JP2006228267A - Optical disk device and unrecorded part discrimination method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a servo from being out of control by detecting, as early as possible, that a position irradiated with a laser beam is an unrecorded part of a disk, since spindle servo controlling a rotational number and tracking servo using a tracking error signal cannot be carried out to an unrecorded part of a disk and the servo can be out of control in an optical disk device. <P>SOLUTION: An unrecorded part of a disk is determined with high precision, based on whether a phase difference TE signal normalized with an AS signal reaches a prescribed reference value, to prevent a servo from being out of control at the unrecorded part, by using the AS signal which is the light quantity sum signal of the reflected light from the disk and the TE signal generated by a phase difference generated in accordance with the deviation quantity of tracking, and utilizing the characteristic of the AS signal that its amplitude is larger in a recording part than in an unrecorded part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an information recording medium, an information recording / reproducing apparatus, and a method, and particularly relates to a reproducible reproducing DVD player, a recording / reproducing DVD player, and a technology applicable to these DVD players.

  As shown in FIG. 3, the conventional optical disk apparatus stores pit information written on an optical disk 1 on which video and audio such as a DVD (digital versatile disk) and a CD (compact disk) are recorded in an optical pickup 2. Reading is performed by controlling the focus, tracking actuator, and various motors provided, preprocessing such as AGC processing and waveform equalization processing is performed in the reproduction signal processing circuit 4, and then converted into a digital signal by the A / D conversion circuit 5.

  The DSP 6 determines a slice level at the time of A / D conversion for the input reproduction signal, a Sync detection process for detecting a synchronization pattern in the binarized reproduction signal, and the binarized reproduction signal Digital signal processing such as generation of a clock synchronization signal using a self-clock component, Viterbi correction for a reproduction signal, and generation of various control signals are performed. The digitally processed signal is demodulated by the demodulation circuit 12, and an image or Output as audio.

In these processes, it is the role of the microcomputer 11 to control the DSP 6 and the demodulation circuit 12. Conventionally, a mechanism for determining whether a set disc is a recorded disc or an unrecorded disc has been implemented in an optical disc apparatus. One of them is a tracking error signal by a phase difference method. (Hereinafter referred to as a phase difference TE signal). The phase difference TE signal is detected using a temporal change of reflected light obtained when a beam spot on the disk crosses each pit, and is zero in an unrecorded portion where no pit is formed. . This feature is used for unrecorded discrimination using the phase difference TE signal. The phase difference method used here detects the TE signal from individual pits crossed by the beam spot, so Another characteristic is that it is easily affected by depth.
Japanese Patent Laid-Open No. 2002-50054

  When an unrecorded optical disk or a disk with a narrow recording part (mostly unrecorded part) is set in the optical disk apparatus, the unrecorded part of the disk uses a spindle servo or TE signal for controlling the rotation speed. There is a possibility that the tracking servo may not be performed and the servo may run away. Therefore, it is necessary to detect as soon as possible that the position where the laser is irradiated is an unrecorded portion of the disk, and to prevent servo runaway.

  As a method for detecting an unrecorded portion of a disc, there is a method using a TE signal by a phase difference method generated by a tracking deviation amount. Even if this method is used, the TE amplitude due to the influence of the reflectivity of the disc is used. There is a possibility that unrecorded detection may be mistaken due to the influence of change or noise. Therefore, an object of the present invention is to prevent uncontrollable servo runaway in a non-recorded portion of a disk by devising undetected recording with higher accuracy.

  In the optical disk apparatus of the present invention, when an unrecorded disk or a disk with a narrow recording section is set, a recording section is obtained using the phase difference TE signal and a light amount sum signal (hereinafter referred to as an AS signal) of the reflected light of the disk. Taking advantage of the characteristic of the AS signal in which the signal amplitude of the unrecorded part becomes larger than that, the unrecorded part of the disc is determined with high accuracy by whether or not the phase difference TE signal normalized by the AS signal reaches a predetermined reference value.

  In the optical disc apparatus according to the present invention, when an unrecorded disc or a disc having a narrow recording portion is set, the unrecorded portion of the set disc can be determined with high accuracy. It is possible to prevent it.

  According to the first to fourth aspects of the present invention, there is provided an optical pickup for reading recorded information from an optical disc, and a temporal change in reflected light obtained when the optical pickup is shifted in the radial direction of a track and crosses a pit. A phase difference TE signal generated by the TE generation means, comprising: a TE generation means for generating a tracking error signal by a phase difference method utilizing a phase difference method; and an AS generation means for generating a light amount sum signal of the reflected light from the optical disc; Position detection means for detecting a position where the optical pickup is irradiating the optical disk with respect to the optical disk using both AS signals generated by the AS generation means, and a position where the optical pickup is irradiating the laser The recording unit changes the position of the optical pickup by the non-recording judging means for judging whether the recording part is a recording part or an unrecorded part. Execution of the regeneration operation, the unrecorded portion is performed to stop the playback operation.

