# US 11,079,321 B2 · NDIR detector device for detecting gases having an infrared absorption spectrum > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,079,321 B2 - Document ID: US11079321B2 - Status: Granted - Kind: B2 - Application number: 16/584,808 - Filed: 2019-09-26 - Published: 2020-04-02 - Granted: 2021-08-03 - Earliest claimed: 2018-09-28 - Assignees: STMicroelectronics S.r.l. - Applicants: Stmicroelectronics S.R.L. - Inventors: Maria Eloisa Castagna; Salvatore Cascino; Viviana Cerantonio; Antonello Santangelo - Web page: https://patentgrep.com/patent/US11079321B2 ## CPC - G01N 21/3504: for analysing gases, e.g. multi-gas analysis - 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) ## Abstract The device is formed in a casing including a support, a spacer body, and a mirror element fixed together. A light-emitting element and a light-receiving element are arranged on a bearing surface of the support and face a reflecting surface of the mirror element. The light-emitting element is configured to generate infrared radiation, and the light-receiving element is configured to receive light radiation reflected by the reflecting surface. The spacer body has an emission opening housing the light-emitting element and a reception opening housing the light-receiving element; the reception opening comprises a radiation-limitation portion configured to enable entry of reflected light radiation having an angle, with respect to a normal to the bearing surface, of less than a preset value. ## Claims ### Claim 1 An NDIR detector device for detecting molecules in a gas, comprising: a casing including a support, a spacer body, and a mirror element fixed together, the support having a bearing surface and the mirror element having a reflecting surface; a light-emitting element arranged on the bearing surface and facing the reflecting surface, the light-emitting element being configured to direct infrared radiation toward the reflecting surface; and a light-receiving element arranged on the bearing surface and facing the reflecting surface, the light-receiving element being configured to receive light radiation reflected by the reflecting surface, wherein the spacer body has an emission opening housing the light-emitting element and a reception opening housing the light-receiving element, and wherein the reception opening comprises a radiation-limitation portion configured to prevent entry of reflected light radiation having an angle, with respect to a normal to the bearing surface, of greater than a preset value. ### Claim 2 (depends on 1) The device according to claim 1, wherein the reflecting surface has a curved shape. ### Claim 3 (depends on 1) The device according to claim 1, wherein the reflecting surface has a shape of a surface portion of an ellipsoid having a first focus and a second focus and wherein the light-emitting element and the light-receiving element are arranged at the first focus and at the second focus, respectively. ### Claim 4 (depends on 1) The device according to claim 1, wherein the light-receiving element comprises a photodetector and a reception filter. ### Claim 5 (depends on 4) The device according to claim 4, wherein the photodetector is a photodetector element chosen in the group consisting of a thermopile, a bolometer, and a pyrometer, and the reception filter is a filter element chosen in the group consisting an interferential filter, a plasmonic filter, a sapphire filter, and a KBr filter. ### Claim 6 (depends on 5) The device according to claim 5, wherein the photodetector comprises a plurality of photodetector elements arranged side-by-side and the reception filter comprises a plurality of filter elements, the filter elements having different absorption/transmission bands and being respectively arranged above photodetector elements. ### Claim 7 (depends on 1) The device according to claim 1, wherein at least one of the light-emitting element and the light-receiving element is formed by an optical component comprising a structural region, an active region, and a cap region, of semiconductor material, overlying each other and bonded together, the structural region, the active region, and the cap region defining an inner chamber housing an active structure. ### Claim 8 (depends on 7) The device according to claim 7, wherein the cap region has a thin portion transparent to light. ### Claim 9 (depends on 8) The device according to claim 8, wherein the optical component comprises an integrated filter formed above the thin portion of the cap region. ### Claim 10 (depends on 8) The device according to claim 8, wherein the optical component comprises an integrated lens formed above the thin portion of the cap region. ### Claim 11 (depends on 1) The device according to claim 1, wherein the emission opening is defined by blackened walls. ### Claim 12 (depends on 1) The device according to claim 1, wherein: the mirror element and the spacer body are formed by molded plastic pieces bonded together; the mirror element includes a dome portion defining the reflecting