TWI386966B - Field emission display - Google Patents

Description

Field emission display

The present invention relates to a field emission display, and more particularly to a large area planar field emission display.

Carbon Nanotube (CNT) is a new type of carbon material discovered by Japanese researcher Iijima in 1991. See "Helical Microtubules of Graphitic Carbon", S.Iijima, Nature, vol. 354, p56 (1991) . The carbon nanotubes have a very large aspect ratio (the length of which is above the order of micrometers and the diameter is only a few nanometers or tens of nanometers), have good electrical and thermal conductivity, and have good mechanical strength and good The chemical stability of these properties makes the carbon nanotubes an excellent field emission material. Therefore, the application of nano carbon tubes in field emission devices has become a research hotspot in the field of nanotechnology.

The field emission display is the next generation of emerging display with the most potential after the cathode ray tube (CRT) display, liquid crystal display and plasma display. Compared with other displays, field emission displays have higher contrast ratio, wider viewing angle, higher brightness, lower energy consumption, shorter response time and wider operating temperature, which are suitable for illumination sources. , flat panel display and full-color large screen display screen for outdoor use, and various advertising display panels.

The prior art provides a field emission display 100. Referring to FIG. 1 and FIG. 2 , the field emission display 100 includes a transparent substrate 110 , a plurality of support bodies 140 , an insulating substrate 130 , and the glass substrate 110 and the insulating substrate 130 . A plurality of supports 140 are spaced apart and vacuum-packed together. A surface of the glass substrate 110 facing the insulating substrate 130 is formed with a metal conductive layer 116, a phosphor powder layer 114, and a filter film 112. A plurality of row electrodes 134 and column electrodes 132 which are disposed to intersect each other are formed on the surface of the insulating substrate 130 facing the glass substrate 110. The plurality of row electrodes 134 and the plurality of column electrodes 132 are respectively disposed in parallel and equally spaced on the surface of the insulating substrate 130, and the insulating layer 136 is disposed at the intersection of the row electrode 134 and the column electrode 132. Each two adjacent row electrodes 134 and each two adjacent column electrodes 132 form a grid 138, and each grid 138 positions an electron-emitting unit 120. Each of the electron-emitting units 120 is composed of a cathode electrode 125, an anode electrode 126, and a cathode emitter 127 covering the cathode electrode 125 and the anode electrode 126. The cathode electrode 125 is electrically connected to the column electrode 132 corresponding to the cathode electrode 125, and the anode electrode 126 is electrically connected to the row electrode 134 corresponding to the anode electrode 126. An electron emission gap 124 is formed in the center of the cathode emitter 127. The cathode emitter 127 is a conductive film.

When the field emission display is in operation, the voltage between the cathode electrode 125 and the anode electrode 126 of the electron emission unit 120 is controlled by the column electrode 132 and the row electrode 134 electrically connected thereto, due to the two electrodes of the electron emission unit 120. The width of the electron emission gap 124 in the cathode emitter 127 is nanometer. Based on the principle of quantum tunneling, the electron emission gap 124 forms a tunnel current under the voltage between the cathode electrode 125 and the anode electrode 126 (see , Surface conduction electron emission display technology advances, liquid crystal and display, V21, P226-231 (2006)). A high voltage is applied to the metal conductive layer 116 on the surface of the glass substrate 110, so that a strong electric field is formed between the metal conductive layer 116 and the insulating substrate 130. The electrons are bombarded onto the phosphor layer 114 on the surface of the glass substrate 110 by the strong electric field, thereby realizing light-emitting display.

The above field emission display 100 has the following disadvantages: First, the width of the emission gap 124 of the cathode emitter 127 is very small, resulting in a large current intensity of the tunnel current formed, so that the field emission display consumes a large amount of energy. Second, the phosphor layer 114 of the field emission display is disposed on the surface of the glass substrate 110. Since the current intensity of the tunnel current in the emission gap 124 is large, the electron conduction layer 116 of the electrons in the tunnel current on the surface of the transparent substrate 110 Under the action of the electric field between the insulating substrate 130, only a small amount of electrons are bombarded onto the phosphor layer 114 of the transparent substrate 110, resulting in low luminous efficiency of the phosphor layer 114. Third, due to limitations in the fabrication process, in the large-area field emission electronic device 100 fabricated using the conductive film containing the metal compound as the cathode emitter 127, the size and position of the respective electron emission gaps 124 are different, resulting in a field emission display. The overall uniformity of the electron emission is poor.

