JPH06302099A - Compensation device for deviation of disk position - Google Patents

Abstract

PURPOSE:To compensate deviation of the position of a disk by rotating the disk by the prescribed angle using angle information obtained by an detecting means for angle position information, and moving the disk by the prescribed distance in the surface direction of the disk. CONSTITUTION:An axis of 1 can be made to coincide with an axis X by rotating a disk 1 by angle theta between a straight line 1 and the axis X round a point A by a rotaty mechanism as shown an arrow. Next, a disk 2 is moved by distance W by a moving means in the surface of the disk so that a point B is made to coincide with the point A by estimating an interval W between the point B and the point A. By repeating these operation several times, minute deviation of a position a between track center of the disk and the center of the rotary mechanism can be compensated surely and accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to recording / reproducing of various discs such as so-called compact discs in which information signals are recorded by unevenness, magneto-optical discs, or various optical discs and magnetic discs using phase change materials. When performing the above, the present invention relates to a disc positional deviation correcting device that corrects positional deviation between the central axis of the rotating mechanism and the center of the disk.

[0002]

2. Description of the Related Art In a compact disk (CD), a magneto-optical disk, an optical disk using a phase change material, a magnetic disk, etc., a track for writing an information signal thereof is formed as, for example, a pseudo-concentric spiral pattern.
The position on the disc is an error determined by the manufacturing accuracy,
For example, it is formed with an error of about 70 μm. In addition, the rotation mechanism of the disc requires a degree of freedom when setting the disc.

For this reason, when the disk is mounted, the center of the rotating mechanism and the center of curvature of the arc of the concentric spiral pattern of the signal track of the disk are often displaced from each other (hereinafter referred to as the track center). When reading a disc, a strong tracking servo is required so that the head can surely follow the track even if there is a large displacement between the reproducing pickup head such as an optical head or a magnetic head and the recording track. It will be.

In order to perform such a strong servo, power consumption is increased and noise may be added to the information signal itself of the disk, which is extremely weak compared with the servo current.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a device capable of simply and reliably and precisely correcting a minute positional deviation between the center of a disk track and the center of a disk rotating mechanism, which is required for tracking servo. The servo current is reduced to improve the reproduction characteristics.

[0006]

DISCLOSURE OF THE INVENTION According to the present invention, as shown in FIG. 1 which is a side view showing a schematic configuration of an example thereof, a disc 1 is provided.
The disk rotating mechanism 3 for rotating the disk, the angular position information detecting means 10, and the moving means 40 for moving the disk 1 in parallel in the in-plane direction are provided.

Further, according to the present invention, in the above-mentioned configuration, the angular position information is obtained by providing the disk rotary support 2 with angular position information and reading the angular position information. Further, according to the present invention, in the above-mentioned configuration, the angular position information detecting means 10 is incorporated in the disc rotating mechanism 3.

Further, according to the present invention, in the above-mentioned configuration, a disc in which an information signal can be recorded and erased is used as the disc. Furthermore, the present invention has the above-mentioned configuration in which a so-called compact disc, that is, a read-only optical disc (CD) in which, for example, an information signal is recorded by unevenness is used.

Further, according to the present invention, as the disc in the above-mentioned constitution, various kinds of optical discs capable of recording / erasing and reproducing are used. Furthermore, the present invention has the above-mentioned configuration in which a magnetic disk is used as the disk.

[0010]

As described above, according to the present invention, the disk rotation mechanism 3, the angular position information detecting means 10 and the moving means 40 for moving the disk 1 in the in-plane direction are provided, and the angular position information detecting means is provided. By using the angle information obtained by the means 10, the disc is rotated by a predetermined angle and moved in the in-plane direction of the disc 1 by a predetermined distance, so that the positional deviation between the rotation center of the disc rotation mechanism and the track center of the disc is accurate. It can be corrected well. This will be described below.

2A and 2B schematically show the relative positional relationship between the rotation center A of the rotation mechanism, the track center B of the disc, and the center C of the reproducing pickup head when the disc is mounted on the rotation mechanism. It is the top view shown in FIG. Further, 1 is a disc, 2 is a rotary support of the disc, a so-called turntable.

