Light-emitting device configured to emit light by a creeping discharge of an emitter

• US 7,830,077 B2
• Filed: 04/06/2006
• Issued: 11/09/2010
• Est. Priority Date: 04/07/2005
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Kato, Junichi, Ueno, Iwao
• Primary Examiner(s): Patel; Nimeshkumar D
• Assistant Examiner(s): ZIMMERMAN, GLENN D
• Application Number:
  US11/910,622
• Publication Number:
  US 20090236964A1
• Time in Patent Office: 1,678 Days
• Field of Search: 313/582.586, 313/486, 313/483, 313/484, 313/485, 313/487, 313/489, 313/491, 313/492, 445/24, 345/60, 315/169.4, 257/109
• US Class Current: 313/483
• CPC Class Codes: H01J 11/12 with main electrodes provided on both sides of the discharge space
• CPC Class Codes: H01J 11/36 Spacers, barriers, ribs, partitions or the like

Abstract

A light-emitting device according to the present invention includes: first insulators (4) arranged so as to face each other; an emitter (2) arranged between the first insulators; a second insulator (5) functioning as a base for the first insulators and the emitter; an electrode (6) arranged to face, or contact with, the first insulators partially; another electrode (10) contacting with the second insulator and interposing the second insulator between the electrode and itself; and a light-transmitting substrate (8) that faces the second insulator with the first insulators interposed somewhere and with the emitter interposed elsewhere. If the first insulators are extended to reach the light-transmitting substrate on a cross section including the first and second insulators, the emitter and the light-transmitting substrate, the ratio of the cross-sectional area of the emitter to the combined cross-sectional area of the first and second insulators and the light-transmitting substrate is defined so as to fall within a predetermined range.

Claims

1. A light-emitting device comprising:

a first insulator, including a plurality of portions that are arranged so as to face each other;

an emitter, which includes fluorescent particles and which is arranged in a space that is defined by those portions of the first insulator, wherein the emitter has a porous surface layer and is configured to emit light by a creeping discharge of the emitter, the creeping discharge being an electrical discharge that is produced in the porous surface layer of the emitter;

a second insulator, which functions as a base for the first insulator and the emitter;

a plurality of electrodes to generate an electric field in the space and the porous surface layer of the emitter; and

a substrate, which faces the second insulator with the emitter interposed between them, wherein the ratio A2/A1 of the cross-sectional area A2 of the emitter to the cross-sectional area A1 of a range surrounded with the first and second insulators and the substrate is greater than 0.4 but less than 1, the cross-sectional area A2 of the emitter and the cross-sectional area A1 of the range being on a plane that is perpendicular to the surface of the second insulator and that passes the center of the space.

2. The light-emitting device of claim 1, wherein the first and second insulators are made of the same material.

3. The light-emitting device of claim 1, wherein the first and second insulators have a dielectric constant of 5 or more.

4. The light-emitting device of claim 1, wherein one of the first and second insulators has a dielectric constant of 30 or more and the other insulator has a dielectric constant of 5 or more.

5. The light-emitting device of claim 1, wherein the first and second insulators are made of either a glass material or a mixture of a glass material and a metal oxide.

6. The light-emitting device of claim 1, wherein the electrodes include a front-side electrode and a backside electrode that are arranged on two opposite sides of the emitter, the front-side electrode being covered with an insulating layer.

7. The light-emitting device of claim 6, wherein the insulating layer includes an alkaline earth metal oxide.

8. The light-emitting device of claim 1, wherein the entire emitter is porous.

9. The light-emitting device of claim 1, wherein a layer of a gas is present between the emitter and the substrate.

10. The light-emitting device of claim 9, wherein the gas includes at least one of oxygen and nitrogen.

11. The light-emitting device of claim 10, wherein the at least one of oxygen and nitrogen accounts for at least 1 volume % of the gas.

12. The light-emitting device of claim 1, wherein the gas is a mixture including xenon, which accounts for 2 volume % or less of the mixture.

13. The light-emitting device of claim 9, wherein the gas has a pressure of 5×

10³ Pa to 9×

10⁴ Pa.

14. The light-emitting device of claim 9, wherein at the center of the space, the average thickness of the gas layer is smaller than that of the emitter.

15. The light-emitting device of claim 1, wherein each said portion of the first insulator has a rib structure that protrudes from the second insulator toward the substrate.

16. The light-emitting device of claim 1, wherein those portions of the first insulator define barriers that divide a plurality of self-emitting cells from each other between the second insulator and the substrate.

17. The light-emitting device of claim 16, wherein a gap is left between the barriers and the substrate.