Browse Prior Art Database

Fast and Local Thermometer and Flow Detector

IP.com Disclosure Number: IPCOM000123910D
Original Publication Date: 1999-Jul-01
Included in the Prior Art Database: 2005-Apr-05
Document File: 1 page(s) / 36K

Publishing Venue

IBM

Related People

Binnig, GK: AUTHOR [+4]

Abstract

A temperature sensitive resistor 1 (e.g. silicon) of roughly micrometer size is mounted at the end of a micro mechanical structure like a cantilever 2. The cantilever 2 (with possibly two arms, see Fig. 1) serves as electrical contact, as mechanical holder of the resistor, and as thermal resistor at the same time. The design is made in a way, that the mass, i.e., the heat capacitance, of the resistor 1 is as small as possible. This way a microseconds response time or better is possible and the sensing is very local.

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Fast and Local Thermometer and Flow Detector

   A temperature sensitive resistor 1 (e.g. silicon) of
roughly micrometer size is mounted at the end of a micro mechanical
structure like a cantilever 2.  The cantilever 2 (with possibly two
arms, see Fig. 1) serves as electrical contact, as mechanical holder
of the resistor, and as thermal resistor at the same time.  The
design is made in a way, that the mass, i.e., the heat capacitance,
of the resistor 1 is as small as possible.  This way a microseconds
response time or better is possible and the sensing is very local.

   The design of the thermal resistor depends on the
application.  For extremely small amounts of sample material or weak
thermal coupling between resistor and the medium to be measured its
thermal resistance has to be larger and speed has to be sacrificed.

   When the resistor is used as a thermometer, its power
consumption should be low to avoid internal heating.  For high power
consumption the resistor can be used as a tool to measure a material
flow.  The flow of gas or liquid will cool the resistor more or less
depending on the flow speed.  This information is very local.

   The resistor can have the shape of a tip and can be used
as an AFM sensor.  This may result in a kind of chemical sensing as
the heat conductivity depends on the material that is in contact with
the tip.