JP4797957B2 - Optical disc playback apparatus, media type discrimination method and program for optical disc playback apparatus - Google Patents

Description

The present invention relates to an optical disk reproducing apparatus, and a media type discriminating method and program of the optical disc reproducing apparatus.

  Conventional optical disks include CD (Compact Disc) and DVD (Digital Versatile Disc). Since CDs and DVDs have different specifications such as the wavelength of the laser beam to be used, the numerical aperture, and the track pitch of the optical disk, the optical disk reproducing apparatus must determine the type of these optical disks.

  As such an optical disk reproducing apparatus, there is an apparatus that discriminates a media type by performing an up search and a down search using a DVD laser for DVD (see, for example, Patent Document 1).

  Currently, BD (Blu-ray Disc), which is a next-generation DVD, has been developed. In this BD, there are plans to form up to eight BD layers as recording layers in the future, and in addition to this BD layer, there are DVD layers that are DVD specification recording layers and CD specification recording layers. Hybrid discs with a certain CD layer are also being studied.

  In such a (BD) hybrid disc, the lead-in information is recorded on the BD layer, and when the data of the DVD layer and the CD layer other than the BD layer is preferentially reproduced, the lead-in information is always present at present. Information must be read.

The optical disk reproducing apparatus reads this lead-in information, determines the media type and the number of layers of the optical disk, and performs spherical aberration correction (adjustment using BeamExpander or a liquid crystal element) for each layer.
Japanese Patent Laying-Open No. 2004-39094 (page 6-8, FIG. 5)

  However, in order to discriminate all media types of BD, DVD, CD, and hybrid disc, a focus search must be performed using laser light for each media. For this reason, it takes time to determine the media.

  Further, when reproducing a hybrid disc, even if the DVD layer and CD layer are preferentially reproduced, it is necessary to read the lead-in information of the BD layer.

  Furthermore, when the optical disc is a multilayered BD, the spherical aberration cannot be corrected for each layer unless the number of layers is determined after reading the lead-in information of the BD layer. For this reason, it takes time to reproduce.

The present invention has been made in view of such conventional problems, a short time the optical disk reproducing apparatus capable of determining the media type of the optical disk, providing media type determining method and program of the optical disk reproducing apparatus For the purpose.

Further, the present invention is a short time reproduction data optical disk reproducing apparatus, and an object thereof is to provide a media type discriminating method and program of the optical disc reproducing apparatus.

In order to achieve this object, an optical disc playback apparatus according to the first aspect of the present invention provides:
Based on the wavelength of irradiation Isa laser light, sequentially, the first recording layer to different depths, the second recording layer, the optical disc reproducing apparatus for reproducing at least one of which is formed an optical disk of the third recording layer,
A light emitting source for emitting the laser light;
An objective lens that focuses the laser light emitted from the light source on a focal point;
A search start position for searching the first recording layer is set between the first recording layer position and the second recording layer position on the optical disc, and the focal point of the objective lens is set to the first position from the set search start position. A first search for performing a first search for searching for the first recording layer by controlling the position of the objective lens so as to move to a preset first driving limit across the position of one recording layer And
The position of the objective lens is controlled so that the focal point moves from the first drive limit to a preset second drive limit beyond the third recording layer position, and the first recording layer A second search unit for performing a second search for searching the third recording layer,
When the first search unit performs the first search, the laser beam obtains a reflected signal by reflected light reflected by the first recording layer, and the second search unit acquires the second search signal. A reflected signal acquisition unit that acquires a reflected signal of reflected light reflected by the first recording layer to the third recording layer when the laser beam is searched;
The number of reflected signals acquired by the reflected signal acquisition unit when the first search unit performs the first search is the first signal number, and the second search unit performs the second search. When the number of reflected signals acquired by the reflected signal acquisition unit is a second signal number, the optical disc is based on the difference between the first signal number and the second signal number . And a media type determining unit that determines whether or not the recording layer has at least one of the recording layer and the third recording layer .

The media type determination unit may determine that the optical disk is not present when the first signal number is zero and the second signal number is also zero.

The first recording layer, the second recording layer, and the third recording layer respectively track the laser light emitted by the laser having the first wavelength, the laser having the second wavelength, and the laser having the third wavelength. It has a track that can be tracked,
Using the laser having the second wavelength as the light source, the position of the objective lens is controlled so that the focal point of the objective lens moves from the second driving limit toward the first driving limit. A third search unit for performing a third search for searching the third recording layer and the second recording layer;
After performing the second search, when the third search unit performs the third search, the first recording layer of the third recording layer or the second recording layer is detected, A tracking control unit that performs tracking so that the laser beam follows the track on which the data of the optical disc is recorded, using the laser of the second wavelength as the light source;
The media type determination unit
When the number of the first signals is zero and the number of the second signals is 1 or more, the tracking control unit performs tracking, and the laser beam of the second wavelength follows the track and is tracking on. When the media type of the optical disc is determined to be a media type having only the second recording layer and tracking is not turned on, the media type of the optical disc is a media type having only the third recording layer. You may make it discriminate | determine.

The media type determination unit
When the number of the first signals acquired by the reflected signal acquisition unit is 1 or more, a difference between the number of the first signals and the number of the second signals is obtained, and when the obtained difference is zero, the optical disc It may be determined that the media type is a media type having only the first recording layer.

The media type determination unit
When the number of the first signals acquired by the reflected signal acquisition unit is 1 or more, the difference between the number of the first signals and the number of the second signals is obtained. When the obtained difference is 1, the optical disc The media type may be a media type having the first recording layer and the second recording layer, or a media type having the first recording layer and the third recording layer.

The first recording layer, the second recording layer, and the third recording layer respectively track the laser light emitted by the laser having the first wavelength, the laser having the second wavelength, and the laser having the third wavelength. It has a track that can be tracked,
Using the laser having the second wavelength as the light source, the position of the objective lens is controlled so that the focal point of the objective lens moves from the second driving limit toward the first driving limit. A third search unit for performing a third search for searching the third recording layer and the second recording layer;
After performing the second search, when the third search unit performs the third search, the first recording layer of the third recording layer or the second recording layer is detected, A tracking control unit that performs tracking so that the laser beam follows the track on which the data of the optical disc is recorded, using the laser of the second wavelength as the light source;
The media type determination unit
When the first signal number is 1 or more and the difference between the first signal number and the second signal number is 1, when the tracking control unit performs tracking, the second signal is added to the track. When the laser light of the wavelength of the tracking follows and tracking on, it is determined that the media type of the optical disc is the media type having the first recording layer and the second recording layer, and when tracking on is not performed, You may make it discriminate | determine that the media type of the said optical disk is a media type which has the said 1st recording layer and the said 3rd recording layer.

The media type determination unit
When the number of the first signals acquired by the reflected signal acquisition unit is 1 or more, the difference between the number of the first signals and the number of the second signals is obtained, and when the obtained difference is 2, the optical disc A media type having the first recording layer and a plurality of the second recording layers, or a media type having the first recording layer, the single second recording layer, and the third recording layer. You may make it discriminate | determine that there exists.

The first recording layer, the second recording layer, and the third recording layer respectively track the laser light emitted by the laser having the first wavelength, the laser having the second wavelength, and the laser having the third wavelength. It has a track that can be tracked,
Using the laser having the second wavelength as the light source, the position of the objective lens is controlled so that the focal point of the objective lens moves from the second driving limit toward the first driving limit. A third search unit for performing a third search for searching the third recording layer and the second recording layer;
After performing the second search, when the third search unit performs the third search, the first recording layer of the third recording layer or the second recording layer is detected, A tracking control unit that performs tracking so that the laser beam follows the track on which the data of the optical disc is recorded, using the laser of the second wavelength as the light source;
The media type determination unit
When the first signal number acquired by the reflected signal acquisition unit is 1 or more and the difference between the first signal number and the second signal number is 2, the tracking control unit performed tracking. Sometimes when the laser beam of the second wavelength follows the track and tracking is turned on, the media type of the optical disc is a media type having the first recording layer and the second recording layer of multiple layers. When the tracking is not turned on, it is determined that the media type of the optical disc is the media type having the first recording layer, the single second recording layer, and the third recording layer. It may be.

