GB2120453A - Temperature sensor - Google Patents
Temperature sensor Download PDFInfo
- Publication number
- GB2120453A GB2120453A GB08212717A GB8212717A GB2120453A GB 2120453 A GB2120453 A GB 2120453A GB 08212717 A GB08212717 A GB 08212717A GB 8212717 A GB8212717 A GB 8212717A GB 2120453 A GB2120453 A GB 2120453A
- Authority
- GB
- United Kingdom
- Prior art keywords
- temperature sensor
- resistance element
- substrate
- sensor according
- aperture
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000000758 substrate Substances 0.000 claims abstract description 59
- 238000010304 firing Methods 0.000 claims abstract description 11
- 238000007650 screen-printing Methods 0.000 claims abstract description 11
- 229910010293 ceramic material Inorganic materials 0.000 claims abstract description 9
- 239000000919 ceramic Substances 0.000 claims abstract description 6
- 239000000203 mixture Substances 0.000 claims description 18
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 claims description 10
- 239000011248 coating agent Substances 0.000 claims description 9
- 238000000576 coating method Methods 0.000 claims description 9
- 239000012530 fluid Substances 0.000 claims description 9
- 238000005259 measurement Methods 0.000 claims description 9
- 239000004020 conductor Substances 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 6
- 229910052697 platinum Inorganic materials 0.000 claims description 5
- 238000002485 combustion reaction Methods 0.000 claims description 4
- 239000011195 cermet Substances 0.000 claims description 3
- 239000012777 electrically insulating material Substances 0.000 claims description 2
- 229910052751 metal Inorganic materials 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims description 2
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 239000011253 protective coating Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/10—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring thermal variables
- G01P5/12—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring thermal variables using variation of resistance of a heated conductor
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/18—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer
- G01K7/183—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a linear resistance, e.g. platinum resistance thermometer characterised by the use of the resistive element
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Aviation & Aerospace Engineering (AREA)
- Measuring Volume Flow (AREA)
Abstract
A temperature sensor particularly suitable for use as or in an anemometer comprises a ceramic substrate (1); a temperature sensitive elongate film electrical resistance element (2) adhered to a major surface of the substrate adjacent an edge thereof; film electrically conductive terminations (3) adhered to the substrate and extending from the resistance element (2) to an edge (4) of the substrate; and an aperture (5) provided through the substrate adjacent the resistance element (3) such that a narrow strip (6) of the substrate is formed with the resistance element (2) adhered thereto. A second film resistance element (7) and terminations (8) may also be provided, together with a further aperture (9) through the substrate and such that this second element is adhered to a narrow strip (10) of the substrate. A plurality of such sensors is conveniently formed on a single sheet of ceramic material which is subsequently cut or fractured to separate the individual sensors. The resistance elements are preferably of thick film form, produced by screen printing and firing. <IMAGE>
Description
SPECIFICATION
Temperature sensor
This invention relates to a temperature sensor and to a process for its manufacture. It is particularly, although not exclusively applicable to a temperature sensor of small size which is suitable for use in the measurement of fluid flow, e.g. as an anemometer, such as for the measurement of mass air flow in the intake manifold of an internal combustion engine.
The present invention provides a temperature sensor comprising: a ceramic substrate; an elongate film electrical resistance element adhered to a major surface of said substrate adjacent an edge thereof, said element having an electrical resistance value which changes significantly with temperature over a predetermined temperature range; film electrically conductive terminations adhered to said substrate and extending from said resistance element; an aperture provided through said substrate adjacent said resistance element, said aperture being dimensioned and arranged such that a narrow strip of said substrate is formed with said resistance element adhered thereto.
A second elongate film electrical resistance element and terminations therefor may be provided adhered to said substrate either on said major surface of said substrate or on an opposite major surface of said substrate.
Suitably said second resistance element is located adjacent an edge of said aperture, a second aperture being provided through said substrate adjacent said second resistance element, said second aperture being dimensioned and arranged with respect to said second resistance element such that a further narrow strip of said substrate is formed with said second resistance element adhered thereto.
Suitably said aperture, and said further aperture where provided, has or have been formed by cutting said substrate by means of a laser beam.
Conveniently said aperture, and said further aperture where provided, has or have been formed after providing said resistance element or elements.
Preferably said resistance element or elements comprises or comprise a thick film resistor material and has or have been conveniently
provided by screen printing and firing a suitable
thick film resistor composition, such as a cermet composition or a metal resinate composition.
Preferably the resistance element(s) comprise(s) or include(s) platinum.
The said terminations for said resistance element or elements may suitably extend to an
edge of said substrate.
