| 摘要 |
PURPOSE:To eliminate the instability of positional precision due to the variance of temperature by providing boss holes in both end positions in the lens arrangement direction of a transparent plastic plate and inserting bosses loosely through boss holes and joining the upper end part of one of these bosses at least to the surface of the plastic plate with an adhesive. CONSTITUTION:Boss holes (h) and (h) are provided in both end positions in the arrangement direction of lenses 10 and 12 on a plate piece 9. Bosses B and B are formed on a base body 13 in accordance with these boss holes. In case of assembling, holes 14c and 14d in both ends of a stop plate 14 are pierced by bosses B and B, and next, boss holes (h) and (h) of the plate piece 9 are pierced by bosses B and B. Bosses B are fitted loosely to boss holes (h), and tips of bosses B and B are at the same height as the surface (the face seen in the figure) of the plate piece 9 when the stop plate 14 and the plate piece 9 are put one over the other and are pierced by bosses B and B. In such a state, an adhesive is applied to tips of bosses B and B and the surface of the plate piece 9. After the adhesive is hardened, a rear cover 16 is attached to the base body 13, thus terminating assembling. |
