Electrical resistor material, resistor made therefrom and method of making the same

Claim 1

An electrical resistor of resistivity of less than 600 ohms per square comprising a substrate, the substrate being electrically insulating, and a layer of resistor material having a thickness of less than about 1.0 mil on a surface of the substrate, the resistor material comprising from about 25 to about 35% by weight glass and from about 50 to about 75% by weight conductive particles, the conductive particles comprising tin oxide and ruthenium containing material in an amount of at least about 0.2% by weight, expressed as RuO 2 , the mass ratio of ruthenium containing material, as RuO 2 , to tin oxide being less than about 7:93, the glass having a melting point below the melting point of tin oxide.

Claim 27

A method of preparing an electrical resistor providing a resistivity of less than 600 ohms per square comprising the steps of: (a) coating a surface of an electrically insulating substrate with a mixture comprising from about 25 to about 35% by weight glass frit and from about 50 to about 75% by weight conductive particles, the conductive particles comprising tin oxide and ruthenium containing material, the ruthenium containing material, expressed as RuO 2 , being present in an amount of at at least about 0.2% by weight of the conductive particles, the mass ratio of the ruthenium containing material, as RuO 2 , to tin oxide being less than about 7:93, wherein the mixture is coated onto the substrate in a thickness of less than about 1.0 mil; (b) firing the coated substrate in a substantially non-oxidizing atmosphere to a temperature between about 850° C. and about 1050° C. at which the glass frit softens but the tin oxide does not melt; and (c) cooling the coated substrate to form a layer of glass bonded to the substrate and having the conductive particles dispersed throughout the glass, wherein the electrical resistor has a resistivity of less than about 600 ohms per square.

Claim 28

A method of preparing an electrical resistor providing a resistivity of less than 600 ohms per square comprising the steps of: (a) coating a surface of an electrically insulating substrate with a mixture comprising from about 25 to about 35% by weight glass frit and from about 50 to about 75% by weight conductive particles, the conductive particles comprising tin oxide and ruthenium containing material, the ruthenium containing material, expressed as RuO 2 , being present in an amount of at at least about 0.2% by weight of the conductive particles, the mass ratio of the ruthenium containing material, as RuO 2 , to tin oxide being less than about 7:93, wherein the mixture is coated onto the substrate in a thickness of less than about 1.0 mil; (b) firing the coated substrate in a substantially non-oxidizing atmosphere to a temperature between about 850° C. and about 1050° C. at which the glass frit softens but the tin oxide does not melt; and (c) cooling the coated substrate to form a layer of glass bonded to the substrate and having the conductive particles dispersed throughout the glass, wherein the electrical resistor has a resistivity of less than about 600 ohms per square.

Claim 39

A method for preparing an electrical resistor providing a resistivity of less than about 600 ohms per square and a temperature coefficient of resistance within ±150 ppm/°C. comprising the steps of: (a) placing termination comprising copper on an electrically insulating substrate; (b) coating a surface of the substrate with a mixture comprising from about 25 to about 35% by weight glass frit, from about 50 to about 75% by weight conductive particles, and at least 0.1% by weight of an oxide of manganese, the conductive particles consisting essentially of from about 97 to about 99% by weight tin oxide and from about 1% to about 3% by weight ruthenium oxide, the mixture being in contact with the terminations and being applied in a thickness of less than about 1.0 mil; (c) firing the coated substrate in a substantially non-oxidizing atmosphere to a temperature between about 350° and about 1050° C. at which the glass frit softens but the tin oxide does not melt; and (d) cooling the coated substrate to form a layer of glass bonded to the substrate and having the conductive particles dispersed throughout the glass, wherein the electrical resistor has a resistivity of less than about 600 ohms per square and a temperature coefficient of resistance within ±150 ppm/°C.

Claim 40

A method for preparing an electrical resistor providing a resistivity of less than about 600 ohms per square and a temperature coefficient of resistance within ±150 ppm/°C. comprising the steps of: (a) placing termination comprising copper on an electrically insulating substrate; (b) coating a surface of the substrate with a mixture comprising from about 25 to about 35% by weight glass frit, from about 50 to about 75% by weight conductive particles, and at least 0.1% by weight of an oxide of manganese, the conductive particles consisting essentially of from about 97 to about 99% by weight tin oxide and from about 1% to about 3% by weight ruthenium oxide, the mixture being in contact with the terminations and being applied in a thickness of less than about 1.0 mil; (c) firing the coated substrate in a substantially non-oxidizing atmosphere to a temperature between about 350° and about 1050° C. at which the glass frit softens but the tin oxide does not melt; and (d) cooling the coated substrate to form a layer of glass bonded to the substrate and having the conductive particles dispersed throughout the glass, wherein the electrical resistor has a resistivity of less than about 600 ohms per square and a temperature coefficient of resistance within ±150 ppm/°C.