Apparatus and method for eliminating microcracks in alumina ceramic discharge devices

Claim 1

A ceramic discharge lamp comprising an elongated outer vitreous envelope sealed to a metallic base, a pair of lead-in conductors connected to said base and extending into said envelope; an arc tube mounting frame connected to onE of said lead-in conductors and extending within said envelope for a substantial portion of the length thereof, an alumina ceramic arc tube containing a discharge sustaining fill including sodium mounted axially within the said outer envelope between the other of said lead-in conductors and said frame, said frame being stainless steel and having a chrome oxide coating formed on the surface thereof.

Claim 5

The method of improving the performance of a high intensity discharge device adapted to be operated from an AC potential source and comprising an elongated alumina arc tube having electrodes operatively sealed therein proximate the ends thereof and enclosing a discharge sustaining filling comprising inert gas, sodium and mercury, said arc tube being supported within an outer envelope by supporting frame means comprising at least one elongated lead-in conductor spaced from said arc tube and longitudinally extending substantially the entire length of said arc tube, and a short lead-in conductor positioned substantially at an end of said outer enveloped, said lead-in conductors being connected to said electrodes of said device, and said outer envelope enclosing a vacuum which method comprises: a. making all components of said supporting frame means which are exposed to the intense radiation as generated within said arc tube, when operated, substantially non-photo-electron emissive under bombardment of such radiations, and electrically connecting to said short lead-in conductor an additional conductor which is non-photo-electron emissive when exposed to said intense radiations, and supporting said additional conductor in receptive proximity to said arc tube to intercept and neutralize any photo-electrons which might be generated from the radiation of said elongated lead-in conductor and any supporting members associated therewith when said elongated lead-in conductor carries a negative half cycle for the AC potential use to energize said device.

Claim 6

The method of improving the performance of a high intensity discharge device adapted to be operated from an AC potential source and comprising an elongated alumina arc tube having electrodes operatively sealed therein proximate the ends thereof and enclosing a discharge sustaining filling comprising inert gas, sodium and mercury, said arc tube being supported within an outer envelope by supporting frame means comprising at least one elongated lead-in conductor spaced from said arc tube and longitudinally extending substantially the entire length of said arc tube, and a short lead-in conductor positioned substantially at an end of said outer enveloped, said lead-in conductors being connected to said electrodes of said device, and said outer envelope enclosing a vacuum which method comprises: a. making all components of said supporting frame means which are exposed to the intense radiation as generated within said arc tube, when operated, substantially non-photo-electron emissive under bombardment of such radiations, and electrically connecting to said short lead-in conductor an additional conductor which is non-photo-electron emissive when exposed to said intense radiations, and supporting said additional conductor in receptive proximity to said arc tube to intercept and neutralize any photo-electrons which might be generated from the radiation of said elongated lead-in conductor and any supporting members associated therewith when said elongated lead-in conductor carries a negative half cycle for the AC potential use to energize said device.

Claim 7

The method of improving the performance of a high intensity discharge device adapted to be operated from an AC potential source, which discharge device includes an elongated alumina arc tube having electrodes operatively sealed therein proximate the ends thereof and enclosing a discharge sustaining fill including sodium, said arc tube being supported within an outer envelope by a supporting frame, said supporting frame being spaced from said arc tube and extending longitudinally substantially the entire length of said outer envelope, and a short lead-in conductor, said lead-in conductors connected to said electrodes of said device, and said outer envelope enclosing a vacuum, which method comprises: a. interposing a non-photo-electron emissive metallic member between said arc tube and said elongated lead-in conductor and b. electrically connecting said non-photo-electron emissive metallic member to said short lead-in conductor to thereby intercept and neutralize any photoelectrons which might be generated from the irradiation of said elongated lead-in conductor and associated supporting members with said non-photo-electron emissive metallic member being, during operation, always of the same electrical potential as said short lead-in conductor and of the opposite electrical potential of said elongated lead-in conductor.

Claim 8

The method of improving the performance of a high intensity discharge device adapted to be operated from an AC potential source, which discharge device includes an elongated alumina arc tube having electrodes operatively sealed therein proximate the ends thereof and enclosing a discharge sustaining fill including sodium, said arc tube being supported within an outer envelope by a supporting frame, said supporting frame being spaced from said arc tube and extending longitudinally substantially the entire length of said outer envelope, and a short lead-in conductor, said lead-in conductors connected to said electrodes of said device, and said outer envelope enclosing a vacuum, which method comprises: a. interposing a non-photo-electron emissive metallic member between said arc tube and said elongated lead-in conductor and b. electrically connecting said non-photo-electron emissive metallic member to said short lead-in conductor to thereby intercept and neutralize any photoelectrons which might be generated from the irradiation of said elongated lead-in conductor and associated supporting members with said non-photo-electron emissive metallic member being, during operation, always of the same electrical potential as said short lead-in conductor and of the opposite electrical potential of said elongated lead-in conductor.