Claims
- 1. An electric lamp, comprising:
- a lamp envelope sealed in a gas tight manner and defining a longitudinal lamp axis;
- a gas discharge sustaining filling within said lamp envelope;
- at least a pair of discharge electrodes within said lamp envelope between which a gas discharge is maintained during lamp operation, said discharge electrodes having distal ends arranged in opposed, axially spaced relationship along said longitudinal axis within said lamp envelope; and
- means for connecting said discharge electrodes to a source of electric potential exterior to said lamp envelope,
- at least one of said discharge electrodes including a tip portion at its distal end on which the gas discharge terminates during lamp operation, said tip portion comprising (i) a mesh body and (ii) an electron emitter material carried by said mesh body, said emitter material being a mixed oxide selected from the group consisting of Ba.sub.4 Ta.sub.2 O.sub.9 and Ba.sub.5 Ta.sub.4 O.sub.15.
- 2. An electric lamp according to claim 1, wherein said means for connecting includes a conductive feed-through extending through said lamp envelope in a gas tight manner, and said at least one discharge electrode includes an electrically conductive thermal isolator connected between said mesh body and said feed-through.
- 3. An electric lamp according to claim 2, wherein said lamp envelope defines a lamp axis and said mesh body is cylindrical and extends at least substantially parallel to said lamp axis.
- 4. An electric lamp according to claim 3, wherein said mesh body is circular cylindrical.
- 5. An electric lamp according to claim 3, wherein said conductive feed-through is a hollow cylindrical ferrule.
- 6. A low pressure discharge lamp, comprising:
- a tubular glass lamp envelope sealed in a gas tight manner and having opposing sealed end portions;
- an ionizable filling within said lamp envelope;
- at least a pair of discharge electrodes within said lamp envelope between which a gas discharge is maintained during lamp operation; each of said discharge electrodes being arranged at a said sealed end portion, at least one of said discharge electrodes including (i) a hollow cylindrical ferrule extending from outside the lamp envelope through the respective sealed end portion to the interior of the lamp envelope, (ii) an electrically conductive thermal isolator within said lamp envelope, connected to said ferrule, extending into the interior of said lamp envelope, and terminating at a distal end thereof, and (iii) a tip portion connected to said distal end of said thermal isolator, said tip portion comprising a mesh body and an electron emitter material carried by said mesh body,
- said ferrule, thermal isolator and tip portion each comprising one of (i) a refractory metal and (ii) a high temperature resistant alloy; and
- said electron emitter material being selected from a group comprising a mixed oxide of Ba, Sr and mixtures thereof with one or more of the metals from the series comprising Ta, Ti, Zr, Sc, Y, and La, said group excluding emitter materials of the composition Ba.sub.x Sr.sub.(1-x) Y.sub.2 O.sub.4, x being in the range of 0 to 1.
- 7. An electric lamp according to claim 6, wherein the emitter material is one or more mixed oxides selected from the group consisting of Ba.sub.4 Ta.sub.2 O.sub.9, Ba.sub.5 Ta.sub.4 O.sub.15, BaY.sub.2 O.sub.4, BaCeO.sub.3, Ba.sub..5 Sr.sub..5 Y.sub.2 O.sub.4, Ba.sub..75 Sr.sub..25 Y.sub.2 O.sub.4, Ba.sub.2 TiO.sub.4, BaZrO.sub.3, Ba.sub..5 Sr.sub..5 TiO.sub.3, and Ba.sub..5 Sr.sub..5 ZrO.sub.3.
- 8. An electric lamp according to claim 6, wherein said lamp envelope defines a lamp axis and said mesh is cylindrical and extends at least substantially parallel to said lamp axis.
- 9. An electric lamp according to claim 8, wherein said mesh is circular cylindrical.
- 10. An electric lamp according to claim 6, wherein said ionizable filling includes a rare gas and mercury.
- 11. An electric lamp according to claim 6, wherein said thermal isolator comprises at least one of (i) a metal wire and (ii) an integral elongate extension of said ferrule.
- 12. An electric lamp according to claim 6, wherein said ionizable filling comprises neon.
