Gas discharge tube

• US 7,288,893 B2
• Filed: 02/12/2004
• Issued: 10/30/2007
• Est. Priority Date: 02/12/2003
• Status: Active Grant

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: Matsushita, Koji, Ito, Masaki, Ito, Yoshinobu
• Primary Examiner(s): Williams; Joseph
• Assistant Examiner(s): Won; Bumsuk
• Application Number:
  US10/544,465
• Publication Number:
  US 20060145580A1
• Time in Patent Office: 1,356 Days
• Field of Search: 313/103.R, 313609-613, 313/623, 313/634, 313/637, 313542-544, 250/214.VT
• US Class Current: 313/609
• CPC Class Codes: H01J 61/68 Lamps in which the main discharge is between parts of a current-carrying guide, e.g. halo lamp

Abstract

A gas discharge tube 10 of the present invention generates an electric discharge between an anode part 24 and a cathode part 52 disposed inside a sealed container 12 in which gas has been sealed. The gas discharge tube 10 includes an electric discharge path restricting part 28 which is cylindrical and disposed between the anode part and the cathode part, and which has a throughhole 46 for narrowing an electric discharge path between the anode part and the cathode part; and a supporting part 30 which supports the electric discharge path restricting part and which is electric insulating. The electric discharge path restricting part is provided at its tip portion with a projecting part 44 which is cylindrical and projects toward the cathode part side. Letting the outer diameter and height of the projecting part 44 be “D” and “H,” respectively, then D/H is in the range of 0.5 to 2.0. With this structure, it is possible to generate an intense electric field in the vicinity of the tip of the projecting part. This can decrease a startup voltage, thereby ensuring the generation of an electric discharge.

Claims

1. A gas discharge tube comprising:

a sealed container in which gas is contained;

an anode part disposed in said sealed container;

a cathode part defining an electric discharge part for generating an electric discharge with said anode part, said cathode part being disposed inside said sealed container in such a manner as to be distanced from said anode part;

an electric discharge path restricting part being cylindrical and conductive and having a throughhole for narrowing said electric discharge path, said electric discharge path restricting part being disposed between said anode part and said cathode part, and being adapted to be electrically connected with an external power source; and

an electric-discharge-path-restricting-part supporting part for supporting said electric discharge path restricting part, said supporting part being electrically insulating,

wherein said electric discharge path restricting part has a projecting part which is cylindrical and projects toward said cathode part side, and a ratio (D/H) of an outer diameter (D) of said projecting part to a height (H) of said projecting part is in a range of 0.5 to 2.0.

2. The gas discharge tube according to claim 1, wherein the outer diameter of said projecting part of said electric discharge path restricting part is in a range of 1.0 mm to 2.0 mm.

3. The gas discharge tube according to claim 1, wherein said throughhole in said electric discharge path restricting part includes a small hole part which is provided on said anode part side and has a constant inner diameter, and an increased diameter hole part which is linked with said small hole part and extends toward said cathode part side.

4. The gas discharge tube according to claim 3, wherein said increased diameter hole part has a conical inner peripheral surface, a depth (A) in a range of 0.3 mm to 1.3 mm and an opening angle (θ

) in a range of 60°

to 90°

.

5. The gas discharge tube according to claim 1, wherein the gas in said sealed container is heavy hydrogen gas.