West Electric Co., Ltd.

Youichi Iwai

Hiroshi Iwata

Toshitsugu Kashihara

Nobuo Yamashita

A zoom lens apparatus comprising a moving construction for moving a zoom-ratio adjusting barrel composed of a variator-lens amount and a compensator-lens mount by the rotation along the direction of the optical axis within the fixed barrel; a stepping motor, which is coupled to the moving construction is composed of a rotor having a hollow portion as a light path including the optical axis and a stator to be combined with the rotor, and reversibly rotates in accordance with the pulse signal to be applied; and a circuit means for controlling the operation of the stepping motor with providing advantages and that the reduction gear and clutch mechanism are not required, the outer shape is kept cylindrical, but is not required bigger in size and the price can be made lower.

Zoom lens apparatus

A lens drive mechanism comprising a lens mount, a basic barrel having a compartment defined therein for accommodating the lens mount for movement in a direction parallel to the optical axis, a pin member, and a generally semicircular cross-sectioned cam member mounted so as to cover the basic barrel for rotation about the optical axis and having a cam groove defined therein with the free end of the pin member engaged in the cam groove.

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Moriguchi, Japan

Youichi Iwai