The media type determination unit
When the first signal number acquired by the reflected signal acquisition unit is 1 or more, the difference between the first signal number and the second signal number is obtained. When the obtained difference is 3, the optical disc The media type may be determined to be a media type having the first recording layer, the multilayer second recording layer, and the third recording layer.

The media type determining unit, on the basis of the first signal number or the second number of signals, the media type of the optical disc, multilayer or the first recording layer is a media type of the optical disk of a single layer It may be determined whether the optical disc is of the media type.

The method of discriminating the media type of the optical disc playback apparatus according to the second aspect of the present invention is:
Based on the wavelength of irradiation Isa laser light, sequentially, the first recording layer to different depths, the second recording layer, the media type discrimination of the optical disc reproducing apparatus for reproducing at least one of which is formed an optical disk of the third recording layer A method,
An objective lens for setting a search start position for searching the first recording layer between the first recording layer position and the second recording layer position on the optical disc, and condensing laser light from the set search start position. by focusing of controlling the position of the objective lens to move to the first drive limit set in advance across the first recording layer position, the first search of searching for the first recording layer Steps to perform,
From the first drive limit, to a second drive limit set in advance beyond the third recording layer located as the focal point moves, and it controls the position of the objective lens, the first recording layer Through a second search for searching the third recording layer;
When the first search is performed, a reflected signal from the reflected light reflected from the first recording layer is acquired by the laser beam, and when the second search is performed, the laser beam is the first laser beam. Obtaining a reflected signal by reflected light reflected from the recording layer to the third recording layer;
When the first search is performed, the number of reflected signals acquired when the second search is performed is defined as the first signal number and the second signal number, respectively. And determining whether the optical disc has at least one of the second recording layer and the third recording layer based on a difference from the number of signals of 2. .

The program according to the third aspect of the present invention is:
Based on the wavelength of irradiation Isa laser light, sequentially, the first recording layer to different depths, the second recording layer, the third recording layer of at least one computer with the optical disc reproducing apparatus for reproducing the formed optical disc ,
A search start position for searching the first recording layer is set between the first recording layer position and the second recording layer position on the optical disc, and the focus of the objective lens of the optical pickup is determined from the set search start position. A procedure for performing a first search for searching the first recording layer by controlling the position of the objective lens so as to move to the first driving limit set in advance across the position of the first recording layer;
The position of the objective lens is controlled so that the focal point moves from the first drive limit to a preset second drive limit beyond the third recording layer position, and the first recording layer To a second search for searching the third recording layer;
When the first search is performed, the laser beam of the optical pickup obtains a reflected signal from the reflected light reflected by the first recording layer, and when the second search is performed, the laser beam is A procedure for obtaining a reflected signal by reflected light reflected by the first recording layer to the third recording layer;
When the first search is performed, the number of reflected signals acquired when the second search is performed is defined as the first signal number and the second signal number, respectively. A procedure for determining whether the optical disc has at least one of the second recording layer and the third recording layer based on a difference from the number of signals of 2;
Is to execute.

  According to the present invention, the media type can be determined in a short time. In addition, data can be reproduced in a short time.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical disc media type discriminating apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In the present embodiment, an optical disc media type discriminating device will be described as an optical disc reproducing device.

FIG. 1 shows the configuration of an optical disc reproducing apparatus according to this embodiment.
The optical disk reproducing apparatus according to the present embodiment includes a spindle motor 11, a driver 12, an optical pickup 13, a power supply 14, a switch 15, an RF amplifier 16, a signal processing unit 17, a servo circuit 18, and a RAM 19. ROM 20 and CPU 21.

  This optical disc playback apparatus discriminates the media type of the optical disc 1 in a short time and plays back recorded information. The optical disc 1 includes media types such as CD, DVD, BD, and hybrid disc. In these media type optical discs, at least one of a BD layer, a DVD layer, and a CD layer is formed as a recording layer on which data is recorded at different depths based on the wavelength of the irradiated laser beam.

  DVD media types include DVD_SL and DVD_DL. DVD_SL is a medium with one recording layer on which data is recorded, and DVD_DL is a medium with two recording layers.

  The hybrid disc is a disc having at least one recording layer of a CD layer as a CD recording layer and a DVD layer as a DVD recording layer together with a BD layer as a BD recording layer.

  For such a hybrid disc, media types such as BD / DVD_SL, BD / DVD_DL, BD / CD, BD / DVD_SL / CD, and BD / DVD_DL / CD are conceivable. Further, although a BD layer having a multilayer structure of 1 to 8 layers has been proposed, in this embodiment, the BD layer is referred to as a BD layer regardless of whether it is a single layer or a multiple layer.

  Note that BD / DVD_SL indicates that the BD layer and DVD_SL are stacked from the side irradiated with the laser beam. The same applies to hybrid media of other media types.

  The optical disc playback apparatus according to the present embodiment discriminates which of the media types of these optical discs is the disc to be discriminated.

  The diameters of CD, DVD, BD, and hybrid disc are all 12 cm, and the substrate thickness of the optical disc 1 is 1.2 mm. FIG. 2 shows the specifications of CD, DVD, and BD. The BD layer, DVD layer, and CD layer of the hybrid disc are formed according to these specifications. Note that a DVD has a plurality of specifications, and the wavelength λ and the numerical aperture NA are slightly different for each specification.

The wavelength λ of the laser beam for reading data becomes shorter in the order of CD, DVD, and BD. The track pitch becomes smaller as the wavelength λ of the laser light becomes shorter.

  The numerical aperture NA of the objective lens that focuses the laser beam on the recording layer of the optical disc 1 is a parameter that determines the resolution. The resolution is represented by 0.61 × (λ / NA). The higher the resolution (the smaller the beam spot diameter of the laser light), the higher the recording density.

  As can be seen from the equation representing the resolution, in order to increase the resolution, it is necessary to use an objective lens having a larger numerical aperture NA as the wavelength λ of the laser light becomes shorter.

  Further, as the numerical aperture is increased, the focal length is shortened, and the formed recording layer is shallow.

  FIG. 3A shows a cross section of the CD. The CD is formed by sequentially stacking a protective film 101c, a CD layer 102c, and a protective layer 103c. Laser light is irradiated from the protective layer 103c side.

  FIG. 3B shows a cross section of the DVD. A DVD is formed by sequentially stacking a dummy layer 101d, a DVD layer 102d, and a protective layer 103d. Since a DVD is formed by bonding two discs having a thickness of 0.6 mm, the DVD layer 102d is positioned approximately in the middle of the optical disc 1 in the thickness direction. Laser light is irradiated from the protective layer 103d side.

  FIG.3 (c) shows the cross section of BD. The BD is formed by sequentially stacking a substrate 101b, a BD layer 102b, and a protective layer 103b. Laser light is irradiated from the protective layer 103b side. In the case of BD, since an objective lens having a large numerical aperture is used, the BD layer 102b is formed most shallowly among CD, DVD, and BD when viewed from the laser beam irradiation side.

  FIG. 3D shows a cross section of the hybrid disk. The BD layer 102b, the DVD layer 102d, and the CD layer 102c of the hybrid disc are formed so that their depths correspond to the recording layers of BD, DVD, and CD, respectively.

  The optical disk reproducing apparatus according to the present embodiment determines the media type of the optical disk 1 in a short time using the difference in the depth and track pitch of each recording layer.

  In the case of a hybrid disc, lead-in information for determining the media type and the number of layers of the optical disc 1 is recorded on the inner circumference of the BD layer 102b.

