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:
Jan. 13, 2004
Filed:
May. 10, 2001
Other;
Abstract
A surveying instrument includes a sighting telescope having an objective lens and an eyepiece; a Porro-prism erecting system; a semitransparent surface formed on a reflection surface of the Porro-prism erecting system; a beam splitting prism adhered to the semitransparent surface; and a focus detecting device which detects a focus state from a correlation between a pair of images respectively formed by two light bundles which are respectively passed through two different pupil areas of the objective lens and passed through two separate areas on the semitransparent surface. An area of a surface of the beam splitting prism which is adhered to the semitransparent surface is smaller than an effective area of the reflection surface of the Porro-prism erecting system. The semitransparent surface and the beam splitting prism are positioned so that the two light bundles are incident on the semitransparent surface at the same incident angle.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile