Focal plane shutter having synchronous contact member

摘要

A focal plane shutter for a camera has a synchronous contact member that produces less chattering than conventional synchronous contact members. One end of an opening electromagnet and one end of a closing electromagnet are separately connected to the higher-potential side of a power supply for a CPU in the camera, and the other ends of the electromagnets are grounded. An output circuit has an inverter circuit made up of a transistor and two resistors. A driver voltage for energizing the closing electromagnet is applied to the base of the transistor via a first resistor. The collector of the transistor is connected to the higher-potential side of the power supply via a second resistor. The emitter of the transistor is connected to the lower-potential side of the power supply. First and second voltage signals are produced from an output terminal on the side of the collector. One end of the synchronous contact member is connected to the lower-potential side of the power supply and the other end thereof is connected to the base of the transistor.