  Returning to FIG. 1, the spindle motor 11 is a motor that rotates the optical disk 1, and the driver 12 rotates the spindle motor 11. The driver 12 is supplied with a signal from the CPU 21, and based on this signal, the spindle motor 11 is rotationally driven by a CAV (Constant Angular Velocity) method or a CLV (Constant Linear Velocity) method.

  The optical pickup 13 takes out data recorded on the recording layer 102 of the optical disc 1 by irradiating the optical disc 1 with laser light and converting the reflected light into an electric signal.

  As shown in FIG. 4, the optical pickup 13 includes a CD laser 41c, a DVD laser 41d, a BD laser 41b, a collimator lens 42, a beam shaping prism 43, a polarization beam splitter 44, a lens 45, and a light receiving element. 46, 1/4 wavelength plate 47, objective lenses 48 and 49, actuator 50, expander lens 51, actuator 52, polarization beam splitter 53, lenses 54 and 55, and light receiving elements 56 and 57. .

  The CD laser 41c, the DVD laser 41d, and the BD laser 41b are emission sources that emit laser light, and emit laser beams having wavelengths of 780 nm, 650 nm, and 405 nm, respectively. Laser diodes are used for the CD laser 41c, DVD laser 41d, and BD laser 41b.

  The CD laser 41c, DVD laser 41d, and BD laser 41b are used when reading data from the CD layer 102c, DVD layer 102d, and BD layer 102b, respectively. These CD laser 41c, DVD laser 41d, and BD laser 41b emit linearly polarized laser light.

  The collimator lens 42 is a lens that collimates the laser light emitted from the CD laser 41c, the DVD laser 41d, and the BD laser 41b.

  The beam shaping prism 43 is a prism that performs radiation angle distribution correction on the light collimated by the collimator lens 42 and shapes the light from an elliptical beam into a substantially circular beam.

  The polarization beam splitter 44 reflects part of the laser light emitted from the CD laser 41c, DVD laser 41d, and BD laser 41b, guides the reflected light to the light receiving element 46 side, and transmits the other laser light. The light transmitted through the quarter-wave plate 47 is reflected toward the polarization beam splitter 53 side.

  The light receiving element 46 is used for automatic output control of the CD laser 41c, the DVD laser 41d, and the BD laser 41b, and receives the reflected light reflected by the polarization beam splitter 44 and condensed by the lens 45.

  The quarter wavelength plate 47 is for converting linearly polarized light transmitted through the polarizing beam splitter 44 into circularly polarized light.

  The objective lenses 48 and 49 are lenses for condensing the laser light emitted from the CD laser 41c, the DVD laser 41d, and the BD laser 41b at a focal point. As shown in FIG. 5, the positions of the objective lenses 48 and 49 with respect to the disk surface of the optical disk 1 include ranges in which the focal points are respectively matched with the CD layer 102c, the DVD layer 102d, and the BD layer 102b of the optical disk 1. A drive upper limit Pmax and a drive lower limit Pmin are set in advance.

  The drive upper limit Pmax is set so that the objective lenses 48 and 49 are closest to the optical disc 1, and the focal points of the objective lenses 48 and 49 are deeper than the CD layer 102c (on the protective film 101c side in the case of CD). The That is, the drive upper limit Pmax is set in advance so that the focal points of the objective lenses 48 and 49 move from the drive lower limit Pmin beyond the CD layer 102c during search.

  The drive lower limit Pmin is a position where the objective lenses 48 and 49 are farthest from the optical disc 1, and is set so that the focal points of the objective lenses 48 and 49 are shallower than the BD layer 102b (on the protective layer 103b side in the case of BD). The

  That is, the drive lower limit Pmin is set in advance so that the focal points of the objective lenses 48 and 49 move across the BD layer 102b from the focus search start position Pstart during the search. The position (distance) in the optical axis direction of the laser light of the objective lenses 48 and 49 with respect to the disk 1 varies within the range between the drive upper limit Pmax and the drive lower limit Pmin.

  The actuator 50 is controlled by the CPU 21 and controls the positions of the objective lenses 48 and 49.

  The expander lens 51 is an extractor that corrects spherical aberration so that the spherical aberration caused by the difference in thickness of the CD protective layer 103c, DVD protective layer 103d, and BD protective layer 103b and the optical disc 1 is corrected. This is a lens for performing panda adjustment, and includes a convex lens 51a and a concave lens 51b.

  The spherical aberration is canceled by adding an optical path difference to the laser beam from the CD laser 41c, DVD laser 41d, and BD laser 41b.

  The convex lens 51a and the concave lens 51b are inserted in the optical path between the CD laser 41c, the DVD laser 41d, and the BD laser 41b and the optical disc 1, and the concave lens 51b is disposed on the CD laser 41c, DVD laser 41d, and BD laser 41b side. Is done. An annular step for adding an optical path difference is formed on the surface of the concave lens 51b on the CD laser 41c, DVD laser 41d, and BD laser 41b side.

  The convex lens 51a and the concave lens 51b are supported by a lens tube (not shown). The convex lens 51a is fixed to the lens cylinder, and the concave lens 51b is supported by the lens cylinder so as to be movable in the optical axis direction.

  The expander lens 51 is configured such that the distance between the convex lens 51a and the concave lens 51b is variable. The spherical aberration is different for each layer, and the optical path difference can be adjusted by setting the interval corresponding to each layer.

  The actuator 52 is for controlling the distance between the convex lens 51 a and the concave lens 51 b of the expander lens 51 as expander adjustment, and is controlled by the CPU 21.

  The polarization beam splitter 53 is for splitting the light reflected by the polarization beam splitter 44 into two. The polarization beam splitter 53 reflects a part of the light reflected by the polarization beam splitter 44 to receive the light receiving element 56. To the light receiving element 57 through the other light.

  The light receiving element 56 is for detecting a focus error, and receives the light reflected by the polarization beam splitter 53 and condensed by the lens 54. The focus error is an error with respect to the focus distance when the laser beam is focused on the surface of the optical disc 1. For example, a knife edge method is used for detection of the focus error. The light receiving element 56 outputs a signal for generating an FE (focus error) signal indicating a focus error.

  The light receiving element 57 is for detecting an RF (Radio Frequency) signal and detecting a tracking error, and receives light transmitted through the polarization beam splitter 53 and condensed by the lens 55. The tracking error is an error in the position of a light spot formed on the surface of the optical disc 1 by irradiating a laser beam with respect to a normal track position of the optical disc 1. Note that the methods for detecting the tracking error of BD, DVD, and CD are different.

  The light receiving element 57 outputs a signal for generating a TE (tracking error signal) signal indicating a tracking error.

  Returning to FIG. 1, the power source 14 supplies current to each part including the optical pickup 13. The switch 15 is inserted between the power supply 14 and the optical pickup 13 and controlled by the CPU 21 to connect a current path between the power supply 14 and the CD laser 41c, DVD laser 41d, and BD laser 41b of the optical pickup 13. , To shut off.

  The RF amplifier 16 decodes the signals output from the light receiving elements 56 and 57 of the optical pickup 13 to generate an RF signal, an FE signal, and a TE signal. The RF amplifier 16 supplies the generated signals to the signal processing unit 17 and supplies the FE signal and the TE signal to the servo circuit 18.

  The signal processing unit 17 obtains a signal supplied from the RF amplifier 16 and decodes the RF signal to generate a reproduction signal indicating data recorded on the optical disc 1.

  The servo circuit 18 is controlled and turned on by the CPU 21, performs focus servo based on the FE signal supplied from the RF amplifier 16, and performs tracking servo based on the TE signal.

  The focus servo is a control for pulling in the focus so that each recording layer of the optical disc 1 is focused. When the servo circuit 18 is turned on, the servo circuit 18 sets a voltage so that the signal level of the FE signal supplied from the RF amplifier 16 becomes 0, and supplies the signal of this voltage to the actuator 50 of the optical pickup 13.

