JPH1021553A - Information reproducing device and information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the reproduction with one reproducing device by making the information of both tracks on the land and groove optionally reproducible. SOLUTION: When the output of a recording medium judging circuit 66 is inputted to a control circuit 24 and an inserted recording medium is recognized as the land/groove recording medium, a focus actuator 13 of an optical head is driven to perform the focus setting control to the optional track on the medium. The setting control is made in such a manner that a switch circuit 18 is made to the closed state to output a focusing signal to the actuator 13, thereby, a light spot is focused on the track surface. During the setting control, a tracking servo loop is made to the opened state by opening a switch 17. When the focusing is accomplished, the switch 17 is made to the closed state by the circuit 24 to output the output signal of a circuit 54 of forcedly driving a tracking actuator to the tracking actuator 11, then the actuator 11 is operated by an output signal of the circuit 54. Thus, the optional track is reproduced by one reproducing device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information reproducing apparatus for reproducing information recorded on an information recording medium such as an optical disk, and an information recording medium for recording information.

[0002]

2. Description of the Related Art As an example of a conventional information reproducing apparatus, there is a reproducing apparatus for a compact disk (CD). FIG.
FIG. 3 is a diagram showing a configuration of D. As shown in FIG.
Has a relief-shaped phase pit row 82 spirally formed on a transparent substrate 81 having a thickness of 1.2 mm. This is the information track. The audio information is recorded by associating the audio information with the length of the phase pit.

When reproducing information recorded on a CD, first, the CD is rotated. Then, a light spot having a radius slightly larger than the phase pit is formed on the information track by the light beam emitted from the reproducing head.
Then, information is reproduced by detecting the diffraction state of the reflected light of the light spot irradiated on the information track.

When there is no phase pit at the position of the light spot, all the reflected light from the information track returns to the reproducing head. Therefore, the information detector built into the playback head
Detect large values. If there is a phase pit at the position of the light spot, the reflected light from the information track is diffracted by the phase pit. Therefore, a part of the reflected light is reflected outside the reproducing head and does not return to the reproducing head. The remaining part of the reflected light returns to the reproducing head. That is, when there is a phase pit at the position of the light spot, the information detector built in the reproducing head detects a small value.

Generally, the radius of a light beam from a reproducing head can be reduced to the diffraction limit. Therefore, if an information reproducing head having a built-in laser light source having a wavelength of 830 nm is used, the radius of a light spot applied to an information track can be reduced to 1 μm or less. Therefore, the pitch of the information tracks can be 1.6 μm, and a large amount of information can be recorded.

Examples of other information reproducing devices include a magneto-optical disk device and a phase change disk device. The playback principle of these devices is the same as that of the CD playback device except that the Kerr rotation effect and the reflectance change effect of the reflected light from the medium are used, and therefore detailed description is omitted.

[0007]

However, the potential demand for recording more information on the information recording medium is extremely high. The inventor has made many studies to meet this demand. In general, it has been proposed to reduce the reproducing beam diameter by shortening the wavelength of the light source of the reproducing head and to reduce the track pitch.

However, the wavelength of the light source of the reproducing head is limited, and it is impossible to reduce the wavelength indefinitely.
On the other hand, if the size of the reproduction beam is fixed and the track is narrowed, a light spot by the reproduction beam is also irradiated on the information pit of the adjacent track. As a result, there arises a problem that information of an adjacent track is read in addition to information other than the target reproduction track.

Therefore, there is a need for an information reproducing apparatus capable of suppressing information reading from an adjacent track and reproducing only information from a target track. As a result of many studies, a land / groove reproduction method has been found as a measure for suppressing such information reading from an adjacent track. Generally, tracks on a recording medium such as a magneto-optical disk are
It is formed by concentric or spiral grooves.
Therefore, a convex portion and a concave portion exist on the recording surface. In a conventional recording medium, either one of a convex portion and a concave portion is information. On the other hand, in the land / groove reproduction method,
A disc in which information is recorded on both the convex portions (lands) and the concave portions (grooves) is used.

This method is an extremely excellent method in which the track pitch can be reduced to about half. The effect of suppressing information reading from adjacent tracks by the land / groove reproduction method has been described in the following literature, and therefore detailed description is omitted here. The technology related to phase change disks
It is described in "High Density Phase Change Disk by Land & Groove Recording (5th Phase Change Recording Research Group Symposium Proceedings)". The technology related to magneto-optical disks is described in "CROSSTALK ANALYSIS OF LAND / GROOVE MAGNE
TO-OPTICAL RECODING (SYMPOSIUM ON OPTICAL MEMORY 19
94) ".

