Flash discharge tube and method for producing the same

• US 20010041491A1
• Filed: 05/02/2001
• Published: 11/15/2001
• Est. Priority Date: 12/16/1997
• Status: Active Grant

• Current Assignee: Fujifilm Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Hideaki Takeuchi, Shouji Nishida, Tatuya Isomura, Tsutomu Tobita
• Inventors: Takeuchi, Hideaki, Tobita, Tsutomu, Nishida, Shouji, Isomura, Tatuya
• Granted Patent: US 6,604,973 B2
• Time in Patent Office: Days
• US Class Current: 445/26
• CPC Class Codes: H01J 61/35 provided with coatings on the walls thereof; Selection of materials for the coatings using coloured coatings H01J61/40; using luminescent coatings H01J61/42
• CPC Class Codes: H01J 61/547 using an auxiliary electrode outside the vessel H01J61/544 takes precedence
• CPC Class Codes: H01J 61/80 Lamps suitable only for intermittent operation, e.g. flash lamp
• CPC Class Codes: H01J 9/14 of non-emitting electrodes
• CPC Class Codes: H01J 9/20 Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
• CPC Class Codes: H01J 9/323 Sealing leading-in conductors into a discharge lamp or a gas-filled discharge device

Abstract

In an anode-side assembling process, a first end of a glass tube is fused to a rearward end of an electrode bar secured to an anode-side lead to produce a primary sealed product. In a cathode-side assembling process, a ring-shaped cathode is secured by caulking to a forward end portion of an electrode bar secured to a forward end of a cathode-side lead to produce a cathode member. In an assembling process, a second end of the glass tube of the primary sealed product is fused to a rearward end of the electrode bar secured to the cathode-side lead of the cathode member to produce a xenon discharge tube. A trigger electrode, which is composed of a transparent conductive film, is formed on a surface of the glass tube so that the light-transmissive sealed tube-coating ratio specified by the transparent conductive film is within a range of 5 to 30%.

Claims

1. A flash discharge tube comprising a trigger electrode composed of a transparent conductive film formed on a surface of a light-transmissive sealed tube, wherein:

a light-transmissive sealed tube-coating ratio specified by said transparent conductive film is within a range of 5 to 30%.

2. The flash discharge tube according to

claim 1

, wherein said light-transmissive sealed tube is coated with said transparent conductive film in a band-shaped configuration so that said light-transmissive sealed tube-coating ratio is not less than 5% toward a center in an axial direction starting from a portion near to a surface position on said light-transmissive sealed tube on an identical cross section perpendicular in said axial direction to a forward end of a cathode provided coaxially with a central axis of said light-transmissive sealed tube at one end of said light-transmissive sealed tube.

3. A method for producing a flash discharge tube comprising a trigger electrode composed of a transparent conductive film formed on a surface of a light-transmissive sealed tube, said method comprising the steps of:

coating said surface of said light-transmissive sealed tube in accordance with an immersion method with a solution of an organic metal compound containing a major component metal of indium or tin as a transparent conductive material;

drying said surface followed by allowing hot air to blow against only a portion for forming said transparent conductive film, of a coating layer of said transparent conductive material to perform local calcination by oxidizing indium or tin contained in said transparent conductive material; and

then

removing a non-calcinated portion of said transparent conductive material by means of etching with an acidic solution to form said transparent conductive film in a band-shaped configuration on said surface of said light-transmissive sealed tube.

4. The method for producing said flash discharge tube according to

claim 3

, wherein at least one of film-forming positions for said transparent conductive film is decided when said light-transmissive sealed tube is immersed.

5. The method for producing said flash discharge tube according to

claim 3

, further comprising:

an anode-side shooting step of inserting a large number of anode-side leads into a large number of holes of an anode-side jig provided with said large number of holes respectively;

an anode-side glass tube-inserting step of inserting first ends of said large number of glass tubes into said anode-side jig so that anodes of said corresponding anode-side leads are respectively surrounded thereby;

a primary sealing step of producing primary sealed products by applying electric power to heat said anode-side jig so that said large number of glass tubes are fused to said corresponding anode-side leads respectively;

a cathode-side shooting step of inserting a large number of cathode-side leads into a large number of holes of a cathode-side jig provided with said large number of holes respectively;

a cathode-side glass tube-inserting step of inserting second ends of said glass tubes of said primary sealed products into said cathode-side jig so that cathodes of said corresponding cathode-side leads are respectively surrounded thereby; and

a secondary sealing step of applying electric power to heat said cathode-side jig in a xenon gas atmosphere so that said glass tubes of said primary sealed products are fused to said corresponding cathode-side leads respectively.

6. The method for producing said flash discharge tube according to

claim 5

, further comprising a lead-cutting step of cutting said anode-side lead and said cathode-side lead of a secondary sealed product discharged from said secondary sealing step, to have predetermined lengths respectively.

7. The method for producing said flash discharge tube according to

claim 5

, wherein said anode-side jig to be used is a jig in which a large number of recesses, which are capable of inserting said first ends of said glass tubes thereinto, are formed through a first principal surface thereof, and anode-side lead insertion holes, which penetrate up to a second principal surface of said anode-side jig and which are capable of inserting said anode-side leads thereinto, are provided through central portions of bottoms of said respective recesses.

8. The method for producing said flash discharge tube according to

claim 5

, wherein said cathode-side jig to be used is a jig in which a large number of recesses, which are capable of inserting said second ends of said glass tubes thereinto, are formed through a first principal surface thereof, and cathode-side lead insertion holes, which penetrate up to a second principal surface of said cathode-side jig and which are capable of inserting said cathode-side leads thereinto, are provided through central portions of bottoms of said respective recesses.

9. The method for producing said flash discharge tube according to

claim 5

, wherein said anode-side shooting step includes insertion of a glass bead into said anode-side lead.

10. The method for producing said flash discharge tube according to

claim 5

, wherein a glass bead is attached to said cathode-side lead to be inserted into said cathode-side jig in said cathode-side shooting step, before being inserted.

11. The method for producing said flash discharge tube according to

claim 9

, further comprising a bead-applying step of applying electric power to head said anode-side jig so that said glass bead is fused to said anode-side lead.

12. The method for producing said flash discharge tube according to

claim 5

, further comprising a cathode-caulking step of inserting said cathode into a forward end portion of said cathode-side lead so that said cathode is fixed by caulking.

13. The method for producing said flash discharge tube according to

claim 12

, wherein said cathode-caulking step is carried out to fix, by caulking, said cathode to said forward end portion of said cathode-side lead in which a glass bead is previously attached to said forward end portion.

14. The method for producing said flash discharge tube according to

claim 5

, wherein said secondary sealing step comprises:

a cleaning step of removing impurities from at least the inside of said glass tube by means of exposure to a negative pressure atmosphere prior to said application of electric power to heat said cathode-side jig;

a sealing step of applying electric power to heat said cathode-side jig in a negative pressure atmosphere and in a xenon gas atmosphere; and

a cooling step of cooling at least said cathode-side jig in a negative pressure atmosphere.