  The tracking servo is control for causing the light spot to follow the track of the optical disc 1. When the focus is pulled, the servo circuit 18 sets a voltage so that the voltage of the TE signal supplied from the RF amplifier 16 becomes 0, and this voltage signal is used as an actuator (for tracking servo provided in the optical pickup 13). (Not shown).

  The RAM 19 is a memory for storing data necessary for work by the CPU 21, and the ROM 20 is a memory for storing data of a program executed by the CPU 21. The ROM 20 stores data of media type determination processing, which will be described later, as a program.

The CPU 21 is a device that controls the entire optical disc playback apparatus.
Specifically, the CPU 21 turns off the servo circuit 18, supplies a rotation control signal to the driver 12, and rotates the optical disc 1 via the spindle motor 11. When the optical disk 1 rotates, the CPU 21 turns on the servo circuit 18.

  Then, the CPU 21 reads the program data of the media type determination process from the ROM 20 and executes the media type determination process.

  In order to determine the media type without reading the lead-in information of the BD layer 102b, the CPU 21 first sets a focus search start position Pstart for searching the BD layer 102b.

  As shown in FIG. 5, the CPU 21 sets the focus search start position Pstart between a position where the DVD layer 102d of the disc 1 to be discriminated is assumed to be present and a position where the BD layer 102b is assumed to be present. Then, the actuator 50 of the optical pickup 13 is controlled so that the objective lenses 48 and 49 are focused on the focus search start position Pstart (t1).

  When the CPU 21 sets the focus search start position Pstart in this way, the focal points of the objective lenses 48 and 49 move from the set focus search start position Pstart across the position where the BD layer 102b is assumed to exist. The positions of the objective lenses 48 and 49 are controlled. In this way, the CPU 21 performs a focus down search for searching the BD layer 102b (t2).

  The CPU 21 acquires a reflection signal based on the reflected light that the laser light reflects from the BD layer 102b by performing a focus down search.

  When the focal points of the objective lenses 48 and 49 are moved in the vicinity of the recording layer, the FE signal draws an S-curve by reflected light. The CPU 21 acquires the reflected signal from the RF amplifier 16 via the signal processing unit 17 using the FE signal having an S-shaped curve as a reflected signal.

  Since the CPU 21 acquires this reflected signal in a short time, only the DVD laser 41d is used for acquiring this reflected signal. If the laser wavelength and numerical aperture of the laser beam of the DVD laser 41d are used, a reflected signal can be obtained in any recording layer of the CD layer 102c, the DVD layer 102d, and the BD layer 102b.

  When using the DVD laser 41d, the CPU 21 controls the switch 15 so as to connect the power supply 14 and the DVD laser 41d.

  The CPU 21 stores the number n_dwn of reflected signals acquired from the signal processing unit 17 when the focus down search is performed in the RAM 19.

  When the focal positions of the objective lenses 48 and 49 reach the driving lower limit Pmin, the CPU 21 controls the positions of the objective lenses 48 and 49 so that the focal points of the objective lenses 48 and 49 move from the driving lower limit Pmin to the driving upper limit Pmax. .

  The CPU 21 controls the positions of the objective lenses 48 and 49 by controlling the actuator 50 of the optical pickup. In this way, the CPU 21 performs a focus-up search for searching for the BD layer 102b, the DVD layer 102d, and the CD layer 102c (t3).

  The CPU 21 acquires the reflection signal from the signal processing unit 17 when performing the focus-up search, and stores the acquired number n_up of the reflection signals in the RAM 19.

  The CPU 21 determines each recording layer of the optical disc 1 based on the number n_dwn and n_up of the reflected signals, and determines the media type of the optical disc 1.

  First, the CPU 21 determines the presence / absence of the BD layer 102b and the number of layers of the BD layer 102b based on the number n_dwn of reflected signals.

  When n_dwn = 0, this indicates that the BD layer 102b does not exist on the disc 1 to be discriminated.

  Further, when the number n_up of reflected signals is zero, no reflected signal is obtained at the time of focus down search or focus up search. This indicates that the optical disk 1 is not loaded. Therefore, if the CPU 21 determines that n_dwn = 0 and n_up = 0, it determines that the optical disk 1 is not loaded.

  When n_dwn = 0 and n_up ≧ 1, this indicates that the CD layer 102c or the DVD layer 102d exists and the media type of the optical disc 1 is CD or DVD.

  When determining that n_dwn = 0 and n_up ≧ 1, the CPU 21 performs a focus down search using the DVD laser 41d from the drive upper limit Pmax (t4), and obtains a reflected signal. Then, using the DVD laser 41d, the CPU 21 performs focus tracking on the recording layer from which the reflected signal is first obtained, and performs tracking.

  When the DVD laser 41d is used, tracking is turned on for the DVD layer 102d, but tracking is not turned on for the CD layer 102c due to a difference in track pitch.

  Therefore, the CPU 21 determines that the recording layer is the DVD layer 102d when tracking is turned on, and that the recording layer is the CD layer 102c when tracking is not turned on.

  When determining that the recording layer is the DVD layer 102d, the CPU 21 determines whether the optical disc 1 is DVD_SL or DVD_DL based on the number n_up of reflected signals.

  Next, when n_dwn ≧ 1, this indicates that the BD layer 102b exists. When determining that n_dwn ≧ 1, the CPU 21 reads the number n_up of reflected signals from the RAM 19 and obtains the difference (n_up−n_dwn) between the number n_up and the number n_dwn of reflected signals. This difference (n_up−n_dwn) indicates the number of DVD layers 102d or CD layers 102c existing in addition to the BD layer 102b.

  When n_up−n_dwn = 0, this indicates that there is no recording layer other than the BD layer 102b. When determining that n_up−n_dwn = 0, the CPU 21 determines that the optical disc 1 is a BD.

  In this case, when the number n_dwn or n_up of the reflected signals is 1, the CPU 21 determines that the optical disc 1 is BD_SL, and when the number n_dwn of the reflected signals is 2, the optical disc 1 is BD_DL.

  Further, the number of BD layers can be determined from the number n_dwn of the obtained reflected signals. In the present embodiment, the number of BD layers is determined in the recording layer discrimination by comparison with the number n_dwn of the subsequent reflected signals. Regardless of the case, n_dwn = 1 when there is a BD layer, and n_dwn = 0 when there is no BD layer.

  When n_up−n_dwn ≧ 1, this indicates that there is a recording layer in addition to the BD layer 102b, and when n_up−n_dwn = 1, this indicates that there is one recording layer other than the BD layer 102b. Indicates that

  When determining that n_up−n_dwn = 1, the CPU 21 determines whether the recording layer is the DVD layer 102d or the CD layer 102c. For this reason, the CPU 21 performs a focus down search using the DVD laser 41d from the drive upper limit Pmax (t4), and acquires a reflection signal.

  Then, using the DVD laser 41d, the CPU 21 performs focus tracking on the recording layer from which the reflected signal is first obtained, and performs tracking. When the tracking is turned on, the CPU 21 determines that the recording layer is the DVD layer 102d and the media type of the optical disc 1 is BD / DVD_SL. When the tracking is not turned on, the CPU 21 determines that the recording layer is the CD layer 102c and the media type of the optical disc 1 is BD / CD.

  When n_up−n_dwn = 2, this indicates that the CPU 21 has two recording layers in addition to the BD layer 102b. When determining that n_up−n_dwn = 2, the CPU 21 determines whether the recording layer is the DVD layer 102d or the CD layer 102c. For this reason, the CPU 21 performs a focus down search using the DVD laser 41d from the drive upper limit Pmax, and acquires a reflected signal.

  Then, using the DVD laser 41d, the CPU 21 performs focus tracking on the recording layer from which the reflected signal is first obtained, and performs tracking. When the tracking is turned on, the CPU 21 determines that the recording layer is the DVD layer 102d and the media type of the optical disc 1 is BD / DVD_DL. When tracking is not turned on, the CPU 21 determines that the recording layer is the CD layer 102c and the media type of the optical disc 1 is BD / DVD_SL / CD.

