JPH06162540A - Optical disk device - Google Patents

Abstract

PURPOSE:To provide the optical disk device which solves the problem of the deterioration in signal quality by the mis-alignment of the disk recording surface of an optical disk and the optical axis of a beam and which can correct the inclination of the optical axis of the beam with the recording surface of the disk at a high speed with respect to a change in the warpage quantity during one round of the disk. CONSTITUTION:The flank of an objective lens holder 2 is provided with tilting coils 5a to 5d, magnets 12a to 12d which can electromagnetically drive these tilting coils, U-shaped yokes 11a to 11d, supporting materials 6a to 6h which tiltably support this objective hels holder 2, a pair of inclination detectors 13a, 13b which are disposed atop the objective lens holder 2 and detect the inclination of the optical axis of the beam released from the objective lens 1 and the recording surface of the optical disk 14. The above-mentioned tilting coils 5a to 5d are energized in accordance with the inclination error signal emitted from these inclination detectors 13a, 13b so that the objective lens holder 2 is tilted by the electromagnetic driving.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention enables high-speed tilting of a beam optical axis of an optical disk reproducing device such as a CD (compact disk) player or an LD (laser disk) player or an optical disk recording / reproducing device with respect to a disk recording surface. The present invention relates to an optical disc device that can be corrected.

[0002]

2. Description of the Related Art In an optical disk reproducing apparatus such as a CD player and an LD player, when the optical axis of a signal reproducing beam is tilted with respect to an optical disk reproducing surface, optical aberration occurs, crosstalk increases and a reproduced signal deteriorates. To do. Further, in the optical disk recording / reproducing apparatus, if the optical axis of the signal recording beam is tilted with respect to the optical disk reproducing surface, the recording signal may be deteriorated and a pit formation error may occur.

In a conventional LD player or the like, an average warp amount of one round of a disc is detected with respect to a warp in the radial direction of the disc, and a tilt motor such as a DC motor tilts the entire optical pickup to control the beam optical axis. A tilt control device was installed.

In recent years, high density recording has been advanced in optical disk devices. For high-density recording / reproduction, it is necessary to use an objective lens with a high resolution and a high NA (numerical aperture) (that is, a large aperture). The degree of aberration associated with the inclination increases in proportion to the cube of NA.

[0005]

However, in the above-mentioned conventional structure, since the tilt of the entire optical pickup is controlled by the DC motor or the like, the response is poor and it is not possible to cope with the change in the amount of warpage during one round of the disk. Had.

The present invention is to solve the above-mentioned conventional problems, and to provide an optical disk apparatus capable of correcting the inclination of the beam optical axis with respect to the disk recording surface at a high speed in response to a change in the amount of warp during one round of the disk. With the goal.

[0007]

In order to achieve this object, the optical disc apparatus of the present invention is provided with an inclination detecting means for detecting the inclination of the beam optical axis emitted from the objective lens with respect to the disc recording surface, and holding the objective lens. Objective lens holder, a support member that tiltably supports the objective lens holder, a magnetic drive unit that allows the objective lens holder to tilt, and an objective lens holder that tilts based on a tilt error signal output from the tilt detection unit. A tilt control means for correcting the tilt of the beam optical axis with respect to the disk recording surface at high speed is provided.

[0008]

According to the present invention, since the inclination of the beam optical axis with respect to the recording surface of the disk can be corrected at high speed with respect to the change in the amount of warp during the entire circumference of the disk, the occurrence of aberration can be reduced and recording and reproduction of high-quality signals can be performed. .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 4 show an embodiment of tilt control in the radial direction of the optical disc according to the present invention, and FIG. 1 is a perspective view of an optical pickup body of the optical disc apparatus.
FIG. 4 is a schematic view of a main part when there is no deviation of the beam optical axis of the tilt detecting means, FIG. 3 is a schematic view of a main part when there is a deviation of the beam optical axis of the tilt detecting means, and FIG. It is a block diagram.

The objective lens 1 of the optical system is held by the objective lens holder 2 with its periphery fixed. Focus coils 3a and 3b and tracking coils 4a and 4b are provided on the side surface of the objective lens holder 2 in the disk circumferential direction (y direction).
4c and 4d are fixed facing each other. Further, tilt coils 5a, 5b, 5c and 5d are fixed to face the side surface of the objective lens holder 2 in the disk radial direction (x direction). Eight parallel linear support members 6a, 6b, 6
c, 6d, 6e, 6f, 6g, and 6h have one end fixed to the side surface of the objective lens holder 2 and the other end fixed to the support member fixing portions 8a and 8b of the base 7, and the movable portion to the focus direction A,
It is supported so as to be movable and tiltable in three directions of a tracking direction B and a tilt direction C. The base 7 is attached to the upper part of the optical pickup body 15 and has a pair in the y direction and a pair of U-shaped yokes in the x direction. y-direction U-shaped yokes 9a, 9
b is a y-direction magnet 1 for focus and tracking drive
0a, 10b are attached, and a x-direction U-shaped yoke 11a,
X-direction magnets 12a, 12b, 12c and 12d for tilt driving are attached to 11b, 11c and 11d to form magnetic circuits, respectively. In the upper surface x direction of the objective lens holder 2, tilt detectors 13a, 13 as shown in FIG.
b is attached, and of the light emitted from the objective lens 1, condensed on the optical disc 14 and reflected, the diffracted light that does not return to the objective lens 1 can be received.

The operation of the optical disk device of the present invention will be described below. Optical disc 14 emitted from the objective lens 1
Diffracted light that does not return to the objective lens 1 of the light condensed on the light strikes the tilt detectors 13a and 13b. As shown in FIG. 2, when the objective lens holder 2 and the optical disk 14 are parallel, the two tilt detectors 13a and 13b receive the same amount of light. However, as shown in FIG. 3, when the objective lens holder 2 and the optical disk 14 are not parallel to each other, a difference in the amount of light received by the tilt detectors 13a and 13b occurs and a tilt detection signal is generated. This signal is sent to the pre-amplifier 5 shown in FIG.
The differential is taken at 1 and divided into two, and one is input to the forward rotation drive amplifier 52 to energize the tilt coils 5a and 5b. The other differential signal is input to the inverting drive amplifier 53 to energize the tilt coils 5c and 5d. Tilt coils 5a, 5
The objective lens holder 2 that holds the objective lens 1 by the electromagnetic action of b, 5c, and 5d tilts in the disc radial direction C and corrects the deviation between the optical disc 14 and the optical axis of the light beam.

When the tracking coils 4a to 4d are appropriately energized, the objective lens holder 2 is moved in parallel in the tracking direction by electromagnetic action. Therefore, it is possible to adjust the tracking of the light beam applied to the optical disc through the objective lens 1. When the focus coils 3a and 3b are appropriately energized, the objective lens holder 2 is moved in parallel in the focus direction by electromagnetic action. Therefore, the focus of the light beam with which the optical disc is irradiated through the objective lens 1 can be adjusted.

In the present embodiment, the inclination detectors 13a, 1a
By driving the tilt coils 5a, 5b and 5c, 5d based on the tilt error signal generated by 3b, the beam optical axis shift of the light emitted from the objective lens 1 can be performed at high speed with respect to the tilt change in one revolution of the rotating optical disc. Can be compensated.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 5 is a perspective view of an optical pickup body of an optical disk device showing a second embodiment of the present invention, and FIG. 6 is a configuration diagram of a control circuit. 5 and 6, constituent members having the same functions as those in FIG. 1 are designated by the same reference numerals. The difference from the configurations of FIGS. 1 and 4 is that the focus coil and the tilt coil are replaced by voice coils 105a, 105a.
b, 105c, and 105d are shared.

The operation of the optical disk device configured as described above will be described. The signals from the inclination detectors 13a and 13b are differentially divided by the pre-stage amplifier 51 and divided into two, and one of them is input to the addition drive amplifier 54 to perform addition with the focus control signal and energize the voice coils 105a and 105b. In addition, the other differential signal is input to the differential drive amplifier 55 to perform subtraction from the focus control signal and the voice coils 105c and 10c.
Energize 5d. The objective lens holder 2 which holds the objective lens 1 by the electromagnetic action of the voice coils 105a, 105b and 105c, 105d adjusts the focus of the light beam irradiated to the optical disc 14 through the objective lens 1 and tilts in the disc radial direction C, Optical disc 1
4 and the deviation of the optical axis of the light beam are corrected.

As described above, the focus coil and tilt coil are replaced by voice coils 105a, 105b, 105c, 1
In this configuration, a tilt dedicated coil and a tilt dedicated drive amplifier are required by adding one of the focus control signal and the tilt control signal divided by the control circuit to the other, and subtracting the other. Without reducing the number of parts,
The configuration can be simplified, and the cost can be reduced in addition to the effects of the first embodiment.

