JP3899693B2 - Optical disk recording / reproducing apparatus and method, and tracking servo drive apparatus and method for optical disk apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disk recording / reproducing apparatus and method and a tracking servo apparatus and method for an optical disk drive device, which perform a braking operation by a tracking servo.
[0002]
[Prior art]
So-called CDs (compact discs) on which audio signals are recorded have become widespread, and there has been an increasing demand for optical discs with high data density and a large data capacity.
[0003]
In order to increase the density of the optical disk, the recording capacity of the optical disk is increased by increasing the track pitch. For example, the track pitch of a so-called DVD (digital video disc or digital universal disc) having a capacity about 7 times that of a CD is 0.74 μm with respect to a track pitch of 1.6 μm of a CD. A DVD has a recording capacity that is approximately seven times the recording capacity of a CD due to the narrow track pitch and the use of advanced compression techniques.
[0004]
By the way, when the track pitch of the optical disk is narrowed, so-called track jumping is likely to occur due to external vibration and impact (vibration and impact are collectively referred to as shock). Therefore, in a disk drive device that drives an optical disk with a narrow track pitch, it is necessary to suppress jumping of the track due to external vibration or impact on the optical pickup (optical head).
[0005]
In a tracking servo device of a conventional optical disk drive device, a brake is applied to a lens actuator that drives an objective lens after the tracking servo is pulled in and after the tracking jump.
[0006]
Therefore, FIG. 6 showing the configuration of the tracking servo device of the conventional optical disk drive device that applies the brake to the tracking servo and FIG. 6 showing the configuration and a timing chart for explaining the operation thereof are shown. This will be described with reference to FIG. In FIG. 7, a timing chart when the light beam from the objective lens moves from the inner circumference to the outer circumference in the radial direction of the optical disk is shown on the left side of the drawing, and the timing chart when the light beam moves from the outer circumference to the inner circumference. Is shown on the right side of the figure.
[0007]
An optical disc has concentric or spiral grooves, and information signals are recorded so as to form a pit row on the bottom or land of the groove. An RF (high frequency) signal A is supplied to the envelope detection / filter processing circuit 31 as a detection signal from the optical detector of the optical pickup (optical head) of the optical disk drive device, envelope detection is performed, and the detection output is filtered. To remove noise components. The envelope detection output B from which the noise component has been removed from the circuit 31 is supplied to the zero cross comparator circuit 32 to obtain a land / groove identification signal C. These circuits 31 and 32 constitute a land / groove identification signal generation circuit.
[0008]
As the land / groove identification signal generation circuit, in addition to this, an RF signal is supplied to generate a land / groove identification signal, and a light detection signal of two light beams reflected again from the optical disk is provided. A phase difference detection circuit or the like that supplies and generates a land / groove identification signal is possible.
[0009]
The land / groove identification signal C obtained from the zero cross comparator circuit (zero cross comparator) 32 is a rectangular wave as shown in FIG. 7, and the high (H) level indicates the land portion and the low (L) level is Represents a groove. The land / groove identification signal C is supplied to the D input terminal of the D flip-flop 36, and the zero cross edge signal G of the tracking error signal D (not shown in FIG. 7) is input to the clock of the D flip-flop 36. The brake operation timing signal H is obtained at the non-inverting output terminal of the D flip-flop 36 by sampling the land / groove identification signal C with the zero cross edge signal G of the tracking error signal D. ing.
[0010]
Next, a circuit for generating the zero cross edge signal G of the tracking error signal D will be described. The tracking error signal D is supplied to the filter processing circuit 33 to obtain the tracking error signal E from which the noise component is removed, and the tracking error signal E is supplied to the zero cross comparator circuit 34. By supplying the comparison output from the zero cross comparator circuit 34 to the edge detection circuit 35, a zero cross edge signal G indicating the rising edge and the falling edge of the tracking error signal D is obtained from the edge detection circuit 35.
[0011]
The brake operation timing signal H is a rectangular wave signal as shown in FIG. 7, and the H level indicates the cutoff state of the tracking servo loop, and the L level indicates the operation state of the tracking servo loop.
