JPH09282785A - Optical disk reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change a signal and a data processing circuit over to their adapted state to a disk in accordance with a kind of the disk. SOLUTION: This device is constituted to reproduce signals recorded on plural kinds of disks via a pickup 21 respectively. In this case, when a beam emitted from the pickup 21 is changed in numerical aperture or wavelength to correspond to a disk 11 as a reproducing object, characteristics of a signal processor 25 and compensating amplifiers 27 and 33 are set in their state corresponding to the disk 11 by a system control part 100 in accordance with this change.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc reproducing apparatus, and more particularly to a plurality of optical systems having different beam spot sizes or different wavelengths, and a plurality of optical systems corresponding to the plurality of optical systems. This is an apparatus which is associated with a signal processing system having signal processing characteristics so that appropriate reproduction and recording can be performed according to the type of the optical disc.

[0002]

2. Description of the Related Art A conventional optical disc reproducing apparatus for music has a size (diameter 12 cm, 8 cm) of an optical disc.
Etc.), the movement range can be switched to the pickup device. However, this reproducing apparatus is premised on that the recorded signal system is the same for all optical discs and is standardized.
Therefore, only the size of the optical disc may be focused on to design the disc corresponding function.

However, in recent years, various types of optical discs have been developed, and optical discs having different signal recording systems and standards are mixed. Conventionally, a dedicated reproducing device corresponding to each optical disc has been developed, but this is inconvenient for the user.

[0004]

As described above, these days,
Various optical discs with different signal recording methods and standards are mixed. Therefore, a device capable of recording / reproducing corresponding to various optical discs has been demanded.

Therefore, the present invention provides a reproducing apparatus for an optical disc in which the characteristics of the read signal on the signal processing side are also switched in accordance with the switching of the characteristics of the optical system so that appropriate signal processing can be obtained. The purpose is to do.

Further, according to the present invention, a plurality of optical systems and a signal processing system having a plurality of signal processing characteristics corresponding to the plurality of optical systems are prepared, and any one optical system and any one signal processing characteristic are provided. It is an object of the present invention to provide an optical disc reproducing apparatus capable of performing appropriate reproduction and recording according to the type of the optical disc by corresponding to the above.

It is another object of the present invention to provide an optical disc reproducing apparatus capable of properly discriminating different types of optical discs.

According to the present invention, in an optical disc reproducing apparatus for reproducing a signal recorded on a disc from a plurality of discs having different track pitches through an optical pickup, the optical pickup is selected according to the disc to be reproduced. The numerical aperture changing means for changing the numerical aperture of the beam emitted from the beam, and the characteristics of the signal processing system connected to the subsequent stage of the pickup are reproduced in response to the changing of the numerical aperture of the beam by the numerical aperture changing means. And a signal processing system changing means for changing according to the disc.

Further, according to the present invention, when a plurality of optical systems having different pickup characteristics and any one of the plurality of optical systems are selected, the selection information is taken in and signal processing corresponding to the selected optical system is performed. And means for constructing a system.

By such means, it is possible to construct an appropriate signal reproduction path for each type of optical disc or the type of signal recorded on the disc.

The plurality of optical systems according to the present invention are optical systems in which beam spot sizes are different or wavelengths are different.

The optical system switches between the three-beam system and the one-beam system. When a disc having a pit of the first size is reproduced, the pit of the three-beam system and the pit of the first size are used. When the disc with the second small pit is reproduced, the one-beam system is switched to.

In the optical pickup device of the present invention, a plurality of optical systems having different beam spot sizes or different wavelengths are made to oppose an optical disk having one of the plurality of optical systems mounted thereon. A switching means, a detecting means for detecting the reflected light of the beam applied to the optical disc, a focus adjusting mechanism for the optical disc, and a tracking adjusting mechanism for the optical disc are mounted. The signal processing unit can switch the processing characteristic according to the type of the optical disc, and reproduces the signal recorded on the optical disc by using the signal detected by the detection means. Here, the focus servo means can switch the servo characteristics according to the type of the optical disc, and generates a focus error signal using the signal detected by the detection means and feeds it back to the focus adjustment mechanism. The tracking servo means can switch the servo characteristics according to the type of the optical disc, and generates a tracking error signal using the signal detected by the detection means and feeds it back to the tracking adjustment mechanism. Then, the system control means includes an optical system setting means for causing the switching means to select an arbitrary optical system adapted to an arbitrary optical disc as an optical system to be used among the plurality of optical systems, and the optical system setting means. When selecting any of the optical system,
It has a system setting unit for switching the signal processing unit, the focus servo unit, and the tracking servo unit to a processing characteristic and a servo characteristic corresponding to the arbitrary optical disc, and an optical disc type discriminating unit.

According to the above-mentioned means, it is possible to adaptively set the optical system suitable for reading the recorded signal and the processing characteristic of the reproduced signal according to various optical discs.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

First, the structure of currently mixed optical discs will be described. FIG. 1 shows the cross sections of various optical disks in principle. FIG. 1A shows a conventional compact disc for music (so-called CD).
And the thickness is defined as 1.2 mm. FIG.
(B) is an optical disc that realizes high-density recording and records data-compressed video code and audio code, and there is also an ultra-high-density optical digital video disc that can be recorded and reproduced (hereinafter, these discs. Is referred to as a DVD). Therefore, this DVD is a so-called read-only DVD-RO.
M and a recordable DVD-RAM. The one shown in FIG. 1B has a single-layer reading and recording surface.
The one shown in (C) is a DVD-ROM having a two-layer structure in which two sheets are further laminated. The total thickness of each disk is defined as 1.2 mm, and the substrate thickness is defined as 0.6 mm.
The diameters of CD and DVD are both specified to be 12 cm / 8 cm.

FIG. 2 is an enlarged view of the recording surface of the above-mentioned optical disc, which is shown from the back side. 2A shows the structure of the recording surface of the CD, FIG. 2B shows the structure of the recording surface of the DVD-ROM, and FIG. 2C shows the structure of the recording surface of the DVD-RAM. The figure also shows the disk substrate thickness, pit width, and track width.

As described above, some optical disks have different track pitches, and some have different recording formats.

FIG. 3 shows a reproducing apparatus to which the present invention is applied.

Reference numeral 11 denotes an optical disk, which is rotationally driven by a disk motor 12. Reference numeral 21 denotes an optical pickup device, which is controlled to move in the radial direction of the disc by a feed motor 22. Optical pickup device 21
Is equipped with a system in which the optical system is switched by changing the numerical aperture of the beam so that the beam for CD and the beam for DVD can be switched and irradiated. Therefore, the optical system of the optical pickup device 21 can be switched and selected according to the optical disc to be reproduced or recorded.

The reason for switching the optical system in this way is that the CD
Since the substrate thickness, the pit width, and the track width are different between DVD and DVD, an appropriate beam spot is required to obtain effective reflected light signal characteristics. This is because the DVD requires a finer beam spot than the CD, and the pit depth is shallower than that of the CD, so that a beam spot corresponding to this is required. The switching of the beam spots may be realized by switching beams having different wavelengths.

That is, the optical pickup device 21 is equipped with at least the following means. That is, a plurality of optical systems having different beam spot sizes or different wavelengths and any one of the plurality of optical systems are selected, and the selected optical system is used as an optical disc mounted on the device. A switching mechanism to face each other, a photodetector element unit for detecting the reflected light of the beam applied to the optical disc, a focus adjustment mechanism for the optical disc, and a tracking adjustment mechanism for the optical disc are mounted. There is. Examples of the plurality of optical systems having different wavelengths include wavelengths of 650 nm, 780 nm, 685 nm and the like.

The detection signals obtained from the plurality of photodiodes forming the photodetector element section of the optical pickup device 21 are input to the preamplifier 23, respectively. From the preamplifier 23, the output (A, B,
C, D) composite signal HF, focus error signal,
It is possible to obtain the (A + C) signal, the (B + D) signal, and the (EF) signal which is the tracking error signal for the CD among the detection signals of the four-division photodiode.

The composite signal HF is waveform-equalized via the equalizer 24 and input to the DVD / CD signal processing section 25.
The DVD / CD signal processing unit 25 switches to the DVD processing mode or the CD processing mode according to a control signal from the system control unit 100 described later. Of course, the equalizer and the signal processing unit may be separately prepared for the DVD and the CD. Although not shown, the control unit 1 may be used for other drive amplifiers of the servo system depending on the type of disk used.
A suitable gain setting signal may be given from 00.

In the above system, the sub-beam / main-beam method is adopted during CD reproduction, and the detection signals A to
It is preferable that F is used, the one-beam method (main beam method) is used during DVD reproduction, and the detection signals A to D are used.

The sub-beam / main-beam system is specifically a system including a 3-beam system and a 1-beam system.
The three-beam system is a system in which reflected lights are picked up by at least a four-division photodiode and diodes arranged before and after the diode and the outputs A to F are used, as will be described later. Is 4
A method will be described in which reflected light is picked up by a split diode and the outputs A to D are used.

The focus error signal is input to the S-shaped level detector 26B via the noise removing filter 26A and also to the compensation amplifier 27. The output of the compensation amplifier 27 is input to the drive circuit 28 and becomes a focus control signal, which is given to the focus control mechanism of the optical pickup device 21.