A third embodiment of the present invention will be described below with reference to the drawings. FIG. 7 is a plan view of an optical pickup body of an optical disk device showing a third embodiment of the present invention, FIG. 8 is a side view, FIG. 9 is a side view of essential parts,
FIG. 10 is a block diagram of the control circuit. 7 to 10, constituent members having the same functions as those in FIGS. 1 to 6 are designated by the same reference numerals.

The difference from the configurations of FIGS. 1 to 6 is that the parallel link mechanism 106a made of resin that enables the objective lens 1 to move in the focus direction and the parallel link mechanism 106a integrally molded and rotatable in the tracking direction. Further, there is a support member 106 having a tracking hinge portion 106b made of a resin that can tilt in the rolling direction, and the focus coils 3a and 3b are attached to the side surface of the objective lens holder 2 in the tracking direction with the support member 106 sandwiched therebetween. This is the point that the tracking voice coils 104a to 104d are mounted on the side surfaces of the coils 3a and 3b with an inclination angle Q.

The operation of the optical disk device configured as described above will be described. The signals of the inclination detectors 13a and 13b are differentially divided by the pre-amplifier 51 and divided into two, and one of them is input to the addition drive amplifier 54 to be added to the tracking control signal to energize the tracking voice coils 104a and 104b. In addition, the other differential signal is applied to the differential drive amplifier 55.
To the voice control coil 104c, 104d, and the voice control coil 104c and 104d are energized. Since the tracking voice coils 104a, 104b and 104c, 104d are obliquely attached, the driving force F1, F2 in an oblique direction is generated by electromagnetic action when the current I is applied,
The objective lens holder 2 holding the objective lens 1 is driven in the tracking direction to adjust the tracking of the light beam applied to the optical disc 14 through the objective lens 1 and tilt in the rotation direction in the xz plane to move the optical disc 14
And correct the deviation of the beam optical axis.

Although the objective lens holder 2 is tilted by using the tracking voice coils 104a to 104d in this embodiment, the tracking voice coils 104a to 104d are mounted without tilting and the focus coils 3a and 3b are used to perform the same operation as in the second embodiment. Any drive may be performed.

As described above, the focus coil 3 is provided on the side surface of the objective lens holder 2 with the support member 106 rotatable and tiltable in the tracking direction and sandwiching the support member 106.
By arranging a and 3b and the tracking voice coils 104a to 104d, the magnetic circuit can be paired, and the number of parts can be reduced.
The configuration can be simplified, and the cost can be further reduced in addition to the effects of the first and second embodiments.

A fourth embodiment of the present invention will be described below with reference to the drawings. FIG. 11 is a sectional view of the essential parts of an optical disk device showing a fourth embodiment of the present invention. 11, constituent members having the same functions as those in FIG. 1 are designated by the same reference numerals.

The difference from the configuration of FIG. 1 is that the objective lens holding hole 120 is provided up to almost the center of the lens holder 102, and the optical principal point S of the objective lens 1 and the lens holder 10 are provided.
That is, the driving center G that tilts 2 is matched.

With the above structure, the lens holder 1
Even if 02 is tilted, the distance between the objective lens 1 and the optical disk 14 does not change, drive leakage in the focus direction is eliminated, and stable servo characteristics can be obtained.

A fifth embodiment of the present invention will be described below with reference to the drawings. FIG. 12 is a perspective view of an optical disk device showing a fifth embodiment of the present invention. 12, constituent members having the same functions as those in FIG. 1 are designated by the same reference numerals.

The difference from the configuration of FIG. 1 is that narrow support material fixing portions 208a, 208 having a support material mounting pitch narrower than the x direction support material mounting pitch of the tapered objective lens holder 202 having a taper near the support material mounting portion.
08b, supporting materials 6a, 6b, 6c, 6d, 6
This means that e, 6f, 6g, and 6h are arranged in a V shape on the xy plane.

With the above structure, the spring force in the tilting direction can be reduced, so that the power consumption in the tilting direction can be reduced.

A sixth embodiment of the present invention will be described below with reference to the drawings. FIG. 13 is a perspective view of an optical disk device showing a sixth embodiment of the present invention. 13, constituent members having the same functions as those in FIG. 1 are designated by the same reference numerals.

