Thermopile infrared individual sensor for measuring temperature or detecting gas

Abstract

A thermopile infrared individual sensor includes a housing filled with a gaseous medium. It has optics and one or more sensor chips with individual sensor cells with infrared sensor structures with reticulated membranes, infrared-sensitive regions of which are each spanned by at least one beam over a cavity in a carrier body. The thermopile infrared sensor uses monolithic Si-micromechanics technology for contactless temperature measurements. In the case of a sufficiently large receiver surface, this outputs a high signal with a high response speed. A plurality of individual adjacent sensor cells are combined with respectively one infrared-sensitive region with thermopile structures on the membrane on a common carrier body of an individual chip to a single thermopile sensor structure with a signal output in the housing, consisting of a cap sealed with a base plate with a common gaseous medium.

1 . A thermopile infrared sensor, comprising:
 a housing filled with a gas medium, the housing having a base plate and a cap;   an optical unit arranged at an aperture opening in the housing; and   a sensor chip having a plurality of sensor cells, each of the plurality of sensor cells having a thermopile infrared-sensitive region, the plurality of sensor cells being arranged on a common carrier body to form a thermopile sensor structure,   wherein sensor cells of the plurality of sensor cells are interconnected with one another to form an effective thermopile individual sensor,   wherein each sensor cell of the plurality of sensor cells generates an output signal, and   wherein the output signals of the plurality of sensor cells are combined to form one output signal of the thermopile infrared sensor.   
     
     
         2 . The thermopile infrared sensor as in  claim 1 , wherein the sensor cells of the plurality of sensor cells are connected in series, in parallel or in a combination of series and parallel circuit to form the one output signal. 
     
     
         3 . The thermopile infrared sensor as in  claim 1 , wherein the one output signal is formed by use of preamplifiers or impedance converters or multiplexers or microcontrollers as a summation element. 
     
     
         4 . The thermopile infrared sensor as in  claim 3 , wherein each preamplifier is an impedance converter or a low pass filter. 
     
     
         5 . The thermopile infrared sensor as in  claim 1 ,
 wherein the common carrier body comprises a plurality of cavities, and   wherein each of the plurality of sensor cells comprises
 a membrane extending over one cavity of the plurality of cavities, a central sensitive portion of the membrane being the thermopile infrared-sensitive region; 
 a beam structure connecting the central sensitive portion of the membrane with the carrier body, 
 a hot contact thermocouple arranged on the central sensitive portion of the membrane, and 
 a cold contact thermocouple arranged on the carrier body. 
   
     
     
         6 . The thermopile infrared sensor as in  claim 5 , wherein adjacent ones of the plurality of cavities are separated by the carrier body. 
     
     
         7 . The thermopile infrared sensor as in  claim 1 ,
 wherein each of the plurality of sensor cells further comprises two terminal pads, and   wherein adjacent ones of the plurality of sensor cells are electrically connected by wire bridges.   
     
     
         8 . The thermopile infrared sensor as in  claim 5 , wherein the beam structure comprises
 a first L-shaped beam and   a second L-shaped beam,   the first L-shaped beam and the second L-shaped beam being arranged in a mirrored configuration to form a rectangular beam structure.   
     
     
         9 . The thermopile infrared sensor as in  claim 8 ,
 wherein the cavities of the plurality of cavities have generally vertical walls, and   wherein the first L-shaped beam is arranged above the cavity and proximal to two adjacent ones of the generally vertical walls of the respective cavity, and   wherein the second L-shaped beam is arranged above the cavity and proximal to two further adjacent ones of the generally vertical walls of the respective cavity.   
     
     
         10 . The thermopile infrared sensor as in  claim 8 ,
 wherein the cavities of the plurality of cavities have inclined walls, and   wherein the first L-shaped beam is arranged above two adjacent ones of the inclined walls, and   wherein the second L-shaped beam is arranged above to two further adjacent ones of the inclined walls.   
     
     
         11 . The thermopile infrared sensor as in  claim 5 , wherein the beam structure of each of
 the plurality of sensor cells comprises   a first beam;   a first outer slot separating the first beam from the carrier body;   a first inner slot separating the first beam from the membrane;   a second beam;   a second outer slot separating the second beam from the carrier body; and   a second inner slot separating the second beam from the membrane.   
     
     
         12 . The thermopile infrared sensor as in  claim 5 , wherein an absorber layer having a thickness of less than 1 μm is arranged on the membrane. 
     
     
         13 . The thermopile infrared sensor as in  claim 1 , wherein the gas medium comprises one or more of xenon, krypton, and argon. 
     
     
         14 . The thermopile infrared sensor as in  claim 1 ,
 wherein the housing is sealed against its surroundings and   wherein an internal pressure of the gas medium is below standard atmospheric pressure.   
     
     
         15 . The thermopile infrared sensor as in  claim 1 ,
 wherein the plurality of sensor cells and a plurality of preamplifiers are formed from a common substrate.   
     
     
         16 . The thermopile infrared sensor as in  claim 1 ,
 wherein the sensor chip comprises 2, 4, 9, or 16 sensor cells.   
     
     
         17 . The thermopile infrared sensor as in  claim 1 , wherein the thermopile infrared sensor is a gas detector. 
     
     
         18 . The thermopile infrared sensor as in  claim 1 , wherein two or four sensor chips are arranged adjacent to one another in the housing to form one or more channel for NDIR gas detection. 
     
     
         19 . The thermopile infrared sensor as in  claim 18 , wherein between adjacent channels is disposed an optical partition wall to prevent crosstalk between the channels.