[0012]
The tracking error signal D is supplied to the tracking servo filter processing circuit 38 to remove noise components, and then output as an actuator drive signal I through the changeover switch 39. A brake operation ON / OFF signal that is H level when the brake is ON, and L level when the brake is OFF, and a brake operation timing signal H are supplied to the AND gate 37, and the tracking servo filter processing circuit 38 is output from the AND gate 37. The changeover switch 39 for switching the output and the zero level (ground level) is controlled. When the output of the AND gate 37 is at the H level, the tracking error signal from which the noise component has been removed from the tracking servo filter processing circuit 38 passes through the changeover switch 39 to become an actuator drive signal, and the output of the AND gate 37 becomes L At the level, the changeover switch 39 is controlled so that the tracking error signal from which the noise component has been removed is rejected and the actuator drive signal is at the zero level (ground level).
[0013]
Referring to the actuator drive signal I shown in FIG. 7, when the brake is applied to the actuator, the relative speed between the optical disk and the lens actuator becomes close to 0, and the tracking servo is easily pulled. For this reason, the brake for the lens actuator operates when the tracking servo is retracted for the first time and when the tracking servo is retracted after the track jump. In addition, the brake operation is canceled during the recording or reproducing operation with respect to the optical disk in the tracking servo retracted state.
[0014]
Since the tracking error signal during the recording or reproducing operation on the optical disc is in the vicinity of zero, the zero cross signal F of the tracking error signal D is likely to contain noise. Further, since the fluctuation of the envelope detection signal B of the RF signal A, which is the basis of the land / groove identification signal C during recording or reproducing operation on the optical disc, is small, the land / groove identification signal C has a noise component near its zero level. Is easily included. Due to the influence of noise components of these signals, the braking servo is released during recording or reproduction on the optical disc and the tracking servo is released, thereby increasing the tracking error.
[0015]
[Problems to be solved by the invention]
As described above, in the tracking servo device of an optical disk drive device that drives an optical disk with a small track pitch and a large recording capacity, the tracking serve comes off due to a large external vibration or large impact on the optical pickup (optical head), and the track Jumping easily occurs. Once a track jump occurs, the tracking servo that was applied in the tracking servo range of the tracking error signal will be applied in the tracking non-servo range of the opposite polarity to the tracking servo range of the tracking error signal. Jumping will occur frequently. In order to suppress such a track jump to a minimum, when a track jump occurs, it is necessary to remove the servo for the lens actuator and apply a brake to the lens actuator. This brake minimizes track jumping, shortening the return time to the tracking servo state after occurrence of external vibration and impact on the optical pickup and suppressing excessive driving of the lens actuator. Thus, the lens actuator can be prevented from malfunctioning. When an external vibration or impact is applied to the optical pickup, it is necessary to quickly brake the lens actuator.
[0016]
However, since the track pitch is narrowed, when an external vibration or impact is applied, it is easy to cause a so-called track jump out of the track range. That is, in the recording / reproducing of an optical disk having a high data capacity, the track pitch is narrow, and therefore, it is easily affected by external vibration and impact.
[0017]
In particular, when a large shock is applied to the apparatus from the outside, the tracking servo tends to come off and track skipping occurs. Once a track skip occurs, an unnecessary portion of the output outside the tracking servo range is added, so that the track skip is successively increased.
[0018]
Therefore, in the recording / reproducing of an optical disk having a high data capacity, it is necessary to devise a method for reducing the influence even if a shock is applied.
[0019]
To keep track skipping to a minimum, the tracking servo must be braked. By minimizing track skipping, the recovery time after an external shock can be shortened, and excessive driving of the actuator can be suppressed to prevent device failure. For this reason, a device for switching so that the brake operation immediately works against the shock is required.
[0020]
The present invention has been made in view of the above circumstances, and an optical disc recording / reproducing apparatus and method for preventing a track jump by operating a brake operation when a shock is applied, and a tracking servo apparatus for an optical disc drive apparatus, It aims to provide a method.
[0021]
[Means for Solving the Invention]
In order to solve the above-described problems, an optical disc recording / reproducing apparatus according to the present invention is an optical disc recording / reproducing apparatus that records and / or reproduces an information signal with respect to an optical disc, and is disposed to face the optical disc. An optical pickup having an objective lens for condensing and irradiating laser light, a light receiving means for receiving return light from the optical disc, and an objective lens driving means for driving the objective lens at least in the radial direction of the optical disc, Displacement signal generation for generating a displacement signal corresponding to the radial displacement from the recording track on the optical disc closest to the condensing point of the laser beam to the condensing point based on the light detected by the light receiving means And the objective lens driver in a direction to recover the displacement based on a displacement signal from the displacement signal generating means. A servo means driven by the means; a brake signal generating means for generating a brake signal obtained by removing unnecessary components from the displacement signal from the displacement signal generating means for drawing a servo operation of the servo means; and Brake means for driving the objective lens based on a brake signal from the brake signal generating means in the driving direction of the objective lens based on a displacement signal, and impact detection means for detecting an impact applied from the outside to the optical pickup And control means for switching from the servo means to the brake means only when the impact level detected by the impact detection means exceeds a predetermined value.
