JP2010186523A - Optical disk device, and optical disk discrimination method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem of the conventional method for discriminating optical disks between a DVD-RAM and a DVD-RW in an optical disk device, to be the DVD-RAM when the reflective ratios of a laser light in a RAM area and a ROM area on the recording surface thereof are largely different, while to be the DVD-RW when the above difference is small, which produces a long setup time because an optical pickup is required to move back and forth between the RAM area and the ROM area. <P>SOLUTION: When the optical disk is mounted, focus servo control is performed, and thereafter, the optical pickup is made to transversely travel across a plurality of recording tracks, without the execution of tracking servo control. Then, a TE signal frequency and a wobble signal envelope frequency are measured and compared. The setup time is reduced by the decision of the DVD-RW if the both are equal, while the DVD-RAM if the both differ by twice or half. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an optical disc apparatus and an optical disc discriminating method of the optical disc device, and more particularly to an optical disc device that shortens the time required for discriminating the type of an optical disc mounted, and an optical disc discriminating method of the optical disc apparatus.

  In an optical disc apparatus using a DVD (Digital Versatile Disc) as a recording medium, rewritable RAM (Random Access Memory) type, RW (Rewritable) type, and R (Recordable) type that can be written only once are used. Those that can record information are widespread. In such a digital recording apparatus, recording and reproduction operation settings differ depending on the optical disk to be used. For this reason, it is necessary to determine the type of the optical disk in the setup state when the optical disk is loaded.

Since DVD-R has higher reflectivity of laser light than DVD-RAM and DVD-RW due to the nature of the material, it can be determined by detecting the intensity of the reflected light.
An example of the discrimination between DVD-RAM and DVD-RW is disclosed in Patent Document 1. In particular, as shown in Table 2 of Patent Document 1, a DVD-RAM is a ROM in which a tracking error signal (hereinafter referred to as a TE signal) in a RAM area in which data is recorded records the type of an optical disk in the inner periphery ( In many cases, the DVD-RW discriminates by making use of the fact that it is three times or more larger than the TE signal in the (Read Only Memory) area, for example, while DVD-RW is roughly equal. This is due to the difference in the structure of each optical disc.

JP 2001-184676 A

  When discriminating whether the optical disc is a DVD-RAM or a DVD-RW, the above-described method discriminates after the optical pickup moves between the inner peripheral ROM area and the outer RAM area by a method called seek. There is a need to. With this as one factor, at present, it takes a time on the order of seconds to discriminate an optical disc. It is necessary to shorten the rise time until the recording / reproducing can be actually performed after the optical disk is mounted in order to improve the user-friendliness. For this purpose, it is necessary to develop a technique for further reducing the time required for discriminating the type of optical disc.

  An object of the present invention is to solve this problem and to provide an optical disc apparatus and a method for discriminating an optical disc of the optical disc apparatus, in which the time required for discriminating the type of the mounted optical disc is shortened.

  In order to achieve the above object, the present invention provides an optical disc apparatus using as a recording medium at least two types of optical discs, a DVD-RAM and a DVD-RW, on which recording tracks having a shape having periodic fluctuations are formed in advance. A signal is recorded on the medium using a laser beam, and an optical pickup that reproduces the signal based on the reflected light of the laser beam from the recording medium, and the signal is processed and given to the optical pickup during the recording, A signal processing circuit for processing the signal given from the optical pickup during reproduction, and a wobble envelope signal representing an envelope of the wobble signal based on the shape of the recording track of the recording medium from the reproduced signal. A first generation circuit for generating, and the optical pickup for the recording track from the reproduced signal; A second generation circuit for generating a tracking error signal based on the tracking position of the optical disk and a system control circuit for controlling the optical disc apparatus, and the system control circuit performs tracking servo control for the optical pickup with respect to the recording track. When the frequency of the wobble envelope signal generated by the first generation circuit is substantially equal to the frequency of the tracking error signal generated by the second generation circuit in a state where the recording medium is not, the recording medium is a DVD- When the optical disc is determined to be an RW optical disc, and the frequency of the wobble envelope signal generated by the first generation circuit is approximately twice the frequency of the tracking error signal generated by the second generation circuit Determines that the recording medium is a DVD-RAM optical disk, and It is characterized in that to perform.