The difference from the configuration of FIG. 1 is that an objective lens holder 302 with a groove having a groove in the z direction is provided at the center of the supporting member mounting portion.

A method of mounting the support material of the optical disk device configured as described above will be described. 206a to 206c, 206b and 206d facing each other among the conductive support members 206a to 206h made of a linear elastic body that can be conducted.
206e and 206g and 206f and 206h are each one elastic body before attachment. These are fixed to the support member 8
After being fixed through the support material fixing holes a and 8b, it is fixed to the side surface of the grooved objective lens holder 302 by soldering or the like. The fixed support member is cut at the center of the side surface of the grooved objective lens holder 302 by using the groove to form eight conductive support members 206a to 206h, whereby the tracking coils 4a to 4d and the voice coil 105a, 10
It becomes possible to energize 5b, 105c and 105d.

In this embodiment, the objective lens holder 30
Although the groove is provided in 2, a convex bent portion may be provided in the center of the four current-carrying support members.

As described above, four pairs of the eight parallel supporting members which oppose each other are formed by one same supporting member,
After fixing these four support materials to the objective lens holder 302 and the support material fixing portions 8a and 8b, the support materials are assembled in parallel with high precision by cutting at the side surface of the objective lens holder 302 to support them. Since there is no unnecessary resonance of the material or variation in spring force, stable servo characteristics can be obtained.

Further, by providing a groove in the z direction in the center of the side surface of the objective lens holder 302, it is possible to easily cut four supporting members into eight by utilizing these grooves, so that the working efficiency is improved and the quality is stable. And the price can be reduced.

[0034]

As described above, according to the present invention, the tilt detecting means for detecting the tilt between the optical axis of the beam emitted from the objective lens and the recording surface of the optical disk, and the objective lens holder can be operated in the tilt direction of the optical axis. A tilting means for tilting the objective lens holder and a magnetic drive means for tilting the objective lens holder and a tilt control means for tilting the objective lens holder based on the output of the tilt detecting means. On the other hand, since the beam optical axis can be corrected at high speed, it is possible to realize an excellent optical disk device capable of reducing the occurrence of coma aberration and recording / reproducing high-quality signals.

[Brief description of drawings]

FIG. 1 is a perspective view of an optical pickup body of an optical disc device according to an embodiment of the present invention.

FIG. 2 is a schematic view of a main part when there is no deviation of the beam optical axis of the tilt detecting means.

FIG. 3 is a schematic view of a main part when a beam optical axis shift of the tilt detection means occurs.

FIG. 4 is a configuration diagram of a tilt control circuit of an optical disc device according to an embodiment of the present invention.

FIG. 5 is a perspective view of an optical pickup body of an optical disc device according to a second embodiment of the present invention.

FIG. 6 is a configuration diagram of a tilt control circuit of an optical disk device according to a second embodiment of the present invention.

FIG. 7 is a plan view of an optical pickup body of an optical disc device according to a third embodiment of the present invention.

FIG. 8 is a side view of an optical pickup body of an optical disc device according to a third embodiment of the present invention.

FIG. 9 is a side view of a main part of an optical pickup body of an optical disc device according to a third embodiment of the present invention.

FIG. 10 is a configuration diagram of a tilt control circuit of an optical disc device according to a third embodiment of the present invention.

FIG. 11 is a cross-sectional view of a main part of an optical pickup body of an optical disc device according to a fourth embodiment of the present invention.

FIG. 12 is a perspective view of an optical pickup body of an optical disc device according to a fifth embodiment of the present invention.

FIG. 13 is a perspective view of an optical pickup body of an optical disc device according to a sixth embodiment of the present invention.

[Description of Reference Signs] 1 objective lens 2 objective lens holder 3a, 3b focus coil 4a-4d tracking coil 5a-5d tilt coil 6a-6h support material 7 base 8a, 8b support material fixing portion 9a, 9b y-direction U-shaped Yokes 10a to 10d y-direction magnets 11a to 11d x-direction U-shaped yokes 12a to 12d x-direction magnets 13a and 13b Tilt detector 14 Optical disk 15 Optical pickup body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Matsubara 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (9)

