Sealed beam lamps

• US 4,677,343 A
• Filed: 11/16/1984
• Issued: 06/30/1987
• Est. Priority Date: 11/18/1983
• Status: Expired due to Fees

• Current Assignee: Thorn EMI Plc (Universal Music Group NV)
• Original Assignee: Thorn EMI Plc (Universal Music Group NV)
• Inventors: Hick, Kevin
• Primary Examiner(s): Moore, David K.
• Assistant Examiner(s): Razavi, Michael
• Application Number:
  US06/671,947
• Time in Patent Office: 956 Days
• Field of Search: 315/61, 315/59, 315/60, 315/335, 315/336, 315/330, 315/263, 315/73, 315/74
• US Class Current: 315/61
• CPC Class Codes: H01J 61/045 Thermic screens or reflectors heat-reflecting coatings on the wall of the vessel H01J61/35
• CPC Class Codes: H01J 61/547 using an auxiliary electrode outside the vessel H01J61/544 takes precedence

Abstract

A discharge lamp is provided with a starting aid in the form of a loop of conductive wire arranged around the discharge lamp arc tube and a novel spark gap. A conductive element is electrically connected between the loop and an insulating sleeve adapted to form a spark gap by means of the conductive element wrapped around an opening in the insulating sleeve. The opening can be in the form of a drilled hole or slot and the arrangement is particularly useful in the restricted confines of a sealed beam reflector lamp.

Claims

1. A discharge lamp comprising an outer envelope, an arc tube disposed within the envelope in spaced relationship thereto and having electrodes for sustaining a discharge therebetween, electrical in-leads extending continuously between electrical conductors sealed to said envelope and respective electrodes, the lamp including a starting aid and a spark gap, the spark gap being supported by one of said in-leads and being arranged for electrical connection between one of the in-leads and the starting aid by an electrically conductive element wherein the spark gap comprises a predetermined length of insulating material forming a sleeve placed around said one of the in-leads, the sleeve serving to space the conductive element from the in-lead and define an opening to provide said spark gap.

10. A discharge lamp according to claim 1 wherein the discharge lamp comprises a sealed beam lamp including a reflector bowl and wherein the in-leads serve also to support the arc tube in spaced relationship to the reflector bowl.

11. A discharge lamp according to claim 1 wherein the conductive element includes conductive tape wrapped around the insulating sleeve and extending outwards of the end face of the sleeve.

2. A sealed beam lamp comprising an outer envelope including a reflector bowl, a single ended discharge arc tube disposed within the outer envelope in spaced relationship thereto having electrodes for sustaining a discharge therebetween, electrical in-leads extending continuously from the outer envelope to respective electrodes and annular sleeves of insulating material placed around the in-leads adjacent the bowl the lamp including a starting aid and a spark gap, the spark gap being supported by one of said in-leads and being arranged for electrical connection to one of said in-leads and the starting aid by an electrically conductive element wherein the sleeve of said in-lead associated with said conductive element forms a spacer between the conductive element and said in-lead and defines an opening thereby providing said spark gap.

3. A sealed beam lamp according to claim 2 wherein an opening is formed in the insulating sleeve.

4. A sealed beam lamp according to claim 3 wherein the opening defines a hole formed in the wall of the sleeve.

5. A sealed beam lamp according to claim 3 wherein the opening defines a longitudinal slot.

6. A sealed beam lamp according to claim 3 wherein the conductive element includes conductive tape wrapped around the insulating sleeve to cover the opening.

7. A sealed beam lamp according to claim 2 wherein the conductive element includes conductive tape wrapped around one of the insulating sleeves and extending outwards of the end face of the sleeve.

8. A sealed beam lamp according to claim 2 wherein the in-leads serve also to support the arc tube in spaced relationship to the reflector bowl.

9. A sealed beam lamp according to claim 2 wherein the sleeve is joined to an annular shield thereby forming an integrated spark gap and heat shield, the sleeve and the shield being made of ceramic material.