Patent ID: 6490416
Filing Date: 2002-12-03
Classification: G03B

Abstract:
A focal plane shutter having a shutter base plate provided with a shutter opening, an opening sector for opening the shutter opening, and a closing sector for closing the shutter opening, the focal plane shutter comprising:an electromagnet operative when energized by a driver voltage to prevent the closing sector from starting to close the shutter opening; a normally closed switch linked to the opening sector and being opened when the shutter opening is opened, the switch having a first end connected to a low potential side of a power supply and a second end; a resistor connected between the electromagnet and the second end of the switch for providing the driver voltage to the switch; and an output circuit for producing an opening signal when a junction point between the resistor and the second end of the switch is at a low potential and for producing a given signal different from the opening signal when the junction point is at a high potential.