Thin film ceramic thermocouples

Abstract

A thin film ceramic thermocouple ( 10 ) having two ceramic thermocouple ( 12, 14 ) that are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma. Since each element is prepared under different plasma conditions, they have different electrical conductivity and different charge carrier concentration. The thin film thermocouple ( 10 ) can be transparent. A versatile ceramic sensor system having an RTD heat flux sensor can be combined with a thermocouple and a strain sensor to yield a multifunctional ceramic sensor array. The transparent ceramic temperature sensor that could ultimately be used for calibration of optical sensors.

1 . A ceramic thermocouple, said thermocouple comprising: 
 a substrate;    a first ceramic thermoelement formed on a substrate; and    a second ceramic thermoelement formed on a substrate, each element having a different composition such that the first and second thermoelements are in contact with each other in at least on point to form a junction, and wherein each element was prepared in a different oxygen/nitrogen/argon plasma.    
   
   
       2 . The ceramic thermocouple of  claim 1 , wherein each ceramic thermoelement has a different electrical conductivity and different charge carrier concentration.  
   
   
       3 . The thermocouple of  claim 1 , wherein the charge carrier concentration in each element is controlled by the nitrogen and oxygen partial pressures in the plasma from which said thermoelements were prepared.  
   
   
       4 . The thermocouple of  claim 1 , wherein the thermocouple is transparent in the visible spectrum.  
   
   
       5 . The thermocouple of  claim 1 , wherein the thermocouple may operate at a temperature of greater than 1500° C. for an extended period of time.  
   
   
       6 . The thermocouple of  claim 1 , wherein each ceramic thermoelement is formed in plasma containing 10 mtorr or less of nitrogen, 0-10 mtorr of argon and 0-10 mtorr of oxygen.  
   
   
       7 . The thermocouple of  claim 1 , wherein the substrates are electrically insulating.  
   
   
       8 . A ceramic sensor, said sensor comprising a ceramic thermocouple comprising a substrate; 
 a first ceramic thermoelement, a second ceramic thermoelement, each element prepared in a different oxygen/nitrogen/argon plasma, and fabricated in an immediate vicinity of a ceramic strain gauge having the composition of either the first or second thermoelements, wherein the strain gauge is formed simultaneously of either the first or second thermoelement.    
   
   
       9 . The ceramic thermocouple of  claim 1 , wherein each ceramic thermoelement is one of the following oxides or mixture thereof, including at least one of indium oxide, antimony oxide, tin oxide and aluminum-doped zinc oxide.  
   
   
       10 . A method of preparing a thin film ceramic thermocouple, said method comprises: 
 providing a substrate;    depositing indium-tin-oxide onto said substrate in a plasma of argon, nitrogen and oxygen;    depositing indium-tin-oxide onto said substrate to form a second ceramic thermocouple element in a different oxygen/nitrogen/argon plasma than the first ceramic thermoelement such that the two elements have different charge carrier concentrations;    coupling the two elements to form a thin film ceramic thermocouple.    
   
   
       11 . The method of  claim 10 , wherein the plasma contains 10 mtorr or less of nitrogen, 0-10 mtorr of argon and 0-10 mtorr of oxygen.