JP4437791B2 - OPTICAL PICKUP CONTROL DEVICE, ITS PROGRAM AND RECORDING MEDIUM, OPTICAL DISK DEVICE, AND OPTICAL PICKUP CONTROL METHOD - Google Patents

Description

  The present invention relates to an optical pickup control device used for recording or reproduction of an optical disc having a plurality of recording layers, a program and recording medium thereof, an optical disc device, and an optical pickup control method.

  2. Description of the Related Art Conventionally, an optical disk whose recording capacity is increased by increasing the density formed by stacking a plurality of information recording layers has been widely used as a large capacity optical disk.

  When a signal is recorded on an optical disc having a plurality of recording layers, or when information on the optical disc is recorded / reproduced, the light emitted from the optical system is accompanied by an interlayer jump that moves the recording / reproducing layer. Must be focused on each layer.

  That is, in an optical disc apparatus that performs recording / reproduction of an optical disc, a focus jump is performed to move the focal position from one information recording layer to the other information recording layer in accordance with the interlayer jump.

  The spherical aberration that occurs when the substrate thickness of the optical disk is different from a predetermined amount has a characteristic that is proportional to the fourth power of the numerical aperture (NA). In general, N.I. A. In a high-density optical disk apparatus that uses a large objective lens, it is essential to correct spherical aberration between the layers of a multilayer disk having a plurality of information recording layers having different substrate thicknesses.

  More specifically, first, when a focus jump is performed from one information recording layer to the other information recording layer, spherical aberration is caused due to a difference in layer thickness between the two information recording layers.

  While the irradiation light is focused on one information recording layer (first recording layer) by the focus control, the correction amount of the spherical aberration is in an optimum state with respect to the first recording layer. However, if the irradiation information is focused on the other information recording layer (second recording layer) without changing the correction state of the spherical aberration optimized for the first recording layer, the first recording is performed. Due to the spherical aberration between the layer and the second recording layer, the correction amount of the spherical aberration is not optimal in the second recording layer.

  If the correction amount of the spherical aberration in the second recording layer is not optimal, when focus jump is performed, focus control for the second signal recording layer becomes unstable, and the focus jump fails.

  Therefore, in order to enable a stable focus jump, the spherical aberration correction amount is changed to a correction amount suitable for the first recording layer before the focus of the irradiation light is moved from the first recording layer to the second recording layer. Therefore, it is necessary to convert to a correction amount suitable for the second recording layer.

  However, conventionally, focus pull-in (start of the operation of the focus follower) is performed on the recording layer for recording or reproduction, and subsequently operations such as acquisition of control information such as focus servo, tracking servo, and address are performed. Is called. Thereafter, the spherical aberration is corrected so that the address signal or the reproduction signal becomes the best, and recording or reproduction is executed. Therefore, when the correction amount of the spherical aberration is far from the value suitable for the recording layer for recording or reproducing, the focus jump fails for the reason described above.

Patent Document 1 discloses a focusing control device for an optical pickup that makes it possible to perform a stable focus jump by devising a procedure for correcting a focus jump and spherical aberration. In other words, in this optical pickup focusing control device, when a focus jump from one recording layer to another recording layer is completed, the focus jump is started after the correction of spherical aberration for the other recording layer is completed.
JP 2003-77142 A (published March 14, 2003)

  However, in the above conventional optical pickup focusing control device, although the possibility of focus pull-in is reduced and the possibility of focus jump failure is reduced, the focus jump cannot be started until spherical aberration correction is completed. .

  That is, in the focusing control device for an optical pickup disclosed in Patent Document 1, the focus jump is started after the spherical aberration correction of the focus jump destination layer is completed. After the focus jump is completed, it is necessary to cause the focus of the irradiation light to follow the track in which data is written by the focus servo. Therefore, there is a problem that it takes an extra time to wait for the completion of spherical aberration correction before starting the focus jump.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to make it possible to shorten the time required to start a focus jump in the process of an interlayer jump.

  In order to solve the above problems, an optical pickup control device of the present invention includes a condensing optical system that condenses irradiation light from a light source on an optical disc having a plurality of recording layers, and Spherical aberration for detecting spherical aberration generated in the condensing optical system as a spherical aberration signal in a control apparatus for an optical pickup including a focal position changing unit that changes a focal position of the irradiation light by moving an objective lens In accordance with the value of the spherical aberration signal, detection means, focus jump driving means for instructing the focus position changing means to drive so as to perform a focus jump that moves the focus position between recording layers of the optical disc, And an operation control means for operating and controlling the focus jump driving means.

  The focus jump is an operation in the process of an interlayer jump that is an operation of moving a recording layer for recording or reproduction on the optical disc. The focus jump is performed by moving the objective lens of the condensing optical system by the focal position changing means, thereby changing the focal position of the light irradiated from the condensing optical system from one recording layer to the other recording layer. The movement is shown.

  According to the above invention, the operation control means can operate the focus jump driving means according to the spherical aberration signal while detecting the spherical aberration as the spherical aberration signal. Therefore, the operation control means can flexibly determine the timing for operating the focus jump drive means according to the value of the spherical aberration signal while monitoring the changing spherical aberration signal.

  That is, when the focus jump driving means is operated in accordance with a preset spherical aberration correction value, the spherical aberration correction is completed for the recording layer to which the focus jump is made so that the focus jump does not fail. A correction value must be set. However, when operating the focus jump driving means according to the spherical aberration signal, the operation control means at the time when the value of the spherical aberration signal at the time when the focus jump does not fail is shown while monitoring the spherical aberration signal. It becomes possible to operate the focus jump driving means. Therefore, it is possible to operate the focus jump driving means at a timing at which the focus jump is possible even if the correction of the spherical aberration is not completed with respect to the recording layer of the focus jump destination.

  Accordingly, it is possible to start the operation of the focus jump driving means earlier than the operation of the focus jump driving means after waiting for the correction of the spherical aberration to be completed. As a result, it is possible to shorten the time required to start the focus jump during the interlayer jump process.

  By the way, the control device for the optical pickup may be realized by hardware, or may be realized by causing a computer to execute a program. Specifically, the program according to the present invention is a program that causes a computer to operate as an operation control unit, and the program is recorded on a recording medium according to the present invention.

  When these programs are executed by a computer, the computer operates as a control device for the optical pickup. Therefore, similarly to the control device for the optical pickup, it is possible to shorten the time required to start the focus jump.

  In the control apparatus for an optical pickup according to the present invention, based on the correction signal acquired by the correction signal acquiring means for acquiring the correction signal for correcting the spherical aberration signal from the reflected light of the optical disc, and the correction signal acquired by the correction signal acquiring means. A spherical aberration signal correcting means for correcting the spherical aberration signal, and the operation control means controls the focus jump driving means according to the value of the spherical aberration signal corrected by the spherical aberration signal correcting means. It is preferable to do.

  Since there is an error in the thickness of the cover layer for each optical disc, the spherical aberration signal detected for each optical disc is generally different. Since the spherical aberration signal is obtained from a part of the reflected light from the optical disk surface, the value of the spherical aberration signal is proportional to the value of the correction signal from the reflected light from the optical disk.

  Thereby, the spherical aberration signal is corrected by the spherical aberration signal correction means according to the signal from the reflected light of each of the plurality of optical disks acquired by the correction signal acquisition means, thereby correcting the spherical aberration signal corresponding to each of the plurality of optical disks. It becomes possible to do. The spherical aberration signal for each of the plurality of optical discs becomes uniform. Therefore, the operation control unit can control the operation of the focus tracking unit at a timing corresponding to each of the plurality of optical disks.

  In the control device for the optical pickup of the present invention, the operation control means may be configured to detect the spherical aberration signal when the correction of the spherical aberration for the recording layer to which the focus jump has been completed, at a predetermined time before reaching the value of the spherical aberration signal. Preferably, the value of the spherical aberration signal is set as a threshold value, and the focus jump driving means is operated when the value of the spherical aberration signal for the recording layer to which the focus jump is made reaches the threshold value.

