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Camera lens barrel having both pulse drive control and microstep drive control

  • US 5,519,465 A
  • Filed: 04/07/1994
  • Issued: 05/21/1996
  • Est. Priority Date: 11/09/1990
  • Status: Expired due to Term
First Claim
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1. In a camera lens barrel having a first grouped lens, a movable second grouped lens for variable magnification, a third grouped lens, and a fourth grouped lens, which are respectively arranged along an optical axis, and accommodating a drive system for said first to fourth lenses, the improvement comprising:

  • a stepping motor having a lead screw mounted on an outer surface of a rotary shaft;

    control means selectively carrying out in a low speed drive mode and in a high speed drive mode at least micro step drive control and pulse drive control of said stepping motor and providing position control of said second grouped lens according to a control quantity of said stepping motor;

    a frame for the second grouped lens which is directly engaged with said lead screw, said lead screw and frame directly converting rotation of said stepping motor into movement of said second grouped lens along said optical axis; and

    a mode switch for selecting said high-speed drive mode or said low-speed drive mode, wherein when the high-speed drive mode is selected, said control mean carries out pulse drive control of said stepping motor, while when the low speed drive mode is selected, said control means carries out the micro step drive control of said stepping motor.

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