  The present invention also relates to an optical disc apparatus for recording / reproducing signals using an optical pickup using at least two types of optical discs, DVD-RAM and DVD-RW, on which recording tracks having a shape having periodic fluctuations are formed in advance. An optical disc determination method for an optical disc apparatus that performs the optical pickup without performing tracking servo control on the recording track, wherein the wobble signal is based on the shape of the recording track of the recording medium from the signal reproduced from the optical pickup. A first generating step for generating a wobble envelope signal representing an envelope of the recording medium; and a second generating step for generating a tracking error signal based on a tracking position of the optical pickup with respect to the recording track from a signal reproduced from the optical pickup. Generation steps When the frequency of the wobble envelope signal generated in the first generation step is substantially equal to the frequency of the tracking error signal generated in the second generation step, the recording medium is a DVD-RW optical disc. If the frequency of the wobble envelope signal generated in the first generation step is approximately twice the frequency of the tracking error signal generated in the second generation step, The recording medium has a determination step of determining that the recording medium is a DVD-RAM optical disk.

  According to the present invention, it is possible to provide an optical disc apparatus that shortens the time required for discriminating the type of an optical disc loaded, and an optical disc discrimination method for the optical disc apparatus, and can contribute to improvement in usability of the apparatus. There is.

1 is a block diagram of an optical disc apparatus showing an embodiment of the present invention. It is a wave form diagram of the reproduction signal in one Example of this invention. It is a circuit block diagram of a wobble detection signal generation circuit in an embodiment of the present invention. It is a circuit block diagram of a TZC signal generation circuit in one embodiment of the present invention. It is a flowchart of the optical disk discrimination | determination method of the optical disk apparatus in one Example of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of an optical disc apparatus showing an embodiment of the present invention, and mainly shows components related to an optical disc discrimination method according to the present invention. First, the operation will be described with reference to FIG.

  The optical disk 1 is fixed by a disk stopper 11 and is driven to rotate by a spindle motor 13 via a rotating shaft 12. The spindle motor 13 includes an FG 14 that generates an FG (Frequency Generator) pulse synchronized with the rotation thereof, and is fixed to the base 15 of the apparatus.

  The optical pickup 2 is provided with a screw in a part of the outer casing 26, and is guided by the rotation of the screw 62 directly connected to the rotation shaft of the thread motor 61, and can be positioned at an arbitrary position in the radial direction of the optical disk 1. . The objective lens 24 is finely adjusted by the actuator 23 in the radial direction of the optical disk, for example, using electromagnetic force, and finely adjusted in the distance and inclination with respect to the optical disk 1.

  The laser light generated by the laser light generator 21 is reflected by the beam splitter 22 and forms an image on the optical disc 1 through the objective lens 24. Modulated recording information possessed by the laser beam is recorded at the time of recording, and information recorded on the optical disc 1 is reproduced at the time of reproduction. The reflected light from the optical disk 1 passes through the objective lens 24 and the beam splitter 22 and is converted into an electric signal by the photodetector 25. The converted signal is given to an AFE (Analogue Front End) circuit 4.

  DVD-RAM or DVD-RW has grooves (valleys) and lands (mountains) on the recording surface of the optical disk. Therefore, the optical pickup 2 can be moved along a predetermined recording track even in an unused state. According to the standard, recording tracks are formed on both grooves and lands in DVD-RAM, and only on grooves in DVD-RW. Both the DVD-RAM groove and land, and the DVD-RW groove have undulations with a fine period. The optical detector 25 of the optical pickup 2 detects the optical signal reflected from the groove or land with two (or more) detectors positioned so as to sandwich the recording track. The push-pull signal processing circuit 42 generates a push-pull signal from these difference components.

  The generated push-pull signal includes a relatively high frequency wobble signal corresponding to the waviness period, and a low frequency tracking error signal (hereinafter referred to as TE signal) caused by eccentricity when the optical disk 1 rotates. (Abbreviated as “)”. The LPF 43 removes the wobble signal and extracts the TE signal. The BPF 45 has a relatively low low cut-off frequency and a high cut-off frequency higher than the LPF 43, and extracts a wobble signal by removing the TE signal and out-of-band noise from the push-pull signal. The TZC generation circuit 44 and the wobble envelope signal generation circuit 46 will be described later.