[0011] Also, Japanese Patent Application No. Hei 6-90695, Japanese Patent Application No. Hei 6-215137
And Japanese Patent Application No. 6-215138 (both filed by the present applicant) also describe the effect of suppressing information reading from adjacent tracks in the land / groove reproducing method. However, in the land / groove reproduction method, since there are two types of information tracks, a land track and a groove track, information of an arbitrary track cannot be freely reproduced by the conventional technique.

For example, when reproducing information from a recording medium, the information recorded on the information track is sequentially reproduced by moving the light spot relatively on the information track. Specifically, in the reproduction of a CD, the irradiation position of the light spot is controlled while the disc is rotated, so that the light spot is always on the information track. Such control is called tracking control.

[0013] The tracking control mechanism in the conventional device can cope only with tracking of either the land track or the groove track. This is because the tracking characteristics are different between the land track and the groove track, so that if the tracking control is performed in accordance with the characteristics of one track, it is not suitable for the tracking control of the other track.

As described above, since the control method such as tracking control is different, a recording medium for land / groove recording and a recording medium on which information is recorded on one of the land / groove are used.
It is conceivable that it will be difficult to play back with one playback device. The present invention has been made in consideration of the above problems, and provides an information reproducing apparatus capable of arbitrarily reproducing information on both land and groove tracks, and an information recording medium used therefor. With the goal.

[0015]

Means for Solving the Problems To solve the above problems,
According to the present invention, the first group of information tracks and the second group of information tracks on which information is recorded are present concentrically or spirally, and the first group of tracks and the second group of tracks are arranged in a radial direction. The information is recorded only on the first information recording medium housed in the case having the first shape and the information is recorded only on one of the first group and the second group. An information reproducing apparatus capable of reproducing with respect to a second information recording medium housed in a case having a shape, wherein the case of the inserted information recording medium has the first shape or the second shape. Identifying means for identifying whether the shape is a shape, and when the identifying means determines that the shape is the first shape, a reproducing operation suitable for the first information recording medium is performed, and If so, Serial and a configuration in which a control means for performing a reproduction operation adapted to the second information recording medium.

[0016] The control means is configured to make the irradiation position of the laser light follow the track of the first group or the track of the second group, and the discriminating means determines that the laser beam has the first shape. If the light beam is irradiated by the track,
Setting means for setting a control condition of the tracking control means to a condition of tracking control for the first group of tracks or a condition of tracking control for the second group of tracks may be adopted.

The setting of the tracking control condition by the setting means may be a setting for switching the polarity of a track error signal used in the tracking control. Further, according to the present invention, the information track of the first group and the information track of the second group on which information is recorded exist concentrically or spirally, and the track of the first group and the track of the second group have a radius. An information recording medium which is provided with steps alternately in the direction and is housed in a case, in which information is recorded on both the first group of information tracks and the second group of information tracks. An identifier indicating that the medium is an information recording medium is provided.

[0018]

FIG. 2 is a diagram showing a track structure of an information recording medium used in an information reproducing apparatus according to one embodiment of the present invention. FIG. 2 shows a configuration of a recording track of a disk-shaped recording medium. The disc-shaped recording medium 1 has a land track 2 and a groove track 3, and the level difference between them is approximately 1 / 7λ. Note that λ is
It is the wavelength of the light beam that illuminates these tracks for playback.

Each track has a phase pit 41
Area where information is recorded by the optical pit 4
2, there is an area where information is recorded. Address information is recorded in an area where information is recorded by the phase pits 41, and information to be recorded (information used by a user) is recorded in an area where information is recorded by the magneto-optical pits 42. ing.

FIG. 3 is a diagram showing a track shape of an information recording medium used in an information reproducing apparatus according to one embodiment of the present invention. On the recording surface of the disc-shaped recording medium 1, land tracks 2 and groove tracks 3 are alternately arranged in the radial direction. Each track is formed in a spiral shape. That is, an uneven double spiral track is formed. The land tracks and the groove tracks may be formed concentrically and formed alternately in the radial direction.

