DISTANCE MEASURING OPTICAL SYSTEM OF CAMERA

摘要

PURPOSE:To obtain a distance measuring optical system of short size by covering a light emitting element with a light transmitting protective member made of resin or the like and regulating the shape of the covered member so as to produce a concave lens effect in the direction of the optical axis of a condenser. CONSTITUTION:The light emitting surface of a light emitting element 21 is covered with a transparent protective material 22 forming a concave lens. The distance D3 between a condenser 23 and the element 21 is made shorter as compared to a case where the cover is a convex lens or a parallel plate. The distance Nf from the rear side principal point H3' of the lens system to the element is, however, equal to that in a case using a convex lens or the like.