LIGHT PROJECTING WINDOW OF AUTOMATIC FOCUSING CAMERA

摘要

PROBLEM TO BE SOLVED: To provide the transparent window of the light projecting part of an automatic focusing camera with which the light for distance measurement emitted from the light projecting part toward a subject is emitted outside the camera without hindering its convergent property. SOLUTION: The AF light projecting part including an IR light emitting diode 62 and a light projecting lens 68 is arranged on the inner side of the cover 11 of a camera 10. The front surface part of the light projecting lens 68 is provided with the AF light projecting part 18 formed of transparent plastic, etc. The window surface of the AF light projecting part 18 is formed to a curvilinear surface shape and the thickness of this curvilinear surface part thereof is so formed that the lengths (a), (b), (c) in the sectional part when the AF light projecting part 18 is cut with an arbitrary straight line parallel with the optical axis L of an IR beam are approximately constant (a≈b≈c). As a result, the optical path length at which the light parallel with the optical axis progresses in the medium of the AF light projecting part 18 attains an approximately equal distance regardless of the passing position of the window surface and the convergent property of the light converged by the light projecting lens 68 is maintained even if this light passes the AF light projecting part 18.