  In the system control circuit 5, first, focus servo control is performed so that the optical pickup 2 faces the optical disc 1 at an optimum distance. If necessary, tilt control is performed so as to face the optical disc 1 with an optimum inclination. Further, based on the extracted TE signal, the actuator 23 performs tracking servo control so that the objective lens 24 traces the center of the recording track. An operation for controlling the radial position of the entire optical pickup 2 on the optical disc 1 via the sled motor 61 and an operation for controlling the rotation of the optical disc 1 based on the FG pulse from the FG 14 by starting the spindle motor 13 are also included. This is performed by the system control circuit 5.

The output of the photodetector 25 is also supplied to the equalization circuit 41 of the AFE circuit 4. Here, the frequency characteristics accompanying recording / reproduction on the optical disc 1 are compensated, and after waveform equalization, it is given to the demodulation circuit 31 of the reproduction circuit 3. Here, the data modulated based on the playback clock is strobed, the modulation applied at the time of recording is canceled and demodulated as playback data, and errors that occur during the recording and playback process are corrected before playback. Processing such as data compression given to the processing circuit 32 and given at the time of recording is canceled and outputted to the output terminal 33 as a reproduction information signal.
In FIG. 1, the reproduction circuit 3, the AFE circuit 4, and the system control circuit 5 are not separated circuits, but are often implemented by high density mounting by using a DSP (Digital Signal Processor) housed in one semiconductor chip. .

Next, a method for discriminating between DVD-RAM and DVD-RW in the present invention will be described with reference to FIG. FIG. 2 is a waveform diagram of a reproduction signal in one embodiment of the present invention.
When the optical disk is mounted, the optical disk apparatus first performs focus servo control and, if necessary, tilt control, thereby causing the optical disk 1 and the optical pickup 2 to face each other at an optimum distance and angle. Next, before performing the tracking servo control, the type of the optical disk 1 as determined in the present invention is determined. As described above, at first, it is discriminated whether it is a DVD-RAM or a DVD-RW based on the light reflectance. However, at this stage, the present invention is either a DVD-RAM or a DVD-RW. If it is, it is for determining which one of them.
First, the optical pickup 2 irradiates the optical disc 1 with laser light without being subjected to tracking servo control. Then, since a plurality of tracks, that is, a groove and a land are crossed, a large variation is detected in the above-described TE signal and wobble signal.

  FIG. 2 shows the waveforms of the TE signal and the wobble signal in this state, where (a) shows a DVD-RAM and (b) shows a DVD-RW. The wobble signal is enveloped by an envelope having a low frequency fluctuation and is detected as a signal having a much shorter period than the TE signal. As shown in the figure, since the TE signal has a waveform corresponding to the unevenness due to the grooves and lands, a signal having one cycle is detected every time the pair of grooves and lands are crossed. On the other hand, in the wobble signal, a signal having one cycle is detected every time the envelope crosses one recording track. As described above, the recording track is formed on both the groove and the land in the DVD-RAM, and the recording track is formed only on the groove in the DVD-RW. For this reason, the envelope of the wobble signal is maximized at the center of both the groove and the land in the former and at the center of the groove in the latter. Therefore, in the DVD-RAM, the period of the envelope of the wobble signal is twice that of the TE signal, but in the DVD-RW, both coincide.

  In the present invention, by using a determination method that makes use of this feature, for example, as described above, the operation of reciprocating between the RAM area and the ROM area on the optical disk is unnecessary, and the type of the mounted optical disk is determined. It is characterized by shortening the time required. Although the actual effect on shortening the rise time varies depending on the apparatus, it is approximately 0.5 seconds, which can contribute to improvement in operability.

