Method and apparatus for detecting cosmetic defects in opthalmic lenses
US3988068A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 19, 1974 |
| Grant date | Oct 26, 1976 |
| Priority date | — |
| Expiry date | Dec 19, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/958
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Method and apparatus for detecting and analyzing cosmetic defects on the surface of ophthalmic lenses. The apparatus according to one embodiment comprises means for scanning a narrow beam of light across the lens surface under inspection together with an array of photodetectors for detecting the manner in which the scanning beam is scattered or deflected as a result of striking a defect on or beneath the lens surface. More particularly, the photodetector array is mounted around the edge of the lens in a symmetrical pattern such that by properly monitoring the outputs of the detectors and by correlating these outputs with the position of the scanning beam, information regarding the position of the defect, the type of defect, and its severity can readily be ascertained in an automatic manner. By properly positioning the detector array around the edge of the lens, the system is able to automatically distinguish between cosmetic defects on the surface being examined and any defects which may be present on the opposite lens surface as well as between actual cosmetic defects and external surface debris such as dust or fingerprints. By an alternative embodiment, the array of photodetector…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.