JP2004103190A - Method for discriminating kind of disk and disk device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for discriminating the kind of a disk, for discriminating the kind of the disk simply and to provide a disk device. <P>SOLUTION: The disk device 10 includes the disk 22, and a DVD-RW or a DVD+RW can be mounted as this disk 22. For example, a wobble signal is detected, based on laser beams reflected from the recording surface of the disk 22 to decide the presence/absence of a prepit signal from the wobble signal. When there is the prepit signal, the disk 22 is discriminated as being a DVD-RW. When there is not the prepit signal, the disk 22 is discriminated as being a DVD+RW. Since the kind of the disk can be discriminated only by the presence/absence of the prepit signal, the kind of the disk can easily be discriminated. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
[Industrial applications]
The present invention relates to a disc type discriminating method and a disc device, and more particularly to, for example, a disc type discriminating method and disc device that discriminates between DVD-RW and DVD + RW and executes recording and reproduction according to the disc type discriminated. About.
[0002]
[Prior art]
An example of a conventional disk device of this type is disclosed in Japanese Patent Application Laid-Open No. H11-163,837. In this conventional disk device, it is determined whether or not there is a wobble on the recording surface of the disk, and control data recorded at a predetermined address (address 2F200 or 2E400) on the recording surface of the disk is read to determine the type of the disk. Was determined.
[0003]
Another example of this type of disk device is disclosed in Patent Document 2. Another conventional disc discriminating apparatus discriminates a disc based on a frequency of a reproduction signal detected when the disc is rotated at a predetermined rotation speed.
[0004]
[Patent Document 1]
JP-A-2002-74658 (pages 5, 6 and FIG. 5)
[Patent Document 2]
JP-A-9-198779 (pages 4, 5 and FIG. 4)
[0005]
[Problems to be solved by the invention]
However, in the former case, it takes a long time to discriminate the disc because the control data is read as well as the presence or absence of the wobble.
[0006]
In the latter case, since the frequency of the reproduced signal is detected, a large-scale digital circuit for measuring the frequency is required.
[0007]
Therefore, a main object of the present invention is to provide a disc type discriminating method and disc device which can easily discriminate the disc type.
[0008]
[Means for Solving the Problems]
The first invention is a disc type discriminating method for discriminating between DVD-RW and DVD + RW, wherein (a) a wobble signal recorded on a recording surface of the disc is detected, and (b) a detected wobble signal is detected. (C) discriminating whether the disc type is DVD-RW or DVD + RW according to the presence or absence of the prepit signal.
[0009]
A second invention is a disc device that discriminates between DVD-RW and DVD + RW and executes recording and reproduction according to the disc type discriminated, and detects a wobble signal recorded on a recording surface of the disc. Detecting means, determining means for determining whether a pre-pit signal is included in the wobble signal detected by the detecting means, and determining whether the disc type is DVD-RW or DVD + RW according to the determination result of the determining means A disc device provided with a discriminating means for performing discrimination.
[0010]
[Action]
A DVD-RW or DVD + RW disk can be mounted on the disk device. For example, a wobble signal is detected based on a laser beam reflected from a recording surface of a disk, and the presence or absence of a pre-pit signal is determined from the wobble signal. Then, it is determined whether the disc type is DVD-RW or DVD + RW according to the presence or absence of the pre-pit signal.
[0011]
For example, it is determined whether the level of the wobble signal is higher than a predetermined threshold. If the result of the comparison indicates that the level of the wobble signal is higher than the predetermined threshold, it is determined that there is a pre-pit signal. If the signal level is smaller than a predetermined threshold, it is determined that there is no pre-pit signal. If there is a pre-pit signal, it is determined that the disc is a DVD-RW, and if there is no pre-pit signal, it is determined that the disc is a DVD + RW.
[0012]
【The invention's effect】
According to the present invention, since the type of the disc is determined based on the presence or absence of the pre-pit signal, the type of the disc can be easily determined.
[0013]
The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.
[0014]
【Example】
Referring to FIG. 1, a disk device 10 of this embodiment includes an optical pickup 12, and the optical pickup 12 is provided with an objective lens. This objective lens 14 is supported by a tracking actuator 16 and a focus actuator 18. The laser light emitted from the laser diode 20 is applied to a recording surface of a disk 22 such as a DVD-RW or a DVD + RW via an optical system (not shown) and the objective lens 14.
[0015]
The disk 22 is mounted (chucking) on a turntable 24 and rotated by a spindle motor 26. For example, the disk 22 can rotate in a CLV (Constant Linear Velocity) system, and the number of rotations decreases as the optical pickup 12 moves from the inner circumference to the outer circumference.
[0016]
On the recording surface of the disk 22, convex land tracks and concave groove tracks are alternately formed for each track.
