JP4000387B2 - Optical disk drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disc drive apparatus for optically recording, reproducing, and erasing information on optical discs such as CDs and DVDs, and in particular, recording even on optical discs having large warpage, wobbling, eccentricity, and eccentric gravity center. , Related to a configuration that enables reproduction.
[0002]
[Prior art]
In recent years, the usage trend of optical disks is shifting from CD to DVD. A DVD has a recording capacity about seven times that of a CD. In order to cope with this increase in recording capacity, it is necessary to reduce the diameter of the recording / reproducing light spot on the optical disk drive side, which shortens the wavelength of the semiconductor laser as the light source and increases the NA of the objective lens. Has been done. Furthermore, as the NA increases, correction of the tilt (tilt) of the objective lens with respect to the optical disk (hereinafter referred to as a disk) becomes an important problem. That is, when the objective lens is tilted with respect to the disc, coma aberration occurs in the light spot. The coma aberration is more likely to occur as the NA increases. The optical spot performance deteriorates due to coma aberration, and jitter during recording / reproduction (time-axis fluctuation in information data) deteriorates.
[0003]
For this reason, in the DVD drive, it is generally performed to adjust the tilt angle between the disc and the objective lens. As a representative method, a method is adopted in which a tilt sensor is provided in the optical pickup, the angle position between the optical pickup and the disk is detected, and the optical pickup is tilt-adjusted.
[0004]
In addition to the above-mentioned tilt problem, there is a problem that the optical disk drive apparatus must cope with a so-called bad disk having a large amount of warpage, surface wobbling, eccentricity, or eccentric gravity. In particular, a CD-ROM attached to a magazine or the like can be found to have a large amount of warpage, runout, eccentricity or eccentric center of gravity as described above. When such a disk is loaded and driven in an optical disk drive device, the focusing servo and tracking servo are disconnected or the servo becomes unstable. Moreover, even if the servo is turned on at the right time, the drive vibration becomes large and noise is generated, which makes the user uncomfortable.
[0005]
[Problems to be solved by the invention]
For this reason, as a conventional countermeasure against general bad disks, in order to suppress the occurrence of the above problems, when a bad disk is loaded in a drive device, the rotational speed for rotating the disk is reduced. Even when a bad disk is loaded in the drive device, it is desired that recording / reproduction is performed at a normal disk rotation speed.
[0006]
The object of the present invention is to solve the above-mentioned conventional problems, and even when a bad disk is loaded in a drive device, recording / reproduction can be performed at a normal high-speed disk rotation speed without reducing the disk rotation speed. It is an object of the present invention to provide an optical disk drive device.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is an optical disc drive apparatus for recording, reproducing and erasing information on a rotationally driven optical disc, and recording and reproducing information by irradiating the optical spot with an optical spot. , An optical pickup for erasing, a rotating chassis that supports the optical pickup so as to be movable in the radial direction of the optical disk, a fixed chassis that supports the rotating chassis so as to be rotatable, and an angle between the optical pickup and the optical disk and adjustment drive means for rotating drive the rotating chassis for adjusting the position, and a vibration detecting means for outputting a detection signal by detecting the vibration acceleration of the rotating chassis, the adjusting drive means, said A direction in which the rotating chassis moves away from the optical disc when the vibration detecting means detects an acceleration in a direction approaching the optical disc; Driven, the case where the vibration detecting means detects the acceleration in the direction away on the optical disk, characterized by driving the rotating chassis in a direction approaching to the optical disc, by this configuration, warpage, runout, eccentricity or unbalance It is possible to suppress vibration generated during rotation of a so-called bad disk having a large heart by rotating the rotating chassis, thereby reducing vibration transmitted to the optical pickup. Therefore, normal recording / reproduction with an optical pickup can be performed.
According to a second aspect of the present invention, in the optical disk drive device according to the first aspect of the present invention, the optical disk drive device further comprises control circuit means for driving the adjustment drive means based on the detection signal output of the vibration detection means. The vibration of the rotating chassis can be reliably suppressed and controlled.
[0008]
According to a third aspect of the invention, in an optical disc drive apparatus according to claim 1 or 2, wherein, to drive the adjustment drive means on the basis of the frequency component higher than a preset specific frequency in the detection signal of the vibration detecting means With this configuration, vibration correction using high-frequency components is performed using adjustment drive means that can adjust the angular position (tilt adjustment) between the optical pickup and the optical disk by rotating the rotating chassis. It becomes possible.