The said terminations suitably comprise a thick film conductive material and have conveniently
been provided by screen printing and firing a
suitably thick film conductor composition. A coating of electrically insulating material may be
provided overlying said resistance element or elements and, if required, at least part of said terminations. In one embodiment, said coating suitably comprises a glaze; conveniently said glaze has been formed by screen printing and firing a suitable composition onto said sensor. Preferably said temperature sensor has been provided as one of a plurality of such sensors, said plurality of sensors having been formed by a single sequence of operations on a wafer of ceramic material, said ceramic material having been suitably cut or fractured to separate each said temperature sensor.Suitably said wafer of ceramic material has been cut by means of a laser beam.
In this way, temperature sensors having closely matched parameters can be readily obtained. This means of manufacture also facilitates the provision of the one or more apertures in the substrate of each sensor since the apertures can be formed prior to separating the wafer of ceramic material into the individual sensors.
The present invention accordingly also provides a process for manufacturing said temperature sensor. The provision of the one or more apertures in the substrate of the temperature sensor is particularly advantageous in that it effectively reduces the thermal mass of the sensor. The temperature sensor of the invention is particularly applicable for use in fluid flow measurement. An example of an application is an anemometer for the measurement of mass air flow in the intake manifold of an internal combustion engine, the temperature sensor being located in the airstream to be monitored.
In one embodiment of this application a temperature sensor according to the present invention is provided employing a said resistance element and a said further resistance element.
One of said resistance elements is arranged to be heated by passage therethrough of an electric current, measurement of the electric current required to maintain the resistance element at a predetermined temperature above the ambient level being used to give a measure of the mass air flow. The other resistance element is used as a reference to indicate the ambient temperature level.
In order to effect greater thermal isolation between the two resistance elements required in an anemometer, instead of using a single temperature sensor provided with two resistance elements thereon, two separate sensors may be provided, each employing a single resistance element. The sensors are arranged to be spaced and offset in the airstream to be monitored, the resistance element on one of the sensors being arranged to be heated by passage of electric current. The invention is now described by way of example with reference to the accompanying drawings in which:
Figures 1 and 2 represent plan views of alternative embodiments of a temperature sensor according to the invention; Figure 3 represents a plan view of a plurality of temperature sensors according to the invention produced as a batch on a single ceramic wafer, prior to separating the wafer into the individual sensors.
Referring to Figure 1, an embodiment of a temperature sensor according to the invention comprises a rectangular ceramic substrate 1, for example a 96% alumina ceramic substrate of about 0.25 mm thickness. An elongate film electrical resistance element 2 is adhered to a major surface of the substrate 1, adjacent an edge of the substrate. The resistance element 2 is formed of a material which has a large temperature co-efficient of resistance, e.g.
platinum or a cermet material containing platinum as the conducting phase. Suitably the resistance element 2 is provided by screen printing an appropriate composition onto the substrate 1 and firing at a high temperature. Suitable screenprintable compositions are known in the art e.g.
Type A3443 platinum ink manufactured by
Engelhard Minerals and Chemicals Corporation.
Film electrically conductive terminations 3 are also provided on the substrate and extend from the ends of the resistance element 2 to edge 4 of the substrate. The terminations 3 are suitably provided by screen printing an appropriate thick film conductor composition, e.g. Du Pont 6130
Palladium/Silver Conductor Composition, onto the substrate and firing at high temperature. In the arrangement shown in Figure 1 , the terminations 3 actually extend slightly underneath the ends of the resistance element 2, having been deposited on the substrate prior to the resistance element.
As an alternative however, the resistance element 2 could be deposited before the terminations, in which case the terminations would be arranged to overlie the ends of the resistance element 2.
An aperture 5 is provided through the substrate 1 adjacent the resistance element 2 and is dimensioned and arranged such that a narrow strip 6 of the substrate is effectively formed with the resistance element 2 adhered thereto. The aperture 5 is suitably formed by cutting through the substrate to remove an appropriate section, using a laser beam.
Referring now to Figure 2, a further embodiment of a temperature sensor according to the invention is provided in similar manner to that of Figure 1, i.e. comprising a ceramic substrate 1, a thick film resistance element 2, terminations 3 extending from the ends of the resistance element 2 to an edge 4 of the substrate 1, and an aperture 5 provided through the substrate 1. in the embodiment of Figure 2, however, a second resistance element 7 is provided on the substrate 1 and located adjacent an edge of the aperture 5 opposite resistance element 2.
Film electrically conductive terminations 8 are provided on the substrate and extend from the ends of the resistance element 7 to edge 4 of the substrate 1. The resistance element 7 and its terminations 8 may suitably be formed of the same materials as and simultaneously with resistance element 2 and terminations 3. A second aperture 9, similar to aperture 5 is formed in the substrate 1 adjacent resistance element 7, e.g. by cutting through the substrate using a laser beam.
The aperture 9 is dimensioned and arranged with respect to the second resistance element 7 such that a further narrow strip 10 of substrate is formed (similar to the strip 6) with the second resistance element 7 adhered thereto.
