Calibration standard for optical gap measuring tools
US5724134A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 13, 1995 |
| Grant date | Mar 3, 1998 |
| Priority date | — |
| Expiry date | Nov 13, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/14
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus and means for calibrating optical gap-measuring instruments, including a preferred calibration standard (100) comprised of a substantially flat, transparent element (10) held in contact with the convex spherical surface (25) of a substantially opaque element (20) to provide an obvious and unambiguous region over which the gap is zero. The optical gap measuring tool that is to be calibrated is oriented so as to illuminate the interface. The calibration standard (100) is translated in position with respect the gap measuring tool in such a way as to vary the measured gap, while at the same time data storage means record the gap measurement as a function of relative position. This data is then compared to the predicted variation from the geometry of the calibration standard (100). Provided that the elements (10, 20) are of high optical quality, deviations of the measured data from an ideal parabolic curve are indicative of calibration errors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.