[0022]
In other words, this optical disc recording / reproducing apparatus detects a shock applied from the outside, and when a shock that may cause the tracking servo in the radial direction of the optical disc to come off is detected, the tracking servo brake operation is performed until the influence is eliminated. To do.
[0023]
An optical disc recording / reproducing method according to the present invention includes an objective lens that is disposed opposite to an optical disc and collects and irradiates laser light on the optical disc, a light receiving means that receives return light from the optical disc, and the objective lens In an optical disc recording / reproducing apparatus that records and / or reproduces an information signal to / from an optical disc by using an optical pickup having at least an objective lens driving means for driving the optical disc in the radial direction of the optical disc, A displacement signal generating step for generating a displacement signal corresponding to the radial displacement from the recording track on the optical disc close to the condensing point based on the light detected by the light receiving means; and the displacement signal generating step Servo that drives the objective lens by the objective lens driving means in a direction to recover the displacement based on a displacement signal from A brake signal generation step for generating a brake signal by removing unnecessary components from the displacement signal from the displacement signal generation step to remove the servo operation of the servo step, and the objective based on the displacement signal in the servo step. A brake process for driving the objective lens based on a brake signal from the brake signal generation process in a driving direction of the lens; an impact detection process for detecting an impact applied from the outside to the optical pickup; And a control step of switching from the servo operation of the servo step to the brake operation of the brake step only when the impact level detected in the impact detection step exceeds a predetermined value.
[0024]
The tracking servo device of the optical disc driving apparatus according to the present invention is a lens actuator that drives the objective lens by detecting a tracking error signal of a focused light beam emitted from the objective lens of the optical head and applied to the optical disc including the groove. And a tracking servo timing signal generating means for generating a brake operation timing signal based on the tracking error signal and the land / groove identification signal of the focused light beam. In the tracking servo device of the optical disk drive device, in which the tracking servo device is braked, shock detecting means is provided in the optical head, and the block is detected according to the level of the shock detection signal from the shock detecting device. It is obtained so as to control the supply to the tracking servo means over key operation timing signal.
[0025]
The tracking servo method of the optical disk drive apparatus according to the present invention is a lens actuator that drives the objective lens by detecting the tracking error signal of the focused light beam that is emitted from the objective lens of the optical head and is irradiated on the optical disk including the groove. And a tracking servo timing signal generating means for generating a brake operation timing signal based on the tracking error signal and the land / groove identification signal of the focused light beam. In the tracking servo device of the optical disk drive device that applies the brake to the tracking servo means, the brake operation timing signal is set according to the level of the shock detection signal obtained by detecting the shock of the optical head. It is obtained so as to control the supply to the serial lens actuator.
[0026]
According to the present invention, the supply of the brake operation timing signal to the tracking servo means is controlled in accordance with the level of the shock detection signal from the shock detection means.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0028]
As an embodiment of an optical disk recording / reproducing apparatus and method and a tracking servo apparatus and method for an optical disk drive apparatus according to the present invention, an optical disk recording / reproducing apparatus for recording / reproducing an information signal on / from an optical disk will be described. This optical disk recording / reproducing apparatus has a tracking servo apparatus of an optical disk driving apparatus, which will be described later, as a part of its configuration.
[0029]
As shown in FIG. 1, the optical disc recording / reproducing apparatus has a chucking member 2 that sandwiches and fixes the central portion of the optical disc 1, and a spindle motor 3 that rotationally drives the optical disc 1 via the chucking member 2. Yes.
[0030]
The optical disc recording / reproducing apparatus is disposed opposite to the optical disc 1 to focus the laser beam on the signal recording surface of the optical disc and irradiate the objective lens 5 with respect to the optical disc 1. An optical pickup 4 provided with an actuator 6 which is an objective lens driving means for driving in a focus direction which is a contact / separation direction with respect to a signal recording surface and a tracking direction which is a radial direction of the optical disc 1, and a shock attached to the optical pickup 4 That is, it has the shock sensor 7 which is an impact detection means which detects an impact. The optical pickup includes a light receiving unit (not shown) that receives the return light from the optical disc 1.