In the above system, for example, when the system control unit 100 selects an optical system and performs a switching operation, at the same time, or in conjunction with the switching, a servo system and a signal connected to the subsequent stage of the pickup device. The characteristic of the processing system or the route itself is automatically switched.

FIG. 4 shows how the focus error signal changes according to the focus state. This change is detected by the S-shaped level detector 25. Although the focus error signal is generated from the detection signal of the main beam in the embodiment, it is not limited to the main beam and may be generated from the detection signal of the sub beam. This is because the detection signal of the sub beam also has a level difference compared to the main beam, but has a similar S-shaped characteristic depending on the focus state. In this case, the sub-beam detection element may also be a 4-division detector.

The information on the detection level detected here is input to the system controller 100. System control unit 10
0 uses the S-shaped detection level to determine the type of the optical disc as described later.

From the preamplifier 23, which will be described in detail later, (A + C) signal, (B + D) signal, and (EF) signal detected by the photodiode of the optical pickup device 21 are obtained, but (A + C). The signal and the (B + D) signal are input to the phase difference detector 31. This phase difference detector 31
Detects a difference between the (A + C) signal and the (B + D) signal to obtain a tracking error signal for DVD.
The tracking error signal for this DVD is the switch 3
It is supplied to one of the two. Further, the (EF) signal is a tracking error signal for CD, and this signal is also supplied to the other side of the switch 32. The switch 32 is switched according to the system setting mode of the system control unit 100 and the disc type determination signal, and is used as the disc 11 for the CD
If is mounted, a tracking error signal for CD is selected, and if a DVD is mounted, a tracking error signal for DVD is selected. The signal derived from the switch 32 is input to the compensation amplifier 33. The output of the compensating amplifier 33 becomes a tracking control signal via the drive circuit 34 and is given to the tracking control mechanism of the optical pickup device 21. Further, a signal with a large control amount is fed through the drive circuit 35 to the feed motor 22.
Is supplied to.

The DVD / CD signal processing section 25 detects the frequency and phase of the reproduction signal and demodulates the control information contained in the reproduction signal. Generating a motor control signal. The disk motor control signal is applied to the disk motor 12 via the drive circuit 36 to form a servo loop.

From the system controller 100, the equalizer 2
4. A control signal is given to the DVD / CD signal processing section 25. This control signal is used by the equalizer 24 and the DVD / CD.
The equalization characteristic, the processing clock, and the operating state of the signal processing unit 25 can be switched according to the settings of the CD mode and the DVD mode. In addition, the system control unit 100 can switch and set the response characteristics and operation modes of each servo system.

A control signal is applied to the switch 32 from the system controller 100. This control signal is D
In the VD mode, the switch 32 takes out the tracking error signal from the phase difference detector 31, and in the CD mode, the switch 32 takes out the (EF) signal as the tracking error signal. The system control unit 100 also supplies a control signal to the compensation amplifier 33 in the tracking servo loop. This control signal is for switching control of the loop characteristic of the tracking servo loop, and is specifically a gain switching signal. The system control unit 100 also supplies a control signal to the compensation amplifier 27 in the focus servo loop. This control signal is also a gain switching signal and controls switching of loop characteristics of the focus servo loop.

Furthermore, the system control section 100 can forcibly stop the servo operation or set the compulsory operation state instead of the automatic operation while the disk determination operation is being performed. .

FIG. 5 shows the arrangement of the photodiodes A to F constituting the photodetector of the optical pickup device 21 and the inside of the preamplifier 23. Each photodiode A
The output of each of ~ F is a buffer amplifier 23a ~ 23f.
Has been introduced to.

The respective A to F signals output from the buffer amplifiers 23a to 23f are calculated as follows.

The adder 231 produces the (A + B) signal, and the adder 232 produces the (C + D) signal. Then, the subtractor 233 uses the (A + C) signal from the adder 231 and the (C + D) signal from the adder 232.
(A + B)-(C + D) signal is generated. This (A
The + B)-(C + D) signal is used as a focus error signal.

Adder 234 produces the (A + C) signal,
The adder 235 produces the (B + D) signal. The (A + C) signal and the (B + D) signal are separated by the phase difference detector 3
1 is input. The output of this phase difference detector 31 is DV
It is used as a tracking error signal for D. That is, when the device is in the DVD mode, the switch 321 is on-controlled. On the other hand, the (EF) signal obtained based on the detection signal of the sub beam is ignored by turning off the switch 322.

The (A + C) signal and the (B + D) signal are also input to the adder 236. This adder 235 is (A
+ B + C + D) signal (referred to as HF signal) is generated.

The E signal and the F signal are input to the adder 237. The (EF) signal is obtained from the adder 237. This (EF) signal is used as a tracking error signal for CD. That is, the switch 322 is on-controlled when the device is in the CD mode.

In the above system, any one of the plurality of optical systems is first set under the control of the system controller 100. For example, assume that the CD mode is set. Then, the system control unit 100 recognizes that the optical system has been set to the CD mode, and automatically switches to the CD mode so that other related signal processing systems also correspond. The signal processing system includes a DVD / CD signal processing unit 25,
There is a servo system. On the contrary, it recognizes that the optical system has been set to the DVD mode, and automatically switches to the DVD mode so that other related signal processing systems also correspond.

When a large number of discs of different types are mixed as described above, the reproducing and recording apparatus is provided with a plurality of optical systems so as to be compatible with various discs, and switches to a plurality of characteristics. A signal processing system that can be used, or a signal processing system corresponding to each optical system will be prepared.

Here, the operation of the system when the disc is loaded in the reproducing and recording apparatus will be described.

In the manual mode, the user can input the type of disk to be used in the reproducing and recording apparatus in advance from the operation unit. The disc type information in this case is input to and grasped by the system control unit 100. Based on this grasping information, the system control unit 10 determines the optical system and the signal processing system corresponding to the disc type as described above.
It will be set by 0.

Next, in the automatic mode, when a disc is loaded, an automatic discriminating function for discriminating the disc type, for example, operates. The system control unit 100 recognizes the discrimination information obtained by the operation of the automatic discrimination function. Based on this grasping information, the system control unit 100 sets the optical system and the signal processing system corresponding to the type of the disc as described above. Of course, even after the user discriminates the type of the disc from the beginning and determines and inputs the first system set state by the operation, the automatic discrimination device may operate. In the case of such a function, it corrects the disc recognition error of the user. Also, when the disc is inserted, it may be unconditionally set to a predetermined initial state, or may be set to the state used immediately before that.

In the above description, when the plurality of optical systems and the plurality of signal processing characteristics of the signal processing system are made to correspond to each other in a one-to-one relationship, the optical system is set first. It goes without saying that they may be selected and set first, or they may be set simultaneously.

The following circuits exist as a signal processing system. A reproduction signal processing unit that demodulates and reproduces a recording signal of an optical disc using a pickup signal from the pickup device, and a servo system that performs focus control of the optical system of the pickup device using the pickup signal from the pickup device, A tracking servo circuit that can switch the characteristics, and a servo system that performs tracking control of the optical system of the pickup device using the pickup signal, and is a tracking servo circuit that can switch the characteristics.

Next, an automatic method for determining which type of disk is mounted as the disk 11 will be described.

First, the optical system (lens) of the optical pickup device 21 is set to either one. That is, the optical pickup device 21 is initially in either mode (C
It is always set to D mode or DVD mode). Further, at this time, the system control unit 100 also sets the focus servo and tracking servo systems to a mode corresponding to the mode initially set in the optical system. The same applies to the signal processing unit 25, and the mode corresponding to the mode initially set in the optical system is set.

Next, a single-layer disc such as a CD or a DVD,
A two-layer disc of DVD-ROM and DVD-RAM has a different reflectance when irradiated with a light beam. As described above, the phenomenon that the reflectance of the light beam varies depending on the type of the disk is effectively used.

For a single-layer disc such as a CD or a DVD, 60
The reflectivity is about 70%, the reflectivity is 25 to 30% for a dual-layer DVD-ROM disc, and 1 for DVD-RAM.
Layer discs have a reflectivity of 20% or less.

Therefore, for example, when the focus error signal is at the high level H, it is determined that a single-layer disc of CD or DVD is mounted, and when the focus error signal is at the low level L, the DVD-ROM disc is read. It can be determined that a two-layer disc and a two-layer disc such as a DVD-RAM are mounted.

Further, first, the lens is first set at a position farther from the disc, and the lens is gradually brought closer to the disc, depending on the number of focal planes obtained from the focus signal.
It is also possible to determine whether the disc is a dual-layer disc (DVD-ROM dual-layer disc or single-layer disc (CD or DVD single-layer disc). At this time, the disc may be stopped without rotating, In this case, it is preferable that the rotation servo system is not automatic but performs forcible rotation control because turning on the servo system may cause runaway. It is.

Further, as the rotational speed at the time of slowly and uniformly rotating, the inner peripheral rotational speed of CLV or the assumed maximum rotational speed of the disk is preferable. This rotation method is the same when a tracking error signal to be described later is obtained for disc discrimination. Next, the focus servo is turned on and the focus is set.

Next, reading is performed to detect the RAM identification signal.

