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Ceramic envelope for intensity discharge lamp

Imported: 24 Feb '17 | Published: 24 Aug '04

Sugio Miyazawa

USPTO - Utility Patents

Abstract

A ceramic envelope for high intensity discharge lamp is provided including a cylindrical barrel section forming an electric discharge light emitting space; and having annular closing sections closing both ends of the barrel, respectively; and capillary sections that insert and fix an electric discharge electrode to protruded outwardly so as to be to oppose each other from the substantial center of both closing sections. The envelope essentially consists of alumina, and is formed to have light transmission properties by adding MgO. Then, the thickness of the barrel section at the boundary between the barrel section and the closing section is increased by providing a tapered section in the vicinity of the center of an electric discharge light emitting space. Thus, a high emitting envelope for high intensity discharge lamp capable of extending the service life of the lamp can be provided, even if the electric discharge space is cylindrical.

Description

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the present invention and, together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principle of the present invention.

FIG. 1 is a sectional view and a partially enlarged view of a ceramic envelope for high intensity discharge lamp illustrating a first embodiment of the present invention;

FIG. 2 is a sectional view and a partially enlarged view of a ceramic envelope for high intensity discharge lamp illustrating a second embodiment of the present invention;

FIG. 3 is a sectional view and a partially enlarged view of a ceramic envelope for high intensity discharge lamp illustrating a third embodiment of the present invention;

FIG. 4 is a sectional view and a partially enlarged view of a ceramic envelope for high intensity discharge lamp illustrating a fourth embodiment of the present invention; and

FIG.

5A and FIG. 5B are illustrative cross sections of a conventional ceramic envelope for high intensity discharge lamp having a cylindrical electric discharge light emitting space, wherein reference numeral

1 denotes a barrel section; reference numeral

2 denotes a closing section; reference numeral

3 denotes a capillary section; reference numeral

4 denotes a thickness change section; and reference numeral

4

a denotes a tapered section.

Claims

1. A ceramic envelope for a thigh intensity discharge lamp made of a light transmission ceramic material, comprising:

2. A ceramic envelope for a high intensity discharge lamp made of a light transmission ceramic material, comprising:

3. A ceramic envelope for high intensity discharge lamp made of a light transmission ceramic material, comprising:

4. A ceramic envelope for a high intensity discharge lamp made of a light transmission ceramic material, comprising:

5. The ceramic envelope for a high intensity discharge lamp as claimed in claim 1, wherein a surface roughness Ra of an interior surface of said barrel section is in a range of 0.01 m to 0.4 m, and an additive concentration of the surface of said barrel section is ±

4 or less of that in the vicinity of the center of the thickness.

6. The ceramic envelope for thigh intensity discharge lamp as claimed in claim 3, wherein said additive consists of at least one of Sc

2O

3, MgO, ZrO

2, Y

2O

3, and lanthanoid based rare earth oxides.

7. The ceramic envelope for a high intensity discharge lamp as claimed in claim 2, wherein a surface roughness Ra of an interior surface of said barrel section is in a range of 0.01 m to 0.4 m, and an additive concentration of the surface of said barrel section is ½ or less of that in the vicinity of the center of the thickness.

8. The ceramic envelope for a high intensity discharge lamp as claimed in claim 4, wherein a surface roughness Ra of an interior surface of the barrel section is in a range of 0.01 m to 0.4 m, and an additive concentration of the surface of said barrel section is ½ or less of that in the vicinity of the center of the thickness.

9. The ceramic envelope for a high intensity discharge lamp as claimed in claim 5, wherein said additive consists of at least one of Sc

2O

3, MgO, ZrO

2, Y

2O

3 and lanthanoid based rare earth oxides.

10. The ceramic envelope for a high intensity discharge lamp as claimed in claim 7, wherein said additive consists of at least one of Sc

2O

3, MgO, ZrO

2, Y

2O

3 and lanthanoid based rare earth oxides.

11. The ceramic envelope for a high intensity discharge lamp as claimed in claim 8, wherein said additive consists of at least one of Sc

2O

3, MgO, ZrO

2, Y

2O

3 and lanthanoid based rare earth oxides.