- 13. A narrow diameter low pressure discharge lamp, comprising:
- a tubular glass lamp envelope sealed in a gas tight manner and having opposing sealed end portions, said lamp having an internal diameter over the length thereof between said end portions of about 5 mm or less;
- an ionizable filling within said lamp envelope;
- a pair of discharge electrodes within said lamp envelope between which a gas discharge is maintained during lamp operation; each of said discharge electrodes being arranged at a respective sealed end portion, extending at least substantially parallel to the lamp axis, and including (i) a hollow cylindrical ferrule extending from outside the lamp envelope through the respective sealed end portion to the interior of the lamp envelope, (ii) an electrically conductive thermal isolator within said lamp envelope connected to said ferrule, extending into the interior of said lamp envelope and terminating at a distal end thereof, and (iii) a tip portion connected to said distal end of said thermal isolator, said tip portion comprising a mesh body and an electron emitter material carried by said mesh body,
- said ferrule, thermal isolator and tip portion each comprising one of (i) a refractory metal and (ii) a high temperature resistant alloy; and
- said electron emitter material being selected from the group comprising a mixed oxide of Ba, Sr and mixtures thereof with one or more of the metals from the series comprising Ta, Ti, Zr, Sc, Y, and La, said group excluding emitter materials of the composition Ba.sub.x Sr.sub.(1-x) Y.sub.2 O.sub.4, x being in the range of 0 to 1.
- 14. A narrow diameter low pressure discharge lamp according to claim 13, wherein said thermal isolator comprises a length of wire having one end connected to said ferrule and an opposing end connected to said mesh body.
- 15. A narrow diameter low pressure discharge lamp according to claim 13, wherein said thermal isolator comprises said ferrule having an integral elongate extension formed by removal of material from said ferrule, said elongate extension having an end carrying said mesh body.
- 16. A narrow diameter low pressure discharge lamp according to claim 13, wherein said ionizable filling includes a rare gas and mercury.
- 17. A narrow diameter low pressure discharge lamp according to claim 13, wherein said ionizable filling comprises neon.
- 18. A narrow diameter low pressure discharge lamp according to claim 13, wherein the emitter material is one or more mixed oxides selected from the group consisting of Ba.sub.4 Ta.sub.2 O.sub.9, Ba.sub.5 Ta.sub.4 O.sub.19, BaY.sub.2 O.sub.4, BaCeO.sub.3, Ba.sub.2 TiO.sub.4, BaZrO.sub.3, Ba.sub.x Sr.sub.1-x TiO.sub.3, and Ba.sub.x Sr.sub.1-x ZrO.sub.3, wherein x ranges from a value of 0 to 1.
- 19. A narrow diameter low pressure discharge lamp according to claim 13, wherein the emitter material is one or more mixed oxides selected from the group consisting of Ba.sub.4 Ta.sub.2 O.sub.9, BaY.sub.2 O.sub.4, BaCeO.sub.3, Ba.sub..5 Sr.sub..5 Y.sub.2 O.sub.4, Ba.sub..75 Sr.sub..25 Y.sub.2 O.sub.4, Ba.sub.2 TiO.sub.4, BaZrO.sub.3, Ba.sub..5 Sr.sub..5 TiO.sub.3, and Ba.sub..5 Sr.sub..5 ZrO.sub.3.
- 20. A narrow diameter low pressure discharge lamp according to claim 13, wherein said lamp envelope defines a lamp axis and said mesh is cylindrical and extends at least substantially parallel to said lamp axis.
CROSS-REFERENCE
This application is a continuation in part of U.S. application Ser. No. 08/581,236 filed Dec. 29, 1995 entitled "Hollow Electrodes For Low Pressure Discharge Lamps, Particularly Narrow Diameter Fluorescent and Neon Lamps and Lamps Containing The Same" of Vivek Mehrotra, Thomas McGee, Susan McGee and Jeorren Langevoort, which discloses and claims a gas discharge lamp with electrodes having a hollow tubular protrusion, of a heat resistant alloy or a refractory metal, and carrying an emitter material.
US Referenced Citations (15)
Foreign Referenced Citations (1)
Number |
Date |
Country |
0562679 |
Sep 1993 |
EPX |
Continuation in Parts (1)
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Number |
Date |
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Parent |
581236 |
Dec 1995 |
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