JPS6364638A - Objective lens supporting device for optical recording and reproducing device - Google Patents

Abstract

PURPOSE:To suppress the resonance of an objective lens and to improve its controllability by providing a nonmagnetic conductive plate in a movable part that supports an objective lens movably parallel to the direction of moving of the movable part, and passing a magnetic flux in the direction of its thickness. CONSTITUTION:The magnetic conductive plate 3 and coils 7, 8 are supported in a gap between a magnet 6 and an inside yoke 9 while avoiding contact with a magnetic circuit. When current is applied to coils 7, 8, an objective lens 10 is driven by a tracking leaf spring 1 and the focusing leaf spring of the conductive plate 3 in the direction, and simultaneously eddy current is generated in the conductive plate 3 to restrict the movement of the lens 10. The binding force is proportionate to the relative speed of the conductive plate 3 and the magnet 6, and suppresses high order resonance harmful to the control of the lens 10, and facilitates and stabilizes the control of the lens.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an objective lens support device for a round type recording/reproducing device.

[Summary of the invention]

The present invention provides an objective lens support device for an optical recording/reproducing device, in which a non-magnetic conductive plate fixed to a movable member supporting the objective lens moves through the magnetic flux of a magnetic circuit configured in a fixed part. A damping force is applied to the member to reduce the resonance of the objective lens that is harmful to recording and reproduction.

[Conventional technology]

As described in Japanese Unexamined Patent Publication No. 60-29945 and shown in FIG. 2, an objective lens support device has been known in which a viscous material or a cushioning material is brought into close contact with the surface of a leaf spring or between a number of leaf springs.

[Problem that the invention seeks to solve]

However, conventional objective lens support devices are made of viscous material.

Another problem is that the damping force does not grow well with respect to the deformation of the cushioning material, and the sign of the damping force changes greatly due to temperature changes. The present invention is intended to solve these problems, and its purpose is to stabilize the damping force of the objective lens support device against speed and temperature changes, and to suppress the resonance of the objective lens. This is intended to improve the controllability of the objective lens.

[Means for solving problems]

The objective lens support device of the optical recording and reproducing device of the present invention includes:
The movable part has a non-magnetic conductor plate parallel to the movable direction, and the fixed part has a magnetic circuit that can pass magnetic flux in the thickness direction of the non-magnetic conductor plate.

[Effect]

By moving the movable part of the objective lens support device of the optical recording/reproducing apparatus configured as described above using electromagnetic force or the like, an eddy current is generated in the non-magnetic conductor plate. It receives a damping force from the magnetic field of the fixed part depending on the speed of the motor. As a result, higher-order resonance is suppressed and controllability is improved.

〔Example〕

A nine-piece embodiment will be described below with reference to the drawings. In FIG. 1, magnet 6 and outer yoke 5. Rear side joint - iron 4.
The inner yoke 9 is fixed to a chassis or the like, and these constitute a magnetic circuit as a fixed part. As shown in FIG. 4, in the gap between the magnet 6 and the inner yoke 9, a non-magnetic conductor plate 3 and a tracking coil 7 and a focusing coil 8 fixed to the non-magnetic conductor plate 3 are placed in a non-contact manner with the magnetic circuit. It is supported as follows. As shown in FIG. 5, the nonmagnetic conductor plate 3 is made by cutting a nonmagnetic conductor into a 7-shape and then forming it into a rectangular pipe shape, which serves both as a nonmagnetic conductor and as a focusing leaf spring. The non-magnetic conductor plate 30 is fixed to the tracking plate spring 1 via the connecting member 2, and further attached to the tracking plate spring 1.
The other end is fixed to the chassis etc. similarly to the magnetic circuit. A lens holder 11 is fixed to the tip of the non-magnetic conductor plate 3, and an objective lens 10 is further fixed inside the lens holder 11.

In the above configuration, each coil in the magnetic circuit receives a force by passing a current for driving the objective lens 10 through the tracking coil 7 and the focusing coil 8. The magnetic conductor plate S is driven only in the direction perpendicular to the surface of each spring by the seven occasing leaf spring parts. At this time, the non-magnetic conductor plate 3
An eddy current is generated in a portion of the magnetic circuit, which acts as a resistance force against the movement of the objective lens 10. The resistance force due to this eddy current is proportional to the relative speed between the nonmagnetic conductor plate 3 and the magnet 6,
Therefore, high-order resonance harmful to control of the objective lens is suppressed, and controllability is improved. In this embodiment, the non-magnetic conductive plate 3 is integrated with the focusing leaf spring in order to reduce manufacturing costs and weight, but these can also be made independent, and the material can be changed depending on the situation.゛It is possible to change the plate thickness, etc., making it possible to design to optimize characteristics.

The present invention can be applied to optical recording and reproducing devices such as compact discs, ODROMs, video discs, and data file discs, and can greatly improve product stability.

〔Effect of the invention〕

As explained above, the present invention provides good resistance to linearity with respect to speed and stability with respect to temperature changes by means of eddy currents generated in the non-magnetic conductive plate of the movable part in a device that movably supports an objective lens. This has the effect of making the control of one objective lens easier and more stable.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an objective lens support device according to the present invention;
FIG. 2 is a sectional view of a conventional objective lens support device, FIG. 5 is a sectional view of a leaf spring used in the conventional objective lens support device, and FIG. 4 is a partial sectional view of a magnetic circuit according to the present invention.
FIG. 5 is a perspective view showing an embodiment of the nonmagnetic conductor plate shape of the present invention. 1... Tracking leaf spring 2... Connection member 3... Non-magnetic conductor plate 4... Rear yoke 5... ...Outer yoke 6 ... Magnet 7 ... Tracking coil 8 ...
...Focusing coil 9...Inner yoke 104, ...Objective lens 11: ...Lens holder 12...Mirror frame 13... ... Control spring 14 ... Viscous material layer 15 ... Leaf spring 16 ... Silicone resin layer or higher

Claims (1)

[Claims] (1) In a device that movably supports an objective lens for recording, reproducing, and erasing information on a recording medium using optical means, the movable part has a nonmagnetic conductive plate parallel to the movable direction, An objective lens support device for an optical recording/reproducing device, characterized in that a magnetic circuit capable of passing a magnetic flux in the thickness direction of the non-magnetic conductive plate is configured in a fixed part.