| 摘要 |
PURPOSE:To perform accurate focusing even in the case of a substance whose reflected light quantity is not constant like a living body sample by changing the profile of a beam spot by the use of the focusing knob driving means of an objective lens and controlling so that the detected value may be the maximum brightness. CONSTITUTION:A laser beam 12 is inducted from an image-formation lens 4 and projected from the objective lens 2 to be converged on the surface of the sample 3. The reflected object light passes through a microscope 1 again and is inputted in a TV camera 6 through the image-formation lens 4. Based on data from the TV camera 6, the beam spot 13 is displayed on a CRT display device 7. The beam spot 13 of the TV image is scanned by a scanning line and data on the spread of beam sigma<2> and the intensity of beam Ip is transmitted to a CPU 10. Then, a step motor being the focusing knob driving means 11 is controlled with a control signal from the CPU 10 to adjust a focusing knob. It is a focusing state that Ip is maximum and sigma<2> is minimum. |
