Field emission cathode device and driving method

Patent metadata

Field	Value
Publication number	US-9536695-B2
Application number	US-201313863538-A
Country	US
Kind code	B2
Filing date	Apr 16, 2013
Priority date	Dec 29, 2012
Publication date	Jan 3, 2017
Grant date	Jan 3, 2017

Abstract

A driving method includes providing a field emission cathode device. The field emission cathode device includes a cathode electrode, an electron emission layer electrically connected to the cathode electrode, a first gate electrode spaced from the cathode electrode by a first dielectric layer, and a second grid electrode spaced from the first gate electrode by a second dielectric layer. The second dielectric layer has a second opening. A first voltage is supplied to the cathode electrode, a second voltage is supplied to the first gate electrode, and a third voltage is supplied to the second grid electrode, to extract electrons from the electron emission layer to a space formed by the second opening, until the electrons of the space saturate. The third voltage is greater than the second voltage, such that the electrons of the space are emitted through the second grid electrode.

First claim

What is claimed is:

1. A driving method, comprising steps of:
providing a field emission cathode device, the field emission cathode device comprising:
a cathode electrode;
an electron emission layer electrically connected to the cathode electrode;
a first gate electrode spaced from the cathode electrode by a first dielectric layer, wherein the first gate electrode has an opening opposite to the electron emission layer; and
a second grid electrode located on a surface of the first gate electrode away from the cathode electrode and spaced from the first gate electrode by a second dielectric layer, wherein the second dielectric layer has a second opening such that a part of the cathode electrode is exposed, and the second grid electrode has a mesh opposite to the electron emission layer;

supplying a first voltage to the cathode electrode, supplying a second voltage to the first gate electrode, and supplying a third voltage to the second grid electrode, to extract electrons from the electron emission layer to a space formed by the second opening, until the electrons of the space saturate, wherein the first voltage is less than the second voltage, and the third voltage is less than or equal to the second voltage; and
amplifying the third voltage after the electrons of the space saturate, such that the third voltage is greater than the second voltage and the electrons of the space are emitted through the second grid electrode.

2. The field emission cathode device of claim 1 , wherein the first gate electrode is a grid electrode and covers the first opening.

3. The field emission cathode device of claim 2 , wherein a transparency of the first gate electrode is less than or equal to a transparency of the second grid electrode.

4. The field emission cathode device of claim 3 , wherein the difference between the transparency of the first gate electrode and the transparency of the second grid electrode is in a range from about 0 to about 10%.

5. The field emission cathode device of claim 1 , wherein the first gate electrode and the second grid electrode are made of at least two stacked carbon nanotube films.

6. The field emission cathode device of claim 5 , wherein the carbon nanotube film comprises a plurality of successive and oriented carbon nanotubes joined end-to-end by van der Waals attractive force therebetween.

7. The field emission cathode device of claim 6 , wherein an angle between aligned directions of the carbon nanotubes in two adjacent carbon nanotube films is in a range from about 0 degree to about 90 degrees.

8. The field emission cathode device of claim 1 , wherein the first voltage is about 0 volt, the second voltage is in a range from about 30 volts to about 300 volts, and the third voltage is in a range from about −100 volts to about 250 volts.

9. A driving method, comprising steps of:
providing a field emission cathode device, the field emission cathode device comprising:
a cathode electrode;
an electron emission layer electrically connected to the cathode electrode;
a first gate electrode spaced from the cathode electrode by a first dielectric layer, wherein the first gate electrode has an opening opposite to the electron emission layer; and
a second grid electrode located on a surface of the first gate electrode away from the cathode electrode and spaced from the first gate electrode by a second dielectric layer, wherein the second dielectric layer has a second opening such that a part of the cathode electrode is exposed, and the second grid electrode has a mesh opposite to the electron emission layer;

supplying a first voltage to the cathode electrode, supplying a second voltage to the first gate electrode, and supplying a third voltage to the second grid electrode, to extract electrons from the electron emission layer to a space formed by the second opening, until the electrons of the space saturates, wherein the first voltage is less than the second voltage, and the third voltage is less than or equal to the second voltage; and
providing an anode electrode supplied a voltage after the electrons of the space saturate, such that the electrons of the space are emitted through the second grid electrode.

10. The field emission cathode device of claim 9 , wherein the first voltage is about 0 volt, the second voltage is in a range from about 30 volts to about 300 volts, and the third voltage is in a range from about −100 volts to about 250 volts.

11. The field emission cathode device of claim 9 , wherein the first gate electrode and the second grid electrode are made of at least two stacked carbon nanotube films.

12. The field emission cathode device of claim 1 , wherein before amplifying the third voltage, equipotential lines of the second grid electrode is substantially parallel to the electron emission layer, causing the electrons extracted from the electron emission layer to be in the space but not emit through the second grid electrode.

13. The field emission cathode device of claim 1 , wherein the electrons of the space are controlled to emit through the second grid electrode by adjusting the third voltage, and the emission of the electrons of the space is not controlled by the electron emission layer.

14. A field emission cathode device, comprising:
an insulating substrate;
a cathode electrode located on a surface of the insulating substrate;
a first dielectric layer located on a surface of the cathode electrode or the surface of the insulating substrate, wherein the first dielectric layer defines a first opening such that part of the cathode electrode is exposed;
an electron emission layer located on the surface of the cathode electrode and electrically connected to the cathode electrode, wherein the surface of the cathode electrode is exposed through the first opening;
a first gate electrode located on a surface of the first dielectric layer;
a second dielectric layer located on a surface of the first gate electrode and defined a second opening, a part of the cathode electrode is exposed; and
a second grid electrode extending from the second dielectric layer and opposite to the electron emission layer, wherein the second grid electrode covers the second opening, the second grid electrode has a mesh opposite to the electron emission layer, the first gate electrode is a grid electrode, a transparency of the first gate electrode is less than a transparency of the second grid electrode, and an area of each mesh of the first gate electrode is greater than an area of each mesh of the second grid electrode.

15. The field emission cathode device of claim 14 , wherein the difference between the transparency of the first gate electrode and the transparency of the second grid electrode is in a range from about 0 to about 10%.

16. The field emission cathode device of claim 14 , wherein the first gate electrode and the second grid electrode are made of alloy, conductive slurry, carbon nanotube, or ITO.

17. The field emission cathode device of claim 16 , wherein the first gate electrode and the second grid electrode are made of at least two stacked carbon nanotube films, and the carbon nanotube film comprises a plurality of successive and oriented carbon nanotubes joined end-to-end by van der Waals attractive force therebetween.

18. The field emission cathode device of claim 17 , wherein an angle between aligned directions of the carbon nanotubes in two adjacent carbon nanotube films is in a range from about 0 degrees to about 90 degrees.

19. The field emission cathode device of claim 14 , wherein thicknesses of the

Assignees

• Univ Tsinghua
• Hon Hai Prec Ind Co Ltd

Inventors

• Liu Peng
• Fan Shou-Shan

Classifications

• H01J31/127

  using large area or array sources, i.e. essentially a source for each pixel group · CPC title

• H05B41/14

  Circuit arrangements · CPC title

• H01J2201/30469

  Carbon nanotubes (CNTs) · CPC title

• H01J1/304 Primary

  Field-emissive cathodes · CPC title