In the embodiments shown in Figures 1 and 2, the film resistance elements and terminations may be protected by means of a suitable electrically insulating coating, the coating being arranged to terminate as shown at the dotted line 11, so that the portions of the terminations in the region of the edge 4 of the substrate remain unprotected.
With the use of resistance elements and termination based on screen-printed and fired thick film compositions an appropriate protective coating is a glaze, which may conveniently be applied by screen printing and firing a suitable composition such as, for example, Du Pont 9137
Thick Film Resistor Encapsulation.
Figure 3 illustrates a preferred manufacturing process for the production of temperature sensors according to the invention. A wafer 1A of the same type of ceramic material described for the substrate 1 in Figures 1 and 2 has a plurality of temperature sensors formed thereon comprising temperature sensitive film electrical resistance elements 2 and film electrically conductive terminations 3. All of the resistance elements 2 are formed together by the same operation; likewise all of the terminations 3. The materials and processes used for forming the resistance elements and terminations by the preferred technique of screen printing and firing are as described earlier with reference to Figures 1 and 2.Apertures 5 are formed through the wafer 1 A by removing appropriate portions of the wafer 1A using a laser beam, the dimensions and location of each aperture with respect to its adjacent resistance element 2 being as previously described with reference to Figure 1. The wafer is then cut or fractured as indicated along the dotted lines 12, 13 and 14 to separate individual temperature sensors from the wafer, each sensor being based on a substrate formed by a portion of the wafer 1A, such a substrate being represented by reference numeral 1 in Figures 1 and 2.
If desired, a protective electrically insulating coating may be applied to cover the resistance elements and appropriate portions of the terminations, prior to separating the wafer into the individual temperature sensors. As mentioned above, sucha coating may conveniently comprise a screen-printed and fired glaze composition.
The temperature sensors illustrated in Figures 1 and 2 are particularly suitable for use in anemometers for monitoring fluid flow, e.g. air flow. They are especially applicable where a matched pair of resistance elements is necessary for locating in a fluid stream. One of the elements is used to provide a reference resistance for ambient temperature and the other element is arranged to be heated by passage through it of an electric current, measurement of the electric current required to maintain the resistance element at a predetermined temperature above the ambient level being used to give a measure of the fluid flow.In this respect, two of the sensors illustrated in Figure 1 may be located in a fluid stream to be monitored, the resistance element 2 of one sensor being used as a reference for indicating the ambient temperature, the resistance element 2 of the other sensor being arranged to be heated by passing an electric current through it.
The two sensors would normally be arranged to be spaced apart and offset in the fluid stream. For this purpose, two sensors having closely matched parameters would preferably be used. Suitably these sensors would have been manufactured in end-to-end relationship in the process illustrated in Figure 3; i.e. they could comprise sensors X and
Y in Figure 3 after separation.
Instead of using two sensors to monitor fluid flow, the single sensor of Figure 2 having two resistance elements thereon may be employed.
One resistance element (e.g. element 7) may be used as a reference for ambient temperature and the other resistance element (i.e. element 2) may be heated by passing an electric current through it as described above.
A particular application of the sensor of the invention is for the measurement of mass air flow in the induction manifold of an internal combustion engine.
The construction of the temperature sensor of the invention is particularly advantageous in that the provision of the apertures 5 and 9 minimises the thermal mass of the sensor.
Claims (22)
1. A temperature sensor comprising: a ceramic substrate; an elongate film electrical resistance element adhered to a major surface of said substrate adjacent an edge thereof, said element having an electrical resistance value which changes significantly with temperature over a predetermined temperature range; film electrically conductive terminations adhered to said substrate and extending from said resistance element; an aperture provided through said substrate adjacent said resistance element, said aperture being dimensioned and arranged such that a narrow strip of said substrate is formed with said resistance element adhered thereto.
2. A temperature sensor according to Claim 1 in which a second elongate film electrical resistance element and terminations therefor are provided adhered to said substrate either on said major surface of said substrate or on an opposite major surface of said substrate.
3. A temperature sensor according to Claim 2 in which said second resistance element is located adjacent on edge of said aperture, a second aperture being provided through said substrate adjacent said second resistance element, said second aperture being dimensioned and arranged with respect to said second resistance element such that a further narrow strip of said substrate is formed with said second resistance element adhered thereto.
4. A temperature sensor according to Claim 1,
2 or 3 in which said aperture. and said further
aperture where provided, has or have been formed
by cutting said substrate by means of a laser
beam.
5. A temperature sensor according to Claim 4
in which said aperture, and said further aperture
where provided, has or have been formed after
providing said resistance element or elements.
6. A temperature sensor according to any one of the preceding Claims in which said resistance element or elements comprises or comprise a thick film resistor material.
