Optically stimulated differential impedance spectroscopy
First Claim
1. A method of evaluating a fluid material selected from the group consisting of:
- biomedical fluids, organic dielectric fluids, refrigerants, electrochemical fluids, and industrial process fluids comprising;
measuring a first electrical impedance of the fluid material at one or more frequencies greater than 65 kHz under a first state of illumination;
measuring a second electrical impedance of the fluid material at one or more frequencies greater than 65 kHz under a second state of illumination that is different from the first state of illumination;
and evaluating the fluid material based upon a difference between the first electrical impedance and the second electrical impedance.
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Accused Products
Abstract
Methods and apparatuses for evaluating a material are described. Embodiments typically involve use of an impedance measurement sensor to measure the impedance of a sample of the material under at least two different states of illumination. The states of illumination may include (a) substantially no optical stimulation, (b) substantial optical stimulation, (c) optical stimulation at a first wavelength of light, (d) optical stimulation at a second wavelength of light, (e) a first level of light intensity, and (f) a second level of light intensity. Typically a difference in impedance between the impedance of the sample at the two states of illumination is measured to determine a characteristic of the material.
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Citations
19 Claims
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1. A method of evaluating a fluid material selected from the group consisting of:
- biomedical fluids, organic dielectric fluids, refrigerants, electrochemical fluids, and industrial process fluids comprising;
measuring a first electrical impedance of the fluid material at one or more frequencies greater than 65 kHz under a first state of illumination; measuring a second electrical impedance of the fluid material at one or more frequencies greater than 65 kHz under a second state of illumination that is different from the first state of illumination; and evaluating the fluid material based upon a difference between the first electrical impedance and the second electrical impedance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- biomedical fluids, organic dielectric fluids, refrigerants, electrochemical fluids, and industrial process fluids comprising;
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9. An apparatus for evaluating a fluid material selected from the group consisting of:
- biomedical fluids, organic dielectric fluids, refrigerants, electrochemical fluids, and industrial process fluids comprising;
an impedance sensor system configured to measure impedance of the fluid material at one or more frequencies greater than 65 kHz; a source of optical stimulation configured to expose the fluid material to at least two different states of illumination; and a control system configured to; (1) switch the source of optical stimulation between the at least two different states of illumination, and (2) trigger the impedance sensor system to measure the impedance of the fluid material at each of the at least two different states of illumination. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
- biomedical fluids, organic dielectric fluids, refrigerants, electrochemical fluids, and industrial process fluids comprising;
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18. An apparatus for evaluating a fluid material selected from the group consisting of:
- biomedical fluids, organic dielectric fluids, refrigerants, electrochemical fluids, and industrial process fluids comprising;
an impedance sensor system configured to measure impedance of the fluid material, the impedance sensor system including a pattern of interdigitated electrodes disposed on a printed circuit board; a source of optical stimulation configured to expose the fluid material to at least two different states of illumination; a control system configured to; (1) switch the source of optical stimulation between the at least two different states of illumination, and (2) trigger the impedance sensor system to measure the impedance of the fluid material at each of the at least two different states of illumination; and
a test port window that is at least partially transparent to the optical stimulation, the test port window having a surface that is disposed adjacent and substantially parallel to the printed circuit board, wherein the fluid material is disposed between and in contact with the printed circuit board and the surface of the test port window.
- biomedical fluids, organic dielectric fluids, refrigerants, electrochemical fluids, and industrial process fluids comprising;
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19. A method for evaluating oil used for lubrication comprising:
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measuring a first electrical impedance of the oil while exposing the oil to substantially no optical stimulation; measuring a second electrical impedance of the oil while exposing the oil to substantial optical stimulation; determining that the second electrical impedance is different from the first electrical impedance by an impedance differential; and comparing the impedance differential with a reference impedance differential standard to estimate how long the oil has been in service.
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Specification