Patent ID: 8115982
Filing Date: 2012-02-14
Classification: G03B,H04N

Abstract:
1. An iris diaphragm device comprising: two blade members supported respectively on two parallel rotary shafts; a lamp optical path defined between the two blade members; a motor driving directly one of the two rotary shafts; and a means of transmitting power from the one rotary shaft to the other rotary shaft, wherein the motor and the means are disposed off the lamp optical path, and the two blade members revolve respectively with respect to the two rotary shafts whereby a blocked area of the lamp optical path is adjusted, and wherein a magnetic sensor which includes a plate-like magnetic sensing portion and a plate-like magnet and which detects a rotation angle of the rotary shafts is disposed on an axis line of one of the two rotary shafts and also off the lamp optical path such that facing surfaces of both the magnetic detecting portion and the magnet are oriented orthogonal to the rotary shafts.