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:
Apr. 21, 1998
Filed:
May. 24, 1996
Seiko Precision Inc., , JP;
Abstract
In order to improve the accuracy and reliability of a distance measurement device of the light-projecting type, the device is provided with a reference voltage generator for generating a reference voltage having a level dependent upon whether or not a light is being projected. The distance measurement device includes a light projecting circuit for projecting pulsed light onto an object, a light receiving circuit for receiving the light projected by the light projecting circuit and reflected by the object, current-to-voltage conversion circuitry for converting a current output by the light receiving circuit into a corresponding voltage, amplifier circuitry for amplifying the output signals of the current-to-voltage conversion circuits, an integration circuit for integrating the output signal of the amplifier circuit, a level judgement circuit for judging the level of the output signal of the integration circuit by comparing it with a reference voltage, and an arithmetic circuit for switching the reference voltage depending on whether the light-projecting circuit is projecting light and for calculating the distance of the object based on the output of the level judgement circuit.