Next, a circuit for detecting the envelope frequency of the wobble signal will be described with reference to FIG. FIG. 3 is a circuit block diagram of a wobble envelope signal generation circuit according to an embodiment of the present invention, which corresponds to 46 in FIG.
The wobble signal from the BPF 45 in FIG. 1 is given to the wobble envelope signal generation circuit 46. This signal is input from the input terminal 461 in FIG. 3, and the top envelope detection circuit 462 detects the upper envelope of the wobble signal in FIG. Further, the bottom envelope detection circuit 463 detects the lower envelope of the wobble signal in FIG. These can be easily implemented with a known amplitude detector or the like. Next, the DC signal is removed from the difference signal obtained by subtracting both by the differential amplifier 464 by the capacitor C, the center DC voltage is given by the reference voltage circuit 465 through the resistor R, and the differential amplifier 466 Compared to the reference voltage. In this manner, a wobble envelope detection signal can be obtained as a binarized signal at the output terminal 467. This signal is given to the frequency comparison circuit 51 of the system control circuit 5 in FIG. The wobble envelope detection signal indicates whether or not the wobble signal is equal to or higher than a predetermined value, and the frequency thereof is a frequency at which the optical pickup 2 crosses the recording track.

Next, a circuit for detecting the frequency of the TE signal will be described with reference to FIG. FIG. 4 is a circuit block diagram of a TZC (Tracking Zero Cross) signal generation circuit in one embodiment of the present invention, which corresponds to 44 in FIG.
The TE signal from the LPF 43 in FIG. 1 is given to the TZC signal generation circuit 44. This signal is input from the input terminal 441 in FIG. 4, the DC component is removed by the capacitor C, the center DC voltage is given by the reference voltage circuit 442 through the resistor R, and compared with the previous reference voltage by the differential amplifier 443. Is done. As a result, a TZC signal can be obtained as a binarized signal at the output terminal 445. Naturally, it coincides with the period of the TE signal. This signal is given to the frequency comparison circuit 51 of the system control circuit 5 in FIG. The system control circuit 5 controls the optical pickup 2 using this signal when performing the tracking servo control described above.

  In the frequency comparison circuit 51, the frequencies of the wobble envelope detection signal and the TZC signal are compared. The system control circuit 5 discriminates DVD-RAM if the former frequency is almost twice the latter frequency, and DVD-RW if the both frequencies are almost equal. For example, the laser intensity in the laser light generator 21 is determined. The entire optical disc apparatus is controlled, for example, adjusted to the optimum value for each type of optical disc.

Next, the operation flow of the present invention will be described with reference to FIG. FIG. 5 is a flowchart of the optical disc discrimination method of the optical disc apparatus in one embodiment of the present invention.
After the optical disc 1 is mounted on the optical disc apparatus, the system control circuit 5 drives the sled motor 61 to move the optical pickup 2 to the RAM area of the optical disc 1 in step S500. Next, in step S501, the system control circuit 5 performs focus servo control on the optical pickup 2 and adjusts the distance and inclination of the optical pickup 2 with respect to the optical disc 1 to be optimum. Further, it is assumed that the optical disk 1 is discriminated as a DVD-RAM or a DVD-RW from the reflectance of the laser beam. The system control circuit 5 causes the optical pickup 2 to cross a plurality of recording tracks using the eccentricity of the optical disc 1 without performing tracking servo control yet.

In step S502, the system control circuit 5 receives the wobble envelope detection signal from the wobble envelope signal generation circuit 46, and stores its frequency in a memory (not shown, may be incorporated in the system control circuit 5 or externally attached). To store.
In step S503, the system control circuit 5 receives the TZC signal from the TZC signal generation circuit 44 and stores the frequency in the memory.

In step S504, the system control circuit 5 compares the two frequencies stored in the memory. In step S505, it is determined whether both frequencies are substantially equal or whether the wobble envelope detection signal is approximately twice as high as the TZC signal.
If approximately equal, the system control circuit 5 determines in step S506 that the loaded optical disk is a DVD-RW, generates a control signal, and controls the components of the optical disk related to the type of the disk. If the wobble envelope detection signal is approximately twice as high as the TZC signal, the system control circuit 5 determines in step S507 that the loaded optical disk is a DVD-RAM, generates a control signal, and sets the type of the disk. Control the components of the optical disc involved.

