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US 5,499,597 AGranted
Optical temperature indicator using thermochromic semiconductors
OwnerJames W. Kronberginventor
Life of this patent
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Abstract
A reversible optical temperature indicator utilizes thermochromic semiconductors which vary in color in response to various temperature levels. The thermochromic material is enclosed in an enamel which provides protection and prevents breakdown at higher temperatures. Cadmium sulfide is the preferred semiconductor material. The indicator may be utilized as a sign or in a striped arrangement to clearly provide a warning to a user. The various color responses provide multiple levels of alarm.
Claims18
An optical temperature indicator comprising:
- a thermochromic semiconductor material;
- said thermochromic semiconductor material being contained within a first vitreous enamel and coated as indicia on a sign so that increased temperature causes the thermochromic semiconductor material to reversibly change color in response to variations in temperature to provide a warning;
- a second vitreous enamel;
- said second vitreous enamel surrounding said indicia and covering the other surfaces of the sign;
- said second vitreous enamel having a color which does not change significantly in response to temperature.
2 more elements
An optical temperature indicator comprising:
- a thermochromic semiconductor material defined by the formula Zn.sub.x Cd.sub.y Hg.sub.(1-x-y) O.sub.a S.sub.b Se.sub.c Te.sub.(1-a-b-c) where Zn represents zinc, Cd represents Cadmium, Hg represents mercury, O represents oxygen, S represents sulfur, Se represents selenium and Te represents tellurium;
- and the value of x is from 0.0 to 0.5, the value of y is from 0.5 to 1.0, the value of a is from 0.0 to 0.5, the value of b is from 0.5 to 1.0 and the value of c is from 0.0 to 0.5;
- said thermochromic semiconductor material being contained within a first vitreous enamel and coated as indicia on a surface so that increased temperature causes the thermochromic semiconductor material to reversibly change color in response to variations in temperature to provide a warning;
- a second vitreous enamel surrounding said indicia and covering other portions of the surface;
- said second vitreous enamel having a color which does not change significantly in response to temperature.
2 more elements
An optical temperature indicator comprising:
- a thermochromic semiconductor material defined by the formula Hg.sub.x Cd.sub.y Zn.sub.(1-x-y) S.sub.b Se.sub.(1-b) where Hg represents mercury, Cd represents Cadmium, Zn represents zinc, S represents sulfur and Se represents selenium;
- and the value of x ranges from 0.0 to 1.0, the value of y ranges from 0.0 to 1.0 and the value of b ranges from 0.5 to 1.0;
- said thermochromic semiconductor material being contained within a first vitreous enamel and coated as letters on a sign such that increased temperature causes the thermochromic semiconductor material to reversibly change color in response to variations in temperature to provide a graded warning;
- a second vitreous enamel comprising oxides of lead and antimony, said second vitreous enamel surrounding said letters and covering other portions of the sign;
- said second vitreous enamel having a color which does not change significantly in response to temperature;
- said letters being yellow at room temperature;
- said letters being orange at a first temperature above room temperature;
- said letters being red at a second temperature which is greater than said first temperature;
- said letters being black at a third temperature which is greater than said second temperature;
- and
- said colors providing a graded warning upon said sign, with levels of danger depending on the color which the letters display.
8 more elements
Dependencies are inferred from the claim text.