| 摘要 |
<p>A plurality of aperture blades (24) are each provided with an opening (30) having a V-shaped edge (32), such that when the blades (24) are superimposed they cooperate to define a six-sided aperture. The blades (24) are each mounted for rectilinear movement by a pair of guide pins (46). Cam pins (44) supported on a driver (31) rotated by a stepper motor (40) engage cam slots (28) in the blades (24) and position them rectilinearly to change the aperture size.</p> |