  Next, when n_up−n_dwn = 3, this indicates that there are three recording layers in addition to the BD layer 102b. When determining that n_up−n_dwn = 3, the CPU 21 determines that the optical disc 1 is a BD / DVD_DL / CD.

  When the CPU 21 discriminates the media type of the optical disc 1 in this way and is instructed to reproduce data from each recording layer, the CPU 21 adjusts the focal positions of the objective lenses 48 and 49 to the designated recording layer.

  Then, the CPU 21 controls the optical pickup 13 so as to read the data recorded on the recording layer. Then, the CPU 21 acquires a reproduction signal from the signal processing unit 17 and outputs the acquired reproduction signal.

Next, the operation of the optical disc playback apparatus according to this embodiment will be described.
The CPU 21 turns off the servo circuit 18 and supplies a rotation control signal to the driver 12, and turns on the servo circuit 18 when the optical disk 1 rotates.

  Then, the CPU 21 reads program data for media type determination processing from the ROM 20. And CPU21 performs media type discrimination | determination processing according to the flowchart shown to FIGS.

  The CPU 21 sets the focus search start position Pstart between the DVD layer 102d and the BD layer 102b (step S11).

  The CPU 21 performs a focus down search using the DVD laser 41d (step S12).

  The CPU 21 acquires the reflected signal when the focus down search is performed from the RF amplifier 16, and stores the number n_dwn in the RAM 19 (step S13).

  The CPU 21 determines whether or not the number n_dwn of reflected signals is 1 or more (step S14).

  When it is determined that the number n_dwn of reflected signals is less than 1 (step S14; No), the CPU 21 performs a focus-up search from the drive lower limit Pmin to the drive upper limit Pmax using the DVD laser 41d (step S15).

  The CPU 21 acquires the reflection signal when the focus-up search is performed, and stores the number n_up in the RAM 19 (step S16).

  The CPU 21 determines whether or not the number n_up of the acquired reflection signals is 1 or more (step S17).

  When it is determined that the number n_up of the acquired reflection signals is 1 or more (step S17; Yes), the CPU 21 performs a focus down search from the drive upper limit Pmax using the DVD laser 41d (step S18).

  When acquiring the reflected signal from the signal processing unit 17, the CPU 21 uses the DVD laser 41d to focus on the recording layer from which the first obtained reflected signal is obtained (step S19).

The CPU 21 performs tracking on the recording layer using the DVD laser 41d (step S20).
The CPU 21 determines whether tracking is turned on (step S21).

  If it is determined that the tracking has been turned on (step S21; Yes), the CPU 21 determines that the media type of the optical disc 1 is DVD (step S22). If it discriminate | determines in this way, CPU21 will complete | finish this media type discrimination | determination process.

  On the other hand, if it is determined that the tracking is not turned on (step S21; No), the CPU 21 determines that the media type of the optical disc 1 is CD (step S23). If it discriminate | determines in this way, CPU21 will complete | finish this media type discrimination | determination process.

  When it is determined that the number n_dwn of reflected signals is 1 or more (step S14; Yes), the CPU 21 performs a focus-up search using the DVD laser 41d (step S25).

  The CPU 21 acquires the reflection signal when the focus-up search is performed, and stores the number n_up in the RAM 19 (step S26).

  CPU21 calculates | requires the difference (n_up-n_dwn) of the number n_up of reflected signals, and n_dwn, and determines whether the difference (n_up-n_dwn) is one or more (step S27).

  When it is determined that the difference (n_up−n_dwn) is less than 1 (step S27; No), the CPU 21 determines that the media type of the optical disc 1 is BD (step S28). The CPU 21 determines whether the BD layer 102b of the optical disc 1 is one layer or two layers based on the number n_up or n_dwn of reflected signals. If it is determined that the media type of the optical disc 1 is BD, the CPU 21 ends the media type determination process.

  When the difference (n_up−n_dwn) is determined to be 1 or more (step S27; Yes), the CPU 21 determines whether or not the difference (n_up−n_dwn) is 1 (step S29).

  When it is determined that the difference (n_up−n_dwn) is 1 (step S29; Yes), the CPU 21 performs a focus down search from the drive upper limit Pmax using the DVD laser 41d (step S30).

  When the reflected signal is obtained, the CPU 21 focuses on the recording layer from which the reflected signal is first obtained (step S31).

The CPU 21 performs tracking on this recording layer using the DVD laser 41d (step S32).
The CPU 21 determines whether tracking is turned on (step S33).

  If it is determined that the tracking has been turned on (step S33; Yes), the CPU 21 determines that the media type of the optical disc 1 is BD / DVD_SL (step S34). If it discriminate | determines in this way, CPU21 will complete | finish this media type discrimination | determination process.

  On the other hand, when it is determined that the tracking is not turned on (step S33; No), the CPU 21 determines that the media type of the optical disc 1 is BD / CD (step S35). If it discriminate | determines in this way, CPU21 will complete | finish this media type discrimination | determination process.

  When it is determined that the difference (n_up−n_dwn) is not 1 (step S29; No), the CPU 21 determines whether or not the difference (n_up−n_dwn) between the number of reflected signals n_up and n_dwn is 2 (step S29; No). Step S36).

  When it is determined that the difference (n_up−n_dwn) is 2 (step S36; Yes), the CPU 21 performs a focus down search from the drive upper limit Pmax using the DVD laser 41d (step S37).

  When the reflected signal is obtained, the CPU 21 focuses on the recording layer from which the reflected signal is first obtained (step S38).

The CPU 21 performs tracking on the recording layer using the DVD laser 41d (step S39).
The CPU 21 determines whether tracking is turned on (step S40).

  If it is determined that the tracking has been turned on (step S40; Yes), the CPU 21 determines that the media type of the optical disc 1 is BD / DVD_DL (step S41). If it discriminate | determines in this way, CPU21 will complete | finish this media type discrimination | determination process.

  On the other hand, when it is determined that tracking is not turned on (step S40; No), the CPU 21 determines that the media type of the optical disc 1 is BD / DVD_SL / CD (step S42). If it discriminate | determines in this way, CPU21 will complete | finish this media type discrimination | determination process.

  If it is determined that the difference is not 2 (step S36; No), the CPU 21 determines that the media type of the optical disc 1 is BD / DVD_DL / CD (step S43). If it discriminate | determines in this way, CPU21 will complete | finish this media type discrimination | determination process.

Next, the media type discrimination process of this optical disc playback apparatus will be specifically described.
As shown in FIGS. 10 to 15, the CPU sets the focus search start position Pstart between the BD layer 102b and the DVD layer 102d (processing in step S11).

  The CPU 21 performs a focus down search from the focus search start position Pstart using the DVD laser 41d (processing in step S12).

  As shown in FIGS. 10A, 10B, 11A, and 11B, when the optical disc 1 does not have the BD layer 102b or when the optical disc 1 is not loaded, the CPU 21 performs focus down. When the search is performed, the number n_dwn of reflection signals to be acquired becomes zero (step S14; No).

  In this case, the CPU 21 performs a focus-up search (step S15).

  When the focus-up search is performed, as shown in FIG. 10A, if the optical disc 1 is DVD_SL, the number of reflected signals n_up obtained is 1, and the optical disc 1 is shown in FIG. 10B. If the media type is DVD_DL, the number of reflected signals n_up obtained is 2. Further, as shown in FIG. 11A, when the media type of the optical disc 1 is CD, the number n_up of reflected signals obtained is 1.

  In this case, since n_up ≧ 1 (step S17; Yes), the CPU 21 performs a focus down search (step S18). As shown in FIGS. 10A and 10B, when the media type of the optical disc 1 is DVD_SL or DVD_DL, the layer from which the reflected signal is first obtained is the DVD layer 102d.

  For this reason, the CPU 21 focuses on the DVD layer 102d (step S19), and performs tracking using the DVD laser 41d on the DVD layer 102d (step S20).