In view of this, it is necessary to provide a large-area field emission display with low energy consumption, high luminous efficiency of the phosphor powder layer, and stable electron emission performance.

A field emission display comprising: a transparent substrate; a plurality of supporting bodies; an insulating substrate disposed opposite to the transparent substrate by a plurality of supporting bodies; a plurality of row electrodes and column electrodes are respectively disposed in parallel and equally spaced on the insulating substrate The plurality of row electrodes and the plurality of column electrodes are disposed to intersect each other, and each two adjacent row electrodes and each two adjacent column electrodes intersect to form a grid, and the row electrodes and the column electrodes are electrically insulated; Pixel unit, each pixel unit corresponding to a grid setting, each image The element unit comprises a phosphor layer, an anode electrode and a cathode electrode, and a cathode emitter, wherein the anode electrode and the cathode electrode are respectively electrically connected to the corresponding row electrode and the column electrode, and the cathode emitter has one end and corresponding The cathode electrode is electrically connected; wherein the phosphor powder layer is disposed on a surface of the corresponding anode electrode.

Compared with the prior art, the field emission display has a phosphor powder layer disposed on the surface of the anode electrode, and the anode electrode and the cathode electrode are spaced apart from the surface of the insulating substrate, so that most of the electrons emitted by the cathode emitter are bombarded to the anode surface. The phosphor layer is on the layer, thereby greatly improving the luminous efficiency of the phosphor layer.

The field emission display of the present technical solution will be described in detail below with reference to the accompanying drawings.

Referring to FIG. 3 and FIG. 4 , an embodiment of the present disclosure provides a field emission display 200 including: a transparent substrate 210; a plurality of supporting bodies 240; an insulating substrate 230 passing through the plurality of supporting bodies 240 and the transparent substrate 210 The plurality of pixel units 220 are disposed on the insulating substrate 230; and the plurality of row electrodes 234 and the plurality of column electrodes 232 are disposed on the surface of the insulating substrate 230 facing the transparent substrate 210. The plurality of row electrodes 234 are parallel to each other and the interval between each two adjacent row electrodes 234 is equal. The plurality of column electrodes 232 are parallel to each other and the interval between each two adjacent column electrodes 232 is equal. The electrode 234 is separated from the column electrode 232 by an insulating layer 236 to prevent short circuit. Each two adjacent row electrodes 234 and each two adjacent column electrodes 232 form a grid structure 238, and each grid structure 238 positions one pixel unit 220.

The plurality of pixel units 220 are correspondingly disposed in the grid structure 238, and each of the grid structures 238 is provided with a pixel unit 220, and the plurality of pixel units 220 form a display matrix on the insulating substrate. Each pixel unit 220 includes an anode electrode 226 and a phosphor layer 228, a cathode electrode 225, and a cathode emitter 227. The anode electrode 226 is corresponding to and spaced apart from the cathode electrode 225, and the anode electrode 226 and the cathode electrode 225 are electrically connected to the row electrode 234 and the column electrode 232, respectively. The phosphor layer 228 covers the surface of the corresponding anode electrode 226. The cathode emitter 227 is disposed between the anode electrode 226 and the cathode electrode 225, and one end of the cathode emitter 227 is electrically connected to the cathode electrode 225, and the other end is directed to the corresponding anode electrode 226. The cathode emitter 227 is spaced apart from or disposed on the insulating substrate 230. In order to obtain more uniform electron emission performance, in the embodiment, the anode electrode 226 in the pixel unit 220 of the same row is electrically connected to the same row electrode 234, and the cathode electrode 225 and the same column electrode 232 in the pixel unit 220 of the same column are electrically connected. connection.

