JP6008809B2 - Optical disk device - Google Patents

Description

  The present invention relates to an optical disc apparatus that servo-controls tracking of an optical pickup with respect to an optical disc.

  2. Description of the Related Art Conventionally, in an optical disk apparatus that performs reproduction or recording of an optical disk, a lens shift generation allowable range of an objective lens of an optical pickup is set, and an amount of movement of the objective lens in the disk radial direction during tracking (that is, a lens shift amount) When the lens shift exceeds the lens shift occurrence allowable range, the feed motor is driven to control the optical pickup to be fed in the disk radial direction.

  However, tracking is maintained with an optical pickup in which the movable range of the objective lens in the disk radial direction is narrower than the allowable range of lens shift, or an optical pickup in which the movable range of the objective lens in the disk radial direction is biased toward the inner or outer peripheral side of the disk. There was a problem that tracking servo was lost.

  As a method for avoiding tracking servo deviation, for example, in the optical disc apparatus according to Patent Document 1, the lens shift amount with respect to the neutral position of the objective lens in the actuator of the optical pickup is measured before the optical pickup is sent to the recording start address. Thereby, the lens shift amount with respect to the neutral position of the objective lens in the actuator immediately after the start of recording can be predicted. Therefore, the lens shift amount immediately after the start of recording can be managed within a certain range, and the tracking servo deviation immediately after the start of recording that occurs when the lens shift amount with respect to the actuator is too large can be avoided.

JP 2007-87545 A

In the optical disk device of Patent Document 1, when there is a deviation between the movable range of the objective lens and the allowable range for generating the lens shift, even if the tracking servo deviation immediately after the start of recording, which occurs because the lens shift amount with respect to the actuator is too large, During the subsequent operation, tracking servo discontinuity occurs continuously. Further, since it is necessary to measure the lens shift amount by moving the objective lens to the lens shift amount measurement address, it is not possible to cope with tracking servo deviation occurring during the recording or reproducing operation.
In other words, the optical disk device of Patent Document 1 has a problem that it is difficult to suppress tracking servo deviation during recording or reproducing operation.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an optical disc apparatus that suppresses tracking servo deviation during a recording or reproducing operation.

  An optical disc apparatus according to the present invention has an objective lens for condensing laser light on an optical disc and an actuator for moving the objective lens in the radial direction of the optical disc to shift the lens, and receives the laser light reflected by the optical disc and receives a signal. An optical pickup that outputs, a servo control unit that controls the tracking servo of the objective lens by controlling the actuator based on the output signal of the optical pickup, and a tracking servo deviation that detects tracking servo deviation based on the output signal of the optical pickup A lens shift amount for detecting the lens shift amount of the objective lens based on the output signal of the detection unit and the optical pickup, and determining whether the lens shift amount exceeds a lens shift generation allowable range set in the radial direction of the optical disc Detection part and tracking servo deviation detection If part detects a tracking servo off, in which and a lens shift tolerance value adjustment unit for adjusting shifting the lens shift occurs tolerance on the inner circumferential side or outer circumferential side of the disk radial direction.

  According to the present invention, when the tracking servo deviation is detected, the lens shift occurrence allowable range is adjusted to be shifted to the inner or outer peripheral side in the radial direction of the optical disc, so that the objective lens can be moved during the recording or reproducing operation. It is possible to provide an optical disc apparatus that can adjust the allowable range of lens shift generation according to the range and suppress the tracking servo deviation during the recording or reproducing operation.

1 is a block diagram showing a configuration of an optical disc device according to Embodiment 1 of the present invention. It is a flowchart which shows the adjustment operation | movement by a lens shift allowable value adjustment part. It is a figure explaining the adjustment method of the lens shift generation | occurrence | production tolerance range and lens shift generation | occurrence | production allowable amount by a lens shift allowable value adjustment part.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of the optical disc apparatus according to the first embodiment. In FIG. 1, only the main part according to the present invention is shown, and other known components of the optical disk apparatus are not shown. The optical disc apparatus is composed of an optical pickup module 1, a signal generation unit 2, and a motor driver unit 3, and performs at least one of reproduction and recording operations on the optical disc 4.

