JP2012243329A - Optical disk drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk drive capable of determining in which inter-layer a jump fails in the case of continuously performing an inter-layer jump with respect to an optical disk.SOLUTION: The optical disk drive provided with an inter-layer jumping part for executing an inter-layer jump with respect to an optical disk includes a preserving part for preserving a set value corresponding to a recording layer of a jump destination in a storing part each time an inter-layer jump of one time is executed in the case that the inter-layer jumping part continuously executes an inter-layer jump, and a determining part for reading the set value from the storing part and determining an inter-layer where the jump fails on the basis of the read set value when the inter-layer jump fails.

Description

  The present invention relates to an optical disc apparatus that performs an interlayer jump on an optical disc.

  Conventionally, there are optical discs such as a Blu-ray Disc (DVD) and a DVD (Digital Versatile Disc), among which a multi-layer disc having a plurality of recording layers exists.

  In order to record / reproduce data to / from such a multi-layer disc, an interlayer jump that moves the focal position of the objective lens (light beam spot position) of the optical pickup from the current recording layer to the target recording layer is performed. Do. Various optical disc apparatuses that perform such an interlayer jump have been proposed (for example, Patent Document 1).

JP 2009-140573 A

  When the multi-layer disc is a two-layer disc having two recording layers, it is possible to determine which layer has failed even if the jump fails based on the jump direction or the address acquired before the jump.

  However, in recent years, multi-layer discs having three or four recording layers have appeared, and in such multi-layer discs, interlayer jumps may be performed continuously. In such a case, even if an attempt is made to apply the same method as that for the above-mentioned two-layer disc, the jump direction is the same for any interlayer jump, and the tracking servo is turned off during the jump, so the address cannot be acquired. Therefore, there is a problem that it cannot be determined in which layer the jump has failed. Also, if the layers that failed to jump are known, it is possible to reset the parameters related to the failed layer jumps, but such resetting is also impossible because the layers that failed to jump are unknown.

  In view of the above problems, an object of the present invention is to provide an optical disc apparatus capable of determining which layer the jump has failed when performing an interlayer jump on an optical disc continuously.

In order to achieve the above object, the present invention provides an optical disc apparatus including an interlayer jump unit that performs an interlayer jump on an optical disc.
When the interlayer jump is executed continuously by the interlayer jump unit, a storage unit that saves a setting value corresponding to the recording layer of the jump destination in the storage unit every time an interlayer jump is executed,
When an interlayer jump fails, a configuration is provided that includes a determination unit that reads a set value from the storage unit and determines an interlayer that has failed to jump based on the read set value.

  According to such a configuration, it is possible to determine between which layers the jump has failed when performing the interlayer jump on the optical disc continuously.

Further, in the above configuration, the apparatus further includes a change setting unit that changes and sets a parameter for an interlayer jump between layers that have failed in the jump determined by the determination unit,
The interlayer jump unit may be configured to retry consecutive interlayer jumps using the changed and set parameters.

  According to such a configuration, the possibility of succeeding in consecutive interlayer jumps by retry increases.

  In any of the above configurations, a spherical aberration correction unit that corrects spherical aberration in the recording layer may be provided, and the setting value may be a setting value of the spherical aberration correction unit.

  Since the set value of the spherical aberration correction unit varies from recording layer to recording layer, it is suitable for determining an interlayer that has failed to jump.

  The spherical aberration correction unit may be a beam expander, for example.

  According to the present invention, it is possible to determine between which layers the jump has failed when performing the interlayer jump on the optical disc continuously.

1 is a schematic configuration diagram showing an optical disc apparatus according to an embodiment of the present invention. It is the schematic which shows the optical system of the optical pick-up which concerns on one Embodiment of this invention. It is a figure which shows typically the disc structure of a 4-layer Blu-ray disc. It is a flowchart which shows the interlayer jump process as a comparative example with respect to this invention. It is a flowchart which shows the interlayer jump process which concerns on one Embodiment of this invention. It is a flowchart which shows the interlayer jump process which concerns on one Embodiment of this invention.

  An embodiment of the present invention will be described below with reference to the drawings. Here, an optical disk device capable of performing reproduction on a Blu-ray disc having four recording layers will be described as an example.

