Resistive thermal sensing

• US 7,473,031 B2
• Filed: 06/27/2005
• Issued: 01/06/2009
• Est. Priority Date: 04/01/2002
• Status: Expired due to Term

• Current Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Original Assignee: Palo Alto Research Center, Inc. (Xerox Holdings Corp.)
• Inventors: De Bruyker, Dirk, Peeters, Eric, Bell, Alan, Wolkin, Michal V.
• Primary Examiner(s): Verbitsky; Gail
• Assistant Examiner(s): Jagan; Mirellys
• Application Number:
  US11/167,748
• Publication Number:
  US 20050238080A1
• Time in Patent Office: 1,289 Days
• Field of Search: 374/31, 374/12, 422/51
• US Class Current: 374/31
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G01K 17/00 Measuring quantity of heat measuring temperature by calorimetry G01K3/00 - G01K11/00; specially adapted for measuring thermal properties of materials, e.g. specific heat, heat of combustion G01N
• CPC Class Codes: G01K 7/30 using thermal noise of resistances or conductors
• CPC Class Codes: G01N 25/482 concerning the temperature responsive elements measuring temperature or quantity of heat, thermally-sensitive elements G01K; thermoelectric devices H10N10/00, H10N15/00
• CPC Class Codes: G01N 25/4846 for a motionless, e.g. solid sample
• CPC Class Codes: G01N 25/4866 by using a differential method

Abstract

Thermal sensors for calorimetry can include vanadium oxide, heavily p-doped amorphous silicon, or other materials with high temperature coefficients of resistivity. Such thermal sensors can have low noise equivalent temperature difference (NETD). For example, a thermal sensor with NETD no greater than 100 μK over a bandwidth range of approximately 3 Hz or more can include a thermistor including vanadium oxide sputtered at room temperature under conditions that yield primarily V₂O₅; more specifically, the NETD can be no greater than 35 μK, or even 10 μK over a bandwidth range of approximately 3 Hz or more. If a low noise thermal sensor has NETD no greater than 50 μK over such a bandwidth range, a low noise output circuitry connected to its thermistor can provide an electrical output signal that includes information about input thermal signal peaks with amplitude of approximately 100 μK.

Claims

1. A calorimeter comprising:

a resistive thermometer element that includes vanadium oxide;

circuitry through which electrical resistance of the thermometer element can be detected; and

a structure with a reaction region in which reactions that produce thermal change occur, the structure conducting temperature from reactions in the reaction region to the thermometer element.

2. A calorimeter comprising:

a resistive thermometer element that includes vanadium oxide;

circuitry through which electrical resistance of the thermometer element can be detected; and

a structure with a reaction region in which reactions that produce thermal change occur, the structure conducting temperature from reactions in the reaction region to the thermometer element;

the reaction region and the thermometer element being spaced apart;

the structure further including a component with high thermal conductivity that is in thermal contact with the reaction region and with the thermometer element.

3. The calorimeter of claim 2 in which the thermometer element is made from thin film materials.

4. The calorimeter of claim 2 in which the vanadium oxide in the thermometer element has a high temperature coefficient of resistivity.

5. The calorimeter of claim 2 in which the reaction region is on a surface, the calorimeter further comprising a drop merging component that causes drops on the surface to merge in the reaction region.

6. A calorimeter comprising:

a thermal sensor that includes a thermistor, the thermistor including vanadium oxide;

the thermal sensor having noise equivalent temperature difference (NETD) not greater than approximately 100 μ

K over a bandwidth range of approximately 3 Hz or more under the calorimeter'"'"'s operating conditions;

a structure with a thermal conducting path that provides a thermal input signal to the thermistor;

the thermistor being on the structure;

the structure including;

a polymer layer; and

a barrier layer between the thermistor and the polymer layer; and

detecting circuitry connected to the thermal sensor, the detecting circuitry allowing electrical detection of information about the thermal input signal provided by the thermal conducting path.

7. The calorimeter of claim 6 in which the thermal sensor'"'"'s NETD is not greater than approximately 35 μ

K over a bandwidth range of approximately 3 Hz or more under the calorimeter'"'"'s operating conditions.

8. The calorimeter of claim 7 in which the thermal sensor'"'"'s NETD is not greater than approximately 10 μ

K over a bandwidth range of approximately 3 Hz or more under the calorimeter'"'"'s operating conditions.

9. A calorimeter comprising:

a set of one or more low noise thermistors;

each low noise thermistor having noise equivalent temperature difference not greater than approximately 50 μ

K over a thermal sensing bandwidth range of approximately 3 Hz or more under the calorimeter'"'"'s operating conditions;

a structure with one or more thermal conducting paths, each thermal conducting path providing a respective thermal input signal to a respective subset of the set of thermistors;

at least one thermistor in the subset including vanadium oxide;

each thermistor in the subset being on the structure;

the structure including;

a polymer layer; and

a barrier layer between the thermistors in the subset and the polymer layer; and

low noise detection circuitry connected to the set of thermistors, the detection circuitry allowing electrical detection of information about the thermal input signals provided by the thermal conducting paths.

