US4594569A — Humidity sensitive device

Claim 1

Independent Claim 117 words

A humidity sensitive device for sensing the humidity of an ambient atmosphere comprising: humidity sensitive resistor means for exhibiting an electrical resistance which is dependent upon chemisorption of water vapor at a temperature substantially above 200° C. where substantially no physisorption is possible to thereby responsively sense the humidity of an ambient atmosphere during a humidity sensing operation conducted at said temperature; said humidity sensitive resistor means consisting essentially of at least one main component selected from the group consisting of ZrO 2 , Nb 2 O 5 , and Ta 2 O 5 ; and electric heater means for maintaining said humidity sensitive resistor means at said temperature above 200° C. during said humidity sensing operation.

Claim 2

Dependent Claim 117 words

A humidity sensitive device for sensing the humidity of an ambient atmosphere comprising: humidity sensitive resistor means for exhibiting an electrical resistance which is dependent upon chemisorption of water vapor at a temperature substantially above 200° C. where substantially no physisorption is possible to thereby responsively sense the humidity of an ambient atmosphere during a humidity sensing operation conducted at said temperature; said humidity sensitive resistor means consisting essentially of at least one main component selected from the group consisting of ZrO 2 , Nb 2 O 5 , and Ta 2 O 5 ; and electric heater means for maintaining said humidity sensitive resistor means at said temperature above 200° C. during said humidity sensing operation.

Claim 3

Dependent Claim 43 words

A humidity sensitive device in accordance with claim 1 wherein said humidity sensitive resistor means comprises as main component said at least one substance selected from the group consisting of ZrO 2 , Nb 2 O 5 and Ta 2 O 5 .

Claim 4

Dependent Claim 44 words

A humidity sensitive device in accordance with claim 2, wherein said humidity sensitive resistor further consists essentially of a sub-component of at least one substance selected from the group consisting of BeO, MgO, CaO, BaO, SrO, ZnO, CdO and Al 2 O 3 .

Claim 5

Dependent Claim 167 words

A humidity sensitive device for sensing the humidity of an ambient atmosphere comprising: humidity sensitive resistor means for exhibiting an electrical resistance which is dependent upon chemisorption of water vapor at a temperature substantially above 200° C. to thereby responsively sense the humidity of an ambient atmosphere during a humidity sensing operation conducted at said temperature, said humidity sensitive resistor consisting essentially of at least one main component selected from the group consisting of ZrO 2 , Nb 2 O 5 and Ta 2 O 5 ; electric heater means fed with a controlled current for maintaining said humidity sensitive resistor means at said temperature substantially above 200° C. during said humidity sensing operation; a resistor which is connected in a series to said humidity sensitive resistor thereby forming a voltage divider; AC voltage source means for impressing a predetermined AC voltage across said voltage divider, means for measuring an AC output signal of said voltage divider and issuing an output responding to humidity of ambient atmosphere.

Claim 6

Dependent Claim 167 words

A humidity sensitive device for sensing the humidity of an ambient atmosphere comprising: humidity sensitive resistor means for exhibiting an electrical resistance which is dependent upon chemisorption of water vapor at a temperature substantially above 200° C. to thereby responsively sense the humidity of an ambient atmosphere during a humidity sensing operation conducted at said temperature, said humidity sensitive resistor consisting essentially of at least one main component selected from the group consisting of ZrO 2 , Nb 2 O 5 and Ta 2 O 5 ; electric heater means fed with a controlled current for maintaining said humidity sensitive resistor means at said temperature substantially above 200° C. during said humidity sensing operation; a resistor which is connected in a series to said humidity sensitive resistor thereby forming a voltage divider; AC voltage source means for impressing a predetermined AC voltage across said voltage divider, means for measuring an AC output signal of said voltage divider and issuing an output responding to humidity of ambient atmosphere.

Claim 7

Dependent Claim 43 words

A humidity sensitive device in accordance with claim 4 wherein said humidity sensitive resistor means contains as main component said at least one substance selected from the group consisting of ZrO 2 , Nb 2 O 5 and Ta 2 O 5 .

Claim 8

Dependent Claim 44 words

A humidity sensitive device in accordance with claim 5 wherein said humidity sensitive resistor means further consists essentially of as sub-component at least one substance selected from the group consisting of BeO, MgO, CaO, BaO, SrO, ZnO, CdO and Al 2 O 3 .

Claim 9

Dependent Claim 152 words

A humidity sensitive device for sensing the humidity of an ambient atmosphere, comprising: humidity sensitive resistor means having a metal oxide substrate and electrodes on one surface thereof, the resistivity of said humidity sensitive resistor means decreasing with an increase of the ambient humidity at a temperature above 200° C. to thereby responsively sense the humidity of an ambient atmosphere during a humidity sensing operation conducted at said temperature, wherein the effect due to water vapor physisorption becomes negligibly small at said temperature, said metal oxide substrate consisting essentially of, as solid ingredients, at least one main component selected from the group consisting of ZrO 2 , Nb 2 O 5 and Ta 2 O 5 ; and heater means, positioned in proximity to and in isolated relation from said humidity sensitive resistor means, for maintaining said humidity sensitive resistor means at said temperature above 200° C. during said humidity sensing operation.

Claim 10

Dependent Claim 152 words

A humidity sensitive device for sensing the humidity of an ambient atmosphere, comprising: humidity sensitive resistor means having a metal oxide substrate and electrodes on one surface thereof, the resistivity of said humidity sensitive resistor means decreasing with an increase of the ambient humidity at a temperature above 200° C. to thereby responsively sense the humidity of an ambient atmosphere during a humidity sensing operation conducted at said temperature, wherein the effect due to water vapor physisorption becomes negligibly small at said temperature, said metal oxide substrate consisting essentially of, as solid ingredients, at least one main component selected from the group consisting of ZrO 2 , Nb 2 O 5 and Ta 2 O 5 ; and heater means, positioned in proximity to and in isolated relation from said humidity sensitive resistor means, for maintaining said humidity sensitive resistor means at said temperature above 200° C. during said humidity sensing operation.

Claim 11

Dependent Claim 42 words

A humidity sensitive device in accordance with claim 7, wherein said metal oxide substrate further comprising, as solid ingredients, at least one sub-component selected from the group consisting of BeO, MgO, CaO, BaO, SrO, ZnO, CdO and Al 2 O 3 .

Claim 12

Dependent Claim 86 words

A humidity sensitive device according to claim 7, which further comprises; a fixed resistor coupled to said humidity sensitive resistor; a AC-DC converter coupled to said resistor for converting AC voltage to DC voltage; a comparator coupled to said converter for outputting a logic signal corresponding to the comparison between said DC voltage and a predetermined reference voltage; and a power source coupled to said heater for applying to said heater an electric power for keeping said humidity sensitive resistor at a temperature above 200° C.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1989-06-09	1989-12-09	1990-06-10	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1993-06-09	1993-12-09	1994-06-10	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1997-06-09	1997-12-09	1998-06-10	$7700.00	Window Closed / Lapsed

Humidity sensitive device

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