  If tracking is performed, the tracking is turned on (step S21; Yes), so the CPU 21 determines that the media type of the optical disc 1 is DVD (step S22).

  If the number of reflected signals n_up = 1, the CPU 21 determines that the media type of the optical disc 1 is DVD_SL. If n_up = 2, the CPU 21 determines that the media type of the optical disc 1 is DVD_DL.

  As shown in FIG. 11A, when the media type of the optical disc 1 is CD, when the CPU 21 performs a focus down search (step S18), the layer from which the reflected signal is first obtained is the CD layer 102c. is there.

  For this reason, the CPU 21 focuses on the CD layer 102c (step S19) and performs tracking using the DVD laser 41d (step S20).

  When the media type of the optical disc 1 is CD, tracking is not turned on even if tracking is performed using the DVD laser 41d (step S21; No). For this reason, the CPU 21 determines that the media type of the optical disc 1 is CD (processing in step S23).

  When the optical disk 1 is not loaded, as shown in FIG. 11B, when the CPU 21 performs a focus-up search (step S15), the number of reflected signals n_up obtained is zero ( Step S17; No).

  In this case, the CPU 21 determines that the optical disk 1 is not loaded (step S24).

  Next, as shown in FIGS. 12 to 15, when the optical disc 1 has the BD layer 102b, when the CPU 21 performs a focus down search from the focus search start position Pstart using the DVD laser 41d (in step S12). Process), the number n_dwn of reflected signals obtained is 1 (step S14; Yes).

  For this reason, the CPU 21 performs a focus-up search using the DVD laser 41d (step S25).

  As shown in FIGS. 12A and 12B, when the optical disc 1 is a BD, the number n_up of reflected signals obtained (processing in step S25) and the number n_dwn of reflected signals obtained (processing in step S12) are as follows. And the difference (n_up−n_dwn) becomes zero (step S27; No).

  For this reason, the CPU 21 determines that the media type of the optical disc 1 is BD (step S28). Then, as shown in FIG. 12A, when the media type of the optical disc 1 is BD_SL, the number n_dwn of reflected signals is 1, and the CPU 21 determines that the media type of the optical disc 1 is BD_SL.

  As shown in FIG. 12B, when the media type of the optical disc 1 is BD_DL, the number n_dwn of reflected signals is 2, and the CPU 21 determines that the media type of the optical disc 1 is BD_DL.

  As shown in FIGS. 13 to 15, when the optical disk 1 is a hybrid disk, the difference (n_up−n_dwn) between the number n_up of reflected signals (process in step S25) and the number n_dwn of reflected signals (process in step S12). ) Is 1 or more (step S27; Yes).

  As shown in FIG. 13A, when the media type of the optical disk 1 is BD / DVD_SL, as shown in FIG. 13B, when the media type of the optical disk 1 is BD / CD, the difference (n_up−n_dwn) Becomes 1 (step S29; Yes).

  For this reason, the CPU 21 performs a focus down search using the DVD laser 41d (step S30). As shown in FIG. 13A, when the media type of the optical disc 1 is BD / DVD_SL, the first layer from which the reflected signal is obtained is the DVD layer 102d.

  For this reason, the CPU 21 focuses on the DVD layer 102d (step S31), and performs tracking using the DVD laser 41d (step S32).

  When tracking is performed, the tracking is turned on (step S33; Yes), so the CPU 21 determines that the media type of the optical disc 1 is BD / DVD_SL (processing of step S34).

  As shown in FIG. 13B, when the media type of the optical disc 1 is BD / CD, the layer from which the reflected signal is first obtained is the CD layer 102c.

  For this reason, the CPU 21 focuses on the CD layer 102c (step S31), and performs tracking using the DVD laser 41d (step S32).

  In the case of the CD layer 102c, even if tracking is performed using the DVD laser 41d, tracking is not turned on (step S33; No). For this reason, the CPU 21 determines that the media type of the optical disc 1 is BD / CD (step S35).

  When the media type of the optical disc 1 is BD / DVD_DL as shown in FIG. 14A, when the media type of the optical disc 1 is BD / DVD_SL / CD as shown in FIG. 14B, the difference (n_up−n_dwn) ) Becomes 2 (step S36; Yes).

  For this reason, the CPU 21 performs a focus down search using the DVD laser 41d (step S37). As shown in FIG. 14A, when the media type of the optical disc 1 is BD / DVD_DL, the recording layer from which the reflected signal is first obtained is the DVD layer 102d.

  For this reason, the CPU 21 focuses on the DVD layer 102d (step S38), and performs tracking using the DVD laser 41d (step S39).

  If tracking is performed, the tracking is turned on (step S40; Yes), so the CPU 21 determines that the media type of the optical disc 1 is BD / DVD_DL (processing of step S41).

  As shown in FIG. 14A, when the media type of the optical disc 1 is BD / DVD_SL / CD, the first layer from which the reflected signal is obtained is the CD layer 102c.

  Therefore, the CPU 21 focuses on the CD layer 102c (step S38) and performs tracking using the DVD laser 41d (step S39).

  In the case of the CD layer 102c, even if tracking is performed using the DVD laser 41d, the tracking is not turned on (step S40; No). For this reason, the CPU 21 determines that the media type of the optical disc 1 is BD / DVD_SL / CD (processing in step S42).

  As shown in FIG. 15, when the media type of the optical disc 1 is BD / DVD_DL / CD, the difference (n_up−n_dwn) is 3 (step S36; No).

  In this case, the CPU 21 determines that the media type of the optical disc 1 is BD / DVD_DL / CD (step S43).

  For example, when an instruction is given to read data from the CD layer 102c of the optical disc 1 whose media type is BD / DVD_DL / CD, the CPU 21 focuses the objective lenses 48 and 49 on the CD layer 102c. .

  The CPU 21 controls the optical pickup 13 so as to read data from the CD layer 102 c and outputs the reproduction signal acquired from the signal processing unit 17.

  As described above, according to the present embodiment, the CPU 21 sets the focus down search start position Pstart between the DVD layer 102d and the BD layer 102b, and uses the DVD laser 41d to focus down search and focus up search. I do. Then, the CPU 21 discriminates the media type of the optical disc 1 based on the numbers n_dwn and n_up of the reflected signals.

  Therefore, the CD layer 102c, the DVD layer 102d, and the BD layer 102b can be discriminated only by using the DVD laser 41d, and by performing the focus up search only once and the focus down search at most twice. For this reason, the media type of the optical disc 1 can be determined in a short time.

  Further, since the media type of the optical disc 1 can be determined without reading the lead-in information of the BD layer 102b, the time required for the determination can be greatly reduced, and the time required for reproduction can also be reduced. Can do.

  In particular, when the DVD layer 102d and the CD layer 102c are preferentially reproduced during the reproduction of the hybrid disc, the reading process of the lead-in information of the BD layer 102b is unnecessary, which is effective.

  Further, when the optical disc 1 is a BD having a multi-layer structure, the number of layers can be determined without reading the lead-in information of the BD layer 102b. Therefore, the spherical aberration correction is performed in advance for each layer before reproducing the data of each recording layer. It is also possible to shorten the time until data reproduction.

  Further, when determining whether or not the disc is a hybrid disc, it can be determined only by the number of reflected signals when the focus down search and the focus up search are performed, so this determination can be easily made.

In carrying out the present invention, various forms are conceivable and the present invention is not limited to the above embodiment.
For example, in the above embodiment, when it is determined that the difference (n_up−n_dwn) between the number of reflected signals n_up and n_dwn is 2 (step S36; Yes), the CPU 21 determines whether the optical disc 1 is BD / DVD_SL / CD. The DVD laser 41d is used to determine whether it is BD / DVD_DL.

  However, the CPU 21 can also determine whether the media type of the optical disc 1 is BD / DVD_SL / CD or BD / DVD_DL using a CD laser instead of the DVD laser 41d.

