Wavelength filtering coating for high temperature lamps

• US 7,772,749 B2
• Filed: 05/01/2007
• Issued: 08/10/2010
• Est. Priority Date: 05/01/2007
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Ellis, Philip, Aurongzeb, Deeder
• Primary Examiner(s): MACCHIAROLO, PETER J
• Application Number:
  US11/799,430
• Publication Number:
  US 20080272682A1
• Time in Patent Office: 1,197 Days
• Field of Search: 313/112, 313/580, 359/350, 359/885
• US Class Current: 313/112
• CPC Class Codes: C03C 17/004 Coating the inside
• CPC Class Codes: C03C 17/225 Nitrides
• CPC Class Codes: C03C 17/23 Oxides C03C17/02 takes precedence
• CPC Class Codes: C03C 2217/23 Mixtures
• CPC Class Codes: C03C 2217/231 In2O3/SnO2
• CPC Class Codes: C03C 2217/24 Doped oxides
• CPC Class Codes: C03C 2217/281 Nitrides
• CPC Class Codes: C04B 35/115 Translucent or transparent products
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4529 applied from the gas phase
• CPC Class Codes: C04B 41/457 Non-superficial impregnation or infiltration of the substrate
• CPC Class Codes: C04B 41/5027 Oxide ceramics in general; Specific oxide ceramics not covered by C04B41/5029 - C04B41/5051
• CPC Class Codes: C04B 41/5031 Alumina
• CPC Class Codes: C04B 41/5049 Zinc or bismuth oxides
• CPC Class Codes: C04B 41/505 Tin oxide
• CPC Class Codes: C04B 41/87 Ceramics
• 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

Abstract

The invention relates to a discharge lamp having a thin film indium oxide coating on the interior lamp envelope surface that effectively reflects UV, near IR and microwave radiation while transmitting light in the visible spectrum, the lamp being a high temperature operating lamp.

Claims

1. A lamp comprising:

an envelope; and

a source of light energy enclosed therein;

wherein the envelope is a quartz or ceramic glass envelope, and bears a coating on the interior surface thereof, the coating comprising;

indium oxide, silicon, nitrogen, and at least one of tin oxide or zinc oxide; and

the coating exhibiting an initial crystal size at deposition of about 20 nm, and after exposure to a high temperature operating condition, exhibiting a crystal size of up to about 50 nm;

the coating operable to reflect UV and microwave light energy from the source of light energy back into the interior of the lamp and transmit visible light energy;

wherein the lamp is operable at said high temperatures of at least about 1150°

C.

2. The lamp of claim 1 wherein the envelope is quartz and the coating comprises at least:

from about 0.01 atomic weight percent up to about 45.0 atomic weight percent indium; and

from about 0.01 atomic weight percent up to about 31.0 atomic weight percent tin.

3. The lamp of claim 2 wherein the coating comprises In_1.8Sn_0.2O₃.

4. The lamp of claim 2 wherein the coating further comprises at least one of:

from about 0.01 atomic weight percent up to about 42.0 atomic weight percent nitrogen;

from about 0.01 atomic weight percent up to about 48.0 atomic weight percent silicon; and

from about 25.0 atomic weight percent to about 85.0 atomic weight percent oxygen.

5. The lamp of claim 4 wherein the coating comprises 11.57% nitrogen, 55.02% oxygen, 17.72% silicon, 14.93% indium, and 0.76% tin, wherein all percentages are atomic weight percentages.

6. The lamp of claim 1 wherein the coating is deposited in a single layer.

7. The lamp of claim 1 wherein the coating is deposited in multiple layers.

8. The lamp of claim 7 wherein the multiple layers have the same composition.

9. The lamp of claim 7 wherein at least two of the multiple layers have different compositions.

10. The lamp of claim 1 wherein the envelope is ceramic and the coating comprises at least molybdenum, indium oxide, zinc oxide and aluminum.

11. The lamp of claim 1 wherein the coating as deposited functions to filter the transmission of light energy such that:

less than 10% of ultraviolet light energy is transmitted;

up to 99% of visible light energy at from about 400 nm to about 700 nm is transmitted; and

less than 25% of microwave light energy is transmitted.

12. The lamp of claim 1 wherein after anneal at 600°

C. for about 24 hours the coating functions to filter the transmission of light energy such that;

less than 1% of ultraviolet light energy is transmitted;

up to 99% of visible light energy at from about 400 nm to about 700 nm is transmitted;

less than about 50% of near infrared light energy is transmitted; and

less than 10% of microwave light energy is transmitted.