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Probe for measuring surface roughness by sensing fringe field capacitance effects

  • US 5,270,664 A
  • Filed: 05/19/1992
  • Issued: 12/14/1993
  • Est. Priority Date: 10/03/1990
  • Status: Expired due to Fees
First Claim
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1. A probe for measuring a surface roughness profile of a surface of a body along a measurement direction across the surface, the probe comprising;

  • a pair of electrodes; and

    an electric circuit comprising means for determining the effect of the surface on a capacitance between the pair of electrodes as the probe is moved over the surface, wherein the pair of electrodes comprise thin plates mounted confronting each other in a spaced apart relationship, surface planes of the pair of electrodes being parallel to each other and substantially normal to the surface as the probe is moved a layer of electrical insulating material being provided between the pair of electrodes, and a total distance across the two electrodes including the insulating material therebetween being in the range of 0.1 to 10 microns.

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