In the case of a spiral track, a land track 2
And the groove track 3 are each formed as one continuous track from the outermost circumference to the outermost circumference, but one round of the track is regarded as one track. FIG.
As shown in (1), each track is composed of address sections 43 and 45 and information recording sections 44 and 46. A continuous pair of an address section and an information recording section is called a sector (for example, a pair of an address section 43 and an information recording section 44). In the track, a plurality of sectors are continuously arranged in the track direction. In the address sections 43 and 45, address information is recorded by phase pits. The information recording unit 4
4 and 46, information used by the user is recorded by magneto-optical pits.

In the address portion of each sector, a track address and a sector address are recorded. The track addresses are assigned, for example, in ascending order from the innermost track.
The same track address is recorded in each sector of one track (one track). In this embodiment, the land track has an odd track address,
An even track address is recorded in the groove track.

For example, the track address of the innermost track (land track) is "1", and the track address of the next outer track (groove track) is "1".
2 ”, and thereafter,“ 3 ”,“
Track addresses are assigned such as 4 "," 5 ", etc. By assigning addresses to each track in this way, odd addresses become land tracks and even addresses become groove tracks.

The step between the land track and the groove track is set to a value that has the effect of suppressing reading of adjacent tracks. This value is slightly different depending on a CD, a magneto-optical disk, a phase change disk, and the like, but is generally about 1/7 wavelength (about 1/7 of the wavelength of the irradiated light beam). That is, when a transparent substrate having a wavelength of 830 nm of the light beam to be irradiated and an index (refractive index) of 1.5 is used, the step is preferably 80 nm.

The property of the information pit is set to a value that has the effect of suppressing reading of the adjacent track. This value is
D, a magneto-optical disk, a phase change disk, and the like, depending on the type of disk. For example, for a CD, it is preferable to set the phase difference to 1/4 wavelength. For a magneto-optical disk, it is preferable to set the complex Kerr rotation angle {k = 0}. That is,
In the case of a magneto-optical disk, a magnetic pit having a Kerr rotation angle θk = 1 ° and a complex Kerr rotation angle {k = 0} may be set as the information pit.

As shown in FIG. 2, in this embodiment, the land track and the groove track have the same width in the disk radial direction. The track pitch is set so that when a reproduction beam is irradiated to the center of a land track, the reproduction beam does not hit an adjacent land track. In this way, even when the reproduction beam is irradiated to the center of the groove track, the reproduction beam is not irradiated to the adjacent groove track.

At this time, the reproduction beam applied to the land track is applied to the adjacent groove track, and the reproduction beam applied to the groove track is applied to the adjacent land track, but it does not matter. That is, when the wavelength of the irradiated light beam is 830 nm and the numerical aperture NA of the objective lens of the optical head is 0.55, the track pitch from the land track to the adjacent groove track may be 800 nm.

FIG. 8 is a view showing a case (disk cartridge) for storing the recording medium used in the present embodiment. In FIG. 8, a recording medium 1 is provided inside a case 60.
Is stored. When the case is stored in the playback device, the shutter 63 opens, and a part of the recording medium 1 stored therein is exposed. The recorded information is reproduced by irradiating the light beam from the optical head 4 of the reproducing device 1 there.

The case 60 has a notch 61 and a hole 62.
Is provided. The notch and the hole are provided only in a case in which a disc in which information is recorded (or can be recorded) on both the land track and the groove track is built. That is, it is not provided in the case of a conventional disk (for example, a disk on which information is recorded only on a land track, or a disk on which information can be recorded only on a land track).

FIG. 9 is a diagram showing a method for detecting whether or not the inserted recording medium is a land / groove recording medium in the reproducing apparatus. In FIG. 9, a notch detector 64 for detecting the notch 61 is provided in the reproducing apparatus.
And a hole detector 65 for detecting the hole 62. The notch detector 64 is provided with a button, and the button is provided so as to be located at the notch 61 of the case 63 when the recording medium has been inserted. If the case without the notch 61 is inserted, the button is pressed by the side of the case.
When the case with the notch 61 is inserted, the button is not pressed.

Therefore, whether or not the inserted recording medium is a land / groove recording medium can be determined based on whether or not the button of the notch detector 64 has been pressed. The hole detector 65 includes an element that emits light and a light receiving element that receives the light. The hole detector 65 is a case 60
Are inserted so that these elements are located on both sides of the position where the hole 62 of the case 60 is located.

When a case having a hole is inserted, light emitted from the light emitting element reaches the light receiving element through the hole, and a current flows through the light receiving element. If a case where no hole exists is inserted, the emitted light does not reach the light receiving element, and no current flows. Therefore,
If the current value from the light receiving element of the hole detector 65 is detected, it can be determined whether or not the inserted recording medium is a land / groove recording medium.

