| 摘要 |
PURPOSE:To obtain a far visual field image with the stable quantity of light and to improve measurement accuracy by specifying the angle of light reception of the light incidence window of a light receiving waveguide, etc. CONSTITUTION:An optical fiber 6 which forms the light receiving waveguide is provided to a range of + or -90 deg. about the light emission point 2 of the laser light, etc., of a light emitting element 1 and a light receiver provided to the optical fiber 6 receives the far visual image of the light emission point 2 through the optical fiber. The light reception section of this optical fiber 6 is longitudinally long and the angle of light reception to the light output of the element 1 is set to >=3.5 deg. to stabilize the quantity of light reception and obtain the smooth far visual field image. consequently, measurement reproducibility is good and the measurement accuracy is improved. |
