Measurement of lens characteristics
US5469261A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 6, 1994 |
| Grant date | Nov 21, 1995 |
| Priority date | — |
| Expiry date | Sep 6, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B2290/15
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Method and apparatus for measuring the following lens characteristics: (a) curvature of the front and back surfaces of the lens; (b) physical thickness; and (c) index of refraction of the lens to determine the front vertex power, back vertex power; and the lens material. In particular, an embodiment of one aspect of the present invention for measuring the index of refraction of the glass includes: (a) a source of a substantially spatially coherent beam of radiation and having a short temporal coherence length; (b) a beamsplitter to provide a sample beam and a reference beam in response to the beam; (c) a translatable retroreflector which reflects the reference beam; (d) a holder to hold the material in the path of the sample beam, the holder including a retroreflector which reflects the sample beam back through the material and a caliper apparatus to measure the thickness of the material where the sample beam passes through; (e) a detector which detects the reflected reference beam and the reflected sample beam to produce a detector output signal; and (f) an analyzer which determines a position of the translatable retroreflector in response to the detector output signal and which d…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.