[0009]
According to a fourth aspect of the present invention, there is provided the optical disc drive apparatus according to any one of the first to third aspects, further comprising tilt detecting means for detecting a tilt state of the optical pickup and the optical disc and outputting the detected signal as a detection signal. The adjustment driving means is driven based on a frequency component lower than a preset specific frequency in the detection signal of the detection means. With this configuration, tilt correction by a low frequency component and vibration correction by a high frequency component are performed. This can be done using the same means.
[0010]
According to a fifth aspect of the present invention, in the optical disk drive device according to the third or fourth aspect , the specific frequency is set to substantially the same frequency as the optical disk rotation frequency. With this configuration, tilt correction and vibration correction can be performed. Can be performed using the same means.
[0011]
According to a sixth aspect of the present invention, in the optical disk drive device according to any one of the first to third aspects , the driving amount of the adjustment driving means is adjusted according to the position of the optical pickup. Even if the distance from the rotation fulcrum of the rotation chassis to the optical pickup changes, appropriate correction is performed.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of the present invention will be described below with reference to the drawings.
[0016]
FIG. 1 is a schematic configuration diagram showing a main part of an optical disk drive apparatus for explaining an embodiment of the present invention. FIG. 2 is an exploded perspective view of the main part of the optical disk drive apparatus of FIG. Is a spindle motor that is driven to rotate. Reference numeral 2 denotes an optical pickup, which is a semiconductor laser (not shown) as a light source, an objective lens 3 for condensing a light beam emitted from the semiconductor laser on the disk to form a light spot, and reflected light from the disk. A light receiving element (not shown) for detection is mounted.
[0017]
Further, the optical pickup 2 is supported by the guide rail 4 and the lead screw 5 so as to be moved and driven in the radial direction x of the disk. The lead screw 5 is driven to rotate by receiving the driving force of the seek motor 6 through the gear group 7, and a claw portion 2 a provided in the optical pickup 2 is engaged with a screw thread 5 a provided in a spiral shape in the lead screw 5. When the spiral thread 5a rotates, the claw portion 2a is pushed, and the optical pickup 2 is moved in the disk radial direction x. Each end of the guide rail 4 and the lead screw 5 is fixed to the rotating chassis 8. For this reason, the optical pickup 2 moves in the disk radial direction x on the rotating chassis 8.
[0018]
The spindle motor 1 is fixedly supported by a fixed chassis 10 shown in FIG. 2, and the rotating chassis 8 is fixed to the fixed chassis 10 so as to freely rotate. Furthermore, a first pivot portion 11 and a second pivot portion 12 are provided at opposite end portions of the rotating chassis 8, and the first pivot portion 11 and the second pivot portion are provided in the fixed chassis 10. 12 are provided with a first pivot receiving portion 13 and a second pivot receiving portion 14, respectively. The respective pivot receiving portions 13 and 14 are brought into contact with the respective pivot portions 11 and 12 of the rotating chassis 8 and pressed by the first pivot biasing spring 15 and the second pivot biasing spring 16, respectively. The rotating chassis 8 is rotatable with respect to the fixed chassis 10 with a line L connecting the pivot portions 11 and 12 as a rotation axis.
[0019]
Further, a driven piece 20 is provided in the rotating chassis 8 and is driven in the disk thickness direction y by a rotating cam 22 provided in a drive unit 21 which is an adjustment drive means. That is, the driven piece 20 is pressed against the cam surface of the rotating cam 22 by the driven piece biasing spring 23 shown in FIG. 2, and is driven by the difference in height of the cam surface of the rotating cam 22 that rotates by driving the drive unit 21. , And can be moved up and down in the y direction (disk surface direction) perpendicular to the x direction. By the vertical movement of the driven piece 20, the rotating chassis 8 is driven to rotate with respect to the fixed chassis 10 about the axis L connecting both the pivot portions 11, 12.
