JP2001167720A - Flat-panel display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-panel display which has a simple structure and can control the matrix display in a simple manner. SOLUTION: A display comprises a front glass 109; a glass substrate 101 disposed opposite to the front glass 109; a support structure consisting of a plurality of substrate-side ribs 104 disposed on the inner surface of the glass substrate 101 in a vertical direction with prescribed intervals, and a plurality of front face ribs 105 disposed on the inner surface of the front glass 109 in a vertical direction with prescribed intervals, the substrate-side ribs being orthogonal and in contact with the front ribs 105; a plurality of electron emission portions 120 pinched at regions between the substrate-side ribs 104; a plurality of light emitting portions disposed at regions between the front face ribs 105; and a plurality of electron draw-out electrodes 125 pinched at regions between the front face ribs 105 and supported by the substrate-side ribs 104, the electron draw-out electrodes 125 being opposite to, and spaced apart from the light emitting portions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display for emitting light by colliding electrons emitted from a field emission electron source with a phosphor, and more particularly to a flat panel display for performing dot matrix display.

[0002]

2. Description of the Related Art FED (Field Emission Display)
This is a flat panel (flat) display in which electrons emitted from an electron source arranged in a two-dimensional matrix collide with a light emitting portion formed of a phosphor formed on a counter electrode to emit light. This FED is a kind of vacuum microdevice using a micro vacuum tube of a submicron to micron size, that is, a field emission type cold cathode electron source. The basic configuration is the same triode as the conventional vacuum tube, but without using a hot cathode, a high electric field is concentrated on a sharp cathode (emitter) to extract electrons by quantum mechanical tunnel effect.

[0003] The extracted electrons are accelerated by the voltage between the anode and the cathode, and collide with and excite the phosphor film formed on the anode to emit light. The principle of excitation and emission of a phosphor by a cathode ray is the same as that of a cathode ray tube. In a general configuration of an FED, an electron-emitting portion and a light-emitting portion are formed between a evacuated front glass substrate and the substrate. In this case, an anode made of a transparent conductive material such as ITO is formed on the inner surface of the front glass substrate, and a light emitting part made of a phosphor is formed thereon.

Further, a cathode is formed on a substrate opposed to the substrate, and a cathode is formed thereon (Spindt type).
Micron-sized (1-2 μm) emitters are formed by partitioning them into insulating layers. Then, a gate electrode for extracting electrons from the emitter is formed on the insulating layer, and these constitute a minute electron emission portion. For example, about 200 electron-emitting portions are integrated in one pixel composed of red, blue, and green.

[0005] However, the conventional FED has a problem that it is very difficult to manufacture a large number of fine emitters over the entire display area because it must be formed uniformly. For example, in the case of a display having a diagonal length of about 10 inches, the number of pixels is about 800 × 600.
Therefore, in a conventional FED, as many as 200 × 800 × 600 = 96,000,000 fine emitters must be formed uniformly over the entire display area.
As the size of the display increases, the number must be increased, and there is a problem that it is difficult to increase the screen size of the FED using the conventional Spindt-type emitter.

In order to solve this problem, an FED using carbon nanotubes as a field emission type electron source instead of the Spindt type electron source has been proposed (JP-A-11-16).
2383). FED using this carbon nanotube
Is, as shown in FIG. 3, on the substrate 201, the electrode wiring layer 2
02 is formed, and the insulating film 20 is formed on the electrode wiring layer 202.
3 are formed. On the insulating film 203, substrate-side ribs 204 are arranged at predetermined intervals. On the insulating film 203 sandwiched between the substrate-side ribs 204, the electron emitting portions 205 are formed at predetermined intervals. The electron emission portion 205 is connected to one of the wirings of the electrode wiring layer 202 via a through hole formed in the insulating film 203. Further, as shown in FIG.
On the electrode 04, an electron extraction electrode 206 is formed.

