JP2011129174A - Optical disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To promptly determine whether a focal position to a multilayer optical disk is located on a target layer. <P>SOLUTION: When a controller 24 performs setting of a focal position of an optical pickup 16 in a target layer of any one of recording layers L0 to L3 of the multilayer optical disk 28 and adjusts the focal position of the optical pickup 16, according to the setting, the controller has a laser beam from the optical pickup 16 irradiated to the multilayer optical disk 28, and compares an amplitude change amount of an electrical signal generated from the reflected beam thereof by a signal generating circuit 18 and a determined value of a memory and determines whether the focal position of the optical pickup 16 is located on the target layer, based on the comparison result. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus, and more particularly, to a technique for determining whether or not a focal position with respect to a multilayer optical disc has deviated.

  Some optical discs have a plurality of information recording films, such as DVD (Digital Versatile Disc), HD (Hard Disk) -DVD, and Blu-ray Disc. Currently, DVD and Blu-ray discs have two-layer optical discs, and HD-DVD has three-layer optical discs. In the future, Blu-ray discs and other discs will have four or more layers.

At this time, with the increase in the number of optical disks, a focus servo control system technique for condensing laser light on the information recording surface of the optical disk becomes important. For this reason, various techniques have been proposed for rapidly moving the focal position of laser light to the target layer.

  For example, Patent Document 1 discloses a method of analyzing a focus error signal output pattern when controlling a focus servo system for a two-layer optical disc and determining whether or not the focus servo system is disconnected based on the analysis result. Adopted.

JP 2006-127616 A

  By the way, in the case of a multi-layer optical disk having three layers or four or more layers as the optical disk, the distance between layers (layer spacing) is small, for example, when the focal position positioned in a certain layer of the multilayer is removed by impact, The focal position may move to another layer. If the process is executed as it is without determining whether the focal position is positioned on the target layer, the process is performed with the focal position shifted, and the reading process and the writing process on the target layer are accurately performed. become unable.

On the other hand, when determining whether or not the focal position deviates from the target layer due to an impact or the like, in the case of a three-layer optical disc, the focal position is adjusted to the target layer by performing three processes for adjusting the focal position. In the case of a four-layer optical disc, it is possible to determine whether or not the focal position is on the target layer by performing four processes for adjusting the focal position. .

  However, in consideration of the fact that the focal position may deviate from the target layer due to an impact or the like, in order to determine whether or not the focal position is in the target layer, three or four processes are executed. A lot of time is required for the process for determination, and the process cannot be performed quickly.

  The present invention has been made in view of the above-described problems of the prior art, and an object thereof is to provide an optical disc apparatus capable of quickly determining whether or not a focal position with respect to a multilayer optical disc is in a target layer. It is in.

  In order to achieve the above object, the present invention irradiates a multilayer optical disk with laser light from a laser light source via an objective lens, and receives reflected light from the multilayer optical disk, and receives light from the optical pickup. A signal generation circuit for generating an electrical signal from the reflected light of the optical pickup, an actuator for adjusting a tilt angle and a focal position of the optical pickup, a memory for storing a determination value of each recording layer, and an electric circuit for generating the signal generation circuit A controller for controlling the driving of the actuator based on a signal, the controller using any one of the recording layers of the multilayer optical disc as a target layer, and the focal position of the optical pickup on the target layer And generating the signal generation circuit when controlling the driving of the actuator according to the setting. According compared with the amplitude variation of the electrical signal and the determined value of the memory, the focal position of the optical pickup based on the comparison result, characterized by comprising determining whether the target layer.

  According to the present invention, it is possible to quickly determine whether or not the focus position of the optical pickup is in the target layer, and the reproduction / recording operation can be performed quickly and accurately.

1 is a block diagram of an optical disc apparatus showing an embodiment of the present invention. It is a front view of an optical pick-up. It is a figure for demonstrating the operation | movement which changes the tilt angle of an optical pick-up. It is a section lineblock diagram of a multilayer optical disk. FIG. 6 is a characteristic diagram illustrating a relationship between a tilt angle and a signal amplitude change amount. 5 is a flowchart for explaining processing of the optical disc device.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of an optical disc showing an embodiment of the present invention. In FIG. 1, an optical disk apparatus 10 includes a disk motor 12, a disk drive circuit 14, an optical pickup 16, a signal generation circuit 18, a pickup drive circuit 20, a control circuit 22, and a controller 24. A multilayer optical disk 28 is rotatably mounted on the rotating shaft 26 of the disk motor 12.

  The disk motor 12 is composed of, for example, a spindle motor, and the rotation speed and rotation frequency thereof are controlled by the disk drive circuit 14.