[0031]
Further, the optical disc recording / reproducing apparatus includes a shock level comparison unit 12 that outputs a result of comparing a shock sensor output L from a shock sensor 7 that is a shock detection means for detecting a shock from the outside and a predetermined reference level, and a shock level. It has a hold unit 13 that holds the output from the comparison unit 12, a control unit 11 that controls the detection of shock, and an OR unit 21 that performs an OR operation on the outputs from the hold unit 13 and the control unit 11.
[0032]
Further, the optical disc recording / reproducing apparatus receives the RF signal A and the tracking error signal D from the optical pickup 4 and generates a brake operation timing signal H from the brake operation timing signal generator 8 and the brake operation timing signal generator 8. And an AND unit 22 that performs an AND operation on the brake operation timing signal H and the brake operation on / off signal K from the OR unit 21.
[0033]
Then, the optical disc recording / reproducing apparatus performs tracking servo filter processing for performing tracking servo filter processing from the tracking error signal D which is the displacement signal from the light receiving unit (not shown) of the optical pickup 4 and the displacement signal detection unit following the optical pickup 4. Unit 9, a switch 23 that turns on / off the output from the tracking servo filter processing unit 9 according to the output N from the AND unit 22 and shuts off the unnecessary part, and the tracking servo whose unnecessary part is cut off by the switch 23 9 and an actuator drive circuit unit 10 that drives the actuator by an output I from the circuit 9.
[0034]
Here, the control unit 11, the shock level comparison unit 12, the hold unit 13, the OR unit 21, the AND unit 22, and the switch 23 include a tracking servo when the magnitude of an external shock exceeds a predetermined value. Control means for switching from operation to brake operation is constructed.
[0035]
Thus, in the optical disk recording / reproducing apparatus, the optical disk 1 is fixed by the chucking unit 2 and is rotationally driven by the spindle motor 3. The laser light emitted from the optical pickup 4 is focused on the optical disk 1 and is given a laser power for recording during recording and a laser power for reproduction during reproduction. The objective lens 5 in the optical pickup unit 4 is driven by an actuator 6. That is, focus servo in the contact / separation direction of the optical disc 1 and tracking servo in the radial direction of the optical disc 1 are performed in order to focus the laser beam on the signal recording surface which is the data surface of the optical disc 1 and follow the target track.
[0036]
The optical disk recording / reproducing apparatus is disposed opposite to the optical disk 1 to focus and irradiate laser light onto the optical disk, and an actuator 6 that drives the objective lens 5 in the focus direction and tracking direction of the optical disk. The optical pickup 4 having
[0037]
The tracking servo of this optical disc recording / reproducing apparatus recovers this displacement in accordance with the displacement in the tracking direction from the track closest to the condensing point on the optical disc 1 of the laser beam irradiated from the objective lens 5 to the condensing point. In the direction, the actuator 6 is driven in the tracking direction.
[0038]
That is, the actuator 6 is driven in accordance with the tracking error signal given corresponding to the displacement so that the objective lens 5 recovers the displacement.
[0039]
The optical disk recording / reproducing apparatus prevents the tracking servo from coming off when the magnitude of shock detected by the shock sensor 7 which is a shock detection means provided in the optical pickup 4 exceeds a predetermined value. Turn on the brake action.
[0040]
In this braking operation, unnecessary signals for pulling the tracking servo are removed from the tracking error signal, the direction of the tracking direction component of the objective lens 5 for pulling the tracking servo, and the tracking servo drives the objective lens 5 in the tracking direction. This is due to the brake means that turns on the tracking servo only when the direction to perform is the opposite direction.
[0041]
Here, in order to increase the density of the optical disc 1, the objective lens 5 disposed on the optical pickup 4 so as to face the optical disc 1 is a two-group lens that realizes a high numerical aperture (NA). Can be used.
As shown in FIG. 2, the two-group lens includes two lenses, a front lens 103 having a flat surface on the optical disk side 1 and an aspheric curved surface on the objective lens 104 side, and an objective lens 104 being an aspheric lens. It is composed of As the front lens 103, a hemispherical lens composed of a plane and a spherical surface can be used.
[0042]
In the second group lens, the front lens 103 and the objective lens 104 are driven by an actuator 106 and an actuator 107.
[0043]
The actuator 106 is configured to move the front lens 103 relative to the objective lens 104 in the optical axis direction (vertical direction in the figure). The voltage applied to the actuator 106 and the front lens 103 The objective lens 104 is moved in the optical axis direction (focus direction).