  As a result, when an unrecorded disk or a disk with a narrow recording section is set, an unrecorded area is recorded by using the phase difference TE signal and a light sum signal of reflected light from the disk (hereinafter referred to as an AS signal). Taking advantage of the characteristic of the AS signal in which the signal amplitude of the part increases, the unrecorded part of the disc is determined with high accuracy by whether or not the phase difference TE signal normalized by the AS signal reaches a predetermined reference value.

(Embodiment 1)
FIG. 1 shows a block diagram of Embodiment 1 of the present invention.

  In the figure, reference numeral 1 denotes an optical disc that is a recording medium on which video signals, audio signals, various information signals, and the like are recorded. In this embodiment, a DVD (digital versatile disc) or a CD (compact disc) is used. However, the present invention is not limited to these, and any optical recording medium may be used.

  An optical pickup 2 is a reading means for reading out pit information recorded on the optical disc 1, and is a laser diode that irradiates an optical signal, a beam splitter that splits an optical signal reflected from the recording surface of the optical disc 1, an actuator, and an optical signal. It comprises a light receiving element (photo detector) for receiving the light.

  Reference numeral 3 denotes various motors which are driving means provided for focusing, tracking actuator and disk rotation, and movement of the optical pickup provided in the optical pickup 2, and their operations are controlled by the microcomputer 11.

  Reference numeral 4 denotes a reproduction signal processing circuit which is reproduction signal processing means for inputting pit information output from the optical pickup 2 and performing preprocessing such as AGC (automatic gain control) processing and waveform equalization processing.

  Reference numeral 5 denotes an analog / digital conversion circuit (hereinafter referred to as an A / D conversion circuit) which is an A / D conversion means for converting the pit information of the analog signal preprocessed by the reproduction signal processing circuit 4 into a digital signal.

  Reference numeral 6 denotes a slice level determination at the time of A / D conversion with respect to the input reproduction signal, a Sync detection process for detecting a synchronization pattern in the binarized reproduction signal, and the binarized reproduction signal self. AS generation by a digital signal processor (hereinafter referred to as DSP) which is a signal processing means for generating a clock synchronization signal using a clock component, digital signal processing such as Viterbi correction for a reproduction signal, and generation of various control signals. The circuit 7 is composed of a TE generation circuit 8 and an unrecorded determination means 9.

  Reference numeral 7 denotes an AS generation circuit which is an AS generation means for generating a light quantity sum signal (AS signal) based on input pit information. The AS signal has a signal level in a recording portion of a recording track of the optical disc 1 and an unrecorded portion. Becomes lower than the signal level at.

  A TE generation circuit 8 is a TE generation unit that generates a phase difference tracking error signal based on input pit information.

  Reference numeral 9 denotes a position detection means 10 that uses both the AS signal generated by the AS generation circuit 7 and the phase difference TE signal generated by the TE generation circuit 8 to determine the position where the optical pickup 2 is irradiating the laser. It is an unrecorded determination means for determining whether or not the position irradiated with the laser is an unrecorded portion while detecting.

  Reference numeral 10 denotes position detection means for detecting the position where the optical pickup 2 is irradiating the laser.

  Reference numeral 11 denotes a microcomputer (hereinafter referred to as a microcomputer) which is a control means for controlling each circuit / means.

  Reference numeral 12 denotes a demodulation circuit which is demodulation means for demodulating a signal output from the DSP 6 into a video / audio signal.

  13 is an output terminal for outputting the video / audio signal demodulated by the demodulation circuit 12 to the outside.

  The operation of the embodiment configured as described above will be described below.

  When the optical disc 1 on which video or music such as a DVD or CD is set in the optical disc apparatus according to the present invention, the pit information written on the optical disc 1 is used for focusing and tracking provided in the optical pickup 2. Reading is performed by controlling various motors 3 provided for the rotation of the actuator and the disk and the movement of the optical pickup. The read pit information is input to the reproduction signal processing circuit 4, and after preprocessing such as AGC processing and waveform equalization processing is performed by the reproduction signal processing circuit 4, the A / D conversion circuit 5 converts it into a digital signal.

