| 摘要 |
PURPOSE:To arrange a harmful light cutting diaphragm member effectively between a moving cylinder for moving a zooming lens and a fixed cylinder by forming projected spiral cams on the inner and outer peripheries of a cylindrical member. CONSTITUTION:The fixed cylinder 1 has a coupling member (bayonet ring) 1a. A straight groove 2a and a cam groove 2b are formed on the 2nd fixed cylinder 2 coupled with the fixed cylinder 1 by a screw 6 through a spacer 4. The moving cylinder 8 engaged with the inside of the fixed cylinder 2 is coupled with an operating member 10 applied to the outside of the fixed cylinder 1 through a coupling member. A pin 8c is planted on the outer periphery of the moving cylinder 8 ad engaged with the straight groove 2a of the fixed cylinder 2 to regulate the rotation of the moving cylinder 8. The diaphragm member 20 varies a distance from the 3rd lens group L3 in accordance with the leads of the cams 20a, 20b over a range from a TELE terminal to a WIDE terminal based upon the zooming operation and cut off harmful light projected from the 3rd lens group L3 by a flange part 20c.
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