Further, a transparent front glass substrate 207 is arranged to face the substrate 201, and
The substrate 201 and the substrate 201 are arranged at a predetermined distance from each other by a substrate-side rib 204 and a front rib 208 arranged orthogonally to the substrate-side rib 204. The space between the front glass substrate 207 and the substrate 201 is evacuated. The light emitting section 21 made of a phosphor is provided in a region between the front ribs 208 on the inner surface of the front glass substrate 207.
0 is formed in a stripe shape, and a metal back film 21 formed by evaporating an aluminum film on the surface thereof is formed.
1 is formed. As the phosphor constituting the light emitting unit 210, a phosphor that emits light by colliding electrons accelerated with high energy of 4 to 10 KeV, which is used for a CRT or the like, is used.

In the configuration described above, a negative potential is applied to a predetermined wiring of the electrode wiring layer 202 while a positive potential is applied to the metal back film 211 and a positive potential is applied to the electron extraction electrode 206. By applying a potential, electrons are emitted from the electron emitting portion 205 connected to the wiring. Then, the emitted electrons reach the light emitting unit 210 at a position facing the electron emitting unit 205, and the portion of the light emitting unit 210 emits light. Then, the light emitting units 21 arranged in a plurality of stripes
As shown in FIG. 3C, a plurality of electron-emitting portions 205 are arranged in a matrix so as to form a flat display.

[0009]

However, in the conventional flat panel display, it is necessary that the wiring of the electron extraction electrode and the wiring of the electrode wiring layer are orthogonal to each other in order to perform a matrix display. Therefore, an insulating layer is formed on the electrode wiring layer. The substrate-side rib is formed on the insulating layer at right angles to the wiring of the electrode wiring layer, and the electron extraction electrode is formed by printing on the substrate-side rib. For this reason, the structure is complicated, the number of manufacturing steps is large, and time is required for production. In addition, when sequentially scanning the electron extraction electrodes for performing the matrix display, it is necessary to individually switch the voltage of the two electron extraction electrodes sandwiching the electron emission portion, and the control is complicated. SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a flat display having a simple structure and easy control of matrix display.

[0010]

In order to solve the above-mentioned problems, a flat display according to the present invention includes a display surface having at least a part having a light-transmitting property, and a substrate opposed to the display surface and having an internal surface. A vacuum-evacuated envelope, and a plurality of substrate-side ribs vertically suspended at a predetermined interval from the substrate surface in the envelope to the display surface side in order to separate the display surface and the substrate at a predetermined interval. A support structure formed by contacting a plurality of front ribs vertically suspended from the display surface to the substrate side at a predetermined interval so as to be orthogonal to the substrate side ribs at the tops thereof, and sandwiched between the substrate side ribs on the substrate surface. A plurality of electron-emitting portions which are arranged in a predetermined region and to which a predetermined voltage is applied, a phosphor film which is arranged in a region sandwiched between front ribs of the display surface, and a predetermined portion which is arranged on the phosphor film and A plurality of light-emitting parts consisting of a metal film to which a voltage is applied and a front rib A plurality of electron extraction electrodes for extracting electrons from the electron emission section supported by the substrate-side ribs, the plurality of electron extraction electrodes being arranged in a separated area so as to be opposed to the light emitting section, and selected by the electron emission section and the electron extraction electrode. It is characterized by being configured to cause the phosphor film to emit light.

One example of the configuration of the electron emission portion of the above-described flat display is formed of carbon nanotubes formed of a cylindrical graphite layer. In this case, one configuration example of the carbon nanotube has a coaxial multilayer structure in which a plurality of graphite layers are stacked in a nested structure, and each graphite layer is closed in a cylindrical shape. One configuration example of the electron extraction electrode is formed of a metal plate having a plurality of electron passage portions. In addition, one configuration example of the plurality of light emitting units includes a red light emitting unit, a green light emitting unit, and a blue light emitting unit,
A predetermined number of these light emitting units are provided in this order.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a flat panel display according to the present invention. The configuration of the flat panel display will be described with reference to FIG.
The substrate-side ribs 104 are provided at predetermined intervals on the substrate 01, and a substrate electrode 121 is formed on a glass substrate 101 sandwiched between the substrate-side ribs 104, and an electron emission section 120 is formed on the substrate electrode 121. ing.

