JPH02301021A - Optical disk player - Google Patents

Abstract

PURPOSE:To attain miniaturization and the reduction of a cost by providing a means to guide either a longitudinal magnet or a longitudinal yoke that is the constitutional member of a linear motor and a carriage holding an objective lens and a lens system to drive the objective lens along the recording plane of a disk. CONSTITUTION:A pair of magnetic circuits 30 consisting of the longitudinal magnet 27 and the longitudinal yokes 28 and 29 extended in parallel with the disk carrying plane 23a of a turntable 23 and are connected with each other are provided at both right and left sides of the carriage 21. A driving coil 31 is wound across the outer periphery of a sliding bearing 21a provided fixedly at both right and left end parts of the carriage 21 and fitted in the longitudinal yoke 29 slidably freely so that the center axis of the coil can be set in parallel with the moving direction of the carriage 21. Each longitudinal magnetic circuit 30 generates magnetic flux crossing with the coil 31, and comprises the linear motor. In an optical pickup comprised in such way, a current is supplied to the driving coil 31 simultaneously with the rotation of the turntable 23, and the carriage 21 is moved on the longitudinal yoke 29 with a driving force generated from the coil, then, information recorded on the disk 24 can be read.

Description

[Detailed description of the invention] Technical field The present invention relates to an optical disc player.

Background Art Optical information recording disks (hereinafter simply referred to as disks), such as video disks or digital audio disks, which are information recording media, store information by forming minute pits in spiral tracks according to the information signal. It records signals. When reading information signals recorded in this way, the disk is rotated and
A light beam is irradiated onto the track, and changes in reflected light depending on the presence or absence of the pits are converted into electrical signals and reproduced as original information signals. For this reproduction, it is necessary to accurately focus the irradiated light on the recording surface of the disc, and therefore the position of the objective lens for focusing the irradiated light on the recording surface is controlled ( focus servo)
There is a need to.

Furthermore, since the irradiation light must accurately follow the recording track, it is necessary to control the position of the irradiation light in the disk radial direction (tracking servo).

FIG. 2 shows an optical pickup device installed in a conventional optical disc player for reading information signals.

As shown in FIG. 2, the optical pickup device is
It has a carriage 1 as a holding member. Inside the carriage 1, there is a laser diode (not shown) as a light emitting element, an objective lens 5 that focuses the irradiation light emitted from the laser diode onto the recording surface of a disk 4 placed on a turntable 3, and a laser diode (not shown) as a light emitting element. An optical system including a light receiving element that receives reflected light from the recording surface and photoelectrically converts it, and a lens drive system (not shown) that controls the position of the objective lens 5 in the focusing direction and the tracking direction are provided.

The carriage 1 supports the disc supporting surface 3 of the turntable 3.
It is slidably supported via a sliding bearing 1a by a pair of guide shafts 6 extending parallel to a. A pair of longitudinal magnetic circuits 10 are disposed on both left and right sides of the carriage 1, and are composed of a longitudinal magnet 7 and longitudinal yokes 8 and 9, which extend parallel to both guide shafts 6 and are engaged with each other.

On the other hand, bobbins 1b are provided on both left and right sides of the carriage 1, and a drive coil 11 is wound around each bobbin so that the center axis of the coil is parallel to the moving direction of the carriage. The longitudinal magnetic circuit 10 generates a magnetic flux that interlinks with the drive coil 11, and together with the drive coil constitutes a linear motor that moves the carriage 1.

In the optical pickup device having the above-described configuration, the carriage 1 has a portion that fits into the guide shaft 6 and a portion that holds the drive coil 11 of the near motor. Therefore, the carriage 1 is large and heavy, and it has not always been easy to improve responsiveness. Furthermore, a large space is required for the movement of the carriage 1, which is one of the problems that must be solved in order to downsize the optical disc player.

Summary of the Invention The present invention has been made in view of the above-mentioned points, and its purpose is to provide an optical disc player that improves the responsiveness of the pickup, reduces the overall size of the player, and reduces costs. The goal is to provide the following.

The optical disc player according to the present invention uses at least one of a longitudinal magnet and a longitudinal yoke constituting a linear motor to move a holding member holding an objective lens and a lens drive system for driving the objective lens along a disc recording surface. It is characterized by its use as a means of guidance.

Embodiments Hereinafter, an optical pickup device which is a main part of an optical disc player as an embodiment of the present invention will be explained with reference to the accompanying drawings.

As shown in FIG. 1, the optical pickup device is
It has a hollow carriage 21 as a holding member.