  The optical pickup 16 includes, for example, a laser light source, a beam splitter, an objective lens, a photodetector, and the like (all not shown), and laser light from the laser light source is applied to the multilayer optical disk 28 via the beam splitter and the objective lens. The reflected light reflected from one of the recording layers (information recording layers) of the multilayer optical disk 28 is received, and the received light is detected by a photodetector through an objective lens and a beam splitter, and light detection is performed. The detection signal generated by the detector is output to the signal generation circuit 18.

  At this time, the optical pickup 16 adjusts the focal position of the optical pickup 16, the tracking of the optical pickup 16, and the tilt angle of the optical pickup 16 according to three types of signals from the pickup driving circuit 20.

  When adjusting the tilt angle of the optical pickup 16, as shown in FIG. 2, the optical pickup 16 includes electromagnetic coils 30 and 32, and the electromagnetic coils 30 and 32 are provided in a lens holder 36 that houses the objective lens 34. It is arranged around. Support tools 38 and 40 are fixed to both ends of the lens holder 36 in the horizontal direction, and the support tools 38 and 40 are connected to the base 46 via elastic connecting members 42 and 44.

  As shown in FIG. 3, the optical pickup 16 is arranged so that the center line of the lens holder 36 and the surface of the multilayer optical disk 28 are parallel when the tilt angle with respect to the optical pickup 16 is zero.

  On the other hand, when a positive voltage is applied to the electromagnetic coils 30 and 32, for example, from the pickup drive circuit 20, the tilt angle changes counterclockwise according to the magnitude of the applied voltage. When a negative voltage is applied to 32, the tilt angle changes clockwise according to the magnitude of the applied voltage.

  On the other hand, the signal generation circuit 18 takes in a detection signal from a photodetector built in the optical pickup 16 and generates a high-frequency reproduction signal (hereinafter referred to as an RF signal) as an electrical signal from the reflected light received by the optical pickup 16. A push pull signal is generated, and the generated RF signal and push pull signal are output to the controller 24.

  The controller 24 is composed of, for example, a microcomputer including a CPU (Central Processing Unit), a ROM (Read Only Memory), an input / output interface, a memory, and the like. The CPU executes various arithmetic processes according to the processing program stored in the ROM.

  For example, the controller 24 uses any one of the recording layers of the multilayer optical disc 28 as a target layer based on the RF signal and push-pull signal generated by the signal generation circuit 18, and the focal position of the optical pickup 16 on the target layer. When the driving of the actuator is controlled according to this setting, the RF signal or push-pull signal is compared with the determination value stored in the memory, and the focal position of the optical pickup 16 is determined based on the comparison result. It is determined whether or not the target layer is present.

  The controller 24 also outputs a command for controlling the focal position of the optical pickup 16, a command for controlling the tracking of the optical pickup 16, and a command for adjusting the tilt angle of the optical pickup 16 to the control circuit 22. To do.

  The control circuit 22 controls a control signal for adjusting the focal position of the optical pickup 16, a control signal for controlling tracking of the optical pickup 16, or a tilt angle of the optical pickup 16 based on a command from the controller 24. Control signals are generated, and the generated control signals are output to the pickup drive circuit 20.

  The pickup driving circuit 20 adjusts the focal position of the optical pickup 16 according to the control signal generated by the control circuit 22, adjusts tracking, and further adjusts the tilt angle of the optical pickup 16. At this time, the pickup driving circuit 20 and the control circuit 22 are configured as actuators for adjusting the focal position, tracking, and tilt angle of the optical pickup 16.

  Here, when the controller 24 stores the determination value of each recording layer in the memory, as shown in FIG. 4, the multi-layer optical disk 28 has four recording layers L0, L1, L2, and L3 (the recording layer L0 has When the recording layer L3 is the layer farthest from the surface on which the laser light from the optical pickup 16 is incident and the recording layer L3 is the layer closest to the surface on which the laser light from the optical pickup 16 is incident), When the tilt angle of the optical pickup 16 is changed while the focal position is set to each of the recording layers L0, L1, L2, and L3 of the multilayer optical disk 28, the signal generation circuit 18 The amount of change in the amplitude of the electrical signal due to the generation is stored as a judgment value for each recording layer L0, L1, L2, L3.

Specifically, as shown in FIG. 5, the tilt angle (tilt tilt angle) of the optical pickup 16 is set in a state where the focal position of the optical pickup 16 is set to each of the recording layers L0, L1, L2, and L3 of the multilayer optical disc 28. ) Is changed from 0.00 to 0.30, the amplitude change amount (signal amplitude change amount) of the RF signal or push-pull signal is approximately 1.00 as indicated by the characteristics 100, 101, 102, 103. It changes in the range of ~ 0.10.

  That is, when the tilt angle of the optical pickup 16 is changed from 0.00 to 0.30 in a state where the focal position of the optical pickup 16 is set to the recording layer L0 of the multilayer optical disk 28, the signal amplitude change amount is a characteristic. Along the line 100, it will change in the range of about 1.00 to 0.10. In other words, when the signal amplitude change amount when the tilt angle of the optical pickup 16 is changed from 0.00 to 0.30 shows a value on the characteristic 100, the focal position of the optical pickup 16 is recorded on the multilayer optical disk 28. It will be in layer L0. For this reason, the signal amplitude change amount corresponding to the characteristic 100 is used as a determination value for determining whether or not the focal position of the optical pickup 16 is in the recording layer L0 of the multilayer optical disk 28.

  Similarly, when the focus angle of the optical pickup 16 is set to the recording layers L1 to L3 of the multilayer optical disk 28, and the tilt angle of the optical pickup 16 is changed from 0.00 to 0.30, the signal amplitude changes. The amount will vary in the range of approximately 1.00 to 0.40 along the characteristics 101-103. In other words, when the signal amplitude change amount when the tilt angle of the optical pickup 16 is changed from 0.00 to 0.30 shows a value on the characteristics 101 to 103, the focal position of the optical pickup 16 is the multilayer optical disk 28. The recording layers L1 to L3. For this reason, the signal amplitude change amount corresponding to the characteristics 101 to 103 is used as a determination value for determining whether or not the focal position of the optical pickup 16 is in the recording layers L1 to L3 of the multilayer optical disk 28.

The characteristic 100 is that the tilt angle (tilt tilt angle) of the optical pickup 16 is changed from 0.00 to 0.30 in a state where the focal position of the optical pickup 16 is set to the recording layer L0 of the multilayer optical disk 28. It's time. A characteristic 101 is obtained when the tilt angle of the optical pickup 16 is changed from 0.00 to 0.30 in a state where the focal position of the optical pickup 16 is set to the recording layer L1 of the multilayer optical disk 28. A characteristic 102 is obtained when the tilt angle of the optical pickup 16 is changed from 0.00 to 0.30 in a state where the focal position of the optical pickup 16 is set to the recording layer L2. Characteristic 103 is obtained when the tilt angle of the optical pickup 16 is changed from 0.00 to 0.30 in a state where the focal position of the optical pickup 16 is set to the recording layer L3 of the multilayer optical disk 28.

  Next, processing of the optical disc apparatus will be described with reference to the flowchart of FIG. First, when the process starts, the controller 24 drives the pickup drive circuit 20 as a process for changing the tilt angle of the optical pickup 16 as a pre-learning process (S1).

  Next, the controller 24 sequentially performs processing for adjusting the focal position of the optical pickup 16 on each of the recording layers L0, L1, L2, and L3, and sets the focal position of the optical pickup 16 to the recording layers L0, L1, and L2. , L3, the RF signal or push-pull signal is taken in as an electrical signal from the signal generation circuit 18 and the change amount (amplitude change amount) of the RF signal or push-pull signal is measured (S2). Is stored in the memory (S3). That is, as shown in FIG. 5, the measurement results according to the characteristics 100, 101, 102, and 103 are stored in the memory as the change amount (amplitude change amount) of the RF signal or push-pull signal.

  When it is detected that the multilayer optical disc 28 has been inserted after the pre-learning process is completed (S4), the controller 24 receives a reproduction / recording operation instruction based on the reflected light from the multilayer optical disc 28 (S5), and the target Processing for adjusting the focal position on the layer is executed (S6).

  At this time, the focal position of the optical pickup 16 with respect to the multilayer optical disk 28 may be out of the target layer due to an impact or the like (S7).

  Next, the controller 24 takes into consideration that the focal position of the optical pickup 16 with respect to the multilayer optical disk 28 is shifted from the target layer to another layer due to impact on the multilayer optical disk 28 or surface vibration of the multilayer optical disk 28. As a process for changing the tilt angle, the pickup drive circuit 20 is driven (S8).

For example, the controller 24 executes processing for changing the tilt angle of the optical pickup 16 by 0.30, and in this state, acquires the RF signal or push-pull signal from the signal generation circuit 18 (S9), and acquires the acquired signal. From the change amount (amplitude change amount), the recording layer to be the focal position of the optical pickup 16 is determined (S10).

For example, when the controller 24 changes the tilt angle of the pickup 16 by 0.30 and the signal amplitude change amount is smaller than 0.20, the focus position of the optical pickup 16 is determined from the characteristic 100 of FIG. It is determined that the recording layer is L0.

  Next, the controller 24 compares the amplitude change amount of the acquired signal with the determination value (memory value) of the memory (S11), and determines whether or not the focal position of the optical pickup 16 is in the target layer (S12). ).