  The digital signal from the A / D conversion circuit 5 is input to the DSP 6. The DSP 6 determines the slice level at the time of A / D conversion with respect to the input reproduction signal, and synchronizes the binarized reproduction signal. Sync signal detection processing for detecting a pattern, generation of a clock synchronization signal using a self-clock component of a binarized reproduction signal, and Viterbi correction for the reproduction signal, and generation of various control signals are performed. The signal digitally processed by the DSP 6 is demodulated by the demodulation circuit 12 and output from the output circuit 13 as video or audio.

  The DSP 6 includes an AS generation circuit 7 for generating an AS signal corresponding to the amount of reflected light from the disk and a TE generation circuit 8 for generating a TE signal by a phase difference method. These various control signals are processed by servo processing. Used when executing The unrecorded determination means 9 uses the AS signal generated by the AS generation circuit 7 and the phase difference TE signal generated by the TE generation circuit 8 to irradiate the optical pickup 2 with a laser. While detecting the position by the position detection means 10, it is determined whether or not the position where the laser is irradiated is an unrecorded portion.

  In the operation of such an optical disk apparatus, it is the role of the microcomputer 11 to control the DSP 6 and the demodulation circuit 12.

  The optical pickup 2 is provided with a photodetector as shown in FIG. In FIG. 2, an adder 21, an adder 22, and an adder 23 correspond to the AS generation circuit 7 in FIG. 1, and an adder 24, an adder 25, a phase comparator 26, and an LPF 27 are the TE generation circuit in FIG. Equivalent to 8. In FIG. 2, reference numerals 4 and 5 in FIG. 1 are omitted for the sake of explanation.

  In the optical disc apparatus according to the present invention, when the optical pickup 2 irradiates a pit on the optical disc 1 with a laser, the reflected light from the optical disc 1 is separated by a beam splitter, and a light spot is applied to the tracking detector and the focus detector. Form. Of the four light spots on the tracking photo detectors a, b, c, and d, two photo detectors a, c, b, and d arranged on a diagonal line are added by the adder 24 and the adder 25, respectively. The phase comparator 26 generates a signal based on the phase difference between the two signals. The generated signal passes through the LPF 27 and is generated as a TE signal by the phase difference method. Further, light spots formed on the respective dividing lines of the four focus photodetectors e, f, g, h by the light focused on the front side and the light focused on the rear side across the light receiving element surface, By adding all using the adder 21, the adder 22, and the adder 23, an AS signal is generated.

  In the description of the present invention, the light spot formed on the focus photodetector is added to obtain the AS signal. However, the light spot formed on the tracking photodetector can be added to obtain the AS signal. Needless to say, it is also possible to add all the light spots formed on the focus and tracking photodetectors to form an AS signal.

  An unrecorded portion detection method according to the present invention is shown in FIG. 1 to 3 and 7 to 11 shown in FIG. 4 have the same configurations as those in FIG. 1 to 4, 12, and 13 are naturally included in the configuration, but the explanation is omitted in FIG. 4 for convenience of explanation. In the optical disc apparatus according to the present invention, when the optical disc 1 set at the playback position is an unrecorded disc or a disc with a narrow recording section, the unrecorded optical disc 1 set at an early stage before the playback operation is performed. It is conceivable that the optical pickup 2 irradiates the part with a laser. In this case, since the rotation servo for controlling the rotation speed and the tracking servo using the TE signal cannot be performed in the unrecorded portion of the disk, the servo may run away.

Therefore, in the optical disc apparatus according to the present invention, the AS signal generated by the AS generation circuit 7 and the TE generation circuit 8 is utilized by utilizing the characteristic of the AS signal that the amplitude of the unrecorded portion is larger than the recorded portion of the disc. And the phase difference TE signal,
TEn = TE / AS
The recorded / unrecorded part of the disc is judged by the unrecorded judgment means 9 for judging whether the level of the phase difference TE signal TEn normalized based on the above formula exceeds a predetermined reference value. .

  By normalizing the phase difference TE signal with the AS signal, the influence of noise and disk reflectivity is reduced, and erroneous detection of an unrecorded portion can be prevented. Therefore, the optical pickup 2 emits a laser beam. It is possible to detect with high accuracy whether the current position is the recording portion or the unrecorded portion of the disk.

  Further, in the optical disc apparatus according to the present invention, the position of the optical pickup 2 is changed by the control of the motor 3 while the position of the optical pickup 2 is changed by the position detection means 10 for detecting the position where the optical pickup 2 irradiates the laser. When a disk with a narrow recording section is set, the optical pickup 2 is sent in the inner circumferential direction of the disk, and then the reproducing operation can be executed with the recording section detected using the unrecorded determination means 9 If an unrecorded disc is set, it is determined that the disc has not been recorded even after the optical pickup 2 is sent in the inner circumferential direction. Therefore, playback is performed before the servo process is executed. It is possible to stop the operation.