7. A temperature sensor according to Claim 6 in which said resistance element or elements has or have been provided by screen printing and firing a suitable thick film resistor composition.
8. A temperature sensor according to Claim 6 or 7 in which said thick film resistor composition comprises a cermet composition or a metal
resinate composition.
9. A temperature sensor according to any one of the preceding Claims in which said resistance element(s) comprise(s) or include(s) platinum.
10. A temperature sensor according to any one of the preceding Claims in which the said terminations for said resistance element or elements extend to an edge of said substrate.
11. A temperature sensor according to any one of the preceding Claims in which said terminations comprise a thick film conductive material.
12. A temperature sensor according to Claim
11, in which said terminations have been provided by screen printing and firing a suitable thick film conductor composition.
13. A temperature sensor accbrding to any one of the preceding Claims in which a coating of electrically insulating material is provided overlying said resistance element or elements.
14. A temperature sensor according to Claim 13 in which said coating is also arranged to overlie at least part of said terminations.
1 5. A temperature sensor according to Claim 13 or 14 in which said coating comprises a glaze.
1 6. A temperature sensor according to Claim 1 5 in which said glaze has been formed by screen printing and firing a suitable composition onto said sensor.
17. A temperature sensor according to any one of the preceding Claims which has been provided as one of a plurality of such sensors, said plurality of sensors having been formed by a single sequence of operations on a wafer of ceramic material, said ceramic material having been suitably cut or fractured to separate each said temperature sensor.
18. A temperature sensor according to Claim 1 7 in which said wafer of ceramic material has been cut by means of a laser beam.
19. A temperature sensor constructed and arranged substantially as herein described with reference to the accompanying drawings.
20. Apparatus for use in fluid flow measurement comprising or including a temperature sensor according to any one of the preceding Claims.
21. Apparatus according to Claim 20 embodied in an anemometer.
22. Apparatus according to Claim 21 for use in the measurement of mass air flow in an intake manifold of an internal combustion engine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08212717A GB2120453B (en) | 1982-04-30 | 1982-04-30 | Temperature sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08212717A GB2120453B (en) | 1982-04-30 | 1982-04-30 | Temperature sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2120453A true GB2120453A (en) | 1983-11-30 |
| GB2120453B GB2120453B (en) | 1985-09-11 |
Family
ID=10530123
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08212717A Expired GB2120453B (en) | 1982-04-30 | 1982-04-30 | Temperature sensor |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2120453B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1991001561A1 (en) * | 1989-07-25 | 1991-02-07 | Roth-Technik Gmbh & Co. Forschung Für Automobil- Und Umwelttechnik | Temperature sensor and process for producing the same |
| EP0437325A3 (en) * | 1990-01-08 | 1991-08-14 | General Electric Company | Temperature sensors |
| DE4445243A1 (en) * | 1993-12-27 | 1995-06-29 | Ngk Insulators Ltd | Temperature sensor |
| WO2012052514A3 (en) * | 2010-10-21 | 2012-09-07 | Continental Automotive Gmbh | Temperature sensor device |
| CN107219015A (en) * | 2017-04-17 | 2017-09-29 | 捷开通讯(深圳)有限公司 | A kind of mobile terminal |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2052859A (en) * | 1979-05-23 | 1981-01-28 | Heidenhain Gmbh Dr Johannes | Bolometer |
-
1982
- 1982-04-30 GB GB08212717A patent/GB2120453B/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2052859A (en) * | 1979-05-23 | 1981-01-28 | Heidenhain Gmbh Dr Johannes | Bolometer |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1991001561A1 (en) * | 1989-07-25 | 1991-02-07 | Roth-Technik Gmbh & Co. Forschung Für Automobil- Und Umwelttechnik | Temperature sensor and process for producing the same |
| US5202665A (en) * | 1989-07-25 | 1993-04-13 | Roth-Technik Gmbh & Co. | Temperature sensor and process for its production |
| EP0437325A3 (en) * | 1990-01-08 | 1991-08-14 | General Electric Company | Temperature sensors |
| DE4445243A1 (en) * | 1993-12-27 | 1995-06-29 | Ngk Insulators Ltd | Temperature sensor |
| US5823680A (en) * | 1993-12-27 | 1998-10-20 | Ngk Insulators, Ltd. | Temperature sensor |
| DE4445243C2 (en) * | 1993-12-27 | 2002-03-21 | Ngk Insulators Ltd | temperature sensor |
| WO2012052514A3 (en) * | 2010-10-21 | 2012-09-07 | Continental Automotive Gmbh | Temperature sensor device |
| CN107219015A (en) * | 2017-04-17 | 2017-09-29 | 捷开通讯(深圳)有限公司 | A kind of mobile terminal |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2120453B (en) | 1985-09-11 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |