JP2006031779A - Optical disk device and disk discriminating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device and a disk discriminating method in which a disk can be smoothly and speedily discriminated by simple processing. <P>SOLUTION: A disk discrimination is performed based on a SUM signal corresponding to a quantity of reflection light, a frequency (zero-cross point interval T) of a radial push and pull (RPP) signal and an amplitude value A. Concretely, if the zero-cross point interval T is a threshold T1 or less, a disk is discriminated as HDVD and if the interval T exceeds the threshold T1, the disk is discriminated as DVD or CD (S110, S112). If the result of the discrimination indicates DVD or CD based on the amplitude value A of the RPP signal and the SUM signal, the result is more precisely divided (S113). Concretely, in the case of A>A1 and A<A2, it is discriminated as DVD±R, in the case of A>A1 and A≥A2, it is discriminated as DVD±RW, in the case of A≤A1, SUM>S2 and SUM≥S1, it is discriminated as DVD-ROM, in the case of SUM<S1, it is discriminated as CD and in the case of A>A1 and SUM≤S2, it is discriminated as DVD-RAM. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical disc apparatus and disc discriminating method, and is particularly suitable for use in an optical disc apparatus for recording and / or reproducing compatible discs of different types.

  Currently, various optical discs such as CD (Compact Disc) and DVD (Digital Versatile Disc) have been commercialized and spread. Furthermore, recently, standardization of a next-generation DVD (hereinafter referred to as “HDDVD” for convenience) in which information is recorded / reproduced using blue-violet laser light is being promoted. Such an HDDVD records and reproduces information using a blue-violet laser beam having a wavelength of about 405 nm. A further increase in density can be achieved by shortening the wavelength of the laser beam.

  In an optical disc apparatus that records and / or reproduces these discs in a compatible manner, a means for discriminating which type the disc is in is required. Here, as one of the discriminating means, a method of reading disc type information recorded on the disc can be used. However, in this case, it is necessary to repeat the reading operation while changing the wavelength, which complicates the processing and prolongs the determination time.

Therefore, in Patent Document 1 below, depending on whether the peak-to-peak value of the tracking error signal when the beam is moved in the disk radial direction is larger than a reference value, CD (low density disk) and DVD (high density disk) are used. Discrimination is performed. According to this, since it is not necessary to read the disc type information, the discrimination process can be simplified and speeded up.
JP 11-250558 A

  However, in the invention of Patent Document 1, it is possible to discriminate between CD and DVD, but it is not possible to discriminate discs included in the DVD category in detail. The DVD category includes DVD-R (Recordable), RW (Re-Writable), ROM (Read Only Memory), and RAM (Random Access Memory), and the control is different for each disk. For this reason, when the disc is loaded, it is necessary to discriminate the disc type finely and switch the control. In the invention of Patent Document 1, although it is discriminated that it is a DVD, it cannot be discriminated in detail which type of disc, and eventually it is necessary to read disc identification information from the disc, which hinders speeding up of processing. Arise.

  In addition, in the invention of Patent Document 1, since the disc is discriminated by irradiating the disc with a CD laser beam having a large wavelength, a tracking error signal is generated satisfactorily when the disc loaded is a DVD. There is a possibility that it cannot be done. This point becomes prominent when a higher-density HDDVD is mounted. In this case, the tracking error signal waveform may be crushed.

Therefore, an object of the present invention is to provide an optical disc apparatus and disc discriminating method capable of discriminating smoothly and quickly with simple processing.

  In view of the above problems, the present invention has the following features.

  The first invention relates to an optical disk apparatus, an optical pickup for irradiating the disk with laser light, focus control means for controlling the focus of the laser light on the disk, and radial push receiving the return light from the disk. A signal generation unit that generates and outputs a pull signal; and a disk determination unit that determines a disk type based on a push-pull signal from the signal generation unit. The disk determination unit focuses laser light having a predetermined wavelength on the disk. The disc type is discriminated based on the amplitude value of the push-pull signal output from the signal generating means when the signals are combined.

  According to the present invention, for example, DVD-R and RW can be discriminated smoothly from a group of discs included in the DVD category.

  The second invention relates to an optical disc apparatus, which is an optical pickup that irradiates a disc with laser beams of different wavelengths, a focus control means that performs focus control of the laser beam on the disc, and receives return light from the disc. Signal generating means for generating and outputting a radial push-pull signal and disk discriminating means for discriminating the disc type based on the push-pull signal from the signal generating means, wherein the disc discriminating means emits laser light of a predetermined wavelength. The disc type is discriminated based on the period and amplitude value of the push-pull signal output from the signal generating means when focusing on the disc.

  Here, the disc discriminating unit performs, for example, a first discrimination based on a period of the push-pull signal, and further, the push-pull with respect to a disc group included in the disc type discriminated by the first discrimination. The second determination can be performed based on the amplitude value of the signal.

  According to the present invention, for example, DVD and HDDVD can be classified by the first discrimination, and further, DVD-R and RW are discriminated among the disc groups included in the DVD category by the second discrimination. be able to.

  A third invention relates to an optical disk apparatus, and includes an optical pickup for irradiating a disk with laser beams of different wavelengths, focus control means for performing focus control of laser light on the disk, and receiving return light from the disk. Based on the signals from the light quantity detecting means for outputting a signal corresponding to the light quantity, the signal generating means for receiving the return light from the disc and outputting a radial push-pull signal, and the signals from the light quantity detecting means and the signal generating means. A disc discriminating unit for discriminating a disc type, and the disc discriminating unit outputs a magnitude of a signal output from the light amount detecting unit when a laser beam having a predetermined wavelength is focused on the disc, and an output from the signal generating unit. The disc type is discriminated based on the amplitude value of the push-pull signal.

  Here, the disc discriminating unit performs, for example, a first discrimination based on the amplitude value of the push-pull signal, and further, the light amount for the disc group included in the disc type discriminated by the first discrimination. The second determination can be performed based on the magnitude of the signal output from the detection means.

  According to the present invention, for example, DVD-R and RW can be discriminated from the disc group included in the DVD category by the first discrimination, and the remaining DVD-ROM and DVD-RAM can be discriminated. By the second discrimination, it can be discriminated whether it is a DVD-ROM or a DVD-RAM.

  The fourth invention relates to an optical disk apparatus, and is an optical pickup for irradiating a disk with laser beams of different wavelengths, focus control means for controlling the focus of the laser light on the disk, and receiving return light from the disk. Based on the signals from the light quantity detecting means for outputting a signal corresponding to the light quantity, the signal generating means for receiving the return light from the disc and outputting a radial push-pull signal, and the signals from the light quantity detecting means and the signal generating means. A disc discriminating unit for discriminating a disc type, and the disc discriminating unit outputs a magnitude of a signal output from the light amount detecting unit when a laser beam having a predetermined wavelength is focused on the disc, and an output from the signal generating unit. Disc type is determined based on the period and amplitude value of the push-pull signal To.

  Here, the disc discriminating unit performs, for example, a first discrimination based on the period of the push-pull signal, and the push-pull signal of the disc group included in the disc type discriminated by the first discrimination is determined. A second determination is made based on the amplitude value, and a third determination is made based on the magnitude of the signal output from the light amount detection means for the disk group included in the disk type determined by the second determination. Can be done.

  According to the present invention, for example, DVD and HDDVD can be classified by the first discrimination, and DVD-R, RW among the disc groups included in the DVD category can be discriminated by the second discrimination. Further, it can be determined by the third determination whether the remaining DVD-ROM or RAM is left.

  In the above invention, the disc discriminating unit may discriminate the disc by irradiating the disc with a laser beam having the shortest wavelength among the laser beams that can be applied to the disc. More specifically, the disc may be discriminated by irradiating the disc with blue-violet laser light. In this way, the push-pull signal can be generated satisfactorily in any disk, so that the disk can be discriminated smoothly.

