| 摘要 |
PURPOSE:To eliminate an influence of a reflection by the surface of a lens, to raise the degree of freedom of a convergence of a projected light beam, and to detect a distance with a high accuracy by projecting a beam onto an object through a position which is not converged by an observation lens, and projecting it onto a light position detecting element through a reflecting body. CONSTITUTION:An optical beam B of a light source S is irradiated to an object O through a hole H of the center part of an observation lens L, and an image of its mark T is reflected by a cylindrical mirror M, and projected onto a light position detecting element P after passing through the observation lens L. A distance between the object O and the observation lens L can be measured by detecting a position of the mark T on the element P, a reflection of the beam B by the surface of the lens L is eliminated, a converging position of the projected optical beam B can be selected independently from an observation system, a size of an optical image can be set to a desirable state, and a distance can be detected stably and also with a high accuracy by a small-sized device. |
