Free Charge Carrier Diffusion Response Transducer For Sensing Gradients

• US 20110194376A1
• Filed: 10/09/2009
• Published: 08/11/2011
• Est. Priority Date: 11/21/2008
• Status: Active Grant

• Current Assignee: Gary A. Hallock, Mark A. Meier
• Original Assignee: Gary A. Hallock, Mark A. Meier
• Inventors: Hallock, Gary A., Meier, Mark A.
• Granted Patent: US 8,681,586 B2
• Time in Patent Office: Days
• US Class Current: 367/15
• CPC Class Codes: G01D 5/18 by varying effective impedance of discharge tubes or semiconductor devices
• CPC Class Codes: G01H 9/00 Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
• CPC Class Codes: G01K 3/14 in respect of space
• CPC Class Codes: G01K 7/00 Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat giving results other than momentary value of temperature G01K3/00 ; Power supply therefor, e.g. using thermoelectric elements
• CPC Class Codes: G01V 1/186 Hydrophones
• CPC Class Codes: G01V 1/189 Combinations of different types of receiving elements

Abstract

Devices for sensing gradients are constructed from material whose properties change in response to gradients. One embodiment of the device is a transducer (200) for sensing gradients that includes the material (210) and two or more electrodes (240, 270) coupled to the material. In one embodiment, gradients in a surrounding medium (110) modify the energy gap of the material in the transducer (130) producing a diffusion current density (150). The material is configured to connect to a current or voltage measurement device (520, 530, 540) where a measurement is used to determine the gradient in the medium (160). The devices can be used to measure pressure, temperature, and/or other properties. The transducer can be built on the same substrate as complementary circuitry. A transducer made of Indium. Antimonide is used in marine seismology to measure pressure gradients.

Claims

1. A transducer comprising:

a transducer material passively responsive to a gradient of a property of a medium in which a portion of the transducer is disposed;

a plurality of electrodes coupled to the transducer material; and

a measuring device electrically coupled to the plurality of electrodes, wherein the measuring device is adapted to produce an output indicative of the gradient based on a diffusion current density in the transducer material.

2. The transducer of claim 1, wherein the measuring device is a current measurement device that provides the output indicative of the gradient as a function of current measured between at least two of the plurality of electrodes.

3. The transducer of claim 1, wherein the measuring device is a voltage measurement device that provides the output indicative of the gradient as a function of voltage measured between at least two of the plurality of electrodes.

4. The transducer of claim 1, wherein the measuring device is a diffusion current density measurement device that provides output indicative of the gradient.

5. The transducer of claim 1, wherein the transducer material is a semiconductor.

6. The transducer of claim 5, wherein the semiconductor is an intrinsic semiconductor or a doped semiconductor.

8. The transducer of claim 1, wherein the transducer material is comprised of indium antimonide.

9. The transducer of claim 1, further comprising a waterproof and electrically insulating package enclosing the transducer material and the plurality of electrodes.

10. The transducer of claim 1, wherein a portion of the transducer is part of an integrated circuit.

11. The transducer of claim 10, further comprising an amplifier circuit adapted to increase a magnitude of a signal between at least two of the plurality of electrodes.

12. The transducer of claim 10, further comprising a filter adapted to increase the quality of a signal between at least two of the plurality of electrodes.

14. The transducer of claim 1 wherein the property of the medium is one of pressure and temperature.

15. The transducer of claim 1 wherein the plurality of electrodes comprises two electrodes disposed on opposite sides of the transducer material along a first direction.

16. The transducer of claim 1 wherein the plurality of electrodes comprises:

a first pair of electrodes disposed on opposite sides of the material along a first direction;

a second pair of electrodes disposed on opposite sides of the material along a second direction, wherein the second direction is different from the first direction; and

a third pair of electrodes disposed on opposite sides of the material along a third direction, wherein the third direction is different from the first direction and the second direction.

17. The transducer of claim 1 wherein the measuring device detects modifications of the diffusion current density in the transducer material that result from changes in the energy gap.

33. The transducer of claim 1, wherein the transducer material substantially comprises a solid having:

an energy gap, being an energy range where no electron states exist, wherein the energy gap is sensitive to the medium property;

electrons and holes as its free charge carriers; and

electron mobility μ

_e different from hole mobility μ

_h.

34. The transducer of claim 33, wherein the transducer material is selected based at least in part on the difference μ

_e−

μ

_h in electron and hole mobilities, wherein a larger difference means a larger diffusion current.

7. (canceled)

13. (canceled)

18. A method for sensing gradients in a medium comprising:

disposing at least one gradient transducer in a medium, wherein each of the at least one gradient transducer produces an output indicative of a gradient of a property based on a diffusion current density in a material of the at least one gradient transducer; and

using the output indicative of the gradient from at least one of the at least one transducer.

19. The method of claim 18, wherein the output indicative of the gradient is based on a measured current or a measured voltage within each of the at least one gradient transducer.

23. The method of claim 18, wherein disposing at least one gradient transducer in the medium comprises disposing at least three gradient transducers in the medium, wherein each of the at least three transducers provide output indicative of a gradient along different directions.

26. The method of claim 18, wherein using the outputs comprises one of recording the output indicative of the gradient from at least one of the at least one transducer, displaying the output indicative of the gradient from at least one of the at least one transducer, and providing the output indicative of the gradient as an input to other circuitry.

20-22. -22. (canceled)

24-25. -25. (canceled)

27. A system for marine seismic survey comprising:

a vessel;

a submerged towable platform adapted to be towed by the vessel under water and over a submerged area to be surveyed;

at least one receiver operably coupled to the submerged towable platform, the at least one receiver having a gradient transducer, wherein the gradient transducer produces an output indicative of a gradient of a property based on a diffusion current density of a material in which the gradient transducer is disposed.

28. The system of claim 27, wherein the at least one receiver further comprises at least one hydrophone.

29. The system of claim 27, wherein the receiver has a memory for storing the output from the gradient transducer.

30-32. -32. (canceled)