The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 31, 1989
Filed:
Aug. 10, 1987
ALPS Electric Co., Ltd., , JP;
Abstract
An optical position input device wherein an influence of disturbant light can be practically eliminated. The device includes a large number of light emitting elements and a large number of light receiving elements arranged in an opposing relationship along two sides and the other two sides, respectively, of directions of the X- and Y-axes. During driving scanning of the light emitting elements and the light receiving elements in the direction of the X-axis, a light reception signal developed in response to incident disturbant light from a selected one of the light receiving elements in the direction of the Y-axis is stored into a memory, and then the light reception signal is subsequently read out from the memory and is subtracted on a subtractor from a light reception signal developed from a light receiving element selected upon driving scanning for the direction of the Y-axis. The subtractor thus provides a position signal from which an influence of disturbant light has been eliminated assuredly. An influence of disturbant light is eliminated in a similar manner from a light reception signal developed from a light receiving element in the direction of the X-axis.