The recording medium determination circuit 66 includes the notch detector 6
4 and a signal from the hole detector 65 (a signal from the light receiving element) are input, and the inserted medium is
It is determined whether or not the medium is a groove recording medium. Two detectors are not necessarily required, and either one may be used. Further, the notch 61 and the hole 62 provided in the case 60 do not always need to be provided, and either one may be provided.
In that case, the reproducing device may be provided with any one of the detectors.

FIG. 1 is a diagram showing a configuration of an information reproducing apparatus according to one embodiment of the present invention. Disc-shaped recording medium 1
Is, for example, 1 by a spindle motor (not shown).
It is rotating at 800 rpm. The disc-shaped recording medium 1 has a land track 2 and a groove track 3, and the level difference between them is approximately 1 / 7λ (λ is the wavelength of the light beam to be irradiated). On the surface 203 of the substrate 201, a reflective layer made of a metal (such as aluminum) is formed.

Note that, here, a track that is convex when viewed from the direction of light beam irradiation is called a land track, and a track that is concave is called a groove track. The disk-shaped recording medium 1 is a magneto-optical disk. Information is recorded on the land track 2 and the groove track 3 by magnetic pits and phase pits. The protective film 202 covering the recording surface on which information is recorded is made of a polymer material.

The optical head 4 for reproducing information recorded on the recording medium 1 has the following configuration. The light beam emitted from the semiconductor laser 5 in the optical head 4 passes through the beam splitter 7 and is converged by the objective lens 6 to form a light spot on the track surface of the recording medium 1. The light reflected on the track surface passes through the objective lens 6 again, is reflected on the beam splitter 7, and is incident on a detector (photoelectric converter, for example, a photodiode) 8.

The reflected light is converted into an electric signal by the detector 8 and enters the electric circuit 9. The electric circuit 9 processes the electric signal from the detector 8 and outputs a track error signal (TE), a focus error signal (FE), a phase pit signal (PPS), and a magneto-optical signal (MoS). The track error signal TE is a signal indicating a shift amount between a light spot formed on a track of the disk-shaped recording medium 1 and a center line in a radial direction of the track. The focus error signal FE is a signal indicating a shift amount between the position of the convergence point of the light beam and the track surface. The phase pit signal PPS is a reproduction signal of information recorded by the phase pit on the track. The magneto-optical signal MoS is a reproduction signal of information recorded by magnetic pits on a track.

The track error signal TE and the focus error signal FE are input to the servo controller 10 where they are processed, converted into a tracking signal, a positioning signal, and a focus signal and output. The tracking signal is a signal for driving the tracking actuator 11. The tracking signal is a signal having a level corresponding to the level of the track error signal TE (the amount of deviation between the light spot and the center line in the radial direction of the track).
The tracking actuator 11 moves the objective lens 6 in the radial direction of the recording medium 1 by an amount corresponding to the level of the tracking signal. This positions the light spot at the center of the track.

The positioning signal is a signal for driving the positioner 12. The positioner 12 moves the optical head 4 in the radial direction of the recording medium 1 according to the level of the positioning signal. The focus signal is a signal for driving the focus actuator 13. The focus signal is a signal of a level corresponding to the level of the focus error signal FE (the amount of deviation between the position of the light beam convergence point and the track surface). Focus actuator 1
3 moves the objective lens 6 in the direction perpendicular to the recording surface of the recording medium 1 by an amount corresponding to the level of the focus signal. This focuses the light spot on the track surface.

On the other hand, the phase pit signal PPS and the magneto-optical signal MOS are input to the system controller 20. These signals are output to the host computer 30 as information read from the recording medium 1. The system controller 20 communicates with the host computer 30 and, in response to a command from the host computer 30,
The read information is sent to the host computer 30.

Further, the system controller 20 creates a control signal based on the phase pit signal PPS and the magneto-optical signal MOS, and sends the control signal to the servo controller 10. FIG.
2 is a configuration diagram of the servo controller 10 and the system controller 20 of FIG. The servo controller 10
4 includes a land track control circuit 14, a groove track control circuit 15, a focus control circuit 16, switch circuits 17, 18, a positioner control circuit 19, a land / groove identification circuit 50, and a tracking actuator forced drive circuit 54. Further, the system controller 20 includes an address detection circuit 21, an information reproduction circuit 22, and a control circuit 24 shown in FIG.

The track error signal TE is input to the land track control circuit 14 and the groove track control circuit 15. Each control circuit has the same control constant and the opposite polarity of the output signal. The switch circuit 17 includes a land track control circuit 14, a groove track control circuit 1,
5. An output signal from the tracking actuator forced drive circuit 54 is input. Then, one of the three input signals is selectively output based on the signal from the system controller 20 and the signal from the land / groove identification circuit 50. The output signal from the switch circuit 17 is output to the tracking actuator 11 as a tracking signal.

A part of the tracking signal from the switch circuit 17 is output to the positioner 12 as a positioning signal via the positioner control circuit 19. The focus error signal controls the focus actuator via the focus control circuit 16 and the switch circuit 18. The switch circuit 18 is controlled between an open state and a closed state by a signal from the system controller 20. That is, the presence or absence of the output from the switch circuit 18 is controlled.
The signal output from the switch circuit 18 is output to the focus actuator 13 as a focusing signal.

The phase pit signal (PPS) is input to the address detection circuit 21. In the address detection circuit 21,
A signal (address signal) indicating address information is detected from the phase pit signal. The address signal output from the address detection circuit 21 is output to the land / groove determination circuit 23.
Sent to The magneto-optical signal (MoS) is transmitted to the information reproducing circuit 2
2 is input. Then, the magneto-optical signal MoS is converted into reproduction data by the information reproduction circuit 22. The address signal output from the address detection circuit 21 and the reproduction data output from the information reproduction circuit 22 are
Is input to The control circuit 24 controls the switch 17 based on the determination signal. The reproduction data is sent to the host computer 30.

FIG. 5 is a diagram showing changes in the track error signal. FIG. 5A shows a temporal change of a track error signal detected when the optical head 6 is moved in the radial direction from the inner peripheral side to the outer peripheral side. In FIG. 5A, the portion indicated by reference numeral (d) is when the light spot is passing through the land track. The portion indicated by the symbol (e) is when the light spot passes through the boundary between the land track and the groove track. The portion indicated by the symbol (f) is when the light spot is passing through the groove track.

FIG. 5B shows a change in the reflectance. The reflectance is the ratio of the amount of light received by the detector 8 to the amount of light emitted. When the light spot passes through the boundary between the land track and the groove track, the reflectance is lower than when the light spot passes through the land track and when the light spot passes through the groove track.

FIG. 5C shows a waveform of a track error signal when the push-pull method is used for detecting a tracking error. When the light spot passes through the land track, the slope of the change over time of the track error signal level is positive. That is, the level monotonically increases. Further, when the track error signal level is passed over the groove track, the gradient of the change with the passage of time becomes negative.

As can be seen from FIG. 5, the polarity of the tracking error signal is reversed between when the light spot passes through the land track and when it passes through the groove track. The tracking signals output from the land track control circuit 14 and the groove track detection circuit 15 are signals for controlling the tracking actuator so that the level of the tracking error signal becomes zero. Since the polarity of the tracking error signal is reversed between when the light spot is on the land track and when the light spot is on the groove track, if the polarity of the tracking signal is also reversed, the tracking control in each track will be improved. Will be done. Therefore, in this embodiment, the polarity of the output of the land track control circuit 14 and the output of the groove track detection circuit 15 are reversed.

Next, the operation of the information reproducing apparatus of this embodiment will be described. First, a recording medium is inserted into the information reproducing device. The control circuit 24 controls the spindle motor 40
By sending a control signal (shown in FIG. 4), the spindle motor 40 starts rotating, and the recording medium placed on the turntable also rotates. The playback device detects whether the inserted recording medium is a land / groove recording medium. This detection can be performed as described above.

The control circuit 24 receives a signal from the recording medium determination circuit 66. Based on this signal, it is determined whether or not the inserted recording medium is a land / groove recording medium. The operation when the inserted medium is recognized as a land / groove recording medium by the control circuit 24 will be described below.

In the reproducing apparatus, when the recording medium is inserted, the information recording medium is rotated at a predetermined rotation speed by the spindle motor. Next, the reproducing apparatus drives the focus actuator 13 of the optical head 6 to perform focus pull-in control on an arbitrary track on the recording medium. This focus pull-in control is performed by the system controller 2
This is performed when the control circuit 24 in 0 outputs a control signal and the switch circuit 18 is closed. When the switch circuit 18 is closed, a focusing signal is output from the switch circuit 18 to the focus actuator 13. Then, the light spot is focused on the track surface by the operation of the focus actuator 13.

