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. 13, 2012
Filed:
Jun. 09, 2009
Yutaka Miki, Kawasaki, JP;
Yutaka Miki, Kawasaki, JP;
Mitutoyo Corporation, Kanagawa, JP;
Abstract
A first light detector and a second light detector, in each of which a plurality of light-receiving elements are arranged in an adjoining manner, are respectively provided anterior to an image-forming point of first reflected light and posterior to an image-forming point of second reflected light. A focal-point detecting circuit includes: maximum value selectors for selecting the maximum values from sums of light-receiving signals from adjoining light-receiving elements of the first light detector and the second light detector respectively; a total value operator for obtaining the total value of light-receiving signals from all the light-receiving elements of each of the first light detector and the second light detector; a light-detecting-signal operator for obtaining light-detecting signals by subtracting the maximum values from the total values; and an error-signal operational circuit for outputting a difference between the light-detecting signals to a servo circuit as a signal based on an amount of displacement between a focal point and a measuring face.