FIG. 6 shows a signal recording state of the DVD-RAM. In the case of a DVD-RAM, as shown in FIG. 6, a pit identification signal longer than the maximum length of data pits is recorded on the inner peripheral portion of the disc. Therefore, it is possible to determine that the disc is a DVD-RAM by detecting this identification signal. In order to identify the disc as a DVD-RAM disc, the identification signal of the pit shorter than the minimum length of the data pit may be recorded on the inner or outer periphery of the disc without being limited to this method. In short, it suffices that there is a data pit whose length exceeds the range in which the length of the data pit as the identification signal changes.

By the above determinations, it is possible to discriminate between (1) a single-layer disc of CD or DVD, (2) a dual-layer disc of DVD-ROM, and (3) a single-layer disc of DVD-RAM. is there. In the case of a dual-layer disc of DVD-ROM, signal processing and servo system and optical system settings are performed accordingly. For a DVD-RAM single-layer disc, a recording system is constructed and an optical system and a servo system are set.

Next, the magnitude of the tracking error signal is judged.

The following output is obtained as the tracking error signal.

(1) The initial setting of the device is the CD mode,
If the disc is a CD, the tracking error signal is large, and if the disc is a DVD, the tracking error signal is small. This is because the track pitch of the DVD is small and the beam spot is large, so that the tracking error signal changes little.

(2) If the initial setting of the device is the DVD mode and the disc is a DVD, the tracking error signal is large, and if the disc is a CD, the tracking error signal is small. CD with a small beam spot
This is because the track width is large, and even if a track error occurs, it does not change significantly.

As a result, various discs can be discriminated.

(First Disk Judgment Program) FIG. 7 shows a flowchart of the disk judgment program stored in the system controller 100.

When the disc discriminating function is started, initial setting is automatically performed. The optical system, the signal processing unit, and the servo system are set for CD. Next, the lens is set to a predetermined position, the focus error signal is extracted, and the S-shaped level is determined (steps A1 to A).
4). Here, if the S-shaped level is high level H, it is determined to be a CD or a single-layer DVD, then the focus is adjusted, the disc is rotated, and the determination of the tracking error signal is performed (steps A5 to A7). ). An (EF) signal is used as the tracking error signal. If this tracking error signal is larger than a predetermined value, it is determined to be CD, and if it is smaller, it is determined to be DVD. The predetermined value can be obtained by previously determining the level for discriminating between CD and DVD by experiments or the like.

In step A4. If the S-curve level is low level L, a dual-layer DVD-ROM or DV
It is determined to be the D-RAM, the focus is adjusted next, and the disc is rotated (steps A10 and A1).
1). Then, the presence / absence of the identification signal is determined. When the identification signal (shown in FIG. 6) is present, it is determined to be a DVD-RAM, and when it is not present, it is determined to be a DVD-ROM (step A12).

During the above process, the disk is rotated when tracking is performed. At this time, CLV is used.
(Constant Linear Velocity) control is off,
Forced constant rotation control is realized. This is CL
This is because when the V control operates, the rotation servo of the disk and the tracking servo system may run away if the setting state of the device does not match the type of the disk. Also, before tracking is performed, a disc discriminating process (step A
4) is arranged.

Performing the disc discriminating step before the tracking control has the following meanings. DVD-R
In the case of OM, the groove depth is λ / 4, and in the case of DVD-RAM, the groove depth is λ / 8. For this reason, if the disc type is not clear, normal tracking control cannot be obtained. And, as described above, the rotation servo system and the tracking servo system of the disk may run away.

(Second Disk Judging Program) FIG. 8
Shows a flowchart of yet another disk determination program stored in the system control unit 100. This program is different from the program of FIG. 7 only in the initial setting conditions. That is, in this program, the optical system is set to D as the initial setting after step A1.
A lens for VD is set, and a servo system and a signal processing system are also set for DVD.

When the initial settings are made in this way, step A
The output of the phase difference detector 31 is used as the tracking error signal used in FIG. Then, with the CLV control turned off, the disk is rotated to check the magnitude of the tracking signal. If the tracking signal is large, it is determined to be DVD, and if it is small, it is determined to be CD. The other steps are shown in FIG.
Since the same processing as the above processing is performed, the description will be omitted.

(Third Disc Judgment Program) FIG. 9
Shows a flowchart of another disk determination program stored in the system control unit 100. In the program shown in FIGS. 7 and 8, step A4
And the disc is a dual layer DVD-ROM or single layer DVD-
After determining that the disc is one of the RAM, the identification signal is searched to determine which disc is the disc. However, in this program, it is determined whether or not there are two focal planes of the focus signal by gradually moving the lens closer to the disc from a position away from the disc (steps C1 and C2). If there are two focal planes of the focus signal, it is a dual-layer disc (DVD-ROM),
If there is one, it means a single-layer disc (DVD-RAM).

(Fourth Disc Judgment Program) FIG.
Shows a flowchart of another disk determination program stored in the system control unit 100. According to this determination program, after first performing the initial setting, the lens is gradually moved closer to the disc from a position away from the disc, and whether or not there are two focal planes of the focus signal, that is, the S-curve detection signal is detected twice. It is determined whether it can be obtained (steps D1 to D4). When the focus signal has two focal planes, a dual-layer disc (double-layer DVD-
It is determined to be a ROM) (step D5). Next, if there is one focal plane, it is a single-layer disc, CD, DV
It is either a D-RAM or a single-layer DVD-ROM.

Then, the S-curve level of the focus error signal is judged again, and if the S-curve level is the high level H, the disc is a CD or a single-layer DVD-ROM (steps D6 and D7). If the S-curve level is high,
The same determination process as in steps A5 to A7 of FIG. 8 is performed. When the S-curve level is low level, a single layer DVD-
ROM or DVD-RAM (step D
8) and thereafter, by the same processing as steps A11 and A12 of FIG. 7 and FIG. 8, a single-layer DVD-ROM, DVD-R
The AM is discriminated.

FIG. 11 shows another embodiment of the present invention.

Although the above-mentioned embodiments all show the method of automatically discriminating a disc, a discriminating method in which a user's operation is added may be used. The disc may be discriminated by the disc selection button of the player when the disc is set in the player, but the following method may also be used.

In FIG. 11, reference numeral 41 is an operation input interface, which receives an operation signal from the remote controller 42 and supplies it to the system controller 100. Now, when the user starts reproduction or recording, the apparatus displays on the display unit a request for inputting a disc discrimination signal.
The display unit may be a TV screen, the display unit of the remote controller 42, or a warning sound may be added. If the disc identification signal has already been input, the process moves to the next step.

(Fifth disc determination program)
FIG. 12 shows an example of a flowchart of the above system.

When the apparatus is started, the disc identification signal is requested through the display section (audio may be added) (steps E1 to E2). When the user inputs the discriminating signal of the disc, the system automatically starts,
The disk is rotated (however, the normal servo operation is suppressed), and signal reproduction, focus servo, and tracking servo are activated (steps E3 and E4).
Then, it is judged whether or not there is a large amount of error in the reproduction signal, and if there is no error, for example, a safety display in blue is displayed on the display section, and reproduction or recording is executed (steps E5, E
6). However, if there is an error in the servo signal or an error in the reproduction signal, a warning is issued to re-input the disc identification on the display (step E7). Each time the user issues a warning, he or she inputs the disc discrimination input one after another, and controls the device so that the disc correspondence type is switched. Then, when the blue safety display is displayed on the display unit, the discrimination input is stopped.

(Sixth Disc Judgment Program) FIG.
Shows another example flow chart of the above system.

In this flowchart, the apparatus itself automatically specifies the disc discriminating signal cyclically, executes the reproduction according to the disc discriminating signal, judges whether or not a large number of errors are present in the reproduced signal, and If there is no
It is determined that the currently mounted disc corresponds to the disc discriminating signal that has been set, and the reproduction process is started (steps F1 to F5). But,
If a large number of errors occur, determine whether all the settings for the expected disk type have been tried. If not, return to step F2 and set the next settings again. View. When it is determined in step F6 that all the settings for the assumed disc type have been tried, it is determined that a foreign substance is mounted and a warning is issued (steps F6, F
7).

(Seventh Disc Judgment Program) FIG.
Shows an example of yet another flowchart of the above system.

In this flowchart, first of all, FIG.
This is a method for searching whether there is an identification signal indicating the DVD-RAM as shown in FIG. This is because it is important to determine whether or not the disc is a recordable disc in order to prevent a recording error.

That is, after the start, the disc is slowly rotated to determine whether there is an identification signal. If there is an identification signal, it is determined to be a DVD-RAM (step A).
1, G1-G3). If there is no identification signal, it is necessary to distinguish between a CD or a single-layer DVD-ROM and a double-layer DVD-ROM. Therefore, as described above, the system is initialized (step G4), the S-curve level is detected (steps G5 and G6), and if the S-curve level is lower than a predetermined value, it means that the DVD-ROM has two layers. judge. S
If the character level is higher than the specified value, CD or D of 1 layer
It is a VD-ROM (step G8). Therefore, the focus is set, the disk is rotated about a half rotation, and the tp tracking servo is applied. In this case, the rotation servo is turned off and forced rotation is performed. This is to prevent runaway of disk rotation. With the tracking servo applied, it is determined whether the tracking error signal is large or small. The tracking servo is set for DVD or CD in correspondence with the initial setting. Depending on this initial setting condition and the magnitude of the tracking error signal,
CD or DVD can be distinguished (step G9,
G10).

