Patent ID: 7791795
Filing Date: 2010-09-07
Classification: G02B

Abstract:
1. A microscope provided with a focusing assist apparatus, comprising: a light source; a first lens group; a diameter-variable diaphragm which is disposed at a position which is conjugate with said light source while said first lens group is interposed therebetween; an optical path branching member which is illuminated with a luminous flux restricted by said diameter-variable diaphragm, said optical path branching member having a focusing indicator and forming two luminous fluxes, the luminous fluxes being inclined by predetermined angles from an optical axis; a second lens group; and an objective lens, wherein said diameter-variable diaphragm is disposed at a position which is conjugate with a pupil plane of said objective lens while said second lens group is interposed therebetween, said focusing indicator of said optical path branching member is disposed at a position which is conjugate with an observed surface by said second lens group and said objective lens, said optical path branching member is insertable into and is retractable from a microscope optical path, a diameter φ of said diameter-variable diaphragm is set at a predetermined value suitable to focusing assist when said optical path branching member is inserted into the microscope optical path, and the setting suitable to the focusing assist is given by satisfying simultaneously the following conditional expressions (1) and (2), where β