Patent attributes
An unpolarized light beam emitted from a target presenting light source (12) is collimated by a collimator lens (20), and is made to be incident on a target presenting liquid crystal shutter (22), while an unpolarized light beams emitted from a background presenting light source (14) is collimated by a collimator lens (30), and is made to be incident on a background presenting liquid crystal shutter (32). The liquid crystal shutters (22, 32) have shutter patterns which are reverses to each other. The target and background light beams emerging from said liquid crystal shutters (22, 32) are combined with each other, together with their polarization states, by a half prism (24) acting as combining means. The resultant unpolarized light beam resulting from the combining is projected through a magnifying optical system (26) onto an eye to be examined. Since an unpolarized light beam is projected onto the eye, reliable examination, unaffected by polarization, can be realized.