[0017]
With reference to FIGS. 2A and 2B, the laser beam irradiated on the recording surface is specifically composed of one main beam M and two sub beams S1 and S2. Of these, the main beam M is applied to a desired track (groove track), and the sub-beams S1 and S2 are applied to tracks adjacent to both sides of the desired track (land track).
[0018]
For the sake of simplicity, FIG. 2A shows only a DVD + RW disc 22, but in the case of a DVD-RW disc 22, land prepits (LPPs) are formed at predetermined intervals (positions). Is done.
[0019]
The laser light reflected on the recording surface is irradiated on the photodetector 28 via the objective lens 14 and the optical system. The main beam M is detected by the light detecting elements 28a to 28d, the sub beam S1 is detected by the light detecting elements 28e and 28f, and the sub beam S2 is detected by the light detecting elements 28g and 28h.
[0020]
The main beam M, the sub beam S1, and the sub beam S2 detected by the photodetectors 28a to 28h are respectively converted into currents and output to the matrix amplifier 30. The matrix amplifier 30 subjects the outputs of the photodetectors 28 (the photodetectors 28a to 28h) to well-known arithmetic processing as shown in Expressions 1 to 4, and performs a tracking error (TE) signal and a focus error (FE). A signal, a wobble signal, and an RF signal are detected, respectively. However, the TE signal is detected by a differential push-pull (DPP) method, and the wobble signal is detected by a push-pull (PP) method.
[0021]
(Equation 1)
TE = {(A + B) − (C + D)} − α {(E + H) − (F + G)}
[0022]
(Equation 2)
FE = (A + C)-(B + D)
[0023]
[Equation 3]
Wobble = (A + B)-(C + D)
[0024]
(Equation 4)
RF = A + B + C + D
Note that “A” to “H” in Equations 1 to 4 correspond to the outputs of the photodetectors 22a to 22h, respectively.
[0025]
Returning to FIG. 1, the TE signal, the FE signal, and the wobble signal detected by the matrix amplifier 30 are respectively supplied to the DSP 32 via an A / D converter (not shown). The DSP 32 executes tracking servo and sled servo based on the digitally converted TE signal, and generates a tracking actuator control signal and a sled motor control signal. The generated tracking actuator control signal and sled motor control signal are converted into a tracking actuator control voltage and a sled control voltage by the driver 34b and the driver 34c, respectively, and supplied to the tracking actuator 16 and the sled motor 36, respectively. Thus, the position of the optical lens 14 in the radial direction (sled direction), the rotational speed and the rotational direction of the sled motor 36 are controlled. However, since the thread motor 36 is connected to the optical pickup 12 by a rack and pinion method or the like, as is well known, the moving direction (moving speed) and position (displacement) of the optical pickup 12 are controlled by the thread servo.
[0026]
The DSP 32 executes focus servo based on the digitally converted FE signal, and generates a focus control signal. The generated focus control signal is converted into a focus control voltage by the driver 34 a and provided to the focus actuator 18. Thereby, the focus, that is, the position (lens position) on the optical axis of the objective lens 14 is adjusted. That is, the position in the focus direction is adjusted.
[0027]
Further, the DSP 32 executes a spindle servo (hereinafter, referred to as “CLV servo”) based on the digitally converted wobble signal, and generates a spindle control signal. The generated spindle control signal is converted into a spindle motor control voltage by the driver 34 d and supplied to the spindle motor 26. Thus, the rotation speed and the rotation direction of the spindle motor 26 (turntable 24), that is, the disk 22, are adjusted.
[0028]
However, at the beginning when the disk 22 is mounted on the disk device 10, the signal of the disk 22, that is, the wobble signal cannot be read accurately, so that the spindle servo by the FG pulse is executed. That is, the rotation speed of the spindle motor 26 is pulse-converted by an encoder (not shown), and the FG pulse generated thereby is given to the DSP 32. The DSP 32 detects the number of rotations of the spindle motor 26 based on the given FG pulse, and generates a spindle control signal so that the number of rotations reaches a desired value. The generated spindle control signal is converted into a spindle motor control voltage by the driver 34 d and supplied to the spindle motor 26.
[0029]
As described above, the spindle servo (FG servo) can be executed based on the FG pulse, but the rotation control is coarser than that of the CLV servo.
[0030]
The RF signal (reproduced signal) detected by the matrix amplifier 30 is provided to the encoder / decoder 38. The encoder / decoder 38 is an IC or the like in which an encode and a decoder are integrally formed. The encoder / decoder 38 decodes an RF signal according to address information given from a DVD + RW address detection circuit (decoder) 42 or a DVD-RW address detection circuit (decoder) 44 under the instruction of the CPU 40, and provides an interface (I / F). To a host computer such as a PC (not shown).
