US4595485A — Limiting electric current type oxygen sensor

Claim 1

Independent Claim 121 words

A limiting electric current type oxygen sensor comprising an at least partially electrically insulating substrate, a first electrode of a gas-permeable film, a thin solid electrolyte film having a specific orientation of crystal and having a thickness between 0.1 μm and 30 μm, a second electrode of a gas-permeable film, means for determining a diffusion flow rate of a gas flowing therethrough, a portion of said substrate which corresponds to an oxygen concentration detecting portion being removed by etching; said first electrode, said thin solid electrolyte film and said second electrode being sequentially formed on said substate and means for applying positive voltage to one electrode, negative voltage to the other electrode and for detecting electrical current flow through said electrodes.

Claim 2

Dependent Claim 121 words

A limiting electric current type oxygen sensor comprising an at least partially electrically insulating substrate, a first electrode of a gas-permeable film, a thin solid electrolyte film having a specific orientation of crystal and having a thickness between 0.1 μm and 30 μm, a second electrode of a gas-permeable film, means for determining a diffusion flow rate of a gas flowing therethrough, a portion of said substrate which corresponds to an oxygen concentration detecting portion being removed by etching; said first electrode, said thin solid electrolyte film and said second electrode being sequentially formed on said substate and means for applying positive voltage to one electrode, negative voltage to the other electrode and for detecting electrical current flow through said electrodes.

Claim 3

Dependent Claim 40 words

A sensor according to claim 1, wherein said tin solid electrolyte film comprises zirconium oxide stabilized by at least one stabilizer selected from the group consisting of yttrium oxide, ytterbium oxide, gadolinium oxide, magnesium oxide, calcium oxide, and scandium oxide.

Claim 4

Dependent Claim 152 words

A sensor according to claim 2, further comprising a thin film heater provided on said substrate, and a processing circuit for processing current flow to determine gas diffusion flow rate wherein said substate comprises silicon and has at least part of said processing circuit formed thereon, said processing circuit including a converter for converting to a voltage output current flow through said electrodes, a circuit for measuring the resistance of said thin film heater and detecting heater temperature, a presetter for presetting a target temperature to control the heater temperature, a circuit for controlling power supply to said thin film heater, and a circuit for controlling heater temperature rise rate, and said porous coating layer comprises a material selected from the group consisting of aluminum oxide, silicon dioxide, spinnel, silicon carbide, and trisilicon tetranitride, and has a porosity of not more than 30% and a thickness of not less than 1 μm.

Claim 5

Dependent Claim 34 words

A sensor according to claim 1, wherein said thin solid electrolyte film comprises bismuth trioxide doped with at least one material selected from the group consisting of yttrium oxide, erbium oxide and tungsten trioxide.

Claim 6

Dependent Claim 153 words

A sensor according to claim 4, further comprising a thin film heater provided on said substrate, and a processing circuit for processing current flow to determine gas diffusion flow rate wherein said substrate comprises silicon and has at least part of said processing circuit formed thereon, said processing circuit including a converter for converting to a voltage an output current flow through said electrodes, a circuit for measuring the resistance of said thin film heater and detecting heater temperature, a presetter for presetting a target temperature to control the heater temperature, a circuit for controlling power supply to said thin film heater, and a circuit for controlling heater temperature rise rate, and said porous coating layer comprises a material selected from the group consisting of aluminum oxide, silicon dioxide, spinnel, silicon carbide, and trisilicon tetranitride, and has a porosity of not more than 30% and a thickness of not less than 1 μm.

Claim 7

Dependent Claim 130 words

A limiting electric current type oxygen sensor comprising an at least partially electrically insulating substrate, a first electrode of a gas-permeable film, a thin and dense solid electrolyte film which has a specific orientation of crystal and a thickness between 0.1 μm and 30 μm, said electrolyte film being devoid of glass-based material, a second electrode of a gas-permeable film, and means for determining a diffusion flow rate of a gas flowing therethrough; said means, said first electrode, said thin and dense solid electrolyte film and said second electrode being sequentially formed on said substrate, and means for applying positive voltage to one electrode, negative voltage to the other electrode and for detecting electrical current flow through said electrodes, thereby enabling said sensor to operate stably even at high temperatures.

