JP3274519B2 - Optical pickup device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical pickup device for recording / reproducing information on / from an information recording medium such as an optical disk and applied to an optical disk device, a magneto-optical disk device and the like.

[0002]

2. Description of the Related Art As is well known, an optical pickup device
The laser light is guided to an objective lens by an optical system, and the objective lens focuses the laser light and irradiates the information track on an optical disk as an information recording medium, and further detects the reflected light from the optical disk with a light receiving element or the like. , For recording / reproducing information.

As an example, there is a technique described in Japanese Patent Application Laid-Open No. Hei 2-68730. Japanese Patent Application Laid-Open No. 2-68730 discloses a focusing operation and a tracking operation in which a magnetic force generated by one magnetic circuit is associated with a magnetic force generated by each of a focusing coil, a tracking coil, and a seek coil. , And a seek operation are disclosed.

[0004]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 2-68.
In the technology disclosed in Japanese Patent Publication No. 730, three types of coils correspond to one magnetic circuit, and all three types of coils are incorporated in a movable optical system that irradiates a focused light onto an optical disk while moving a seek. Have been. Furthermore, the above 3
In order to generate a magnetic field in each type of coil, a power supply line for supplying power to each coil is connected to each coil.

However, when a large number of coils are mounted on a movable optical system, which is a moving body, a large number of power supply lines are required, and as the number of power supply lines increases, the assembling work becomes correspondingly difficult. In addition, the load on the movable optical system increases due to the pulling of the power supply line, which hinders the seek movement. Furthermore, the space for moving the power supply line increases, which leads to an increase in the size of the device.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide an optical pickup device in which the number of feeder lines connected to a movable optical system is reduced.

[0007]

In order to achieve the above object, the present invention provides an objective lens actuator having a focusing coil for driving an objective lens for forming an optical spot on an information recording medium at least in the direction of the optical axis. A carriage on which the objective lens actuator is mounted, a permanent magnet provided on the carriage, and a fixed coil opposed to the permanent magnet and arranged along the moving direction of the carriage; A configuration in which a plurality of element coils larger than the width of the magnet are arranged, a soft magnetic body is provided in the air core portion of the fixed coil, and power is supplied independently for each element coil facing the permanent magnet. The method is characterized in that the carriage is driven.

Further, the present invention is characterized in that the permanent magnet is arranged in a concave portion formed at the center of a substantially right angle bent portion formed on both sides of the carriage.

Further, the present invention is characterized in that a yoke portion is formed at the center of the plane of the carriage in a direction opposite to the bent portion and in parallel with the bent portion.

Further, the present invention is characterized in that the yoke is formed at two places, and a mounting portion for optical means for guiding a light beam to the objective lens, which is cut and raised in the same direction as the bent portion, is formed. .

[0011]

By adopting the above construction, it is not necessary to provide a special mounting member for mounting a permanent magnet or a coil in the concave portion at the center of the bent portion formed on the carriage having both sides bent. Easy installation becomes possible.

Further, by forming the yoke portion by cutting and raising the center portion of the carriage plane, a special member for forming the yoke portion is not required.

Further, by forming the mounting portion of the optical means by cutting and raising the center of the plane of the carriage, a special member for mounting the optical means is not required.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a plan view showing the configuration of an embodiment of the present invention. Reference numeral 1 denotes an optical disk as an information recording medium, 2 denotes a spindle motor for rotating the optical disk 1, and 3 denotes a fixed optical system. Inside the fixed optical system 3, a light source for generating laser light, a collimating lens for converting diffused light from this light source to parallel light, and further, reflected light from the optical disk 1 is detected and photoelectrically converted to a reproduced signal. A known optical system such as a light receiving element, a light receiving element for detecting a tracking shift, the size of a light spot, or the like is provided.

Reference numeral 4 denotes a movable optical system that irradiates the optical disc 1 with focused light and sends the reflected light to the fixed optical system 3 and moves in the radial direction of the optical disc 1.
Indicates seek rails formed on both sides of the seek base 5. The movable optical system 4 is placed on the seek base 5,
Further, the movable optical system 4 performs a linear motion on the seek rails 6,6.