  As a result, a predetermined time before reaching the value of the spherical aberration signal shown when the correction of the spherical aberration for the recording layer to which the focus jump is completed is the time when the focus jump driving means is operated by the operation control means. Therefore, the focus driving unit operates at a time before the correction of the spherical aberration is completed.

  Therefore, the operation of the focus jump driving means can be started earlier than the operation of the focus jump driving means is started after waiting for the correction of the spherical aberration. As a result, it is possible to shorten the time required to start the focus jump during the interlayer jump process.

  Further, in the control device for the optical pickup of the present invention, a focus error detection unit that detects a shift between a focusing position of the condensing optical system and a focus with respect to the recording layer as a focus error signal, and based on the focus error signal A focus tracking means for causing the focus position to follow the focus, and the threshold value is a time when the amplitude value of the focus error signal is at a level at which the focus tracking means can be stably operated. It is preferable that the value falls within a range corresponding to the value of the spherical aberration error signal.

  Thus, the threshold value falls within a range corresponding to the value of the spherical aberration error signal at the time when the amplitude value of the focus error signal is at a level at which the focus follower can be stably operated. In the pickup control device, the focus follower can be operated stably.

  Further, since the threshold value corresponds to the value of the aberration error signal at the time before reaching the value of the spherical aberration signal shown when the correction of the spherical aberration for the recording layer to which the focus jump is completed is completed, the conventional spherical aberration The operation of the focus drive means is started by the operation control means at a time before the completion of the correction. That is, it becomes possible to start the operation of the focus driving means earlier than before.

  As a result, the focus follower can operate stably, and the time taken to start the focus jump during the interlayer jump process can be shortened.

  In the control device for an optical pickup according to the present invention, the threshold value of the spherical aberration error signal at the time when the amplitude value of the focus error signal reaches a level at which the focus follower can be stably operated. It is preferably a value.

  As a result, the threshold value corresponds to the value of the spherical aberration error signal when the amplitude value of the focus error signal reaches a level at which the focus follower can be stably operated. In the recording / reproducing apparatus, the focus follower can be operated stably.

  Further, since the threshold value corresponds to the value of the aberration error signal at the time before reaching the value of the spherical aberration signal shown when the correction of the spherical aberration for the recording layer to which the focus jump is completed is completed, the conventional spherical aberration The operation of the focus drive means is started by the operation control means at a time before the completion of the correction.

  Furthermore, when the amplitude value of the focus error signal reaches a level at which the focus follower can operate stably, the amplitude value of the focus error signal reaches the level at which the focus follower can operate stably for the first time. This is the point. Therefore, the time point at which the level is reached is the earliest time point during which the operation of the focus follower can be stably started.

  Therefore, the operation of the focus tracking unit can be started at the earliest time point during which the operation of the focus tracking unit can be stably started.

  In addition, the optical pickup control device of the present invention preferably includes a storage unit for storing the threshold value.

  Thus, even when recording / reproduction is performed while changing the optical disk in the optical disk apparatus provided with the control device for the optical pickup of the present invention, the threshold value for each optical disk can be stored in the storage unit. That is, when the threshold is incorporated in the program, it is difficult to incorporate the threshold corresponding to each optical disc in the program in advance, whereas the threshold corresponding to each optical disc is stored. Can do.

  Therefore, by using the threshold information corresponding to each optical disk stored in the storage unit, it is easy to retract the focus tracking means for each optical disk at a timing at which the focus tracking means can be retracted. Will be possible.

  Further, in the control device for an optical pickup of the present invention, based on a correction signal acquisition unit that acquires a correction signal for correcting the threshold value from the reflected light of the optical disc, and the correction signal acquired by the correction signal acquisition unit, It is preferable that the operation control unit controls the operation of the focus jump driving unit in accordance with the threshold value corrected by the threshold value correction unit.

  The threshold is a spherical aberration signal. Since the spherical aberration signal is obtained from part of the reflected light from the optical disk surface, the threshold value varies in proportion to the value of the correction signal from the reflected light from the optical disk.

  Thereby, the threshold value corresponding to each of the plurality of optical discs can be corrected by correcting the threshold value by the threshold value correcting unit in accordance with the correction signal from the reflected light of each of the plurality of optical discs acquired by the correction signal acquiring unit. It becomes possible. Therefore, even if the same threshold value is initially set for each of a plurality of optical disks, the threshold value corresponding to each of the plurality of optical disks is reset.

  Therefore, when recording / reproduction is performed while changing the optical disk in the optical disk apparatus equipped with the optical pickup control device of the present invention, a threshold value corresponding to each optical disk is set without changing the threshold value initially set for each optical disk. Will be.

  In the control device for the optical pickup of the present invention, the operation control means may operate the focus follow-up means at a timing corresponding to each of the plurality of optical discs according to the threshold value corresponding to each of the plurality of optical discs. preferable.

  As a result, when recording / reproduction is performed while changing the optical disk in the optical disk apparatus provided with the control device for the optical pickup of the present invention, the threshold corresponding to each optical disk is set.

  Therefore, the operation control unit can operate the focus tracking operation at a timing at which the focus tracking unit can be stably operated for each optical disc. Therefore, even if the optical disk is changed, the focus follower can be operated stably.

  In order to solve the above problems, an optical disc apparatus according to the present invention includes an optical pickup having a light source and a condensing optical system that collects irradiation light from the light source on the optical disc, and any one of the optical pickups described above And a control device.

  According to the above invention, since any one of the above-described optical pickup control devices is provided, it is possible to shorten the time required to start the focus jump.

  In order to solve the above problem, an optical pickup control method of the present invention is an optical pickup control method including a condensing optical system that condenses irradiation light from a light source on an optical disc having a plurality of recording layers. A spherical aberration detecting step of detecting spherical aberration generated in the condensing optical system as a spherical aberration signal by the spherical aberration detecting means; and a focus position of the condensing optical system and a focal point with respect to the recording layer by the focus error detecting means. A focus error detection step for detecting a deviation of the focus as a focus error signal, a focus follow-up means for causing the focus position to follow the focus based on the focus error signal by a focus follow-up means, and a focus position change means, A focal position change that moves the objective lens of the condensing optical system and changes the focal position of the irradiation light. A focus jump driving step for instructing the focus position changing means to drive so as to perform a focus jump for moving the in-focus position between recording layers of the optical disc by a focus jump driving means, and an operation control means, An operation control step of operating and controlling the focus jump driving means in accordance with the value of the spherical aberration signal. In the operation control step, the spherical aberration when the correction of the spherical aberration for the recording layer to which the focus jump is completed is completed. The value of the spherical aberration signal at a predetermined time before reaching the value of the signal is used as a threshold value, and when the value of the spherical aberration signal for the recording layer of the focus jump reaches the threshold value, the focus jump driving step is performed. It is characterized by starting.

  According to the above invention, the focus jump driving process is started by the operation control process at a predetermined time before reaching the value of the spherical aberration signal when the correction of the spherical aberration for the recording layer of the focus jump destination is completed. Therefore, the focus driving process starts at a time before the correction of the spherical aberration is completed.

  Accordingly, the focus jump driving process can be started earlier than the start of the focus jump driving process after waiting for the correction of the spherical aberration. As a result, it is possible to shorten the time taken until the focus jump in the process of the interlayer jump starts.

  Further, the focus tracking process is stably started by setting the threshold value to the value of the spherical aberration error signal when the amplitude value of the focus error signal is at a level at which the focus tracking process can be stably started. It is possible to start the focus follow-up process at a time when it can be performed.

  According to the present invention, the operation control means can flexibly determine the timing for operating the focus jump driving means according to the spherical aberration signal while monitoring the changing spherical aberration signal. That is, it is possible to operate the focus jump driving means at a timing at which a focus jump is possible even if correction of the spherical aberration is not completed for the recording layer to which the focus jump is made. Therefore, it is possible to start the operation of the focus jump driving means earlier than the operation of the focus jump driving means after waiting for the correction of the spherical aberration to be completed.

  Therefore, there is an effect that it is possible to reduce the time required to start the focus jump in the process of the interlayer jump.

  Before describing the embodiments of the present invention, the configuration of an optical disc recording / reproducing apparatus common to the embodiments will be described with reference to FIGS.

