| 摘要 |
PURPOSE: A magnetic tape cassette is provided to surely prevent misdetection of a tape end of a magnetic tape. CONSTITUTION: A magnetic tape cassette is composed of transparent or semitransparent upper half and lower half(1a) portions. A light-shielding unit installed around a hole(7) for an optical path is composed of a light-shielding plate(2a) having a hole(11) for controlling quantity of light, a rib(8), and a holding unit(9) for inserting the light-shielding plate. Plural triangular shaped prisms(8a) are formed on at least one side of the rib continuously. Therefore, the light coming from the end surface of the rib and entering a light receiving element side is efficiently controlled and the light passing the inside the transparent or semitransparent upper half and lower half portions is sufficiently controlled. Therefore, detection of the tape end is surely performed.
|