The transparent substrate 210 is made of a transparent material such as glass or the like and is formed into a flat plate shape. The size and thickness of the transparent substrate 210 are not limited, and those skilled in the art can select as needed.

The support body 240 is a rectangular parallelepiped insulating material such as plastic, glass, ceramic, or the like. The thickness of the support body 240 should be greater than the thickness of the row electrode 234 and the column electrode 232. When the area of the transparent glass substrate 210 is increased, a plurality of support bodies 240 may be disposed on the insulating substrate 230 at equal intervals. In this embodiment, the support body 240 preferably has a thickness of 10 micrometers to 2 millimeters and a width of 30 micrometers to 100 micrometers.

The insulating substrate 230 is an insulating substrate, such as a glass substrate, and a plastic base. Board and so on. The size and thickness of the insulating substrate 230 are not limited, and those skilled in the art can select according to actual needs. In this embodiment, the insulating substrate 230 is preferably a glass substrate having a thickness of more than 1 mm and a side length of more than 1 cm.

The plurality of row electrodes 234 and the plurality of column electrodes 232 are an electrical conductor such as a metal layer or the like. In this embodiment, the plurality of row electrodes 234 and the plurality of column electrodes 232 are preferably planar conductors printed with a conductive paste, and the row spacing and the column spacing of the plurality of row electrodes 234 and the plurality of column electrodes 232 are 300. Micron ~ 500 microns. The row electrode 234 and the column electrode 232 have a width of 30 micrometers to 100 micrometers and a thickness of 10 micrometers to 50 micrometers. In this embodiment, the intersection angle of the row electrode 234 and the column electrode 232 is 10 degrees to 90 degrees, preferably 90 degrees. In this embodiment, the row electrode 234 and the column electrode 232 are prepared by printing a conductive paste on the insulating substrate 230 by a screen printing method. The composition of the conductive paste includes metal powder, low melting point glass powder, and a binder. Among them, the metal powder is preferably silver powder, and the binder is preferably terpineol or ethyl cellulose. In the conductive paste, the weight ratio of the metal powder is 50 to 90%, the weight ratio of the low melting point glass powder is 2 to 10%, and the weight ratio of the binder is 10 to 40%.

The cathode electrode 225 and the anode electrode 226 are an electric conductor such as a metal layer or the like. In this embodiment, the cathode electrode 225 and the anode electrode 226 are a planar conductor, and the size thereof is determined according to the size of the grid 238. The cathode electrode 225 and the anode electrode 226 are directly connected to the above-described column electrode 232 and row electrode 234, thereby achieving electrical connection. The cathode electrode 225 and the anode electrode 226 have a length of 10 μm to 1 mm, a width of 1 μm to 100 μm, and a thickness of 1 μm to 100 μm. In this embodiment, the cathode electrode 225 and the anode electrode The length of 226 is preferably 150 microns, the width is preferably 50 microns, and the thickness is preferably 50 microns. In this embodiment, the material of the cathode electrode 225 and the anode electrode 226 is a conductive paste, which is printed on the insulating substrate 230 by screen printing. The composition of the conductive paste is the same as that of the conductive paste used for the electrode lead described above.

The phosphor layer 228 is disposed on the surface of the corresponding anode electrode 226. The material of the phosphor layer 228 includes high pressure phosphor powder and low pressure phosphor powder. The phosphor layer 228 may be disposed on the surface of the anode electrode 226 by a deposition method or a coating method. The phosphor layer 228 has a thickness of 5 microns to 50 microns.

The cathode emitter 227 includes an electron emitter 223 or a plurality of parallel and equally spaced electron emitters 223, such as a twisted wire, a single carbon fiber or a long carbon nanotube wire. The electrical connection between one end of the cathode emitter 227 and the cathode electrode 225 may be electrically connected through a conductive paste, or may be achieved by intermolecular force or other means. Each of the electron emitters 223 includes an electron emission end 229 which is an end of the electron emitter 223 away from the cathode electrode 225. The distance between the electron-emitting end 229 and the anode electrode 226 is from 1 micrometer to 200 micrometers. The length of the electron emitter 223 is 200 micrometers to 400 micrometers, and the spacing between adjacent electron emitters 223 is 1 nanometer to 100 nanometers. Referring to FIG. 3, in the present embodiment, the cathode emitter 227 includes a plurality of long-line carbon nanotube long lines arranged in parallel, and each nanocarbon tube long line is an electron emitter 223. When a plurality of parallel arranged carbon nanotube long wires are used as the cathode emitter 227, one end of each nanocarbon long line is electrically connected to the cathode electrode 225, and the other end is directed to the anode electrode 226 as an electron-emitting end of the electron emitter 223. 229. The distance between the electron emission end 229 and the anode electrode 226 is 1 micrometer. ~100 microns. The length of the long carbon nanotubes is 200 micrometers to 300 micrometers, and the spacing between adjacent nanocarbon tubes is 1 nanometer to 50 nanometers. The carbon nanotube long line includes a plurality of carbon nanotube bundles arranged end to end and arranged in a preferred orientation, and adjacent carbon nanotube bundles are connected by van der Waals force. The carbon nanotube bundle includes a plurality of parallel and closely arranged carbon nanotubes. The carbon nanotubes in the long line of the carbon nanotubes are single-walled, double-walled or multi-walled carbon nanotubes. The carbon nanotubes have a length ranging from 10 micrometers to 100 micrometers, and the carbon nanotubes have a diameter of less than 15 nanometers. The electron emitter 223 in the cathode emitter 227 has a good electron emission characteristic because of its large aspect ratio, so that the emission efficiency of the cathode emitter 227 is high.

The pixel unit 220 may further include a fixed electrode 221 disposed on the corresponding cathode electrode 225, and configured to fix the cathode emitter 227 on the cathode electrode 225, and the fixed electrode 221 It is an optional part. In this embodiment, the material of the fixed electrode 221 is the same as the material of the anode electrode 226, and the fixed electrode 221 can be disposed on the corresponding cathode electrode 225 by screen printing, thereby fixing the cathode emitter 227 to the cathode electrode 227. Above the cathode electrode 225.

When the large-area field emission display 200 of the embodiment is in operation, the scan electrode and the signal electrode of the driving circuit are respectively connected to the row electrode 234 and the column electrode 232 on the insulating substrate 230, and when the scan electrode and the signal electrode are simultaneously turned on. A potential difference will be formed between the cathode electrode 225 and the anode electrode 226 in the corresponding pixel unit 220, so that electrons are emitted from the electron-emitting end 229 of the cathode emitter 227 electrically connected to the cathode electrode 225 and bombarded onto the surface of the anode electrode 226. Phosphor layer 228, due to the cathode The electron-emitting end 229 of the emitter 227 is spaced apart from the anode electrode 226 and directed toward the anode electrode 226, so that most of the electrons are accurately bombarded onto the phosphor layer 228, thereby greatly improving the luminous efficiency of the phosphor layer. In the large-area field emission display 200 of the present embodiment, the row spacing and the column spacing between the plurality of cathode emitters 227 are equal, and the interval between the end of each cathode emitter 227 away from the cathode electrode 255 and the anode electrode 256 is equal. Each of the cathode emitters 227 includes a plurality of electron emitters 223 arranged in parallel and at equal intervals, so that the emitted electrons have good overall uniformity. In addition, in the large-area field emission display 200, at the same driving voltage, the electron-emitting end 229 of the cathode emitter 227 and the anode electrode 226 have a larger interval, so that the current intensity of the emission current is smaller, thereby making the large area Field emission display 200 consumes less power.

In addition, those skilled in the art can make other changes in the spirit of the present invention. Of course, these modifications in accordance with the spirit of the present invention should be included in the scope of the present invention.