  FIG. 1 shows a main configuration of the optical disc recording / reproducing apparatus. FIG. 2 shows the main structure of the optical pickup 7 in the optical disc recording / reproducing apparatus 30. The optical disk recording / reproducing apparatus 30 is an apparatus for recording and reproducing information with respect to the optical disk 1. The optical disk 1 may be an optical disk, and the type thereof is not limited, for example, a magneto-optical disk.

  As shown in FIG. 1, the optical disk recording / reproducing apparatus 30 includes an optical pickup 7, various motors 8, 11, 22, various drivers 10, 12, 13, 14, 23, 25, and an RF (high frequency) processing circuit 9. , Various control circuits 15, 16, 18, a signal processing circuit 17, and various external I / Fs (interfaces) 19. The optical disc recording / reproducing apparatus 30 is connected to the host computer 20 via the host interface 19. The optical disc recording / reproducing device 30 is connected to the display device 21.

  First, the drive part of the optical disc recording / reproducing apparatus 30 will be described. The spindle motor 11 rotates the optical disc 1. The spindle motor 11 includes a circuit that generates a pulse signal as the motor rotates, and this pulse signal is transmitted to a servo DSP (Digital Signal Processor) 16.

  The optical pickup 7 irradiates the optical disc 1 with a light beam to record / reproduce information on the optical disc 1. The sled motor 8 drives the optical pickup 7 in the radial direction with respect to the optical disc 1. The tilt motor 22 adjusts the tilt of the optical pickup 7 with respect to the optical disc 1.

  As shown in FIGS. 1 and 2, the optical pickup 7 includes an objective lens (OL, condensing optical system) 2, an actuator 3, a semiconductor laser (LD, light source) 4, photodetectors (PD) 5 and 6, A tilt sensor 24, a collimating lens (CL, condensing optical system) 26, a collimating lens driving mechanism 27, a beam splitter 28, and a mirror (condensing optical system) 32 are provided.

  The semiconductor laser 4 is a light source for irradiating the optical disk 1 with a light beam, and emits the light beam. The wavelength of the light beam emitted from the semiconductor laser 4 is defined by a standard such as DVD (Digital Versatile Disk).

  The beam splitter 28 reflects a part of the light beam emitted from the semiconductor laser 4 to guide it to the photodetector 5 and transmits the remaining most part. The beam splitter 28 reflects reflected light from the optical disc 1 and guides it to the photodetector 6. A hologram can be used instead of the beam splitter 28.

  The photodetectors 5 and 6 have a light receiving element and convert light incident on the light receiving element into an electric signal. The photodetector 5 detects a part of the direct light from the semiconductor laser 4 in order to detect the power of the light beam emitted from the semiconductor laser 4, and transmits the detected signal to the automatic output control circuit 15. To do. On the other hand, the photodetector 6 is for detecting reflected light from the optical disc 1 and transmits various signals such as a detected servo error signal, RF signal, and wobble signal to the RF processing circuit 9.

  Here, the RF signal and the wobble signal are signals (reproduction signals) recorded on the optical disc 1. The RF signal indicates data recorded on the optical disc 1, and the wobble signal indicates an address on the optical disc 1. Normally, the photodetector 5 has one light receiving element, and the photodetector 6 has a plurality of light receiving elements.

  The collimating lens 26 collects the light beam emitted from the semiconductor laser 4 and passed through the beam splitter 28 and converts it into substantially parallel light. In the present embodiment, the collimating lens 26 is movable in the optical axis direction by the collimating lens driving mechanism 27 in order to correct the spherical aberration of the light beam applied to the optical disc 1.

  As shown in FIG. 2, the collimating lens driving mechanism 27 includes a stepping motor 33 that generates a rotational force, a feed screw 34 to which the rotational force is transmitted from a rotation shaft of the stepping motor 33 via a gear, and a feed screw. 34 and a holder 35 that holds the collimating lens 26.

  The stepping motor 33 is a motor that rotates a rotating shaft by a predetermined angle when a predetermined pulse current flows. The feed screw 34 is provided such that its axial direction is parallel to the optical axis direction of the collimating lens 26. Thereby, the rotational movement in the feed screw 34 is converted into the linear movement in the optical axis direction of the collimating lens 26 by the holder 35. As a result, the collimating lens 26 can be moved in the optical axis direction.

  As shown in FIG. 2, the mirror 32 is disposed between the collimating lens 26 and the objective lens 2, bends the light beam from the collimating lens 26 and guides it to the objective lens 2, and from the objective lens 2. The light beam is bent and guided to the collimating lens 26.

  The objective lens 2 is for condensing the light beam from the semiconductor laser 4 on the optical disc 1 and guiding the reflected light from the optical disc 1 to the photodetector 6. The objective lens 2 is driven by an actuator 3.

  The actuator 3 drives the objective lens 2. The actuator 3 is driven and controlled by an actuator driver (focus position changing means) 13.

  Specifically, the actuator 3 drives the objective lens 2 in the focus direction that is the optical axis direction of the objective lens 2 and the radial direction that is the radial direction of the optical disc 1. The actuator 3 has a focus coil 52 (see FIG. 3) that is a voice coil that drives the objective lens 2 in the focus direction, and a tracking coil that is a voice coil that drives the objective lens 2 in the radial direction as a drive mechanism of the objective lens 2. 56 (see FIG. 4). In addition to the voice coil, a known drive mechanism can be used as the drive mechanism of the actuator 3.

  The tilt sensor 24 is a sensor for detecting a tilt angle between the optical pickup 7 and the optical disc 1. Here, the tilt angle refers to an angle formed by the normal direction of the recording surface of the optical disc 1 and the optical axis direction of the objective lens 2. If the tilt angle is large, the quality of recording and / or reproduction is deteriorated. Therefore, the tilt sensor 24 detects the tilt angle (tilt error), and the tilt motor 22 adjusts the tilt of the optical pickup 7 based on the tilt angle. As a result, the optimum recording and / or reproduction quality can be maintained.

  Next, the circuit portion of the optical disc recording / reproducing apparatus 30 will be described. The thread driver 10, spindle motor driver 12, actuator driver 13, tilt driver 23, and collimating lens drive motor driver 25 drive control the thread motor 8, spindle motor 11, actuator 3, tilt motor 22, and stepping motor 33, respectively. To do.

  The laser driver 14 controls the driving of the semiconductor laser 4. The automatic output control circuit (APC) 15 compares the laser light detection level detected by the photodetector 5 with a reference level serving as a reference, controls the laser driver 14 based on the comparison result, and controls the laser. Make the light output constant. Specifically, the APC circuit 15 controls the laser driver 14 to lower the laser light output when the detection level is higher than the reference level and to increase the laser light output when the detection level is lower than the reference level. To do.

  Further, when recording data on the optical disk 1, the laser driver 14 drives and controls the semiconductor laser 4 based on the recording signal received from the signal processing circuit 17. The semiconductor laser 4 at the time of recording emits pulses, but emits light at a recording power, so that the level of the reflected signal from the optical disk 1 detected by the photodetector 6 is larger than that at the time of reproduction. turn into. For this reason, the photodetector 6 has a function of performing gain switching between reproduction and recording. As a result, the level of the servo error signal sent to the RF processing circuit 9 during recording is prevented from increasing. During recording, the APC circuit 15 performs an APC operation so that the semiconductor laser 4 emits light with a power suitable for recording.

  The laser driver 14 performs write strategy processing when recording data on the optical disc 1. The write strategy process is a process of changing the recording method according to a subtle difference of the optical disk 1 when the recording signal is actually recorded on the optical disk 1. The write strategy process utilizes the fact that recording on the optical disc 1 is thermal recording. Recording performance can be improved by the write strategy processing.

  The RF processing circuit 9 performs IV conversion of a signal sent from the photodetector 6 from a current signal to a voltage signal. The RF processing circuit 9 outputs the converted voltage signal to the signal processing circuit 17 and outputs it to the servo DSP 16 via the A / D converter (see FIGS. 3 and 4).

