Title:
DISCHARGE BULB
Document Type and Number:
Japanese Patent JP3634692
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To eliminate the possibility that the emission tube portion of an arc tube composed so that an arc tube is almost concentrically surrounded by a shroud tube will be fructured during lighting of the arc tube.
SOLUTION: Clearance g1 between the uppermost point P1 on outer face 20e of emission tube portion 20a and inner wall face 18c of shroud tube 18 is set at g1 ≥0.3 mm based on the prescribed experimental result. This prevents rapid creation of devitrification by heat accumulation phenomenon and dopant diffusion phenomenon to develop many micro-cracks at the upper end where temperature becomes the highest in the emission tube portion 20a during the lighting of the discharge valve. As a result, generation of an explosion of the emission tube portion 20a with the micro-cracks as the starting points can be prevented in advance.
Inventors:
Shinichi Irizawa
Takeshi Fukushiro
Yuritaka Oshima
Yuichi Nagasawa
Takeshi Fukushiro
Yuritaka Oshima
Yuichi Nagasawa
Application Number:
JP28940099A
Publication Date:
March 30, 2005
Filing Date:
October 12, 1999
Export Citation:
Assignee:
Koito Manufacturing Co., Ltd.
International Classes:
H01J61/34; (IPC1-7): H01J61/34
Domestic Patent References:
| JP6020645A | ||||
| JP7192695A | ||||
| JP9180680A | ||||
| JP1292740A | ||||
| JP63105456A |
Attorney, Agent or Firm:
Takashi Moriyama