TWI394195B - Field emission pixel tube - Google Patents

Description

Field emission pixel tube

The present invention relates to a field emission element, and more particularly to a field emission pixel tube.

The field emission electron source and the field emission illuminating technology that emits light by bombarding the fluorescent substance with the electron source have been applied in the field of field emission flat panel display. This field emission technique is based on a vacuum environment that uses an applied electric field to excite the electrons at the tip. In the conventional field emission electron source, a fine tip such as a molybdenum tip and a tantalum tip are generally used as an electron-emitting end. With the development of nanotechnology, a carbon nanotube is also used as an electron-emitting end.

The CNT yarn has excellent field emission performance and a large emission current at a lower anode voltage. However, this advantage is disadvantageous in field emission pixel tubes. Because the field emission pixel tube works by electron bombardment of fluorescent powder, the optimal working condition of the fluorescent powder is high voltage and small current. Working under conditions of low voltage and high current will seriously reduce the luminous efficiency and life of the fluorescent powder.

In view of this, it is necessary to provide a nano-carbon pipeline field emission pixel tube that can operate under high voltage and low current conditions.

A nanocarbon pipeline field emission pixel tube that can operate under high voltage and low current conditions will be described below by way of example.

A field emission pixel tube comprising a housing, an anode and a cathode respectively disposed at two ends of the housing, The cathode includes a nanocarbon pipeline, and the field emission pixel tube further includes a shield electrode disposed around the nanocarbon pipeline.

When the field emission pixel tube is in operation, the cathode and the shield electrode are connected to a low potential, and the anode is connected to a high potential. Since the shield can shield the high voltage of the anode, it can significantly reduce the electric field strength on the surface of the nanocarbon pipeline. The smaller the diameter of the field emission pixel tube, the more obvious the shielding effect. Due to the low electric field strength of the surface of the nanocarbon pipeline, its emission current is reduced, but its operating voltage is high. It meets the ideal working conditions of the field emission pixel tube and has good emission effect and long service life.

11‧‧‧ cathode

12‧‧‧Anode

13‧‧‧Fluorescent layer

14,24‧‧‧Shielding pole

10,20‧‧‧shell

100‧‧ ‧ field emission pixel tube

102‧‧‧Lighting Department

111‧‧‧Support

1 is a cross-sectional view showing the structure of a field emission pixel tube of the first embodiment.

2 is a cross-sectional view showing the structure of a field emission pixel tube of the second embodiment.

Referring to FIG. 1, the field emission pixel tube 100 of the first embodiment includes a housing 10, a cathode 11, an anode 12, a phosphor layer 13, and a shield electrode 14.

The housing 10 has a light exit portion 102. The housing 10 is made of an insulating material such as quartz, glass, ceramic, plastic, or the like. It may be a hollow cylinder, a rectangular parallelepiped, a cube, a polygonal prism, or the like. The light exit surface of the light exiting portion 102 may be a flat surface or a curved surface that diverges or converges on the light. The inside of the casing 10 is evacuated. Preferably, in order to maintain the degree of vacuum in the casing 10, a getter (not shown), such as an evapotranspiration getter metal film, may be added to the casing 10. The getter may be formed on the inner wall of the casing 10 by vapor deposition before the casing is sealed.

The cathode 11 and the anode 12 are located in the casing 10 and are oppositely disposed at opposite ends of the casing 10. The anode is disposed adjacent to one end of the light exit portion 102 of the housing 10. The cathode 11 includes a support body 111 and a nano carbon line 112 disposed on the support body 111. The support body 111 has one end located inside the housing 10 and the other end extending outside the housing 10 for connecting a power source (not shown). The nano carbon line 112 is disposed on the support body 111 On one end of the housing. The support body 112 is a conductive material, and the support body 111 provides support for the nanocarbon line 112 and electrically connects the nanocarbon line 112 to the power source.

The nano carbon line 112 may include a plurality of carbon nanotubes that are substantially parallel to each other, and the carbon nanotubes may be single-walled carbon nanotubes or multi-walled carbon nanotubes. Of course, a carbon nanotube glue line structure can also be used. The multiple carbon nanotubes are connected by van der Waals force. The nanocarbon line 112 can have a length of from 0.1 mm to 10 mm and a diameter of from 1 micron to 1 mm. The nano carbon line 112 may be bonded to the support 111 by a conductive paste such as silver paste, or the nanocarbon line 112 may be welded to the support 111. Before the nanocarbon line 112 is connected to the support 111, the nanocarbon line 112 can be immersed in a solvent such as ethanol, and then subjected to heat treatment in a vacuum to volatilize the solvent. The conductivity and mechanical strength of the nanocarbon line 112 thus treated are enhanced.

