Electrode-inlead for miniature discharge lamps

Claim 2

An electrode-inlead assembly comprising an electrode having a pin-like root end of refractory metal joined on axis to a fine refractory metal wire inlead having a foliated portion therein, the join being effected by a laser weld.

Claim 3

An electrode-inlead assembly as in claim 1 wherein the electrode is tungsten and the inlead is molybdenum.

Claim 4

An electrode-inlead assembly as in claim 1 wherein the distance from the laser weld to the beginning of the foliated portion does not exceed 2 millimeters.

Claim 5

An electrode inlead assembly as in claim 3 wherein said distance does not exceed 1 millimeter.

Claim 6

A miniature high pressure metal vapor discharge lamp comprising a thin-walled vitreous envelope defining a discharge space not exceeding approximately 1 cubic centimeter in volume and a pair of tungsten electrodes therein having pin-like root ends, said envelope having slender necks through which extend refractory metal inleads laser butt-welded to said electrode ends and including foliated portions hermetically sealed therein whereby to achieve minimum end losses.

Claim 7

A miniature high pressure metal vapor discharge lamp comprising a thin-walled vitreous envelope defining a discharge space not exceeding approximately 1 cubic centimeter in volume and a pair of tungsten electrodes therein having pin-like root ends, said envelope having slender necks through which extend refractory metal inleads laser butt-welded to said electrode ends and including foliated portions hermetically sealed therein whereby to achieve minimum end losses.

Claim 8

A miniature discharge lamp as in claim 5 wherein the distance between the laser butt weld and the start of the foliated portion does not exceed 2 millimeters.

Claim 9

A lamp as in claim 6 wherein said distance does not exceed 1 millimeter.

Claim 10

An electrode-inlead assembly comprising an electrode having a pin-like root end of tungsten joined on axis to a fine refractory metal wire inlead having means adapting it to make a seal through a fused silica part, the join being effected by a laser weld.

Claim 11

An electrode-inlead assembly comprising an electrode having a pin-like root end of tungsten joined on axis to a fine refractory metal wire inlead having means adapting it to make a seal through a fused silica part, the join being effected by a laser weld.

Claim 12

An electrode inlead assembly as in claim 8 wherein said means comprises a bead of glass formed around the refractory metal wire inlead with wetting of same, said glass having a coefficient of thermal expansion intermediate that of said refractory metal and that of fused silica.

Claim 13

An electrode-inlead assembly as in claim 9 wherein the inlead is molybdenum and the coefficient of thermal expansion of said glass is intermediate that of molybdenum and that of fused silica.

Claim 14

A miniature high pressure metal vapor discharge lamp comprising a thin-walled fused silica envelope having a bulb portion defining a discharge space not exceeding approximately 1 cubic centimeter in volume and a pair of tungsten electrodes therein having pin-like root ends, said envelope having slender necks through which extend refractory metal wire inleads laser butt-welded to said electrode ends, each of said inleads having a bead of glass formed around the wire with wetting of same, said glass having a coefficient of thermal expansion intermediate that of said refractory metal and that of fused silica, the neck being contracted around the inlead without wetting it substantially from the bulb portion to the glass bead and being contracted around and wetted by said glass bead in order to achieve a hermetic seal at that point.

Claim 15

A miniature high pressure metal vapor discharge lamp comprising a thin-walled fused silica envelope having a bulb portion defining a discharge space not exceeding approximately 1 cubic centimeter in volume and a pair of tungsten electrodes therein having pin-like root ends, said envelope having slender necks through which extend refractory metal wire inleads laser butt-welded to said electrode ends, each of said inleads having a bead of glass formed around the wire with wetting of same, said glass having a coefficient of thermal expansion intermediate that of said refractory metal and that of fused silica, the neck being contracted around the inlead without wetting it substantially from the bulb portion to the glass bead and being contracted around and wetted by said glass bead in order to achieve a hermetic seal at that point.