JPS6180628A - Objective lens driver - Google Patents

Abstract

PURPOSE:To decrease the number of components, to simplify the shape of each component and to improve the reliability by providing the 1st coil for focus drive and the 2nd coil for tracking drive to a drive part including the support with respect to the objective lens driver used in an optical disc player. CONSTITUTION:An objective lens barrel 2 is provided with a permanent magnet 3 driven in the focusing direction (x) and a magnetic circuit 4 driven in the tracking direction (y). A base 5 is provided with a slide shaft 6, a focusing coil 7, and a tracking coil 8 together with a tracking coil fixed frame 9 and the objective lens 1 is driven in the focusing direction and tracking direction by flowing a current to a terminal 11. Since no coil member is fitted to a section to be driven, it is not required to wire a coil winding end so as to improve the reliability and to simplify the shape.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an objective lens driving device for reading information optically recorded on a recording medium.

[Background of the invention]

As an objective lens drive device used in an optical disc player, for example, Japanese Patent Application Laid-Open No. 57-21! 3456
As shown in the publication, the objective lens holding cylinder is slid in the thrust direction to perform the focusing operation, and
It is known to perform a tracking operation by rotating the objective lens around the axis of the holding cylinder rather than attaching the objective lens to the holding cylinder eccentrically from the sliding axis. Such an objective lens drive device includes a first cylindrical focus drive coil wound around the outer periphery of the objective lens holding tube, and a rectangular second tracking drive coil attached to the first coil for focus drive. It is equipped with a coil. Also, the first
The second coil is driven in the radial and thrust directions within a magnetic circuit in which a yoke provided inside the objective lens holding cylinder has another notch opposite to the outside notch. It is configured to

By the way, in the objective lens driving device described above, a plurality of rectangular second tracking coils are molded to match the arc of the first coil, and these molded coils are connected to form a circular magnetic field. It must be precisely attached to the objective lens holder so that it can operate without coming into contact with the gap. For this reason, it is very difficult to assemble the coil and manufacture the objective lens holding cylinder, which makes mass production difficult, and the complicated shape of the yoke makes the cost relatively high.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to correct the above-mentioned drawbacks and to provide an objective lens drive device that is highly productive and reliable.

[Summary of the invention]

The present invention provides a reduction in the number of parts and a reduction in the number of parts by providing the first coil and the second coil in the driving part including the spindle, and providing the permanent magnet arm and the magnetic circuit in the driven part. It is possible to simplify the shape and improve reliability.

[Embodiments of the invention]

FIG. 1 shows a side sectional view of an objective lens driving device according to the present invention, and FIG. 2 shows a partial sectional view from a plane.

The objective lens 1 is fixed to an objective lens holding tube 2, and the objective lens holding tube 2 includes a tubular permanent magnet 3 for driving in the focusing direction (tilt) and a magnetic circuit for driving in the tracking direction (tilt). 4 is provided.

Further, a sliding shaft 6 for sliding and rotating the objective lens is attached to the base 5.

Furthermore, a focusing coil 7 for driving in the focusing direction is wound around the base 5, and a tracking coil 8 for driving in the tracking direction is provided together with a tracking coil fixing frame 9.

The winding ends of each of the coils are connected to a substrate 1G on which a pattern is drawn, and a plurality of terminals 11 for supplying current are connected to the substrate 10 by solder or the like, so that current cannot be supplied to the terminals 11. Thick lens 1
can be driven in the focusing direction and tracking direction.

The objective lens drive device as described above, which has a structure in which the coil member is not attached to the driven part, has improved reliability because it is no longer necessary to route the winding end of the coil from the driven part to the driving part as in the conventional case. It is possible to improve the performance and also to facilitate the assembly. In addition, for the objective lens holding frame 2, instead of a guide section for coil winding, it is only necessary to provide grooves for attaching the permanent magnet 3 and the magnetic circuit 4, so the shape of the objective lens holding frame 2 can be greatly reduced. Can be simplified.

Furthermore, the complicatedly shaped yoke used in the past becomes unnecessary.

In addition, the magnetic circuit 4 is connected to the objective lens 1 with the sliding shaft 6 as the center.
If the mass of the magnetic circuit 4 is set at a position facing the magnetic circuit 4 such that the mass balance in the tracking direction is maintained, sliding will not occur even if the entire objective lens drive device is moved at high speed in the tracking direction. No rotation about the moving shaft 6 occurs. Therefore, there is no need to separately attach a balance weight for balancing, and the number of parts can be reduced and performance can be improved.

〔Effect of the invention〕

According to the present invention, it is no longer necessary to route the winding ends of the casing coil and tracking coil from the driven part to the driving part. The phenomenon of disconnection can be avoided, and reliability is greatly improved. Furthermore, since the assembly process of routing the coil winding ends can be omitted, productivity can also be improved.

Furthermore, the shape of the objective lens holding frame can be simplified and the tracking coil can be easily assembled, thereby reducing production costs and parts costs.

Furthermore, the magnetic circuit for driving in the tracking direction can also be used as a balance weight, and the number of parts can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of an objective lens driving device according to an embodiment of the present invention, and FIG. 2 is a partial sectional view taken from the plane of FIG. 1. DESCRIPTION OF SYMBOLS 1... Objective lens, 2... Objective lens holding frame, 3... Permanent magnet, 4... Magnetic circuit, 6... Sliding axis, 7... Focusing coil, 8... Tracking coil. 1st sip 2nd drink

Claims (1)

[Claims] In an objective lens drive device having an objective lens holding tube configured to be rotatable around a support shaft and slidable in an axial direction of the support shaft, the objective lens holding tube is provided with a spaced apart from the support shaft. an objective lens provided, a tubular permanent magnet for focus driving provided around the circumference of the objective lens holding cylinder, and a position facing the objective lens with the center of the spindle of the objective lens holding cylinder. a driven part provided with a magnetic circuit for tracking drive; a first coil for focus drive provided on the periphery of the base to which the spindle is fixed; and a first coil for focus drive provided in the magnetic gap of the magnetic circuit. 1. An objective lens driving device comprising: a driving section having a second coil for tracking driving provided at an intersecting position.