The anode 12 may be a transparent conductive film such as an indium tin oxide film or an electron-transmissive conductive film such as an aluminum film. When the anode 12 is a transparent conductive film, the phosphor layer 13 may be disposed on one side of the anode 12 facing the cathode 11. When the anode 12 is made of an electron-transmissive conductive film, the phosphor layer 13 may be disposed on the inner wall of the casing 10 or on the side of the anode 12 facing away from the cathode 11, and may be filled in the anode 12 and the casing 10. between. In the present embodiment, the anode 12 is an aluminum film, and the phosphor layer 13 is disposed on the side of the anode 12 facing away from the cathode 11. The fluorescent layer can be white fluorescent powder or color fluorescent powder such as red fluorescent powder, blue fluorescent powder or green fluorescent powder.

In the present embodiment, the shield electrode 14 is a ring-shaped electrode that can be bonded to the outer wall of the casing 10 and disposed around the flight path of the electrons emitted from the carbon nanotube line 112. Under the action of an applied electric field, electrons emitted from the nanocarbon line 112 fly from the cathode 11 to the anode 12 and penetrate the anode 12 to bombard the phosphor layer 13, causing the phosphor layer 13 to emit light. That is, the direction of flight of the electrons generally proceeds in the direction of the central axis of the casing. Therefore, the shield pole 14 is disposed around the central axis of the housing 10. Preferably, the shield pole 14 conforms to the shape of the housing 10 and is disposed coaxially with the housing 10.

Referring to FIG. 2, the field emission pixel tube 200 of the second embodiment and the field emission pixel tube of the first embodiment The 100 is similar except that the shield electrode 24 is a cylindrical conductive film disposed on the inner wall or the outer wall of the casing 20. The shield electrode 24 may be formed of a metal having high conductivity such as gold, silver, copper or aluminum. Preferably, the shield electrode 24 is a gold film. The shield electrode 24 can be formed by sputtering or evaporation. When the shield pole 24 is disposed on the inner wall of the casing 20, it must be formed before the casing 20 is closed.

When the field emission pixel tube of each of the above embodiments is in operation, the cathode and the shield electrode are connected to a low potential, and the anode is connected to a high potential. Since the shielding pole can shield the high voltage of the anode, it can significantly reduce the electric field strength on the surface of the nanocarbon pipeline. The smaller the diameter of the field emission pixel tube, the more obvious the shielding effect is due to the closer the shielding pole is to the cathode. Due to the low electric field strength of the surface of the nanocarbon pipeline, its emission current is reduced, but its operating voltage is high. It meets the ideal working conditions of the field emission pixel tube, and has good emission effect and long service life.

In addition, since the shield electrode and the cathode are both at a low potential, the shield electrode has a repulsive effect on electrons emitted from the carbon nanotube line, and since the shield electrode is disposed around the nano carbon line, its electron repulsion causes the nano carbon line to be emitted. The electron beam is more concentrated toward the anode, avoiding flying to the inner wall of the casing 10, thereby improving the utilization of electrons and avoiding the generation of X-rays on the inner wall of the casing.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

10‧‧‧shell

11‧‧‧ cathode

12‧‧‧Anode

13‧‧‧Fluorescent layer

14‧‧‧Shielding pole

100‧‧ ‧ field emission pixel tube

102‧‧‧Lighting Department

111‧‧‧Support

Claims (9)

A field emission pixel tube comprising a casing, an anode and a cathode respectively disposed at two ends of the casing, the cathode comprising a carbon carbon pipeline, the casing is provided with a light exiting portion at one end, and the anode is disposed corresponding to the light exiting portion, and the improvement is The field emission pixel tube further includes a shielding electrode disposed around the nano carbon line on the surface of the housing, the shielding electrode being disposed coaxially with the housing. The field emission pixel tube of claim 1, wherein the shield is substantially annular. The field emission pixel tube of claim 1, wherein the shield is extremely conductive film. The field emission pixel tube according to claim 3, wherein the conductive film is a gold film, a silver film, a copper film or an aluminum film. The field emission pixel tube of claim 1, wherein the shielding electrode is disposed on an inner surface or an outer surface of the housing. The field emission pixel tube of claim 1, wherein the cathode comprises a support, and the nanocarbon pipeline is disposed on the support. The field emission pixel tube according to claim 7, wherein the nano carbon line and the support body are bonded by a conductive adhesive or one end of the nano carbon line is welded to the support body. The field emission pixel tube of claim 1, wherein the nano carbon line has a length of 0.1 mm to 10 mm. The field emission pixel tube of claim 1, wherein the nanocarbon line has a diameter of 1 micrometer to 1 millimeter.