As shown in FIG. 2A, the straight line connecting the points A and C in the plane along the surface of the disk 1 with the center position A of the rotating mechanism as the origin is the x-axis, and the axis perpendicular thereto is y. Set the coordinate system as an axis.

At this time, the center position B of the track provided on the disk 1 is arranged at an arbitrary position on this coordinate, and a straight line 1 connecting this point B and the center position A of the rotating mechanism should be defined. Then, the l axis can be set.
First, as shown in FIG. 2B, the disk 1 is rotated about the point A by a rotation mechanism by an angle θ formed by the straight line 1 and the above-described x-axis as indicated by an arrow a, so that the l-axis is x. Can be aligned with the axis.

Then, the disk 1 is moved in the in-plane direction by the moving means 40 by the distance w so that the distance w between the points B and A is estimated and the point B is aligned with the point A. By performing such an operation several times, it is possible to accurately correct a minute positional deviation between the track center of the disk and the center of the rotation mechanism.

Further, in the present invention, in the above-mentioned configuration, as means for obtaining the angular position information, for example, a configuration is provided in which the angular position information is provided on a disk rotation support, that is, a so-called turntable, and the information is read out, or the disk rotation mechanism has an angle. By incorporating the position information detecting means 10, a so-called rotary encoder, the angular position information can be easily obtained.

Further, by incorporating such a position shifting device into a reproducing device for various discs or a recording / reproducing device, it becomes unnecessary to set a strong tracking servo in the reproducing pickup head portion, and the servo output can be reduced. It is possible to suppress the influence of noise or the like on the signal and improve the recording / reproducing characteristics.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. In this example, a case where the present invention is applied to a so-called compact disc position deviation correction device in which information recording is formed in advance on the disc as uneven signals is shown.

In the following description, the direction connecting the center of the rotating mechanism of the disc 1 and the center position of the reproduction pickup as described above is defined as the x-axis, and the direction orthogonal to this x-axis and extending in the plane of the disc 1 is described. The y-axis and the direction orthogonal to the surface of the disk 1 are shown as the z-axis.

In FIG. 1, reference numeral 1 denotes a disk, which is mounted on a disk rotation support 2, so-called turntable, by an air chuck or the like. Reference numeral 3 denotes a disk rotating mechanism, which is provided with an air spindle mechanism 5 in this case, and is fixed to the mounting base 4. An alternate long and short dash line _cm indicates the central axis of the disk rotating mechanism 3. Reference numeral 10 is an angular position detecting means, for example, a structure in which a scale directly provided on the disk rotation support 2 is read, or a so-called rotary encoder utilizing interference of diffracted light from the rotation grating is incorporated in the disk rotation mechanism 3 itself. And

Further, in FIG. 1, a pickup system 20 for supporting the reproduction pickup head portion 11 is arranged so as to face the reproduction surface of the disc 1. The alternate long and short dash line c _p shows the lens center of the optical head in this case. This pickup system 2
For example, 0 can be translated in the right direction in FIG. 1, which is shown by the x-axis, for example, along the surface of the disk 1 as described later.

Reference numeral 40 denotes a moving means for moving the disk 1 in parallel. The guide rail 4 is provided on the mounting base 4 on the base side thereof.
1 is provided so that the moving means 40 as a whole moves in parallel in the above-mentioned x-axis direction, that is, in the right direction along the paper surface of FIG. 1 in this case. A disc chuck mechanism 45 is provided, by which the disc 1 is attracted, moved in the z-axis direction by the z-axis stand 43, and further, coarse adjustment and fine adjustment of the movement in the x-axis direction is performed by the centering coarse / fine movement stage 42. Done

FIG. 3 shows a side view of the apparatus seen from the right in FIG. Reference numeral 21 denotes a pickup system support base, for example, the entire head support portion 25 rotates clockwise in FIG. 3 about a pickup system rotation hinge 22 fixed here, and the head is used when the disk 1 is removed. The support portion 25 can be separated from the disc 1 or the disc rotation support body 2. Reference numeral 23 denotes a stopper for rotational movement, and 24 denotes an optical axis position adjusting screw for adjusting the position of the entire pickup system in the x-axis direction and for adjusting the optical axis position of the reproducing pickup head portion 11 in this case, the optical head. .

