Patent Number: 6,253,457

Title: Laser beam direction correcting optical system for a surveying instrument

Abstract: A laser beam direction correcting optical system for a surveying instrument comprises a laser light source (1) for emitting a laser beam, an exit angle correcting system (17) for correcting an exit angle of the laser beam emerging therefrom in accordance with an inclination of an instrument main body so that the laser beam is oriented in a specific direction, and an incident angle correcting system provided between the laser light source (1) and the exit angle correcting system (17) to correct an incident angle of the laser beam incident upon the exit angle correcting system in accordance with the inclination of the instrument main body. The exit angle correcting system (17) comprises an objective lens (19), the objective lens (19) being constituted by a variable-focus lens in which a position of a principal plane thereof on an optical axis thereof is fixed and also which can vary a position at which an image of the laser beam is formed.

Inventors: Ohtomo; Fumio (Tokyo, JP), Ishinabe; Ikuo (Tokyo, JP), Kodaira; Jun-ichi (Tokyo, JP)

Assignee: Kabushiki Kaisha Topcon

International Classification: G01C 15/00 (20060101); G02B 27/64 (20060101); G01C 005/00 (); G01C 001/00 (); G02B 023/00 ()

Expiration Date: 07/03/2018