  More specifically, the RF processing circuit 9 performs IV conversion on the reproduction signal from the photodetector 6, performs waveform shaping processing, and transmits the result to the signal processing circuit 17. Further, the RF processing circuit 9 performs IV conversion on the servo error signal from the photodetector 6, performs waveform shaping processing, and then transmits it to the servo DSP 16 via the A / D converter. .

  The servo DSP 16 performs various arithmetic processes based on the servo error signal received from the photodetector 6 via the RF processing circuit 9, and performs errors for various servos such as focus servo, tracking servo, and aberration servo for the objective lens. Generate a signal. A known method can be used to generate each error signal. For example, a focus error signal that is an error signal for focus servo can be generated by an astigmatism method or a knife edge method. A tracking error signal that is an error signal for tracking servo can be generated by a differential push-pull method. In addition, an aberration error signal, which is an error signal for aberration servo, can be generated by differential focus error signals between the central portion and the peripheral portion of the light beam.

  The servo DSP 16 generates a drive instruction signal for driving the actuator 3 based on the generated focus error signal and tracking error signal, and transmits the drive instruction signal to the actuator driver 13. The actuator driver 13 drives and controls the actuator 3 based on the drive instruction signal. Thereby, focus servo and tracking servo control for the actuator 3 is performed. Details of the focus servo and tracking servo will be described later.

  When the servo DSP 16 receives from the system controller 18 a jump instruction signal instructing to jump to a certain track of the optical disc 1, a thread drive instruction for driving the sled motor 8 based on the received jump instruction signal. A signal is generated and transmitted to the thread driver 10. The thread driver 10 drives and controls the thread motor 8 based on the received thread drive instruction signal. The servo DSP 16 may generate a thread drive instruction signal for driving the thread motor 8 based on the tracking servo error signal, and transmit the thread drive instruction signal to the thread driver 10. In this case, tracking servo for the optical pickup 7 is performed.

  The servo DSP 16 generates a drive instruction signal for driving the spindle motor 11 at an appropriate rotational speed based on the pulse signal received from the spindle motor 11, and transmits the drive instruction signal to the spindle motor driver 12. The spindle motor driver 12 drives and controls the spindle motor 11 based on the received drive instruction signal.

  Further, the servo DSP 16 generates a tilt drive instruction signal for driving the optical pickup 7 to an appropriate tilt based on the tilt error signal received from the tilt sensor 24 via the RF processing circuit 9, and the tilt driver 23. Send to. The tilt driver 23 drives and controls the tilt motor 22 based on the received tilt drive instruction signal.

  The servo DSP 16 generates a drive instruction signal for driving the collimator lens 26 based on the generated aberration error signal, and transmits the drive instruction signal to the collimator lens drive motor driver 25. The collimating lens driving motor driver 25 drives and controls the collimating lens driving mechanism 27 (stepping motor 33) based on the driving instruction signal. Thereby, servo control for the collimating lens 26, that is, spherical aberration servo is performed. Details of the spherical aberration servo will be described later.

  On the other hand, the signal processing circuit 17 performs processing such as demodulation and waveform shaping on the RF signal in the reproduction signal, and further performs error correction processing to reproduce the original data. The reproduced data is transmitted from the signal processing circuit 17 to the host computer 20 via the host interface 19.

  Similarly, the signal processing circuit 17 performs processing such as demodulation, waveform shaping, and error correction on the wobble signal in the reproduction signal to reproduce the address signal. The reproduced address signal is transmitted from the signal processing circuit 17 to the system controller 18 and used as address information by the system controller 18.

  The signal processing circuit 17 generates a clock signal from each of the RF signal and the wobble signal. A synchronization signal is generated from this clock signal. For example, the clock signal is transmitted to the servo DSP 16 and used to control the rotation of the spindle motor 11 in synchronization with the RF signal.

  The signal processing circuit 17 receives data from the host computer 20 via the host interface 19 when recording data on the optical disc 1. The signal processing circuit 17 adds a flag for error correction to the received data, further performs modulation processing, and then transmits it to the laser driver 14 as a recording signal.

  The system controller 18 is for overall control of various components in the optical disc recording / reproducing apparatus 30. The function of the system controller 18 is realized by the CPU executing a program stored in a storage device such as a RAM or a flash memory.

  Next, details of the focus servo, tracking servo, and spherical aberration servo will be described with reference to FIGS. FIG. 3 shows a configuration relating to focus servo and spherical aberration servo in the optical disc recording / reproducing apparatus 30. FIG. 4 shows a configuration related to tracking servo in the optical disc recording / reproducing apparatus 30.

  As shown in FIGS. 3 and 4, the servo DSP 16 includes a servo controller 40, an error signal generation circuit (spherical aberration detection means, focus error detection means) 41, and various focus servo compensation circuits (focus follow-up means, focus jump drive). Means) 42, ramp circuit 43, aberration servo compensation circuit 44, jump control circuit 45, stepping motor control circuit 46, tracking servo compensation circuit 47, track jump control circuit 48, and various switches SW1 to SW6. .

  The servo controller 40 performs overall control of various components in the servo DSP 16. Specifically, the servo controller 40 controls the focus servo various compensation circuits 42 and the tracking servo various compensation circuits 47 based on the instruction signal from the system controller 18 and various error signals from the error signal generation circuit 41. Or controls turning on / off of the switches SW1 to SW6. The details of the servo controller 40 will be described in each embodiment.

  The error signal generation circuit 41 performs various arithmetic processing based on the error signal received from the photodetector 6 via the RF processing circuit 9 (see FIG. 1) and the A / D converter 36, and based on the calculation result, A focus error signal, a tracking error signal, and an aberration error signal (spherical aberration signal) are generated. The error signal generation circuit 41 transmits a focus error signal to the focus servo various compensation circuits 42, a tracking error signal to the tracking servo various compensation circuits 47, and an aberration error signal to the aberration servo various compensation circuits 44. In addition, the error signal generation circuit 41 transmits the generated focus error signal, tracking error signal, and aberration error signal to the servo controller 40.

  The various focus servo compensation circuits 42 generate a drive instruction signal for driving the focus coil 52 of the actuator 3 based on the focus error signal. At this time, the focus servo compensation circuit 42 performs various compensations in order to drive the focus coil 52 optimally. Examples of this compensation include phase compensation.

  The ramp circuit 43 generates a drive instruction signal for moving the objective lens 2 from the initial position before the operation to a position where focus servo is performed.

  The switch SW2 switches between a drive instruction signal from the focus servo compensation circuit 42 and a drive instruction signal from the ramp circuit 43 based on an instruction from the servo controller 40. The switch SW1 selects whether or not to send a drive instruction signal from the focus servo various compensation circuit 42 or the ramp circuit 43 to the actuator driver 13 based on an instruction from the servo controller 40. The focus servo is turned on / off by the switch SW1.

  The drive instruction signal from the focus servo compensation circuit 42 or the ramp circuit 43 via the switch SW2 and the switch SW1 is converted into an analog signal by the D / A converter 50, and then the focus driver 51 of the actuator driver 13. Is input. The focus driver 51 controls the drive of the focus coil 52 by converting the drive instruction signal into an appropriate signal level and inputting it to the focus coil 52. Thereby, the objective lens 2 can be moved to a desired position in the optical axis direction.

  On the other hand, the various aberration servo compensation circuits 44 generate a movement instruction signal for moving the collimator lens 26 to a position based on the aberration error signal. At this time, the various aberration servo compensation circuits 44 perform various compensations in order to optimally drive the collimating lens drive motor 33.

  The jump control circuit 45 generates a movement instruction signal for moving the collimator lens 26 from the initial position before the operation to a position where the aberration servo is performed.

  The switch SW4 switches between a movement instruction signal from the aberration servo compensation circuit 44 and a movement instruction signal from the jump control circuit 45 based on an instruction from the servo controller 40. The switch SW3 selects whether or not to send a movement instruction signal from the aberration servo compensation circuit 44 or the jump control circuit 45 to the stepping motor control circuit 46 based on an instruction from the servo controller 40. The aberration servo is turned on / off by the switch SW3.

  The stepping motor control circuit 46 generates a drive instruction signal for driving the collimating lens drive motor 33 that is a stepping motor based on the movement instruction signal from the various aberration servo compensation circuit 44 or the jump control circuit 45.

