JP2007317298A - Device, method and program for playing optical disk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a disk for playing an optical disk, capable of turning on a tracking servo without changing a hardware configuration. <P>SOLUTION: This device is provided with a photodetection circuit 16A for generating a focus error signal and a tracking error signal based on detection signal detected by a photodetector 16, a control unit 26 for measuring the amplitude of the tracking error signal generated by the photodetector 16A, a control unit 26 for determining whether a disk is an optical disk 11 to be turned ON by the tracking servo based on the measured amplitude of the tracking error signal, and a control unit 26 for changing the offset value of focus balance to drive an actuator 22 so as to turn ON the focus servo and the tracking servo when the control unit 26 judges that the disk is not an optical disk to be turned ON by the tracking servo. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical disc playback apparatus, an optical disc playback method, and an optical disc playback program.

  2. Description of the Related Art Conventionally, there are known optical disc reproducing apparatuses that record data on an optical information storage medium such as a DVD (Digital Versatile Disc) or a CD (Compact Disc), or reproduce the recorded data. The optical disk reproducing apparatus reflects the light beam emitted from the light source by a prism or the like and guides it to the objective lens. Then, light is condensed from the objective lens onto an information recording surface of an optical information storage medium (hereinafter referred to as an optical disk), and the reflected light is received by a photodetector. As a result, data can be reproduced or recorded on the optical disc.

  Among optical discs, there is a disc called a dual disc. Here, the dual disc refers to a double-sided disc in which video and audio signals conforming to the DVD standard are recorded on one side of the disc and audio signals dedicated to music are recorded on the other side. The dual disc has a signal recording layer in which an audio signal dedicated to surface music of the disc is recorded at 0.9 mm.

A tracking control method using a three-beam method is known as a method for controlling the track of an optical disk. (For example, refer to Patent Document 1).
JP-A-10-334501

In the case of a CD, the signal recording layer is located 1.2 mm from the surface of the disk. Therefore, in the above prior art, the tracking servo cannot be turned on for a disk in which a signal recording layer such as a dual disk is located 0.9 mm from the surface of the disk. That is, when the tracking error signal is generated by the three sub-beams, the tracking error signal cannot be detected because the track (pit end) does not work well in the three sub-beam portions at the focus ON position.
In this case, as a method of reproducing the disc, there is a method of changing the NA of the lens or the position of the light receiving element of the pickup. However, if the lens NA or the position of the light receiving element of the pickup is changed, the hardware configuration must be changed.
Therefore, there has been a demand for realizing an optical disk reproducing apparatus capable of turning on the tracking servo of an optical disk such as a dual disk without changing the hardware configuration.

Accordingly, an object of the present invention is to realize an optical disk reproducing apparatus that can turn on a tracking servo without changing the hardware configuration.

In order to solve the above-described problem, an optical disk reproducing apparatus according to the first aspect of the present invention provides:
A light source, an objective lens for condensing the light beam emitted from the light source on the recording surface of the optical disc, and a photodetector for receiving the light beam reflected from the recording surface of the optical disc and outputting a detection signal corresponding to the received light amount With an optical pickup,
First driving means for moving the optical pickup in a radial direction of the optical disc;
A second driving means for moving the objective lens in a radial direction of the optical disc and moving the objective lens in a direction substantially perpendicular to a recording surface of the optical disc;
Generating means for generating a focus error signal and a tracking error signal based on a detection signal detected by the photodetector;
First measuring means for measuring the amplitude of the tracking error signal generated by the generating means;
First discriminating means for discriminating whether or not the optical disc is capable of turning on tracking servo based on the amplitude of the tracking error signal measured by the first measuring unit;
Control means for driving the second drive means so as to change the focus balance offset value and turn on the focus servo and tracking servo when the first determination means determines that the optical disk cannot be turned on by tracking servo; ,
It is characterized by providing.

