| 摘要 |
<p>PURPOSE:To obtain a tape starting and finishing ends detecting device capable of inexpensively and surely guding light beams from a light emitting part to a single light receiving part by inclining one pair of incident surfaces opposite to the light emitting part of a light transmission body at a prescribed angle. CONSTITUTION:The light beams 43 and 44 from one pair of light emitting elements are refracted by the incident surfaces 58 and 59 inclined by prescribed angle theta deg. of the light transmission body 55, and are made incident upon total reflection surfaces 60 and 61 at an angle <=45 deg. and are then reflected. Then, the totally reflected light beams 43 and 44 are converged in an approximately central part of a light-emitting surface 62, from which the beams are emitted to surely reach the single light receiving element 33. By this constitution, not only the device is inexpensive, but also the device is not required to consider how to cope with malfunction due to diffused external light because of the single light receiving element 33 provided to be positioned in the central inside part of a tape cassette. Moreover, the light emitted from one pair of light emitting elements can surely reach a light receiving element 33 by the light transmission body 55, thus enhancing transmission efficiency and suppressing malfunction to the utmost.</p> |
