Corrective spectacle lens evaluating device - uses subjective refraction measurement, and automatically brings lenses before eye and displays combination using led and photodetector

摘要

The device uses two sets of discs, each disc (1..4) having a number of varying corrective lenses spaced around its periphery and the discs of each set being positioned one behind the other and rotatable. An IR LED system (6) with several lines of LED's arranged along spaced radii of an arc is positioned on one side of each set of discs, with a similar photodetector system at the opposite side of it. Each disc has spaced holes (25) around concentric code tracks (26..29), with each photodetector system (9..24) coupled to a storage matrix connected via a decoder and driver stage to a display.