公开(公告)号：US20240053261A1

公开(公告)日：2024-02-15

申请号：US18269322

申请日：2021-12-15

Applicant: National University Corporation YOKOHAMA National University ,  FIGARO ENGINEERING INC.

Inventor： Yoshiaki NISHIJIMA ,  Hiromasa TAKASHIMA ,  Tsuyoshi UEDA ,  Tomohiro KAWAGUCHI ,  Soichiro SAKAI

IPC: G01N21/3504 ,  G01N21/552

CPC classification number: G01N21/3504 ,  G01N21/554

Abstract: The infrared absorber 1 is provided with a finely structured metal layer 2 which causes local surface plasmon resonance by absorption infrared light; a dielectric layer 3 under the finely structured metal layer, and a metal layer 4 under the dielectric layer 3. The dielectric layer 3 is stacked between the layers 2 and 4 and consists of an organic polymer material having a molecular bond whose vibration is excited by infrared absorption. Further, the gas sensor is provided with the infrared absorber as the light source and/or the photodetector.

公开(公告)号：US20210270760A1

公开(公告)日：2021-09-02

申请号：US16973063

申请日：2019-04-24

Applicant: Figaro Engineering Inc.

Inventor： Masakazu SAI ,  Kuniyuki IZAWA ,  Tomohiro KAWAGUCHI

IPC: G01N27/12

Abstract: A gas detector uses a MEMS gas sensor having: a substrate provided with a cavity and an insulating film over the cavity; a metal oxide semiconductor and a heater both provided on the insulating film. A drive circuit operates the heater with a predetermined period for a predetermined pulse duration in order to heat the metal oxide semiconductor. The drive circuit halts operation of the heater or elongates the period when a humidity sensor detects that the atmosphere is humid.

公开(公告)号：US20210041386A1

公开(公告)日：2021-02-11

申请号：US16931485

申请日：2020-07-17

Applicant: Figaro Engineering Inc.

Inventor： Masafumi TOYOTA ,  Kunihiko MAEJIMA ,  Tomohiro KAWAGUCHI ,  Tatsuya ISHIMOTO

IPC: G01N27/12 ,  G01N33/00 ,  G01M3/40

Abstract: A gas detector comprises: plural gas sensors provided with a metal-oxide semiconductor whose resistance changes based upon contact with a gas; and a driving circuit for operating the gas sensors. The gas detector stores the ratio between initial resistance in air of the metal-oxide semiconductor and initial resistance of the metal-oxide semiconductor in an atmosphere including a predetermined concentration of fron gas, for the plural gas sensors. The gas detector learns resistance in air of the metal-oxide semiconductor in a gas sensor in use, and detects occurrence of fron gas when resistance of the metal-oxide semiconductor of the gas sensor in use becomes lower than a value corresponding to the learned resistance in air divided by the ratio. The gas detector counts the period that a first gas sensor is used. When the first gas sensor has been used for a predetermined period, both the first gas sensor and a second gas sensor are used for a learning period to continue detection of fron by the first gas sensor and to learn the resistance in air of the metal-oxide semiconductor of the second gas sensor. After completion of the learning period, fron leakage is detected by the second gas sensor.