# US 12,007,348 B2 · Method for driving gas sensor, and gas detection device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,007,348 B2 - Document ID: US12007348B2 - Status: Granted - Kind: B2 - Application number: 17/496,468 - Filed: 2021-10-07 - Published: 2022-01-27 - Granted: 2024-06-11 - Earliest claimed: 2019-04-16 - Assignees: Nuvoton Technology Corporation Japan - Applicants: Nuvoton Technology Corporation Japan - Inventors: Kazunari Homma; Koji Katayama; Shunsaku Muraoka; Ken Kawai - Web page: https://patentgrep.com/patent/US12007348B2 ## CPC - G01N 27/125: {Composition of the body, e.g. the composition of its sensitive layer} - G01N 27/12: of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid {, for detecting components in the fluid} - G01N 33/005: {H2} - G01R 19/0092: {Measuring current only} - G01R 27/02: Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant (by measuring phase angle only G01R25/00) - G01R 27/14: Measuring resistance by measuring current or voltage obtained from a reference source (G01R27/16, G01R27/20, G01R27/22 take precedence) - H10P 74/277: {Circuits for electrically characterising or monitoring manufacturing processes, e.g. circuits in tested chips or circuits in testing wafers} - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract A gas sensor driving method for a gas sensor that (i) includes: a first electrode including a first principal surface; a second electrode including a second principal surface; a metal-oxide layer interposed between the first principal surface and the second principal surface that face each other; and an insulating film covering the first electrode, the metal-oxide layer, and the second electrode, and exposing at least a part of a third principal surface of the second electrode, the third principal surface being disposed on an opposite side of the second principal surface, and (ii) detects hydrogen in accordance with a change in a resistance value of the metal-oxide layer. The gas sensor driving method includes repeatedly applying a positive voltage and a negative voltage across the first electrode and the second electrode. ## Claims ### Claim 1 A gas sensor driving method for a gas sensor that (i) includes: a first electrode including a first principal surface; a second electrode including a second principal surface; a metal-oxide layer interposed between the first principal surface and the second principal surface that face each other; and an insulating film covering the first electrode, the metal-oxide layer, and the second electrode, and exposing at least a part of a third principal surface of the second electrode, the third principal surface being disposed on an opposite side of the second principal surface, and (ii) detects hydrogen in accordance with a change in a resistance value of the metal-oxide layer occurring when the part of the third principal surface contacts gas including gas molecules containing hydrogen atoms in a state in which a voltage is applied across the first electrode and the second electrode, the gas sensor driving method comprising: repeats firstly applying a positive voltage and subsequently applying a negative voltage across the first electrode and the second electrode. ### Claim 2 (depends on 1) The gas sensor driving method according to claim 1, wherein the repeated applying of the positive voltage and the negative voltage is performed at all times regardless of whether or not the gas molecules are present in the gas that contacts the part of the third principal surface. ### Claim 3 (depends on 1) The gas sensor driving method according to claim 1, wherein the resistance value of the metal-oxide layer decreases when the part, which is exposed, of the third principal surface contacts the gas including the gas molecules containing the hydrogen atoms in the state in which the voltage is applied across the first electrode and the second electrode. ### Claim 4 (depends on 1) The gas sensor driving method according to claim 1, wherein when the positive voltage is applied, one or more positive voltage pulses are applied. ### Claim 5 (depends on 1) The gas sensor driving method according to claim 1, wherein when the negative voltage is applied, one or more negative voltage pulses are applied. ### Claim 6 (depends on 4) The gas sensor driving method according to claim 4, wherein when the one or more positive voltage pulses are applied, a value of a current flowing across the first electrode and the second electrode is read out. ### Claim 7 (depends on 1) The gas sensor driving method according to claim 1, wherein an absolute value of an applied voltage in the application of the positive voltage is larger than an absolute value of an applied voltage in the application of the negative voltage. ### Claim 8 (depends on 1) The gas sensor driving method according to claim 1, wherein a state in which no voltage is applied across the first electrode and the second electrode is present (i) between the application of the positive voltage and the application of the negative voltage, the application of the negative voltage following the application of the positive voltage or (ii) between the application of the negative voltage and the application of the positive voltage, the application of the positive voltage following the application of the negative voltage. ### Claim 9 (depends on 1) The gas sensor driving method according to claim 1, wherein when the positive voltage is applied, a first positive voltage and a second positive voltage are applied, and an absolute value of an applied voltage in the application of the first positive voltage is larger than an absolute value of an applied voltage in the application of the second positive voltage. ### Claim 10 (depends on 9) The gas sensor driving method according to claim 9, wherein the application of the second positive voltage is performed after the application of the first positive voltage and before the application of the negative voltage, the application of the negative voltage following the application of the first positive voltage. ### Claim 11 (depends on 9) The gas sensor driving method according to claim 9, wherein the application of the second positive voltage is performed after the application of the negative voltage and before the application of the first positive voltage, the application of the first positive voltage following the application of the negative voltage. ### Claim 12 (depends on 9) The gas sensor driving method according to claim 9, wherein the absolute value of the applied voltage in the application of the second positive voltage is smaller than an absolute value of an applied voltage in the application of the negative voltage. ### Claim 13 A gas detection device, comprising: a gas sensor that includes: a first electrode including a first principal surface, a second electrode including a second principal surface, a metal-oxide layer interposed between the first principal surface and the second principal surface that face each other, an insulating film covering the first electrode, the metal-oxide layer, and the second electrode, and exposing at least a part of a third principal surface of the second electrode, the third principal surface being disposed on an opposite side of the second principal surface; and a power circuit that repeats firstly applying a positive voltage and subsequently applying a negative voltage across the first electrode and the second electrode in the gas sensor. ### Claim 14 (depends on 13) The gas detection device according to claim 13, wherein the power circuit includes a voltage pulse generator circuit. ### Claim 15 (depends on 13) The gas detection device according to claim 13, further comprising: a measurement circuit that measures a resistance value of the gas sensor.