| 摘要 |
PROBLEM TO BE SOLVED: To obtain a distance-measuring apparatus in which the damage such as the crack or the like of a bonding face and the degradation of optical characteristic due to temperature change are suppressed by making one of achromatic image-formation lenses possible to be relatively contact-displaced to the other. SOLUTION: The ends on one side of plano-concave lenses 20R, 20L are fixed with a lens tightening screw 26 so as to be used as fixed ends, and ends on the other side are pressed from above by a leaf-spring lens holder 29 so as to be used as expansion and contraction free ends having the degree of a small freedom. Thereby, since the lenses 20R, 20L can be expanded freely at a high temperature, the generation of a thermal stress can be suppressed, and the degradation of various optical characteristics due to the influence of heat can be reduced. In addition, ends on one side of plan-convex lenses 22R, 22L on the upper side are not fixed with the screw 26 so as to be used as free ends. Since the ends on the other side are pressed from above by the lens holder 29, they are used as expansion and contraction free ends having the degree of freedom to a certain extent. As a result, the lenses 22R, 22L can be contact- displaced onto the lenses 20R, 20L relatively. |