[0020]
As shown in FIG. 1, a tilt sensor 25 that optically detects tilt is installed near the objective lens 3 on the optical pickup 2, and is rotated on the rotating chassis 8. An acceleration sensor 26, which is a vibration detection means including an acceleration pickup that detects vibration in the normal direction on the surface of the chassis 8, is installed. Then, the detection signals from both sensors 25 and 26 are input to a CPU (Central Processing Unit) 27 which is a control circuit means to perform arithmetic processing, and then a drive control signal is output to the drive unit 21, thereby driving. The unit 21 is driven to rotate the rotary cam 22, thereby rotating the rotating chassis 8 with respect to the spindle motor 1 fixed to the fixed chassis 10 via the driven piece 20, thereby tilting ( (Tilt) correction and vibration correction described later are performed.
[0021]
The objective lens 3 provided in the optical pickup 2 receives a control drive for focusing / tracking with respect to the light beam that irradiates the recording surface of the disk by an objective lens actuator 28 including an electromagnetic drive circuit. The optical pickup 2 is provided with an error signal detector 29 including a light receiving element for detecting a focusing error signal / tracking error signal based on the reflected light from the disk of the light beam. The detection signal from the error signal detector 29 is input to a CPU (Central Processing Unit) 27 for arithmetic processing, and then a drive control signal is output to the objective lens actuator 28.
[0022]
Here, as described above, when a bad disk with large warpage, eccentricity, and eccentric gravity is loaded in the spindle motor 1 of the drive device, if the disk is rotated at a high speed, the spindle motor 1 will vibrate. , Make focusing and tracking servo unstable. In addition, vibrations cause discomfort to the user as noise.
[0023]
Therefore, it is required to suppress the vibration. With reference to the flowchart shown in FIG. 3, the operation | movement which concerns on the said vibration suppression in this embodiment is demonstrated. That is, the acceleration sensor 26 detects vibration acceleration in the rotating chassis 8, and a detection signal of the acceleration sensor 26 is input to the CPU 27 (S1). The CPU 27 outputs a drive signal according to the detection signal of the acceleration sensor 26 and drives the drive unit 21 to rotate the rotating chassis 8. As the rotating chassis 8 rotates, the optical pickup 2 approaches or moves away from the disk.
[0024]
The CPU 27 changes the rotation direction of the rotation chassis 8 according to the polarity of the detection signal of the acceleration sensor 26. That is, assuming that the axial direction of the central axis of the disk is the focusing direction, the acceleration sensor 26 detects vibrations in the focusing direction of the rotating chassis 8 and rotates the rotating chassis 8 in accordance with the detection signal, so that the light Since the pickup 2 moves in the focusing direction, the vibration of the rotating chassis 8 can be reduced.
[0025]
Specifically, when the acceleration detected by the acceleration sensor 26 is an acceleration approaching the disk (YES in S2), the CPU 27 drives the rotating chassis 8 in the direction in which the optical pickup 2 moves away from the disk ( S3). When the acceleration detected by the acceleration sensor 26 is an acceleration away from the optical disk (NO in S2), the CPU 27 drives the rotating chassis 8 in a direction in which the optical pickup 2 approaches the disk (S4). By driving the rotating chassis 8 in this way, the rotating chassis 8 can be prevented from vibrating even if the fixed chassis 10 vibrates.
[0026]
Therefore, according to the present embodiment, the vibration of the rotating chassis 8 is detected by detecting the vibration of the rotating chassis 8 and moving the rotating chassis 8 using the drive unit 21 that is a tilt correction drive source. Can be reduced. Since vibration can be suppressed in this manner, even when a bad disk is loaded in the drive device, recording / reproduction can be performed at a normal high-speed disk rotation speed without reducing the disk rotation speed. It becomes possible.
[0027]
Here, one of the problems when a bad disk is loaded in the drive device is that vibration occurs when the disk is rotated at high speed, causing the optical pickup 2 to vibrate. This vibration becomes disturbance vibration in the objective lens actuator 28 mounted on the optical pickup 2, and makes focusing and tracking control unstable. When this type of disturbance vibration is divided into a low frequency component and a high frequency component, a high frequency component is a problem. Further, this type of disturbance vibration has a waveform resembling an impact, the amplitude of a high frequency component is large, and the objective lens actuator 28 hardly follows (control is unstable). For this reason, it can be considered that the low frequency component is corrected by the objective lens actuator 28 and the high frequency component that cannot be corrected by the objective lens actuator 28 is corrected by driving the rotating chassis 8.