When such focus pull-in control is performed, the switch 17 is opened. That is, the land track control circuit 14, the groove track control circuit 1
5. Prevent any signal from any of the tracking actuator forced drive circuits 54 from being output to the tracking actuator 11. This state is a state in which the tracking servo loop is open (servo off).

When the focus pull-in control is performed and the light beam is focused, the control circuit 24 controls the switch 17 to close to the tracking actuator forced drive circuit 54 side. As a result, a signal from the tracking actuator forced drive circuit 54 is output to the tracking actuator 11, and the tracking actuator 11 operates based on the signal from the tracking actuator forced drive circuit 54.

FIG. 6 is a diagram for explaining a method for identifying whether a track irradiated with a light beam is a land track or a groove track from a change in the polarity of a tracking error signal. FIG. 6B shows an output signal from the actuator compulsory drive circuit 54, which shows a drive current of the tracking actuator 11.

FIG. 6A is a diagram showing a change in the irradiation position of the light beam with time. In this case, since the tracking servo is turned off, the absolute position of the light spot only vibrates in the radial direction based on the output signal from the actuator forced driving circuit 54. However, since the tracks on the disk 1 are eccentric,
, The relative position between the light spot and the track on the disk 1 is shifted in the radial direction. Therefore, FIG.
As shown in (a), the irradiation position of the light beam does not continue to be irradiated on the same track, and gradually shifts to an adjacent track.

FIG. 6C shows a waveform of a track error signal when the push-pull method is used for detecting a tracking error. This waveform is a waveform in which the vibration of the light beam irradiation position due to the driving current shown in FIG. 6B overlaps the sinusoidal waveform generated when the light beam irradiation position crosses the track. Here, FIG.
6A, when the light beam is moving on the land track, and when the driving current shown in FIG. 6B is decreasing, the level of the tracking error signal shown in FIG. It decreases (FIG. 6D). FIG. 6 (a)
In FIG. 6, when the light beam is moving on the groove track and the driving current shown in FIG. 6B is decreasing, the level of the tracking error signal shown in FIG. FIG. 6 (f)). When the light beam is moving on the boundary between the land track and the groove track, the level of the tracking error signal shown in FIG. 6C does not change (FIG. 6E).

As described above, when the light beam is applied to the land track and when the light beam is applied to the groove track, the tracking actuator 11
It can be seen that the polarity of the change in the drive signal and the change in the level of the tracking error signal are reversed. Therefore, from this relationship, it is possible to identify whether the track irradiated with the light beam is a land track or a groove track.

FIG. 7 is a diagram showing a configuration example of the land / groove identification circuit 50. In FIG. 7, the tracking error signal (the signal in FIG. 6C) is a high-pass filter 51.
, And the signal from the actuator forced drive circuit 54 (the signal in FIG. 6B) is input to the high-pass filter 52. Each high-pass filter removes a low-frequency signal unnecessary for identification from the input signal and outputs the signal. Output signals from the high-pass filters 51 and 52 are:
It is input to the phase comparator 53. The phase comparator 53 outputs a signal indicating a positive value when the two input signals are in phase, and outputs a signal indicating a negative value when the two input signals are out of phase.
Therefore, in the present embodiment, the land / groove identification circuit 5
When a signal indicating a positive value from 0 is output, the irradiation position of the light beam is a land track, and when a signal indicating a negative value is output, it is a groove track.

In accordance with the identification signal from the land / groove identification circuit 50 as described above, the switch circuit 17 switches from the actuator forced drive circuit 54 to the land track control circuit 14 or the groove track control circuit 15.
Closed to the side. When a signal indicating a positive value is output from the land / groove identification circuit 50, the signal is closed to the land track control circuit 14 side, and when a signal indicating a negative value is output, the signal is output to the groove track control circuit 15 side. Closed.

As a result, a tracking signal corresponding to the track where the light spot is located is output to the tracking actuator 11, and tracking control is started. The light spot can continue to follow the focused track (land track or groove track). For example, if the identification signal from the land / groove identification circuit 50 indicates a land track, the tracking condition is set to a condition corresponding to the land track. Then, tracking pull-in control is performed on the land track.

This control is performed by connecting the switch circuit 17 to the land track control circuit 14 side. As a result, the switch circuit 17 outputs a tracking signal having a polarity suitable for land track tracking control. This tracking signal is sent to the tracking actuator 11, and the tracking actuator 11 performs tracking pull-in control on the land track, and thereafter, the light spot keeps following the land track.