A transparent front glass 109 is disposed opposite to the glass substrate 101, and a front rib is provided on the surface of the front glass 109 facing the glass substrate 101 at a predetermined interval so as to be orthogonal to the substrate side rib 104. 105 is vertically provided and is in contact with the top of the substrate side rib 104. In a region sandwiched between the front ribs 105 of the windshield 109, a light emitting unit formed on the inner surface of the windshield 109,
An electron extraction electrode 125 is provided facing the light emitting portion and supported by the substrate-side rib 104.

The light emitting section is composed of a phosphor film formed on the inner surface of the front glass 109 and a metal back film 141 formed on the surface of the phosphor film. It has a red light emitting portion used, a green light emitting portion using a green light emitting phosphor 142G, and a blue light emitting portion using a blue light emitting phosphor 142B. The inner surface of the front glass 109 is repeatedly arranged a predetermined number of times in the order of the front rib 105, the red light emitting portion, the front rib 105, the green light emitting portion, the front rib 105, and the blue light emitting portion. 105 has a configuration.

The glass substrate 101 and the front glass 109 are opposed to each other via a frame-shaped spacer glass (not shown), and are bonded to the spacer glass with low-melting frit glass to form an envelope. The inside of the envelope is maintained at a degree of vacuum of the order of 10 ⁻⁵ Pa. Further, leads (not shown) for supplying an electric signal from the outside are connected to each of the substrate electrodes 121, each of the electron extraction electrodes 125, and each of the metal back films 141, and these leads are connected to the frit described above. It is vacuum sealed with glass.

Here, the glass substrate 10 constituting the envelope is
1. A low alkali soda glass is used for the front glass 109 and the spacer glass, and the glass substrate 101 and the front glass 109 use a plate glass having a thickness of 1 to 2 mm. The substrate electrode 121 is formed by screen-printing a conductive paste containing silver as a conductive material so as to have a thickness of about 10 μm on the glass substrate 101 in a predetermined pattern, and then firing the paste. In this case, the conductive material of the conductive paste is not limited to silver, for example, when the panel size is small and the electrical resistance does not matter,
Carbon may be used as the conductive material. Further, the substrate electrode 121 is not limited to the one formed by the above-described printing, and may be made of, for example, an aluminum thin film having a thickness of about 1 μm formed by using a well-known sputtering method and etching method.

The electron emission unit 120 screen-prints a bundle paste in which a bundle composed of a plurality of carbon nanotubes is collected in a conductive viscous solution in a predetermined pattern on the substrate electrode 121, and then fires the paste. And then irradiating the surface with laser, conductive particles on the surface,
The polyhedral particles of carbon in the binder and the bundle are removed by evaporation. The electron emitting portion 120 has a thickness of 20 to 100 μm, and as shown in FIG. 2A, a large number of carbon nanotubes are uniformly distributed on the surface of the bundle 123 exposed from the conductive film 122. Operates as an electron emission source.

As schematically shown in FIG. 2 (b), the carbon nanotube has a structure in which a single layer of graphite is closed in a cylindrical shape and a five-membered ring is formed at the tip of the cylinder. Since the typical diameter is as small as 10 to 50 nm, electrons can be field-emitted by applying an electric field of about 100 V. The carbon nanotube has a single-layer structure shown in FIG. 2B and a plurality of graphite layers stacked in a nested structure, and each graphite layer has a coaxial multilayer structure in which each graphite layer is closed in a cylindrical shape. However, either of them can be used as an electron emission source. The single-walled carbon nanotube is 1
Although an initial current of 00 μA is obtained with an applied voltage of 1.97 KV, observing the current value while keeping the voltage constant shows a temporal change in which the current value continuously decreases to several percent of the initial value.

On the other hand, a carbon nanotube having a coaxial multi-layer structure requires a voltage of 2.90 KV, which is higher than that of a carbon nanotube having a single-layer structure, to obtain an initial current of 100 μA, but the current value is reduced by several tens of percent from the initial value. After the initial decrease period, the constant value is maintained and stabilized. Also,
The carbon nanotube having the coaxial multilayer structure can be easily obtained by generating a DC arc discharge between the graphite electrodes, and thus has an advantage that it can be mass-produced at low cost. Therefore, in this embodiment, a carbon nanotube having a coaxial multilayer structure is used as the electron emission source. Note that the method of exposing the carbon nanotube is not limited to laser irradiation, and for example, selective dry etching using plasma may be used.