Claim 8

Dependent Claim 130 words

A limiting electric current type oxygen sensor comprising an at least partially electrically insulating substrate, a first electrode of a gas-permeable film, a thin and dense solid electrolyte film which has a specific orientation of crystal and a thickness between 0.1 μm and 30 μm, said electrolyte film being devoid of glass-based material, a second electrode of a gas-permeable film, and means for determining a diffusion flow rate of a gas flowing therethrough; said means, said first electrode, said thin and dense solid electrolyte film and said second electrode being sequentially formed on said substrate, and means for applying positive voltage to one electrode, negative voltage to the other electrode and for detecting electrical current flow through said electrodes, thereby enabling said sensor to operate stably even at high temperatures.

Claim 9

Dependent Claim 46 words

A limiting electric current type oxygen sensor according to claim 6 wherein said means for determining the gas diffusion flow rate comprises an electrically insulating porous coating layer at least partially covering said substrate, said first electrode, said thin solid electrolyte film and said second electrode.

Claim 10

Dependent Claim 40 words

A sensor according to claim 7, wherein said first and second electrodes comprise an element selected from the group consisting of platinum, palladium, silver, and an alloy containing at least one of platinum, palladium and silver as a main constituent.

Claim 11

Dependent Claim 40 words

A sensor according to claim 7, wherein said thin solid electrolyte film comprises zirconium oxide stabilized by at least one stabilizer selected from the group consisting of yttrium oxide, ytterbium oxide, gadolinium oxide, magnesium oxide, calcium oxide, and scandium oxide.

Claim 12

Dependent Claim 34 words

A sensor according to claim 7, wherein said thin solid electrolyte film comprises bismuth trioxide doped with at least one material selected from the group consisting of yttrium oxide, erbium oxide and tungsten trioxide.

Claim 13

Dependent Claim 48 words

A sensor according to claim 7, wherein said porous coating layer comprises a material selected from the group consisting of aluminum oxide, silicon dioxide, spinnel, silicon carbide, and trisilicon tetranitride, and has a porosity of not more than 30% and a thickness of not less than 1 μm.

Claim 14

Dependent Claim 23 words

A sensor according to claim 7, further comprising a thin film heater between said substrate and said first electrode through an insulating film.

Claim 15

Dependent Claim 39 words

A sensor according to claim 7, further comprising a thin film heater on a surface of said substrate which opposes a surface thereof on which said first electrode, said thin solid electrolyte film and said second electrode are formed.

Claim 16

Dependent Claim 36 words

A sensor according to claim 7, further comprising a processing circuit for processing current flow to determine gas diffusion flow rate, said substrate comprising silicon and having at least part of said processing circuit formed thereon.

Claim 17

Dependent Claim 83 words

A sensor according to claim 14, further comprising a thin film heater on said substrate, wherein said processing circuit section includes a converter for converting to a voltage an output current generated from said sensor section, a circuit for measuring the resistance of said thin film heater and detecting heater temperature, a presetter for presetting a target temperature to control the heater temperature, a circuit for controlling power supply to said thin film heater, and a circuit for controlling heater temperature rise rate.

Claim 18

Dependent Claim 45 words

A sensor according to claim 7, wherein said substrate comprises a cylindrical body; said first electrode, said thin solid electrolyte film and said second electrode are formed on the outer surface of said cylindrical body; and a heater is formed on the inner surface thereof.

Claim 19

Dependent Claim 45 words

A sensor according to claim 6, further comprising a dense coating layer formed on the resultant structure of said substrate, said first electrode, said thin solid electrolyte film and said second electrode, said dense coating layer having an opening for limiting a gas flow path.

Claim 20

Dependent Claim 36 words

A sensor according to claim 17, wherein said substrate has a dense structure, the one of said first and second electrodes which is a cathode serving as said means for determining the gas diffusion flow rate.

Claim 21

Dependent Claim 25 words

A sensor according to claim 17, wherein said substrate has a gas-permeable structure and serves as said means for determining the gas diffusion flow rate.

Claim 22

Dependent Claim 40 words

A sensor according to claim 17, wherein said first and second electrodes comprise an element selected from the group consisting of platinum, palladium, silver, and an alloy containing at least one of platinum, palladium and silver as a main constituent.

