Gas discharge tube

• US 6,741,036 B1
• Filed: 10/17/2000
• Issued: 05/25/2004
• Est. Priority Date: 09/07/1998
• Status: Expired due to Fees

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: Adachi, Kouzou, Ito, Yoshinobu, Matui, Ryotaro, Ikedo, Tomoyuki
• Primary Examiner(s): Patel, Vip
• Assistant Examiner(s): BERCK, KENNETH A
• Application Number:
  US09/688,927
• Time in Patent Office: 1,316 Days
• Field of Search: 313/634, 313/613, 313/614, 313/615, 313/239, 313/292, 313/592, 313/593, 313/594, 313/595, 313/581-588, 313/623, 313/308
• US Class Current: 313/634
• CPC Class Codes: H01J 61/10 Shields, screens, or guides for influencing the discharge
• CPC Class Codes: H01J 61/68 Lamps in which the main discharge is between parts of a current-carrying guide, e.g. halo lamp
• CPC Class Codes: H01J 63/02 Details, e.g. electrode, gas filling, shape of vessel
• CPC Class Codes: H01J 63/08 Lamps with gas plasma excited by the ray or stream

Abstract

A flange portion is integrally formed with a stem which forms a sealing envelope for a gas discharge tube. Accordingly, operation for building and fixing the flange portion is not necessary, so that lamp assembly operation is simplified, and mass production is facilitated. In addition, when a gas discharge tube is to be fixed to an external stem setting portion, lamp setting is enabled at higher precision by utilizing positioning holes formed in the flange portion in advance.

Claims

1. A gas discharge tube having a sealed envelope at least a part of which transmits light, said

sealed envelope being filled with a gas and being provided with anode and cathode sections disposed therein, electric discharge being generated between said anode and cathode sections, so that the light-transmitting part of said sealed envelope emits predetermined light outside,

said sealing envelope comprising:

a stem for securing said cathode and anode section by way of respective stem pins independent from each other; and

a side tube, at least part of which is made of a light transmitting material, surrounding said cathode and anode sections and being joined to said stem, and

wherein said stem has an integrally formed flange portion extending in a direction perpendicular to an axial direction of said side tube and having a positioning reference portion when attaching said gas discharge tube to an external fixing member.

2. A gas discharge tube according to claim 1, wherein said positioning reference portion has a positioning hole or notch for inserting a positioning pin inserted another end in a positioning hole formed in a stem setting portion of an external fixing member where said gas discharge tube is to be attached, or inserting a positioning pin standing upright from said stem setting portion.

3. A gas discharge tube according to claim 1, wherein said positioning portion has a projecting portion projecting from said flange portion laterally, or a cut-off portion formed on an outer surface of said flange portion so as to conform to a shape of a stem setting portion of said external fixing member to which said gas discharge tube is to be mounted.

4. A gas discharge tube according to claim 1, wherein said flange portion has an outer shape of a predetermined polygon.

5. A gas discharge tube according to claim 1, further comprising:

an anode support plate in contact with a surface of said stem which is inside said sealing envelope, and supporting said anode section on an opposite surface thereof;

a ceramic spacer in contact with an exposed surface of said anode support plate and having an opening for exposing said anode section therethrough; and

a ceramic spacer in contact with an exposed surface of said anode support plate and having an opening for exposing said anode section therethrough; and

a converging electrode plate in contact with said exposed surface of said spacer to oppose said anode section having a converging opening coaxial with said opening of said spacer, said converging electrode plate being made of a conductive member.

6. A gas discharge tube according to claim 5, wherein said positioning reference portion has a positioning hole or notch for inserting a positioning pin inserted another end in a positioning hole formed in a stem setting portion of an external fixing member where said gas discharge tube is to be attached, or inserting a positioning pin standing upright from said stem setting portion.

7. A gas discharge tube according to claim 5, wherein said positioning portion has a projecting portion projecting from said flange portion laterally, or a cut-off portion formed on an outer surface of said flange portion so as to conform to a shape of a stem setting portion of said external fixing member to which said gas discharge tube is to be mounted.

8. A gas discharge tube according to claim 5, wherein said flange portion has an outer shape of a predetermined polygon.

9. A gas discharge tube according to claim 1, wherein said integrally formed flange portion extends horizontally in the direction perpendicular to the axial direction of said side tube.

10. A gas discharge tube according to claim 1, wherein said side tube is made entirely of light transmitting material.