Reference numeral 7 denotes fixed coils installed on both sides of the movable optical system 4. The fixed coil 7 is constituted by a plurality of coils (four in FIG. 1), and these element coils 7a, 7b, 7c, 7d constituting the fixed coil 7 are independently supplied with power. Is done. Further, a shaft-shaped soft magnetic body 8 is inserted into the fixed coils 7,7.

The above-mentioned spindle motor 2, fixed optical system 3, seek base 5, and fixed coils 7, 7 are fixed on a drive base 9.

Reference numeral 10 denotes an objective lens for converging parallel light from the fixed optical system 3 to form a light spot on an information track of the optical disc 1. Reference numeral 11 denotes an objective lens 10 mounted on a central portion.
A bobbin wound with a focusing coil (described later) on the side surface, 12 is a sheet metal carriage, 13 is attached to the carriage 12 at one end, and the other end is attached to the bobbin 11,
A leaf spring supporting the bobbin 11 and a yoke 14 are shown. A yoke hole 11a of the bobbin 11 is loosely fitted to the yokes 14, 14.

Reference numeral 15 denotes a permanent magnet fixed to the carriage 12 so as to face the focusing coil of the yoke 14 and the bobbin 11. These permanent magnets 15, 15 are fixed coils 7,
7 and the width of the opposing coils 7a, 7b, 7
It is smaller than the width of c and 7d. Reference numeral 16 denotes a flexible substrate that sends a current to the focusing coil.

The movable optical system 4 is constituted by the objective lens 10, bobbin 11, carriage 12, leaf spring 13, yoke 14, permanent magnet 15, and other members provided on the carriage 12. The fixed coil 7 and the permanent magnet 15 constitute a seek motor.

Reference numeral 17 denotes a deflecting prism. The deflecting prism 17 is provided on the seek base 5, deflects the optical path of the parallel light emitted from the fixed optical system 3, and guides it to the movable optical system 4.

FIG. 2 is a perspective view showing the structure of the carriage 12. As shown in FIG. 2, the carriage 12 is formed by processing a rectangular sheet metal.

In FIG. 2, reference numeral 18 denotes a slide table formed by bending both sides of the sheet metal, 19 denotes a groove formed inside the slide table 18, and 20 denotes a center of a bent portion for forming the slide table 18. A concave portion 21 formed by notching indicates a bent portion for fixing a reflecting prism (described later) for guiding laser light to the objective lens 10 shown in FIG. The bent portion 21 is formed such that the central portion of the sheet metal is cut and raised in the same direction as the slide table 18, and the cut and raised surface is perpendicular to the surface of the slide table 18.

Reference numeral 22 denotes a central hole formed in the central portion of the sheet metal by the bent portion 21. The yoke 14 is formed by cutting and raising both sides of the center hole 22 in the direction opposite to the slide table 18.

FIG. 3 is a sectional view taken along line AA of FIG. 1. Reference numeral 23 denotes a reflecting prism fixed to the bent portion 21 of the carriage 12 shown in FIG. 2, reference numeral 24 denotes a focusing coil wound around the bobbin 11, and reference numeral 25 denotes a focusing coil. Denotes a rigid sphere disposed between the groove 6a formed in the seek rail 6 and the groove 19 of the slide table 18 for smoothing the seek movement of the carriage 12. Further, permanent magnets 15 are provided in the concave portions 20 of the carriage 12.

Next, the operation of the movable optical system 4 will be described.

When a current is applied to the element coil 7b facing the permanent magnet 15, a magnetic field is generated, and the Lorentz force acts on the permanent magnet 15 by the magnetic field, so that the movable optical system 4 performs a seek movement. When the movable optical system 4 performs a seek movement,
When the permanent magnet 15 is located at a joint between the coils, for example, between the element coils 7b and 7c, the coil for generating the magnetic field is changed from the element coil 7b to the element coil 7c.
, The movable optical system 4 continuously performs seek movement.