In the above description, the process up to the determination of the disc type has been described. However, after this, the system control means naturally adjusts the signal processing unit and the focus so as to match the determined disc type. The servo means and the tracking servo means are reset, and the system is controlled so that they can be reproduced or recorded.

Further, this system may be provided with the following functions.

That is, it is a function of determining whether or not the disc is a disc desired by the user when the disc type is discriminated. That is, the user
If the user intends to mount the VD but accidentally mounts the CD, the reproducing apparatus automatically switches to the CD reproducing mode and starts the reproducing operation. Then user D
Even though I think that the VD is installed, there are cases where no image appears on the display. In such a case, the user may misunderstand that the playback device is out of order. In order to prevent such misunderstanding, the user can input the type information of the disc to be reproduced through the operation device, and compare the result of the automatic discrimination with the input information. The information may be displayed on the display unit.

In the above description, the function of FIG. 13 determines that the type of the disc loaded in the reproducing device is different from the type of the disc that the reproducing device is trying to reproduce by determining the error amount of the reproducing signal. This is the function to determine.

This function can be used in combination with the function described with reference to FIGS. That is, first, it is determined whether or not the error amount is large by the function of FIG. 13, the disc type is automatically discriminated, and then the automatic discriminating function shown in FIGS. 7 to 10 is combined. . In this way, when a foreign substance is loaded, detection can be performed early.

The disc discrimination described above utilizes the property of the disc, but in the case of discriminating whether or not the disc mounted is appropriate according to the amount of detected noise, the following means may be used.

FIG. 15 shows an example of a flowchart of the disc discrimination processing of the above system.

That is, when the disc is loaded, the disc rotation is automatically started (steps H1 and H2), and the servo is turned off. Further, in the optical system, a focus that has been initialized in advance is set, and further, the beam characteristics corresponding to the assumed disk are set (step H3). Then, first, it is determined whether or not there is an identification signal indicating the DVD-RAM as shown in FIG. 6 (step H
4). If this identification signal is detected, the DVD-RA
Since it is M, the recording is ready, and a message to that effect is displayed on the front of the playback device (step H5).

When the identification signal is not detected, the reproducing process is actually executed (step H6). If there is a large amount of error in the reproduction signal, it is determined that the current disc is not the disc of the type set by the reproduction device (step H7). Then, the mode of the disc of the next type is switched to and the reproducing process is performed again (step H8).

As described above, the apparatus itself automatically cyclically designates the disc discrimination signal, and the reproduction according to the disc discrimination signal is executed. Then, it is determined whether or not there is a large amount of error in the reproduction signal, and if there is no error, it is determined that the currently installed disc corresponds to the disc discrimination signal that has been set, and the reproduction processing is performed. The process is continued (step H9). However, when a large number of errors occur, it is judged whether or not all the settings of the supposed disk type have been tried (step H10), and if not all, the process returns to step H6. In step H10, if all the settings of the assumed disk type are tried, it is determined that a foreign substance is mounted and a warning is issued (step H11).

In the above description, the initial mode is automatically set when the disc is set in step H3, and the disc type switching designation input information is also automatically designated in step H8. Then, the user may specify one after another by manual operation or remote control operation.

Next, the types of a plurality of optical systems and the switching mechanism used in the above apparatus will be described in detail.

16 and 17 show the optical system of the optical head.

From the semiconductor laser 350, for example, 650
A divergent laser beam having a wavelength of nm is generated.
Normally, when reproducing information, the semiconductor laser 350
A reproducing laser beam having a substantially constant intensity is generated, and at the time of recording information, a recording laser beam having a relatively large light intensity that is intensity-modulated in accordance with recording data is generated. Further, when the recorded information is erased, an erasing laser beam having a substantially constant intensity, which has a light intensity higher than that during reproduction, is generated.

The laser beam emitted from the semiconductor laser 350 is collimated by the collimator lens 352 and is incident on the half prism 353 as a collimated laser beam. The laser beam is the half prism 53.
It goes straight through the inner half mirror 353A and is directed from its exit surface to the objective lens 334 through a first or second opening 354 or 359 described later.

The first and second openings 354 and 359 have the thickness (1.2 mm) of the transparent substrate of the optical disk 11 as described later.
mm (see FIG. 1A) or 0.6 mm (see FIG. 1B and FIG. 1C)), the optical disc 1
The diameter of the light beam directed to 1 is selected according to the thickness of the transparent substrate. The laser beam that passes through the first or second opening 354 or 359 and is focused by the objective lens 334 is
It is directed to the optical disc 11, refracted by the transparent substrate of the optical disc 11 and focused on a reflective layer formed on this transparent substrate, and a beam spot is formed on this reflective layer (recording surface).

Here, when the objective lens 334 is maintained in the focusing state, the minimum beam spot corresponding to the beam waist of the laser beam is formed on the reflective layer. On the reflective layer of the optical disc 11, tracks as information recording areas are formed concentrically or spirally, and physical recording portions such as pits are formed on the tracks. Normally, the track servo mechanism is operated and the objective lens 334 or the optical head is finely moved to maintain the tracking state in which the track is tracked by the laser beam.

At the time of reproducing information, the reproducing laser beam is modulated at the recording portion of the track formed on the reflective layer, and the modulated laser beam is reflected from the reflective layer. Further, at the time of recording information, the recording layer is formed by physically changing the reflective layer in the track with the modulated recording laser beam. Further, at the time of erasing, the physical change given to the recording section by the irradiation of the erasing laser beam on the recording section is restored.

The laser beam reflected from the reflection layer is collected again by the objective lens 334, and similarly, through the first or second aperture 354 or 359, the half prism 3
Returned to 53. The laser beam reflected by the half mirror 353A in the half prism 353 is projected by the projection lens 3
57, the projection lens 357 causes the photodetector 35
It is condensed on 8. During reproduction, the reproduction laser beam modulated in the recording section is converted into a detection signal by the detector 358, and a reproduction signal, a focus signal and a tracking signal are generated from this detection signal by a signal processing circuit (not shown). At the time of recording or erasing, a recording or erasing laser beam is detected by the detector 358, and a focus signal and a tracking signal are generated from the detection signal by the signal processing circuit.

The above-mentioned first and second openings 354, 359.
Is selected according to the structure of the optical disc 11, that is, the thickness of the transparent substrate of the optical disc 11, as shown in, for example, FIG. 16 or 17, and the laser beam directed to the objective lens 34 is limited and used.

For example, in the optical system shown in FIGS. 16 and 17, when a laser beam having a wavelength of 650 nm is generated from the semiconductor laser 350, the transparent substrate has a thickness of 0.6 mm as shown in FIG. In a high density recorded optical disc (eg, DVD), the aperture 354 is selected so that a converging light beam having a numerical aperture of 0.6 larger than that of the light beam passing through the aperture 359 is projected. FIG.
As described above, the laser beam that has passed through the aperture 354 is condensed by the objective lens 334 and irradiated on the reflection layer through the transparent substrate, and a minimum beam spot of 0.9 μm is formed on the reflection layer. And the reflected light from the reflective layer
Although it is detected by the detector 358, the reflected light of the sub beam is ignored at this time as described in FIGS. 3 and 5. Data reading is performed by the so-called 1-beam method.

On the other hand, as shown in FIG. 17, in an optical disc (CD, for example) having a relatively large thickness of the transparent substrate of 1.2 mm, the numerical aperture is 0.36, which is smaller than the light beam passing through the aperture 354. Aperture 359 is selected such that a focused light beam having Therefore, in the optical system shown in FIG. 17, compared with the optical system in which the aperture 354 is selected,
The laser beam that passes through is limited. The laser beam whose beam diameter has been narrowed by passing through this opening 359 is condensed by the objective lens 334 and is irradiated onto the reflective layer through the transparent base having a thickness of 1.2 mm, and the sufficiently small 1.
Form a minimum beam spot of 6 μm. Then, the reflected light from the reflective layer is detected by the detector 358. At this time, the reflected light of the sub beam is also adopted. So-called 3
Data reading by the beam method is executed.

If an optical disk having a relatively large transparent substrate with a thickness of 1.2 mm is reproduced with the optical system shown in FIG. 16 unchanged (the opening 354 is not changed), the transparent substrate is used. When the laser beam passes, the aberration of the laser beam becomes large, and it is not possible to form a minute beam spot on the reflective layer. That is, when the thickness of the transparent substrate of the optical disc 11 is increased, the refractive index of the transparent substrate is larger than that in the air, so that the objective lens 334 is separated from the optical disc 11 in order to keep the objective lens 334 in the focused state. It will be. This means that the focus tolerance of the objective lens 334 has become small, and even if the objective lens 334 slightly moves, the size of the beam spot fluctuates greatly even if the objective lens 334 slightly tilts. In addition, a halo corresponding to a side lobe is generated around the beam spot.

