| 摘要 |
PURPOSE:To obtain a lightweight, inexpensive high-precision photographic lens which consists of a small number of elements and is easily assembled by composing a lens barrel of two split lens barrels which abutting on each other in a plane containing the optical axis of the lens. CONSTITUTION:Lenses 11, 12, and 13 are pressed in and inserted into grooves 22, 23, and 24 along shoulders 16, 17, and 18 as key drivers of one split lens barrel 10 while inner collars 19, 20, and 21 are deformed elastically. The lenses 11-13 are inserted at accurate lens intervals by contacting the shoulders 16-18 and also clamped with the reaction force resulting from the semicircular elastic deformation on the split lens barrel 10 which is almost in such a U shape that the radius R1 of an opening part is smaller than the depth-directional radius R2. Then, the other split lens barrel 10 is set in abutting relation and tenons 14 of the both are fitted in mortises. The inner peripheral length of grooves 22-24 is a half as large as the outer peripheral length of the lenses 11-13, so the lenses 11-13 are mounted in the grooves 22-24 without any gap. Then, abutting surfaces of the split lens barrels 10 are fixed by ultrasonic melt-sticking or with an adhesive, etc. |