The head supporting portion 25 is provided with an adjusting screw for adjusting the laser optical axis at right angles at the tip portion thereof, and the optical axis in the z-axis direction of the optical head is adjusted by this adjusting screw. Reference numeral 27 is a pickup system parallel moving means, which is constituted in a wheel shape, for example, and moves in parallel on the guide so that the reproducing pickup head 11 can surely move in the radial direction on the disk 1. 28 is a nut for fixing the pickup system, 29
Indicates its support. In FIG. 3, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and redundant description will be omitted.

Further, FIG. 4 shows a schematic plan view of the apparatus as viewed from above in FIG. 4, parts corresponding to those in FIGS. 1 and 3 are designated by the same reference numerals, and redundant description will be omitted. Reference numeral 30 denotes a pickup system parallel movement guide, which is interlocked with the pickup system parallel movement means 27 such as a driver's wheel to reproduce the pickup head unit 11.
Are accurately translated in parallel with the x-axis. In this case, the alternate long and short dash line c _x indicates the moving direction connecting the rotation center A of the disk rotation support 2 and the center C of the reproduction pickup head unit 11. Reference numeral 31 is a reference pin for parallelizing the pickup system, which is so fine that the head center of the reproducing pickup head portion 11 accurately crosses the radial direction on the disk 1, in this case, the radial direction of the disk rotation support 2 (turntain bull). It will be adjusted.

Hereinafter, an operation mode for correcting the displacement of the center position of the disk by using such an apparatus will be described. First, rotate the disc 1 by a predetermined angle θ described later,
As described above, the direction in which the rotation center _cm of the disk rotation mechanism 3 and the center position of the reproduction pickup head unit 11 are connected, that is, the x-axis, the rotation center of the disk rotation mechanism 3 and the track center of the disk 1 are connected. D direction, that is, FIG. 2 described above.
The 1-axis described in 1) is overlapped.

In order to obtain the above-mentioned predetermined angle θ, for example, the disk 1 is rotated once while the tracking servo amount is limited to a certain minute limited range, for example, a width of about a track pitch.
Rotate several times and check the change in tracking servo amount.
As a result, as shown in FIG. 5, the servo amount intermittently increases with respect to the rotation angle of the disk 1 with the above-described limited range as a cycle, and the tracking servo amount is 0 at the angle where the above-mentioned x-axis and l-axis match. Becomes When the rotation angle is further increased, the servo amount again follows the track and intermittently decreases with the above-described limited range as a cycle, and the servo amount becomes 0 again at the angle at which the l axis and the x axis match. Repeat the changes.
Here, the angle interval of the angle where the servo amount is 0 is 1
It becomes 80 °.

Therefore, the initial angular position of the disk is stored by the angular position detecting means 10, and the disk is rotated from this position to a position where the servo amount becomes 0, from the state described with reference to FIG. 2A to FIG. 2B. The state shown in (1), that is, the above-mentioned x-axis and l-axis can be superposed.

Further, from the number N in which the change of the servo amount becomes discontinuous in FIG. 5, the distance w in FIG. 2B, that is, the center position of the rotating mechanism and the center position of the track in the state where the x axis and the l axis are combined. The distance can be known, and by moving this distance w in the x-axis direction by the moving means 40, the rotation center of the disk rotation mechanism 3 and the track center of the disk 1 can be matched.

Alternatively, when the reproduction signal or the servo signal, the in-phase signal of the reproduction signal in the MO disk or the like is read out without applying the tracking servo at all, an error signal is schematically shown in FIG. 6 as an example. As described above, when the x-axis and the l-axis do not match with each other, the reproduction pickup head unit 4 passes across the track of the disk 1 and thus a signal is densely generated, so that the above-mentioned x-axis and the l-axis are separated from each other. In the vicinity of the matching angular position, the signal becomes sparse because the head portion 4 is substantially along the track. The interval between the angular positions where this signal is sparse is 180 °.

