Tokyo Kogaku Kikai Kabushiki Kaisha

Mitsugu Aoki

Taketoshi Ishihara

Yasuo Kato

Yoshinori Oana

Yoshikazu Konishi

An ophthalmic instrument having a cylindrical test lens and a cross cylinder lens which are adapted to be placed in an examining optical path. The cross cylinder lens is mounted on a lens tube which is rotatably mounted on a swingable lever about a pivot axis. A gear train is provided between the lens tube for the cross cylinder lens and a rotatable part for rotating the cylindrical test lens so that the cylinder axis of the cylindrical lens be rotated about the optical axis of the examining optical path by rotating the lens tube.

Ophthalmic instrument having a cross cylinder lens

A vision testing instrument has a projecting optical system for projecting a test chart to produce an aerial image. In the optical system, there is provided a focusing reflector for producing a chart image at a far point. A second focusing reflector is provided so that it can be retractably inserted into the projecting optical path for producing a chart image at a near point.

Vision testing instrument

Ophthalmometer comprising a chart projecting optical system for projecting a Landolt type inspection chart and a lens means for locating a corrective lens in the projecting light path. A manually operated switch is provided for actuation by a patient. A mark is presented and moved around the projected chart image for the purpose of having the patient actuate the switch when the mark is at a position corresponding to the slit of the chart. When the switch is actuated at a correct time, the chart advanced by one step but when the switch is actuated at an incorrect timing the lens of next larger dioptral valve is placed in the projecting light path.

Ophthalmometer

Ophthalmic examination chart projector including a rotatable chart carrying disc and a mask plate which are co-axial with each other. A light source and a projecting lens assembly are provided for projecting one of the charts on the disc and one of the mask openings onto a screen. An index tube is rotatably mounted in the projecting optical path and carrying a colored filter on the inner periphery thereof. Thus, an astigmatic index can be projected on the peripheral portion of the astigmatic examination chart. The chart carrying disc, the mask plate and the astigmatic index tube can be controlled by knobs all provided on the front panel of the projector.

Growing community of inventors

Tokyo, Japan

Mitsugu Aoki