  The optical pickup module 1 includes a spindle motor 101, an optical pickup feed motor 102, a guide shaft 103, a feed unit 104, an actuator 105, and an objective lens 106. The signal generation unit 2 includes a signal generation matrix amplifier 201, a tracking servo deviation detection unit 202, a servo control unit 203, a lens shift amount detection unit 204, and a lens shift allowable value adjustment unit 205.

  The spindle motor 101 rotates the optical disc 4. The objective lens 106 condenses laser light emitted from a light source (not shown) on the recording surface of the optical disc 4 and performs at least one of information reproduction and recording. The laser light reflected by the optical disk 4 is detected by a split sensor (not shown) installed inside the actuator 105 and output to the signal generation matrix amplifier 201. The actuator 105 moves the objective lens 106 in the radial direction A of the optical disc 4 and shifts the lens. The objective lens 106, actuator 105, light source, split sensor, and the like constitute an optical pickup PU.

  The feed unit 104 includes an optical pickup feed motor 102, a guide shaft 103, a gear (not shown), a screw shaft, and the like. In a state where the optical pickup PU is supported by the guide shaft 103, the optical pickup feed motor 102 rotates the screw shaft and converts the rotational motion into a linear motion, thereby moving the optical pickup PU in the radial direction A.

  The signal generation unit 2 is configured by, for example, a CPU (Central Processing Unit), and by executing a program, the signal generation matrix amplifier 201, the tracking servo deviation detection unit 202, the servo control unit 203, the lens shift amount detection unit 204, and the lens A function as the shift allowable value adjustment unit 205 is realized.

  The signal generation matrix amplifier 201 amplifies the signal detected by the split sensor inside the optical pickup PU, and a tracking error signal (hereinafter referred to as TE signal), a lens shift signal indicating the lens shift amount of the objective lens 106 in the actuator 105, etc. A control signal for servo-controlling the optical pickup feed motor 102 and the actuator 105 is generated.

  Based on the lens shift signal, the lens shift amount detection unit 204 detects a signal including the lens shift amount with respect to the neutral position of the objective lens 106 in the actuator 105 during the recording or reproducing operation, and the lens shift amount is within the lens shift generation allowable range. If it exceeds (details will be described later), the actuator 105 follows the objective lens 106, and servo control is performed so as to output a drive signal for the optical pickup feed motor 102 that deserves a lens shift generation allowable amount (details will be described later). Notification to the unit 203.

The servo control unit 203 is an actuator so that the laser light of the optical pickup PU follows the track of the optical disc 4 based on the control signal such as the TE signal generated by the signal generation matrix amplifier 201 and the notification of the lens shift amount detection unit 204. By outputting a drive signal for controlling 105 and the optical pickup feed motor 102, feedback control of the optical disc apparatus is realized. Since feedback control may be performed using a known technique, detailed description thereof is omitted.
The motor driver unit 3 drives the optical pickup feed motor 102 and the actuator 105 in accordance with the drive signal output from the servo control unit 203.

  Thereby, during the recording or reproducing operation of the optical disc apparatus, the actuator 105 moves the objective lens 106 in the radial direction A to cause the laser beam to follow the track of the optical disc 4, and when the lens shift amount exceeds the allowable range for generating the lens shift, The feed unit 104 sends the optical pickup PU in the radial direction A, causing the actuator 105 to follow the objective lens 106.

However, tracking cannot be maintained with the optical pickup PU in which the movable range of the objective lens 106 is narrower than the allowable range of occurrence of lens shift, or the optical pickup PU in which the movable range of the objective lens 106 is biased toward the inner or outer peripheral side of the optical disc 4. There was a problem that tracking servo was lost.
Therefore, in the first embodiment, when the tracking servo deviation is detected during the recording or reproducing operation, the lens shift generation allowable range or the lens shift generation allowable amount is adjusted according to the actual movable range of the objective lens 106. Suppress tracking servo disengagement.