  FIG. 1 is a schematic configuration diagram showing an optical disc apparatus 100 according to an embodiment of the present invention. The optical disc apparatus 100 includes an optical pickup 1, an RF amplifier 2, a tracking servo filter 3, a focus servo filter 4, an actuator driver 5, a drive pulse generator 6, a stepping motor driver 7, a reproducing unit 8, A control unit 9, a feed motor 10, and a spindle motor 11 are provided. The optical disc apparatus 100 can perform playback on a four-layer BD 50 that is a Blu-ray disc having four recording layers.

  The optical pickup 1 irradiates the four-layer BD 50 with a light beam and reads various information such as audio information and video information recorded on the four-layer BD 50. Details of the inside of the optical pickup 1 will be described later.

  The RF amplifier 2 performs arithmetic processing based on the signal obtained by the photodetector 28 (FIG. 2) included in the optical pickup 1 and generates various signals such as an RF signal, a focus error signal, and a tracking error signal.

  The reproduction unit 8 binarizes the RF signal input from the RF amplifier 2, performs demodulation processing on the binarized signal, generates video / audio data, and decodes the generated video / audio data. Further, the playback unit 8 performs D / A conversion on the decoded video / audio data and outputs the data to a device such as a television connected to the device body.

  The tracking servo filter 3 generates a tracking drive signal by performing a predetermined calculation on the tracking error signal input from the RF amplifier 2 and outputs the tracking drive signal to the actuator driver 5. The actuator driver 5 drives the actuator 29 (FIG. 2) included in the optical pickup 1 based on the tracking drive signal, and moves the objective lens 26 (FIG. 2) included in the optical pickup 1 in the tracking direction (radial direction of the four-layer BD 50). ) To drive control. Thereby, tracking servo for causing the light beam to follow the track of the four-layer BD 50 is performed.

  The focus servo filter 4 generates a focus drive signal by performing a predetermined calculation on the focus error signal input from the RF amplifier 2 and outputs the focus drive signal to the actuator driver 5. The actuator driver 5 drives the actuator 29 (FIG. 2) included in the optical pickup 1 based on the focus drive signal, and moves the objective lens 26 (FIG. 2) included in the optical pickup 1 in the focus direction (recording surface of the four-layer BD50). Drive control in the vertical direction). As a result, focus servo for causing the focal position of the objective lens 26 to follow the recording layer of the four-layer BD 50 is performed.

  The drive pulse generation unit 6 generates a kick pulse signal and a brake pulse signal based on an instruction from the control unit 9 and outputs them to the actuator driver 5. The kick pulse signal is a pulse signal for accelerating the objective lens 26 (FIG. 2) in the direction approaching the target recording layer at the time of interlayer jump. The brake pulse signal is a pulse signal for accelerating the objective lens 26 in the direction opposite to the direction approaching the target recording layer during the interlayer jump. The actuator driver 5 drives the actuator 29 (FIG. 2) based on the kick pulse signal and the brake pulse signal, and drives and controls the objective lens 26 in the focus direction.

  The stepping motor driver 7 drives the stepping motor 30 (FIG. 2) included in the optical pickup 1 based on the stepping motor drive signal from the control unit 9, and the beam expander 24 (FIG. 2) included in the optical pickup 1 is driven. Drive control. Thereby, the spherical aberration in each recording layer can be corrected.

  The control unit 9 is constituted by a microcomputer, for example, and controls each part of the apparatus main body. The control unit 9 includes a ROM 9a for storing a control program and a RAM 9b as a work memory.

  The feed motor 10 drives the optical pickup 1 in the radial direction of the four-layer BD 50 to perform a seek operation. The spindle motor 11 drives the four-layer BD50 in the rotation direction.

  FIG. 2 is a schematic diagram showing an optical system of the optical pickup 1 according to the embodiment of the present invention. The optical pickup 1 irradiates the four-layer BD50 with a light beam and receives reflected light. Thereby, the information recorded on the recording layer of the four-layer BD50 is read.

  The optical pickup 1 includes a light source 20, a collimator lens 21, a beam splitter 22, a rising mirror 23, a beam expander 24, a quarter wavelength plate 25, an objective lens 26, a detection lens 27, a light A detector 28, an actuator 29, and a stepping motor 30 are provided.

  The light source 20 is a laser diode capable of emitting a 405 nm band light beam corresponding to a Blu-ray disc.

  The collimating lens 21 converts the light beam emitted from the light source 20 into parallel light. The light beam converted into parallel light by the collimator lens 21 is sent to the beam splitter 22.