[0028]
For example, as shown in FIG. 4, by passing a detection signal of vibration acceleration of the rotating chassis 8 detected by the acceleration sensor 26 through a high pass filter (HPF) 31, only a frequency component higher than the characteristic frequency f is input to the CPU 27. By processing and output, it corresponds to vibration correction. By doing so, the vibration component having a frequency lower than the specific frequency f does not pass through the HPF 31, so that correction for operating the drive unit 21 is not performed. However, the low vibration component is mounted on the optical pickup 2. The objective lens actuator 28 is used for correction.
[0029]
By the way, in the configuration of the present embodiment in which the rotating chassis 8 is rotated and corrected, the tilt positional relationship between the disc and the optical pickup 2 is changed by the rotating operation of the rotating chassis 8 for correcting the vibration. However, according to the present embodiment, since the rotating chassis 8 does not follow the low frequency component of vibration, the optical pickup 2 is not inclined by the low frequency component. Since the amplitude is larger as the frequency is lower, the rotating chassis 8 does not move in the lower frequency band where the amplitude is large. Therefore, the change in the tilt positional relationship between the disc and the optical pickup 2 due to the vibration correction operation can be ignored. Degree.
[0030]
The tilt correction is intended to keep the tilt angle of the optical pickup 2 constant with respect to the disc, and the frequency to follow may be low. That is, even if the optical pickup 2 is at an arbitrary position between the inner periphery and the outer periphery of the disc, the correction should be made so that the tilt angle between the disc and the optical pickup 2 is always constant. The frequency band may be lower than the rotation frequency. Therefore, as shown in FIG. 4, by passing the tilt detection signal of the tilt sensor 25 through a low-pass filter (LPF) 32, only the frequency component lower than the specific frequency f is processed by the CPU 27 to drive the drive unit 21. To do.
[0031]
By using the HPF 31 and the LPF 32 in this way, tilt correction and vibration correction can be performed with the same drive source. That is, tilt correction can be performed in a frequency band lower than the specific frequency f, and vibration correction can be performed in a frequency band higher than the specific frequency f.
[0032]
The specific frequency f is
(1) Since most of the tilt in the radial direction of the disc (radial tilt) is below the disc rotation frequency, it is sufficient that the tilt correction follows a band below the disc rotation frequency.
(2) Want to make the rotation correction band as wide as possible.
For this reason, it is desirable that the rotational frequency of the disk be approximately the same.
[0033]
As shown in FIG. 5, it is also conceivable to use a focusing error signal detected by an error signal detector 29 in the optical pickup 2 instead of the acceleration sensor 26 in the first embodiment shown in FIG. In other words, the focusing error signal is a detection signal of the positional relationship in the optical axis direction between the disc and the objective lens 3 detected by the light receiving element from the reflected light of the light spot formed on the disc. Although the control is performed, when the bad disk is rotated, vibration of the spindle motor 1 is generated, and thus a vibration component is also included in the focusing error signal. Therefore, in order to extract this vibration component, by passing through the HPF 31, only the frequency component higher than the characteristic frequency f is input to the CPU 27 and processed, thereby driving the drive unit 21 and rotating the rotating chassis 8. It corresponds to vibration correction. On the other hand, the low frequency component is corrected by the objective lens actuator 28 as described above.
[0034]
Since the acceleration sensor 26 can be reduced in this way, the effect of reducing the cost and installation space for the acceleration sensor 26 can be obtained.
[0035]
Since the rotating chassis 8 is heavier than the objective lens 3, the correcting operation cannot be performed (moved) at a certain frequency or higher. For this reason, the objective lens actuator 28 corrects a frequency component that is too high for the rotating chassis 8 to follow.
[0036]
Further, as shown in FIG. 6, it is also conceivable to use a specific frequency in the tilt detection signal obtained from the tilt sensor 25 instead of the detection signal of the acceleration sensor 26 or the focus error signal. That is, when the bad disk is rotated, vibration is generated in the spindle motor 1, so that a vibration component is also included in the tilt detection signal detected by the tilt sensor 25. Therefore, vibration correction can be performed by operating the drive unit 21 and driving the rotating chassis 8 through the HPF 31 based on a component higher than the rotational frequency of the disk.
