OPTICAL SYSTEM FOR FOCUSING DETECTION,申请号JP19890343526-传众专利搜索

OPTICAL SYSTEM FOR FOCUSING DETECTION

申请公布号：JPH03200207(A)

申请号：JP19890343526

申请日期：1989.12.28

申请公布日期：1991.09.02

申请人：

OLYMPUS OPTICAL CO LTD

发明人：INAHATA TATSUO

分类号：G03B13/36;G02B7/30;G02B7/34

主分类号：G03B13/36

摘要：PURPOSE:To obviate the generation of erroneous distance measurement even if stray light infilters a prism by forming the non-effective optical path region of at least one prism surface which allows the transmission of the luminous flux passing the inside of the prism member and forming an object image or reflects the luminous flux as either of a light diffusing surface or surface coated with a light absorptive material. CONSTITUTION:The part A-B where the luminous flux from the subject does not pass in either of the case in which a joining material 11 is packed between an exit surface 10 and a photodetecting surface 7a or the case in which an air spacing is formed between the exit surface 10 and the photodetecting surface 7a is formed as the light diffusing surface 12 or the surface 13 coated with the light absorptive material. The stray light c is, therefore, shut off by this surface 12 or 13 and does not arrive at the photodetecting surface 7a. Thus, the arrival of the stray light at the photodetecting surface 7a of a photoelectric converting element is obviated and, therefore, the erroneous distance measurement is prevented.