According to the above operation, the light spot is subjected to tracking control and focus control for a certain land track. Then, the light spot keeps following the land track, and keeps applying focus control to the land track surface. In this way, while the light spot follows the land track, it waits for an instruction from the host computer 30 installed outside the reproducing apparatus. Then, the host computer 30 receives an instruction to read information of a predetermined sector. This instruction is input to the control circuit 24 in the system controller 20. The control circuit 24 determines whether the sector that has received the read instruction exists on a land track or a groove track.

Then, the control circuit 24 obtains a difference between the current head position (current track) and the relative position of the sector (target track) that has received the read instruction. The control circuit 24 opens the tracking servo loop (servo off). This control may be performed by opening the switch circuit 17 so that the tracking signal from the switch circuit 17 is not output.

Next, the control circuit 24 performs control to move the optical head 4 in the direction of the target track by sending a control signal to the positioner control circuit 19. While the optical head 4 is moving, a track error signal as shown in FIG. The counter circuit 25 counts the number of pulses of the track error signal. This count value is input to the control circuit 24. From this count value, the number of tracks traversed by the light spot can be determined. Then, when the optical head 4 has been traversed by the number of tracks to the target track (when the position of the light spot is just above the target track), the movement of the optical head 4 is stopped, and the tracking servo is set to a closed loop (servo ON). The movement of the optical head 4 is stopped by the control circuit 24 sending a control signal to the positioner control circuit 19. The control circuit 24 controls the switch circuit 17 to make the tracking servo a closed loop. At this time, if the target track is a land track, the switching circuit 17 outputs a tracking signal having a polarity suitable for the tracking control of the land track. That is, the switch circuit 17 is connected to the output side from the land track control circuit 14. If the target track is a groove track, a tracking signal having a polarity suitable for the tracking control of the groove track is output. That is, the switch circuit 17 is connected to the output side of the groove track control circuit 15. Now, it is assumed that the target track is a groove track.

The reproducing apparatus reproduces information from the track followed by the light spot by the tracking control, and detects the track address. The control circuit 24 confirms that the detected track address is that of the groove track and that the track in which the sector for which the read instruction has been received exists is present.

If the detected track address is different from the address of the track instructed to read, the control circuit 24 determines the current track and the track (target track) in which the sector instructed to read exists. Find the difference in the relative position of. Then, the above operation is performed again. Then, when the current track address matches the address of the track on which the sector for which the read instruction is present is present, the reproducing apparatus reproduces the information of the sector for which the read instruction is received, and transfers the read information to an external host computer. This operation is performed when the control circuit 24 transfers the reproduction data from the information reproduction circuit 22 to the host computer 30.

Thereafter, the reproducing apparatus waits for an instruction from the host computer again. When the control circuit 24 recognizes that the recording medium inserted in the reproducing apparatus is not a land / groove recording medium, the following operation is performed. In a conventional magneto-optical disk, information is generally recorded only on land tracks. Here, a case where reproduction is performed on a magneto-optical disk on which information is recorded only on land tracks will be described.

In the reproducing apparatus, when the recording medium is inserted, the information recording medium is rotated at a predetermined rotation speed by the spindle motor. Next, the reproducing apparatus drives the focus actuator 13 of the optical head 6 to perform focus pull-in control on an arbitrary track on the recording medium. This focus pull-in control is performed by the system controller 2
This is performed when the control circuit 24 in 0 outputs a control signal and the switch circuit 18 is closed. When the switch circuit 18 is closed, a focusing signal is output from the switch circuit 18 to the focus actuator 13. Then, the light spot is focused on the track surface by the operation of the focus actuator 13.

When such focus pull-in control is performed, the switch 17 is opened. That is, the land track control circuit 14, the groove track control circuit 1
5. Prevent any signal from any of the tracking actuator forced drive circuits 54 from being output to the tracking actuator 11. This state is a state in which the tracking servo loop is open (servo off).

Since tracking control is not applied,
The relative position of the light beam and the track in the radial direction changes.
Whether or not the irradiation position of the light beam irradiates the land track can be determined based on the amount of light reflected from the disk surface of the light beam. In general, the amount of reflected light is larger when a light beam is applied to a land portion than when the light beam is applied to a groove portion. Therefore, the control circuit 24 monitors the amount of reflected light, and when the amount of reflected light increases, connects the switch 17 to the land track control circuit 14 to perform tracking pull-in control on the land track. Thereafter, the light beam can continue to follow the land track. Thereafter, the light beam does not need to follow the groove track, and the switch 17 is kept in either the open state or the state connected to the land track control circuit 14 side.

