JPS58155529A - Up, down, left and right shifting device of objective lens for optical pickup device - Google Patents

Abstract

PURPOSE:To attain a thin optical pickup device, by arragning a tracking driving section and a focus driving section in parallel with a disc and on the same line via a tracking moving frame, focusing parallel plate spring and an up/down, left/right moving section. CONSTITUTION:The tracking driving section consisting of a tracking driving permeanent magnet 18 and a tracking control square coil 17, is arranged in parallel with a focus driving permanent magnet 11 comprising a permanent magnet piece and a magnetic piece, a focus driving section comprising a focus control square coil 14, and a disk D on the same line via a tracking moving frame 16, a focusing parallel plate spring 15, and an up/down, right/left moving section 13. Thus, the size H2 to the Z axis direction of the optical pickup device is decreased, and the thickness of the optical device is made thin.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for moving an objective lens vertically and horizontally in an optical pickup device, and particularly relates to a device for moving an objective lens vertically and horizontally in an optical pickup device. The present invention relates to a device for vertically and horizontally moving an objective lens of an optical pickup device, which is disposed parallel to and on the same line as a disk through the lens, and uses a pair of rectangular bar-shaped magnets as focus drive permanent magnets.

Examples of focus and tracking control in a conventional optical pickup device are shown in Figs. 1 and 2, which show that the focus (Z-axis direction) control is controlled by a coil electromagnetic drive, and the tracking (X-axis direction) control is controlled by a coil electromagnetic drive. This is done by near motor electromagnetic drive, and the object to be driven is the objective lens 1 in both cases.

That is, a cylindrical permanent magnet 4 to which the objective lens 1 is fixed is mounted on a parallel plate spring 6 for tracking mounted inside the lens barrel 2, and a voice coil 5 is provided around the middle of the lens barrel 2, protruding from the middle part of the lens barrel 2. A cylindrical permanent magnet 4 and a voice coil 5 are arranged in a linear motor electromagnetic drive unit 7 installed in the upper part of the storage cylinder 6 and in a disc coil electromagnetic drive unit 8 installed in the middle part of the storage cylinder 6, respectively. The lens barrel 2 is held inside the housing barrel 6 using a focus parallel plate plate 9 having a circular hole in the center, and the current flowing in the coil 10 in the disc coil 5 and the linear motor electromagnetic drive section 8 is controlled. The objective lens 1 is moved in the Z-axis direction or the X-axis direction depending on the direction and size. In this way, the tracking drive section and the focus drive section are arranged in two stages perpendicular to the disk D.

In this prior art, it is desirable that the parallel plate spring 6 for tracking has a small spring constant in order to widen the range of tracking operation, and it is necessary to have a somewhat large spring constant in order to be self-supporting. Furthermore, metal is preferable because it is not affected by temperature changes. Taking all of the above into account, long metal plates are generally used.

Therefore, the size H of the optical pickup device in the Z-axis direction,
Therefore, there was a problem in that the optical pickup device was large and heavy.

Also, if the housing of the disk rotation drive motor and the optical pickup housing are on the same side, when picking up the inner circumference of the disk, the distance between the optical axis and the outer surface of the optical pickup nozzle in the disk radial direction is
(It is preferable that 1 be as small as possible, but since the focus drive section consisting of the disc coil 5 and the voice coil electromagnetic drive section 8 and the objective lens 1 are arranged concentrically, it should be made smaller by at least a certain degree. The problem was that it could not be done.

This invention was made by focusing on the problems of the prior art, and it is possible to move the tracking drive section and the focus drive section to the disk via a tracking movement frame, a parallel plate for focusing, and a vertical and horizontal movement section. The object of the present invention is to solve the above-mentioned problems by arranging the permanent magnets in parallel and on the same line, and by using a pair of rectangular bar-shaped permanent magnets as focus drive permanent magnets.

The present invention will be explained below based on the drawings.

FIG. 3 is an exploded perspective view showing an embodiment of the present invention.

First, the configuration will be described. Reference numeral 11 denotes a focus drive permanent magnet, which is a pair of square rod shapes. The focus drive permanent magnet 11 includes a permanent magnet piece 11A having a rectangular cross section, a magnetic piece 11B having a rectangular cross section larger than the permanent magnet piece 11A fixed to the upper surface of the permanent magnet piece 11A, and a magnetic piece 11B fixed to the lower surface of the permanent magnet piece 11A. A gap 11D is formed between the magnetic pieces 11B and 110. The focus drive permanent magnet 11 is fixed inside the optical pickup housing 12 on both sides #12A and 12B parallel to the tracking movement direction (X-axis direction), and its longitudinal direction is parallel to the tracking movement direction (X-axis direction). be.