  Note that the unrecorded judging means 9 and the position detecting means 10 in FIG. 4 can also be realized by software on the microcomputer 11 as shown in the flowchart of FIG. After the optical disk 1 is set in the optical disk apparatus, a disk search is performed while controlling the focus actuator of the optical pickup 2 in step S1. After the disk search, in step S2, the AS signal and the phase difference TE signal at the position where the optical pickup 2 is irradiating the laser are generated while rotating the optical disk 1 at a predetermined rotational speed. Next, in step S3, the detected value of the phase difference TE signal is divided by the detected value of the AS signal, and in step S4, a comparison with a predetermined reference value is performed. When it is determined by comparison with the reference value that the result of dividing the phase difference TE signal by the AS signal is larger than the reference value, the position where the optical pickup 2 is irradiating the laser is the recording unit Therefore, servo processing is executed in step S5. Conversely, if it is determined that the value is smaller than the reference value, it is determined in step S6 whether or not the optical pickup 2 is at the innermost position of the optical disc 1. If the result of the determination is that the optical pickup 2 is at the innermost circumference, the set optical disc 1 is an unrecorded disc, and the reproduction operation is stopped in step S7. On the contrary, when the optical pickup is not located on the innermost circumference, the motor 3 is controlled to send the optical pickup 2 to the innermost circumference of the optical disc 1, and again the AS signal and the phase difference at the innermost circumference position. A TE signal is generated.

  With the above operation, in the optical disc apparatus according to the present invention, the unrecorded portion of the optical disc 1 set in the stage before executing the servo processing is determined with high accuracy, and the servo is prevented from running out of control in the unrecorded portion. Is possible.

  The optical disk apparatus according to the present invention can be used as an optical disk apparatus capable of detecting an unrecorded portion with high accuracy with little influence of reflectance and noise.

Block diagram of an optical disc apparatus according to the present invention Block diagram for optical pickup configuration and error signal generation Block diagram of a conventional optical disk device Block diagram of an unrecorded portion detection method in the present invention Flowchart of unrecorded portion detection method in the present invention

Explanation of symbols

1 optical disk 2 optical pickup 3 motor 4 reproduction signal processing circuit 5 A / D conversion circuit 6 DSP
7 AS generation circuit 8 TE generation circuit 9 Unrecorded determination means 10 Position detection means 11 Microcomputer 12 Demodulation circuit 13 Output circuit 21 Adder 22 Adder 23 Adder 24 Adder 25 Adder 26 Phase comparator 27 LPF

Claims (4)

An optical pickup that reads recorded information from an optical disk, and a TE generator that generates a tracking error signal by a phase difference method using a temporal change of reflected light obtained when the optical pickup crosses a pit by shifting in the radial direction of the track Means and AS generation means for generating a light amount sum signal of the reflected light from the optical disc,
Position detecting means for detecting a position where the optical pickup irradiates the optical disk with respect to the optical disk, using both the phase difference TE signal generated by the TE generating means and the AS signal generated by the AS generating means. And a non-recording judging means for judging whether the position where the optical pickup is irradiating the laser is a recording part or an unrecorded part, while the recording part performs a reproducing operation while changing the position of the optical pickup. An optical disc apparatus characterized in that a reproducing operation is stopped in a recording unit. A signal obtained by normalizing the phase difference TE signal generated by the TE generation circuit with the AS signal generated by the AS generation circuit is compared with a predetermined reference value to determine whether it is a recorded portion or an unrecorded portion. The optical disc apparatus according to claim 1. An optical pickup that reads recorded information from an optical disc, and a TE that generates a tracking error signal by a phase difference method using a temporal change of reflected light obtained when the optical pickup deviates in the radial direction of the track. A generation circuit and an AS generation circuit that generates an AS signal that is equal to or less than the light amount sum signal of the reflected light from the optical disc. Both the phase difference TE signal generated by the TE generation circuit and the AS signal generated by the AS generation circuit To determine whether the position where the optical pickup is irradiating the optical disk with respect to the optical disc is a recorded portion or an unrecorded portion. The phase difference TE signal generated by the TE generation circuit is normalized by the AS signal generated by the AS generation circuit and compared with a predetermined reference value to determine whether it is a recorded portion or an unrecorded portion. The method for discriminating an unrecorded part according to claim 3.

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