Stable high temperature heater system with tungsten heating layer
AssigneeHeetronix
InventorJames Parsons
Life of this patent
Estimating the term…
Abstract
A sensor system has an AlN substrate, a W layer on the substrate, a signal source adapted to apply an electrical actuating signal to the W layer, and a sensor adapted to sense the response of the W layer. The W layer can comprise a thin film, with various types of optional protective layers over the film. Applications include sensing temperature, fluid flow rates, fluid levels, pressure and chemical environments. For a planar heater, the W layer comprises a plurality of conductive strands distributed on the substrate, with the strands generally parallel and serpentine shaped for a rectangular substrate, and extending along respective lines of longitude that merge at opposite poles of the substrate for a circular substrate.
Claims40
A heater system, comprising:
- an AlN substrate,
- a W layer on said substrate,
- a signal source connected to apply a current or a voltage actuating signal to heat said W layer, and
- a sensor connected to sense the voltage across said W layer in the case of a current actuating signal, or the current through said W layer in the case of a voltage actuating signal, as an indication of the temperature of said W layer, said W layer having a resistance which varies with the W layer's temperature.
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A heater system, comprising:
- an AlN substrate,
- a conductive layer on said substrate which, over a predetermined temperature operating range, has an expansion coefficient within 1.00+/−0.07 of said substrate, is substantially non-reactive with said substrate, and exhibits substantially no solid-solubility or interdiffusivity with said substrate,
- a signal source connected to apply a current or a voltage actuating signal to heat said conductive layer, and
- a sensor connected to sense the voltage across said conductive layer in the case of a current actuating signal, or the current through said conductive layer in the case of a voltage actuating signal, as an indication of the temperature of said conductive layer, said conductive layer having a resistance which varies with the conductive layer's temperature.
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37-39. (canceled)
A heater system, comprising:
- an insulative substrate,
- a W conductive layer on said substrate which, over a predetermined temperature operating range, has an expansion coefficient within 1.00+/−0.07 of said substrate, is substantially non-reactive with said substrate, and exhibits substantially no solid-solubility or interdiffusivity with said substrate,
- a signal source connected to apply a current or a voltage actuating signal to heat said W layer, and
- a sensor connected to sense the voltage across said W layer in the case of a current actuating signal, or the current through said W layer in the case of a voltage actuating signal, as an indication of the temperature of said W layer, said W layer having a resistance which varies with the W layer's temperature.
47-50. (canceled)
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Dependencies are inferred from the claim text.