| 摘要 |
PURPOSE:To exactly start a lens motor of an auto-focusing camera, by making a large current flow so that the motor overcomes a load resistance and is started when it starts. CONSTITUTION:When an image forms an image on the photodetecting surface of a self-scanning type photoelectric element 3 through a lens 2, the photoelectric element 3 forms a photodetecting signal, and applies it to an automatic focus controlling circuit 5. The automatic focus controlling circuit 5 forms a prepin signal (a), a pospin signal (c) and a focusing deviation signal (b) in accordance with a signal from the photoelectric element 3, and applies them to a motor driving circuit 6. The motor driving circuit 6 decides the polarity of a current supplied to a motor 8, and magnitude of said current by the signals (a), (c), and the signal (b), respectively. Also, a start signal (e) which a start pulse generating circuit 7 has formed in accordance with an AF operation command from a camera circuit is applied to the motor driving circuit 6, and when this start signal has been applied, a prescribed large current is made to flow to the motor 8, and the lens motor is started exactly. |