  In the above invention, the disc discrimination means may discriminate the disc by irradiating the disc with a laser beam having a predetermined wavelength while rotating the disc. In this way, it is possible to suppress the local concentration of the laser light power on the disk, and when the loaded disk is a recordable disk, erroneous recording is caused by laser light irradiation at the time of disc identification. It can be prevented from occurring.

  Furthermore, in the above invention, it is preferable that the disc discriminating unit discriminates the disc based on the push-pull signal when the laser beam is moved in the radial direction with respect to the disc. In this way, a stable push-pull signal can be generated, and disc misidentification can be prevented.

  To further explain this point, when the disk is rotated, the laser beam is not moved in the radial direction with respect to the disk, but due to the influence of the eccentricity of the disk (there is eccentricity due to mounting and eccentricity at the time of manufacturing the disk), etc. A cross track of the beam occurs and a push-pull signal is generated. However, if the eccentricity of the disk is large, even if the disk has a large track pitch, the push-pull signal cycle becomes small, and as a result, there is a possibility that the disk is erroneously identified as a disk having a small track pitch. On the other hand, if the eccentricity of the disk is extremely small, the period of the push-pull signal cannot be read, and the disk may not be discriminated. As described above, when disc discrimination is performed by relying only on the eccentricity of the disc, there arises a problem that the degree of disc eccentricity affects the discrimination accuracy.

  On the other hand, when the laser beam is moved in the disk radial direction as described above, a stable push-pull signal can be generated corresponding to the disc to be discriminated. As a result, it is possible to prevent problems such as disc misidentification or inability to discriminate as described above.

  In each of the above inventions, the disc type is determined more specifically by setting the signal magnitude according to the amount of light returned from the disc, the period of the radial push-pull signal, and the amplitude value according to the disc type. Compared with the threshold value, the disk type can be specified based on the magnitude relationship. Here, the threshold value is set to a value that allows the magnitude, period, and amplitude value of these signals to be measured and verified in advance with respect to a compatible disk, and to determine the disk type smoothly and appropriately based on the verification result.

  Note that the measurement / verification for CD, DVD, and HDDVD is performed by the present inventors, and is shown together with the threshold value in the following embodiments.

The present invention can be grasped as an aspect of the “disc discriminating method” in addition to the aspect as the “optical disc apparatus” described above.

  According to the present invention, the disc type is discriminated based on the magnitude of the signal corresponding to the return light quantity from the disc and the period and amplitude value of the radial push-pull signal, so that existing optical components and circuit configurations can be used as they are. While being used, disc discrimination can be performed easily and smoothly.

  In particular, by using a new method of discriminating the disc type based on the amplitude value of the push-pull signal, for example, discs in the DVD category can be discriminated more precisely. A predetermined disk can be specified from the inside.

The characteristics or significance of the present invention will be further clarified by the following description of embodiments. However, the following embodiment is an example of the present invention, and the meaning of the term of the present invention or each constituent element is not limited to what is described in the following embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that this embodiment exemplifies a case where the present invention is applied to an optical disc apparatus (recording / reproducing apparatus) compatible with CD, DVD, and HDDVD.

  FIG. 2 shows a configuration of the optical disc apparatus according to the embodiment.

  As shown, the optical disc apparatus includes an encoder 101, a modulation circuit 102, a laser drive circuit 103, a laser power adjustment circuit 104, an optical pickup 105, a signal generation circuit 106, a demodulation circuit 107, a decoder 108, The servo circuit 109 and the controller 110 are included.

  The encoder 101 performs encoding processing such as addition of an error correction code on the input recording data, and outputs it to the modulation circuit 102. The modulation circuit 102 performs predetermined modulation on the input recording data, further generates a recording signal, and outputs the recording signal to the laser driving circuit 103.