[0044]
The actuator 107 is a biaxial actuator, and is moved in a direction perpendicular to the track of the optical disc 1 (tracking direction). The actuator 107 is supplied with drive signals in the focus direction and the tracking direction, thereby adjusting the distance of the second group lens (the front lens 103 and the objective lens 104) from the optical disk 1 and also directing the laser beam to the track. To move vertically.
[0045]
According to such a configuration, the actuator 107 can adjust the distance between the objective lens 104 and the optical disc 1 in the same manner as the conventional two-group lens, and the actuator 106 allows the front lens 103 and the objective lens 104 to be adjusted. The interval of can be adjusted. By adjusting the distance between these two lenses and the distance between the objective lens 104 and the optical disc 1 according to the thickness of the disc substrate 102 of the optical disc 1, the occurrence of spherical aberration can be suppressed.
[0046]
This two-group lens uses a light source having a wavelength of 680 nm or more and has a high NA of 0.7 or more, for example, 0.81. The working distance between the objective lens 104 and the optical disc 1 is 560 μm or less, for example, 100 μm. Therefore, the second group lens has a high NA, a small gap between the second group lens and the optical disk, and aberrations are reduced.
[0047]
Next, an example of the optical disc 1 will be described with reference to FIG.
The optical disk 1 uses a stamper that realizes pitch and pitch unevenness, and creates a replica substrate 110 by an injection molding method. Subsequently, a recording film or a reflective film 111 is formed on the signal surface of the replica substrate 110. For example, when the optical disk is a ROM, a reflective film such as Al is formed.
[0048]
Further, a cover layer 112 is formed thereon. For example, a cover layer is formed by dropping and extending an ultraviolet curable resin, that is, a UV resin, on a film-forming layer of a substrate formed with any structure formed as described above. Alternatively, a cover layer may be formed by bonding a paris carbonate sheet with an ultraviolet curable resin.
[0049]
Examples of the thickness of the light transmission layer of the optical disk thus produced include 3 to 177 μm.
[0050]
Next, the operation of the optical disc recording / reproducing apparatus will be described with reference to the circuit portion in FIG. 1 and the signal waveforms of the respective portions shown in FIG.
[0051]
The shock sensor 7 attached to the optical pickup 4 outputs a shock sensor output signal L as shown in (a) in the figure in accordance with the shock detected by the shock sensor 7.
[0052]
The shock level comparison unit 12 outputs the result of comparing the shock sensor output L from the shock sensor 7 with a preset positive and negative reference level (± reference level). Normally, an external shock is vibrational, and the output from the comparison unit 12 continues with a pulse train while the shock continues.
[0053]
In the hold unit 13, a time T that is determined by estimating a time during which the influence of the shock is reduced or a time during which the shock is reduced is estimated. ₁ In the meantime, the output of the shock level comparison unit 12 is held.
[0054]
The control unit 11 outputs the brake operation on / off. When the signal of the hold unit 13 is input to the OR unit 21 and the OR operation is performed, ON / OFF of the brake operation during recording / reproducing is performed by the hold unit 13. Will follow the output.
[0055]
Therefore, the brake operation on / off signal K shown in (b) in the figure is at a high level until a shock is applied and the influence is alleviated, and the brake operation is turned on during that time. That is, even after the shock sensor output L falls below the reference level of the shock level comparison unit 12 and the pulse falls, the brake operation on / off signal K is further time T ₁ The high level is maintained throughout.
[0056]
The brake operation timing signal generation unit 8 generates a brake operation timing signal H shown in (d) of the figure using the RF signal A from the optical pickup 4 and the tracking error signal D shown in (c) of the figure. .
[0057]
The tracking servo filter processing unit 9 receives a tracking error signal D from the optical pickup 4. The output from the tracking servo filter processing unit 9 is blocked by the switch 23 that is ON / OFF controlled by the AND output N. As a result, the output of the actuator drive signal I whose unnecessary portion is cut off by the switch 23 becomes zero in the unnecessary portion, and works so that the brake is applied only in the direction in which the lens jumps due to the shock.
[0058]
As described above, the brake signal for performing the brake operation by driving the actuator 6 is obtained by removing unnecessary components for pulling the tracking servo. This brake operation signal corresponds to the actuator drive signal I.
[0059]
As described above, the optical disc recording / reproducing apparatus can minimize the track skipping by the above-described braking operation even if a shock is applied from the outside and the tracking servo is released and the track skipping occurs. Redrawing can be performed.
[0060]
Next, a series of steps related to the optical disc recording / reproducing method will be described with reference to the flowchart shown in FIG.
