WO1992005432A1 - Integrated sensor - Google Patents
Integrated sensor Download PDFInfo
- Publication number
- WO1992005432A1 WO1992005432A1 PCT/EP1991/001845 EP9101845W WO9205432A1 WO 1992005432 A1 WO1992005432 A1 WO 1992005432A1 EP 9101845 W EP9101845 W EP 9101845W WO 9205432 A1 WO9205432 A1 WO 9205432A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- protruding portion
- sensing element
- heating element
- substrate
- sensor according
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
Definitions
- Sensors for measuring gas concentrations show a sensing element, a heating element and/or associated electronics at relatively short distances from each other. Electronics components are sensitive to temperature influences.
- US patent 4,413,502 discloses a sensor in which two substrates are combined together, a first one on which a sensing element is arranged and a second one which is provided with a heating element. It is an object of the present invention to provide an integrated sensor, in which heating and sensing elements are both provided on one substrate.
- the present invention provides a sensor comprising :
- first conductor paths connected on one end to said heating element and extending over the protruding portion; - first terminals ' fo .supplying electric current to the heating element, which are located opposite the protruding portion of the substrate and which are connected to the other ends of the first conductor paths extending over said protruding portion; - a sheet of insulating material provided over said heating element;
- Especially sub-claims 4-10 are directed to optimizing the sensitivity and/or heat-dissipation, viz the power efficiency, of the sensor according to the present invention.
- a sensor 1 comprises an insulating substrate 2, preferably of aluminium oxide (A1 2 0 3 ) , onto which is arranged a sensing element of a layer of tin oxide 3, or tin oxide doped with small amounts of additives (e.g. platinum) , under which ex ⁇ tend gold conductor paths 4 which are conductively connected via further conductor paths 6 of gold to solderable terminal contacts 7.
- the substrate 2 is preferably also provided with terminal contacts 8 for a heating element which is conductively connected via conductor paths 9, preferably of platinum, to a heating element (not further shown) which is deposited under a layer 11 of dielectric material.
- a sensor 1 is preferably disposed in a housing 12, for instance of plastic, and a cover 13, for instance of porous metal, fitting thereon.
- the conduction of the tin oxide gives, depending on the temperature, a measure for the concentration of gases in the air such as H / CH 4 etc.
- the surface of tin oxide can be taken to different temperatures, and a series of such elements held at different temperatures and/or with different tin oxide compositions (additives) can optionally be arranged. In this way, an array of sensors is constructed, yielding high selectivity.
- the insulating substrate is provided with a protruding portion on which the sensing element is arranged and the terminal contacts, optionally with electronics placed directly thereon, are placed at a distance from the protruding portion, the influences of temperature acting on the electronics via the terminal contacts remain minimal.
- the geometry of the protruding portion is optimalized in order to limit the amount of electric power dissipated by the heating element.
- the length of the protruding portion is such that the electrical resistance of the conductor paths 9 does not become too high, whereby the dissipation for these conductor paths 9 is increased.
- the protruding portion also cannot be too short.
- the width of the protruding portion can also be optimized with respect to thermal resistance and the electrical resistance of the conductor paths, which latter depends on the width thereof.
- the substrate has a thickness of 0,25 mm a width of about 1 mm and a length of about 8 mm.
- the preferred value for the width is to some extend increased relative to the optimal dimensions for the heattransfer, because of strength requirements for the protruding portion.
Abstract
A sensor (1) comprising: an insulating substrate (2) provided with a protruding portion; a heating element, arranged on said insulating substrate near the tip end of said protruding portion; first conductor paths (9) connected on one end to said heating element and extending over the protruding portion; first terminals (8) for supplying electric current to the heating element, which are located opposite the protruding portion of the substrate and which are connected to the other ends of the first conductor paths extending over said protruding portion; a sheet of insulating material provided over said heating element; a sensing element (3) arranged over said heating element near the tip end of said protruding portion; second conductor paths (4) connected on one end to the sensor element (3) and extending over said protruding portion; and second terminals (7) located opposite of said protruding portion of the substrate, and which are connected to the other ends of said second conductor paths and which are adapted for connecting one or more electronic circuits, which might be placed as a hybrid circuit in the same substrate.
Description
INTEGRATED SENSOR
Sensors for measuring gas concentrations, for instance polluting gases in air, show a sensing element, a heating element and/or associated electronics at relatively short distances from each other. Electronics components are sensitive to temperature influences.
US patent 4,413,502 discloses a sensor in which two substrates are combined together, a first one on which a sensing element is arranged and a second one which is provided with a heating element. It is an object of the present invention to provide an integrated sensor, in which heating and sensing elements are both provided on one substrate.
The present invention provides a sensor comprising :
- an insulating substrate provided with a protruding portion;
- a heating element, arranged on said insulating substrate near the tip end of said protruding portion;
- first conductor paths connected on one end to said heating element and extending over the protruding portion; - first terminals' fo .supplying electric current to the heating element, which are located opposite the protruding portion of the substrate and which are connected to the other ends of the first conductor paths extending over said protruding portion; - a sheet of insulating material provided over said heating element;
- a sensing element arranged over said heating element near the tip end of said protruding portion;
- second conductor paths connected on one end to the sensor element and extending over said protruding portion; and
- second terminals located opposite of said protruding portion of the substrate, and which are connected to the other ends of said second conductor paths and which are adapted for connecting one or more electronic circuits.
SUBSTITUTESHEET
The above mentioned component of the sensor can easily be disposed by means of thick-film techniques.
Especially sub-claims 4-10 are directed to optimizing the sensitivity and/or heat-dissipation, viz the power efficiency, of the sensor according to the present invention.
A doctor's thesis will be published in the forth coming year, in which proof for the formulas from the sub- claims can be found. Further advantages, features and details of the present invention will become apparent in the light of a description with reference to the annexed figure, wherein a sensor 1 comprises an insulating substrate 2, preferably of aluminium oxide (A1203) , onto which is arranged a sensing element of a layer of tin oxide 3, or tin oxide doped with small amounts of additives (e.g. platinum) , under which ex¬ tend gold conductor paths 4 which are conductively connected via further conductor paths 6 of gold to solderable terminal contacts 7. The substrate 2 is preferably also provided with terminal contacts 8 for a heating element which is conductively connected via conductor paths 9, preferably of platinum, to a heating element (not further shown) which is deposited under a layer 11 of dielectric material. As shown schematically, a sensor 1 is preferably disposed in a housing 12, for instance of plastic, and a cover 13, for instance of porous metal, fitting thereon.
The conduction of the tin oxide gives, depending on the temperature, a measure for the concentration of gases in the air such as H / CH4 etc.
Using the heating element and suitable calibration the surface of tin oxide can be taken to different temperatures, and a series of such elements held at different temperatures and/or with different tin oxide compositions (additives) can optionally be arranged. In this way, an array of sensors is constructed, yielding high selectivity.
SUBSTITUTESHEET
Since the insulating substrate is provided with a protruding portion on which the sensing element is arranged and the terminal contacts, optionally with electronics placed directly thereon, are placed at a distance from the protruding portion, the influences of temperature acting on the electronics via the terminal contacts remain minimal. In addition, the geometry of the protruding portion is optimalized in order to limit the amount of electric power dissipated by the heating element. In preference the length of the protruding portion is such that the electrical resistance of the conductor paths 9 does not become too high, whereby the dissipation for these conductor paths 9 is increased. On account of the above mentioned thermal resistance between the sensing element and the terminal contacts, the protruding portion also cannot be too short.
The width of the protruding portion can also be optimized with respect to thermal resistance and the electrical resistance of the conductor paths, which latter depends on the width thereof.
Preferably the substrate has a thickness of 0,25 mm a width of about 1 mm and a length of about 8 mm. The preferred value for the width is to some extend increased relative to the optimal dimensions for the heattransfer, because of strength requirements for the protruding portion.
SUBSTITUTESHEET
Claims
1. A sensor comprising :
- an insulating substrate provided with a protruding portion;
- a heating element, arranged on said insulating substrate near the tip end of said protruding portion;
- first conductor paths connected on one end to said heating element and extending over the protruding portion;
- first terminals for supplying electric current to the heating element, which are located opposite the protruding portion of the substrate and which are connected to the other ends of the first conductor paths extending over said protruding portion;
- a sheet of insulating material provided over said heating element; - a sensing element arranged over said heating element near the tip end of said protruding portion;
- second conductor paths connected on one end to the sensor element and extending over said protruding portion; and - second terminals located opposite of said protruding portion of the substrate, and which are connected to the other ends of said second conductor paths and which are adapted for connecting one or more electronic circuits, which might be placed as a hybrid circuit in the same substrate.
2. A sensor according to claim 1, in which said sensing element, said insulating sheet, said heating element, said conductor paths and/or said terminals, said electronic circuits are arranged using screen prints or thick-film technique.
3. A sensor according to claim 1 or 2, wherein the sensing element comprises a surface of tin oxide or tin oxide doped with small amounts of additives (e.g. platinum) .
4. A sensor according to claim 1,2 or 3, in which the dimensions of the surface area of the sensing element
SUBSTITUTE SHEET material is optimized by maximizing the change in temperature and thereby causes change in conductivity of the sensing element material, both of which changes are due to the presence of certain gases in the ambient.
5. A sensor according to claim 4, in which the change of temperature is based upon the formula
T> " -2 + •■-£,"£ " E <T3 - T2) -f2 + i-L-fc in which Ti is the temperature of the substrate near the tip end of the protruding portion; T2 is the ambient temperature of the surrounding in which the sensor is placed; a is a constant representing the power of the exotherm reaction per unit of surface area for the sensing element material; AT is the surface area between the sensing element and the ambient; A2 is the surface area between the substrate of the tip end and the ambient; hi is the heat transfer-coefficient between substrate and ambient; h2 is the heat transfer- coefficient between sensing element and ambient; T3 is the temperature of the sensing element and Qi is the power supplied to the heating element.
6. A sensor according to claim 4 or 5, in which the sensing element substantially extends over the complete width of said tip end of said protruding portion.
7. A sensor according to any of the foregoing claims, in which a layer of the same material as the material of said sensing element is arranged on the back side of said protruding portion near the tip end thereof.
8. A sensor according to ary one of the proceeding claims, in which the length of the protruding portion is optimized with respect to minimizing temperature gradient from tip end to the opposite side of the protruding portion and minimizing the length of the first conductor path connected to the heating element.
9. A sensor according to claim 8, in which the optimal length of the protruding portion is obtained from the following formula
L
P: = PT - k.f(p) + / pdl
0
SUBSTITUTESHEET in which P is the power dissipation of the sensor as a whole; PT is the power dissipated at the sensing element; k is the heat conduction coefficient of a cross section of the protruding portion; f(p) is a known function of the electrical power dissipation per unit length in the heater wires; L is the length of the protruding portion minus the
L length of the sensing element; J pdl can be determined from
0 the formula equation
10. A sensor according to any one of the proceeding claims, in which the thickness of the substrate is in the order of magnitude of 0,25 mm, the length is in the order of magnitude of 8 mm and the width is in the order of magnitude of 1 mm.
SUBSTITUTESHEET
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL9002077A NL9002077A (en) | 1990-09-22 | 1990-09-22 | SENSOR. |
| NL9002077 | 1990-09-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO1992005432A1 true WO1992005432A1 (en) | 1992-04-02 |
Family
ID=19857715
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/EP1991/001845 WO1992005432A1 (en) | 1990-09-22 | 1991-09-23 | Integrated sensor |
Country Status (2)
| Country | Link |
|---|---|
| NL (1) | NL9002077A (en) |
| WO (1) | WO1992005432A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6453723B1 (en) * | 1999-02-22 | 2002-09-24 | Ngk Spark Plug Co., Ltd. | Gas sensor device |
| US7304715B2 (en) | 2004-08-13 | 2007-12-04 | Asml Netherlands B.V. | Lithographic apparatus and device manufacturing method |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2061520A (en) * | 1979-10-20 | 1981-05-13 | Draegerwerk Ag | Hydrogen Sulphide Detector |
| US4413502A (en) * | 1981-04-27 | 1983-11-08 | Nippon Soken, Inc. | Gas detecting sensor |
| JPS58195146A (en) * | 1982-05-10 | 1983-11-14 | Nippon Soken Inc | Gaseous component detector |
| EP0101249A2 (en) * | 1982-08-06 | 1984-02-22 | Hitachi, Ltd. | Gas sensor |
| US4450428A (en) * | 1981-05-25 | 1984-05-22 | Nippon Soken, Inc. | Gas detecting sensor |
| EP0280540A2 (en) * | 1987-02-24 | 1988-08-31 | American Intell-Sensors Corporation | Method and apparatus for simultaneous detection of target gases in ambient air |
| EP0313390A2 (en) * | 1987-10-22 | 1989-04-26 | Kabushiki Kaisha Toshiba | Gas sensor and method for production thereof |
| EP0444753A1 (en) * | 1990-03-02 | 1991-09-04 | ENIRICERCHE S.p.A. | Method of determining gaseous hydrocarbons using gas sensors formed of thin tin oxide films |
-
1990
- 1990-09-22 NL NL9002077A patent/NL9002077A/en not_active Application Discontinuation
-
1991
- 1991-09-23 WO PCT/EP1991/001845 patent/WO1992005432A1/en unknown
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2061520A (en) * | 1979-10-20 | 1981-05-13 | Draegerwerk Ag | Hydrogen Sulphide Detector |
| US4413502A (en) * | 1981-04-27 | 1983-11-08 | Nippon Soken, Inc. | Gas detecting sensor |
| US4450428A (en) * | 1981-05-25 | 1984-05-22 | Nippon Soken, Inc. | Gas detecting sensor |
| JPS58195146A (en) * | 1982-05-10 | 1983-11-14 | Nippon Soken Inc | Gaseous component detector |
| EP0101249A2 (en) * | 1982-08-06 | 1984-02-22 | Hitachi, Ltd. | Gas sensor |
| EP0280540A2 (en) * | 1987-02-24 | 1988-08-31 | American Intell-Sensors Corporation | Method and apparatus for simultaneous detection of target gases in ambient air |
| EP0313390A2 (en) * | 1987-10-22 | 1989-04-26 | Kabushiki Kaisha Toshiba | Gas sensor and method for production thereof |
| EP0444753A1 (en) * | 1990-03-02 | 1991-09-04 | ENIRICERCHE S.p.A. | Method of determining gaseous hydrocarbons using gas sensors formed of thin tin oxide films |
Non-Patent Citations (1)
| Title |
|---|
| PATENT ABSTRACTS OF JAPAN vol. 8, no. 42 (P-256)(1479) 23 February 1984 & JP,A,58 195 146 ( NIPPON JIDOSHA BUHIN SOGO KENKYUSHO K.K. ) 14 November 1983 see abstract * |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6453723B1 (en) * | 1999-02-22 | 2002-09-24 | Ngk Spark Plug Co., Ltd. | Gas sensor device |
| US7304715B2 (en) | 2004-08-13 | 2007-12-04 | Asml Netherlands B.V. | Lithographic apparatus and device manufacturing method |
| US7804575B2 (en) | 2004-08-13 | 2010-09-28 | Asml Netherlands B.V. | Lithographic apparatus and device manufacturing method having liquid evaporation control |
| US9188880B2 (en) | 2004-08-13 | 2015-11-17 | Asml Netherlands B.V. | Lithographic apparatus and device manufacturing method involving a heater |
| US9268242B2 (en) | 2004-08-13 | 2016-02-23 | Asml Netherlands B.V. | Lithographic apparatus and device manufacturing method involving a heater and a temperature sensor |
| US10254663B2 (en) | 2004-08-13 | 2019-04-09 | Asml Netherlands B.V. | Lithographic apparatus and device manufacturing method involving a heater |
| US10838310B2 (en) | 2004-08-13 | 2020-11-17 | Asml Netherlands B.V. | Lithographic apparatus and device manufacturing method involving a heater |
| US11378893B2 (en) | 2004-08-13 | 2022-07-05 | Asml Netherlands B.V. | Lithographic apparatus and device manufacturing method involving a heater |
Also Published As
| Publication number | Publication date |
|---|---|
| NL9002077A (en) | 1992-04-16 |
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