  The laser drive circuit 103 outputs a drive signal corresponding to the recording signal from the modulation circuit 102 during recording for CD (infrared: wavelength 780 nm), DVD (red: wavelength 650 nm), and HDDVD (blue purple: wavelength 405 nm). Among them, the laser beam is output to the corresponding semiconductor laser 105a, and at the time of reproduction, a driving signal for emitting a laser beam having a constant intensity is output to the corresponding semiconductor laser 105a. Here, the laser power is adjusted and set by the laser power adjustment circuit 104.

  The laser power adjustment circuit 104 sets and adjusts the laser power in accordance with a command from the controller 110. In the disc discrimination processing, adjustment is made so that the laser beam at the reproduction power level is output to the semiconductor laser 105a for HDDVD.

  The optical pickup 105 includes a semiconductor laser 105a and a photodetector 105b, and further includes an objective lens actuator (not shown) for adjusting the irradiation state of the laser beam to the track, and the laser beam emitted from the semiconductor laser 105a. An optical system (not shown) for guiding the reflected light from the disk 100 to the photodetector 105b is provided.

  The semiconductor laser 105a is composed of three semiconductor lasers that emit laser light for CD (infrared: wavelength 780 nm), DVD (red: wavelength 650 nm), and HDDVD (blue purple: wavelength 405 nm), respectively. These semiconductor lasers may be accommodated in the same CAN, or may be individually accommodated in three independent CANs and individually disposed on the base of the optical pickup 105. The configuration and arrangement of the optical system is appropriately changed according to the configuration of the semiconductor laser.

  The objective lens among the components constituting the optical system is designed so that the laser beam for HDDVD can be properly converged on the disc. The optical system uses an aberration correction element (diffraction element, phase correction element, etc.) for suppressing aberrations that occur when using DVD laser light and CD laser light, and CD laser light. In some cases, a numerical aperture limiting element (liquid crystal shutter, diffraction element, etc.) for limiting the numerical aperture with respect to the objective lens is included.

  The signal generation circuit 106 amplifies and arithmetically processes the signal received from the photodetector 105b to generate various signals and outputs them to the corresponding circuit.

  The signal generation circuit 106 subtracts and amplifies signals from a pair of optical sensors that detect the reflected beam intensity distribution in the radial direction (disk radial direction) to generate a radial push-pull signal (hereinafter referred to as “RPP signal”). A circuit for extracting a low-frequency component of the RPP signal to generate a tracking error signal, and a circuit for extracting a high-frequency component of the RPP signal to generate a wobble signal.

  The signal generation circuit 106 includes a circuit that adds signals from all sensors that receive the reflected beam and generates and outputs a signal (SUM signal) corresponding to the amount of reflected light. In addition, a circuit for generating a focus error signal by processing the signal from the optical sensor is provided. The SUM signal only needs to be derived according to the amount of reflected light. In addition to being generated by adding signals from all sensors as described above, the output from a predetermined sensor among all sensors is added. May be generated.

  The demodulation circuit 107 demodulates the reproduction RF signal input from the signal generation circuit 106 to generate reproduction data, and outputs the reproduction data to the decoder 108. The decoder 108 performs decoding processing such as error correction on the data input from the demodulation circuit 107 and outputs the result to a subsequent circuit.

  The servo circuit 109 generates a focus servo signal and a tracking servo signal from the focus error signal and tracking error signal input from the signal generation circuit 106 and outputs them to the objective lens actuator of the optical pickup 105. Further, a motor servo signal is generated from the synchronization detection signal or wobble signal input from the signal generation circuit 106 and output to the disk drive motor.

  The controller 110 stores various data in the built-in memory and controls each unit according to a preset program.

  FIG. 2 shows a process flowchart in the disk discrimination process. Note that this disc determination process is performed, for example, at the timing when the disc is loaded into the optical disc apparatus.

  When the processing flow is started, first, the optical pickup 105 is moved to a predetermined radial position (for example, a position having a radius of 25 mm which is a CD program start position) (S101), and the disk is rotated at a predetermined speed (S102). ). Next, among the semiconductor lasers 105a, the semiconductor laser that emits the laser beam for HDDVD is turned on at the reproduction power level, and at the same time, the optical system (aberration correction element, aperture limiting element, etc.) is set to the HDDVD reproduction mode. (S103).