On the other hand, as shown in the optical system shown in FIG. 17, the aperture 3 having a numerical aperture smaller than that of the aperture 354 is used.
When 59 is selected, the laser beam is incident on the transparent substrate in a narrow range from the objective lens 334 even when information is reproduced or recorded from the optical disc having the transparent substrate having a relatively large thickness. Aberration given to the laser beam is small, and a minute beam spot can be formed on the reflective layer. That is, since the light beam whose diameter is limited is focused by the objective lens 334, the depth of focus with respect to the in-focus point increases, in other words, the focus allowable error increases, and the objective lens 334 slightly moves. However, even if the objective lens 334 is slightly tilted, the size of the beam spot fluctuates greatly, and a halo does not occur around the beam spot, so that the beam spot on the reflective layer can be relatively easily minimized. It can be maintained at the beam spot.

FIGS. 18A and 18B show an example of a structure for selecting the openings 354 and 359. FIG. 18A shows a structure in which openings 354 and 359 having different numerical apertures are linearly arranged on the flat plate 60. The flat plate 360 is linearly moved as shown by the arrow to select the openings 354 and 359. FIG.
(B) shows a structure in which openings 354 and 359 having different numerical apertures are arranged on the arc-shaped plate 362 along the arc. The arc-shaped plate 362 is rotated by a predetermined angle as indicated by an arrow, so that the openings 354, 359 are formed.
Is selected. The selection of the openings 354 and 359 is not limited to this structure, and may be a structure in which the openings are limited by a plurality of movable plates like a lens shutter of a camera.

In the above-mentioned embodiment, when an optical disk (DVD) having a transparent substrate having a thickness of 0.6 mm is loaded in the apparatus, an aperture is formed so as to project a converging light beam having a numerical aperture of 0.6. 354 is selected and the thickness of the transparent substrate is 1.
When a 2mm optical disc (CD) is loaded in the device,
Aperture 359 is preferably selected and used to project a focused light beam having a numerical aperture of 0.36.

Here, the thickness of the transparent substrate is 0.4 to 0.
When an optical disc with a thickness within the range of 8 mm is used,
The aperture 354 is preferably selected to project a converging light beam having a numerical aperture selected from the range of numerical aperture 0.5 to 0.65, and the thickness of the transparent substrate is 0.9. When an optical disc with a thickness within the range of ~ 1.3 mm is used, the aperture is formed so that a converging light beam having a numerical aperture selected from the range of the numerical aperture 0.3-0.5 is projected. It is preferable that 359 is selected.

It goes without saying that the optical system is not limited to the above-mentioned form and various forms can be adopted.

Various embodiments are possible as means for changing or switching the numerical aperture. For example, a plurality of lenses may be prepared and mechanically selected and switched.
Alternatively, a plurality of pickup units in which a lens and a light beam generation source are integrated may be prepared, and these units may be switched and used. Furthermore,
A single lens may be used to switch a plurality of laser generation sources having different wavelengths.

FIG. 19 shows a summary of the reproducing apparatus of the present invention. The output of the pickup 403 whose reading characteristics can be changed or switched according to the type of the optical disc 401 is input to a signal (data) processing system 404. In this signal (data) processing system 404, 8-14
It includes a demodulation circuit that handles a modulation signal (CD), an 8-16 modulation signal (DVD), etc., demodulates the input signal according to the input, and corrects the error. It also includes a separation circuit for separating the data stream and a decoder for decoding the separated data.

The reproduction signal from the pickup 403 is used by the servo system 405, as described above. Tracking and focus control signals from the servo system 405 are fed back to the pickup 403. A speed control signal for controlling the rotation of the optical disc 401 is also fed back from the servo system 405 to the pickup motor 402. The system control unit 406 can switch the characteristics of the signal (data) processing system 404 and the processing content according to the switching of the numerical aperture. Also, the response characteristic of the servo system 405 can be switched. As the type of the pickup 403, various forms are possible, and it is sufficient that a type suitable for the disc can be selected and the characteristics can be switched. Further, a type in which a plurality of laser beams are used as a light source or a type in which a single laser beam is used may be used. A single lens system may be used or a plurality of lens systems may be used by switching.

That is, this system is an optical disc reproducing apparatus for reproducing a signal recorded on a disc from a plurality of discs having different track pitches through an optical pickup. Then, it has a numerical aperture changing means for changing the numerical aperture of the beam emitted from the optical pickup according to the disc to be reproduced, and also according to the change of the numerical aperture of the beam by the numerical aperture changing means, A signal processing system changing means for changing the characteristics of the signal processing system connected to the subsequent stage of the pickup according to the disc to be reproduced is provided.

Further, this system is a data processing which switches the characteristics of the data processing system connected to the latter stage of the pickup in accordance with the change of the numerical aperture of the beam by the numerical aperture changing means according to the recording format of the disc to be reproduced. It may have a system switching means. In addition, this system switches the characteristics of the data processing system connected to the latter stage of the pickup in accordance with the change in the numerical aperture of the beam by the numerical aperture changing means according to the recording format of the disc to be reproduced. It may be provided with a means. These switching means may be realized by software provided in the system control unit 406, or dedicated hardware may be constructed.

As described above, according to the present invention, the signal processing function is switched in accordance with the switching of the optical system,
Obtain an appropriate pickup, playback and control system suitable for the disc.

Furthermore, the present invention can be effectively incorporated into a reproducing apparatus for reproducing an optical disc having a plurality of layers. For example, it can be effectively utilized not only for disc discrimination but also for switching the state of the reproducing apparatus.

For example, depending on the reproducing apparatus, when there is an operation input from the outside or when the reproduction of one program or one side of the disc is completed, the state switching mode may be automatically entered. In the state switching mode, for example, a compulsory focus adjustment operation is executed. Then, the signal recording surface of another layer is searched. In such a case, the S-shaped signal detecting means described above is effectively used. The waveform of the S-shaped signal reaches a predetermined level at the time of just focus as shown in FIG. Therefore, by providing a control program that forcibly drives the focus adjustment mechanism and switches the processing characteristics of the signal processing unit each time a predetermined value of the S-shaped waveform detection signal is obtained from the S-shaped signal detecting means, The signal processing state corresponding to the recording format of the disc to be reproduced can be obtained.

Various methods can be used to confirm whether the signal processing state is appropriate. For example, in an error correction circuit that processes a reproduction signal, it is determined that an appropriate signal processing state is obtained when the error rate is small. Alternatively, it is also possible to determine the suitability state of the signal processing path depending on whether or not a suitable level is obtained in the middle of the signal processing path.

As an appropriate signal processing state, for example, MP
The operation is such that the processing state of EG-1 is switched to the processing state of MPEG-2. In other words, for a disc of a plurality of laminated types, the first layer is MPEG-
This is because MPEG-2 video compressed data may be recorded in the first and second layers. Video information may be recorded in one layer, and audio information and subtitle information may be recorded in the other layer. In this way, various information may be recorded in combination.

20 (A), 20 (B), 20
20C and FIG. 20D show examples of composite disks 501 and 601 in which two disks each having a thickness of 0.6 mm are laminated.

In the composite disc 501, a signal of the MPEG-1 standard is recorded in the first layer (or the second layer) and a signal of the MPEG-2 standard is recorded in the second layer (or the first layer). Is recorded. When such a composite disc is reproduced, the reproducing apparatus of the present invention has a function of switching the signal processing circuit when the layer of the signal recording surface is detected. Disc discrimination is performed at the start of the first reproduction.
Also in this disc discriminating operation, the layer surface detection function which is the boundary between layers is effectively utilized. This layer surface detection function will be described later.

Next, after the reproduction of the signal of, for example, the first layer of the disc 501 is completed, the focus control is forcibly executed to move to the reproduction of the signal of the second layer. During the focus control, if it is detected that there is a layer surface, the signal processing circuit is automatically switched.

In the composite disc 601, for example, the first layer is a DVD and the second layer is a CD. That is, the first track having a high recording density is formed in the first layer. Further, a second track having a recording density lower than that of the first track is formed on the second layer. The track pitches of the first and second tracks are different.

Even when this composite disc 601 is reproduced, in the reproducing apparatus of the present invention, the same switching of the signal processing circuit as described above is executed. That is, when the signal reproduction of the second layer is continuously executed after the signal reproduction of the first layer, the focus control is forcibly executed. When the second layer is detected during the focus control, the signal processing circuits are automatically switched.
In this case, the signal processing circuit is switched to the CD signal processing circuit.

FIG. 21 shows an example of the structure of the disc reproducing apparatus of the present invention.

The rotation of the optical disc 511 is controlled by the disc motor 12. The pickup device 21 optically reads the recording signal of the optical disc 511. The output signal of the pickup device 21 is amplified by the preamplifier 23. The output of the preamplifier 23 is the data processor 52.
0 and the servo processor 530. The data processor 520 executes demodulation processing, error correction processing, and the like. Information such as video and audio processed by the data processor 520 is stored in the MPEG2 processor 521, MPEG
It is supplied to the 1-processor 522. MPEG2 processor 52
1. The MPEG1 processor 522 performs composite processing of video information and composite processing of audio information. MPEG2
The video information combined by the processor 521 and the MPEG1 processor 522 is input to the video processor 524. The video processor 524 performs gain control on the video signal, color adjustment on the color signal, image quality adjustment on the luminance signal, and the like. The signal from the video processor 524 is NTS.
It is supplied to the C encoder 526 and converted into an NTSC format video signal.

In addition, the MPEG2 processor 521, the MPEG
The audio information combined by the 1-processor 522 is input to the digital audio signal processor 523. The audio signal that has been subjected to gain adjustment or separation processing here is supplied to the next digital-analog converter (not shown).

The above reproducing apparatus can also reproduce CD information. The audio information recorded on the CD is
Servo processor 530 separated by data processor 520
It is demodulated by the CD information demodulator inside. And demodulated C
The D signal is supplied to the digital audio processor 523.

The servo processor 530 uses the high frequency signal from the preamplifier 23 to generate various control signals. For example, it is a focus control signal of the pickup device 21, a tracking control signal, a control signal for the disc motor 12, and the like.

According to the reproducing apparatus described above, FIG.
The optical discs shown in FIGS. 20A and 20B can be reproduced, and FIGS. 20C and 20D.
The optical disc shown in can also be played.

In the above-mentioned reproducing apparatus, the disc discriminating function operates when the disc is mounted. When the disc discrimination function operates, the focus control unit is forcibly driven. When the focus control unit is forcibly driven, a plurality of S-shaped signals are obtained from the S-shaped level detector 26B (see FIG. 11) included inside the data processing unit 520. That is, an S-shaped signal is obtained each time the focal point of the light beam passes the layer surface of the disc.

FIG. 22A shows an S-shaped signal obtained when, for example, the disc 501 of FIG. 20A is mounted in the reproducing apparatus and the focus control section is forcibly operated. When the lens gradually approaches the disc from a position away from the disc, the beam spot will pass through the two signal recording surfaces. With this disc 501, the two signal recording surfaces are close to each other.

Here, the disc type is determined by measuring the time T1 from the time t1 when the beam spot passes the first signal recording surface to the time t2 when the beam spot passes the second signal recording surface. be able to.

FIG. 22B shows an S-shaped signal obtained when, for example, the disc 601 of FIG. 20C is mounted on the reproducing apparatus and the focus control section is forcibly operated. In this case also, the beam spot will pass through the two signal recording surfaces. With this disc 601, the distance between the two signal recording surfaces is
Is larger than the distance between the two signal recording surfaces.

Therefore, the type of the disc can be determined by measuring the time T2 from the time t1 when the beam spot passes the first signal recording surface to the time t3 when the beam spot passes the second signal recording surface. You can

The S-shaped signal is also detected when the beam spot passes through the surface of the disc (different from the signal recording surface). However, since the S-shaped detection signal at this time has a low level, it is removed by the noise removal filter 26A (see FIG. 11).

FIG. 23 shows an algorithm of a function of detecting the layer thickness of the disc and discriminating the disc type. When the disc is mounted on the reproducing device, the actuator of the focus adjusting device is forcibly driven.
That is, the focus control is forcibly executed (steps J1 and J2). In the middle of this focus control, it is determined whether or not an S-shaped signal is obtained (step J
3). When the S-shaped signal is detected, it is judged whether or not this is the first detection (J4). If it is the first detection, the counting operation of the counter is started (step J5). Then, from the time when the focus control is started, it is judged whether or not the predetermined time is exceeded (step J6). If the current time is within a predetermined time, focus control is continued.

If the time is exceeded while the judgments of steps J2 to J6 are continued, it is judged that the target disk has one signal recording surface.

During the focus control, it is determined whether or not the S-shaped signal is obtained (step J3). When the S-shaped signal is detected, it is judged whether or not this is the second detection (J7). If it is the second detection, the first count value of the counter is stored (step J
8). Then, the counter is restarted (step J9). Next, it is determined whether or not the time is over a predetermined time (step J6), and if the current time is within the predetermined time, the focus control is continued. If the present time has passed a predetermined time, the disc type is determined using the count value. That is, the distance between the first and second signal recording surfaces is determined based on the count value. At this point, the discs 501 and 601 can be discriminated.

This system is designed so that discs with more layers can be discriminated. That is, during the focus control, it is determined whether the S-shaped signal is obtained (step J3). When the S-shaped signal is detected, it is judged whether or not this is the third detection (J10). If it is the third detection, the second counter
Is stored (step J11). Then, the counter is restarted (step J9) and the process returns to step J2. Up to this point, the disc has been found to have three signal recording surfaces.

Further, during the focus control, it is judged whether or not the S-shaped signal is obtained (step J).
3). When the S-shaped signal is detected, it is judged whether or not this is the fourth detection (J10). If it is the fourth detection, the third count value of the counter is stored (step J11). Then, the counter is restarted (step J9) and the process returns to step J2.

When the S-shaped signal is not detected, it is constantly monitored whether or not the time is over. When the time is over, the count value is used to determine how many layers are on the recording surface of the disc. Moreover, the thickness of each layer of the disc can be determined by using the count value (steps J13, J14, J15). This thickness information may be used as reference data when the focus control is performed by the pickup device. For example, when the beam spot is aligned with the data recording surface of the second layer after the reproduction of the data of the first layer of the two-layer disc is completed,
The thickness information may be used in the focus control unit. That is, when performing focus adjustment, this thickness information can be used as control information for driving the actuator. However, in this case, since the moving speed of the actuator varies depending on the magnitude of the coil current that drives the actuator, the thickness information may be finely corrected and used. When the coil current for driving the actuator is different between when the disc is discriminated and when the actual data is reproduced, the thickness information is finely corrected and used.

In the above description, the time when the counter starts counting is from the time when the first signal recording surface is detected. However, the time when the actuator is driven, that is, counting from step J2. May start. With this counting method, the disc shown in FIG. 1B and the disc shown in FIG. 1C can be distinguished from each other according to the count number when the first signal recording surface is detected.

FIG. 24A shows a CD reproducing device. The optical disc 601 (see FIG. 24B) is
It is rotationally driven by the disk motor 610. The recording signal of the optical disc 601 is read by the pickup device 611. The high frequency signal output from the pickup device 611 is amplified by the preamplifier 612. The output of the preamplifier 612 is input to the servo processor 618 and the CD interface 613. For the CD interface 613, for example, 8/1
4 conversion (EFM) is performed, and the modulated signal is demodulated. This demodulated signal is MPEG1 as a decoder.
It is input to the processor 614. Here, demodulation of a video signal and demodulation of an audio signal are executed. The demodulated video signal is input to, for example, the NTSC encoder 615, and the demodulated audio signal is input to the audio digital-analog converter 616.

The above CD player is designed so that the focus adjustment range of the pickup device 611 is compatible with the conventional CD. However, the disc according to the present invention shown in FIG. 20C has a substrate thickness conforming to the CD standard and a signal recording surface. To this end, FIG.
The disc indicated by 0 (C) can be mounted on a conventional CD player to reproduce the signal recorded in the second layer. That is, the beam emitted from the pickup of the CD player is designed to fit the signal recording layer provided on the disc having a thickness of 1.2 mm. Therefore, the focus of the beam easily coincides with the recording surface of the second layer.

[0148]

According to the present invention described above, the signal and data processing circuit is switched to a state adapted to the disc according to the type of the disc.

[Brief description of drawings]

FIG. 1 is a view showing in principle the cross section of each type of optical disc.

FIG. 2 is an enlarged view of the recording surface of various optical discs and is shown from the back side.

FIG. 3 is a diagram showing an example of a reproducing apparatus using the present invention.

FIG. 4 is a diagram showing characteristics of a focus error signal.

FIG. 5 is a diagram showing in detail the inside of a photodetector and a preamplifier of the optical pickup device.

FIG. 6 is a diagram showing an example of an identification signal of a recordable optical disc.

FIG. 7 is a flowchart showing an example of disc discrimination processing according to the present invention.

FIG. 8 is a flowchart showing another example of the disc discrimination processing according to the present invention.

FIG. 9 is a flowchart showing still another example of the disc discrimination processing according to the present invention.

FIG. 10 is a flowchart showing still another example of the disc discrimination processing according to the present invention.

FIG. 11 is a diagram showing another example of a reproducing apparatus using the present invention.

FIG. 12 is a flowchart showing another example of the disc discrimination processing according to the present invention.

FIG. 13 is a flowchart showing still another example of the disc discrimination processing according to the present invention.

FIG. 14 is a flowchart showing still another example of the disc discrimination processing according to the present invention.

FIG. 15 is a flowchart showing another example of the disc discrimination processing according to the present invention.

FIG. 16 is a diagram showing an example of an optical system of a reproducing apparatus according to the present invention.

FIG. 17 is a diagram showing an example of an optical system of a reproducing apparatus according to the present invention.

FIG. 18 is a diagram showing an example of an optical system switching means of the reproducing apparatus according to the present invention.

FIG. 19 is a diagram showing an example of the overall block configuration of a reproducing apparatus according to the present invention.

FIG. 20 is a view showing an example of an optical disc relating to the present invention and a principle sectional view of the disc.

FIG. 21 is a diagram showing another embodiment of the reproducing apparatus according to the present invention.

FIG. 22 is a diagram showing an example of an s-shaped signal obtained when the reproducing apparatus of the present invention discriminates a disc.

FIG. 23 is a diagram showing an example of a flowchart when the reproducing apparatus of FIG. 22 makes disc determination.

