| 摘要 |
PROBLEM TO BE SOLVED: To reduce the cost of an iris encoder circuit and to improve temperature-compensating properties. SOLUTION: The temperature-compensating of an iris encoder is performed by using the output of a temperature sensor provided to correct the cam trajectory of a compensator lens group accompanying the expansion and contraction of a lens barrel caused by a change in temperature, in a rear focus zoom lens, so that a diode used in the conventional manner is eliminated and the cost is reduced. Further, in a temperature-compensating sensor for an RFZ cam trajectory, temperature changing properties are more linear than those of the diode and a temperature change rate can be freely changed only by changing a circuit resistance constant, so that more accurate temperature-compensating can be performed. COPYRIGHT: (C)2006,JPO&NCIPI
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