Discharge lamp with reflective jacket

• US 6,291,936 B1
• Filed: 11/25/1998
• Issued: 09/18/2001
• Est. Priority Date: 05/31/1996
• Status: Expired due to Fees

• Current Assignee: Fusion Lighting, Inc.
• Original Assignee: Fusion Lighting, Inc.
• Inventors: Turner, Brian P., MacLennan, Donald A., Kipling, Kent
• Primary Examiner(s): Lee, Benny T.
• Application Number:
  US09/147,309
• Time in Patent Office: 1,028 Days
• Field of Search: 315/39, 315/248
• US Class Current: 315/39
• CPC Class Codes: H01J 61/025 Associated optical elements
• CPC Class Codes: H01J 61/12 Selection of substances for gas fillings; Specified operating pressure or temperature
• 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 61/38 Devices for influencing the colour or wavelength of the light
• CPC Class Codes: H01J 65/044 the field being produced by a separate microwave unit

Abstract

A discharge lamp includes an envelope, a fill which emits light when excited disposed in the envelope, a source of excitation power coupled to the fill to excite the fill and cause the fill to emit light, and a reflector disposed around the envelope and defining an opening, the reflector being configured to reflect some of the light emitted by the fill back into the fill while allowing some light to exit through the opening. The reflector may be made from a material having a similar thermal index of expansion as compared to the envelope and which is closely spaced to the envelope. The envelope material may be quartz and the reflector material may be either silica or alumina. The reflector may be formed as a jacket having a rigid structure which does not adhere to the envelope. The lamp may further include an optical clement spaced from the envelope and configured to reflect an unwanted component of light which exited the envelope back into the envelope through the opening in the reflector. Light which can be beneficially recaptured includes selected wavelength regions, a selected polarization, and selected angular components.

Claims

1. A discharge lamp, comprising:

an envelope;

a fill which emits light when excited disposed in the envelope, the fill being capable of absorbing light and re-emitting the absorbed light, the light emitted from the fill having a first spectral power distribution in the absence of reflection of light back into the fill;

a reflector disposed around the envelope and defining an opening, the reflector being configured to reflect some of the light emitted by the fill back into the fill while allowing some light to exit through the opening, the exiting light having a second spectral power distribution different from the first spectral power distribution;

a source of excitation power coupled to the fill to excite the fill and cause the fill to emit light; and

an optical element spaced from the envelope and configured to reflect an unwanted component of light which exited the envelope back into the envelope through the opening in the reflector.

2. The lamp as recited in claim 1, wherein the fill is capable of recapturing the unwanted components of light and converting at least some of the recaptured light to useful light.

3. The lamp as recited in claim 1, wherein the optical element is further configured to pass other components of light.

4. The lamp as recited in claim 1, wherein the unwanted component of light comprises at least one of a selected wavelength region and a selected spatial orientation.

5. A discharge lamp, comprising:

an envelope;

a fill which emits light when excited disposed in the envelope,

a source of excitation power coupled to the fill to excite the fill and cause the fill to emit light; and

a reflector disposed around the envelope and defining an opening, the reflector being configured to reflect some of the light emitted by the fill back into the fill while allowing some light to exit through the opening,

wherein the reflector comprises a material having a similar thermal index of expansion as compared to the envelope and which is closely spaced to the envelope.

6. The lamp as recited in claim 5, wherein the reflector defines a diffusing orifice through which light exits the lamp.

7. The lamp as recited in claim 6, wherein the diffusing orifice comprises side walls which are tong enough to randomize light exiting from the diffusing orifice.

8. The lamp as recited in claim 5, wherein the reflector defines an aperture through which light exits the envelope, and further comprising:

a second reflector disposed adjacent the aperture and configured to recapture light which might otherwise be lost at an interface of the aperture.

9. The lamp as recited in claim 5, wherein the reflector contacts the envelope in one or more locations and otherwise is spaced from the envelope within about several thousandths of an inch.

10. The lamp as recited in claim 5, wherein the reflector material does not adhere to the envelope.

11. The lamp as recited in claim 5, wherein the reflector material is the same material as the envelope but with a different structure.

12. The lamp as recited in claim 11, wherein the envelope material is quartz and the reflector material includes silica.

13. The lamp as recited in claim 5, wherein the reflector comprises a container having walls spaced from the bulb and a reflecting powder is disposed in a gap between the container walls and the envelope.

14. The lamp as recited in claim 5, wherein the reflector comprises a jacket having a rigid structure.

15. The lamp as recited in claim 14, wherein the jacket comprises two ceramic shells integrally connected to each other.