  Thereafter, the focus servo pull-in operation is started, and the value of the SUM signal at the focus ON timing is acquired by the controller 110 (S105). Specifically, as shown in FIG. 4, the SUM signal at the zero cross position of the focus error signal is acquired.

  Next, the laser beam is moved at a constant speed in the disk radial direction (S106). Such movement is performed by moving the objective lens in the disk radial direction. For example, it is performed by applying a driving signal corresponding to the speed to the objective lens driving actuator, or by applying a driving signal to a sled motor that sends the optical pickup 105 in the radial direction. This movement is preferably performed not in the lead-in area direction but in the program area direction, that is, in the disk outer peripheral direction.

The moving speed may be set to a speed sufficiently faster than the speed at which the beam moves in the radial direction by a distance corresponding to the maximum eccentricity while the disk is rotated halfway. Specifically, in HDDVD, the linear velocity is increased to about 5 to 6 m / s, and the time required for one rotation at the innermost circumference r = 25 mm is 31 ms (in the case of a linear velocity of 5 m / s). The core amount can be estimated to be within a maximum of 0.3 mm. So in this case,
Average moving speed> 0.3 / (31/2) = 0.019m / s
Therefore, for example, the beam may be moved in the radial direction at 0.1 m / s which is sufficiently faster than this.

  Accordingly, when the laser light is moved in the disk radial direction, an RPP signal is generated by the signal generation circuit 106 in accordance with this and is input to the controller 110. At this time, as shown in FIG. 5, the RPP signal has a different signal cycle (zero cross point interval T) depending on whether the loaded disc is a DVD or a HDDVD having a higher density than that. When the loaded disc is a CD, the zero cross point interval T is further larger than the zero cross point interval of the DVD in FIG. The controller 110 first measures the zero-cross point interval T of the RPP signal (S107), and further measures the amplitude A (Peak-to-Peak) of the RPP signal (S108). When such measurement is finished, the movement of the laser light is finished (S109).

  Thereafter, the controller 110 first determines whether the measured zero-cross point interval T is equal to or less than the threshold value T1 (S110). If it is equal to or less than the threshold T1 (S110: Y), it is determined that the disc is an HDDVD (S111). If it is equal to or greater than the threshold T1 (S110: N), it is determined that the disc is a DVD or a CD. (S112). Note that the threshold value T1 is set to a value capable of separating DVD, CD, and HDDVD.

  Specifically, the track pitch of the current CD is 1.6 μm, the DVD is 0.74 μm, and the next-generation DVD is proposed to be about 0.32 to 0.4 μm. Is moved in the radial direction, the threshold value T1 may be about 3.5 μs.

  When obtaining the zero-cross point interval, the beam is moved several times by reciprocating the beam in the radial direction, etc., and the minimum zero-cross point interval is obtained from the zero-cross point intervals obtained at that time. Acquired as the zero cross point interval. If the zero-cross point interval thus obtained is compared with the threshold value T1, the measurement error can be effectively reduced.

  If the disc is discriminated as a DVD or CD from the discriminating result in S110 (S112), the disc is any one of DVD-R, RW, ROM, and RAM based on the amplitude value A of the RPP signal and the SUM signal. Or a CD is discriminated (S113). Hereinafter, the details of the processing in S113 will be described with reference to FIG.

  In this determination, first, it is determined whether the amplitude value A of the RPP signal is equal to or less than the threshold value A1 (S201). Here, if it is equal to or less than the threshold A1 (S201: Y), it is next determined whether the SUM signal is equal to or less than the threshold S2 (S202). If it is equal to or less than the threshold value S2 (S202: Y), it is determined that the disc is a DVD-RAM (S203). If the threshold value S2 is exceeded (S202: N), it is further determined whether the SUM signal is equal to or greater than the threshold value S1 (S1> S2: see FIG. 4) (S204). If the threshold is S1 or more (S204: Y), the disc is discriminated as a DVD-ROM (S205). If the disc is smaller than the threshold S1 (S204: N), the disc is a CD (CD-ROM / R, etc.). ) (S206).