  The beam splitter 22 functions as a light separation element that separates an incident light beam, transmits the light beam transmitted from the collimating lens 21, guides it to the 4-layer BD50 side, and reflects it by the 4-layer BD50. The reflected light is reflected and guided to the photodetector 28 side. The light beam that has passed through the beam splitter 22 is sent to the rising mirror 23.

  The raising mirror 23 reflects the light beam transmitted through the beam splitter 22 and guides it to the four-layer BD 50. The rising mirror 23 is inclined by 45 ° with respect to the optical axis of the light beam from the beam splitter 22, and the optical axis of the light beam reflected by the rising mirror 23 is the recording surface of the four-layer BD50. And almost orthogonal. The light beam reflected by the rising mirror 23 is sent to the beam expander 24.

  The beam expander 24 includes a concave lens and a convex lens, and a stepping motor 30 drives and controls the distance between the concave lens and the convex lens. Thereby, the parallelism of the light beam directed toward the objective lens 26 is adjusted, and the spherical aberration in each recording layer of the four-layer BD 50 is corrected. The light beam that has passed through the beam expander 24 is sent to the quarter-wave plate 25.

  The quarter wavelength plate 25 has a function of converting incident linearly polarized light into circularly polarized light and converting incident circularly polarized light into linearly polarized light. Laser light transmitted from the beam expander 24 and passing through the quarter-wave plate 25 is converted from linearly polarized light to circularly polarized light and sent to the objective lens 26.

  The objective lens 26 condenses the light beam transmitted through the quarter wavelength plate 25 on the recording layer of the four-layer BD50. The objective lens 26 is driven by an actuator 29 in a tracking direction (left-right direction in FIG. 2) and a focus direction (up-down direction in FIG. 2). The actuator 29 may be any actuator that can drive the objective lens 26 with a Lorentz force by passing a driving current through a coil (not shown) positioned in a magnetic field formed by a permanent magnet (not shown), for example.

  The reflected light reflected by the four-layer BD 50 passes through the objective lens 26, the quarter-wave plate 25, and the beam expander 24 in this order, is reflected by the rising mirror 23, is further reflected by the beam splitter 22, The light is condensed by a detection lens 27 onto a light receiving element provided in the light detector 28.

  The photodetector 28 converts light received using a light receiving element such as a photodiode into an electrical signal and outputs the electrical signal to the RF amplifier 2 (FIG. 1). The photodetector 28 includes, for example, a light receiving region divided into four parts, and can individually perform photoelectric conversion for each region and output an electric signal.

  Here, the structure of the four-layer BD50 will be described. FIG. 3 is a diagram schematically showing the disk structure of the four-layer BD50. As shown in FIG. 3, the four-layer BD 50 includes a recording layer L0, an intermediate layer 54, a recording layer L1, an intermediate layer 53, a recording layer L2, an intermediate layer 52, a recording layer L3, and a cover layer 51 on a polycarbonate substrate 55. It has a laminated structure. The light beam emitted from the objective lens 26 (FIG. 2) is incident from the cover layer 51 side and is condensed on one of the recording layers L0 to L3.

  Next, interlayer jump processing by the optical disc apparatus 100 according to an embodiment of the present invention will be described. Here, before explaining the interlayer jump processing according to an embodiment of the present invention, the interlayer jump processing as a comparative example with the present invention will be described first.

  FIG. 4 shows a flowchart regarding interlayer jump processing as a comparative example with the present invention. Here, an example in which an interlayer jump is continuously performed from the recording layer L0 to the recording layer L3 (FIG. 3) of the four-layer BD50 will be described.

  Assume that focus servo is performed so that the focal position of the objective lens 26 follows the recording layer L0 when the processing of FIG. 4 is started. When the processing of FIG. 4 is started, in step S1, the control unit 9 reads the parameters for jumping between the recording layers L0 to L1, recording layers L1 to L2, and recording layers L2 to L3 from the ROM 9a. Is set in the RAM 9b. The jump parameters include a kick pulse signal level, a brake pulse signal level, and the like.

  Next, in step S2, the control unit 9 sets the focus servo filter 4 for the recording layer L1 that is the jump destination in the interlayer jump from the recording layer L0 to L1. The setting here includes setting a focus servo gain value and the like. Further, the control unit 9 sets the tracking servo filter 3 so as to turn off the tracking servo.

  In step S3, the control unit 9 sends a stepping motor drive signal to the stepping motor driver 7 to set the beam expander 24 for the recording layer L1 that is the jump destination.