[Claims] 1. An objective lens for converging coherent light on at least an information recording medium, and an angular deviation between an optical axis of light emitted from the objective lens and an axis perpendicular to the information recording medium recording surface is detected. Inclination detection means, an objective lens holder that holds the objective lens, a support member that allows the objective lens holder to operate in the focus direction, the tracking direction, and the tilt direction of the optical axis, and a base that fixes the support member. An optical disc apparatus comprising: a magnetic drive unit that tilts the objective lens holder; and a tilt control unit that tilts the objective lens holder based on an output of the tilt detection unit. 2. An objective lens for converging coherent light on at least an information recording medium, and an angular deviation between an optical axis of light emitted from the objective lens and an axis perpendicular to the information recording medium recording surface is detected. An inclination detecting means; an objective lens holder for holding the objective lens; and a support member composed of a plurality of elastic bodies for enabling the objective lens holder to operate in the focusing direction, the tracking direction, and the inclination direction of the optical axis, A base for fixing a support member, a plurality of focus coils sandwiched between the support members and fixed to a side surface of the objective lens holder to drive the objective lens holder in the focus direction, and a plurality of focus coils to drive in the tracking direction. Of the tracking coil and a permanent magnet that is arranged so as to face the side surface of the focus coil and forms a magnetic circuit. And a second magnetic circuit means composed of an opposed yoke and a permanent magnet which is arranged so as to face the tracking coil and forms a magnetic circuit. An optical disk device, characterized in that the drive current flowing through a plurality of focus coils is adjusted based on the output to correct the tilt of the optical axis of the objective lens and the information recording medium. 3. An objective lens for converging coherent light on at least an information recording medium, and an angular deviation between an optical axis of light emitted from the objective lens and an axis perpendicular to the recording surface of the information recording medium is detected. An inclination detecting means, an objective lens holder for holding the objective lens, and an elastic body capable of operating the objective lens holder in a rotation direction on a focus direction and a plane perpendicular to the focus direction and an inclination direction of the optical axis. A supporting member, a base for fixing the supporting member, and a plurality of members for driving the objective lens holder in the focus direction, which are fixed to the side surface of the objective lens holder in the tracking direction with the supporting member made of an elastic body interposed therebetween. A focus coil, a tracking coil driven in the tracking direction, and a tracking coil facing the side surface in the tracking direction of the focus coil. Which are arranged in this way to form a magnetic circuit composed of a permanent magnet and a facing yoke, the drive currents flowing through the plurality of focus coils are adjusted based on the output of the tilt detecting means, and the tilt of the optical axis of the objective lens and the information recording medium is adjusted. An optical disk device characterized by correcting 4. An objective lens for converging coherent light on at least an information recording medium, and detecting an angular deviation between an optical axis of light emitted from the objective lens and an axis perpendicular to the recording surface of the information recording medium. An inclination detecting means, an objective lens holder for holding the objective lens, and an elastic body capable of operating the objective lens holder in a rotation direction on a focus direction and a plane perpendicular to the focus direction and an inclination direction of the optical axis. A supporting member, a base for fixing the supporting member, a plurality of focus coils fixed to the side surface of the objective lens holder in the tracking direction with the supporting member sandwiched therebetween, and driving the objective lens holder in the focusing direction, Tilt driving force for tilting the objective lens holder in the radial direction of the recording surface of the information recording medium and rotational driving force on a surface horizontal to the focus direction And a permanent magnet and a facing yoke which are arranged so as to face the side surface of the focus coil in the tracking direction and which form a magnetic circuit, and an opposing yoke. An optical disk device characterized by adjusting a drive current flowing through a plurality of tracking coils on the basis of the above to correct the inclination of the optical axis of the objective lens and the information recording medium. 5. The optical disk device according to claim 1, wherein the tilt drive center of the objective lens holder and the optical principal point of the objective lens are made coincident with each other. 6. The mounting pitches of a pair or more of the supporting members made of a plurality of elastic bodies that enable the objective lens holder to move in the focus direction and the tracking direction are different between the objective lens holder portion and the base portion. 3. The optical disk device according to claim 1, wherein the optical disk device is configured as described above. 7. A support member made of at least four linear elastic members is fixed to a side surface of the objective lens holder and a support member fixing portion arranged so as to sandwich the objective lens holder in the circumferential direction of the information recording medium. 3. The optical disk device according to claim 1, wherein the supporting material is divided at the center of the side surface of the objective lens holder after the step. 8. The optical disk device according to claim 1, wherein a notch is provided in the center of the side surface of the objective lens holder in the focusing direction. 9. The optical disk device according to claim 1 or 2, wherein at least four linear elastic support members are provided with a convex bent portion at the center thereof.