  This is because the media other than the CD cannot be turned on using the CD laser 41c. Therefore, the focus search operation can be performed by either a focus up search or a focus down search.

  In this case, the CPU 21 executes media type determination processing according to the flowchart shown in FIG.

  That is, when it is determined that the difference (n_up−n_dwn) is 2 (step S36; Yes), the CPU 21 performs a focus down search from the drive upper limit Pmax using a CD laser (step S51).

  When the reflected signal is obtained, the CPU 21 focuses on the recording layer from which the reflected signal is first obtained (step S52).

The CPU 21 performs tracking on this recording layer using the CD laser 41c (step S53).
The CPU 21 determines whether tracking is turned on (step S54).

  If it is determined that the tracking is on (step S54; Yes), the CPU 21 determines that the media type of the optical disc 1 is BD / DVD_SL / CD (step S55).

  On the other hand, when it is determined that the tracking is not turned on (step S54; No), the CPU 21 determines that the media type of the optical disc 1 is BD / DVD_DL (step S56).

The operation of the media type discrimination process will be specifically described.
As shown in FIG. 17A, when the media type of the optical disc 1 is BD / DVD_SL / CD, when the CPU 21 performs a focus down search from the drive upper limit Pmax using a CD laser (processing in step S51), first. The recording layer from which the reflected signal is obtained is the CD layer 102c.

  For this reason, the CPU 21 focuses on the CD layer 102c (step S52) and performs tracking using the CD laser 41c (step S53).

  In the case of the CD layer 102c, when tracking is performed using the CD laser 41c, the tracking is turned on (step S54; Yes). For this reason, the CPU 21 determines that the media type of the optical disc 1 is BD / DVD_SL / CD (processing in step S55).

  On the other hand, when the media type of the optical disc 1 is BD / DVD_DL as shown in FIG. 17B, when the CPU 21 performs a focus down search from the drive upper limit Pmax using the CD laser (processing in step S51), the first reflection is performed. The recording layer from which a signal is obtained is the DVD layer 102d.

  In the case of the DVD layer 102d, since tracking is not performed when tracking is performed (step S54; No), the CPU 21 determines that the media type of the optical disc 1 is BD / DVD_DL (processing in step S56).

  Thus, although the laser used for discriminating the media type of the optical disc 1 is not single, the media type of the optical disc 1 can be discriminated using a CD laser instead of the DVD laser 41d.

  In the above embodiment, although the media type DVD_SL / CD and DVD_DL / CD are not specifically described, the number n_dwn and n_up of reflected signals and the presence / absence of tracking are also determined for the media type. It becomes possible to discriminate by discriminating.

  In the above embodiment, the CPU 21 sets the focus start position Pstart between the BD layer 102b and the DVD layer 102d on the disc to be discriminated, and performs the focus down search and the focus up search.

  However, the CPU 21 sets the focus start position Pstart between the DVD layer 102d and the CD layer 102c and performs a focus-up search and a focus-down search on the disc to be discriminated, and acquires a reflected signal. Thus, the media type of the optical disc can be determined.

  In the above-described embodiment, the program is described as being stored in advance in a memory or the like. However, a program for operating the optical disc playback apparatus as all or part of the apparatus or executing the above-described processing is stored in a flexible disk, a CD-ROM (Compact Disk Read-Only Memory), a DVD (Digital Versatile Disc). ), Stored on a computer-readable recording medium such as MO (Magneto Optical disc), etc., installed on another computer and operated as the above-mentioned means, or the above-mentioned steps may be executed. .

  Furthermore, the program may be stored in a disk device or the like included in a server device on the Internet, and may be downloaded onto a computer by being superimposed on a carrier wave, for example.

It is a block diagram which shows the structure of the optical disk reproducing | regenerating apparatus concerning embodiment of this invention. It is a figure which shows the specification of CD type | system | group, DVD type | system | group, and BD type | mold optical disk. FIG. 4 is a cross-sectional view of each optical disk, where (a) shows a cross section of a CD, (b) shows a cross section of a DVD, (c) shows a cross section of a BD, and (d) shows a cross section of the hybrid disk. Indicates. It is a figure which shows the structure of the optical pick-up shown in FIG. It is a figure which shows the process of CPU shown in FIG. It is a flowchart (1) which shows the media type discrimination | determination process (the 1) which CPU shown in FIG. 1 performs. It is a flowchart (2) which shows the media type discrimination | determination process (the 2) which CPU shown in FIG. 1 performs. It is a flowchart (3) which shows the media type discrimination | determination process (the 3) which CPU shown in FIG. 1 performs. It is a flowchart (4) which shows the media type discrimination | determination process (the 4) which CPU shown in FIG. 1 performs. It is a figure which shows the specific media type discrimination | determination process of an optical disk reproducing device, (a) shows the process when the media type of an optical disk is DVD_SL, (b) is the process when the media type of an optical disk is DVD_DL Indicates. It is a figure which shows the specific media type discrimination | determination process of an optical disk reproducing device, (a) shows the process when the media type of an optical disk is CD, (b) shows the process when the optical disk is not loaded. Show. It is a figure which shows the specific media type discrimination | determination process of an optical disk reproducing device, (a) shows the process when the media type of an optical disk is BD_SL, (b) is the process when the media type of an optical disk is BD_DL Indicates. It is a figure which shows the specific media type discrimination | determination process of an optical disk reproducing device, (a) shows a process in case the media type of an optical disk is BD / DVD_SL, (b) shows the media type of an optical disk BD / CD. Processing in the case of. It is a figure which shows the specific media type discrimination | determination process of an optical disk reproducing device, (a) shows a process in case the media type of an optical disk is BD / DVD_DL, (b) shows the media type of an optical disk BD / DVD_SL. Processing in the case of / CD is shown. As a specific media type determination process of the optical disc playback apparatus, a process when the media type of the optical disc is BD / DVD_DL / CD is shown. As an application example of media type discrimination processing, it is a flowchart showing processing for discriminating the media type of an optical disc using a CD laser instead of a DVD laser. FIG. 17 is a diagram illustrating a specific operation of the media type determination process illustrated in FIG. 16, in which (a) illustrates a process when the media type of the optical disc is BD / DVD_SL / CD, and (b) illustrates a media type of the optical disc. Shows processing when BD / DVD_DL.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 13 Optical pick-up 16 RF amplifier 17 Signal processing part 18 Servo circuit 21 CPU
41b BD laser 41c CD laser 41d DVD laser 48, 49 Objective lens 50, 52 Actuator

Claims (12)