  The drive instruction signal generated by the stepping motor control circuit 46 is converted into an analog signal by the D / A converter 53 and then input to the collimating lens drive motor driver 25. The collimating lens driving motor driver 25 controls the driving of the collimating lens driving motor 33 by converting the driving instruction signal into an appropriate signal level and inputting it to the collimating lens driving motor 33. Thereby, the collimating lens 26 moves in the optical axis direction.

  When the collimating lens 26 is movable in the optical axis direction, the light beam transmitted from the semiconductor laser 4 through the collimating lens 26 is changed to a light beam slightly diverged from a parallel light beam, or light slightly converged from a parallel light beam. Or a beam. Thereby, the spherical aberration of the light beam condensed on the optical disk 1 can be corrected.

  On the other hand, as shown in FIG. 4, the tracking servo various compensation circuit 47 generates a drive instruction signal for driving the tracking coil 56 of the actuator 3 based on the tracking error signal. At this time, the tracking servo compensation circuit 47 performs various compensations in order to drive the tracking coil 56 optimally. Examples of this compensation include phase compensation and gain adjustment.

  The track jump control circuit 48 generates a drive instruction signal for moving the objective lens 2 from the initial position before the operation to a position for performing tracking servo.

  The switch SW6 switches between a drive instruction signal from the tracking servo compensation circuit 47 and a drive instruction signal from the track jump control circuit 48 based on an instruction from the servo controller 40. The switch SW5 selects whether or not to send a drive instruction signal from the tracking servo compensation circuit 47 or the track jump control circuit 48 to the actuator driver 13 based on an instruction from the servo controller 40. The tracking servo is turned on / off by the switch SW5.

  A drive instruction signal from the tracking servo compensation circuit 47 or the track jump control circuit 48 via the switch SW6 and the switch SW5 is converted into an analog signal by the D / A converter 54, and then is used for tracking of the actuator driver 13. Input to the driver 55. The tracking driver 55 controls the drive of the tracking coil 56 by converting the drive instruction signal into an appropriate signal level and inputting it to the tracking coil 56. Thereby, the objective lens 2 can be moved to a desired position in the radial direction.

[Embodiment 1]
One embodiment of the present invention will be described below with reference to FIGS. The configuration other than that described in the present embodiment is the same as the configuration of the optical disc recording / reproducing apparatus common to the above-described embodiments. For convenience of explanation, members having the same functions as those shown in the drawings used for explaining the configuration of the optical disc recording / reproducing apparatus common to the embodiments are given the same reference numerals, and explanation thereof is omitted. .

  First, the configuration of the servo controller (operation control means) 40 will be described with reference to FIG.

  The servo controller 40 includes a storage unit 401 and a calculation unit 402 as shown in FIG.

  The storage unit 401 stores in advance a value (threshold value) of an aberration error signal necessary for drawing the focus servo (operating the focus servo various compensation circuits 42 stably). The threshold value is a value of an aberration error signal corresponding to the value of the focus servo gain as the gain ratio necessary for pulling in the focus servo, and will be described in detail later.

  The computing unit 402 refers to the value of the aberration error signal transmitted from the error signal generation circuit 41 and the threshold value stored in the storage unit 401, and performs computation according to a predetermined procedure. Then, according to the result of the above calculation, the focus servo various compensation circuit 42 is instructed to drive the actuator driver 13 to perform the focus jump.

  For example, the calculation unit 402 compares the value of the aberration error signal with the threshold value. When the value of the aberration error signal has reached the threshold value, the focus servo various compensation circuit 42 is instructed to drive the actuator driver 13 to perform a focus jump. As a result, a focus jump is performed.

  Further, the calculation unit 402 compares, for example, the value of the aberration error signal with the threshold value. When the value of the aberration error signal does not reach the threshold value, the focus servo various compensation circuit 42 is instructed not to drive the actuator driver 13 to perform the focus jump.

  The storage unit 401 and the calculation unit 402 are functional blocks that are realized by the CPU executing a program stored in the storage device and controlling peripheral circuits such as an input / output circuit (not shown).

  In the present embodiment, the threshold information is stored in the storage unit 401. However, the present invention is not limited to this. For example, the threshold value information is incorporated into a program executed by the calculation unit 402. A configuration without 401 may be employed.

  Further, the threshold value corresponding to the aberration error signal detected for each optical disk 1 may be set for each optical disk 1 every time the optical disk 1 to be recorded or reproduced is switched.

  Next, the focus jump timing when performing an interlayer jump in the optical disc 1 having a plurality of recording layers will be described with reference to FIGS.

  The interlayer jump referred to here indicates an operation of moving the recording layer for recording or reproduction on the optical disc. Further, the focus jump is an operation during the process of the interlayer jump, and indicates an operation of moving the focus position of the light irradiated from the condensing optical system from one recording layer to the other recording layer. .

  FIG. 6 schematically shows changes in the aberration error signal when a focus jump is performed from one recording layer (L0 layer) of the optical disc 1 to the other recording layer (L1 layer). In FIG. 6, the position of the collimating lens (CL) 26 when the focus is on the L0 layer is represented as L0, and the position of the CL 26 when the focus is on the L1 layer is represented as L1. The distance from L0 to L1 is about 25 μm as an example. The change in the aberration error signal when the CL 26 is driven from the semiconductor laser (LD) 4 side to the objective lens (OL) 2 side when the focus is on the L0 layer or the L1 layer is indicated by a broken line.

  A case where a focus jump is performed from the L0 layer to the L1 layer will be described as an example. In FIG. 6, the focus jump is performed when the CL 26 is positioned at an intermediate point between L0 and L1. That is, the threshold corresponding to the voltage corresponding to the aberration error signal when the CL 26 that is in focus on the L0 layer is located at a position of 12.5 μm, which is an intermediate point between L0 and L1.

  First, in a state where the L0 layer is focused and aberration correction for the L0 layer is completed, the aberration error signal becomes 0 at the time of L0 as shown in FIG. Subsequently, as the CL 26 is driven from the position L0 to the OL2 side, the absolute value of the aberration error signal increases unless the aberration servo is applied. Then, when the threshold value for starting the focus jump is reached, the focus jump is performed, and the focus moves to the L1 layer. Immediately after the focus is moved to the L1 layer, since the focus is not completely aligned with the L1 layer, the absolute value of the aberration error signal becomes larger than 0 as shown in FIG. After that, by applying focus servo and spherical aberration servo, as shown in L1, the aberration error signal is 0, the L1 layer is in focus, and the aberration correction for the L1 layer is completed.

  7A to 7C show changes in the focus error signal, the aberration error signal, and the RF signal that are actually measured when the focus jump is performed.

  7 (a) and 7 (b) are diagrams when a focus jump is performed from the L0 layer to the L1 layer, and FIG. 7 (b) is a partially enlarged view of FIG. 7 (a). Is. FIG. 7C is a diagram when a focus jump is performed from the L1 layer to the L0 layer.

  As shown in FIGS. 7A to 7C, a change similar to the change in the aberration error signal accompanying the focus jump represented by the thick line in FIG. 6 is actually recognized. The focus jump ends when the focus error signal vibrates once in the vertical direction. Thereafter, the focus error signal converges to 0 level by the focus servo. Accordingly, in FIG. 7A to FIG. 7C, the vibration of the focus error signal is detected only once for one focus jump. This means that the focus error signal converges quickly after the focus jump. Means that

  Next, the threshold value for determining the timing for performing the focus jump by controlling the operation of the focus servo various compensation circuit 42 by the servo controller 40 will be described in detail with reference to FIG.

  As described above, the threshold value is a value of an aberration error signal necessary for pulling in the focus servo. Further, it is generally known that a focus servo gain value greater than a certain value is required for the focus servo pull-in. That is, the value of the aberration error signal necessary for pulling in the focus servo represents the value of the aberration error signal at the time when the value of the focus servo gain necessary for pulling in the focus servo is shown.