  On the other hand, if it is determined in S201 that the amplitude value A exceeds the threshold A1, it is then determined whether the amplitude value A is equal to or greater than the threshold A2 (S207). If the amplitude value A is equal to or greater than the threshold value A2 (S207: Y), the disc is determined to be DVD ± RW (S208), and if the amplitude value A is smaller than the threshold value A2 (S207: N). The disc is discriminated to be DVD ± R (S209).

  FIG. 6 shows a verification result obtained by verifying the relationship between the amplitude value (Peak-to-Peak) of the RPP signal and the value of the SUM signal for each disk and each manufacturer.

  As shown in the figure, there is a gap of about 200 mV in the RPP signal between DVD-ROM, RAM and DVD ± R, and there is a gap of about 300 mV in the RPP signal between DVD ± R and DVD ± RW. You can see that there is an opening. Therefore, in the processing flow of FIG. 3, the threshold value A1 is set to about 200 mV, which is an intermediate value of the RPP signal amplitude values of DVD-ROM, RAM and DVD ± R, and the threshold value A2 is set to DVD ± R and DVD ± RW. By setting the intermediate value of the RPP signal amplitude value to about 450 mV, the DVD-ROM, RAM, DVD ± R, and DVD ± RW can be classified in the comparison processing of S201 and S207.

  Further, as shown in the figure, the DVD-ROM and DVD-RAM are close to each other in the amplitude value of the RPP signal, but a large gap is seen in the SUM signal. Therefore, in the processing flow of FIG. 3, the threshold value S2 is set to, for example, about 1.0 V according to the difference of the SUM signal, so that the DVD-ROM and the DVD-RAM are distinguished in the processing of S202. can do.

  As shown in the figure, the amplitude value of the CD RPP signal is about 50 to 80 mV, and the magnitude of the SUM signal is about 2.0 to 2.9 V. When the threshold value S2 is set, the disc determined as SUM signal> threshold value S2 (S202: N) in S202 includes two types of DVD-ROM and CD. However, as shown in FIG. 6, the DVD-ROM and the CD have a difference in the magnitude of the SUM signal. Therefore, if the threshold value S1 is set to about 3.5 V, for example, according to the difference between the SUM signals. In the process of S204, the DVD-ROM and the CD can be distinguished.

  As described above, according to the present embodiment, CD, DVD, and HDDVD can be smoothly identified from the value of the SUM signal, the period of the RPP signal (zero cross point interval T), and the amplitude value A. Further, by adding the evaluation by the SUM signal to the amplitude value A of the RPP signal, DVD-ROM, RAM, R, RW and CD systems included in the DVD category can be smoothly classified.

  Note that HDDVD is still in the research process before commercialization, and therefore, the verification results are not shown in FIG. 6 in the above embodiment, but considering the material, the standard shape, etc., the amplitude value of the RPP signal and the SUM It can be predicted that the same tendency as in the case of DVD is observed in the signal value. Therefore, by setting an appropriate threshold value, it can be expected that the disk group included in the HDDVD category can be further divided as in the case of the DVD. Alternatively, after the disc is determined to be HDDVD, the disc identification information is read as it is with blue-violet laser light, and HDDVD-ROM, RW, etc. are discriminated and various controls are switched so that the playback mode is suitable for each disc. It is also possible to do.

  Note that, according to the present embodiment, the disc is discriminated using the SUM signal and the RPP signal that are used at the time of normal recording / reproduction, so there is no need to separately prepare a special configuration for disc discrimination. Therefore, the configuration is not complicated. According to the present embodiment, such an effect can be produced as a secondary effect.