  Based on the TE signal, the tracking servo deviation detection unit 202 detects the tracking servo deviation that occurs during the reproduction or recording operation, and when the tracking servo deviation is detected, sets the lens shift generation allowable range or the lens shift generation allowable amount. The lens shift allowable value adjustment unit 205 is notified so as to adjust.

  The lens shift allowable value adjustment unit 205 adjusts one or both of the lens shift generation allowable range and the lens shift generation allowable amount when the tracking servo deviation is detected, and the lens shift generation allowable after the adjustment is adjusted. The range is notified to the lens shift amount detection unit 204. The lens shift amount detection unit 204 compares the lens shift generation allowable range notified from the lens shift allowable value adjustment unit 205 with the lens shift amount, and when the lens shift amount exceeds the lens shift generation allowable range, the servo control unit 203. An instruction to send the optical pickup PU to is issued.

FIG. 2 is a flowchart showing the operation of the lens shift allowable value adjustment unit 205.
The lens shift allowable value adjusting unit 205 sets the lens shift generation allowable amount to K [μm] after the optical disc apparatus is powered on (step ST1), and the lens shift generation allowable range Kin = K / in the inner peripheral direction of the optical disc 4. 2 [μm], the lens shift generation allowable range in the outer peripheral direction Kout = K / 2 [μm] is set (step ST2). Further, the minimum lens shift generation allowable range is set to L [μm] (step ST2).
The initial values of K and L are values given to the lens shift allowable value adjustment unit 205 in advance. The minimum lens shift generation allowable range L is the minimum value of either one of the lens shift generation allowable ranges in the inner and outer peripheral directions in the radial direction A of the optical disc 4.

  Subsequently, the lens shift allowable value adjustment unit 205 notifies the lens shift amount detection unit 204 of the set lens shift occurrence allowable ranges Kin and Kout in the inner and outer peripheral directions.

Further, the lens shift allowable value adjustment unit 205 sets the number of adjustments P for the lens shift generation allowable range P = 0, the number of adjustments Q for the lens shift generation allowable amount Q = 2, and the maximum number of adjustments R for the lens shift generation allowable amount R = 5. (Step ST3).
The initial values of P, Q, and R are values given to the lens shift allowable value adjustment unit 205 in advance. Note that P is 0 and Q is 2, but R may be any number of times.

  The tracking servo deviation detection unit 202 monitors the occurrence of tracking servo deviation when recording or reproduction is started and during operation, and notifies the lens shift allowable value adjustment unit 205 when the tracking servo deviation occurs. When receiving the notification of occurrence of tracking servo deviation (step ST4), the lens shift allowable value adjustment unit 205 performs the processing of steps ST5 to ST14 to adjust the lens shift generation allowable range and the lens shift generation allowable amount.

  The lens shift allowable value adjustment unit 205 compares the adjustment number P of the lens shift generation allowable range with the adjustment number Q of the lens shift generation allowable amount, and the adjustment number P of the lens shift generation allowable range is the number of adjustments of the lens shift generation allowable amount. If it is smaller than Q (step ST5 “YES”), the lens shift allowable range is adjusted (steps ST6 to ST9). If larger (step ST5 “NO”), the lens shift generation allowable amount is adjusted. (Steps ST11 to ST14).

First, a method for adjusting the lens shift occurrence allowable range will be described.
FIG. 3 is a diagram for explaining a method of adjusting the lens shift generation allowable range and the lens shift generation allowable amount. In the optical pickup PU, the actuator 105 moves the objective lens 106 in the radial direction A of the optical disk 4. Further, in steps ST1 and ST2, as shown in FIG. 3A, the lens shift generation allowable amount K = 200, the lens shift generation allowable ranges Kin and Kout = 100 in the inner and outer peripheral directions, and the minimum lens shift generation allowable range L = 30. Is set.
In this state, the lens shift allowable value adjustment unit 205 compares the lens shift generation allowable range Kout in the outer peripheral direction with the minimum lens shift generation allowable range L (step ST6).