The substrate-side rib 104 is formed by repeatedly screen-printing an insulating paste containing frit glass having a low melting point on the glass substrate 101 so as to sandwich the electron-emitting portion 120 to a predetermined height, followed by firing. It is composed of an insulator. In this case, the substrate side rib 104 has a width of 50 μm.
m and height from the tip of carbon nanotube
Although the ribs were formed to be 0.6 mm and the rib spacing was set so that the width of the electron-emitting portion 120 sandwiched between the substrate-side ribs 104 was 2.54 mm, the present invention is not limited to this. The width of 104 is the width of the adjacent electron-emitting portion 120.
It is sufficient that insulation breakdown does not occur between them and the atmospheric pressure can be supported, and the height is desirably set low as long as no discharge occurs between the electron emitting portion 120 and the electron extraction electrode 125. Also, the rib spacing may be changed as needed.

The electron extraction electrode 125 has a thickness of 50 μm.
Stainless steel plate or 426 alloy,
A ladder-like structure having a rectangular electron passage portion 125a is formed by etching. In this case, the width of each electron extraction electrode 125 is set to be between the front ribs 105, and the crosspiece is set on the substrate-side rib 104 and on the center line of the substrate electrode 121. The electron passing unit 1
The shape of 25a is not limited to a rectangular shape, but may be another shape such as a mesh structure or a plurality of circular openings having a diameter of 20 to 100 μm.

The phosphor film is composed of a phosphor having a predetermined emission color. After the phosphor paste of each color is screen-printed on the inner surface of the front glass 109 in a stripe shape, it is baked to have a thickness of 10 to 100 μm. , With a width of 1 mm. In this case, each phosphor 142R, 142G, 142B used for red (R), green (G), and blue (B)
Are generally used in cathode ray tubes and the like.
Known oxide phosphors and sulfide phosphors that emit light by colliding electrons accelerated at a high voltage of KV are used. The metal back film 141 is formed of an aluminum thin film having a thickness of about 0.1 μm, and is formed on the surface of the phosphor film by using a well-known vapor deposition method.

The front rib 105 is made of an insulator formed by repeatedly screen-printing an insulating paste containing frit glass having a low melting point on a predetermined position on the inner surface of the front glass 109 until a predetermined height is reached, followed by firing. I have. In this case, the front rib 105 is formed so as to have a width of 150 μm and a height of 2.0 to 4.0 mm between the electron extraction electrode 125 and the metal back film 141.
The rib spacing is set so that the width of the light emitting portion sandwiched between the metal ribs 5 is 1 mm. However, the width of the front rib 105 is not limited to this. It is sufficient that the dielectric breakdown does not occur and the atmospheric pressure can be supported, and the height may be changed according to the voltage applied to the metal back film 141. Also, the rib spacing may be changed as needed.

Since the flat display of this embodiment is configured as described above, by providing a potential difference between the electron extraction electrode 125 and the substrate electrode 121 so that the electron extraction electrode 125 side has a positive potential, the electron difference is increased. The electric field concentrates on the carbon nanotubes of the electron emission portion 120 at the intersection of the extraction electrode 125 and the substrate electrode 121, and electrons are emitted from the tips of the carbon nanotubes where the electric field is high. For this reason, when a positive voltage (acceleration voltage) is applied to the metal back film 141, the electron emission portion 12
Electrons emitted from 0 are accelerated toward the metal back film 141, further penetrate the metal back film 141 and collide with the phosphor film, causing the phosphor film to emit light.