According to a second aspect of the present invention, there is provided the optical disc reproducing apparatus according to the first aspect,
The control means includes
A second measuring means for further measuring the amplitude of the tracking error signal when the offset value of the focus balance is changed;
A second discriminating unit that discriminates whether or not the amplitude of the tracking error signal measured by the second measuring unit is a detection level at which the tracking servo can be turned on;
When it is determined by the second determination means that the amplitude of the tracking error signal is smaller than a detection level at which the tracking servo can be turned on, the offset value of the focus balance is further changed and the second servo is turned on. And the second discriminating unit again discriminates the amplitude of the tracking error signal generated by the generating unit, while the second discriminating unit determines the amplitude of the tracking error signal by the tracking servo. When it is determined that the detection level is greater than the detection level that can be turned on, the second drive unit is driven so as to turn on the focus servo and tracking servo.

According to a third aspect of the present invention, there is provided the optical disk reproducing apparatus according to the second aspect,
The control means includes
A third determining means for determining the number of changes in the offset value of the focus balance;
When the number of changes of the focus balance offset value exceeds a predetermined number by the third determining means, it is determined that the optical disk cannot be reproduced.

An optical disk reproducing method according to a fourth aspect of the present invention comprises:
A light source, an objective lens for condensing the light beam emitted from the light source on the recording surface of the optical disc, and a photodetector for receiving the light beam reflected from the recording surface of the optical disc and outputting a detection signal corresponding to the received light amount An optical pickup; first driving means for moving the optical pickup in a radial direction of the optical disc; and moving the objective lens in a radial direction of the optical disc, and moving the objective lens substantially perpendicular to a recording surface of the optical disc. In an optical disc reproducing method of an optical disc reproducing apparatus, comprising: a second driving unit that moves in a direction; and a generating unit that generates a focus error signal and a tracking error signal based on a detection signal detected by the photodetector.
A measuring step of measuring the amplitude of the tracking error signal generated by the generating means by a measuring means;
A determination step of determining by a determination means whether or not the optical disk is capable of turning on tracking servo based on the amplitude of the tracking error signal measured in the first measurement step;
A control step of driving the second drive means by the control means so as to change the focus balance offset value and turn on the focus servo and tracking servo when the discriminating process determines that the optical disk cannot be turned on by the tracking servo. ,
It is characterized by including.

An optical disk reproduction program according to the invention of claim 5 is provided.
Computer
Measuring means for measuring the amplitude of the tracking error signal;
Discriminating means for discriminating whether or not the optical disk can be turned on by tracking servo based on the amplitude of the tracking error signal measured by the measuring means;
When the discriminating unit discriminates that the optical disc cannot be turned on, the objective lens is moved in the radial direction of the optical disc so as to change the focus balance offset value and turn on the focus servo and the tracking servo. Control means for driving a drive means for moving the objective lens in a direction substantially perpendicular to the recording surface of the optical disc;
It is made to function as.

  According to the present invention, it is possible to realize an optical disk reproducing apparatus that can turn on the tracking servo without changing the hardware configuration.

  Embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. However, the scope of the invention is not limited to the illustrated examples.

  The embodiment according to the present invention will be described with reference to FIGS. FIG. 1 illustrates the apparatus configuration of an optical disk reproducing apparatus 1 according to the present invention. FIG. 2 shows a generation image of the tracking error signal. FIG. 3 shows the flow of the CD media determination process. FIG. 4 shows the flow of the focus balance control process.

  First, the device configuration of the optical disk playback device 1 will be described. As shown in FIG. 1, the optical disc playback apparatus 1 sequentially reads and plays back video data, audio data, and the like recorded on an optical disc 11. Specifically, it is a device that is driven by a commercial power source, a battery power source, or the like to reproduce or record video data or music data, and can be installed stationary, carried, mounted on the vehicle, or the like.

  The optical disk reproducing apparatus 1 includes a spindle motor 12, a spindle driver 13, an optical pickup 14, an objective lens 15, a photodetector 16, a light detection circuit 16A as detection means, a light source 17, and a feed motor 18 as first drive means. A tracking driver 19, an RF (Radio Frequency) amplifier 20, a focus driver 21, an actuator 22 as a second driving means, a digital signal processing circuit 23, a first discriminating means, a second discriminating means, a third discriminating means, The first measurement unit, the second measurement unit, a control unit 26 as a control unit, an operation unit 27, a display unit 28, a time measuring unit 29, a storage unit 30, and a disk transport unit 31 are configured.

