Ocular parameter measuring device
US4591246A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 1983 |
| Grant date | May 27, 1986 |
| Priority date | — |
| Expiry date | Dec 20, 2003 |
Classification
- Technology area (CPC A)Human Necessities
- CPC primaryA61B3/111
- WIPO fieldMedical technology
- WIPO sectorInstruments
Abstract
A device (1) for measuring the ocular parameters of a subject is of conventional optical design, with a front panel (10), a convergent lens (11), an aiming hole (12) at the focus of the lens (11), and a light source (13) whose image in a semi-reflecting mirror (14) appears as a point at infinity. Liquid crystal matrixes are disposed in windows (15, 16, 17, 18) and controlled by a logic unit (20) connected to a control keyboard (21) and a display (22). Looking through the hole (12), the operator uses the keyboard (21) to send address signals from the logic unit (20) either to the columns of the top matrixes (15, 16) or to the lines of the top and bottom matrixes (15, 16, 17, 18). According to the operating modes selected, vertical lines appear in the top windows (15, 16) to measure the interpupillary distance or horizontal lines appear in all four windows for centering the lenses in the frame.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.