Therefore, for example, the electron extraction electrode 125
Are provided in the row direction in a predetermined number, the substrate electrodes 121 are provided in a predetermined number in the column direction, and a positive voltage (acceleration voltage) is applied to the metal back film 141.
Is applied, a predetermined positive voltage is applied to the electron extraction electrode 125 in the first row, and a predetermined negative voltage is applied to the substrate electrode 121 at an address to emit light from the first column to the predetermined column. By sequentially performing scanning in this manner and performing the scanning from the first row to the electron extraction electrodes 125 on the predetermined row, a dot matrix display can be performed. In this case, the substrate electrode 121 to which no voltage is applied and the electron extraction electrode 125
Is set to 0 V, or a negative bias voltage of about several tens of volts is applied to the electron extraction electrode 125 with respect to the substrate electrode 121 so that electrons are not emitted from the electron emission unit 120 other than the display address.

The voltage applied to the substrate electrode 121 is set to 0.
V and a positive voltage may be set to 0 V when light is emitted, and may be set to a positive voltage when light is not emitted. In this case, the electron extraction electrode 125 keeps the active row at a positive voltage and applies a negative bias voltage of about 0 V or several tens of volts to other rows to apply the negative bias voltage to the electron emission portions 120 other than the display address.
More electrons are not emitted. In this embodiment, the voltage applied to the metal back film 141 is 6K.
V, the voltage applied to the electron extraction electrode 125 is 500 V
And 0V, and the voltage applied to the substrate electrode 121 is 500V and 0V.
V. In this case, since a negative voltage is not used, a negative voltage power supply becomes unnecessary, and an effect of cost reduction can be obtained.

As described above, according to the flat panel display of this embodiment, the electron emitting portion 120 is constituted by the conductive film 122 containing carbon nanotubes formed by the printing method, and this is used as a field emission type cold cathode electron source. In this way, most of the components can be formed by a printing technique, so that they can be manufactured at very low cost. Also,
Since the electron emitting section 120 has a large number of carbon nanotubes arranged therein, the number of electron emitting sources per unit area is very large, and it is possible to emit more electrons. Brightness can be obtained.
Further, since the carbon nanotubes are chemically stable, the surface does not deteriorate due to the released gas, and there is no problem that the emission decreases after aging.

In order to separate the windshield 109 and the glass substrate 101 at a predetermined distance, a plurality of substrate side ribs vertically suspended at a predetermined distance from the surface of the glass substrate 101 in the envelope to the windshield 109 side. 104 and substrate side rib 1
Since a plurality of front ribs 105 which are provided at predetermined intervals from the inner surface on the side of the windshield 109 to the glass substrate 101 so as to be orthogonal to the surface 04 are brought into contact with each other at the tops, a support structure is formed. Since deformation can be prevented and the front glass 109 and the glass substrate 101 can be made thinner, there is an effect that the weight of the flat panel can be reduced.

Further, the front rib 105 is replaced with the substrate side rib 104.
And the electron extraction electrode 125
Is arranged in a region sandwiched between the front ribs 105 so as to face the light emitting portion and is supported by the substrate-side ribs 104.
Electrons are emitted only from the electron emitting portion 120 at the intersection of the electron extraction electrode 125 to which the positive voltage is applied and the substrate electrode 121 to which the negative voltage or 0 V is applied, and the opposing light emitting portion emits light. Dot matrix display is possible without arranging the sections 120 and the phosphor films in a dot shape.

Therefore, the substrate electrode 121 is disposed between the substrate-side ribs 104 suspended from the glass substrate 101, and the electron emission section 120 is provided on the substrate electrode 121. Can be reduced. Further, since the substrate electrode 121 and the electron emission portion 120 are arranged between the substrate-side ribs 104 suspended from the glass substrate 101, it is possible to prevent a leakage current between the adjacent substrate electrode 121 and the electron emission portion 120. it can. In addition, since each of the electron extraction electrodes 125 is partitioned by the front rib 105, discharge or short circuit between the adjacent electron extraction electrodes 125 can be prevented. Further, each light emitting unit is provided with a front rib 105.
, It is possible to prevent blurred light emission between adjacent R, G, and B.

