Patent · US Expired

Optical surface flatness measurement apparatus

US5383025A · kind A · utility

6Cited by
2References
17Claims
0Family size

Assignee

Inventor

Key dates

Filing dateDec 23, 1992
Grant dateJan 17, 1995
Priority date
Expiry dateDec 23, 2012

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG01B11/306
  • WIPO fieldMeasurement
  • WIPO sectorInstruments

Abstract

The flatness of at least a portion of a substantially planar surface (16) is measured by illuminating the surface through a beam splitter (12) incorporating a grid (13) or other patterned shield. The light pattern reflected from the surface (16) is directed by way of a reflector (14) back through the beam splitter (12) and thus through the grid (13). The image exiting the beam splitter (12) has characteristics representative of the flatness of the surface.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.