10. The calorimeter of claim 9, further comprising output circuitry connected to the detection circuitry, the output circuitry electrically detecting information about the thermal input signals and, in response, providing an electrical output signal;

the electrical output signal being a time-varying signal that includes noise peaks with amplitudes not exceeding a maximum noise amplitude;

the electrical output signal also including signal peaks indicating information about the thermal input signal, each signal peak'"'"'s amplitude exceeding the maximum noise amplitude.

11. An array comprising:

not less than one calorimeter;

each calorimeter comprising;

a set of resistive thermometer elements, each including vanadium oxide;

circuitry through which electrical resistance of the thermometer elements can be detected; and

a structure with a reaction region in which reactions that produce thermal change occur, the structure conducting temperature from reactions in the reaction region to at least one of the thermometer elements;

the reaction region and the at least one thermometer element being spaced apart;

the structure further including a component with high thermal conductivity that is in thermal contact with the reaction region and with the at least one thermometer element.exceeding the maximum noise amplitude.

12. A calorimeter comprising:

a support structure that includes a polymer layer and a barrier layer;

a thermal sensor that includes one or more thermistors that are on the support structure with the barrier layer between the polymer layer and the thermistors, each of the thermistors including vanadium oxide; and

detecting circuitry electrically connected to the thermal sensor;

the support structure including at least one thermal conducting path that provides thermal input signals to at least one of the thermistors that are on the support structure, the detecting circuitry allowing electrical detection of information about the thermal input signals provided by the thermal conducting path.

13. The calorimeter of claim 12 in which the barrier layer includes silicon oxynitride.

14. The calorimeter of claim 12, further comprising one or more cells, each cell including a respective instance of the thermal sensor and the detecting circuitry;

each thermistor including primarily V₂O₅.

15. The calorimeter of claim 12, further comprising one or more cells, each cell including a respective instance of the thermal sensor and the detecting circuitry;

the barrier layer including silicon oxynitride.

16. The calorimeter of claim 12 in which the thermistor includes primarily V₂O₅.

17. The calorimeter of claim 16 in which the thermistor further includes one or more vanadium surface oxides other than V₂O₅.

18. A method of producing a calorimeter, comprising:

producing a resistive thermometer element, circuitry through which electrical resistance of the thermometer element can be detected, and a structure with a reaction region in which reactions that produce thermal change occur;

the structure conducting temperature from reactions in the reaction region to the thermometer element;

the reaction region and the thermometer element being spaced apart;

the structure further including a component with high thermal conductivity that is in thermal contact with the reaction region and with the thermometer element;

the act of producing the resistive thermometer element, the circuitry, and the structure comprising;

producing the resistive thermometer element to include vanadium oxide.

19. The method of claim 18 in which the resistive thermometer element includes primarily V₂O₅.

20. The method of claim 18 in which the act of producing the resistive thermometer element includes:

sputtering a metallic vanadium target material at room temperature in a plasma that includes oxygen.

21. A calorimeter comprising:

a set of one or more low noise thermistors;

each low noise thermistor having noise equivalent temperature difference not greater than approximately 50 μ

K over a thermal sensing bandwidth range of approximately 3 Hz or more under the calorimeter'"'"'s operating conditions;

a structure with one or more thermal conducting paths, each thermal conducting path providing a respective thermal input signal to a respective subset of the set of thermistors;

at least one thermistor in the subset including vanadium oxide;

each thermistor in the subset being on the structure;

the structure including;

a polymer layer; and

a barrier layer between the thermistors in the subset and the polymer layer; and

low noise output circuitry connected to the set of thermistors, the output circuitry electrically detecting information about the thermal input signals and, in response, providing an electrical output signal that includes detected information about the thermal input signals provided by the thermal conducting paths.

in which at least one of;

the thermal input signal of one of the thermal conductive paths has peaks with amplitude less than approximately 350 μ

K; and

the structure includes two or more of the thermal conductive paths and at least two of the respective thermal input signals have a difference between them, the electrical output signal including detected information about the difference.

22. The calorimeter of claim 21 in which the set of thermistors includes first and second subsets, each thermistor in the first subset receiving a first thermal input signal from a first one of the thermal conducting paths and each thermistor in the second subset receiving a second thermal input signal from a second one of the thermal conducting paths;

the electrical output signal including detected information about the difference between the first and second thermal input signals.

23. The calorimeter of claim 21 in which the thermal input signal of one of the thermal conducting paths includes peaks with amplitude less than approximately 350 μ

K;

the electrical output signal including signal peaks indicating detected information about at least one of the peaks with amplitude less than approximately 350 μ

K.

24. The calorimeter of claim 21 in which the peaks in the thermal input signal of the one of the thermal conducting paths include a subset of peaks with amplitude of approximately 100 μ

K;

the electrical output signal including signal peaks indicating detected information about at least one of the peaks in the subset.