[0061]
This optical disc recording / reproducing method includes an objective lens that is disposed opposite to an optical disc and condenses and irradiates laser light on the optical disc, and an optical pickup having an actuator that drives the objective lens at least in the tracking direction of the optical disc. The actuator in a direction to recover the displacement in accordance with the displacement in the tracking direction from the track on the optical disc closest to the condensing point on the optical disc of the laser light irradiated from the objective lens Is recorded and / or reproduced with respect to the optical disc using a tracking servo that drives the disc in the tracking direction.
[0062]
In the first step S1, an output from a shock sensor disposed in the optical pickup is detected. Then, the process proceeds to the next step S2.
[0063]
In step S2, control is performed so that the brake process is executed only when the shock level detected in step S1 exceeds a predetermined value. Then, the process proceeds to the next step S3.
[0064]
In step S3, a braking operation in which the tracking servo is turned on only when the direction in which the actuator drives the objective lens in the tracking direction by the tracking servo is opposite to the tracking direction component of the objective lens speed. I do. Then, a series of steps related to the optical disc recording / reproducing method is completed.
[0065]
As described above, in the optical disk recording / reproducing method, even if a shock is applied from the outside and the tracking servo is released and the track skip occurs, the track skip is minimized by the above-described brake operation, and the tracking servo is immediately performed. Can be redrawn.
[0066]
Next, the brake operation of the optical disc recording / reproducing apparatus will be described with reference to the brake operation circuit shown in FIG. 6 and the waveforms of the respective parts of the brake operation circuit shown in FIG. In this brake operation, the brake operation is performed for the tracking servo pull-in and the actuator control after the track jump.
[0067]
In the brake operation circuit, the envelope detection filter unit 31 performs envelope detection on the RF signal A and outputs a signal B from which noise has been removed by filter processing. The zero cross comparator 32 generates a land / group identification signal C by zero cross comparing the signal B from the envelope detection filter 31. The land / group identification signal C is a high level signal in the land portion and a low level signal in the group portion.
[0068]
Here, the land / group identification signal C is generated from the envelope detection of the RF signal A. However, the land / group identification signal C can also be generated by processing the RF signal A by LPF (Low Pass Filter), or from the phase difference of the push-pull signal of the side beam. You can also.
[0069]
The zero-cross edge signal G is obtained by filtering the signal E obtained by filtering the tracking error signal D by the filter processing unit 33 to remove noise into the signal F by zero-crossing the signal by the zero-cross comparator 34. It is obtained by detecting rising / falling edges in the unit 35.
[0070]
The operation timing signal H of the brake operation is obtained by fetching the land / group identification signal C with the zero cross edge signal G of the tracking error signal D in the D flip-flop 36.
[0071]
That is, while the brake operation timing signal H is at a high level, the tracking servo loop is interrupted and the brake is applied by cutting unnecessary portions. This is shown in the actuator drive signal I.
[0072]
When the brake is applied by the actuator drive signal I, the relative speed of the lens actuator that drives the optical disk and the objective lens becomes close, and the tracking servo is easily pulled. For this reason, the brake operation circuit was used when the tracking servo was pulled in for the first time and when the tracking servo was pulled after the track jump.
[0073]
However, this brake operation function is turned off during recording and reproduction after the tracking servo is pulled. During recording and reproduction, the track error is near zero, and the zero cross signal of the tracking error signal is likely to generate noise. Further, since the fluctuation of the signal that is the source of the land / groove identification signal C is small, noise is likely to occur at the zero comparator portion of the land / groove identification signal C. This is because if the brake operation occurs during recording / reproduction under the influence of these signal noises, the servo is released and the track error increases.
[0074]
As described above, the brake signal for performing the brake operation by driving the actuator is obtained by removing an unnecessary component for drawing the tracking servo. This brake operation signal corresponds to the actuator drive signal I.
[0075]
Here, assuming that the brake is not working, the actuator drive signal I is changed in the same way as the tracking error signal D, and the brake does not work in DC, and the lens repeats track jumping one after another. Cause problems.
[0076]
Compared to the brake operation circuit described above, the optical disc recording / reproducing apparatus described above uses the AND unit 22 to generate the brake operation timing signal H and the brake operation on / off signal K generated from the shock sensor output L for detecting a shock. By performing an AND operation, pulses due to erroneous detection are removed, and the brake operation can work only at the time of shock.
[0077]
In addition, since the optical disc recording / reproducing apparatus can minimize the skipping of a track even in response to a shock and shorten the system recovery time, for example, when the recorded data is an image sound, an image or sound Can be stopped in an instant.