[0037]
Here, even if the rotating chassis 8 is inclined at the same angle as in the structure shown in the optical disk drive apparatus of FIG. 1, it is far from the rotating fulcrum (rotating axis L connecting the pivots 11 and 12). The closer the optical pickup 2 moves in the focusing direction, the smaller the amount of movement of the optical pickup 2 in the focusing direction the closer to the rotation fulcrum of the rotation chassis 8.
[0038]
In order to correct this, in the example shown in FIG. 7, an optical pickup position signal indicating the position of the optical pickup 2 in the disk radial direction is obtained by a position sensor (not shown), and gain adjustment is performed according to the position of the optical pickup 2. A gain adjustment circuit 33 is provided to adjust the gain of the vibration detection signal (the signal after passing through the HPF 31 of the tilt sensor 25 in FIG. 7). That is, the control gain is decreased as the optical pickup 2 is farther from the rotation fulcrum of the rotating chassis 8, and the gain is adjusted as the optical pickup 2 is closer to the rotation fulcrum of the rotating chassis 8.
[0039]
【The invention's effect】
As described above, according to the present invention, even when a so-called bad disk having a large amount of warpage, runout, eccentricity, or eccentric center of gravity, vibration generated during the rotation is driven by rotating the rotating chassis. Therefore, the vibration transmitted to the optical pickup can be reduced, so that normal recording / reproduction by the optical pickup can be performed even when a bad disk is loaded. It becomes possible to perform recording / reproduction at a normal high-speed disk rotation speed without reducing the speed. In addition, it is not necessary to employ a complicated configuration for the vibration correction, and a practical effect is great.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing the main part of an optical disk drive apparatus for explaining an embodiment of the present invention. FIG. 2 is an exploded perspective view of the main part of the optical disk drive apparatus of FIG. FIG. 4 is a block diagram for explaining control signal generation of the drive unit in the embodiment of the present invention. FIG. 5 is another example of drive unit control signal generation. FIG. 6 is a block diagram for explaining another example of drive unit control signal generation. FIG. 7 is a block diagram for explaining another example of drive unit control signal generation. Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Spindle motor 2 Optical pick-up 3 Objective lens 8 Rotating chassis 20 Driven piece 21 of rotating chassis Drive unit 22 Rotating cam 25 of drive unit Tilt sensor 26 Acceleration sensor 27 CPU (Central processing unit)
28 Objective lens actuator 29 Error signal detector 31 HPF (high pass filter)
32 LPF (low pass filter)
33 Gain adjustment circuit

Claims (6)

In an optical disc drive apparatus for recording, reproducing, and erasing information on a rotationally driven optical disc, an optical pickup that records, reproduces, and erases information by irradiating the optical disc with an optical spot, and this optical pickup is the diameter of the optical disc. A pivot chassis that is movably supported in a direction, a fixed chassis that pivotally supports the pivot chassis, and an adjustment that drives the pivot chassis to adjust the angular position between the optical pickup and the optical disc. Drive means, and vibration detection means for detecting vibration acceleration of the rotating chassis and outputting it as a detection signal ,
The adjustment drive means drives the rotating chassis in a direction away from the optical disk when the vibration detection means detects an acceleration in a direction approaching the optical disk, and an acceleration in a direction in which the vibration detection means moves away from the optical disk. An optical disc drive apparatus , wherein when detected, the rotating chassis is driven in a direction approaching the optical disc. 2. The optical disk drive device according to claim 1, further comprising control circuit means for driving the adjustment driving means based on a detection signal output of the vibration detection means . Optical disc drive apparatus according to claim 1 or 2, wherein the driving the adjusting drive means on the basis of the frequency component higher than a preset specific frequency in the detection signal of the vibration detecting means. Tilt detection means for detecting the tilt state of the optical pickup and the optical disk and outputting as a detection signal, and the adjustment drive based on a frequency component lower than the preset specific frequency in the detection signal of the tilt detection means optical disc drive apparatus of claim 1 or 1, wherein said driving means. Wherein the specific frequency, the optical disc drive apparatus according to claim 3 or 4, wherein the set to the optical disk rotation frequency substantially the same frequency. The optical disk drive apparatus according to any one of claims 1 to 3, wherein a drive amount of the adjustment drive means is adjusted according to a position of the optical pickup .

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