The tracking operation is performed by moving a movable optical system 4 by sending a current to a fixed coil 7 in accordance with an output of a light receiving element for detecting a tracking shift in the fixed optical system 3. Further, the focusing operation is performed by sending an electric current to the focusing coil 24 through the flexible substrate 16 according to the output of the light receiving element for detecting the deviation of the focusing in the fixed optical system 3 and moving the objective lens 10 up and down. Will be

By employing the configuration described above, the following operation and effect can be obtained.

First, since the movable optical system 4 has no coil other than the focusing coil 24, only the focusing coil 24 needs to be connected to the flexible substrate 16. Therefore, the connection work becomes easy, and the movable optical system 4 that is lightweight can be realized because the tracking coil and the focusing coil are not provided. In addition, since the number of connections is small, there is less danger that the connection portion between the coil terminal of the focusing coil 24 and the flexible substrate 16 will be disconnected due to repetition of the seek operation.

Further, by inserting a soft magnetic material into the air core portion of the fixed coil 7, it becomes possible to attract the magnetic flux generated from the permanent magnet 15 mounted on the carriage 12 to the fixed coil 7, thereby improving the thrust. Thus, an efficient seek motor with little leakage magnetic flux can be realized.

Further, the concave portion 2 which is a mounting portion of the permanent magnet 15
The bent portions 21 which are the mounting portions of the yokes 14, 20 and the yokes 14, 14 and the reflecting prism 23 are all formed by processing a sheet metal forming the carriage 12. Therefore, the permanent magnet 15
Since no special member is required for mounting the reflection prism 23, the number of components can be reduced, and the cost can be reduced. Furthermore, the effect of mass production can be improved.

[0034]

According to the present invention as described above, the fixed coil is divided into element coils and shortened.
Since the power supply is performed independently, the internal resistance of the coil is reduced. As a result, the applied voltage can be reduced, and power can be saved.

[Brief description of the drawings]

FIG. 1 is a plan view showing a configuration of an optical disk device provided with an optical pickup device of the present invention.

FIG. 2 is a perspective view illustrating a configuration of a carriage.

FIG. 3 is a sectional view taken along line AA of FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Optical disk, 4 ... Movable optical system, 5 ... Seek base, 6 ... Seek rail, 7 ... Fixed coil, 7a,
7b, 7c, 7d: Element coil, 8: Soft magnetic material, 10: Objective lens, 12: Carriage, 14: Yoke, 15: Permanent magnet, 18: Slide table, 20: Recess, 21 ...
Bending part, 23 ... Reflection prism, 24 ... Coil for focusing.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G11B 7/085 G11B 7/09 G11B 7/095 G11B 21/02

Claims (4)

(57) [Claims] 1. A focusing machine for driving an objective lens for forming a light spot on an information recording medium at least in an optical axis direction.
An objective lens actuator having a Gukoiru, a carriage mounted with the objective lens actuator, a permanent magnet provided in said calibration <br/> ridge, opposite to the permanent magnets the key
And fixed coils arranged along the movement direction of the carriage.
Provided, larger than the width of the permanent magnets of the fixed coil, opposite
A plurality of element coils arranged side by side;
A soft magnetic material is provided in the air core portion of the
Power supply independently for each element coil
An optical pickup device for driving the carriage . 2. A substantially straight line formed on both sides of the carriage.
Insert the permanent magnet into the recess formed at the center of the corner bend.
The optical pickup device according to claim 1, wherein the optical pickup device is arranged . 3. The apparatus according to claim 3, wherein said carriage has a central part in a plane thereof.
Form a yoke that is cut and raised in the opposite direction and parallel to the bent part.
Formed by the optical pickup device according to claim 2, characterized in that the. 4. The method according to claim 1, wherein the yoke is formed at two places,
Light beam to the objective lens cut and raised in the same direction as the section.
Claims characterized in that a mounting portion of the optical means for guiding is formed.
Item 4. The optical pickup device according to item 3.