[0031]
The decoder 42 detects a position (reversal position) at which the phase of the wobble signal obtained when the DVD + RW disc 22 is reproduced (reversal position), and based on the reversal position, the detected address information and recording timing information are encoded / encoded. It is provided to the decoder 38.
[0032]
The decoder 44 detects a pre-pit signal included in a wobble signal obtained when the DVD-RW disc 22 is reproduced, and converts the address information detected based on the pre-pit signal and the timing information at the time of recording into an encoder / decoder. Give to 38.
[0033]
The decoder 42 and the decoder 44 are switched by a switch SW. The switch SW is switched by the CPU 40 according to the type of the disk 22 mounted on the disk device 10.
[0034]
The encoder / decoder 38 encodes a signal (recording signal) input from the host computer to generate a pit signal, and converts the pit signal into a laser driving circuit 46 according to address information and timing information from the decoder 42 or the decoder 44. Give to. The laser drive circuit 46 drives the laser diode 20 according to a pit signal provided from the encoder / decoder 38 under the instruction of the CPU 40. Therefore, a recording signal given from the host computer is recorded at a desired position (address) on the recording surface of the disk 22.
[0035]
As described above, a signal can be reproduced from the disk 22 or a signal can be recorded on the disk. However, since the disk 22 mounted on the disk device 10 is a DVD-RW or a DVD + RW, no care is taken. In such a case, signal recording and reproduction cannot be properly performed. In other words, the wobble cycle of the DVD-RW is 186T (T is the data cycle), whereas the wobble cycle of the DVD + RW is 32T. If it is determined that the DVD + RW disc 22 is loaded in spite of the loading, the CLV servo cannot be executed accurately, and the spindle motor 26 may run away. Because there is.
[0036]
Therefore, in this embodiment, when the main power supply of the disk device 10 is turned on or the disk 22 is replaced (mounted), it is determined whether the disk 22 is a DVD-RW or a DVD + RW. is there. For example, the type of the disk 22 is determined according to the presence or absence of an LPP (pre-pit signal). That is, as shown in FIGS. 3A and 3B, only the wobble signal is detected on the DVD + RW disc 22, whereas the wobble signal is pre-pitched at a predetermined cycle on the DVD-RW disc 22. Signal is included (superimposed).
[0037]
As shown in FIG. 3A, in the DVD + RW disc 22, the phase of the wobble signal is inverted at a predetermined cycle.
[0038]
This can be seen from FIG. 4 (A) and FIG. 4 (B), which show a part of the structure of the disc 22, in the DVD + RW disc 22, as shown in FIG. Tracks and land tracks) are formed only by wobbles, whereas in the DVD-RW disc 22, as shown in FIG. 4B, a predetermined period (predetermined interval) is provided between land tracks between adjacent groove tracks. This forms an LPP. Therefore, as described above, the presence or absence of the pre-pit signal is detected.
[0039]
Strictly speaking, the disk 22 is formed by laminating a PC substrate, a reflective layer, a protective layer, and a recording layer, but is omitted in FIG. 4 for simplicity.
[0040]
That is, as shown in FIG. 1, the wobble signal output from the matrix amplifier 30 is input to the comparator 48, and the level of the wobble signal is higher than a predetermined threshold (see FIGS. 3A and 3B). Whether or not there is a pre-pit signal is determined based on whether or not there is a pre-pit signal. Specifically, when the level of the wobble signal is higher than a predetermined threshold, a high-level signal is input from the comparator 48 to the CPU 40, whereby the CPU 40 determines that the disk 22 is a DVD-RW. On the other hand, when the level of the wobble signal is smaller than the predetermined threshold value, a low-level signal is input from the comparator 48 to the CPU 40, whereby the CPU 40 determines that the disk 22 is DVD + RW.
[0041]
The predetermined threshold value is a value obtained in advance by an experiment or the like. As will be described later, when discriminating the type of the disk 22, the spindle motor 26 is driven to rotate by the FG servo, so that the predetermined threshold value is not affected by noise even in rough rotation control like the FG servo. Determined by the value. Further, since the pre-pit signal is also detected on the positive side (upper side in the drawing), in FIGS. 3A and 3B, it is shown that thresholds are provided on both the positive side and the negative side. However, in practice, the absolute value of the wobble signal is input to the comparator 48 and compared with one (positive side) threshold value.
[0042]
Specifically, the CPU 40 executes the disc type determination processing according to the flowchart shown in FIG. For example, when the main power supply of the disk device 10 is turned on or the disk 22 is exchanged (mounted), the CPU 40 starts processing, turns on the spindle in step S1, and executes the FG servo. That is, the CPU 32 instructs the DSP 32 to drive the spindle motor 26 and execute the FG servo, and in response, the DSP 32 drives the driver 34d based on the FG pulse. That is, the spindle motor 26 (disk 22) is controlled to rotate in a desired rotation direction and a desired rotation speed.
