Title:
放電管
Document Type and Number:
Japanese Patent JP4366655
Kind Code:
B2
Abstract:
The luminescent brightness of discharge tubes is improved by increasing the current density of the tube current. A discharge tube (1) is provided with a bulb (2) which comprises opposite ends (2a) each having an electrode (4) and being of circularly annular sectional shape, an intermediate section (2b) which is of non-circularly annular sectional shape, which is formed between the opposite ends (2a) and which is smaller in radial cross-sectional area than the opposite ends (2a), and a connecting section (2c) for connecting the opposite ends (2a) with the intermediate section (2b). Since the intermediate section (2b) of non-circularly annular sectional shape is smaller in sectional area than the opposite ends (2a) of circularly annular sectional shape, the current density of the tube current flowing through the intermediate section (2b) between the electrodes (4) increases over conventional bulbs, making it possible to improve the luminescent brightness of the discharge tube (1). Further, since the electrodes (4) of conventional circular sectional shape can be disposed in the opposite ends (2a) of circularly annular sectional shape, the electrodes (4), which are inexpensive and of general circular sectional shape, can be used.
Inventors:
Toyomi Yamashita
Saito Takuo
Saito Takuo
Application Number:
JP2004162054A
Publication Date:
November 18, 2009
Filing Date:
May 31, 2004
Export Citation:
Assignee:
Sanken Electric Co., Ltd.
International Classes:
H01J61/33; F21V8/00; G02F1/1335
Domestic Patent References:
| JP2000260216A | ||||
| JP2004063146A | ||||
| JP5089835A | ||||
| JP4312755A | ||||
| JP6230229A |
Foreign References:
| US2267118 | ||||
| US2961565 |
Attorney, Agent or Firm:
Keiichi Shimizu