Two-wire layered heater system

Abstract

A heater system includes a substrate, a layered heater having a resistive layer formed on the substrate by a layered process, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor. A single set of electrical leads having two electrical lead wires provides power to the resistive layer and receives a signal indicative of a temperature of the resistive layer. A two-wire controller includes a power controller, and the two-wire controller is configured to receive the signal indicative of the temperature of the resistive layer, determine the temperature of the resistive layer, and control temperature of the heater system.

What is claimed is: 
     
         1 . An apparatus comprising:
 a resistive layer formed by a layered process selected from the group consisting of thick film, thin film, thermal spray, and sol-gel;   a two-wire controller comprising a power controller; and   a single set of electrical leads consisting of only two electrical lead wires connecting the resistive layer to the two-wire controller,   wherein the resistive layer has sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a sensor, and the resistive layer is in communication with the two-wire controller through the single set of electrical leads, wherein temperature information of the layered heater is provided on command from the resistive layer to the two-wire controller through the single set of electrical leads and the power controller supplies a power directly to the resistive layer to control the temperature of the resistive layer through the single set of electrical leads, wherein the two wire controller includes only a single set of electrical leads consisting of only two electrical lead wires connecting the two wire controller to the resistive layer.   
     
     
         2 . The heater system of  claim 1 , wherein the layered process is selected from the group consisting of thick film, thin film, thermal spray, and sol-gel. 
     
     
         3 . The heater system of  claim 1 , wherein the two-wire controller comprises a DC bias control for calculation of the resistance of the resistive layer. 
     
     
         4 . The heater system of  claim 1 , wherein the two-wire controller comprises an AC bias control for calculation of the resistance of the resistive layer. 
     
     
         5 . The heater system of  claim 1 , wherein the two-wire controller comprises high conduction angle firing. 
     
     
         6 . The heater system of  claim 1 , wherein the two-wire controller further comprises firmware. 
     
     
         7 . The apparatus according to  claim 1  further comprising a substrate, wherein the resistive layer is formed on the substrate. 
     
     
         8 . The apparatus according to  claim 1  further comprising a dielectric layer, wherein the resistive layer is formed on the dielectric layer. 
     
     
         9 . The apparatus according to  claim 1  wherein the two-wire controller further comprises a shunt resistor and temperature information of the layered heater is provided on command from the resistive layer to the two-wire controller through the single set of electrical leads by an output voltage, and the shunt resistor measures the change in current through the output voltage. 
     
     
         10 . The apparatus according to  claim 1 , wherein the sensor is a temperature sensor. 
     
     
         11 . An apparatus comprising:
 a resistive layer formed by a layered process selected from the group consisting of thick film, thin film, thermal spray, and sol-gel;   a single set of electrical leads consisting of only two electrical lead wires connecting the resistive layer to a two-wire controller including a power controller,   wherein the resistive layer has sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a sensor, and the resistive layer is in communication with the two-wire controller through the single set of electrical leads, wherein temperature information of the layered heater is provided on command from the resistive layer to the two-wire controller through the single set of electrical leads, and the power controller supplies a power directly to the resistive layer to control the temperature of the resistive layer through the single set of electrical leads, wherein the two wire controller includes only a single set of electrical leads consisting of only two electrical lead wires connecting the two wire controller to the resistive layer.   
     
     
         12 . The heater system of  claim 11 , wherein the two-wire controller comprises high conduction angle firing. 
     
     
         13 . The heater system of  claim 11 , wherein the two-wire controller comprises a shunt resistor for calculation of the resistance of the resistive layer. 
     
     
         14 . The heater system of  claim 11 , wherein the two-wire controller further comprises a microprocessor. 
     
     
         15 . The heater system of  claim 11 , wherein the two-wire controller further comprises firmware. 
     
     
         16 . The apparatus according to  claim 11  further comprising a substrate, wherein the resistive layer is formed on the substrate. 
     
     
         17 . The apparatus according to  claim 11  further comprising a dielectric layer, wherein the resistive layer is formed on the dielectric layer. 
     
     
         18 . The apparatus according to  claim 11  further comprising a substrate, wherein the dielectric layer is formed on the substrate. 
     
     
         19 . The apparatus according to  claim 11 , wherein the two-wire controller further comprises at least one of a DC bias control and an AC bias control for calculation of the resistance of the resistive layer, and temperature information of the layered heater is provided on command from the resistive layer to the two-wire controller through the single set of electrical leads by an output voltage, and the at least one of the DC bias control and the AC bias control determines temperature of the resistive layer using the output voltage from the resistance layer. 
     
     
         20 . A layered heater comprising:
 a substrate;   a resistive layer disposed on the substrate, the resistive layer having sufficient temperature coefficient of resistance characteristics such that the resistive layer is a heater element and a temperature sensor;   a protective layer disposed over the resistive layer;   a single set of electrical leads consisting of only two electrical lead wires connected to the resistive layer; and   a two-wire controller including a power controller and a microprocessor and connected to the resistive layer through the single set of electrical leads, wherein temperature information of the layered heater is provided on command from the resistive layer to the two-wire controller through the single set of electrical leads by an output voltage, the two-wire controller determines the temperature of the layered heater using the resistance of the resistive layer with the microprocessor, and the power controller supplies a power directly to the resistive layer to control the temperature of the layered heater through the single set of electrical leads, wherein the two wire controller includes only a single set of electrical leads consisting of only two electrical lead wires connecting the two wire controller to the resistive layer.