Field emission lamp and method for making the same

• US 20070247071A1
• Filed: 11/21/2006
• Published: 10/25/2007
• Est. Priority Date: 03/22/2006
• Status: Active Grant

• Current Assignee: Hon Hai Precision Industry Co., Ltd., Tsinghua University
• Original Assignee: Hon Hai Precision Industry Co., Ltd., Tsinghua University
• Inventors: Qian, Li, Fan, Shou-Shan, Liu, Peng, Liu, Liang, Wei, Yang, Tang, Jie
• Granted Patent: US 7,915,799 B2
• Time in Patent Office: Days
• US Class Current: 313/634
• CPC Class Codes: H01J 63/02 Details, e.g. electrode, gas filling, shape of vessel
• CPC Class Codes: H01J 63/04 Vessels provided with luminescent coatings; Selection of materials for the coatings
• CPC Class Codes: H01J 63/06 Lamps with luminescent screen excited by the ray or stream
• CPC Class Codes: H01J 9/025 of field emission cathodes
• CPC Class Codes: H01J 9/244 specially adapted for cathode ray tubes H01J9/241, H01J9/26 take precedence

Abstract

A field emission lamp generally includes a bulb having an open end, a lamp head disposed at the open end of the bulb, an anode, and a cathode. The anode includes an anode conductive layer formed on an inner surface of the bulb, a fluorescent layer deposited on the anode conductive layer, and an anode electrode electrically connected with the anode conductive layer and the lamp head. The cathode includes an electron emission element and a cathode electrode electrically connected with the electron emission element and the lamp head. The electron emission element has an electron emission layer. The electron emission layer includes getter powders therein to exhaust unwanted gas in the field emission lamp, thereby ensuring the field emission lamp with a high degree of vacuum during operation thereof. A method for making such field emission lamp is also provided.

Claims

1. A field emission lamp comprising:

a transparent bulb having an open end;

a lamp head disposed on the open end of the bulb;

an anode comprising an anode conductive layer, a fluorescent layer, and an anode electrode, the anode conductive layer being formed on an inner surface of the bulb, the fluorescent layer being created on a portion of a surface of the anode conductive layer to result in an exposed portion of the anode conductive layer, the anode electrode being disposed on the open end of the bulb, the anode electrode electrically connecting the anode conductive layer with the lamp head; and

a cathode comprising a cathode electrode and an electron emission element, an end of the cathode electrode being disposed in the open end of the bulb and insulated from the anode electrode, the cathode electrode being electrically connected with the lamp head, the electron emission element being disposed on an opposite end of the cathode electrode and electrically connected therewith, the electron emission element having an electron emission layer thereon, the electron emission layer being comprised of a glass matrix and a plurality of carbon nanotubes, getter powders, and metallic conductive particles dispersed therein.

2. The field emission lamp as described in claim 1, wherein the getter powders are comprised of a non-evaporating getter material.

3. The field emission lamp as described in claim 1, wherein an average diameter of the getter powders is in the range from about 1 micrometer to about 10 micrometers.

4. The field emission lamp as described in claim 1, wherein getter powders are comprised of at least one material selected from the group consisting of titanium, zirconium, hafnium, thorium, aluminum, and thulium.

5. The field emission lamp as described in claim 1, wherein an average diameter of the nanotubes is in the range from about 1 nanometer to about 100 nanometers, and an average length thereof is in the range from about 5 micrometers to about 15 micrometers.

6. The field emission lamp as described in claim 1, wherein the metallic conductive particles are made of a material selected from indium tin oxide and silver, and an average diameter thereof is in the range from about 0.1 micrometer to about 10 micrometers.

7. The field emission lamp as described in claim 1, wherein the cathode electrode comprises an electrode head, a cathode down-lead wire, and a hollow glass column, the electrode head being disposed on a middle portion of the lamp head, the cathode down-lead wire electrically connecting the electrode head with the electron emission element, the hollow glass column receiving the cathode down-lead wire, an end of the column supporting the electron emission element and the other end thereof being secured in the open end of the bulb.

8. The field emission lamp as described in claim 1, wherein the anode electrode comprises a pair of anode down-lead wires, an anode down-lead pole, and an anode down-lead ring, the ring is disposed on the exposed portion of the anode conductive layer, the anode down-lead pole is disposed on the open end of the bulb, one of the anode down-lead wires electrically connects an end of the anode down-lead pole with the ring, and the other anode down-lead wire electrically connects the other end of the anode down-lead pole with the lamp head.

9. The field emission lamp as described in claim 1, wherein the anode conductive layer is an indium tin oxide film.

10. A method for making a field emission lamp comprising the step of:

providing a transparent glass bulb with an open end, an anode electrode, a cathode electrode, a metallic base body, a lamp head, and a plurality of carbon nanotubes, metallic conductive particles, glass particles and getter powders, the bulb comprising an anode conductive layer on an inner surface thereof and a fluorescent layer on a surface of the anode conductive layer;

mixing the nanotubes, the metallic conductive particles, the glass particles and the getter powders in organic medium to form an admixture;

forming a layer of the admixture on a surface of the body;

drying and baking the admixture at a temperature of about 300°

C. to about 600°

C. to form an electron emission layer on the body thereby obtaining an electron emission element; and

assembling the bulb, the anode electrode, the cathode electrode and the electron emission element; and

sealing the open end of the bulb at a temperature of about 400°

C. to about 500°

C. in order to secure the anode electrode and the cathode electrode and evacuating the bulb interior, assembling the lamp head and electrically connecting the lamp head with the anode electrode and the cathode electrode, respectively, thereby yielding the field emission lamp.

11. The method for making the field emission lamp as described in claim 10, wherein the getter powders are made of a non-evaporating getter material having an activity temperature of about 300°

C. to about 500°

C.

12. The method for making the field emission lamp as described in claim 10, wherein an average diameter of the glass particles is in the range from about 10 nanometers to about 100 nanometers, and the melting temperature thereof is in the range from about 350°

C. to about 600°

C.

13. The method for making the field emission lamp as described in claim 10, wherein the organic medium is composed by a certain amount of terpineol, and a smaller amount of dimethyl phthalate and ethyl cellulose.

14. The method for making the field emission lamp as described in claim 10, wherein the percent by mass of the getter powders in the admixture is in the range from about 40% to about 80%.

15. The method for making the field emission lamp as described in claim 10, wherein the process of mixing the nanotubes, the getter powders, the glass particles, and the metallic conductive particles is performed at a temperature of about 60°

C. to about 80°

C. for a time of about 3 hours to about 5 hours.

16. The method for making the field emission lamp as described in claim 10, wherein the drying and baking processes are performed at least one of in a vacuum condition and under a flow of a protective gas.

17. The method for making the field emission lamp as described in claim 10, wherein, after forming the electron emission element, a surface of the electron emission layer is at least one of abraded and etched in order to expose ends of the nanotubes.