  The optical disk 11 is a CD, a CD-R / RW (Recordable / ReWriteable), a DVD, a DVD-R / RW, or the like.

  The spindle motor 12 is controlled by the digital signal processing circuit 23 to rotate the optical disk 11 held by a turntable or a clamp mechanism (not shown) at a predetermined rotational speed. The spindle driver 13 outputs a drive signal corresponding to a control signal based on an instruction from the CPU in the control unit 26 to the spindle motor 12 to drive the spindle motor 12.

  The optical pickup 14 irradiates the optical disk 11 with laser light under the control of the digital signal processing circuit 23 to enable reproduction of video data, audio data, and the like (hereinafter, video data, audio data, etc. are used as data). belongs to.

The optical pickup 14 outputs the detected data signal to the RF amplifier 20. The objective lens 15 condenses the light beam emitted from the light source 17 on the recording surface of the optical disk 11 and condenses the reflected light beam reflected from the recording surface of the optical disk 11. The photodetector 16 receives the reflected light beam collected by the objective lens 15 and converts it into an electrical signal corresponding to the reflected light beam. The photodetection circuit 16A generates a tracking error signal (TE signal) and a focus error signal (FE signal) based on the detection signal detected by the photodetector 16.

The light source 17 is a semiconductor laser diode that generates laser light. The semiconductor laser diode includes a CD laser diode and a DVD laser diode having different wavelengths.

  The feed motor 18 moves the optical pickup 14 in the radial direction of the optical disc 11 under the control of the digital signal processing circuit 23. The tracking driver 19 outputs a drive signal corresponding to a control signal based on an instruction from the CPU in the control unit 26 to the actuator 22 to drive the actuator 22.

  The RF amplifier 20 amplifies the TE signal, the FE signal, and the like. The RF amplifier 20 outputs various amplified signals to the digital signal processing circuit 23.

The focus driver 21 outputs a drive signal corresponding to a control signal based on an instruction from the CPU in the control unit 26 to the actuator 22 to drive the actuator 22. The actuator 22 moves the objective lens 15 in a direction perpendicular to the recording surface of the optical disc 11 (hereinafter referred to as a focus direction) to adjust the focus of the light beam condensed on the recording surface of the optical disc 11. The actuator 22 moves the objective lens 15 in the radial direction of the optical disc 11 in accordance with the drive signal output from the tracking driver 19.

  The digital signal processing circuit 23 is a signal processing circuit controlled by the control unit 26. The digital signal processing circuit 23 outputs drive control signals to the spindle driver 13, tracking driver 19, RF amplifier 20, and focus driver 21 based on the signal amplified by the RF amplifier 20. The digital signal processing circuit 23 detects address information ID, an RF signal, and the like on the recording surface of the optical disc 11 based on the electrical signal input from the RF amplifier 20.

  The control unit 26 includes a microprocessor and the like, and controls the digital signal processing circuit 23, the operation unit 27, the display unit 28, the time measuring unit 29, the storage unit 30, and the disk transport unit 31, thereby operating the optical disc playback apparatus 1. Central control. Although not particularly illustrated, the control unit 26 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and the like.

The control unit 26 reads a program specified from the system program and various application programs stored in the ROM and data stored in the storage unit 30, expands the data in the RAM, and expands the program and data expanded in the RAM. Various processes are executed in cooperation with the CPU. In particular, the ROM stores a CD media determination program described later.

The control unit 26 performs media discrimination of the optical disc 11 (CD) based on the TE signal by the CD media discrimination program. Further, the control unit 26 changes the setting value of the focus balance based on the TE signal.

  The operation unit 27 includes an operation panel having various keys such as a stop key, a reproduction key, a fast-rewind key, a fast-forward key, and a disc ejection key. The operation unit 27 reproduces / records audio data instructed by a user's operation input. Instruction information such as start or stop and ejection of the optical disk 11 is output to the control unit 26.

  The display unit 28 includes an LCD (Liquid Crystal Display) panel, an FPD (Flat Panel Display) using an organic EL (Electro Luminescence) element, an LED (Light Emitting Diode), and the like. Displays information about the operating status and various settings such as recording time, track number, and volume.

