Temperature Sensor Structure

Abstract

A device for measuring temperature includes first and second temperature sensors enclosed in a first material having one or more material components, a contact surface for contacting a body whose temperature is to be measured, at least part of the contact surface being parallel to a lateral direction. The first and second temperature sensors are arranged at different depths from the contact surface and the net thermal conductivity across the device from the contact surface through the first and second temperature sensors is greater than the net lateral thermal conductivity of the device through the first and second temperature sensors.

1 . A device for measuring temperature comprising:
 first and second temperature sensors mounted on a circuit board and enclosed in a material comprising a first material component and a second material component, the first and second temperature sensors being embedded in the first material component and the second material component at least partially enclosing the first material component and having a lower thermal conductivity than the first material component; and   a contact surface for contacting a body whose temperature is to be measured;   wherein the first and second temperature sensors are arranged at different depths from the contact surface and the net thermal conductivity across the device from the contact surface through the first and second temperature sensors is greater than the net thermal conductivity of the device in lateral directions parallel to the contact surface;   wherein the circuit board extends substantially across the first material component between the first and second temperature sensors, the circuit board and first material component having substantially the same thermal conductivity of at least 0.5 W/mK.   
     
     
         2 . A device as claimed in  claim 1 , wherein the first material component has a greater thermal conductivity than the second material component by a factor of at least 4. 
     
     
         3 . A device as claimed in  claim 1 , wherein the second material component completely encloses the first material component. 
     
     
         4 . A device as claimed in  claim 3 , wherein the second material component is thicker over the lateral extremities of the first material component than over the contact surface and its opposing surface. 
     
     
         5 . A device as claimed in  claim 1 , wherein the first material component is substantially disc-shaped and the plane of the disc is substantially parallel to the contact surface. 
     
     
         6 . A device as claimed in  claim 5 , wherein the second material component forms a ring-shaped annulus about the disc-shaped first material, the plane of the ring being substantially coincident with the plane of the disc. 
     
     
         7 . A device as claimed in  claim 1 , wherein each depth is a distance from the contact surface to the respective temperature sensor along an axis substantially perpendicular to the contact surface. 
     
     
         8 . A device as claimed in  claim 1 , wherein each depth is a thermal depth defined by the net thermal conductance from the contact surface to the respective temperature sensor. 
     
     
         9 . A device as claimed in  claim 8 , wherein the first and second temperature sensors are at the same distance from the contact surface along an axis substantially perpendicular to the contact surface. 
     
     
         10 . A device as claimed in  claim 1 , wherein a surface of the first material component provides at least part of said contact surface. 
     
     
         11 . A device as claimed in  claim 1 , wherein the first material component comprises at least first and second material parts having different thermal conductivities, the first temperature sensor being embedded in the first material part and the second temperature sensor being embedded in the second material part. 
     
     
         12 . A device as claimed in  claim 11 , wherein at least part of the contact surface is provided by the first and second material parts. 
     
     
         13 . A device as claimed in  claim 1 , wherein the net thermal conductivity across the device is lowest in the lateral directions. 
     
     
         14 . A device as claimed in  claim 1 , wherein the first material component is a thermally conductive polymer. 
     
     
         15 . A device as claimed in  claim 1 , wherein, in use, a surface of the first material component remote from said contact surface is exposed. 
     
     
         16 . A device as claimed in  claim 15 , wherein said remote surface supports a thin layer having a higher thermal conductivity than the first material. 
     
     
         17 . A device as claimed in  claim 1 , wherein the first material component has a thermal conductivity of 3 W/mK. 
     
     
         18 . A device as claimed in  claim 1 , wherein the first material component has a greater thermal conductivity than the second material component by a factor of at least 10.