  In step S4, an interlayer jump is executed. Specifically, the control unit 9 first sets the focus servo filter 4 to turn off the focus servo, and instructs the drive pulse generation unit 6 based on the jump parameters of the recording layers L0 to L1 set in the RAM 9b. The drive pulse generator 6 generates a kick pulse signal and a brake pulse signal. As a result, the objective lens 26 is driven and controlled in the direction from the recording layer L0 to L1. Then, the control unit 9 sets the focus servo filter 4 to turn on the focus servo. Thus, if the control unit 9 can confirm that the focus servo has been pulled in, the jump from the recording layer L0 to L1 will be successful, and if the control unit 9 has confirmed that the focus servo cannot be pulled in, the jump will fail ( N) in step S5, the process proceeds to step S6.

  When the jump from the recording layer L0 to L1 is successful, the control unit 9 sets the focus servo filter 4 for the next jump destination recording layer L2 and also uses the beam expander for the next jump destination recording layer L2. Set 24. Then, the control unit 9 sets the focus servo filter 4 to turn off the focus servo, instructs the drive pulse generation unit 6 based on the jump parameters of the recording layers L1 to L2 set in the RAM 9b, and drives the drive pulse. The generator 6 generates a kick pulse signal and a brake pulse signal. As a result, the objective lens 26 is driven and controlled in the direction from the recording layer L1 to L2. Then, the control unit 9 sets the focus servo filter 4 to turn on the focus servo. Thus, if the control unit 9 can confirm that the focus servo has been pulled in, the jump from the recording layer L1 to L2 will be successful, and if the control unit 9 has confirmed that the focus servo cannot be pulled in, the jump will fail ( N) in step S5, the process proceeds to step S6.

  When the jump from the recording layer L1 to L2 is successful, the interlayer jump from the recording layer L2 to L3 is executed as described above. As a result, if the jump is successful (Y in step S5), the process ends normally. On the other hand, if the jump fails (N in step S5), the process proceeds to step S6.

  In step S6, the control unit 9 determines whether or not the number of jump failures is within p (for example, p = 2). If it is within p times (Y in step S6), the process proceeds to step S7, and the focus servo of the objective lens 26 is started so as to follow the recording layer L0 under the control of the control unit 9. Then, the process returns to step S2 to retry the interlayer jump.

  As a result of the retry, if the number of jump failures exceeds p (N in step S6), the process ends in an error.

  In the process of FIG. 4, when the first jump fails, the retry is performed with the same jump parameters as the first time. Therefore, even if the retry is performed p times, there is a high possibility that the jump will fail and end in error. In addition, if the jump fails, it may be possible to retry by changing the jump parameter between each layer, but in that case, there is a high possibility of failure between the layers that have succeeded. Even if it goes, it is highly likely that the jump will fail and end in error.

  Therefore, in order to improve the processing of FIG. 4 as described above, an interlayer jump processing according to an embodiment of the present invention shown in the flowcharts of FIGS. 5A and 5B is proposed. In FIGS. 5A and 5B, the same processing as in FIG. 4 will be described in a simplified manner.

  Assume that focus servo is performed so that the focal position of the objective lens 26 follows the recording layer L0 when the processing of FIG. 5A is started. When the processing of FIG. 5A is started, in step S11, the control unit 9 reads jump parameters of the recording layers L0 to L1, recording layers L1 to L2, and recording layers L2 to L3 from the ROM 9a and sets them in the RAM 9b.

  Next, in step S12, the control unit 9 sets the focus servo filter 4 for the recording layer L1 that is the jump destination in the interlayer jump from the recording layer L0 to L1. Further, the control unit 9 sets the tracking servo filter 3 so as to turn off the tracking servo.

  In step S13, the control unit 9 sends a stepping motor drive signal to the stepping motor driver 7 to set the beam expander 24 for the recording layer L1 that is the jump destination. Further, the control unit 9 stores the set value of the beam expander 24 at that time in a predetermined area of the RAM 9b.

  Next, in step S14, an interlayer jump is executed. Here, the processing is basically the same as that in step S4 described in FIG. 4, but the control unit 9 sets the beam expander 24 every time the interlayer jump is successful, and the set value at that time is stored in the RAM 9b. Save in the predetermined area (overwrite).

  If successive interlayer jumps succeed in step S14 (Y in step S15), the process ends normally, but if the interlayer jump fails midway (N in step S15), the process proceeds to step S16.