  The timer unit 29 is a circuit that measures the actual time under the control of the control unit 26 with reference to a clock signal from a crystal oscillator that constantly transmits a constant frequency, not shown, and outputs the measured time information to the control unit 26. Part.

  The storage unit 30 is a non-volatile memory in which data can be electrically rewritten, and stores various types of information.

  The disk transport unit 31 is a movable tray or the like that transports the optical disk 11 held in the apparatus by a turntable, a clamp mechanism, or the like by a drive mechanism such as a spindle motor under the control of the control unit 26. Can be easily removed. The disk transport unit 31 is not limited to the above-described configuration as long as the optical disk 11 can be removed. For example, the disk transport unit 31 is a lid and a mechanism for opening and closing the lid, and is held in the apparatus. The optical disk 11 may be removable.

  Next, a method for generating a tracking error signal (TE signal) will be described with reference to FIG. FIG. 2A is a diagram showing a TE signal generation image of the photodetector when the focus is normally turned on to a 1.2 mm thick layer. Here, “focus ON” means that the focal position of the light beam on the optical axis coincides with the layer on the recording surface of the optical disc. In this case, the focal position of the light beam on the optical axis coincides with the 1.2 mm thick layer. FIG. 2A shows that the light receiving surface of the photodetector 16 is divided into three parts of 16X, 16Y, and 16Z. Further, it shows that the main spot when the focus is turned on is irradiated on the light receiving surface 16X.

Here, generation of a focus error signal (FE signal) will be described. The FE signal is generated based on signals obtained from the areas A, B, C, and D of the light receiving surface 16X. In the case of FIG. 2A, the FE signal = (A + C) − (B + D).
Next, generation of the TE signal will be described. The TE signal is generated by the light detection circuit 16A based on signals obtained from the areas E and F of the light receiving surfaces 16Y and 16Z. In the case of FIG. 2A, TE signal = EF.

  In the example of FIG. 2A, the pit end where the signal is read is applied to the areas E and F. Therefore, the TE signal can be generated. Here, the pit for signal reading refers to a dent on the optical disk. A change occurs in the reflected light of the laser light depending on the presence or absence of the depression, and data is read by detecting the change in the reflected light. Therefore, if the pit end where the signal is read covers the areas E and F of the light receiving surfaces 16Y and 16Z, the TE signal can be generated.

  FIG. 2B is a diagram showing a TE signal generation image of the photodetector when the focus is normally turned on to a 0.9 mm thick layer. In this case, the signal-reading pit end does not cover the areas E and F of the light receiving surfaces 16Y and 16Z. Therefore, since a signal having the same phase is output from the regions E and F, a tracking error signal cannot be generated.

  FIG. 2C shows a generation image of the TE signal when the focus is turned on in a state where the light flux is out of focus on the 0.9 mm thick layer. This state is realized by breaking the focus balance. Here, the focus balance refers to the balance between the (A + C) signal of the FE signal and the (B + D) signal of the FE signal. The loss of focus balance refers to shifting the focus ON point by giving an offset to either the (A + C) signal of the FE signal or the (B + D) signal of the FE signal. In the example of FIG. 2C, since the focus is turned on in a state in which the light beam is out of focus in the 0.9 mm thick layer, the signal-reading pit ends are in the areas E and F of the light receiving surfaces 16Y and 16Z. Take it. Therefore, the TE signal can be generated.

  Next, the operation of the optical disc playback apparatus 1 according to the present embodiment will be described with reference to FIGS. First, with reference to FIG. 3, the flow of the CD media determination process executed by the optical disc playback apparatus 1 will be described. In the CD media discrimination processing, it is discriminated whether the CD signal recording layer is a CD located 1.2 mm from the surface of the optical disc 11 or the signal recording layer is a CD located 0.9 mm from the surface of the optical disc 11. It is processing to do.

  Assume that it is determined in advance that the medium type is CD by the process of determining the medium type of the optical disc 11. Here, the process of determining the medium of the optical disk 11 refers to a process of determining whether the optical disk 11 is a CD or a DVD. In this embodiment, it is assumed that the optical disk 11 is determined as a CD. In addition, it is assumed that the TE signal is generated by the three beam method.

