Asahi Kogaku Kogyo Kabushiki Kaisha

Hideyuki Ishiai

Masato Hara

Ikuzo Okamoto

Yukiyasu Nishikawa

Shuji Hoshika

Osamu Shindow

Kiyoshi Itoh

Shoji Kamasako

Masaaki Niiho

Hirochika Aiura

Norihiko Yoshimura

A method and apparatus for measuring eye refraction errors in which a plurality of infrared patterns are projected onto an eye to be measured. The reflected light is directed onto corresponding light sensitive detectors the outputs of which are coupled through bandpass filters, an automatic gain control circuit and an A/D converter to a microprocessor. The microprocessor analyses the digitized outputs calculating refraction powers in accordance with a disclosed nonlinear regression technique. The refraction errors of the eye, along with a reliability coefficient, are calculated in accordance with the thusly determined refraction powers.

Method and device for measuring eye refraction errors

An opthalmological instrument including a blinking detecting device for positively detecting when an eye is blinking to thereby eliminate errors in optical measurements due to variations in the signal light produced by the blinking. An optical system receives light beams reflected from a portion of an eye under examination to form an image of the front portion of the eye in an image plane. An image pickup element is disposed at the image plane and produces an output video signal in response thereto. A detecting circuit which receives the video signal determines whether or not the image pickup element exceeds a predetermined threshold value. If the threshold value is not exceeded, an indication is produced that blinking has occurred.

Device for detecting blinking of an eye under examination

A video signal composing circuit and method for aligning scanned CCD's in an optical reading device in which plural scanned CCD's are arranged in a line parallel to a reading surface. Clock pulses are counted which correspond to the scanning of the CCD's and compared with values set by plural switch groups. The outputs of the comparison circuits are coupled through a logic circuit which combines and gates the individual video output signals from the CCD's to produce a composite video signal which is free of overlap in video signals between adjacent CCD's.

CCD Scanner with improved resolution

Growing community of inventors

Tokyo, Japan

Hideyuki Ishiai