Sheet conductance/resistance measurement system

摘要

An apparatus for testing of electrical or physical properties of a material include a single coil sensor mounted adjacent to a sample of the material. Sheet conductance of a wide variety of materials may be measured using the single coil to determine if the material conforms to generally accepted standards for the use to which the material will be put. In some examples, the material is a semiconductor wafer or flat panel. In other examples, the material is the body tissue of a patient. A non-invasive technique using the apparatus is also disclosed for monitoring the health of patient tissue such as musculature, and/or to determine whether healthy circulation is present, by measuring the conductance of the patient tissue in response to a magnetic field applied by the single coil. The single coil may be hand held, or it may be movable using an automated positioning system under computer control.

主权项

1. A method for measuring conductance of a sample, comprising:
providing a coil, an oscillator connected to the coil for applying a voltage to the coil to induce a magnetic field, and an automatic gain control circuit connected to the oscillator; positioning said coil adjacent a sample to be measured; subjecting the sample to a magnetic field produced by said coil; detecting a change in voltage due to the presence of said sample in said magnetic field; converting said voltage change to a conductance value for said sample; and comparing said conductance value to a standard conductance value to determine whether said conductance value is within a predetermined acceptable range, wherein the sample has a contoured surface, the method further comprising the step of moving the coil along the contoured surface of the sample while maintaining a predetermined gap distance between the coil and the contoured surface being measured.