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:
Feb. 17, 1987
Filed:
Mar. 03, 1983
Kuniichi Ozawa, Hirakata, JP;
Yasuhiro Goto, Kadoma, JP;
Hiromi Nakase, Nara, JP;
Shinya Yukino, Katano, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
An optical rotation detecting apparatus for a bushless dc motor detects rotation information of the shaft by the slits arranged at equal pitches along the circumference of a rotary disk and a photoelectric conversion element arranged circumferentially at a pitch which is an integral multiple of the slit pitch and including a first set of photoelectric conversion element pieces arranged alternately with the former thereby generating a first rotation information signal having a frequency proportional to the rotational speed of the shaft and a second rotation information signal having a 90-degree phase difference with the first rotation information signal. The phases of the first and second rotation information signals are compared to detect the direction of rotation of the shaft. The accuracy of rotation information can be further improved by increasing the number of photoelectric conversion element pieces per slit pitch. The photoelectric conversion element includes an amorphous silicon photoelectric conversion element.