Therefore, also in this case, the initial rotational position of the disk is stored by the angular position information detecting means 10 in the same manner as in the case where the servo is applied while limiting the above-mentioned tracking servo amount, and the predetermined angle is stored from here. By rotating, the above-mentioned x-axis and l-axis can be matched.

Further, from the number N of signals generated by the head unit 4 passing through the track, the distance w in FIG.
That is, it is possible to know the distance between the center position of the rotating mechanism and the center position of the track in the state where the x-axis and the l-axis are combined, and by moving this distance w in the x-axis direction by the moving means 40 described above, Disk rotation mechanism 3 as in the example
The center of rotation of the disk and the track center of the disk 1 can be matched.

Needless to say, the present invention is not limited to the above-mentioned examples, and various other modifications and changes are possible. For example, the disc is not limited to the above-mentioned compact disc, and various types of discs capable of recording and erasing, for example, a magneto-optical (MO) disc and a super-resolution disc, that is, recording pits formed by unevenness, correspond to information signals. A so-called ROMSR in which a recording layer made of a phase change material is provided on the provided substrate to enable super resolution.
It is needless to say that the present invention can be applied to the misalignment correction with respect to the center position of the rotating mechanism in a disk or a magneto-optical disk whose recording layer is made of a chalcogenite phase change material or an organic phase change material, or a magnetic disk.

As described above, by incorporating the above-mentioned positional deviation compensating device in the reproducing device or the recording / reproducing device in various discs, it becomes unnecessary to apply a strong tracking servo at the time of the reproduction, and the servo current is increased. Can be reduced to suppress the influence of noise in the reproduction signal, and the recording / reproduction characteristics can be improved.

Further, according to the present invention, since the track center and the disk rotation center can be accurately aligned with each other as described above, the servo system of the reproducing pickup head part such as the optical head is provided with the x-axis and the conventional one. It is not necessary to make fine adjustment in the z-axis direction, and adjustment can be made in the x-axis direction only by a so-called feed servo system that translates the entire pickup system in the x-axis direction. A single axis can be provided in the axial direction, and the servo system device can be simplified.

[0035]

As described above, according to the present invention, the displacement between the track center of the disk and the center of the rotating mechanism can be accurately and easily and surely corrected, and the servo current can be saved. Thus, it is possible to suppress the influence of noise or the like on the information signal, and it is possible to simplify the configuration of the servo system device.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a configuration of a main part of an embodiment of the present invention.

FIG. 2 is a schematic plan view for explaining an operation mode of the present invention.

FIG. 3 is a schematic side view showing a configuration of a main part of the embodiment of the present invention.

FIG. 4 is a schematic plan view showing a configuration of a main part of an embodiment of the present invention.

FIG. 5 is a diagram showing changes in a tracking servo signal in an eccentric state.

FIG. 6 is a diagram showing changes in an error signal when servo is not applied in an eccentric state.

[Explanation of symbols]

 1 Disc 2 Disc Rotation Support 3 Disc Rotation Mechanism 4 Mounting Base 10 Angular Position Information Detection Means 11 Playback Pickup Head 20 Pickup System 40 Moving Means 41 Guide Rails 44 Arms 45 Disc Chuck Mechanisms

Claims (7)

[Claims] 1. A disc misalignment correction device comprising a disc rotating mechanism for rotating a disc, angular position information detecting means, and moving means for moving the disc in parallel in its in-plane direction. . 2. The disc position shift compensating device according to claim 1, wherein the disc rotary support is provided with angular position information, and the angular position information of the disc is obtained by reading the angular position information. A device for correcting a positional deviation of a disc, which is characterized in that 3. The disc misalignment correction device according to claim 1, wherein angular position information detecting means is incorporated in the disc rotating mechanism. 4. The disc misregistration correction device according to claim 1, wherein the disc is formed so that an information signal can be recorded and erased. 5. The disc misalignment correction device according to claim 1, wherein the disc is a compact disc. 6. The optical disk according to claim 1, wherein the optical disk is recordable / erasable and reproducible.
A disc position shift compensating device according to item 1. 7. The disk misregistration correction device according to claim 1, wherein the disk is a magnetic disk.