Electric heating – Heating devices – With power supply and voltage or current regulation or...
Patent
1996-10-11
1998-06-16
Paschall, Mark H.
Electric heating
Heating devices
With power supply and voltage or current regulation or...
219492, 219494, 219209, 359 44, 359 86, H05B 102
Patent
active
057674892
ABSTRACT:
Resolution of liquid crystal microthermographic measurements are improved by depositing a layer of organic pretreatment on the surface of a semiconductor device. A layer of thermographically sensitive liquid crystal material is then deposited on the organic pretreatment layer so that a controlled liquid crystal material layer thickness and an orientation of a majority of crystal molecules of the liquid crystal material parallel to the surface is achieved. The nominal temperature of the surface to be measured is controlled by sensing the nominal temperature near the surface, converting the sensed temperature to a current temperature sense signal, comparing the current temperature sense signal to a target temperature value, and activating a heater in thermal communication with the surface when the current temperature sense signal varies from the reference signal magnitude. A state of essential thermal equilibrium is maintained at and near the surface by thermally insulating the surface and a volume adjacent the surface.
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Hewlett--Packard Company
Jenski Raymond A.
Paschall Mark H.
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