| 摘要 |
PURPOSE:To mold a prism having excellent optical characteristics by facilitating the production of a sliding core for molding the prism for detecting a tape terminal and improving the flatness of a prism forming surface. CONSTITUTION:A 1st reflection surface forming surface 45, front surface forming surface 44 and 2nd reflection surface forming surface 43 extending from the front surface to the rear surface of the body are machined and formed in a part on the flank of the plate planar body and thereafter, these forming surfaces are polished by machining to form a 1st planar member 2. One sheet of the 1st planar member and one sheet of a 2nd planar member 3 having a mere flat shape are superposed on each other, by which the sliding core 1 is constituted. |
