JPH0447899B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the pickup of an optically recorded disc, primarily a video disc player.

The pick-up functions of a player for optically recorded information, mainly optical video disks, include focusing, which focuses the read beam on the disk surface, and tracking, which causes the read beam to follow the information track. Furthermore, in some cases, the reading beam is moved in the track direction to adjust the timing of the reading signal. Conventionally, focusing was performed by moving the objective lens in the optical axis direction, and tracking was performed by moving a galvanometer mirror to tilt the reading beam incident on the objective lens.

However, in order to move the galvano mirror at a fairly high speed for tracking, a large amount of force is required, and the mechanism of the device becomes large-scale, which inevitably consumes a large amount of power. On the other hand, Japanese Patent Application Laid-Open No. 52-55424 discloses an apparatus for driving a lens in two-dimensional directions using a focusing coil and a tracking coil. FIG. 7 of the publication describes a configuration in which two types of coils are integrally fixed to a lens holder so that the coils and the lens can move together. However, this technique has the disadvantage that the device becomes large because it uses magnets for focusing and tracking separately and independently.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pickup device that is simple in structure, small in size, and lightweight.

The pick-up device of the present invention reads information from a recording medium on which information is recorded in the form of a track.
a first coil for driving the lens in a first direction perpendicular to the medium surface of the recording medium; and a second coil for driving the lens in a second direction parallel to the medium surface and across the information track. Both the first and second coils are substantially fixed to the lens holder so that the coils move together with the lens holder for holding the lens, and the base and the lens holder are In the pickup device, the lens is connected to the body by an elastic member and driven in both the first and second directions, wherein both the first coil and the second coil are connected to the medium surface. fixing to the base a magnetic field generating means that forms a vertical conducting wire arrangement surface (an apparent surface created by arranging a plurality of conducting wires in close proximity) and having a surface perpendicular to the medium surface;
The surface of the magnetic field generating means and the conductive wire arrangement surfaces of both the first and second coils are arranged so as to face each other with a gap therebetween, and the magnetic field generated in the first coil by energization of the coil is The lens is driven in the first direction and the second direction by using a force perpendicular to the medium surface and a force parallel to the medium surface generated in the second coil. It is something to do.

An embodiment of the present invention will be described in detail below based on the drawings. In the present invention, focusing and tracking adjustment can be performed by moving the lens in each direction, so the drive mechanism can be simplified and it is superior to conventional examples in terms of size and power consumption. ing. Note that since the lens only needs to handle light beams perpendicular to the optical axis, it can be of a simple configuration, and therefore lightweight and compact. Furthermore, if it is desired to compensate for a temporal shift in the readout signal due to uneven rotation of the disk, etc., the lens may be moved in a direction perpendicular to the paper plane of FIG.

Next, a mechanism for driving the lens in each direction is shown in FIGS. 1 and 2. FIG. 1 is a cross-sectional view of the lens drive mechanism along the optical axis. The lens 12 is attached to a cylindrical lens frame 13 with a flange, and the lens frame 13 is equipped with a spring 14 and a damper 1.
It is attached to the magnet 16 via 5. The spring 14 bends in the direction of the optical axis of the lens 12,
The lens 12 is also stretchable in the radial direction, so the lens 12 and frame 13 can move in the optical axis direction and the radial direction. Furthermore, a coil bobbin 17 is attached to the lens frame 13, and a coil having the structure shown in FIG. 2 is formed on this. FIG. 2a is a perspective view of the coil, and FIG. 2b is a view of the coil viewed from the optical axis direction. As shown in the figure, there are four coils 18 to 2 on the surface of the bobbin 17.
1 is provided. A normal coil 22 is wound on top of these coils.

A magnetic field is formed in the gap 23 by the magnet 16, so if a current is passed in the appropriate direction through the coils 18 and 20, the coil bobbin 17 will move in a direction perpendicular to the optical axis, and if current is passed through the coils 19 and 21, the coil bobbin 17 will move in a direction perpendicular to the optical axis. move in a direction perpendicular to this. Furthermore, when a current is applied to the coil 22, the bobbin 17 moves in the optical axis direction. Therefore, the lens 12 also moves in each direction as these move.
The lens 12 can be moved in each of the above-mentioned directions by the current flowing through each coil.

It should be noted that the present invention is not limited to the above-described embodiments, and can of course be used not only for video disc playback devices but also for example for disc playback devices on which music information is recorded.

As described above, the present invention includes forming conductor array planes perpendicular to the medium surface of the recording medium in both the focusing coil and the tracking coil, and fixing the magnetic field generating means having the plane perpendicular to the medium surface to the base. Since the surface of the magnetic field generating means and the conducting wire arrangement surfaces of both the first and second coils are arranged to face each other with a gap in between, the lens holder, the coil, and the magnetic field generating means can be easily made compact. By using a common magnetic field generating means for focusing and tracking, the pickup device of the present invention has the advantage that it can be made even more compact.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of a mechanism for moving the lens in each direction, and FIGS. 2A and 2B are a perspective view and a diagram of a coil for moving the lens in each direction as seen from the optical axis direction. 12...lens, 13...lens frame, 14...
Spring, 15... Damper, 16... Magnet,
17...Coil bobbin, 18-21...Coil,
22...Coil, 23...Gap.

Claims (1)

[Claims] 1. In order to read information on a recording medium on which information is recorded in a track shape, a first coil for driving a lens in a first direction perpendicular to the medium surface of the recording medium and the lens are attached to the medium surface. a second direction for driving in a second direction parallel to and across the information track;
The first coil moves together with the lens holder for holding the lens.
and a second coil are substantially fixed to the lens holder, a base and the lens holder are connected by an elastic member, and the lens is fixed to the first and second coils.
In a pickup device that is driven in both directions, both the first coil and the second coil form a conductor array surface perpendicular to the medium surface, and a surface perpendicular to the medium surface is formed. A magnetic field generating means having a magnetic field generating means is fixed to the base, and the surface of the magnetic field generating means and the conductive wire arrangement surfaces of both the first and second coils are arranged so as to face each other with a gap therebetween, and a force perpendicular to the medium surface generated in the first coil by energization;
A pickup device characterized in that the lens is driven in the first direction and the second direction by using a force parallel to the medium surface generated in the coil.