Free charge carrier diffusion response transducer for sensing gradients
First Claim
1. A gradient-sensing 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;
wherein the transducer material has an energy gap in its charge carrier energy states which energy gap is sensitive to the property, and a gradient in the property creates a corresponding gradient in the energy gap, which in turn creates a gradient in concentration of free charge carriers including electrons and holes, resulting in a diffusion flow of the free charge carriers from regions of higher concentrations to regions of lower concentrations, whereby a net electric diffusion current results due to a difference in mobilities of free charge carriers of opposite electrical charge;
a pair of electrodes coupled to the transducer material;
no applied or external magnetic field source having a vector field component perpendicular to a line connecting the pair of electrodes; and
a measuring device electrically coupled to the pair of electrodes, wherein the measuring device is adapted to produce an output indicative of the gradient based on diffusion current density, or voltage associated with the diffusion current density, between the pair of electrodes in the transducer material.
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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.
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Citations
23 Claims
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1. A gradient-sensing transducer comprising:
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a transducer material passively responsive to a gradient of a property of a medium in which a portion of the transducer is disposed;
wherein the transducer material has an energy gap in its charge carrier energy states which energy gap is sensitive to the property, and a gradient in the property creates a corresponding gradient in the energy gap, which in turn creates a gradient in concentration of free charge carriers including electrons and holes, resulting in a diffusion flow of the free charge carriers from regions of higher concentrations to regions of lower concentrations, whereby a net electric diffusion current results due to a difference in mobilities of free charge carriers of opposite electrical charge;a pair of electrodes coupled to the transducer material; no applied or external magnetic field source having a vector field component perpendicular to a line connecting the pair of electrodes; and a measuring device electrically coupled to the pair of electrodes, wherein the measuring device is adapted to produce an output indicative of the gradient based on diffusion current density, or voltage associated with the diffusion current density, between the pair of electrodes in the transducer material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for sensing a gradient in a medium comprising:
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disposing a gradient transducer in a medium, said gradient transducer being capable of making a single-transducer measurement of a local gradient;
wherein the transducer is made of a material that has an energy gap in its charge carrier energy states which energy gap is sensitive to the property, and a gradient in the property creates a corresponding gradient in the energy gap, which in turn creates a gradient in concentration of free charge carriers including electrons and holes, resulting in a diffusion flow of the free charge carriers from regions of higher concentrations to regions of lower concentrations, whereby a net electric diffusion current results due to a difference in mobilities of free charge carriers of opposite electrical charge, wherein no external magnetic field is applied to the gradient transducer;measuring a diffusion current density, or a voltage associated with the diffusion current density, in the transducer; and associating the measured diffusion current density or voltage with a pressure gradient, or a temperature gradient, or a gradient of another physical property in the medium. - View Dependent Claims (19, 20)
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21. A system for marine seismic survey comprising:
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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, absent an applied or external magnetic field, indicative of a gradient of a property of a medium in which the gradient transducer is disposed, based on a diffusion current density within the gradient transducer; wherein the gradient transducer is made of a material that has an energy gap in its charge carrier energy states which energy gap is sensitive to the property, and a gradient in the property creates a corresponding gradient in the energy gap, which in turn creates a gradient in concentration of free charge carriers including electrons and holes, resulting in a diffusion flow of the free charge carriers from regions of higher concentrations to regions of lower concentrations, whereby a net electric diffusion current results due to a difference in mobilities of free charge carriers of opposite electrical charge; and wherein the gradient transducer includes at least one pair of electrodes to collect the diffusion current and a measuring device electrically coupled to the at least one pair of electrodes, wherein the measuring device is adapted to produce an output indicative of the gradient based on the diffusion current density, or voltage associated with the diffusion current, between the at least one pair of electrodes in the gradient transducer. - View Dependent Claims (22, 23)
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Specification