By using a pair of rectangular rod-shaped focus drive permanent magnets 11, the separation distance It2 between the optical axis and the outer surface of the optical pickup housing 12 shown in FIG. 4 can be made smaller than when using a cylindrical magnet.

16 is a vertically and horizontally moving section, which is a cube. A rectangular coil 1 for focus control is arranged in the hollow part 11D of the permanent magnet 11 for focus drive in the middle part of the vertical and horizontal moving part 16.
4 are protrudingly provided around the periphery, and an objective lens 1 is attached to the center part. Reference numeral 15 denotes a parallel plate spring for focusing, one end of which is fixed to the upper right end and the lower right end of the vertical and horizontal moving unit 16, and the right end 1 of the rectangular tracking movement frame 16.
The other end is fixed to the upper part of 6R and the lower right end of 16R. And parallel plate for focus, Fne 15
is the right end of the tracking movement frame 16 and the vertical and horizontal movement section 16
is cantilevered and elastically supported freely in the focus movement direction (Z-axis direction). In addition, the parallel plate was used for focus (Z
This is to prevent the Z-axis of the objective lens 1 from tilting during control (in the axial direction). 17 is a square coil for tracking control,
One end is fixed to the inner wall of the left end 16L of the tracking movement frame 16, and the other end is formed to protrude toward the right end 16R. Reference numeral 18 denotes a tracking drive permanent magnet, which includes two permanent magnet pieces 18A and 18B, and a flat 1-shaped magnetic piece 180 sandwiched between the eight poles of the two permanent magnet pieces 18A and 18B. Magnetic pieces 18D and 1 in the shape of a planar cursor and a plane inverted cursor fixed to the N pole side of the permanent magnet piece of
It is composed of 8B.

A gap 18F is formed between the magnetic piece 180 and the magnetic piece 18D and between the magnetic piece 180 and the magnetic piece 18B. The tracking drive permanent magnet 18 has a dog-sized shape that can be housed within the tracking movement frame 16, and is fixed on a support plate 18G within the tracking movement frame 16. The support plate 18G passes through a through hole 16P bored in both side walls 16S parallel to the tracking movement force MX axis direction of the tracking movement frame 16, and its both ends are inside the both side walls 12A, 12B of the optical pickup housing 12. is fixed. Gap portion 18F of tracking drive permanent magnet 18
A rectangular coil 17 for tracking control is inserted into. Reference numeral 19 denotes a parallel plate spring for tracking, and its intermediate portion is fixed to the outer walls of the left end 16L and right end 16R of the tracking moving frame 16, and both end portions are fixed to the inner sides of both side walls 12A and 12B of the optical pickup housing 12. ing. The tracking parallel plate spring 19 elastically supports the tracking movement frame 16 in the tracking movement direction (X-axis direction). Both ends of the tracking parallel plate spring 19 are fixed to the optical pickup housing 1.
20 Mounting piece 1 protruding inside both side walls 12A and 12B
It may be set to 2C.

In this way, the tracking drive section consisting of the tracking drive permanent magnet 18 and the tracking control rectangular coil 17 includes the tracking movement frame 16, the parallel plate for focusing,
The permanent magnet 11 for focus drive and the rectangular coil 1 for focus control are
4 and the disk D are arranged parallel to and on the same line. Therefore, the size H2 in the Z-axis direction of the optical pickup device shown in FIG. 5 is reduced, and the optical pickup device can be made thinner.

Note that the longitudinal direction (X
The size in the axial direction is determined so that the focus control rectangular coil 14 does not come into contact with the focus drive permanent magnet 11 during tracking movement (X-axis direction). Furthermore, the size of the through hole 16P of the tracking movement frame 16 is determined so that the tracking movement frame 16 does not come into contact with the support plate 18 (1) during tracking movement (in the X-axis direction).