  In step S16, the control unit 9 determines whether or not the number of jump failures is within n times (for example, n = 1). If n times or less (Y in step S16), the process proceeds to step S17, and the focus servo of the objective lens 26 is started so as to follow the recording layer L0 under the control of the control unit 9. Then, the process returns to step S12 to retry the interlayer jump.

  As a result of the retry, if the number of jump failures exceeds n (N in Step S16), the process proceeds to Step S18 in FIG. 5B. In step S18, the control unit 9 reads the set value of the beam expander 24 stored in the predetermined area of the RAM 9b. Then, based on the read set value, the control unit 9 determines the layer that failed to jump (for example, if the read set value of the beam expander 24 is for the recording layer L2, the layer between the recording layers L1 and L2). Judged that the jump failed.

  Next, in step S19, the control unit 9 changes and sets jump parameters between layers that have failed to jump.

  In step S20, the controller 9 determines whether or not the number of jump failures is within p (p> n, for example, p = 2). If it is within p times (Y in step S20), the process proceeds to step S21, and the focus servo of the objective lens 26 is started by the control by the control unit 9 so that the focal position of the objective lens 26 follows the recording layer L0. Then, processing from step S22 to step S25 is performed (processing similar to that from step S2 to step S5 in FIG. 4).

  If successive interlayer jumps succeed in step S25 (Y in step S25), the process ends normally, but if the interlayer jump fails midway (N in step S25), the process returns to step S20. In step S20, if the number of jump failures exceeds p times (N in step S20), an error ends, and if it is within p times (Y in step S20), the process proceeds to step S21 and a retry is performed.

  According to such an interlayer jump process according to the present embodiment, it is possible to determine the interlayer that has failed to jump by reading the stored setting value of the beam expander 24, and to change and set the jump parameter between the layers. Therefore, the possibility of succeeding in successive interlayer jumps by retrying within p times is increased, which is superior to the comparative example described in FIG.

  Note that instead of the setting value of the beam expander 24, for example, a focus gain value may be stored, and the focus gain may be read to determine an interlayer where the jump has failed. However, the focus gain value may be the same value depending on the recording layer, and in this case, it is not possible to determine the layer where the jump has failed, so it is preferable to use the setting value of the beam expander 24 that is different for each recording layer. Become.

  Although one embodiment of the present invention has been described above, the embodiment can be variously modified within the scope of the gist of the present invention.

  For example, in the above-described embodiment, the beam expander is used as the spherical aberration correction unit. However, spherical aberration correction may be performed using a liquid crystal element or the like.

  In the above embodiment, a four-layer BD is described as an example of an optical disk, but the present invention is applicable to an optical disk having three or more recording layers.

  In the above embodiment, an apparatus for reproducing an optical disc has been described as an example. However, any apparatus that performs at least one of reproduction and recording may be used.

DESCRIPTION OF SYMBOLS 100 Optical disk apparatus 1 Optical pick-up 2 RF amplifier 3 Tracking servo filter 4 Focus servo filter 5 Actuator driver 6 Drive pulse generation part 7 Stepping motor driver 8 Playback part 9 Control part 9a ROM
9b RAM
DESCRIPTION OF SYMBOLS 10 Feed motor 11 Spindle motor 20 Light source 21 Collimating lens 22 Beam splitter 23 Rising mirror 24 Beam expander 25 1/4 wavelength plate 26 Objective lens 27 Detection lens 28 Photo detector 29 Actuator 30 Stepping motor 50 4 layer BD (Blu-ray disc) )
51 Cover layer 52, 53, 54 Intermediate layer 55 Polycarbonate substrate

Claims (4)

In an optical disc apparatus having an interlayer jump unit for performing an interlayer jump on an optical disc,
When the interlayer jump is executed continuously by the interlayer jump unit, a storage unit that saves a setting value corresponding to the recording layer of the jump destination in the storage unit every time an interlayer jump is executed,
An optical disc apparatus comprising: a determination unit that reads a set value from the storage unit when an interlayer jump fails and determines an interlayer that has failed to jump based on the read set value. A change setting unit for changing and setting a parameter for an interlayer jump between layers that failed the jump determined by the determination unit;
2. The optical disc apparatus according to claim 1, wherein the interlayer jump unit retries successive interlayer jumps using the changed and set parameters.   The optical disk apparatus according to claim 1, further comprising a spherical aberration correction unit that corrects spherical aberration in the recording layer, wherein the setting value is a setting value of the spherical aberration correction unit.   The optical disk apparatus according to claim 3, wherein the spherical aberration correction unit is a beam expander.

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