surface and delimiting, with the spacer body, a reflection chamber; and the spacer body has a parallelepipedal shape forming the emission opening, the reception opening, and a gas-inlet channel fluidically connecting the external environment to the reflection chamber. ### Claim 13 (depends on 12) The device according to claim 12, wherein the gas-inlet channel comprises a groove extending between two opposite walls of the spacer body, and at least one slit extending between the groove and the reflection chamber. ### Claim 14 (depends on 12) The device according to claim 12, wherein the emission opening comprises an emission through hole and a source cavity aligned to the emission through hole, facing the support and housing a light source of the light-emitting element, and the reception opening comprises a reception through hole and a photodetector cavity aligned to the reception through hole and facing the support. ### Claim 15 (depends on 14) The device according to claim 14, wherein the spacer body further comprises a first filter cavity aligned to the emission through hole and facing the dome portion. ### Claim 16 (depends on 15) The device according to claim 15, wherein the spacer body further comprises a second filter cavity aligned to the reception hole and facing the dome portion. ### Claim 17 (depends on 12) The device according to claim 12, wherein the support comprises a printed-circuit board, the device further comprising: a control unit carried by the printed-circuit board; and electrical connections housed by the printed-circuit board and electrically coupling the control unit to the light-emitting element and to the light-receiving element. ### Claim 18 A detector device for detecting molecules in a gas, comprising: a casing including a support, a spacer body, and a mirror element fixed together, the support having a bearing surface and the mirror element having a reflecting surface; a light-emitting element arranged on the bearing surface and facing the reflecting surface, the light-emitting element being configured to direct infrared radiation toward the reflecting surface; and a light-receiving element arranged on the bearing surface and facing the reflecting surface, the light-receiving element being configured to receive light radiation reflected by the reflecting surface, wherein: the spacer body has an emission opening housing the light-emitting element and a reception opening housing the light-receiving element; the spacer body includes reception wall portions extending upwardly from the light-receiving element toward the mirror element and defining the reception opening. ### Claim 19 (depends on 18) The device according to claim 18, wherein the emission opening comprises an emission through hole and a source cavity aligned to the emission through hole, facing the support and housing a light source of the light-emitting element, and the reception opening comprises a reception through hole and a photodetector cavity aligned to the reception through hole and facing the support. ### Claim 20 (depends on 19) The device according to claim 19, wherein the spacer body further comprises a first filter cavity aligned to the emission through hole and facing the dome portion, and a second filter cavity aligned to the reception hole and facing the dome portion. ### Claim 21 A detector device for detecting molecules in a gas, comprising: a support having a bearing surface; a mirror element having a dome portion defining a reflecting surface; a light-emitting element arranged on the bearing surface and facing the reflecting surface, the light-emitting element being configured to direct infrared radiation toward the reflecting surface; a light-receiving element arranged on the bearing surface and facing the reflecting surface, the light-receiving element being configured to receive light radiation reflected by the reflecting surface; and a spacer body positioned between the support and the mirror element and delimiting, with the dome portion, a reflection chamber, wherein the spacer body includes: an emission opening housing the light-emitting element; a reception opening housing the light-receiving element; reception wall portions extending upwardly from the light-receiving element toward the mirror element and defining the reception opening; and a gas-inlet channel fluidically connecting an external environment to the reflection chamber. ### Claim 22 (depends on 21) The device according to claim 21, wherein the gas-inlet channel comprises a groove extending between two opposite walls of the spacer body, and at least one slit extending between the groove and the reflection chamber. ### Claim 23 (depends on 21) The device according to claim 21, wherein the emission opening comprises an emission through hole and a source cavity aligned to the emission through hole, facing the support and housing a light source of the light-emitting element, and the reception opening comprises a reception through hole and a photodetector cavity aligned to the reception through hole and facing the support.