Nhk Spring Co., Ltd.

Akio Shibusaka

Jun Tominaga

Hidemi Haga

A resilient support member,is provided between a lens holder,and a base member,to resiliently support the lens retainer,with respect to the base member,. A pair of auxiliary damping members,and,extend along the length of the resilient support member,, and a viscoelastic material piece,is provided between the two auxiliary damping members so as to connect them to each other. Various modes of connection can be achieved, and the freedom in the tuning of the damping effect is increased for reducing spurious resonant vibrations so that an adequate damping effect can be achieved. Because the part to which the viscoelastic material is to be applied is placed in a wide space remote from the lens retainer and the base member, the work of applying the viscoelastic material is simplified.

Actuator for objective lenses

The peak value of the higher resonant frequency vibration of a moveable part of an object lens actuator is reduced without requiring any additional mounting space, increasing the number of component parts or adding weight by appropriately adjusting the mounting arrangement for the mass balancer for placing the gravitational center of the moveable part at a desired position as well as the dimensions and shape of the mass balancer so that the mass balancer may have the same resonant frequency as the higher harmonic resonant frequency of the moveable part, and oscillate in the opposite phase. Therefore, the vibration of the moveable part can be favorably controlled, and the rotational speed of the disk and the head speed can be increased so that the access speed of the optical disk unit or the magneto-optical disk unit may be increased.

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Yokohama, Japan

Akio Shibusaka