  The reason why the value of the focus error signal is not used as the threshold value is that the focus error signal is generated only when a focus jump is performed, as shown in FIGS. This is because the timing for performing the focus jump cannot be determined while monitoring the temporal change of the focus error signal. Therefore, in the present invention, the value of the aberration error signal at the time point indicating the value of the focus servo gain necessary for the focus servo pull-in is used as the threshold value.

  Next, a method for actually obtaining the value of the aberration error signal corresponding to the value of the focus servo gain necessary for pulling in the focus servo will be described.

  First, after the CL 26 is driven by a predetermined pulse by the stepping motor 33, a focus jump is performed and a focus error signal is measured. For example, the focus error signal is measured while changing the driving distance by 10 pulses, and the correlation between the number of pulses and the value of the focus error signal is graphed.

  In FIG. 8, the correlation between the number of pulses and the ratio of the focus error signal value (gain ratio, focus servo gain) when the CL 26 is actually driven from 0 pulse to 170 pulses for a two-layer optical disc is This is shown in the graph by the method described above. In FIG. 8, a line graph is created by plotting the gain ratio at each pulse number in order. FIG. 8 is a graph showing changes in the gain ratio when the L0 layer is in focus with respect to the focus gain at the CL optimum position. The graph also shows the change in the gain ratio when the L1 layer is in focus with respect to the focus gain at the CL optimum position.

  Since the vertical axis in FIG. 8 is a logarithm with respect to the focus gain at the CL optimum position, the CL optimum position is the time when the gain ratio on the vertical axis shows 0 dB. The CL optimum position is the position of CL26 when the L0 layer and the L1 layer are in focus. Therefore, the position where the gain ratio is 0 dB is focused on the L0 layer and the L1 layer. It becomes the position of CL26 when it is in agreement. In FIG. 8, the point where the number of pulses is about 50 is the optimum CL position for the L0 layer, and the point where the number of pulses is about 120 is the optimum CL position for the L1 layer.

The value of the gain ratio at which focus servo can be pulled from the L0 layer to the L1 layer is a value when the absolute value of the difference between the gain ratio for the L1 layer and the gain ratio for the L0 layer is less than about 10 dB. . Therefore, in the case of FIG. 8, the focus servo can be pulled in when the number of pulses is in the range between about 65 and about 105. Therefore, the number of pulses is in the range between about 65 and about 105. The value of the aberration error signal at a certain time can be set to the value of the aberration error signal that can be used for focus servo pull-in. Therefore, it is possible to determine the timing at which the focus servo can be pulled in based on the value of the aberration error signal. In order to perform focus jump more stably, it is preferable to perform focus servo pull-in at a point (intermediate point) where the gain ratio for the L0 layer and the gain ratio for the L1 layer are equal. In the case of FIG. 8, a point where the number of pulses is about 80 is an intermediate point.

  In the example shown in FIG. 6, focus jump is performed using the value of the aberration error signal at the time between the CL optimum position for the L0 layer and the CL optimum position for the L1 layer as the threshold value. Therefore, in the example shown in FIG. 6, the focus jump is performed at the position where the number of pulses in the case of FIG. 8 is about 85. In the case of FIG. 8, the focus servo can be pulled in when the number of pulses is in the range between about 65 and about 105. Therefore, in the focus jump of FIG. The focus servo can be pulled in.

  Further, the number of pulses of about 85 at a time point between the CL optimum position for the L0 layer and the CL optimum position for the L1 layer, the gain ratio for the L0 layer that can perform focus jump more stably, and the L1 layer Since the number of pulses at the point where the gain ratio is equal (intermediate point) is approximately 80, it is an aberration at a point in time between the CL optimum position for the L0 layer and the CL optimum position for the L1 layer. The value of the error signal may be set as the above threshold value at which the focus jump can be performed more stably.

  As shown in FIG. 8, when a focus jump from the L0 layer to the L1 layer is performed, approximately 55 pulses are required rather than CL reaching the optimal CL position for the L1 layer, which is also a position where aberration correction for the L1 layer is completed. The focus servo can be pulled in from the previous time.

  In the present invention, the threshold value includes a time point approximately 55 pulses before the CL 26 reaches the optimal CL position for the L1 layer. Therefore, according to the present invention, a time point approximately 55 pulses before the correction is completed. It is actually possible to perform a focus jump with. In other words, it is actually possible to perform the focus jump approximately 55 pulses before the conventional focus jump after the correction is completed.

  Subsequently, an operation flow in the optical disc recording / reproducing apparatus 30 of the present embodiment will be described with reference to flowcharts shown in FIGS.

  First, FIG. 9 shows an operation flow in the optical disc recording / reproducing apparatus 30 in the case where the CL 26 is driven by the number of pulses corresponding to the distance between the recording layers where the focus jump is performed during the interlayer jump.

  First, an interlayer jump in the optical disc recording / reproducing apparatus 30 is started. When the interlayer jump starts, in step S401, the thread servo, tracking servo, and aberration servo are turned off.

  Subsequently, in step S402, it is determined whether the focus jump is performed from the L0 layer to the L1 layer or from the L1 layer to the L0 layer by the servo DSP 16. If it is determined that the focus jump is performed from the L0 layer to the L1 layer (L0 → L1 in step S402), the process proceeds to step S403, and the number of pulses corresponding to the distance from the L0 layer to the L1 layer is set. The driving of the CL 26 to the OL2 side is started. Then, the process proceeds to step S404.

  If it is determined that the focus jump is performed from the L1 layer to the L0 layer (L1 → L0 in step S402), the process proceeds to step S411, and the number of pulses corresponding to the distance from the L1 layer to the L0 layer is set. The driving of the CL 26 to the LD4 side is started. Then, the process proceeds to step S412.

  Subsequently, in step S404, the calculation unit 402 in the servo controller 40 determines whether the value of the aberration error signal has reached the focus jump start threshold voltage (threshold). If the value of the aberration error signal has reached the threshold (YES in step S404), the process proceeds to step S405. On the other hand, if the value of the aberration error signal has not reached the threshold value (NO in step S404), the flow of step S404 is performed again.

  Also in step S412, the calculation unit 402 in the servo controller 40 determines whether the value of the aberration error signal has reached the focus jump start threshold voltage (threshold). If the value of the aberration error signal has reached the threshold (YES in step S412), the process proceeds to step S405. On the other hand, if the value of the aberration error signal has not reached the threshold value (NO in step S412), the flow of step S412 is performed again.

  In step S405, a focus jump is performed to the target recording layer.

  In step S406, the servo DSP 16 confirms whether the focus jump has been completed. If the focus jump has ended (YES in step S406), the process proceeds to step S407. On the other hand, if the focus jump has not ended (NO in step S406), the flow of step S406 is performed again.

  In step S407, it is confirmed by the servo DSP 16 whether the CL 26 has finished driving for the number of pulses (designated pulses) corresponding to the distance from L0 to L1. If the driving of the designated pulse has been completed (YES in step S407), the process proceeds to step S408. On the other hand, when the driving of the designated pulse has not ended (NO in step S407), the flow of step S407 is performed again.

  In step S408, the aberration servo is turned on, and the process proceeds to step S409.

  In step S409, the servo DSP 16 checks whether the value of the aberration error signal has reached 0 (the aberration error has crossed zero). If the value of the aberration error signal has reached 0 (YES in step S409), the process proceeds to step S410. On the other hand, if the value of the aberration error signal has not reached 0 (NO in step S409), the flow of step S409 is performed again.

  In step S410, the tracking servo and the sled servo are turned on. Then, the interlayer jump in the optical disc recording / reproducing apparatus 30 ends.

  According to the above configuration, the driving distance of the CL 26 can be adjusted by the number of pulses. Therefore, by driving the CL 26 in advance to a position where the aberration roughly matches after the focus jump, the aberration servo after the focus jump is achieved. It is possible to reduce the time required for the process.

  Next, FIG. 10 shows an operation flow in the optical disc recording / reproducing apparatus 30 when the CL 26 is driven without setting the driving distance in advance during the interlayer jump.

  First, the interlayer movement in the optical disc recording / reproducing apparatus 30 is started. When the interlayer jump starts, in step S421, the thread servo, tracking servo, and aberration servo are turned off.