  As mentioned above, although embodiment which concerns on this invention was described, it cannot be overemphasized that this invention is not limited to this embodiment, and various changes are possible.

  For example, in the above embodiment, an example in which the present invention is applied to an optical disk device compatible with CD, DVD, and HDDVD has been shown. However, the present invention is an optical disk device compatible with CD, DVD, optical disk device compatible with DVD, HDDVD, etc. The present invention can also be applied to an optical disk device in which the combination of compatible disks is changed. In this case, for example, in the case of a DVD or HDDVD compatible optical disc apparatus, the processing for discriminating the CD, that is, the processing of S204 and S206 in the flowchart shown in FIG. 3, is omitted. As described above, the steps of the flowcharts of FIGS. 2 and 3 are appropriately omitted according to the combination of compatible disks.

  The present inventor has already confirmed that discs such as DVD-ROMs and RWs that are DVD categories can be reproduced using an optical system for HDDVD using blue-violet laser light. By using this method, even if the disc is discriminated in the DVD category, it is possible to reproduce the disc without switching to the DVD laser beam, thereby further speeding up the processing.

  It should be noted that the present invention can also be applied to an optical disc apparatus that handles only DVD category discs. In this case, the processing steps necessary for CD determination and HDDVD determination, that is, the processing of S107, S110 and S111, and S204 and S206 in the processing flow of FIGS. 2 and 3 are omitted.

  In the above description, the DVD and the HDDVD are discriminated based on the period of the RPP signal (zero cross point interval T). However, it is possible to change the disc to discriminate between the DVD and the HDDVD by other methods. However, since the amplitude value A of the RPP signal is used for disc discrimination, it is advantageous for simplification of processing that the RPP signal is used for discriminating between DVD and HDDVD. Preferably, as described above, the RPP signal It is preferable to discriminate between DVD and HDDVD based on the period (zero cross point interval T).

In addition, the embodiment of the present invention can be variously modified as appropriate within the scope of the technical idea shown in the claims.

The figure which shows the structure of the optical disk apparatus which concerns on embodiment The figure which shows the processing flow at the time of the disc discrimination based on embodiment The figure which shows the detail of the process of S115 in the processing flow at the time of disc determination The figure explaining the production | generation method of the SUM signal which concerns on embodiment The figure which shows the state of the RPP signal which concerns on embodiment The figure which shows the example of verification which concerns on embodiment

Explanation of symbols

105 Optical Pickup 105a Semiconductor Laser 105b Photodetector 106 Signal Generation Circuit 109 Servo Circuit 110 Controller

Claims (19)