For example, when the target layer is the recording layer L1, the amplitude change amount of the signal when the tilt angle is 0.30 is approximately 0.40 from the characteristic 101 in FIG. On the other hand, when the amplitude change amount of the acquired signal is smaller than 0.20, the focal position of the optical pickup 16 is in the recording layer L0 from the characteristic 100 of FIG. In this case, assuming that the focal position has shifted from the recording layer L1 of the target layer to the recording layer L0, a process for positioning the focal position on the target layer is performed (S13). Thereafter, the process returns to step S8 again, and the processes from step S8 to step S12 are repeated.

  On the other hand, when the amplitude change amount of the acquired signal coincides with the determination value stored in the memory in step S12, it is assumed that the focal position of the optical pickup 16 is in the recording layer L1 of the target layer. Processing for continuing the operation is performed (S14), and the processing in this routine is terminated.

  As described above, in this embodiment, any one of the recording layers L0, L1, L2, and L3 of the multilayer optical disk 28 is set as a target layer, and the focal position of the optical pickup 16 is set in the target layer. In the process of controlling the driving of the pickup drive circuit 20 according to the setting, the amplitude change amount of the RF signal or push-pull signal generated by the signal generation circuit 18 is compared with the determination value stored in the memory, and based on this comparison result Since it is determined whether or not the focal position of the optical pickup 16 is in the target layer, it is possible to quickly determine whether or not the focal position of the optical pickup 16 is in the target layer, and the reproduction / recording operation can be quickly performed. And accurately.

  Further, in the present embodiment, a description has been given of using an electric signal when the tilt angle of the optical pickup 16 is changed as an electric signal for comparison with a determination value of the memory (determination value stored in the memory). However, when the multilayer optical disk 28 has a surface shake and is in a state equivalent to when the tilt angle of the optical pickup 16 is changed, the electrical signal at that time is RF without changing the tilt angle of the optical pickup 16. Signals or push-pull signals can also be used.

  Further, at least one of an RF signal and a push-pull signal can be used as an electrical signal for comparison with the determination value of the memory. When the multilayer optical disc 28 is a multilayer optical disc in which information has been recorded, an RF signal or a push-pull signal can be used as an electrical signal for comparison with the determination value of the memory, and the multilayer optical disc 28 has recorded information. When the optical disc is not a multi-layer optical disc, a push-pull signal can be used as an electrical signal for comparison with the determination value of the memory.

  10 optical disk device, 12 disk motor, 14 disk drive circuit, 16 optical pickup, 18 signal generation circuit, 20 pickup drive circuit, 22 control circuit, 24 controller, 28 multilayer optical disk, 30, 32 electromagnetic coil, 34 objective lens,

Claims (5)

An optical pickup that irradiates a multilayer optical disc with laser light from a laser light source via an objective lens, and receives an reflected light from the multilayer optical disc, and a signal generation circuit that generates an electrical signal from the reflected light by the reception of the optical pickup And an actuator that adjusts the tilt angle and focal position of the optical pickup, and the tilt angle of the optical pickup is changed in a state where the focal position of the optical pickup is set in each recording layer of the multilayer optical disc, Based on the electrical signal generated by the signal generation circuit and a memory that stores the amplitude change amount of the electrical signal generated by the signal generation circuit according to the change of the tilt angle as a determination value of each recording layer. A controller for controlling the drive of the actuator,
The controller sets any one of the recording layers of the multilayer optical disc as a target layer, sets the focal position of the optical pickup on the target layer, and controls the driving of the actuator according to the setting. The amplitude change amount of the electric signal generated by the signal generation circuit is compared with the determination value of the memory, and it is determined whether or not the focus position of the optical pickup is in the target layer based on the comparison result. Optical disk device. The controller receives, as an electric signal for comparison with the determination value of the memory, an electric signal when the tilt angle of the optical pickup is changed by controlling the driving of the actuator from the signal generation circuit. The optical disc apparatus according to claim 1. The signal generation circuit generates a high frequency reproduction signal or a push-pull signal as the electrical signal,
The controller inputs at least one of a high-frequency reproduction signal or a push-pull signal generated by the signal generation circuit from the signal generation circuit as an electrical signal for comparison with a determination value of the memory. Item 4. The optical disk device according to Item 1. The signal generation circuit generates a high frequency reproduction signal or a push-pull signal as the electrical signal,
The controller, when the multilayer optical disc is a multilayer optical disc in which information has been recorded, as a high-frequency reproduction signal or push-pull signal generated by the signal generation circuit, as an electrical signal for comparison with the determination value of the memory, The optical disk apparatus according to claim 1, wherein the optical disk apparatus is input from the signal generation circuit. The signal generation circuit generates a high frequency reproduction signal or a push-pull signal as the electrical signal,
When the multilayer optical disk is a multilayer optical disk on which information has not been recorded, the controller generates a push-pull signal generated by the signal generation circuit as an electric signal for comparison with a determination value of the memory. The optical disk apparatus according to claim 1, wherein the optical disk apparatus is input from