Lensometer with guided lens movement for progressive addition lens
US5303022A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 17, 1992 |
| Grant date | Apr 12, 1994 |
| Priority date | — |
| Expiry date | Jul 17, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M11/0228
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A computer indicated lens movement direction protocol is utilized in combination with a lensmeter to designate required movement of lenses with respect to a lensmeter to insure sequential measurement of progressive addition lenses. Lens measurement occurs at four sample points closely spaced on the lens surface. The system uses power variations (PV.sub.1 and PV.sub.2) at each of the spaced apart lens sampling points to indicate when sampling of the lens occurs in a region of constant spherical power, when sampling of the lens occurs in a region of changing spherical power, and finally when sampling again occurs in a region of constant and increased spherical power. When sampling of the lens occurs in a region of changing power, lens movement is guided along a path of constantly changing sphere utilizing changes in astigmatism measured in the 45.degree.-135.degree. directions (C.sub.X). A lens examination protocol is set forth with vector indicators setting forth the vertical direction required for movement as well as both desired left and right movement to maintain the shortest possible path between the respective lens portions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.