  When the outer lens shift generation allowable range Kout is larger than the minimum lens shift generation allowable range L (“YES” in step ST6), the lens shift allowable value adjustment unit 205 sets L [μm to the outer lens shift generation allowable range Kout. ] And KL [μm] is set to the lens shift generation allowable range Kin in the inner circumferential direction (step ST7). By this adjustment, the state shown in FIG. 3 (a) is changed to FIG. 3 (b).

  On the other hand, when the lens shift generation allowable range Kout in the outer peripheral direction is not larger than the minimum lens shift generation allowable range L (step ST6 “NO”), the lens shift allowable value adjustment unit 205 sets the lens shift generation allowable range Kout in the outer peripheral direction. KL [μm] is set, and L [μm] is set to the lens shift generation allowable range Kin in the inner circumferential direction (step ST8). By this adjustment, the state is changed from FIG. 3A to FIG. 3C.

  Then, after adjusting the lens shift generation allowable range, the lens shift allowable value adjustment unit 205 sets P + 1 [times] as the number of adjustments P of the lens shift generation allowable range (step ST9). Further, the lens shift allowable value adjustment unit 205 notifies the lens shift amount detection unit 204 of the adjusted lens shift generation allowable ranges Kin and Kout in the inner and outer peripheral directions.

  In the state of FIG. 3B or FIG. 3C, if the occurrence of tracking servo deviation is not detected by the tracking servo deviation detection unit 202 (step ST10 “YES”), the lens shift allowable value adjustment unit 205 performs the adjustment process. Exit.

  When the tracking servo deviation does not occur due to the adjustment from the state shown in FIG. 3A to the state shown in FIG. 3B, the movement range of the objective lens 106 is biased toward the inner peripheral direction of the optical disc 4 due to the tracking servo deviation. This is thought to be the cause. Accordingly, the adjustment of shifting the lens shift generation allowable range (Kin + Kout) in the inner circumferential direction in accordance with the deviation is suppressed, thereby preventing the occurrence of tracking servo deviation.

  On the other hand, when the tracking servo deviation does not occur due to the adjustment from the state shown in FIG. 3A to the state shown in FIG. 3C, the movable range of the objective lens 106 is biased toward the outer peripheral direction of the optical disk 4. This is thought to be the cause. Therefore, the adjustment of shifting the lens shift generation allowable range (Kin + Kout) in the outer peripheral direction in accordance with the deviation is suppressed, so that occurrence of tracking servo deviation is suppressed.

  Adjustment of the lens shift generation allowable range (Kin + Kout) may be performed from the inner peripheral side or from the outer peripheral side. If the occurrence of tracking servo misalignment is still detected (step ST10 “NO”) even after adjustment to shift the lens shift generation allowable range (Kin + Kout) to both the inner and outer circumferences is completed (step ST10 “NO”), the number of adjustments of the lens shift generation allowable range Since P becomes equal to the number Q of adjustments for the allowable amount of occurrence of lens shift (step ST5 “NO”), the allowable lens shift adjustment unit 205 subsequently adjusts the allowable amount of occurrence of lens shift.

Next, a method for adjusting the lens shift generation allowable amount will be described.
The allowable lens shift generation amount can be adjusted from the maximum K [μm] to the minimum L × 2 [μm], and is decreased by (K−L × 2) / R [μm] every adjustment of the allowable lens shift generation amount. That is, the adjustment amount for one time is (K−L × 2) / R.
However, the maximum number of adjustments of the lens shift generation allowable amount is R [times], and the adjustment is finished when the number of adjustments Q of the lens shift generation allowable amount exceeds R × 2. This R is set to a value at which the lens shift generation allowable amount K when the lens shift generation allowable amount is adjusted R times is larger than L × 2.

