forms simultaneously the above-mentioned transparent conductive film and a metal film as the anode electrode 22 is also possible.

Spacers 24 are disposed between the first substrate 2 and the second substrate 4 to support the compressive force applied to the vacuum container, and to maintain a constant gap between the two substrates 2 and 4. The spacers 24 are positioned corresponding to the black layer 20 so as not to invade the fluorescent layer 18.

The electron emission display device having the above-described configuration is driven by supplying a predetermined voltage to the cathode electrode 6, the gate electrode 10, the focusing electrode 14, and the anode electrode 22 from the outside. For example, one of the cathode electrode 6 and the gate electrode 10 receives a scan driving voltage to serve as a scan electrode, and the other electrode receives a data driving voltage to serve as a data electrode. The focusing electrode 14 receives a voltage required for electron beam focusing, for example, 0 V or a negative DC voltage of several to several tens of volts, and the anode electrode 22 requires a voltage for accelerating the electron beam, for example several hundreds to thousands of volts. A positive DC voltage is applied.

Then, an electric field is formed around the electron emission part 12 in the pixels in which the voltage difference between the cathode electrode 6 and the gate electrode 10 is greater than or equal to the threshold, and electrons are emitted therefrom. The emitted electrons are focused to the center of the electron beam bundle while passing through the focusing electrode opening 141, and are attracted by the high voltage applied to the anode electrode 22 to collide with the fluorescent layer 18 of the corresponding pixel to emit light.

In the above, the field emission array (FEA) type electron emission display device made of materials in which the electron emission portion emits electrons by an electric field in vacuum has been described. However, the present invention is not limited to the FEA type, but the electron emission portion and the focusing electrode. And other types of electron emission display devices having a fluorescent layer, of course.

Hereinafter, preferred examples and comparative examples of the present invention are described. However, the following examples are only preferred embodiments of the present invention and the present invention is not limited to the following examples.

 (Example)

Example 1-7

YVO ₄ : Eu was mixed in the amounts shown in Table 1 with respect to 100 parts by weight of Y ₂ O ₃ : Eu to prepare a red phosphor for an electron emission display device.

TABLE 1

Y ₂ O ₃ : YVO ₄ : Eu amount relative to 100 parts by weight of Eu Example 1 10 Example 2 25 Example 3 33 Example 4 43 Example 5 67 Example 6 100 Example 7 150

The efficiency and color coordinates of the red phosphors for the electron emission display devices of Examples 1 to 7 were measured by a cathode luminescense (CL) meter, and the measurement results are shown in Table 2 below.

TABLE 2

Efficiency (lumen / W) X-coordinate value of the CIE coordinate system Example 1 10.7 0.633 Example 2 10.0 0.637 Example 3 9.75 0.640 Example 4 9.5 0.643 Example 5 9.0 0.647 Example 6 8.5 0.650 Example 7 8.0 0.653

Through the measurement results of the efficiency and the x coordinate of the CIE coordinate system, it can be seen that the red phosphors of Examples 1 to 7 exhibit excellent characteristics in both luminance and color reproducibility.

As described above, the red phosphor for an electron emission display device according to the present invention is excellent in brightness and has an excellent color reproducibility.

Claims (7)

Red phosphor for an electron emission display device comprising Y ₂ O ₃ : Eu and YVO ₄ : Eu. The method of claim 1, Wherein the red phosphor comprises 10 to 150 parts by weight of YVO ₄ : Eu with respect to 100 parts by weight of Y ₂ O ₃ : Eu. The method of claim 2, Wherein the red phosphor comprises 25 to 100 parts by weight of YVO ₄ : Eu with respect to 100 parts by weight of Y ₂ O ₃ : Eu. The method of claim 3, wherein Wherein the red phosphor comprises 33 to 67 parts by weight of YVO ₄ : Eu with respect to 100 parts by weight of Y ₂ O ₃ : Eu. A first substrate and a second substrate disposed to face each other; An electron emission unit formed on the first substrate; Driving electrodes provided on the first substrate to control electron emission of the electron emission unit; And A red fluorescent layer, a green fluorescent layer, and a blue fluorescent layer disposed on one surface of the second substrate and formed to correspond to one color for each pixel region set in the first substrate, An electron emission display device according to any one of claims 1 to 4. The method of claim 5, The green fluorescent layer is a group consisting of Y ₂ SiO ₅ : Tb, Y ₂ Si ₂ O ₇ : Tb, SrGa ₂ O ₄ : Eu, Gd ₂ O ₂ S: Tb, Y ₂ O ₂ S: Tb and mixtures thereof An electron emission display device comprising one green phosphor selected from. The method of claim 6, The blue phosphor layer includes one red phosphor selected from the group consisting of Y ₂ SiO ₅ : Ce, SrGa ₂ S ₄ : Ce, Sr ₅ (PO ₄ ) Cl: Eu, and mixtures thereof. Display device.

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