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:
Apr. 22, 2008
Filed:
Dec. 28, 2005
Nobuyuki Nishita, Kanagawa, JP;
Naoki Shoji, Kanagawa, JP;
Takashi Nagao, Kanagawa, JP;
Sokkia Co., Ltd., Kanagawa, JP;
Abstract
An auto focusing mechanism is provided in a surveying instrument, such as an electronic level, that is capable of automatically focusing a telescope on a sighted staff. As a focusing lens () is moved by a motor () along the optical axis of a telescope (), the image of a staff () sighted by the telescope () is converted into an electrical signal by a line sensor (). The output signal of the line sensor () is converted into a digital signal by an A/D converter () and stored in a RAM (). Based on the data stored in the RAM (), a microcomputer () monitors frequencies of the component signals, or wavelets, contained in the output signal of the line sensor () stored in the RAM (). When a particular frequency of the output signal associated with the position of the focusing lens () is detected a determination is made that the focusing lens () is located at a focusing position, and the distance from the telescope () to the staff () is calculated.