FIG. 24 is an explanatory diagram of a case where an optical disc according to the present invention is played back by a playback device dedicated to a CD.

[Explanation of symbols]

 11 ... Optical disc 12 ... Disc motor 21 ... Pickup device 22 ... Feed motor 23 ... Preamplifier 24 ... Equalizer 25 ... DVD / CD signal processing unit 26A ... Filter 26B ... S-curve level detector 27, 33 ... Compensation amplifier 32 ... Switch 100 ... System control unit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location G11B 20/18 501 G11B 20/18 501D 572 572F

Claims (53)

[Claims] 1. An optical disc reproducing apparatus capable of reproducing signals recorded on a plurality of types of discs via a pickup, and the signals are emitted from the pickup corresponding to the disc to be reproduced. Numerical aperture changing means for changing the numerical aperture for the beam, and in accordance with the change of the numerical aperture by the numerical aperture changing means,
An optical disc reproducing apparatus comprising: a signal processing system changing means for changing the characteristics of a signal processing system connected to the latter stage of the pickup to a state corresponding to the disc to be reproduced. 2. An optical disc reproducing apparatus capable of reproducing signals recorded on a plurality of types of discs via a pickup, and the signals are emitted from the pickup corresponding to the disc to be reproduced. A numerical aperture changing means for changing the numerical aperture for the beam; and a characteristic of a signal processing system connected to the latter stage of the pickup in association with the change of the numerical aperture by the numerical aperture changing means. An optical disc reproducing apparatus comprising: a signal processing system changing means for changing to a state corresponding to a disc. 3. An optical disc reproducing apparatus capable of reproducing data recorded on a plurality of types of discs having different recording formats from each other via a pickup, in accordance with the disc to be reproduced, Numerical aperture changing means for changing the numerical aperture for the beam emitted from the pickup, and in accordance with the change of the numerical aperture by the numerical aperture changing means,
An optical disc reproducing apparatus comprising a data processing system switching means for switching the characteristics of a data processing system connected to the latter stage of the pickup to a state corresponding to the recording format of the disc to be reproduced. 4. An optical disc reproducing apparatus capable of reproducing data recorded on a plurality of types of discs having different recording formats from each other via a pickup, in accordance with the disc to be reproduced, The numerical aperture changing means for changing the numerical aperture for the beam emitted from the pickup, and the characteristic of the data processing system connected to the latter stage of the pickup in association with the change of the numerical aperture by the numerical aperture changing means. And a data processing system switching means for switching to a state corresponding to the recording format of the disc to be reproduced. 5. An optical pickup device equipped with a plurality of optical systems having different beam spot sizes or different wavelengths and a switching means for facing one of the plurality of optical systems to an optical disc. A signal processing unit for processing a signal from the optical pickup device, wherein any one of a plurality of signal processing characteristics can be set according to the type of the optical disc. When one of the plurality of optical systems of the pickup device and one of the plurality of signal processing characteristics of the signal processing unit are set, the relationship of the other is set. And a control section for selectively setting the optical system or the signal processing characteristic in an active state. 6. The plurality of optical systems are sub-beam / main-beam type optical systems, including 3-beam type and 1-beam type optical systems, and when a disc having a first track pitch is reproduced. Is the three-beam type optical system,
6. The control unit is controlled to switch to the one-beam type optical system when a disc having a second track pitch smaller than the first size track pitch is reproduced. The optical disc reproducing apparatus described above. 7. The optical signal processing apparatus according to claim 1, wherein the signal processing system is a reproduction signal processing unit that demodulates and reproduces a recording signal of the optical disc using a signal from the pickup device. Disc playback device. 8. The signal processing system performs focus control of an optical system of the pickup device by using a signal from the pickup device, and is a focus servo system whose characteristics can be switched. Item 1. An optical disc reproducing apparatus according to Item 1. 9. The signal processing system performs tracking control of an optical system of the pickup device by using a pickup signal from the pickup device, and is a tracking servo system whose characteristics can be switched. An optical disc reproducing apparatus according to claim 1. 10. A plurality of optical systems having different beam spot sizes or different wavelengths, switching means for switching any one of the plurality of optical systems so as to face a mounted disc, and the disc. An optical pickup device equipped with a detection means for detecting the reflected light of the beam applied to the disc, a focus adjustment mechanism for the disc, and a tracking adjustment mechanism for the disc, and the processing characteristics can be switched according to the type of the disc. The signal detected by the detection means is used to reproduce a signal recorded on the disc, and the characteristics can be switched according to the type of the disc.
Using a signal detected by the detection means, a focus error signal is generated and a focus servo means for feeding back to the focus adjustment mechanism, and characteristics can be switched according to the type of the disc,
A tracking servo unit that generates a tracking error signal using the signal detected by the detection unit and feeds back to the tracking adjustment mechanism; and an optical system that is adapted to a predetermined disc among the plurality of optical systems, An optical system setting unit to be selected by the switching unit, and a process corresponding to the predetermined disk for the signal processing unit, the focus servo unit, and the tracking servo unit when the optical system setting unit selects the arbitrary optical system. An optical disc reproducing apparatus comprising: a system setting unit for switching between a characteristic and a servo characteristic; and a system control unit having the disc type discriminating unit. 11. The system control means is such that the level of a focus determination signal from the detection means is
If the level is smaller than the predetermined level, the optical disc has a plurality of layers, and if the level of the focus determination signal is higher than the predetermined level, it is determined that the disc is a single layer and is for reproduction only. 11. The optical disc reproducing apparatus according to claim 10, further comprising a determining unit. 12. When the discriminating means discriminates that the disc is a single layer and is for reproduction only, focus is set by the focus servo means and a tracking discriminating signal is discriminated. 12. An optical disc reproducing apparatus according to claim 11, further comprising means for obtaining an output in which the type of the disc is discriminated depending on whether the disc is larger or smaller than a predetermined level. 13. When obtaining the tracking determination signal, the means for rotating the disk forcibly turns off the disk rotation servo loop to rotate the disk independently to prevent runaway of the disk rotation. 13. The optical disc reproducing apparatus according to claim 12, wherein: 14. The system control means determines whether the level of the focus determination signal from the detection means is higher or lower than a predetermined level, and the level of the focus determination signal is higher than the predetermined level. 11. The reproducing apparatus for an optical disc according to claim 10, further comprising a determining unit that determines that the disc is a two-layer disc for reproduction only or a single-layer disc for recording if the disc is small. 15. When the determination means determines that the disc is a read-only disc having a plurality of layers or a single-layer disc for recording, focus is set by the focus servo means and a predetermined reproduction signal is set. 15. An optical disc reproducing apparatus according to claim 14, further comprising means for obtaining an output which discriminates the disc depending on whether or not the discriminating signal is included. 16. The system control means is such that the level of a focus determination signal from the detection means is
When there is a determination unit that determines whether the level is higher or lower than a predetermined level and a determination result that the level is lower than the predetermined level is determined by the determination unit, the focus servo unit is forcibly controlled and the focus When the level of the discrimination signal is smaller than the predetermined level, the focus servo means is controlled to gradually bring the selected optical system closer to the disc from a position away from the disc so that the focal plane of the focus signal is changed. 11. The optical disc according to claim 10, further comprising means for determining whether the disc is a plural disc or a single disc, and obtaining an output for discriminating whether the mounted disc is a multi-layer disc or a single-layer disc. Playback device. 17. The system control means forcibly controls the focus servo means, and when the level of the focus determination signal is lower than a predetermined level, controls the focus servo means to select the focus servo means. The optical system is gradually brought closer to the disc from a position far away from the disc to determine whether the focal plane of the focus signal is plural or singular, and the mounted disc is a multi-layer disc or a single-layer disc. 11. The optical disc reproducing apparatus according to claim 10, further comprising means for obtaining a determination output as to whether or not 18. The system control means, when the type discriminating means discriminates a disc type, the disc discriminating means is adapted to the disc type discriminated.
11. The optical disk reproducing apparatus according to claim 10, further comprising means for resetting the signal processing unit, the focus servo means, and the tracking servo means so as to control the system in a reproducible or recordable state. 19. The system control means, when the type discriminating means discriminates a disc type, the disc type discriminated is the same as the disc type designated by the operation input information. 11. The optical disc reproducing apparatus according to claim 10, further comprising means for confirming whether or not it is present and displaying a warning if they are different. 20. The system control means, when the optical system setting means and the system setting means construct a reproduction state corresponding to a designated disc in response to a disc type designation operation from a user. If the error of the reproduction signal in the signal processing unit is larger than a predetermined amount, a warning is displayed and waits for the user to change the designation of the disc type, and if the error is smaller than the predetermined amount. 11. The optical disc reproducing apparatus according to claim 10, further comprising means for executing a reproducing operation. 21. When the system control means constructs a reproduction state corresponding to the designated disc, the means for self-designating the disc type when the disc is set, and the optical system setting means and the system setting means When the error of the reproduction signal of the signal processing unit is larger than a predetermined amount, a warning is displayed, and the self-designating means is instructed to specify another type of disc, and the error is determined to be predetermined. 11. The reproducing apparatus for an optical disc according to claim 10, further comprising means for executing a reproducing operation when the amount is smaller than the amount. 22. A plurality of optical systems having different beam spot sizes or different wavelengths, switching means for facing any one of the plurality of optical systems to a mounted disc, and the disc being irradiated. Detecting means for detecting the reflected light of the beam, an optical pickup device equipped with a focus adjustment mechanism for the disc, and a tracking adjustment mechanism for the disc, and processing characteristics can be switched according to the type of the disc, Using the signal detected by the detection means, it is possible to switch the characteristics depending on the type of the disc and a signal processing unit for reproducing the signal recorded on the disc,