[0078]
Further, in the optical disk recording / reproducing apparatus, depending on the system, when the recovery time is short, it can be absorbed by a buffer in the system, and interruption can be prevented.
[0079]
In the brake operation circuit shown in FIG. 6, the envelope detection filter processing unit 31, the zero cross comparison unit 32, the filter processing unit 33, the zero cross comparison unit 32, the edge detection unit 35, and the D flip-flop 36 The brake operation timing operation generation unit 8 is configured to generate an operation timing signal for this timing.
[0080]
In this optical disk recording / reproducing apparatus, the configuration of each block is represented as a circuit unit, but may be realized by performing arithmetic processing by a DSP (digital signal processor).
[0081]
The optical disk recording / reproducing apparatus of the present embodiment detects a tracking error signal of a focused light beam emitted from an objective lens of an optical head and applied to an optical disk having a groove, and serves as a lens actuator that drives the objective lens. Tracking servo means to be supplied, and break operation timing signal generating means for generating a break operation timing signal based on the tracking error signal and the land / groove identification signal of the focused light beam. A tracking servo device of an optical disk drive device that applies a brake to the tracking servo means is included as a component.
[0082]
In the tracking servo device configuration which is the premise, in the tracking servo device of the optical disk drive device, the optical head is provided with shock detection means, and the break operation timing is determined according to the level of the shock detection signal from the shock detection means. Controls the supply of signals to the tracking servo means.
[0083]
It also detects the tracking error signal of the focused light beam that is emitted from the objective lens of the optical head and applied to the optical disk with the groove, and supplies the tracking error signal to the lens actuator that drives the objective lens to perform tracking servo. And a tracking servo method of an optical disk drive apparatus that generates a break operation timing signal based on the land / groove identification signal for the focused light beam and brakes the tracking servo by the brake operation timing signal. A pre-requisite configuration.
[0084]
The present invention controls the supply of the break operation timing signal to the lens actuator in accordance with the level of the shock detection signal obtained by detecting the shock of the optical head in the presupposed configuration.
[0085]
Although the optical disk recording / reproducing apparatus has been described as the present embodiment, the tracking servo apparatus and method of the optical disk driving apparatus according to the present invention are not limited to this optical disk recording / reproducing apparatus.
[0086]
【The invention's effect】
As described above, in the optical disk recording / reproducing apparatus, when a shock is detected, a braking operation is performed using the tracking servo. Therefore, even if the tracking servo is released and the track skip occurs, the track skip is minimized and the track skip is immediately restarted. Retraction can be performed.
[0087]
Also, according to the optical disk recording / playback method, when a shock is detected, the tracking servo is used to perform the braking operation. Therefore, even if the tracking servo is released and the track skip occurs, the track skip is minimized and the retraction is performed immediately. be able to.
[0088]
Further, according to the present invention, the tracking servo that detects the tracking error signal of the focused light beam irradiated to the optical disk having the exit groove from the objective lens of the optical head and supplies it to the lens actuator that drives the objective lens. And a brake operation timing signal generating means for generating a brake operation timing signal based on the tracking error signal and the land / groove identification signal of the focused light beam. The head is provided with shock detection means, and the supply of the brake operation timing signal to the tracking servo means is controlled in accordance with the level of the shock detection signal from the shock detection means. Opposition It suppresses the track jump occurs due to, it is possible to obtain a tracking servo apparatus of an optical disk driving apparatus capable of quickly performing a return to a normal tracking servo status from the track jump state.
[0089]
According to the present invention, the tracking error signal of the focused light beam emitted from the objective lens of the optical head and applied to the optical disk provided with the groove is detected and supplied to the lens actuator that drives the objective lens for tracking servo. The tracking servo of the optical disc driving apparatus that generates a brake operation timing signal based on the tracking error signal and the land / groove identification signal of the focused light beam, and brakes the tracking servo based on the brake operation timing signal. In the method, the supply of the brake operation timing signal to the lens actuator is controlled in accordance with the level of the shock detection signal from the shock detection means provided in the optical head. Ri is suppressed track jump occurs, it is possible to obtain a tracking servo method of an optical disk driving apparatus capable of quickly performing a return to normal tracking servo status from the track jump state.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of an optical disc recording / reproducing apparatus.
FIG. 2 is a cross-sectional view showing a configuration of a second group lens.
FIG. 3 is a cross-sectional view of an optical disc.
FIG. 4 is a timing chart showing signal waveforms at various parts of the optical disc recording / reproducing apparatus.
FIG. 5 is a flowchart showing a series of steps according to the optical disc recording / reproducing method.
FIG. 6 is a block diagram showing a brake operation circuit.
FIG. 7 is a diagram showing signal waveforms at various parts of the brake operation circuit.
[Explanation of symbols]
1 optical disk, 4 optical pickup, 6 actuator, 7 shock sensor, 10 actuator drive circuit

Claims (6)

In an optical disc recording / reproducing apparatus for recording and / or reproducing information signals to / from an optical disc,
An objective lens that is disposed opposite to the optical disk and collects and irradiates laser light on the optical disk, a light receiving means that receives return light from the optical disk, and drives the objective lens at least in the radial direction of the optical disk An optical pickup having an objective lens driving means;
A displacement signal generated based on the light detected by the light receiving means, a displacement signal corresponding to the radial displacement from the recording track on the optical disc closest to the condensing point of the laser light to the condensing point Generating means;
Servo means for driving the objective lens by the objective lens driving means in a direction to recover the displacement based on a displacement signal from the displacement signal generating means;
Brake signal generating means for generating a brake signal from which unnecessary components are removed in order to draw the servo operation of the servo means from the displacement signal from the displacement signal generating means;
Brake means for driving the objective lens based on a brake signal from the brake signal generating means in a driving direction of the objective lens based on a displacement signal in the servo means;
An impact detection means for detecting an impact applied from the outside to the optical pickup;
An optical disk recording / reproducing apparatus comprising: a control means for switching from the servo means to the brake means only when an impact level detected by the impact detection means exceeds a predetermined value. 2. The optical disc recording / reproducing apparatus according to claim 1, wherein the control means continues the brake means for a predetermined time from the time when the level of the impact detected by the impact detection means does not exceed a predetermined value. An objective lens that is disposed opposite to the optical disk and collects and irradiates laser light on the optical disk, a light receiving means that receives return light from the optical disk, and drives the objective lens at least in the radial direction of the optical disk In an optical disc recording / reproducing apparatus for recording and / or reproducing information signals on an optical disc using an optical pickup having an objective lens driving means,
A displacement signal generated based on the light detected by the light receiving means, a displacement signal corresponding to the radial displacement from the recording track on the optical disc closest to the condensing point of the laser light to the condensing point Generation process,
A servo step of driving the objective lens by the objective lens driving means in a direction of recovering the displacement based on a displacement signal from the displacement signal generating step;
A brake signal generating step for generating a brake signal from which unnecessary components are removed in order to draw the servo operation of the servo step from the displacement signal from the displacement signal generating step;
A brake step of performing a braking operation for driving the objective lens based on a brake signal from the brake signal generation step in a driving direction of the objective lens based on a displacement signal in the servo step;
An impact detection step of detecting an impact applied from the outside to the optical pickup;
And a control step of switching from the servo operation of the servo step to the brake operation of the brake step only when the impact level detected in the impact detection step exceeds a predetermined value. 4. The optical disc recording / reproducing method according to claim 3, wherein the control step continues the brake step for a predetermined time from the time when the shock level detected in the shock detection step does not exceed a predetermined value. Tracking servo means for detecting a tracking error signal of a focused light beam emitted from an objective lens of an optical head and applied to an optical disk having a groove, and supplying the tracking error signal to a lens actuator for driving the objective lens; and the tracking Brake operation timing signal generating means for generating a brake operation timing signal based on the error signal and the land / groove identification signal of the focused light beam, and brakes the tracking servo means by the brake operation timing signal. In the tracking servo device of the optical disk drive device as described above,
A shock detecting means is provided in the optical head,
A tracking servo apparatus for an optical disk drive apparatus, wherein the supply of the brake operation timing signal to the tracking servo means is controlled in accordance with the level of a shock detection signal from the shock detection means. Tracking servo means for detecting a tracking error signal of a focused light beam emitted from an objective lens of an optical head and applied to an optical disk having a groove, and supplying the tracking error signal to a lens actuator for driving the objective lens; and the tracking Brake operation timing signal generating means for generating a brake operation timing signal based on the error signal and the land / groove identification signal of the focused light beam, and brakes the tracking servo means by the brake operation timing signal. In the tracking servo method of the optical disk drive device as described above,
A tracking servo method for an optical disk drive device, wherein the supply of the brake operation timing signal to the lens actuator is controlled in accordance with a level of a shock detection signal obtained by detecting a shock of the optical head. .

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