  Note that the expression of approximately equal to or approximately twice the frequency is used, which takes into account frequency measurement errors. In principle, they should be exactly the same or exactly double, but in reality, an error occurs due to factors such as noise. For example, if the error is within 1 percent, it may be determined that they are equal or double.

  Further, in the case where the determination result in step S505 in FIG. 5 does not correspond to approximately equal or approximately twice, the influence from large noise or optical disk failure may be considered, so the flow from step S502 is performed again. And good. If a result that does not correspond to any of the above results is obtained for a predetermined number of times, it may be released because the optical disk is defective.

  In addition, the matter shown so far is one Example, and many modifications can be considered. For example, in FIGS. 3 and 4, the output signal at the output terminal is a binary signal, but the operation can be performed without using the binary signal, and the present invention is not limited to this. Thus, although the example which gave the change can be considered even if it is the range which does not change the meaning of this invention, all are in the category of this invention.

DESCRIPTION OF SYMBOLS 1 ... Optical disk 13 ... Spindle motor 14 ... FG
2... Optical pickup 21... Laser light generator 22... Beam splitter 23... Actuator 24.・ Reproduction circuit 31... Demodulation circuit 32... Reproduction processing circuit 4... AFE circuit (arithmetic circuit)
41... Equalization circuit 42... Push-pull signal processing circuit 44... TZC generation circuit 46... Wobble envelope signal generation circuit 5. Frequency comparison circuit 61... Thread motor.

Claims (4)

An optical disc apparatus using as a recording medium at least two types of optical discs, a DVD-RAM and a DVD-RW, in which recording tracks having a shape having periodic fluctuations are formed,
An optical pickup for recording a signal on the recording medium using a laser beam and reproducing the signal based on the reflected light of the laser beam from the recording medium;
A signal processing circuit for processing the signal at the time of recording and supplying the signal to the optical pickup, and processing the signal from the optical pickup at the time of reproduction;
A first generation circuit for generating a wobble envelope signal representing an envelope of the wobble signal based on the shape of the recording track of the recording medium from the reproduced signal;
A second generation circuit that generates a tracking error signal based on the tracking position of the optical pickup with respect to the recording track from the reproduced signal;
A system control circuit for controlling the optical disc device;
The system control circuit is in a state where the optical pickup is not subjected to tracking servo control with respect to the recording track.
When the frequency of the wobble envelope signal generated by the first generation circuit is substantially equal to the frequency of the tracking error signal generated by the second generation circuit, the recording medium is a DVD-RW optical disc. Judge that there is,
When the frequency of the wobble envelope signal generated by the first generation circuit is approximately twice the frequency of the tracking error signal generated by the second generation circuit, the recording medium is a DVD-RAM. It is determined that the optical disc is
An optical disc apparatus that performs the control.   2. The optical disk device according to claim 1, wherein the system control circuit performs the determination again when it is determined that the recording medium does not correspond to either DVD-RW or DVD-RAM. apparatus.   3. The optical disk device according to claim 2, wherein when the system control circuit determines that the recording medium does not correspond to either DVD-RW or DVD-RAM, the system control circuit determines that the recording medium corresponds to either one or a predetermined The optical disc apparatus is characterized in that the determination is repeated until the number of times is reached. The optical pickup in an optical disc apparatus for recording and reproducing signals using an optical pickup using at least two types of optical discs of a DVD-RAM and a DVD-RW on which recording tracks having a shape having periodic fluctuations are formed. An optical disc determination method for an optical disc apparatus performed without tracking servo control for the recording track,
A first generation step of generating a wobble envelope signal representing an envelope (envelope) of a wobble signal based on a shape of the recording track of the recording medium from a signal reproduced from the optical pickup;
A second generation step of generating a tracking error signal based on a tracking position of the optical pickup with respect to the recording track from a signal reproduced from the optical pickup;
When the frequency of the wobble envelope signal generated in the first generation step is substantially equal to the frequency of the tracking error signal generated in the second generation step, the recording medium is a DVD-RW optical disc. If the frequency of the wobble envelope signal generated in the first generation step is approximately twice the frequency of the tracking error signal generated in the second generation step, the recording is performed. An optical disc determination method for an optical disc apparatus, comprising: a determination step of determining that the medium is a DVD-RAM optical disc.

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