Patent ID: 6253457
Filing Date: 2001-07-03
Classification: G01C,G02B,Y10S

Abstract:
A laser beam direction correcting optical system for a surveying instrument, comprising:a laser beam light source for emitting a laser beam;exit angle correcting means for correcting an exit angle of said laser beam emerging therefrom in accordance with an inclination of an instrument main body so that said laser beam is oriented in a specific direction; andincident angle correcting means provided between said laser light source and said exit angle correcting means, for correcting an incident angle of said laser beam incident upon said exit angle correcting means in accordance with said inclination of said instrument main body;wherein said exit angle correcting means comprises two groups of objective lenses and another objective lens, which is arranged between said incident angle correcting means and said two groups of objective lenses, and a position of a complex principal plane of said two groups of objective lenses on an optical axis thereof is fixed against to an image forming position of said another objective lens.