First, the allowable lens shift value adjustment unit 205 compares the number Q of adjustments of the allowable lens shift generation amount with a value obtained by doubling the maximum adjustment frequency R of the allowable lens shift generation amount (step ST11).
When the lens shift occurrence allowable amount adjustment count Q is not smaller than the lens shift occurrence allowable amount maximum adjustment count R × 2 (step ST11 “NO”), the lens shift allowable value adjustment unit 205 performs no adjustment and performs processing. finish.

  On the other hand, when the number Q of adjustments for the allowable amount of lens shift is smaller than the maximum number of adjustments R × 2 for the allowable amount of occurrence of lens shift (step ST11 “YES”), the allowable lens shift adjustment unit 205 The capacity K is narrowed by one adjustment amount and set to K− (KL−2) / R [μm] (step ST12). Further, the lens shift allowable value adjustment unit 205 divides the adjusted lens shift generation allowable amount K into two equal parts, the inner peripheral lens shift generation allowable range Kin = K / 2 [μm], and the outer peripheral lens. The allowable shift generation range Kout = K / 2 [μm] is set (step ST13). By this adjustment, the lens shift generation allowable amount K becomes the state of FIG.

  Then, after adjusting the lens shift generation allowable amount, the lens shift allowable value adjustment unit 205 sets Q + 2 [times] as the number Q of adjustments of the lens shift generation allowable amount (step ST14). Further, the lens shift allowable value adjustment unit 205 notifies the lens shift amount detection unit 204 of the adjusted lens shift generation allowable ranges Kin and Kout in the inner and outer peripheral directions.

  In the state shown in FIG. 3D, if the occurrence of tracking servo deviation is not detected by the tracking servo deviation detection unit 202 (step ST10 “YES”), the lens shift allowable value adjustment unit 205 ends the adjustment process.

  When any of the states of FIGS. 3A to 3C is adjusted to the state of FIG. 3D and tracking servo detachment does not occur, the tracking servo detachment is the movable range of the objective lens 106. Is considered to be narrower than the initial setting value of the allowable lens shift generation amount K. Therefore, by adjusting the lens shift generation allowable amount K to be narrowed, the adjusted lens shift generation allowable amount K is within the movable range of the objective lens 106, and the occurrence of tracking servo deviation is suppressed.

When the adjustment of the lens shift generation allowable amount K is performed once, the number of adjustments of the lens shift generation allowable range increases to P + 2 [times], so that the lens shift generation allowable range can be adjusted again (step ST5 " YES ”).
For this reason, when the occurrence of tracking servo deviation is still detected after the adjustment of the lens shift generation allowable amount K is completed (step ST10 “NO”), the lens shift generation allowable amount K is narrowed and the steps after step ST5 are performed. The lens shift generation allowable ranges Kin and Kout are adjusted. Thus, the lens shift allowable value adjusting unit 205 repeats the adjustment of the lens shift generation allowable ranges Kin and Kout and the lens shift generation allowable amount K until the occurrence of tracking servo deviation is eliminated.

  As described above, according to the first embodiment, the optical disc apparatus has the objective lens 106 that condenses the laser light on the optical disc 4 and the actuator 105 that moves the objective lens 106 in the radial direction A of the optical disc 4 and shifts the lens. The optical pickup PU that receives the laser beam reflected by the optical disk 4 and outputs a signal, and the servo control unit 203 that controls the actuator 105 based on the output signal of the optical pickup PU and performs tracking servo control of the objective lens 106. A tracking servo deviation detecting unit 202 for detecting tracking servo deviation based on the output signal of the optical pickup PU, and detecting the lens shift amount of the objective lens 106 based on the output signal of the optical pickup PU. Set in the radial direction A of the optical disk 4 When the lens shift amount detection unit 204 that determines whether or not the lens shift generation allowable range is exceeded and the tracking servo out detection unit 202 detect tracking servo out, the lens shift generation allowable range is set to the inner circumference of the optical disc 4 in the radial direction A. And a lens shift allowable value adjustment unit 205 that performs adjustment to shift to the outer side or the outer peripheral side. For this reason, the lens shift generation allowable range can be adjusted in accordance with the movable range of the objective lens 106 biased toward the inner peripheral side or the outer peripheral side in the radial direction A of the optical disc 4, and tracking servo deviation during recording or reproduction operation can be adjusted. Can be suppressed. As a result, the tracking servo pull-in performance can be improved, and the occurrence of disc recording / playback problems due to tracking servo loss can be avoided.