Claim 23

Dependent Claim 40 words

A sensor according to claim 20, wherein said thin solid electrolyte film comprises zirconium oxide stabilized by at least one stabilizer selected from the group consisting of yttrium oxide, ytterbium oxide, gadolinium oxide, magnesium oxide, calcium oxide, and scandium oxide.

Claim 24

Dependent Claim 112 words

A sensor according to claim 21, further comprising a thin film heater provided on said substrate and a processing circuit for processing current flow to determine gas diffusion flow rate, wherein said substrate comprises silicon and has at least part of a processing circuit formed thereon, said processing circuit including a converter for converting to a voltage an output current flow through said electrodes, a circuit for measuring the resistance of said thin film heater and detecting a heater temperature, a presetter for presetting a target temperature to control the heater temperature, a circuit for controlling power supply to said thin film heater, and a circuit for controlling heater temperature rise rate.

Claim 25

Dependent Claim 34 words

A sensor according to claim 20, wherein said thin solid electrolyte film comprises bismuth trioxide doped with at least one material selected from the group consisting of yttrium oxide, erbium oxide and tungsten trioxide.

Claim 26

Dependent Claim 111 words

A sensor according to claim 23, further comprising a thin film heater provided on said substrate, wherein said substrate comprises silicon, at least part of a processing circuit section being together with a sensor section formed thereon, said processing circuit section being arranged to operate said sensor section, and including converter for converting to a voltage an output current generated from said sensor section, circuit for measuring a resistance of said thin film heater and detecting a heater temperature, a presetter for presetting target temperature to control the heater temperature, a circuit for controlling power supply to said thin film heater, and a circuit for controlling a heater temperature rise rate.

Claim 27

Dependent Claim 40 words

A sensor according to claim 17, wherein said thin solid electrolyte film comprises zirconium oxide stabilized by at least one stabilizer selected from the group consisting of yttrium oxide, ytterbium oxide, gadolinium oxide, magnesium oxide, calcium oxide, and scandium oxide.

Claim 28

Dependent Claim 34 words

A sensor according to claim 17, wherein said thin solid electrolyte film comprises bismuth trioxide doped with at least one material selected from the group consisting of yttrium oxide, erbium oxide and tungsten trioxide.

Claim 29

Dependent Claim 23 words

A sensor according to claim 17, further comprising a thin film heater between said substrate and said first electrode through an insulating film.

Claim 30

Dependent Claim 38 words

A sensor according to claim 17, further comprising a thin film heater on a surface of said substrate which opposes a surface thereof which said first electrode, said thin solid electrolyte film and said second electrode are formed.

Claim 31

Dependent Claim 103 words

A sensor according to claim 17, further comprising a processing circuit for processing current flow to determine gas diffusion flow rate wherein said substrate comprises silicon and has at least part of said processing circuit formed thereon, said processing circuit including a converter for converting to a voltage an output current flow through said electrodes, a circuit for measuring the resistance of said thin film heater and detecting a heater temperature, a presetter for presetting a target temperature to control the heater temperature, a circuit for controlling power supply to said thin film heater, and a circuit for controlling heater temperature rise rate.

Claim 32

Dependent Claim 84 words

A sensor according to claim 29, further comprising a thin film heater provided on said substrate, wherein said processing circuit section includes a converter for converting to a voltage an output current generated from said sensor section, a circuit for measuring the resistance of said thin film heater and detecting heater temperature, a presetter for presetting a target temperature to control the heater temperature, a circuit for controlling power supply to said thin film heater, and a circuit for controlling heater temperature rise rate.

Claim 33

Dependent Claim 49 words

A sensor according to claim 17, wherein said substrate comprises a cylindrical body; said first electrode, said thin solid electrolyte film, said second electrode and said dense coating layer are formed on the outer surface of said cylindrical body; and a heater is formed on the inner surface thereof.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1989-06-16	1989-12-16	1990-06-17	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1993-06-16	1993-12-16	1994-06-17	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1997-06-16	1997-12-16	1998-06-17	$7700.00	Window Closed / Lapsed

Limiting electric current type oxygen sensor

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag