Title:
MICRO-MACHINED THERMAL CONDUCTIVITY DETECTOR
Document Type and Number:
WIPO Patent Application WO/2000/058723
Kind Code:
A2
Abstract:
A micro-machined thermal conductivity detector for a portable gas chromatograph. The detector is highly sensitive and has fast response time to enable detection of the small size gas samples in a portable gas chromatograph which are in the order of nanoliters. The high sensitivity and fast response time are achieved through micro-machined devices composed of a nickel wire, for example, on a silicon nitride window (32) formed in a silicon member (31) and about a millimeter square in size. In addition to operating as a thermal conductivity detector, the silicon nitride window with a micro-machined wire therein of the device can be utilized for a fast response heater for PCR applications.
Inventors:
YU CONRAD
Application Number:
PCT/US2000/006614
Publication Date:
October 05, 2000
Filing Date:
March 14, 2000
Export Citation:
Assignee:
UNIV CALIFORNIA (US)
International Classes:
G01N25/18; G01N27/18; G01N30/02; G01N30/66; (IPC1-7): G01N30/66; G01N27/18
Foreign References:
| US4471647A | 1984-09-18 | |||
| EP0724151A1 | 1996-07-31 | |||
| DE19634690A1 | 1998-02-12 | |||
| US4935040A | 1990-06-19 | |||
| US3777366A | 1973-12-11 |
Other References:
DATABASE COMPENDEX [Online] ENGINEERING INFORMATION, INC., NEW YORK, NY, US YU CONRAD M ET AL: "High performance hand-held gas chromatograph" Database accession no. EIX99084522685 XP002141400 & PROCEEDINGS OF THE 1998 ASME INTERNATIONAL MECHANICAL ENGINEERING CONGRESS AND EXPOSITION;ANAHEIM, CA, USA NOV 15-20 1998, vol. 66, 1998, pages 481-486, ASME Dyn Syst Control Div Publ DSC;American Society of Mechanical Engineers, Dynamic Systems and Control Division (Publication) DSC; Micro-Electro-Mechanical Systems (MEMS) 1998 ASME, Fairfield, NJ, USA
TERRY S C ET AL: "A GAS CHROMOATOGRAPHIC AIR ANALYZER FABRICATED ON A SILICON WAFER" IEEE TRANSACTIONS ON ELECTRON DEVICES,US,IEEE INC. NEW YORK, vol. ED-26, no. 12, 1 December 1979 (1979-12-01), pages 1880-1886, XP000575133 ISSN: 0018-9383 cited in the application
TERRY S C ET AL: "A GAS CHROMOATOGRAPHIC AIR ANALYZER FABRICATED ON A SILICON WAFER" IEEE TRANSACTIONS ON ELECTRON DEVICES,US,IEEE INC. NEW YORK, vol. ED-26, no. 12, 1 December 1979 (1979-12-01), pages 1880-1886, XP000575133 ISSN: 0018-9383 cited in the application
Attorney, Agent or Firm:
Thompson, Alan H. (L-703 Livermore, CA, US)
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Claims:
THE INVENTION CLAIMED IS
| 1. | A thermal conductivity detector, comprising: a structure having an opening therein, a membrane located in said opening, and an electrical resistor formed on said membrane. |
| 2. | The detector of Claim 1, wherein said membrane is composed of silicon nitride. |
| 3. | The detector of Claim 2, wherein said membrane has a thickness in the range of about 1000A to lum. |
| 4. | The detector of Claim 2, wherein said electrical resistor is constructed in the form of a wire having a width of about 50 um. |
| 5. | The detector of Claim 4, wherein said wire is composed of material selected from the group consisting of nickel and gold. |
| 6. | The detector of Claim 2, wherein said structure is composed of silicon. |
| 7. | The detector of Claim 6, wherein said electrical resistor is composed of nickel. |
| 8. | The detector of Claim 7, wherein said silicon nitride membrane has a crosssection of about one millimeter. |
| 9. | The detector of Claim 1, in combination with a portable gas chromatograph wherein the size of gas samples passing therethrough are in the order of a nanoliter. |
| 10. | The detector of Claim 1, in combination with a sample separation column, wherein said structure of said detector is secured to said separation column such that sample and carrier gases passing through said separation column are directed through said membrane. |
| 11. | In a portable gas chromatograph, the improvement comprising: a highly sensitive, fast response time thermal conductivity detector, said detector including a silicon nitride window about a millimeter square, said window being provided with an electrical resistor constructed of a resistive wire material. |
| 12. | The improvement of Claim 11, wherein said resistive wire material is selected from the group consisting of nickel and gold. |
| 13. | The improvement of Claim 11, wherein said silicon nitride window is located in an opening of a structure, whereby sample and carrier gases may pass through said window and carry away thermal energy produced by said electrical resistor. |
| 14. | The improvement of Claim 13, wherein said structure is composed of silicon. |
| 15. | The improvement of Claim 14, wherein said resistive wire material is composed of nickel. |
| 16. | The gas chromatograph of Claim 11, being constructed to utilize gas samples of a size on the order of a nanoliter. |
Description:
INTERNATIONAL SEARCH REPORT Intemational Appiicatlon ho ,, US 00/06614 C.(Continuabon) DOCUMENTSCONSIDEREDTOBERELEVANT Category'Citahon ot oocument, wrth indica4on, wnere appropnate, of the robvant pasaages Relovant to claim No. X 4 US 4 471 647 A (JERMAN JOHN H ET AL) 1, 4,6, 18 September 1984 (1984-09-18) 8-10 the whole document X EP 0 724 151 A (YAMATAKE HONEYWELL CO LTD) 1,6,8-10 31 July 1996 (1996-07-31) page 5, line 9-line 26; figures 2-4 X DE 196 34 690 A (ENTEC UMWELTMESTECHNIK 1-3, 5-9 GMBH) 12 February 1998 (1998-02-12) the whole document X TERRY S C ET AL:"A GAS CHROMOATOGRAPHIC 1,3,5-9 AIR ANALYZER FABRICATED ON A SILICON WAFER" IEEE TRANSACTIONS ON ELECTRON DEVICES, US, IEEE INC. NEW YORK, vol. ED-26, no. 12, 1 December 1979 (1979-12-01), pages 1880-1886, XP000575133 ISSN: 0018-9383 cited in the application page 1883, left-hand column; figure 6 X US 4 935 040 A (GOEDERT MICHEL G) 1-3,5-9 19 June 1990 (1990-06-19) abstract; figures 9,10 column 4, line 61-column 5, line 15 column 7, line 26-column 9, line 22 X US 3 777 366 A (KIEFER M) 1,5,7-9 11 December 1973 (1973-12-11) column 5, line 43-column 8, line 68; figures 8,11 ) national application No. PCT/US 00/06614 INTERNATIONAL SEARCH " 00/06614 Box I Observations where certain claims were found unsearchable (Continuation of item 1 of first sheet) This Intemational Search Report has not been established in respect of certain claims under Article 17 (2) (a) for the foliowing reasons: 1. Claims Nos. : because they relate to subject matter not required to be searched by this Authonty, namely : 2. Claims Nos.: because they relate to parts of the Intemational Application that do not comply with the prescnbed requirements to such an extent that no meaningful international Search can be carried out, specifically : 3. Claims Nos : because they are dependent claims and are not drafted in accordance with the second and third sentences of Rule 6.4 (a). Box 11 Observations where unity of invention is lacking (Continuation of item 2 of first sheet) This Intemational Searching Authority found multiple inventions in this intemational application, as follows : 1. As a ! ! required additional search fees were timely paid by the applicant, this International Search Report covers all searchableclaims 2. As all searchable claims could be searched without effort justifying an additional fee, this Authonty did not invite payment of any additional fee. 3. As only some of the required additional search fees were timely paid by the applicant, this Intemational Search Report covers only those claims for which fees were paid, specifically claims Nos.: 4. g No required additionai search fees were timely paid by the applicant. Consequently, this International Search Report is restricted to the invention first mentioned in the claims ; it is covered by claims Nos.: 1-10 Remark on Protest The additional search fees were accompanied by the applicant's protest. U n No protest accompanied the payment of additional search fees. U FURTHER INFORMATION CONTINUE FROM PCT/ISA/210 1. Claim: Claims 1 to 10 a thermal conductivity detector comprising a membrane and an electrical resistor formed on said membrane, wherein the membrane is located in the opening of a structure.
2. Claim : Claims 11 to 16 a thermal conductivity detector comprising a membrane and an electrical resistor formed on said membrane, the thermal conductivity detector being part of a portable gas chromatograph, the membrane being made of silicon nitride and having a size of about a millimeter square. INTERNATIONAL SEARCH REPORT International ApplicaVOn No ormation on oatent family memders rC.., US 00/06614 Patent document Publication Patent famiiy Publication cited in search report date member (s) date US 4471647 A 18-09-1984 NONE EP 0724151 A 31-07-1996 JP 8201327 A 09-08-1996 AU 693301 B 25-06-1998 AU 4211896 A 01-08-1996 DE 69601953 D 12-05-1999 DE 69601953 T 02-12-1999 US 5756878 A 26-05-1998 DE 19634690 A 12-02-1998 NONE US 4935040 A 19-06-1990 NONE US 3777366 A 11-12-1973 CA 951538 A 23-07-1974 DE 2222617 A 30-11-1972 GB 1356334 A 12-06-1974 US 3704984 A 05-12-1972
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