| 主权项 |
1. A hollow-cone and point-focusing conoscopic illumination optical device for an optical microscope, comprising:
illumination means comprising a point light source, said illumination means being able to generate a collimated incident light beam (10), an optical objective (6) having an optical axis (8, 8′) and an image focal plane (12), the optical objective (6) being arranged so as to receive a cylindrical incident light beam (50) and to form an image of the source at one point (18) in the image focal point (12), characterized in that the illumination optical device comprises: an optical system comprising a first conical lens (1) and a second conical lens (5), said optical beam being arranged on the optical path of the incident light beam between the illumination means and the optical objective (6), the first conical lens (1) being arranged so as to receive said collimated incident light beam (10) and to form a hollow-cone light beam (20) having, in a plane transverse to the beam axis, a light distribution comprising a dark central part and a bright ring part, the second conical lens (5) being arranged so as to receive said first hollow-cone light beam (20, 40) from the first conical lens (1) and to form a black-background cylindrical light beam (50) having, in a plane transverse to the beam axis, a light distribution comprising a dark central part and a bright ring part, and in that the optical objective (6) is arranged so as to receive said black-background cylindrical light beam (50) from the second conical lens (5), to form a hollow-cone light beam (60) and to focus said hollow-cone light beam (60) at one point (18) of micrometric size in the image focal plane (12). |
