High-pressure discharge lamp

• US 20060049764A1
• Filed: 08/25/2005
• Published: 03/09/2006
• Est. Priority Date: 09/07/2004
• Status: Active Grant

• Current Assignee: OSRAM GmbH (Ams-Osram AG)
• Original Assignee: OSRAM GmbH (Ams-Osram AG)
• Inventors: Reiners, Thomas, Bedynek, Florian, Grundmann, Dirk, Bonigk, Michael, Schimke, Conrad
• Granted Patent: US 7,705,540 B2
• Time in Patent Office: Days
• US Class Current: 313/637
• 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

Abstract

The invention relates to a high-pressure discharge lamp having a transparent discharge vessel, an ionizable filling which is arranged in the discharge space of the discharge vessel and electrodes, which extend into the discharge space of the discharge vessel, for the purpose of producing a gas discharge, as well as power supply lines, which are passed out of the discharge vessel, for the purpose of supplying energy to the electrodes, the discharge vessel of the high-pressure discharge lamp being provided partially with an electrically conductive coating, with the result that a capacitive coupling is produced between the coating and at least one electrode and/or power supply line. As a result, the starting properties and the luminous efficiency of the lamp are improved.

Claims

1. A high-pressure discharge lamp having a transparent discharge vessel, an ionizable filling which is arranged in the discharge space of the discharge vessel and electrodes, which extend into the discharge space of the discharge vessel, for the purpose of producing a gas discharge, as well as power supply lines, which are passed out of the discharge vessel, for the purpose of supplying energy to the electrodes, the high-pressure discharge lamp having an electrically conductive, transparent layer, wherein said electrically conductive, transparent layer is in the form of an at least partial coating of the surface of the discharge vessel, with the result that a capacitive coupling is produced between the coating and at least one electrode and/or power supply line.

2. The high-pressure discharge lamp as claimed in claim 1, wherein the coating is arranged on the outer surface of the discharge vessel.

3. The high-pressure discharge lamp as claimed in claim 1 or 2, wherein the coating is arranged at least in the region of the discharge space and extends over part of the circumference of the discharge space.

4. The high-pressure discharge lamp as claimed in claim 1 which is envisaged for operation in the horizontal position, with electrodes arranged on a horizontal plane, wherein the surface region of the discharge vessel which is provided with said coating is arranged beneath the electrodes.

5. The high-pressure discharge lamp as claimed in claim 1 which is provided with a base at one end, wherein the discharge vessel has a sealed end near to the base and a sealed end remote from the base, in each case a power supply line for the electrodes being passed out of said ends, the power supply line which is passed out of that end of the discharge vessel which is remote from the base being connected to a power return line which is passed back to the base, and said coating being arranged on a surface region of the discharge vessel which faces said power return line.

6. The high-pressure discharge lamp as claimed in claim 5, wherein said coating is delimited on a surface region of the discharge vessel which is arranged between the power return line and the connecting axis of the electrodes and extends in the longitudinal direction of the lamp at least over part of the discharge space and part of one of the two ends of the discharge vessel.

7. The high-pressure discharge lamp as claimed in one of claims 1, 5 or 6, wherein said at least one power supply line comprises at least one molybdenum foil embedded in the material of the discharge vessel, and said coating extends up to the at least one molybdenum foil, the at least one molybdenum foil being oriented such that one of its two sides faces the coating.

8. The high-pressure discharge lamp as claimed in claim 1, wherein said coating is made from doped tin oxide.

9. The high-pressure discharge lamp as claimed in claim 1, wherein the resistance of said coating measured between two points of the coating arranged at a distance of 1 cm from one another is in the range of order of magnitude of 10³ ohms to 10⁵ ohms.

10. The high-pressure discharge lamp as claimed in claim 1, wherein the high-pressure discharge lamp is provided with a transparent outer bulb which surrounds at least the discharge space of the discharge vessel.

11. The high-pressure discharge lamp as claimed in claim 10, wherein the intermediate space between the outer bulb and the discharge vessel is provided with a gas filling which has a coldfilling pressure in the range from 5 kPa to 150 kPa.

12. The high-pressure discharge lamp as claimed in claim 11, wherein said gas filling contains nitrogen or at least one noble gas.

13. The high-pressure discharge lamp as claimed in claim 12, wherein said gas filling also contains oxygen.