[0071]

As described above, according to the present invention, both the recording medium in which the information is recorded in both the first group and the second group and the recording medium in which the information is recorded in one of the groups are one unit. It can be played back on a playback device. In addition, the track pitch of the recording medium can be substantially reduced to half the conventional one. Therefore, twice the information can be recorded on the recording medium.

Further, according to the present invention, the tracks of the first group and the tracks of the second group can be arbitrarily reproduced. Therefore, it can be used as a random access type storage device. Also, the head does not need a special configuration,
It does not increase costs. Further, the present invention can be applied not only to a read-only medium such as a CD but also to a rewritable medium.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an information recording medium reproducing device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a track structure of an information recording medium used in the information recording medium reproducing device according to one embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of an information recording medium reproducing device according to an embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a servo controller and a system controller of the information recording medium reproducing device according to the embodiment of the present invention.

FIG. 5 is a diagram showing a change in polarity of a track error signal of the information recording medium reproducing device according to the embodiment of the present invention.

FIG. 6 illustrates a method of identifying whether a track irradiated with a light beam is a land track or a groove track from a change in the polarity of a tracking error signal in the information recording medium reproducing apparatus according to an embodiment of the present invention. FIG.

FIG. 7 is a diagram showing a configuration example of a land / groove identification circuit of the information recording medium reproducing device according to the embodiment of the present invention.

FIG. 8 is a view showing a case (disk cartridge) for storing a recording medium according to an embodiment of the present invention.

FIG. 9 shows a reproduction apparatus according to an embodiment of the present invention.
FIG. 9 is a diagram showing a method for detecting whether or not an inserted recording medium is a land / groove recording medium.

FIG. 10 is a diagram showing a configuration of a conventional CD (compact disk).

[Explanation of symbols]

 1: disk-shaped recording medium (magneto-optical disk), 2: land track, 3: groove track, 4: optical head, 5: light source (semiconductor laser), 6: objective lens, 8: detector, 10: servo controller, 14 : Land track control circuit, 15: groove track control circuit, 16: focus control circuit, 17, 18: switch circuit, 20: system controller, 21: address detection circuit, 22: information reproduction circuit, 24: control circuit, 30: Host computer, 40: spindle motor, 41: phase pit, 42: magneto-optical pit, 43, 45: address section, 44, 46: information recording section, 50: land / groove identification circuit, 54: actuator forced drive circuit, 60 : Case (disk cartridge), 61: Notch, 2: Hole, 63: shutter, 64: notch detector 65: Hall detector, 66: recording medium determination circuit.

Claims (4)

[Claims] An information track of a first group and an information track of a second group on which information is recorded exist concentrically or spirally, and the track of the first group and the information track of the second group are present.
The tracks of the group are present with steps alternately arranged in the radial direction, and information is recorded only on the first information recording medium accommodated in the case of the first shape and only one of the first group or the second group. An information reproducing apparatus capable of reproducing information from a second information recording medium stored in a case having a second shape, wherein the case of the inserted information recording medium has the first shape. Or the second shape. If the first shape is determined by the identification unit, a reproducing operation suitable for the first information recording medium is performed. An information reproducing apparatus comprising: a control unit for performing a reproducing operation suitable for the second information recording medium when it is determined that the information has the second shape. 2. The control means includes: a tracking control means for causing an irradiation position of the laser beam to follow a track of the first group or a track of the second group; and the identification means having the first shape. If determined, the control condition in the tracking control means is set to the condition of the tracking control for the first group of tracks or the condition of the tracking control for the second group of tracks, depending on the track on which the light beam is being irradiated. 2. The information reproducing apparatus according to claim 1, further comprising setting means for performing the setting. 3. The information reproducing apparatus according to claim 1, wherein the setting of the tracking control condition in the setting means is a setting for switching a polarity of a track error signal used in the tracking control. . 4. A first group of information tracks on which information is recorded and a second group of information tracks exist concentrically or spirally, and the first group of tracks and the second group of information tracks are arranged concentrically or spirally.
The tracks of the group are present in an information recording medium housed in a case, wherein the tracks are alternately provided in the radial direction, and the case includes both the information tracks of the first group and the information tracks of the second group. An information recording medium provided with an identifier indicating that the information is an information recording medium on which information is recorded.