  For example, in the optical disc playback apparatus 1, a CD media discrimination program that is read from the ROM and appropriately expanded in the RAM triggered by an input of an execution instruction of the CD media discrimination process from the user via the operation unit 27, etc. The CD media discrimination process is executed in cooperation with the CPU.

  First, the spindle servo is set to the CAV mode (step S101). Here, setting the spindle servo to the CAV mode means that the optical disk 11 is rotated at a constant speed by setting the spindle mode of the spindle motor 12. Then, the signal path is changed to the setting for CD. Here, changing the signal path to the CD setting means changing various signal processing settings to the CD. For example, various signal processing settings are set to the 3-beam mode. At the same time as the signal path is changed to the setting for CD, the CD laser is turned on (step S102).

  Then, the focus servo is turned on (step S103). When the focus servo is turned on, a PP (Peak to Peak) value of the amplitude of the TE signal is measured (step S104). And it is discriminate | determined whether PP value of the amplitude of the measured TE signal is smaller than a fixed value (step S105). Here, the constant value means a threshold value of the amplitude value of the TE signal at which the tracking servo can be turned on. When the PP value of the amplitude of the TE signal is smaller than a certain value (step S105; YES), the optical disc 11 is a CD whose signal recording layer is 0.9 mm from the surface of the optical disc 11 (that is, the optical disc 11 in which the tracking servo cannot be turned on). ). If it is determined from the surface of the optical disc 11 that the signal recording layer is a 0.9 mm CD, a focus balance control process is performed (step S106). The focus balance control process will be described later.

  After execution of step S106, the spindle servo is set to the rough sub mode (step S107). Here, setting the spindle servo to the rough sub mode means changing the setting mode of the spindle servo to the rough sub mode. Then, the tracking servo is turned on (step S108).

  After execution of step S108, gain adjustment of the focus servo and tracking servo is performed (step S109). Here, gain adjustment means adjusting the amplification degree of the RF amplifier 20. The gain adjustment is performed in order to match the levels of the TE signal and the FE signal because the levels of the TE signal and the FE signal are different depending on the reflectance of the optical disc 11 and the like. Then, the spindle servo is changed to a CD_CLV (Constant Linear Velocity) mode (step S110). Here, the CLV mode refers to setting the setting mode of the spindle motor 12 to a constant linear velocity.

  When the PP value of the amplitude of the TE signal measured in step S105 is a certain value or more (step S105; NO), the optical disc 11 is a CD whose distance from the surface of the optical disc 11 to the signal recording layer is 1.2 mm. Determined. If it is determined that the distance from the surface of the optical disc 11 to the signal recording layer is a 1.2 mm CD, coarse adjustment of the focus balance is performed (step S111). Here, the coarse adjustment of the focus balance means adjusting the focus balance value so that the focus signal (FS signal) becomes the largest. Here, the FS signal is a signal obtained by full addition (A + B + C + D) of signals received in the areas A, B, C, and D shown in FIG.

  After execution of step S111, the spindle servo is set to the rough sub mode (step S112). Then, the tracking servo is turned on (step S113).

  After execution of step S113, fine adjustment of the focus balance is performed (step S114). Here, the fine adjustment of the focus balance refers to adjusting the focus balance so that the jitter characteristic of the RF signal becomes the best. Then, gain adjustment of the focus servo and tracking servo is performed (step S115).

After execution of step S115, the spindle servo is changed to the CD_CLV mode (step S116). Then, fine adjustment of the focus balance is performed (step S117). The fine adjustment of the focus balance performed in step S117 is performed in order to improve playability.
After execution of steps S110 and S117, the CD media determination process ends.

Next, the focus balance control process executed in step S106 of the CD media determination process will be described with reference to FIG.
First, the loop processing counter is initialized (step S201). Here, initialization of the loop processing counter means setting the loop processing counter to an initial value “0”. Then, it is determined whether or not the focus servo has been removed (step S202). Here, the focus servo being out means that the focus servo cannot be turned on. When the focus servo is out (step S202; NO), a focus drop error occurs (step S209). In this case, the reproducing operation of the optical disc 11 cannot be performed.