  Further, according to the first embodiment, the lens shift allowable value adjustment unit 205 narrows the lens shift generation allowable range when the tracking servo out detection unit 202 detects the tracking servo out (ie, the lens shift generation allowable amount is reduced). It was configured to make adjustments. For this reason, with respect to the optical pickup PU in which the movable range of the objective lens 106 is narrow, the lens shift generation allowable amount can be adjusted according to the movable range, and the tracking servo deviation during the recording or reproducing operation can be suppressed.

  Further, according to the first embodiment, the lens shift allowable value adjusting unit 205 sets the lens shift occurrence allowable range to the inner circumference in the radial direction A of the optical disc 4 until the tracking servo deviation detecting unit 202 does not detect the tracking servo deviation. The adjustment to shift to the side or the outer peripheral side and the adjustment to narrow the allowable range for generating the lens shift (that is, to decrease the allowable amount for generating the lens shift) are alternately performed. For this reason, the lens shift generation allowable range and the lens shift generation allowable amount can be adjusted in accordance with the movable range of the objective lens 106, and the tracking servo deviation during the recording or reproducing operation can be suppressed.

  In the present invention, any constituent element of the embodiment can be modified or any constituent element of the embodiment can be omitted within the scope of the invention.

  DESCRIPTION OF SYMBOLS 1 Optical pick-up module, 2 Signal generation part, 3 Motor driver part, 4 Optical disk, 101 Spindle motor, 102 Optical pick-up feed motor, 103 Guide shaft, 104 Feed part, 105 Actuator, 106 Objective lens, 201 Signal generation matrix amplifier, 202 Tracking servo deviation detection unit, 203 servo control unit, 204 lens shift amount detection unit, 205 lens shift allowable value adjustment unit, PU optical pickup, A optical disk radial direction, K lens shift generation allowable amount, Kin lens shift in inner circumference direction Allowable generation range, Kout Permissible lens shift generation range in the outer peripheral direction, L Minimum lens shift generation allowable range, P Lens shift generation allowable range adjustment count, Q Lens shift generation allowable adjustment count, R Lens system Maximum number of adjustments of preparative generation capacity.

Claims (3)

In an optical disc apparatus that records or reproduces information by irradiating an optical disc with a laser beam,
Light that receives the laser light reflected by the optical disk and outputs a signal, having an objective lens that focuses the laser light on the optical disk, and an actuator that moves the objective lens in the radial direction of the optical disk and shifts the lens With a pickup,
A servo control unit for controlling the actuator based on an output signal of the optical pickup and performing tracking servo control of the objective lens;
A tracking servo deviation detecting unit for detecting tracking servo deviation based on an output signal of the optical pickup;
Lens shift amount detection that detects the lens shift amount of the objective lens based on the output signal of the optical pickup and determines whether or not the lens shift amount exceeds a lens shift generation allowable range set in the radial direction of the optical disc And
A lens shift allowable value adjusting unit configured to adjust the lens shift generation allowable range to an inner peripheral side or an outer peripheral side in the radial direction of the optical disc when the tracking servo out detection unit detects tracking servo out. An optical disk device.   2. The optical disk apparatus according to claim 1, wherein the lens shift allowable value adjustment unit performs an adjustment to narrow the lens shift generation allowable range when the tracking servo deviation detection unit detects a tracking servo deviation.   The lens shift allowable value adjustment unit adjusts the lens shift generation allowable range to be shifted to the inner or outer peripheral side in the radial direction of the optical disc until the tracking servo out detection unit no longer detects tracking servo out, and the lens 3. The optical disk apparatus according to claim 2, wherein the adjustment for narrowing the allowable shift generation range is alternately repeated.

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