Using the signal detected by the detection means, a focus determination means is generated to generate a focus determination signal and fed back to the focus adjustment mechanism, and characteristics can be switched according to the type of the disc.
Of the plurality of optical systems, a tracking servo unit that generates a tracking determination signal using the signal detected by the detection unit and feeds back to the tracking adjustment mechanism, and a plurality of optical systems according to designated input information of the type of the disc, An optical system setting unit that causes the switching unit to select an arbitrary optical system adapted to an arbitrary disc as an optical system to be used, and the signal processing unit when the optical system setting unit selects the arbitrary optical system. And system setting means for switching the focus servo means and the tracking servo means to the processing characteristics and servo characteristics corresponding to the arbitrary disc, and when the error of the reproduction signal in the signal processing unit is more than a predetermined amount, A disc setting mode switching means for changing the designation of the type, and a re-setting in the signal processing unit. And a means for performing a reproducing operation when the error of the raw signal is smaller than a predetermined amount. 23. The optical disc reproducing apparatus according to claim 22, wherein the disc type designation input information of the optical system setting means is introduced by an operation input from a user. 24. The optical disc according to claim 22, wherein the disc type designation input information of the optical system setting unit is provided from a unit that automatically designates the disc type when the disc is set. Playback device. 25. The disk setting mode switching means for changing the specification of the disk type switches the disk setting mode in an order determined in advance according to the disk type. Optical disc player. 26. The optical disc according to claim 22, wherein the disc setting mode switching means for changing the designation of the disc type cyclically switches the disc setting mode in a predetermined order. Playback device. 27. The disk setting mode switching means for changing the specification of the disk type switches the disk setting mode according to the disk type according to an operation input from the user. Optical disc player. 28. An optical disc reproducing apparatus capable of reproducing signals recorded on a composite disc composed of a plurality of layers via a pickup, wherein an appropriate signal processing system among a plurality of signal processing systems is provided, Any one of the plurality of signal processing systems when the detection signal of the reflected light detecting means provided in the pickup indicates that the layer surface of the disc is detected in order to correspond to each layer of the disc to be reproduced. An optical disc reproducing apparatus equipped with state setting means for setting one of the systems. 29. The optical disc reproducing apparatus according to claim 28, wherein the detection signal of the reflected light detecting means changes in an S-shaped characteristic according to a focus state of a beam emitted from the pickup. . 30. The optical disc reproducing apparatus according to claim 28, wherein the detection signal from the reflected light detecting means is a signal when the focal point of the beam passes through the layer surface of the disc. 31. The pickup includes a plurality of optical systems having different beam spot sizes or different wavelengths,
It has a switching means for acting on a disc on which any one of the plurality of optical systems is mounted, a focus adjustment mechanism for the beam with respect to the disc, and a tracking adjustment mechanism for the beam with respect to the disc. The optical disc reproducing apparatus according to claim 28. 32. The optical disc reproducing apparatus according to claim 31, wherein the state setting means can switch a method of generating a tracking error signal of the pickup. 33. The pickup according to claim 32, characterized in that, as the means for generating the tracking error signal, it has means for generating using a four-division photodetector and means for generating using a sub-photodetector. Optical disc player. 34. The state setting means sets the overall signal processing system by switching the plurality of signal processing systems each time the reflected light detection means detects the layer surface. 29. The optical disc reproducing apparatus according to claim 28. 35. The optical disc reproducing apparatus according to claim 34, wherein the plurality of signal processing systems can process video signals of different compression methods when the signal processing methods are switched. 36. The signal processing system according to claim 34, wherein when the signal processing system of the plurality of signal processing systems is switched, a signal processing system for processing a video signal compressed using frame correlation is switched. Optical disc player. 37. The plurality of signal processing systems are MPEG
35. The optical disc reproducing apparatus according to claim 34, further comprising a signal processing system such as 1, MPEG2 or the like. 38. The plurality of signal processing systems are MPEG
35. The optical disc reproducing apparatus according to claim 34, further comprising a signal processing system for 1, MPEG2, etc. and a CD. 39. The optical disc reproducing apparatus according to claim 34, wherein the set signal processing system is a system corresponding to a signal recording format of a layer to be reproduced of the disc. 40. The plurality of optical systems include a three-beam system using a sub-beam and a main beam, and a one-beam system using the main beam, the first optical system of the disc.
3. The optical system of the 1-beam system is switched when the signal of the layer is reproduced, and the optical system of the 3-beam system is switched when the signal of the second layer is reproduced.
8. An optical disc reproducing apparatus according to item 8. 41. The positional relationship between the optical system and the first and second layers is such that the first layer is closer to the optical system,
41. The optical disc reproducing apparatus according to claim 40, wherein the second layer is farther from the optical system. 42. The positional relationship between the optical system and the first and second layers is such that the second layer is closer to the optical system,
41. The optical disc reproducing apparatus according to claim 40, wherein the first layer is separated from the optical system. 43. The optical disc reproducing apparatus according to claim 40, wherein the plurality of optical systems are optical systems of a type in which focal lengths are switched by switching lenses. 44. The optical disc apparatus according to claim 40, wherein the plurality of optical systems are optical systems of a type in which light sources having different wavelengths are switched without switching lenses. 45. The optical disc reproducing apparatus according to claim 28, wherein the state setting means also switches and sets the characteristics of the focus and tracking control loop of the pickup. 46. The positional relationship between the first layer and the second layer of the disc and the pickup is such that the side closer to the pickup is the first layer and the side farther from the pickup is the second layer. The means is arranged to DV the signal processing system when the beam of the pickup is focused on the first layer.
29. The optical disc reproducing apparatus according to claim 28, wherein when the D processing mode is set and the second layer is focused, the signal processing system is set to the CD processing mode. 47. An optical pickup device equipped with a plurality of optical systems having different beam spot sizes or different wavelengths, and a switching means for facing any one of the plurality of optical systems to an optical disc. According to the layer of the optical disc, it is possible to set any one of a plurality of signal processing characteristics,
A signal processing unit for processing a signal from the optical pickup device; any one optical system of the plurality of optical systems of the optical pickup device; and a plurality of signal processing characteristics of the signal processing unit. An optical disc reproducing apparatus, comprising: a control unit for selectively setting one of the signal processing characteristics of one of them to an active state of the other related optical system or signal processing characteristic. . 48. An apparatus for reproducing a disc having a plurality of layers, comprising: a plurality of optical systems having different wavelengths; and a layer surface of an arbitrary layer of a disc on which any one of the plurality of optical systems is mounted. Switching means for switching to act on the layer surface of the disc, detection means for detecting the reflected light of the beam irradiated on the layer surface of the disc, a focus adjusting mechanism for the layer surface of the layer, and tracking for the recording track of the disc. An optical pickup device equipped with an adjusting mechanism, and processing characteristics can be switched according to a recording signal on the layer surface of the layer, and a signal recorded on the disc is detected by using a signal detected by the detecting means. The characteristics can be switched according to the signal processing unit for reproducing and the recording signal on the layer surface of the layer, and the focus error is detected by using the signal detected by the detection unit. A characteristic can be switched according to a focus servo unit that generates a signal and feeds it back to the focus adjustment mechanism, and a recording signal on the layer surface of the layer, and a tracking error signal is generated by using the signal detected by the detection unit. A tracking servo unit that generates and feeds back to the tracking adjustment mechanism, and an optical system that causes the switching unit to select an arbitrary optical system that adapts a recording signal of a predetermined layer surface of the layer among the plurality of optical systems. When the setting unit and the optical system setting unit select the arbitrary optical system, the signal processing unit, the focus servo unit, and the tracking servo unit have processing characteristics and servo characteristics corresponding to the recording signal of the layer. A system setting means for switching and a system control means having a discrimination means for the layers are provided. Reproducing apparatus of an optical disk according to claim. 49. An optical disc, wherein signals of different systems are recorded on the signal recording surfaces of the first layer and the second layer. 50. The optical disc according to claim 49, wherein signals of MPEG2 and MPEG1 standards are recorded on the signal recording surfaces of the first and second layers. 51. A track having a first recording density is formed on the first layer, and a track having a second recording density lower than the first recording density is formed on the second layer. 50. The optical disc of claim 49, wherein the optical disc is a disc. 52. The track of the first recording density of the first layer is substantially aligned with the aiming point of the first beam emitted from the pickup of the first disc reproducing device,
50. The track of the second recording density of the second layer is manufactured so as to be substantially aligned with the aiming point of the second beam emitted from the pickup of the second disc reproducing apparatus. Optical disc. 53. The track of the first recording density of the first layer has a depth of approximately 0.6 mm from a predetermined layer surface, and the track of the second recording density of the second layer comprises: 52. The optical disc of claim 51, wherein the depth is approximately 1.2 mm from the surface of the predetermined layer.