Polymer thick film heating element on a glass substrate

An apparatus for heating a substrate, said apparatus comprising:

• a substrate having a surface, said substrate being a glass material;
• a first conductor adhered to said surface, said first conductor being formed from a first conductive polymer thick film ink;
• a second conductor adhered to said surface, said second conductor being formed from a second conductive polymer thick film ink;
• a resistive film in contact with said surface, said resistive film being formed from a first polymer thick film carbon ink having a specified conductivity, said resistive film in electrical contact with said first conductor, said resistive film in electrical contact with said second conductor, said resistive film including a plurality of strips, each of said plurality of strips extending from said first conductor to said second conductor, each of said plurality of strips in a spaced apart configuration;
• and
• a temperature sensor attached to said substrate, said temperature sensor being a thermistor.

An apparatus for heating a substrate, said apparatus comprising:

• a substrate having a surface, said substrate being a glass material;
• a means for heating said substrate;
• a means for sensing a temperature of said substrate;
• a means for controlling said means for heating;
• and
• a means for connecting said means for controlling to an electrical power supply.

A method of heating a substrate with a resistance heater printed on the substrate, said method comprising the steps of:

• (a) applying a conductive polymer thick film ink to a first selected portion of a surface of a glass substrate wherein said first selected portion includes two areas that are electrically insulated from each other;
• (b) applying a resistive polymer thick film ink to a second selected portion of said surface, wherein said resistive polymer thick film ink is in contact with each of said two areas;
• (c) applying a first voltage to a controller mounted on said glass substrate;
• (d) measuring a temperature of said glass substrate with a surface mounted sensor;
• and
• (e) controlling said first voltage to produce a second voltage applied to said resistive polymer thick film ink and to maintain a selected temperature.