Next, the action will be explained. When the focus error signal or the tracking error signal is zero, the square coil for focus control 14 or the square coil for tracking control 1
No flow passes through the lens 7, and the objective lens 1 remains stationary at a predetermined position. If there is a focus error signal now, a current flows through the focus control rectangular coil 14. Since the direction of this current and the direction of the magnetic flux from the focus drive permanent magnet 11 are perpendicular to each other, the focus control rectangular coil 14 receives a force in the vertical direction (Z-axis direction) based on Fleming's left hand rule. The focus control rectangular coil 14 is integrated with the vertical and horizontal moving section 13, and is elastically supported by the focus parallel plate knob 15, so that it moves in the vertical direction (Z-axis direction). Therefore, the objective lens 1, which is integrated with the focus control rectangular coil 14 and the vertical and horizontal moving section 16, also moves in the vertical direction (Z-axis direction). Note that the direction and amount of movement are determined by the direction and magnitude of the current flowing through the focus control rectangular coil 14. Next, when there is a tracking error signal, a current flows through the tracking control rectangular coil 17. Since the direction of this current and the direction of the magnetic flux from the tracking drive permanent magnet 18 are perpendicular to each other, the tracking control rectangular coil 17 receives a force in the left-right direction (X-axis direction) based on Fleming's left-hand rule. The tracking control rectangular coil 17 is integrated with the tracking moving frame 16 and is elastically supported in the left-right direction (X-axis direction) by the tracking parallel plate plate 19 attached to the tracking moving frame 16. direction (X-axis direction). Therefore, the square coil 17 for tracking control, the tracking moving frame 16, and the parallel plate spring 15 for focusing
The integral objective lens 1 also moves in the left-right direction (X-axis direction) via the up-down, left-right movement section 16.

The direction and amount of movement are determined by the direction and magnitude of the current flowing through the tracking control rectangular coil 17.

Note that the focus error signal and the tracking error signal are generated by converting the laser beam of the semiconductor v--y2o into a collimator lens 21, a polarizing beam splitter 22, and so on, as shown in FIG.
'7. The wavelength plate 26 is guided to the 90° deflection mirror 24 and the objective lens 1, and the reflected light from the disk D is returned to the polarizing beam splitter 22 in the reverse order, deflected by 90°, and divided into four parts via a light shielding plate (not shown) and a converging lens. It is obtained by guiding it to the sensor.

As explained above, the present invention arranges the tracking drive section and the focus drive section parallel to the disk and on the same line via the tracking movement frame, the parallel plate for focusing, and the up/down/left/right movement section. At the same time, by using a pair of rectangular rod-shaped permanent magnets for focus driving, the optical pickup device can be made thinner, and the distance between the optical axis and the outer surface of the optical pickup housing can be reduced. This effect can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the prior art, FIG. 2 is an exploded perspective view of a tracking drive unit of the prior art, FIG. 3 is an exploded perspective view showing an embodiment of the present invention, and FIG. 4 is an embodiment of the present invention. A plan view showing an example, Fig. 5 is A-A' of Fig. 4 including the optical system.
It is a schematic cross-sectional view. DESCRIPTION OF SYMBOLS 1...Objective lens, 2...Lens barrel, 3...Tracking phase parallel plate plate, 4...Cylindrical permanent magnet, 5
...Voice coil, 6. Storage tube, 7. Linear motor electromagnetic drive section, 81.・Voice coil electromagnetic drive unit,
9... Parallel leaf spring for focus, 10... Coil,
DESCRIPTION OF SYMBOLS 11... Permanent magnet for focus drive, 12... Optical shock absorber, 13... Up/down/left/right moving unit,
14... Square coil for focus control, 15... Parallel plate nonone for focus, 16... Tracking movement frame, 17... Square coil for tracking control, 18.
...Permanent magnet for tracking drive, 19...Parallel plate spring for tracking, 20...Semiconductor laser, 21...
・Collimator lens, 22... Polarizing beam splitter, 23... - Wave plate 24... 90° deflection mirror Patent applicant Akai Electric Co., Ltd.

Claims (1)

[Claims] 1. A pair of rectangular rod-shaped focus drive permanent magnets made of a permanent magnet piece and a magnetic piece fixed to the inside of both side walls parallel to the tracking movement direction of the optical pickup housing, and a gap between the focus drive permanent magnets. A rectangular coil for focus control is placed in the central part, and an objective lens is attached to the central part. When this happens, both of 3 have their other ends fixed to the upper and lower right ends of the tracking movement frame to elastically support the vertical and horizontal movement parts, and one end to the inner wall of the left end of the tracking movement frame. A rectangular coil for tracking control with the other end protruding toward the right end side, and a tracking control rectangular coil with the other end protruding on the right end side, and a tracking movement of the optical pickup housing that penetrates through holes drilled in both side walls parallel to the tracking movement direction of the tracking movement frame. A permanent magnet piece and a magnetic piece are fixed at a position within the tracking movement frame on a support plate fixed to the inside of both side walls parallel to the direction, and a part is inserted into the hollow part of the square coil for tracking control. a permanent magnet for tracking drive consisting of; an intermediate portion fixed to the left end and right end outer walls of the tracking movement frame, and both end portions fixed to the inside of both side walls parallel to the tracking movement direction of the optical pickup housing; A device for vertically and horizontally moving an objective lens of an optical pickup device, comprising a tracking parallel plate plate that elastically supports the tracking movement frame.