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:
Jul. 03, 2007
Filed:
Apr. 19, 2005
Nobuo Nabeshima, Kanagawa, JP;
Kayoko Taniguchi, Kanagawa, JP;
Eiko Kanbara, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
The present invention provides a displacement detection apparatus uses short scales and can provide a long measurable range comparable to a single long scale with a short bed length. The displacement detection apparatus includes a scale, a first head and a second head adapted to detect periodic analog signals of a plurality of different types, a first processing section and a second processing section that detects the first differential value and the second differential value between the immediately preceding positional data and the current positional data obtained by sampling the periodic analog signals of a plurality of different types, a switching section that selectively switches from the first differential value to the second differential value or vice versa, a scale position detection section that detects the scale getting to a predetermined position relative to the first head or a predetermined position relative to the second head, a switching control section that causes the switching section to switch from either of the differential values to the other in response to the detection of the scale getting to the predetermined position, and an addition section that adds the first differential value or the second differential value selectively switched by the switching control section and outputting it as positional information.