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:
May. 28, 1991
Filed:
Sep. 10, 1990
Mitsutoshi Yagoto, Osaka, JP;
Masayuki Mino, Osaka, JP;
Minolta Camera Kabushiki Kaisha, Osaka, JP;
Abstract
An automatic focusing apparatus having an objective lens for forming a beam from a semiconductor laser as a spot image on an image subjecting face, a driving unit for driving the objective lens in a direction parallel to an optical axis thereof, a beam splitter disposed between the semiconductor laser and the objective lens, a pair of grids for generating a moire image displaced in a travelling path of a beam returning from the image subjecting face and reflected by an inclined prism face of the beam splitter, a photo detector for detecting the moire image generated by the grids and an control unit for evaluating a focusing error based on a variation in the moire image pattern and for controlling the driving unit so as to correct the focusing error. The first grid and the second grid are interspaced in parallel to each other along a beam axis and angularly displaced from each other about the beam axis.