[0043]
Next, in step S3, the laser is turned on, in step S5, the focus is turned on, in step S7, the tracking is turned on, and in step S9, the thread is turned on. That is, the CPU 40 instructs the laser drive circuit 46 to turn on the laser diode 20, and then instructs the DSP 32 to execute focus servo, tracking servo, and thread servo.
[0044]
Subsequently, in step S11, it is determined whether or not the level of the wobble signal is higher than a predetermined threshold. That is, it is determined whether the signal input from the comparator 48 is at a high level or a low level. If “YES” in the step S11, that is, if the signal input from the comparator 48 is at a high level, it is determined that the level of the wobble signal is larger than a predetermined threshold, and the decoder 42 is selected in a step S13. That is, the type of the disc 22 is determined to be DVD-RW, and the switch SW is switched to the decoder 42 side. Then, in step S15, the CLV servo parameters (CLV parameters) for the DVD-RW are set in the DSP 32, and the process ends.
[0045]
On the other hand, if “NO” in the step S11, that is, if the signal input from the comparator 48 is a low level, it is determined that the level of the wobble signal is smaller than a predetermined threshold, and the decoder 44 is selected in a step S17. . That is, the type of the disk 22 is determined to be DVD + RW, and the switch SW is switched to the decoder 44 side. Then, in step S19, the CLV parameter for the DVD + RW is set in the DSP 32, and the process ends.
[0046]
As described above, the type of the disk 22 is determined, and the decoder 42 or the decoder 44 is selected according to the determination result, and the CLV parameter corresponding to the type of the disk 22 is set in the DSP 32. Regeneration is performed properly.
[0047]
Although omitted in the flowchart, as described above, since the LPP is formed in the wobble at predetermined intervals, a wobble signal is detected for a time longer than this predetermined period, and the determination processing in step S11 is performed. Is executed.
[0048]
According to this embodiment, since the type of the disc is determined according to the presence or absence of the pre-pits, the disc type can be easily determined. Therefore, recording and reproduction of the disc can be started in a short time.
[Brief description of the drawings]
FIG. 1 is a block diagram showing one embodiment of the present invention.
FIG. 2A is an illustrative view showing a state in which a main beam and a sub-beam are irradiated on a recording surface of a disk, and FIG. 2B is an illustrative view showing a configuration of a light detection unit.
FIG. 3A is an illustrative view showing a wobble signal read from a DVD + RW, and FIG. 3B is an illustrative view showing a wobble signal read from a DVD-RW;
FIG. 4A is an illustrative view showing a part of a DVD + RW disc structure, and FIG. 4B is an illustrative view showing a part of a DVD-RW disc structure;
FIG. 5 is a flowchart showing a disc discrimination process of a CPU shown in the embodiment of FIG. 1;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Disk apparatus 12 ... Optical pick-up 30 ... Matrix amplifier 32 ... DSP
40 ... CPU
42 DVD + RW address detection circuit (decoder)
44… DVD-RW address detection circuit (decoder)
48… Comparator

Claims (4)

A disc type discriminating method for discriminating between DVD-RW and DVD + RW,
(A) detecting a wobble signal recorded on the recording surface of the disc,
(B) discriminating the presence or absence of a pre-pit signal from the detected wobble signal; and (c) discriminating whether the disc type is DVD-RW or DVD + RW according to the presence or absence of the pre-pit signal. Method. The step (b) comprises: (b-1) comparing the level of the detected wobble signal with a predetermined threshold; (b-2) the pre-pit signal when the level of the wobble signal is higher than the predetermined threshold. (B-3) determining that the pre-pit signal is not present when the level of the wobble is smaller than the predetermined threshold value;
The step (c) comprises: (c-1) determining the type of the desk as DVD-RW when the pre-pit signal exists; and (c-2) changing the type of the disk to DVD + RW when the pre-pit signal does not exist. 2. The disc type discriminating method according to claim 1, further comprising a discriminating step. A disc device that discriminates between DVD-RW and DVD + RW, and performs recording and reproduction according to the disc type discriminated,
Detecting means for detecting a wobble signal recorded on the recording surface of the disk,
Judging means for judging whether or not the wobble signal detected by the detecting means contains a pre-pit signal, and judging whether the type of the disc is DVD-RW or DVD + RW according to the judgment result of the judging means. A disk device comprising a determination unit for performing the determination. Comparing means for comparing the level of the wobble signal detected by the detecting means with a predetermined threshold value,
The determining means determines that the pre-pit signal is present when the level of the wobble signal is higher than the predetermined threshold, and determines that the pre-pit signal is not present when the level of the wobble signal is lower than the predetermined threshold,
4. The disc device according to claim 3, wherein the discriminating means discriminates the disc type as DVD-RW when the prepit signal is included, and discriminates the disc type as DVD + RW when the prepit signal is not included.

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