Based on the wavelength of irradiation Isa laser light, sequentially, the first recording layer to different depths, the second recording layer, the optical disc reproducing apparatus for reproducing at least one of which is formed an optical disk of the third recording layer,
A light emitting source for emitting the laser light;
An objective lens that focuses the laser light emitted from the light source on a focal point;
A search start position for searching the first recording layer is set between the first recording layer position and the second recording layer position on the optical disc, and the focal point of the objective lens is set to the first position from the set search start position. A first search for performing a first search for searching for the first recording layer by controlling the position of the objective lens so as to move to a preset first driving limit across the position of one recording layer And
The position of the objective lens is controlled so that the focal point moves from the first drive limit to a preset second drive limit beyond the third recording layer position, and the first recording layer A second search unit for performing a second search for searching the third recording layer,
When the first search unit performs the first search, the laser beam obtains a reflected signal by reflected light reflected by the first recording layer, and the second search unit acquires the second search signal. A reflected signal acquisition unit that acquires a reflected signal of reflected light reflected by the first recording layer to the third recording layer when the laser beam is searched;
The number of reflected signals acquired by the reflected signal acquisition unit when the first search unit performs the first search is the first signal number, and the second search unit performs the second search. When the number of reflected signals acquired by the reflected signal acquisition unit is a second signal number, the optical disc is based on the difference between the first signal number and the second signal number . A media type discriminating unit for discriminating whether or not it has at least one of a recording layer and the third recording layer ;
An optical disk reproducing apparatus characterized by the above. The media type determination unit determines that the optical disk is not present when the first signal number is zero and the second signal number is also zero;
The optical disk reproducing apparatus according to claim 1, wherein: The first recording layer, the second recording layer, and the third recording layer respectively track the laser light emitted by the laser having the first wavelength, the laser having the second wavelength, and the laser having the third wavelength. It has a track that can be tracked,
Using the laser having the second wavelength as the light source, the position of the objective lens is controlled so that the focal point of the objective lens moves from the second driving limit toward the first driving limit. A third search unit for performing a third search for searching the third recording layer and the second recording layer;
After performing the second search, when the third search unit performs the third search, the first recording layer of the third recording layer or the second recording layer is detected, A tracking control unit that performs tracking so that the laser beam follows the track on which the data of the optical disc is recorded, using the laser of the second wavelength as the light source;
The media type determination unit
When the number of the first signals is zero and the number of the second signals is 1 or more, the tracking control unit performs tracking, and the laser beam of the second wavelength follows the track and is tracking on. When the media type of the optical disc is determined to be a media type having only the second recording layer and tracking is not turned on, the media type of the optical disc is a media type having only the third recording layer. To determine,
The optical disk reproducing apparatus according to claim 1 or 2 , characterized in that The media type determination unit
When the number of the first signals acquired by the reflected signal acquisition unit is 1 or more, a difference between the number of the first signals and the number of the second signals is obtained, and when the obtained difference is zero, the optical disc Discriminating that the media type is a media type having only the first recording layer,
The optical disk reproducing apparatus according to claim 1, wherein the optical disk reproducing apparatus is an optical disk reproducing apparatus . The media type determination unit
When the number of the first signals acquired by the reflected signal acquisition unit is 1 or more, the difference between the number of the first signals and the number of the second signals is obtained. When the obtained difference is 1, the optical disc Discriminating that the media type is a media type having the first recording layer and the second recording layer or a media type having the first recording layer and the third recording layer.
The optical disk reproducing apparatus according to claim 1, wherein the optical disk reproducing apparatus is an optical disk reproducing apparatus . The first recording layer, the second recording layer, and the third recording layer respectively track the laser light emitted by the laser having the first wavelength, the laser having the second wavelength, and the laser having the third wavelength. It has a track that can be tracked,
Using the laser having the second wavelength as the light source, the position of the objective lens is controlled so that the focal point of the objective lens moves from the second driving limit toward the first driving limit. A third search unit for performing a third search for searching the third recording layer and the second recording layer;
After performing the second search, when the third search unit performs the third search, the first recording layer of the third recording layer or the second recording layer is detected, A tracking control unit that performs tracking so that the laser beam follows the track on which the data of the optical disc is recorded, using the laser of the second wavelength as the light source;
The media type determination unit
When the first signal number is 1 or more and the difference between the first signal number and the second signal number is 1, when the tracking control unit performs tracking, the second signal is added to the track. When the laser light of the wavelength of the tracking follows and tracking on, it is determined that the media type of the optical disc is the media type having the first recording layer and the second recording layer, and when tracking on is not performed, Determining that the media type of the optical disc is a media type having the first recording layer and the third recording layer;
6. An optical disk reproducing apparatus according to claim 5, wherein The media type determination unit
When the number of the first signals acquired by the reflected signal acquisition unit is 1 or more, the difference between the number of the first signals and the number of the second signals is obtained, and when the obtained difference is 2, the optical disc A media type having the first recording layer and a plurality of the second recording layers, or a media type having the first recording layer, the single second recording layer, and the third recording layer. Determine that there is,
The optical disk reproducing apparatus according to claim 1, wherein the optical disk reproducing apparatus is an optical disk reproducing apparatus . The first recording layer, the second recording layer, and the third recording layer respectively track the laser light emitted by the laser having the first wavelength, the laser having the second wavelength, and the laser having the third wavelength. It has a track that can be tracked,
Using the laser having the second wavelength as the light source, the position of the objective lens is controlled so that the focal point of the objective lens moves from the second driving limit toward the first driving limit. A third search unit for performing a third search for searching the third recording layer and the second recording layer;
After performing the second search, when the third search unit performs the third search, the first recording layer of the third recording layer or the second recording layer is detected, A tracking control unit that performs tracking so that the laser beam follows the track on which the data of the optical disc is recorded, using the laser of the second wavelength as the light source;
The media type determination unit
When the first signal number acquired by the reflected signal acquisition unit is 1 or more and the difference between the first signal number and the second signal number is 2, the tracking control unit performed tracking. Sometimes when the laser beam of the second wavelength follows the track and tracking is turned on, the media type of the optical disc is a media type having the first recording layer and the second recording layer of multiple layers. When the tracking is not turned on, it is determined that the media type of the optical disc is a media type having the first recording layer, the single second recording layer, and the third recording layer.
The optical disk reproducing apparatus according to claim 7, wherein: The media type determination unit
When the first signal number acquired by the reflected signal acquisition unit is 1 or more, the difference between the first signal number and the second signal number is obtained. When the obtained difference is 3, the optical disc Discriminating that the media type is a media type having the first recording layer, the multilayer second recording layer, and the third recording layer;
9. An optical disk reproducing apparatus according to claim 1, wherein The media type determining unit, on the basis of the first signal number or the second number of signals, the media type of the optical disc, multilayer or the first recording layer is a media type of the optical disk of a single layer To determine whether the media type of the optical disc
The optical disk reproducing apparatus according to claim 1, wherein the optical disk reproducing apparatus is an optical disk reproducing apparatus . Based on the wavelength of irradiation Isa laser light, sequentially, the first recording layer to different depths, the second recording layer, the media type discrimination of the optical disc reproducing apparatus for reproducing at least one of which is formed an optical disk of the third recording layer A method,
An objective lens for setting a search start position for searching the first recording layer between the first recording layer position and the second recording layer position on the optical disc, and condensing laser light from the set search start position. The first search for searching the first recording layer is performed by controlling the position of the objective lens so that the focal point moves across the first recording layer position to a preset first driving limit. Steps to perform,
The position of the objective lens is controlled so that the focal point moves from the first drive limit to a preset second drive limit beyond the third recording layer position, and the first recording layer Through a second search for searching the third recording layer;
When the first search is performed, a reflected signal from the reflected light reflected from the first recording layer is acquired by the laser beam, and when the second search is performed, the laser beam is the first laser beam. Obtaining a reflected signal by reflected light reflected from the recording layer to the third recording layer;
When the first search is performed, the number of reflected signals acquired when the second search is performed is defined as the first signal number and the second signal number, respectively. Determining whether the optical disc has at least one of the second recording layer and the third recording layer based on a difference from the number of signals of 2.
A media type discrimination method for an optical disc playback apparatus . Based on the wavelength of irradiation Isa laser light, sequentially, the first recording layer to different depths, the second recording layer, the third recording layer of at least one computer with the optical disc reproducing apparatus for reproducing the formed optical disc ,
A search start position for searching the first recording layer is set between the first recording layer position and the second recording layer position on the optical disc, and the focus of the objective lens of the optical pickup is determined from the set search start position. A procedure for performing a first search for searching the first recording layer by controlling the position of the objective lens so as to move to the first driving limit set in advance across the position of the first recording layer;
The position of the objective lens is controlled so that the focal point moves from the first drive limit to a preset second drive limit beyond the third recording layer position, and the first recording layer To a second search for searching the third recording layer;
When the first search is performed, the laser beam of the optical pickup obtains a reflected signal from the reflected light reflected by the first recording layer, and when the second search is performed, the laser beam is A procedure for obtaining a reflected signal by reflected light reflected by the first recording layer to the third recording layer;
When the first search is performed, the number of reflected signals acquired when the second search is performed is defined as the first signal number and the second signal number, respectively. A procedure for determining whether the optical disc has at least one of the second recording layer and the third recording layer based on a difference from the number of signals of 2;
A program for running

Images