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:
Mar. 27, 1990
Filed:
Aug. 07, 1987
Souji Ichikawa, Sagamihara, JP;
Mitutoyo Mfg. Co., Ltd., Tokyo, JP;
Abstract
An optical type displacement detecting device including a main scale and an index scale, wherein a pitch of a first optical grating formed on the main scale is set at P and a pitch of a second optical grating formed on the index scale is set at P/n, thereby producing divided detection signal having pitch P/n. Furthermore, the pitch of the second optical grating is set at (u+v) P/u or (u+v) P/(2u) (u is a gap between a diffusive light source and the first optical grating and v is a gap between the first and second optical gratings), so that a collimator lens can be dispensed with. Further, higher harmonic components of the first optical grating are utilized, whereby the pitch of the second optical grating is set at substantially (u+v) Q/u or (u+v) Q/(2u) (Q=P/m, and m is a whole number of 2 or more), thereby preventing the pitch of the second optical grating from being divided into small ones.