Median point detecting apparatus for a lensmeter
US4329049A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 6, 1980 |
| Grant date | May 11, 1982 |
| Priority date | — |
| Expiry date | Mar 6, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01M11/0228
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A lensmeter is disclosed for determining the refractive properties of a test lens, including an optical system to produce an ellipse of light at a detecting plane having information of such properties, a scanning linear photodiode array at the detecting plane for producing video output signals, a first integrator to integrate the video output signal from each photodiode, a compensator to compensate each video output signal for the light sensitivity of each photodiode, a second integrator to integrate the compensated video signals over the range of the distribution of light of an area of the ellipse being scanned, a circuit, connected to the second integrator, to detect the median point of the distribution, and a microprocessor to provide data identifying the median point in response to the detection.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.