US 7,122,815 B2Granted

Infrared radiation emitter

OwnerDonald S. Woodinventor

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Abstract

An emitting source capable of radiating substantial energy in the near infrared spectrum and suitable for use in non-dispersive infrared gas analyzers or other devices is described. Operation can be steady state (DC) or pulsed at high frequency with excellent modulation characteristics. The device consists of a tungsten filament mounted across the pins of a small transistor outline header and centered at the focal point of a parabolic or other shaped reflector. The header assembly is enclosed by a resistance-welded cap and window assembly having a specially sealed sapphire or other suitable IR transmissive window. Fundamental to the operation of the inventive IR emitter is the incorporation of a getter within the header package configured to prevent oxidation degradation of the tungsten filament. An inert gas backfill limits filament evaporation and further extends apparatus lifetime.

Claims26

Dependent claims

An infrared radiation emitter, comprising:

a header having a base;
first and second input pins;
a reflector attached to said base and having a focal point and an optical axis;
a tungsten wire having ends, said tungsten wire suspended above said reflector;
leads electrically connecting said tungsten wire to said input pins;
a cap and window assembly attached to said base, said window assembly including a cap and an IR transmissive window hermetically sealed with a vacuum tight seal to said cap to form a sealed chamber, said cap and window assembly attached to said base such that said transmissive window is disposed above said tungsten wire and such that when electrical current is applied to said input pins, said tungsten wire emits infrared light, wherein the infrared light is gathered by said reflector and directed through said transmissive window along said optical axis;
an oxygen absorbing getter strip, which, when activated, evacuates oxygen from said sealed chamber and thereby prevents oxidation of said tungsten wire, said getter strip welded to at least one of said first and second input pins;
and
an inert gas backfill contained within said sealed chamber;
and a getter-activating filament electrically connected to one of said input pins and to said base and disposed so as to be in close physical proximity with said oxygen absorbing getter strip.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/857,140Filed 27 May 2004 · us provisional application
Priority: 27 May 2003
Published: US 2004/0238763 A12 Dec 2004
Granted: 17 Oct 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification13 codes

G01J 1/08
Details: arrangements of light sources specially adapted for photometry standard sources, also using luminescent or radioactive material
H01K 1/18
Details: mountings or supports for the incandescent body
H01K 1/26
Details: screens; Filters
H01K 1/28
Details: envelopes; Vessels