  If the focus servo is not out in step S202 (step S202; YES), the PP value of the amplitude of the TE signal is measured (step S203). Then, it is determined whether or not the PP value of the amplitude of the TE signal is smaller than a certain value (step S204). Here, the constant value means a threshold value of the amplitude value of the TE signal at which the tracking servo can be turned on. . When the PP value of the amplitude of the TE signal is equal to or greater than a certain value (step S204; NO), the process is terminated normally (step S210). In this case, the tracking servo can be turned on and the optical disk 11 can be reproduced.

  If the PP value of the amplitude of the TE signal is smaller than a certain value in step S204 (step S204; YES), the focus balance setting value is changed (step S205). Here, changing the setting value of the focus balance means changing the offset value of the focus balance. The change of the offset value means, for example, that the (A + C) signal in FIG. 2 is offset by “+5”. In this case, since a difference of “5” occurs between (A + C) and (B + D) which are the focus balance, the focus balance is lost. For example, by changing the setting value of the focus balance, the state shown in FIG. That is, the pit ends where signals are read are applied to the areas E and F.

  After execution of step S205, it is determined whether or not the loop processing counter is 5 (step S206). Here, the threshold value of the loop processing counter is an arbitrary value. That is, the threshold value of the loop processing counter is “N” (N is an integer of 2 or more), and is not limited to “5”. In this embodiment, the threshold value of the loop processing counter is set to “5”.

In step S206, when the number of loop processing counters is 5 or more (step S206; NO), it is determined that the loop processing counter exceeds the upper limit (step S207). In this case, the optical disk 11 cannot be reproduced.

In step S206, if the loop processing counter is smaller than 5 (step S206; YES), the number of loop processing counters is incremented by 1 (step S208). After execution of step S208, the process proceeds to step S202, and the subsequent processing is repeated a predetermined number of times. At this time, every time the number of loop counters increases by “1”, the offset value of the focus balance is changed. For example, when the loop counter is “1”, the offset value of the (A + C) signal is changed by “+5”. When the loop processing counter is “2”, the offset value of the (B + D) signal is changed by “−5”. When the loop processing counter is “3”, the offset value of the (A + C) signal is changed by “+10”. When the loop processing counter is “4”, the offset value of the (B + D) signal is changed by “−10”. Similarly, every time the number of loop processing counters increases by “1”, the offset values of the (A + C) signal and the (B + D) signal are alternately changed.
After execution of steps S207, S209, and S210, the focus balance control process ends, and the process proceeds to step S107 in FIG.

  As described above, according to the present embodiment, the TE signal is detected from the surface of the optical disc 11 to the optical disc 11 (Dual disc) having a signal recording layer of 0.9 mm by changing the focus balance setting value. be able to. As a result, the tracking servo can be turned on without changing the hardware configuration such as the lens NA and the position of the light receiving element of the pickup. In this case, the playability is sacrificed, but the optical disk 11 can be reproduced.

  For example, when the present invention is used for an optical disk reproducing apparatus in which a dual disk is not applied (tracking servo cannot be turned on), service support can be performed by changing software.

  The description in the above embodiment is an example of the optical disc playback apparatus, the optical disc playback method, and the optical disc playback program according to the present invention, and is not limited thereto.

  For example, in the above-described embodiment, the configuration is such that the TE signal is detected by the three-beam method for the CD, but the TE signal may be generated by the three-beam method for an MD (Mini Disc) or the like.

  In addition, the detailed configuration and detailed operation of the optical disc playback apparatus 1 in the above embodiment can be changed as appropriate without departing from the spirit of the present invention.

1 is a schematic cross-sectional configuration diagram of an optical disc playback apparatus 1 according to the present invention. TE signal generation image when the focus is normally turned on to the 1.2 mm thickness layer, TE signal generation image when the focus is normally turned on to the 0.9 mm thickness layer, and the luminous flux is focused on the 0.9 mm thickness layer It is the figure which showed the production | generation image of TE signal when a focus is turned on in the state which shifted. It is a flowchart which shows the flow of CD media determination processing. It is a flowchart which shows the flow of a focus balance control process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk reproducing | regenerating apparatus 11 Optical disk 12 Spindle motor 13 Spindle driver 14 Optical pick-up 15 Objective lens 16 Photodetector 16A Photodetection circuit 16X, 16Y, 16Z Light-receiving surface 17 Light source 18 Feed motor 19 Tracking driver 20 RF amplifier 21 Focus driver 22 Actuator 23 Digital signal processing circuit 26 Control unit 27 Operation unit 28 Display unit 29 Timekeeping unit 30 Storage unit 31 Disk transport unit