  Subsequently, in step S422, it is determined whether the focus jump is performed from the L0 layer to the L1 layer or from the L1 layer to the L0 layer by the servo DSP 16. When it is determined that the focus jump is to be performed from the L0 layer toward the L1 layer (L0 → L1 in step S422), the process proceeds to step S423, and driving of the CL 26 to the OL2 side is started. Then, the process proceeds to step S424.

  If it is determined that the focus jump is to be performed from the L1 layer to the L0 layer (L1 → L0 in step S422), the process proceeds to step S431, and driving of the CL26 to the LD4 side is started. Then, the process proceeds to step S432.

  Subsequently, in step S424, the arithmetic unit 402 in the servo controller 40 determines whether the value of the aberration error signal has reached the focus jump start threshold voltage (threshold). If the value of the aberration error signal has reached the threshold value (YES in step S424), the process proceeds to step S425. On the other hand, if the value of the aberration error signal has not reached the threshold value (NO in step S424), the flow of step S424 is performed again.

  Also in step S432, the calculation unit 402 in the servo controller 40 determines whether the value of the aberration error signal has reached the focus jump start threshold voltage (threshold). If the value of the aberration error signal has reached the threshold value (YES in step S432), the process proceeds to step S425. On the other hand, when the value of the aberration error signal has not reached the threshold value (NO in step S432), the flow of step S432 is performed again.

  In step S425, the driving of CL26 is stopped. In step S426, a focus jump is performed to the target recording layer.

  In step S427, the servo DSP 16 confirms whether the focus jump has been completed. If the focus jump has ended (YES in step S427), the process proceeds to step S428. On the other hand, if the focus jump has not ended (NO in step S427), the flow of step S427 is performed again.

  In step S428, the aberration servo is turned ON, and the process proceeds to step S429.

  In step S429, the servo DSP 16 checks whether the value of the aberration error signal has reached 0 (the aberration error has crossed zero). If the value of the aberration error signal has reached 0 (YES in step S429), the process proceeds to step S430. On the other hand, if the value of the aberration error signal has not reached 0 (NO in step S429), the flow in step S429 is performed again.

  In step S430, the tracking servo and the sled servo are turned on. Then, the interlayer jump in the optical disc recording / reproducing apparatus 30 ends.

  According to the above configuration, it is possible to use, for the optical disc recording / reproducing apparatus 30, driving means that does not detect the position by the number of pulses, such as a DC motor.

  In addition, this invention is not limited to said embodiment, A various change is possible within the scope of the present invention. For example, in the above-described embodiment, after the aberration servo is turned on, it is configured to check whether the value of the aberration error signal has reached 0. However, the present invention is not particularly limited to this. For example, even if the aberration error signal does not reach 0, it may be configured to check whether the value of the aberration error signal has reached an allowable error range in which tracking servo and thread servo can be pulled.

  In this embodiment, the focus jump is performed after the aberration servo is turned off and the aberration servo is turned on after the focus jump is finished. However, the present invention is not limited to this, and the aberration servo is turned on. It is also possible to perform a focus jump while keeping

[Embodiment 2]
The following will describe another embodiment of the present invention with reference to FIG. The configurations other than those described in the present embodiment are the same as those of the optical disc recording / reproducing apparatus common to the above-described embodiments or the first embodiment. For convenience of explanation, the same reference numerals are used for members having the same functions as those shown in the drawings used in the description of the configuration of the optical disc recording / reproducing apparatus common to the embodiments or the first embodiment. A description thereof will be omitted.

  FIG. 11 is a functional block diagram of the servo controller 440. First, the configuration of the servo controller 440 will be described. As shown in FIG. 11, the servo controller 440 includes a storage unit 401, a calculation unit 412, and a total signal acquisition unit (correction signal acquisition unit) 413.

  The calculation unit (spherical aberration correction unit, threshold correction unit) 412 transmits the aberration error signal transmitted from the error signal generation circuit 41, the threshold information stored in the storage unit 401, and the total signal acquisition unit 413. The calculated total signal is referred to and calculated according to a predetermined procedure. Then, according to the result of the above calculation, the focus servo compensation circuit 42 is instructed to drive the actuator driver 13 to perform a focus jump.

  The total signal acquisition unit 413 acquires a total signal indicating the total amount of reflected light from the optical disc 1 from the signal processing circuit 17 and transmits it to the calculation unit 412.

  Next, processing in the calculation unit 412 when recording / reproduction is performed by the optical disc recording / reproducing apparatus 30 while switching the optical disc 1 will be described. Further, it is assumed that recording / reproduction of a plurality of recording layers is performed in the order of the optical disc 1a and the optical disc 1b.

  When recording / reproducing the optical disc 1a, the calculation unit 412 corrects the value of the aberration error signal according to the total signal of the optical disc 1a acquired by the total signal acquisition unit 413. Then, the corrected aberration error signal is compared with the threshold value. Subsequently, when the value of the corrected aberration error signal reaches the threshold value, the focus servo various compensation circuit 42 is instructed to drive the actuator driver 13 to perform a focus jump. As a result, a focus jump is performed.

  When the corrected aberration error signal value does not reach the threshold value, the focus servo various compensation circuit 42 is instructed not to drive the actuator driver 13 and perform a focus jump. Do.

  When recording / reproducing the optical disc 1b following recording / reproducing of the optical disc 1a, the calculation unit 412 corrects the value of the aberration error signal according to the total signal of the optical disc 1b acquired by the total signal acquisition unit 413. Then, the corrected aberration error signal is compared with the threshold value. Subsequently, when the value of the corrected aberration error signal reaches the threshold value, the focus servo various compensation circuit 42 is instructed to drive the actuator driver 13 to perform a focus jump. As a result, a focus jump is performed.

  When the corrected aberration error signal value does not reach the threshold value, the focus servo various compensation circuit 42 is instructed not to drive the actuator driver 13 and perform a focus jump. Do. In this way, each time the optical disk 1 to be recorded and reproduced is switched, the aberration error signal is corrected based on the total signal acquired by the total signal acquisition unit 413.

  The storage unit 401, the calculation unit 412 and the total signal acquisition unit 413 are functional blocks realized by the CPU executing a program stored in the storage device and controlling peripheral circuits such as an input / output circuit (not shown). .

  In the present embodiment, the threshold information is stored in the storage unit 401. However, the threshold information is not necessarily limited thereto. For example, the threshold information is incorporated into a program executed by the calculation unit 412. It is also possible to adopt a configuration that does not store in 401.

  Further, in the present embodiment, the aberration error signal is corrected by the calculation unit 412 based on the total signal acquired by the total signal acquisition unit 413. However, the present invention is not necessarily limited to this. For example, the total signal acquisition unit The calculation unit 412 may correct the threshold value based on the total signal acquired in 413.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

  For example, in the above embodiment, the collimator lens 26 is used as an adjustment mechanism for adjusting the spherical aberration, but any adjustment mechanism such as a solid immersion lens, a liquid crystal element, or a beam expander lens can be used.

  Finally, each block of the servo DSP 16, particularly the storage unit 401, the calculation unit 402, the calculation unit 412, and the total signal acquisition unit 413 may be configured by hardware logic, or software using the CPU as described below. It may be realized by.

  That is, the servo DSP 16 includes a CPU (central processing unit) that executes instructions of a control program that realizes each function, a ROM (read only memory) that stores the program, a RAM (random access memory) that expands the program, A storage device (recording medium) such as a memory for storing the program and various data is provided. An object of the present invention is to provide a recording medium in which a program code (execution format program, intermediate code program, source program) of a control program of the servo DSP 16 which is software for realizing the above-described functions is recorded so as to be readable by a computer. This can also be achieved by supplying the servo DSP 16 and reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU).

  Examples of the recording medium include tapes such as magnetic tapes and cassette tapes, magnetic disks such as floppy (registered trademark) disks / hard disks, and disks including optical disks such as CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  The servo DSP 16 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Further, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  As described above, the optical pickup control device, its program and recording medium, the optical disk device, and the optical pickup control method according to the present invention can reduce the time required to start the focus jump during the interlayer jump process. To. Therefore, the present invention can be suitably used in an industrial field related to an optical disc recording / reproducing apparatus such as a CD-ROM drive and a DVD-ROM drive, and equipment equipped with these optical disc recording / reproducing apparatuses.