100,200‧‧‧ field emission display

110,210‧‧‧ Transparent substrate

114,228‧‧‧Fluorescent powder layer

120‧‧‧Electronic emission unit

124‧‧‧Electronic emission gap

125,225‧‧‧cathode electrode

126,226‧‧‧Anode electrode

127,227‧‧‧ cathode emitter

130,230‧‧‧Insulation base

132,232‧‧‧ column electrodes

134,234‧‧‧ rows of electrodes

136,236‧‧‧Insulation

138, 238‧‧ Grid

140,240‧‧‧Support

220‧‧‧pixel unit

221‧‧‧Fixed electrode

223‧‧‧Electronic emitters

229‧‧‧Electronic emission tip

1 is a side view of a field emission display of the prior art.

2 is a top plan view of a field emission display of the prior art.

3 is a top plan view of a field emission display of an embodiment of the present technology.

4 is a side view of a field emission display of an embodiment of the present technology.

210‧‧‧Transparent substrate

220‧‧‧pixel unit

221‧‧‧Fixed electrode

225‧‧‧Cathode electrode

226‧‧‧Anode electrode

227‧‧‧ cathode emitter

229‧‧‧Electronic transmitter

230‧‧‧Insulation base

240‧‧‧Support

Claims (13)

A field emission display comprising: a transparent substrate; a plurality of supporting bodies; an insulating substrate disposed opposite to the transparent substrate by the plurality of supporting bodies; a plurality of row electrodes and column electrodes are respectively disposed in parallel and equally spaced from the insulating layer On the substrate, the plurality of row electrodes are disposed across the plurality of column electrodes, and each two adjacent row electrodes and each two adjacent column electrodes intersect to form a grid, and the row electrodes and the column electrodes are electrically insulated; a pixel unit, each pixel unit corresponding to a grid arrangement, each pixel unit includes a phosphor layer, an anode electrode and a cathode electrode are spaced apart from the insulating substrate, and a cathode emitter, the anode electrode and The cathode electrodes are electrically connected to the respective row electrodes and the column electrodes, and one end of the cathode emitter is electrically connected to the corresponding cathode electrode; and the improvement is that the phosphor powder layer is disposed on the surface of the corresponding anode electrode. The field emission display of claim 1, wherein the other end of the cathode emitter is spaced apart from the corresponding anode electrode and directed to the anode electrode, and the other end of the cathode emitter and the anode electrode are The spacing between 1 micron and 200 micron is used. The field emission display of claim 1, wherein the cathode emitter is spaced apart from or disposed on the insulating substrate, and the cathode emitter comprises an electron emitter or a plurality of parallel and equally spaced Arranged electron emitters. The field emission display of claim 3, wherein the The spacing between the electron emitters is from 1 nm to 100 nm. The field emission display of claim 3, wherein the electron emitter comprises a twisted wire, a single carbon fiber or a carbon nanotube long wire. The field emission display of claim 5, wherein the long carbon nanotube line comprises a plurality of carbon nanotube bundles arranged end to end and arranged in a preferred orientation, and the adjacent carbon nanotube bundles pass through the van der Waals Valli connection. The field emission display of claim 6, wherein the carbon nanotube bundle comprises a plurality of parallel and closely arranged carbon nanotubes. The field emission display of claim 7, wherein the carbon nanotubes are single-walled carbon nanotubes, double-walled carbon nanotubes or multi-walled carbon nanotubes. The field emission display of claim 8, wherein the carbon nanotubes have a length of 10 micrometers to 100 micrometers and a diameter of less than 15 nanometers. The field emission display of claim 1, wherein an insulating layer is disposed at an intersection of the row electrode and the column electrode. The field emission display of claim 1, wherein the plurality of pixel units are arranged in an array corresponding to the grid, and the anode electrodes of the pixel units disposed in the same row are electrically connected to the same row electrode, and are disposed on The cathode electrodes of the pixel units of the same column are electrically connected to the same column electrode. The field emission display of claim 1, wherein the pixel unit further comprises a fixed electrode disposed on the corresponding cathode electrode. The field emission display of claim 1, wherein the material of the phosphor layer is low pressure phosphor powder or high pressure phosphor powder, and has a thickness of 5 micrometers to 50 micrometers.