# US 8,772,722 B2 · Temperature sensor and living body detector using temperature sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,772,722 B2 - Document ID: US8772722B2 - Status: Granted - Kind: B2 - Application number: 12/974,711 - Filed: 2010-12-21 - Published: 2011-06-30 - Granted: 2014-07-08 - Earliest claimed: 2009-12-28 - Assignees: Ricoh Company, Ltd. - Applicants: Hidetaka Noguchi; Hirofumi Watanabe - Inventors: Hidetaka Noguchi; Hirofumi Watanabe - Web page: https://patentgrep.com/patent/US8772722B2 ## CPC - G01J 5/07: Arrangements for adjusting the solid angle of collected radiation, e.g. adjusting or orienting field of view, tracking position or encoding angular position (optical collimating elements G01J5/0806) - G01J 5/0022: {for sensing the radiation of moving bodies} - G01J 5/0025: {Living bodies (ear thermometers G01J5/0011; detecting, measuring or recording for diagnostic purposes A61B5/00)} - G01J 5/0295: {Nulling devices or absolute detection} - G01J 5/12: using thermoelectric elements, e.g. thermocouples - G01J 5/22: Electrical features thereof - G01J: MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY (light sources F21, H01J, H01K, H05B; investigating properties of materials by optical means G01N) ## Abstract Disclosed is a temperature sensor using a work-function-difference-based radiant-ray detecting element that outputs, as a detecting signal of radiant rays, a work function difference between gate electrodes of first and second field-effect transistors sensing the radiant rays. The temperature sensor includes at least a pair of a first work-function-difference-based radiant-ray detecting element having a positive output temperature coefficient; and a second work-function-difference-based radiant-ray detecting element having a negative output temperature coefficient of which an absolute value is equal to an absolute value of the output temperature coefficient of the first work-function-difference-based radiant-ray detecting element. ## Claims ### Claim 1 A temperature sensor using a work-function-difference-based radiant-ray detecting element that outputs, as a detecting signal of radiant rays, a work function difference between gate electrodes of first and second field-effect transistors sensing the radiant rays, the temperature sensor comprising at least a pair of: a first work-function-difference-based radiant-ray detecting element having a positive output temperature coefficient; and a second work-function-difference-based radiant-ray detecting element having a negative output temperature coefficient of which an absolute value is equal to an absolute value of the output temperature coefficient of the first work-function-difference-based radiant-ray detecting element. ### Claim 2 (depends on 1) The temperature sensor according to claim 1, wherein each of the first and second work-function-difference-based radiant-ray detecting elements has one or more MOSFETs functioning as a current source and one or more MOSFETs for outputting the work function difference connected between a power source and a ground, and the first and second work-function-difference-based radiant-ray detecting elements are so arranged that the MOSFETs functioning as the current source and the MOSFETs for outputting the work function difference are connected in a reverse order between the power source and the ground. ### Claim 3 (depends on 2) The temperature sensor according to claim 2, wherein a heat insulating structure and a radiation-ray absorbing film are provided, and the first and second work-function-difference-based radiant-ray detecting elements and the radiation-rays absorbing film are provided on the heat insulating structure. ### Claim 4 (depends on 2) The temperature sensor according to claim 2, wherein an output of the work function difference from the first work-function-difference-based radiant-ray detecting element is input to a gate of the second work-function-difference-based radiant-ray detecting element, and a voltage smaller than a power source voltage of the second work-function-difference-based radiant-ray detecting element is supplied to the first work-function-difference-based radiant-ray detecting element. ### Claim 5 (depends on 4) A living body detector that detects radiation rays from a living body to detect the same, the living body detector comprising: the temperature sensor according to claim 4; and a peripheral circuit including an amplification circuit that amplifies an output signal from the temperature sensor and a comparison circuit that outputs a detection signal if an output from the amplification circuit exceeds a prescribed voltage range. ### Claim 6 (depends on 5) The living body detector according to claim 5, further comprising: an optical system that condenses the radiation rays from the living body. ### Claim 7 (depends on 2) The temperature sensor according to claim 2, wherein an output of the work function difference from the second work-function-difference-based radiant-ray detecting element is input to a gate of the first work-function-difference-based radiant-ray detecting element, and a voltage smaller than a power source voltage of the first work-function-difference-based radiant-ray detecting element is supplied to the second work-function-difference-based detecting element. ### Claim 8 (depends on 2) A living body detector that detects radiation rays from a living body to detect the same, the living body detector comprising: the temperature sensor according to claim 2; and a peripheral circuit including a summing circuit that sums up an output from the first work-function-difference-based radiant-ray detecting element constituting the temperature sensor and an output from the second work-function-difference-based radiant-ray detecting element, an amplification circuit that amplifies an output signal from the summing circuit, and a comparison circuit that outputs a detection signal if an output from the amplification circuit exceeds a prescribed voltage range. ### Claim 9 (depends on 8) The living body detector according to claim 8, wherein the temperature sensor and the peripheral circuit are integrated into one chip. ### Claim 10 (depends on 1) The temperature sensor according to claim 1, wherein each of the first and second work-function-difference-based radiant-ray detecting elements is composed of plural MOSFETs, and the MOSFETs constituting the first work-function-difference-based radiant-ray detecting element and the MOSFETs constituting the second work-function-difference-based radiant-ray detecting element are different in their channel conductivity types. ### Claim 11 (depends on 10) The temperature sensor according to claim 10, wherein the first work-function-difference-based radiant-ray detecting element is composed of plural PMOS transistors, a gate of one of the plural PMOS transistors is different in the conductivity type from gates of the other of the plural PMOS transistors, the second work-function-difference-based radiant-ray detecting element is composed of plural NMOS transistors, and a gate of one of the plural NMOS transistors is different in the conductivity type from gates of the other of the plural NMOS transistors. ### Claim 12 (depends on 10) The temperature sensor according to claim 10, wherein the first work-function-difference-based radiant-ray detecting element is composed of plural NMOS transistors, a gate of one of the plural NMOS transistors is the same in the conductivity type as but different in an impurity concentration from gates of the other of the plural NMOS transistors, the second work-function-difference-based radiant-ray detecting element is composed of plural PMOS transistors, and a gate of one of the plural PMOS transistors is the same in the conductivity type as but different in the impurity concentration from gates of the other of the plural PMOS transistors.