It is a block diagram which shows the principal part structure of the optical disk recording / reproducing apparatus of this invention. It is a perspective view which shows the principal part structure of the optical pick-up in the said optical disk recording / reproducing apparatus. It is a block diagram which shows the structure regarding the focus servo and spherical aberration servo in the said optical disk recording / reproducing apparatus. It is a block diagram which shows the structure regarding the tracking servo in the said optical disk recording / reproducing apparatus. It is a functional block diagram of the servo controller in the said optical disk recording / reproducing apparatus. It is the figure which represented typically the change of the aberration error signal at the time of the interlayer jump in the said optical disk recording / reproducing apparatus. (A)-(c) is a figure showing the change of the various signals at the time of the interlayer jump in the said optical disk recording / reproducing apparatus. It is a figure showing the correlation between the position of the collimating lens and the gain ratio of the focus error signal in the optical disc recording / reproducing apparatus. 3 is a flowchart showing an operation flow in the optical disc recording / reproducing apparatus. 3 is a flowchart showing an operation flow in the optical disc recording / reproducing apparatus. It is a functional block diagram of the servo controller of the optical disk recording / reproducing apparatus in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 1a Optical disk 1b Optical disk 2 Objective lens (Condensing optical system)
4 Semiconductor laser (light source)
9 RF processing circuit 13 Actuator driver (focal position change means)
16 Servo DSP (optical pickup controller)
26 Collimating lens (Condensing optical system)
30 Optical disk recording / reproducing apparatus (optical disk apparatus)
32 Mirror (Condensing optical system)
40 Servo controller (operation control means)
41 Error signal generation circuit (spherical aberration detection means, focus error detection means)
42 Various compensation circuits for focus servo (focus follow-up means, focus jump drive means)
401 storage unit 402 calculation unit 412 calculation unit (spherical aberration correction means, threshold value correction means)
413 Total signal acquisition unit (correction signal acquisition means)
440 Servo controller (operation control means)

Claims (12)

A condensing optical system for condensing irradiation light from a light source on an optical disc having a plurality of recording layers, the condensing optical system comprising a collimating lens movable along the optical axis of the irradiation light;
In a control apparatus for an optical pickup comprising a focal position changing means for changing a focal position of the irradiation light by moving an objective lens of the condensing optical system,
Spherical aberration detection means for detecting spherical aberration generated in the condensing optical system as a spherical aberration signal;
Focus jump driving means for instructing the focus position changing means to drive so as to perform a focus jump for moving the focal position between recording layers of the optical disc;
Correction signal acquisition means for acquiring a correction signal for correcting the spherical aberration signal from the reflected light of the optical disc;
Spherical aberration signal correction means for correcting the spherical aberration signal based on the correction signal acquired by the correction signal acquisition means;
An operation control means for operating the focus jump drive means when the value of the spherical aberration signal corrected by the spherical aberration signal correction means has reached a predetermined threshold value ;
The predetermined threshold is a value of the spherical aberration signal at a predetermined time before reaching the value of the spherical aberration signal when the correction of the spherical aberration for the recording layer to which the focus jump is completed is completed. An optical pickup control device. A condensing optical system for condensing irradiation light from a light source on an optical disc having a plurality of recording layers, the condensing optical system comprising a collimating lens movable along the optical axis of the irradiation light;
In a control apparatus for an optical pickup comprising a focal position changing means for changing a focal position of the irradiation light by moving an objective lens of the condensing optical system,
Spherical aberration detection means for detecting spherical aberration generated in the condensing optical system as a spherical aberration signal;
Focus jump driving means for instructing the focus position changing means to drive so as to perform a focus jump for moving the focal position between recording layers of the optical disc;
Correction signal acquisition means for acquiring a correction signal for correcting a predetermined threshold value from the reflected light of the optical disc;
On the basis of the corrected signal obtained by correcting the signal acquisition means, and a threshold value correcting means for correcting the threshold value which is determined in advance,
An operation control means for operating the focus jump drive means when the value of the spherical aberration signal has reached the threshold value corrected by the threshold value correction means ,
The predetermined threshold value is a value of the spherical aberration signal at a predetermined time before reaching the value of the spherical aberration signal when the correction of the spherical aberration for the recording layer of the focus jump destination is completed. An optical pickup control device. Before SL operation control means, when with respect to the focus jump destination recording layer, the value of the spherical aberration signal corrected by the spherical aberration signal correction means reaches the threshold value, and wherein the actuating said focus jump drive means The control apparatus for an optical pickup according to claim 1. A focus error detecting means for detecting a shift between a focusing position of the condensing optical system and a focal point with respect to the recording layer as a focus error signal;
A focus follow-up means for causing the focus position to follow the focus based on the focus error signal;
The threshold value is in a range corresponding to a value of the spherical aberration signal at a time point when an amplitude value of the focus error signal is at a level at which the focus follower can be stably operated. Item 4. The optical pickup control device according to Item 3.   The threshold value is a value of the spherical aberration signal when the amplitude value of the focus error signal reaches a level at which the focus follower can be stably operated. Optical pickup control device.   The optical pickup control device according to claim 3, further comprising a storage unit that stores the threshold value.   4. The optical pickup according to claim 3, wherein the operation control unit operates the focus jump driving unit at a timing corresponding to each of the plurality of optical discs according to the threshold value corresponding to each of the plurality of optical discs. Control device.   The program which operates a computer as said each means with which the control apparatus of the optical pick-up of any one of Claims 1-7 is provided.   A computer-readable recording medium on which the program according to claim 8 is recorded. An optical pickup having a light source and a condensing optical system for condensing the irradiation light from the light source on the optical disc;
An optical disc device comprising: the optical pickup control device according to claim 1. A condensing optical system for condensing irradiation light from a light source on an optical disc having a plurality of recording layers, the condensing optical system comprising a collimating lens movable along the optical axis of the irradiation light;
In a control method of an optical pickup comprising a focal position changing unit that changes a focal position of the irradiation light by moving an objective lens of the condensing optical system,
A spherical aberration detection step of detecting spherical aberration generated in the condensing optical system as a spherical aberration signal;
A focus jump driving step of instructing the focus position changing means to drive so as to perform a focus jump that moves the focal position between recording layers of the optical disc;
A correction signal acquisition step of acquiring a correction signal for correcting the spherical aberration signal from the reflected light of the optical disc;
A spherical aberration signal correction step of correcting the spherical aberration signal based on the correction signal acquired in the correction signal acquisition step;
An operation control step of executing the focus jump driving step when the value of the spherical aberration signal corrected in the spherical aberration signal correction step reaches a predetermined threshold value ,
The predetermined threshold is a value of the spherical aberration signal at a predetermined time before reaching the value of the spherical aberration signal when the correction of the spherical aberration for the recording layer to which the focus jump is completed is completed. And a method for controlling the optical pickup. A condensing optical system for condensing irradiation light from a light source on an optical disc having a plurality of recording layers, the condensing optical system comprising a collimating lens movable along the optical axis of the irradiation light;
In a control method of an optical pickup comprising a focal position changing unit that changes a focal position of the irradiation light by moving an objective lens of the condensing optical system,
A spherical aberration detection step of detecting spherical aberration generated in the condensing optical system as a spherical aberration signal;
A focus jump driving step of instructing the focus position changing means to drive so as to perform a focus jump that moves the focal position between recording layers of the optical disc;
A correction signal acquisition step of acquiring a correction signal for correcting a predetermined threshold value from the reflected light of the optical disc;
On the basis of the correction signal obtained in the correction signal acquiring step, the threshold value correcting step of correcting the threshold value which is determined in advance,
An operation control step of executing the focus jump drive step when the value of the spherical aberration signal has reached the threshold value corrected in the threshold value correction step,
The predetermined threshold value is a value of the spherical aberration signal at a predetermined time before reaching the value of the spherical aberration signal when the correction of the spherical aberration for the recording layer of the focus jump destination is completed. A method for controlling an optical pickup.

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