Claims (5)

A light source, an objective lens for condensing the light beam emitted from the light source on the recording surface of the optical disc, and a photodetector for receiving the light beam reflected from the recording surface of the optical disc and outputting a detection signal corresponding to the received light amount With an optical pickup,
First driving means for moving the optical pickup in a radial direction of the optical disc;
A second driving means for moving the objective lens in a radial direction of the optical disc and moving the objective lens in a direction substantially perpendicular to a recording surface of the optical disc;
Generating means for generating a focus error signal and a tracking error signal based on a detection signal detected by the photodetector;
First measuring means for measuring the amplitude of the tracking error signal generated by the generating means;
First discriminating means for discriminating whether or not the optical disc is capable of turning on tracking servo based on the amplitude of the tracking error signal measured by the first measuring unit;
A control means for driving the second drive means to change the focus balance offset value and to turn on the focus servo and the tracking servo when the first determination means determines that the optical disk cannot be turned on by the tracking servo. ,
An optical disc reproducing apparatus comprising: The control means includes
A second measuring means for further measuring the amplitude of the tracking error signal when the offset value of the focus balance is changed;
A second discriminating unit that discriminates whether or not the amplitude of the tracking error signal measured by the second measuring unit is a detection level at which the tracking servo can be turned on;
When it is determined by the second determination means that the amplitude of the tracking error signal is smaller than a detection level at which the tracking servo can be turned on, the offset value of the focus balance is further changed and the second servo is turned on. And the second discriminating unit again discriminates the amplitude of the tracking error signal generated by the generating unit, while the second discriminating unit determines the amplitude of the tracking error signal by the tracking servo. 2. The optical disk reproducing apparatus according to claim 1, wherein when it is determined that the detection level is greater than a detection level that can be turned on, the second drive unit is driven to turn on a focus servo and a tracking servo. The control means includes
A third determining means for determining the number of changes in the offset value of the focus balance;
3. The optical disc reproducing apparatus according to claim 2, wherein when the number of changes of the offset value of the focus balance exceeds a predetermined number by the third discriminating unit, it is judged that the optical disc cannot be reproduced. . A light source, an objective lens for condensing the light beam emitted from the light source on the recording surface of the optical disc, and a photodetector for receiving the light beam reflected from the recording surface of the optical disc and outputting a detection signal corresponding to the received light amount An optical pickup; first driving means for moving the optical pickup in a radial direction of the optical disc; and moving the objective lens in a radial direction of the optical disc, and moving the objective lens substantially perpendicular to a recording surface of the optical disc. In an optical disc reproducing method of an optical disc reproducing apparatus, comprising: a second driving unit that moves in a direction; and a generating unit that generates a focus error signal and a tracking error signal based on a detection signal detected by the photodetector.
A measuring step of measuring the amplitude of the tracking error signal generated by the generating means by a measuring means;
A determination step of determining by a determination means whether or not the optical disk is capable of turning on tracking servo based on the amplitude of the tracking error signal measured in the first measurement step;
A control step of driving the second drive means by the control means so as to change the focus balance offset value and turn on the focus servo and tracking servo when the discriminating process determines that the optical disk cannot be turned on by the tracking servo. ,
An optical disc reproducing method comprising: Computer
Measuring means for measuring the amplitude of the tracking error signal;
Discriminating means for discriminating whether or not the optical disk can be turned on by tracking servo based on the amplitude of the tracking error signal measured by the measuring means;
When the discriminating unit discriminates that the optical disc cannot be turned on, the objective lens is moved in the radial direction of the optical disc so as to change the focus balance offset value and turn on the focus servo and the tracking servo. Control means for driving a drive means for moving the objective lens in a direction substantially perpendicular to the recording surface of the optical disc;
Optical disc playback program to function as

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