| 摘要 |
PURPOSE:To reduce the load and danger to a patient and to miniaturize the title apparatus as a whole by reducing the output of a laser beam source, by arranging an optical element so that the optical axis of the laser scattering beam divided by the optical element to go toward a photoelectric converter element is positioned within the plane containing the optical axes of both of laser beam emitting and receiving parts. CONSTITUTION:The beam scattered at a measuring point P is split by a half mirror 21 and a part of the split beams is turned toward an examinee 33 to observe the same and simultaneously incident to a photoelectric converter elements 27 through a lens 22, a shutter 26' and a mask 26. Since the optical axis L1 of a beam emitting part and the optical axis L2 of a beam receiving part are arranged at almost 90 deg., the photoelectric converter element 27 receives lateral scattering beam in a 90 deg.-direction. In this case, the half mirror 21 is arranged so that the scattering beam is incident to the half mirror as an S- polarized beam, that is, so that the optical axis L4 of the laser scattering beam reaching the photoelectric converter element 27 is positioned within the plane containing the optical axes L1, L2 and, therefore, the scattering beam can be guided to the photoelectric converter element 27 efficiently. |