An optical pickup that irradiates a disk with laser light, a focus control means that performs focus control of the laser light on the disk, a signal generation means that receives return light from the disk and generates and outputs a radial push-pull signal, and the signal generation Disc discriminating means for discriminating the disc type based on the push-pull signal from the means,
The disc discriminating unit discriminates a disc type based on an amplitude value of a push-pull signal output from the signal generating unit when a laser beam having a predetermined wavelength is focused on the disc;
An optical disc device characterized by the above. An optical pickup that irradiates the disc with laser beams of different wavelengths, a focus control unit that performs focus control of the laser beam on the disc, a signal generation unit that receives the return light from the disc and generates and outputs a radial push-pull signal; Disc discriminating means for discriminating the disc type based on the push-pull signal from the signal generating means,
The disc discriminating unit discriminates a disc type based on a period and an amplitude value of a push-pull signal output from the signal generating unit when a laser beam having a predetermined wavelength is focused on the disc;
An optical disc device characterized by the above. 3. The disc determination unit according to claim 2, wherein the disc determination unit performs a first determination based on a period of the push-pull signal, and further, the push-pull signal for a disk group included in the disc type determined by the first determination. A second determination is made based on the amplitude value of
An optical disc device characterized by the above. An optical pickup that irradiates the disc with laser beams of different wavelengths, a focus control unit that performs focus control of the laser beam on the disc, a light amount detection unit that receives return light from the disc and outputs a signal according to the amount of light, A signal generation means for receiving a return light from the disk and outputting a radial push-pull signal; and a disk determination means for determining a disk type based on signals from the light amount detection means and the signal generation means,
The disk discriminating unit is configured to discriminate a disc based on the magnitude of a signal output from the light amount detecting unit and the amplitude value of a push-pull signal output from the signal generating unit when a laser beam having a predetermined wavelength is focused on the disc. Determine the type,
An optical disc device characterized by the above. 5. The disk determination unit according to claim 4, wherein the disk determination unit performs a first determination based on an amplitude value of the push-pull signal, and further detects the light amount for a disk group included in the disk type determined by the first determination. A second determination is made based on the magnitude of the signal output from the means;
An optical disc device characterized by the above. An optical pickup that irradiates the disc with laser beams of different wavelengths, a focus control unit that performs focus control of the laser beam on the disc, a light amount detection unit that receives return light from the disc and outputs a signal according to the amount of light, A signal generation means for receiving a return light from the disk and outputting a radial push-pull signal; and a disk determination means for determining a disk type based on signals from the light amount detection means and the signal generation means,
The disc discriminating unit is based on the magnitude of a signal output from the light amount detecting unit when a laser beam having a predetermined wavelength is focused on the disc, and the period and amplitude value of a push-pull signal output from the signal generating unit. Disc type
An optical disc device characterized by the above. 7. The disc determination unit according to claim 6, wherein the disc determination unit performs a first determination based on a cycle of the push-pull signal, and an amplitude of the push-pull signal with respect to a disk group included in the disc type determined by the first determination. The second determination is performed based on the value, and the third determination is performed based on the magnitude of the signal output from the light amount detection unit for the disk group included in the disk type determined by the second determination. Do,
An optical disc device characterized by the above. In any one of Claims 1 thru | or 7,
The disc discrimination means performs disc discrimination by irradiating the disc with a laser beam having the shortest wavelength,
An optical disc device characterized by the above. In claim 8,
The disc discrimination means performs disc discrimination by irradiating the disc with blue-violet laser light.
An optical disc device characterized by the above. In any one of Claim 1 thru | or 9,
The disc discrimination means performs disc discrimination by irradiating the disc with laser light of a predetermined wavelength while rotating the disc.
An optical disc device characterized by the above. In any of claims 1 to 10,
The disc discriminating means discriminates the disc based on the push-pull signal when the laser beam is moved in the radial direction with respect to the disc;
An optical disc device characterized by the above. Focusing the laser beam of a predetermined wavelength on the disc, discriminating the disc type based on the amplitude value of the radial push-pull signal detected at this time,
Disc discriminating method characterized by the above. Focusing the laser beam of a predetermined wavelength on the disc, discriminating the disc type based on the period and amplitude value of the radial push-pull signal detected at this time,
Disc discriminating method characterized by the above. Focusing the laser beam of a predetermined wavelength on the disc, discriminating the disc type based on the magnitude of the signal according to the amount of return light from the disc detected at this time and the amplitude value of the radial push-pull signal,
Disc discriminating method characterized by the above. Focusing the laser beam of a predetermined wavelength on the disc, discriminating the disc type based on the magnitude of the signal corresponding to the amount of return light from the disc detected at this time, the period and the amplitude value of the radial push-pull signal,
Disc discriminating method characterized by the above. In any one of claims 12 to 15,
An optical disc discriminating method characterized in that disc discrimination is performed by irradiating a disc with laser light having the shortest wavelength among laser beams that can be applied to the disc. In claim 16,
A disc discriminating method comprising discriminating discs by irradiating a disc with blue-violet laser light. In any of claims 12 to 17,
A disc discrimination method comprising disc discriminating by irradiating a disc with a laser beam having a predetermined wavelength while rotating the disc. In any one of claims 12 to 18,
A disc discrimination method characterized in that disc discrimination is performed based on the push-pull signal when a laser beam is moved in a radial direction with respect to a disc.

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