Inside the carriage 21, there is a laser diode (not shown) as a light emitting element, and the irradiation light emitted from this laser diode is focused as a minute spot light on the recording surface of a disk 24 placed on a turntable 23. An optical system (other than the objective lens 25 is not shown) including an objective lens 25 for the purpose of irradiation and a light receiving element for photoelectrically converting the reflected light from the disk recording surface, and the objective lens 25 is aligned in the optical axis direction of the irradiated light, that is, A lens drive system that controls the position in two directions: the focusing direction (arrow F direction) and the tracking direction perpendicular to the focusing direction.
(not shown) are provided. By controlling the position of the objective lens 25 in the focusing direction, the irradiated light is accurately focused on the recording track on the disk recording surface. Further, by controlling the position in the tracking direction, the irradiation light accurately follows the recording track.

A pair of magnetic circuits 30 are provided on both left and right sides of the carriage 21, each consisting of a longitudinal magnet 27 and longitudinal yokes 28 and 29, which extend parallel to the disk carrying surface 23a of the turntable 23 and are mutually engaged. .

Each magnetic circuit 30 includes a longitudinal magnet 27 and a longitudinal yoke 2.
8 has two each, each of which is formed into a substantially flat plate shape and is fixed to each other one by one. Further, the other longitudinal yoke 28 is formed in a columnar shape, and one is provided for each magnetic circuit 30, and is arranged so as to be sandwiched between the longitudinal magnetic throat 27 and the longitudinal yoke 28. The carriage 21 is slidably supported by this cylindrical longitudinal yoke 29 via a sliding bearing 21a, thereby guiding the carriage 21 along the disk recording surface.

A longitudinal yoke 2 is fixedly installed at both left and right ends of the carriage 21.
The slide bearing 21a slidably fitted into the slide bearing 21a is formed into a cylindrical shape, and the drive coil 31 is wound around the outer periphery of the slide bearing 21a so that the center axis of the coil is parallel to the moving direction of the carriage 21. has been done. Each longitudinal magnetic circuit 30 generates a magnetic flux that interlinks with this drive coil 31, and together with the drive coil constitutes a linear motor that moves the carriage 21. Note that, as described above, the number of parts is reduced by utilizing the sliding bearing 21a that is in sliding contact with the longitudinal yoke 29 as a bobbin for winding the drive coil 31.

In the optical pickup configured as described above, current is supplied to the drive coil 31 as the turntable 23 rotates, and the drive force generated thereby causes the carriage 21 to move.
moves on the longitudinal yoke 29, and information recorded on the disk 24 is read.

In the above embodiment, the carriage 21 is guided along the disk recording surface only by the longitudinal yoke 29, but the carriage 21 may be guided by another longitudinal yoke 28 or a longitudinal magnet 27. Furthermore,
It is also possible to adopt a structure in which the carriage 21 is guided by a combination of each of these longitudinal yokes and longitudinal magnets.

Further, in the above embodiment, the car body 21 is
It has a built-in structure that includes a laser diode, an optical system consisting of a plurality of optical elements including an objective lens 25 and a light receiving element, and a lens drive system that positions the objective lens 25. It is also possible to have a configuration in which only the lens drive system is mounted on the carriage 21 and other members are provided on the fixed side.

Further, in the above embodiment, the magnet of the magnetic circuit 30 is a permanent magnet, but it can also be an electromagnetic magnet.

Effects of the Invention As detailed above, in the optical disc player according to the present invention, at least one of the longitudinal magnet and the longitudinal yoke, which are constituent members of the linear motor, is used to drive the objective lens and the lens drive system that drives the objective lens. It is used as a guide means for guiding a holding member, that is, a carriage holding the disc along the recording surface of the disc.

Therefore, it is only necessary to provide the mounting portion of the drive coil of the beam near motor on the carriage, and the carriage nozzle becomes small and lightweight, and responsiveness is improved. Furthermore, the space required for moving the carriage is small, and the optical disc player as a whole can be made smaller.

In addition, because of this configuration, members such as a guide shaft dedicated to guiding the carriage and fixing screws attached thereto, which were conventionally provided, are no longer necessary, reducing the number of parts, and improving the overall performance of the optical disc player. Further miniaturization and cost reduction have been achieved.

[Brief explanation of drawings]

FIG. 1 is a front view including a partial cross section of an optical pickup device which is a main part of an optical disc player as an embodiment of the present invention, and FIG. 2 is a front view including a partial cross section of an optical pickup device included in a conventional optical disc player. It is a front view including a partial cross section. Explanation of symbols of main parts ・21...
- Carriage 23... Turntable 24... Disc 25... Objective lens 27... Longitudinal magnet 28.29... Longitudinal yoke 30. ...Longitudinal magnetic circuit 31 ... Drive coil

Claims (1)

[Claims] a turntable, an optical system including a light emitting element and an objective lens that focuses irradiation light emitted from the light emitting element onto a recording surface of an optical information recording disk, a lens drive system that positions the objective lens, and at least the objective lens. and a holding member holding a lens drive system, and a linear magnet including a magnetic circuit consisting of a longitudinal magnet and a longitudinal yoke that extend parallel to the disk supporting surface of the turntable and at least one of which movably supports the holding member. An optical disc player having a motor.