[0031]

As described above, the flat panel display according to the present invention includes a display surface having at least a portion having a light-transmitting property, and a substrate opposed to the display surface, and an outer periphery of which is evacuated. In order to separate the display, the display surface and the substrate at a predetermined interval, a plurality of substrate-side ribs vertically suspended at a predetermined interval from the substrate surface in the envelope to the display surface side so as to be orthogonal to the substrate-side ribs. A support structure formed by contacting a plurality of front ribs vertically suspended at a predetermined interval from the display surface to the substrate side at the top of each other, and disposed in a region of the substrate surface interposed between the substrate side ribs. A plurality of electron-emitting portions to which a predetermined voltage is applied,
A plurality of light-emitting portions each including a phosphor film disposed in a region between the front ribs on the display surface and a metal film disposed on the phosphor film and to which a predetermined voltage is applied; A plurality of electron extraction electrodes for extracting electrons from the electron emission portion supported by the substrate-side ribs, the plurality of electron extraction electrodes being disposed opposite to the light-emitting portion in the region, and selectively provided by the electron emission portion and the electron extraction electrode. Since the phosphor film is configured to emit light, the structure of the substrate surface can be simplified and the number of manufacturing steps can be reduced. Further, when performing matrix display, it is only necessary to sequentially scan the electron extraction electrodes, so that an effect that control can be simplified can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial perspective sectional view showing an embodiment of the present invention.

FIG. 2 is a diagram illustrating details of an electron emission unit in FIG. 1;

FIG. 3 is a cross-sectional view and a plan view showing a configuration of a conventional flat display.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 101 ... Glass substrate, 104 ... Substrate side rib, 105 ... Front rib, 109 ... Front glass, 120 ... Electron emission part, 121 ... Substrate electrode, 122 ... Conductive film, 123 ... Bundle, 125 ... Electron extraction electrode, 125a ... Electron Passing portion, 141: metal back film, 142B: blue light emitting phosphor, 142G: green light emitting phosphor, 142R: red light emitting phosphor.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Nagamado 700, Wada, Ueno-cho, Ise, Mie Prefecture Inside Ise Electronics Industry Co., Ltd. (72) Inventor Junko Yoya 700, Wada, Ueno-cho, Ise, Mie Prefecture (72) Inventor Yahachi Saito 3012-3 Kawabe-cho, Tsu City, Mie Prefecture (72) Inventor Morio Yumura 1-1-1, Higashi 1-chome, Tsukuba City, Ibaraki Prefecture 5C031 DD17 5C032 CC10 CD04 5C036 EE01 EE14 EF01 EF06 EF09 EG01 EG12 EG15 EH06 EH08

Claims (5)

[Claims] An envelope that includes a display surface having at least a portion having a light-transmitting property and a substrate disposed to face the display surface and that is evacuated to the inside; In order to be spaced apart from each other, a plurality of substrate-side ribs vertically provided at predetermined intervals from the substrate surface in the envelope to the display surface side and the substrate from the display surface so as to be orthogonal to the substrate-side ribs. A supporting structure configured by contacting a plurality of front ribs vertically suspended at a predetermined interval on the side at the top of each other, and a predetermined voltage arranged in a region of the substrate surface interposed between the substrate side ribs and A plurality of electron-emitting portions to be applied, a phosphor film disposed in a region of the display surface interposed between the front ribs, and a metal film disposed on the phosphor film and applied with a predetermined voltage. A plurality of light emitting portions, and the light emitting portion in a region sandwiched between the front ribs And a plurality of electron extraction electrodes for extracting electrons from the electron emission portions supported by the substrate-side ribs, and selectively disposed by the electron emission portions and the electron extraction electrodes. A flat panel display configured to emit light from the phosphor film. 2. The flat panel display according to claim 1, wherein the electron-emitting portion is formed of carbon nanotubes formed of a cylindrical graphite layer. 3. The flat surface according to claim 2, wherein the carbon nanotube has a coaxial multilayer structure in which a plurality of graphite layers are stacked in a nested structure, and each graphite layer is closed in a cylindrical shape. display. 4. The flat display according to claim 1, wherein the electron extraction electrode is made of a metal plate having a plurality of electron passage portions. 5. The light emitting unit according to claim 1, wherein the plurality of light emitting units include a red light emitting unit, a green light emitting unit, and a blue light emitting unit, and a predetermined number of these light emitting units are provided in this order. 5. The flat panel display according to any one of 4.