Patent ID: 8064133
Filing Date: 2011-11-22
Classification: G01J,G02B

Abstract:
1. A light receiving optical system for view angle switching control, comprising: an objective optical system for allowing incidence of light to be measured; a view angle defining aperture member having a view angle defining aperture for defining a view angle; a relay optical system for converging the light to be measured which has been converged on an image plane of the objective optical system on the view angle defining aperture for incidence through the view angle defining aperture, the relay optical system having a relay lens operable to be selectively switched between a first conjugate position and a second conjugate position; a first light flux limiting aperture member having a first light flux limiting aperture for limiting a light flux of the light to be measured located in proximity to the relay lens in the case where the relay lens is shifted to the first conjugate position; and a second light flux limiting aperture member having a second light flux limiting aperture for limiting a light flux of the light to be measured located in proximity to the relay lens in the case where the relay lens is shifted to the second conjugate position, wherein the relay optical system is operable to selectively form, on the image plane of the objective optical system, an enlarged image of the view angle defining aperture in the case where the relay lens is shifted to the first conjugate position, and a reduced image of the view angle defining aperture in the case where the relay lens is shifted to the second conjugate position to switch over the view angle, and the first light flux limiting aperture member and the second light flux limiting aperture member are operable to limit an incident light flux through the view angle defining aperture by the first light flux limiting aperture and the second light flux limiting aperture, respectively, in the case where the relay lens is selectively switched between the first conjugate position and the second conjugate position.