JP3774944B2 - Recording / reproducing apparatus and method, and optical disk reproducing apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording / reproducing apparatus and method., And optical disc playback apparatus and methodIn particular, by comparing two wobble signals when the tracking of the track adjacent to the edge of the wobbled groove is detracked to the inner peripheral side and the outer peripheral side, the track is on the inner peripheral side of the edge. Recording / reproducing apparatus and method capable of determining whether it is an outer peripheral side or an outer peripheral side, And optical disc playback apparatus and methodAbout.
[0002]
[Prior art]
In recent years, with the rise of so-called multimedia, large volumes of data such as digital still images and moving images are being handled. Such data is generally stored in a predetermined large-capacity recording medium such as an optical disk, and is played back with random access as necessary.
[0003]
An optical disk is used as the above-mentioned recording medium because it can be randomly accessed, has a higher recording density than a magnetic recording medium such as a floppy disk, and can be rewritten in a magneto-optical disk.
[0004]
Many of such magneto-optical disks have irregularities called grooves and lands in the information recording layer, and modulate a carrier having a predetermined frequency by a cluster number or sector number indicating each position on the recording medium, Corresponding to the modulation signal, the groove shape is previously wobbled (meandering), and the address information is held in the groove (edge) shape.
[0005]
In such a recording medium such as an optical disk or a magneto-optical disk, in order to record a larger amount of data, the recording data has been increased in density. For example, the track pitch is reduced and the track direction is reduced. It is considered to increase the line density by increasing the line density.
[0006]
FIG. 16 shows a configuration example of a disc disclosed by the present applicant in Japanese Patent Application No. 8-67880.
[0007]
In the disk D0 of FIG. 16, a groove G-1 wobbled to hold address information and a groove G-2 not wobbled from the inner wall to the outer periphery are separated from the inner wall toward the outer edge. A continuous spiral is formed. Information is recorded or reproduced on the land L formed between the groove G1 and the groove G-2.
[0008]
FIG. 17 shows a state in which a part of the disk D0 is enlarged. In FIG. 17, the groove G-1 is indicated by a wavy line and the groove G-2 is indicated by a straight line. Since the disk D1 is configured such that the wobbling groove G-1 and the non-wobbing groove G-2 are alternately arranged every round, the wobbling groove G-1 has two tracks. Only the pitch is away. Therefore, crosstalk (interference from the edges of other tracks) that occurs when address information is read from these edges can be suppressed. Further, since a groove G as a heat buffering region exists between two adjacent lands, cross erase can also be suppressed. In this way, a recording medium having a high recording density with a narrow track pitch can be realized.
[0009]
[Problems to be solved by the invention]
By the way, the address information of a predetermined track (land L) is held as the shape of the wobbling groove G-1 existing on the right side or the left side of the track. Therefore, when information is recorded on or reproduced from the disk D0, whether the track is an inner track or an outer track of the groove G-1 (the groove G-1 exists on the right side). Or whether it exists on the left side).
[0010]
This determination is made when three laser beams are used, that is, when a main laser beam for recording or reproducing data and a laser beam for tracking error detection on both sides are used, and reflected light from the laser beams on both sides. Can be performed.
[0011]
For example, the spot P1 of the main laser beam is irradiated so that the center is arranged at the center of the track (land L), and the spots P2 and P3 of the laser beams on both sides perform tracking servo by the DPP method. Irradiate to a position whose phase is shifted by ± 180 degrees with respect to the main laser beam. That is, the laser beams on both sides are irradiated to a position shifted toward the inner circumference side or the outer circumference side of the disk 12 by a width of ½ of the track pitch, that is, to the center of the groove G existing on both sides of the track. The above determination can be made by comparing the wobble signals obtained from the reflected light of the two laser beams on both sides. However, in this method, it is necessary to use three laser beams, and there is a problem that cannot be realized by an optical pickup that emits one laser beam.
[0012]
Therefore, it is conceivable to perform this determination using one laser beam instead of using three laser beams. For example, the above determination is performed by irradiating one laser beam to the position of the spot P1 in FIG. 17 (position on a predetermined track) and comparing the wobble signal from the region A with the wobble signal from the region B. Like that. However, this method has a problem that it is difficult to discriminate due to the aberration of the laser beam.
[0013]
The present invention has been made in view of such a situation, and it is possible to reliably determine whether a predetermined track is on the inner peripheral side or the outer peripheral side of a wobbled groove by using one laser beam. It is something that can be done.
[0014]
[Means for Solving the Problems]
The recording / reproducing apparatus according to claim 1, wherein a first offset signal for detracking the track to one side of the track and a second offset signal for detracking the other side of the track are recorded. Generating means, a first wobble signal obtained from the edge when tracking is detracked to one side of the track, and a second wobble signal obtained from the edge when detracked to the other side of the track And detecting means for determining whether the track is a track on one side of the edge or a track on the other side by comparing the first and second wobble signals. It is characterized by providing.
[0015]
4. The recording / reproducing method according to claim 3, wherein a first offset signal for detracking the track to one side of the track and a second offset signal for detracking the other side of the track are recorded. And the tracking detects the first wobble signal obtained from the edge when detracked to one side of the track and the second wobble signal obtained from the edge when detracked to the other side of the track Then, by comparing the first and second wobble signals, it is determined whether the track is a track on one side of the edge or a track on the other side.
The optical disk reproducing apparatus according to claim 4 is an irradiation unit that irradiates a track on the optical disk with a single light beam, a wobble signal generation unit that generates a wobble signal based on reflected light from the optical disk, and an irradiation unit. Generating means for generating a first offset signal for offsetting the light beam emitted from the means to the inner peripheral side and a second offset signal for offsetting to the outer peripheral side; and a wobble signal generating means for applying the first offset signal Comparing the wobble signal output from the wobble signal output from the wobble signal generating means when the second offset signal is applied, and the irradiation means based on the comparison result of the comparing means. And a discriminating means for discriminating whether the second track is irradiated.
6. The optical disk reproducing method according to claim 5, wherein a single light beam is irradiated to a track on the optical disk, a wobble signal is generated based on the reflected light from the optical disk, and the irradiated light beam is A first offset signal that is offset to the outer periphery and a second offset signal that is offset to the outer periphery are each applied, and a wobble signal that is generated when the first offset signal is applied and a second offset signal that is generated when the first offset signal is applied And comparing whether the first track is irradiated with a single light beam or whether the second track is irradiated with a single light beam based on the comparison result. It is characterized by.
[0016]
The recording / reproducing apparatus according to claim 1, wherein the generating means is configured to cause the tracking with respect to the track to be detracked to one side of the track and to detrack to the other side of the track. A second offset signal is generated, and the detection means obtains from the first wobble signal obtained from the edge when tracking is detracked to one side of the track and from the edge when detracked to the other side of the track; Whether the track is a track on one side of the edge or a track on the other side by comparing the first and second wobble signals. Determine.
[0017]
4. The recording / reproducing method according to claim 3, wherein the first offset signal for detracking the track to one side of the track and the second offset for detracking to the other side of the track. A first wobble signal obtained from the edge when a signal is generated and tracking is detracked to one side of the track; and a second wobble signal obtained from the edge when detracked to the other side of the track. By detecting and comparing the first and second wobble signals, it is determined whether the track is a track on one side of the edge or a track on the other side.
In the optical disk reproducing apparatus according to claim 4, an irradiating means for irradiating a track on the optical disk with a single light beam, a wobble signal generating means for generating a wobble signal based on reflected light from the optical disk, Generating means for generating a first offset signal for offsetting the light beam emitted from the irradiating means to the inner peripheral side and a second offset signal for offsetting to the outer peripheral side; and generating a wobble signal when the first offset signal is applied A comparing means for comparing the wobble signal output from the means with the wobble signal output from the wobble signal generating means when the second offset signal is applied, and the irradiating means based on the comparison result of the comparing means. And a discriminating means for discriminating whether the track is irradiated or the second track is irradiated.
In the optical disk reproducing method according to claim 5, a single light beam is irradiated to a track on the optical disk, a wobble signal is generated based on reflected light from the optical disk, and the irradiated light beam is A first offset signal that is offset to the outer side and a second offset signal that is offset to the outer peripheral side are each applied, and a wobble signal generated when the first offset signal is applied and a second offset signal when the second offset signal is applied The generated wobble signal is compared, and based on the comparison result, it is determined whether the first track is irradiated with a single light beam or the second track is irradiated with a single light beam. .
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the present invention will be described below. In order to clarify the correspondence between each means described in the claims and the following examples, the corresponding examples are shown in parentheses after each means. The characteristics of the present invention will be described with the addition of (one example). However, of course, this description does not mean that each means is limited to the description.
[0019]
The recording / reproducing apparatus according to claim 1 provides information to a recording medium in which a groove or land edge is wobbled by a common address of a track adjacent to one side and a track adjacent to the other side. In a recording / reproducing apparatus for recording or reproducing, a first offset signal for detracking a track to one side of the track and a second offset signal for detracking the other side of the track are generated. Generating means (for example, the offset signal generating circuit 10 in FIG. 1), and the tracking is detracked to the other side of the track, the first wobble signal obtained from the edge when detracked to one side of the track Detecting means for detecting the second wobble signal obtained from the edge (for example, the recording / reproducing process shown in FIG. 21) and the first and second wobble signals are compared to determine whether the track is a track on one side of the edge or a track on the other side (for example, FIG. 1). And a wobble signal detection circuit 9).
[0020]
FIG. 1 shows the configuration of an embodiment of the recording / reproducing apparatus 11 of the present invention. The data modulation circuit 1 converts predetermined input data into a code of a predetermined format to be recorded on the disk, and outputs the code to the recording head control circuit 2.
[0021]
The recording head control circuit 2 supplies a control signal to the recording / reproducing head 21 (FIG. 2) of the recording / reproducing unit 4 and applies the code supplied from the data modulation circuit 1 to the disk D (recording medium such as a magneto-optical disk). It is made to record.
[0022]
The recording / reproducing unit 4 records data (symbol) on the disk D in accordance with the control of the recording head control circuit 2, irradiates the disk D with laser light, and receives the reflected light on the disk D. Reads the recorded data (code) and outputs the data (code) to the data demodulation circuit 8 and generates a wobble signal including a tracking error signal, a focus error signal, and address information from the received reflected light. The tracking error signal and the focus error signal are output to the servo circuit 7 and the wobble signal is output to the wobble signal detection circuit 9.
[0023]
The wobble signal detection circuit 9 determines from the recording / reproducing unit 4 whether the track currently being recorded or reproduced has a wobbled groove on its inner peripheral side or a wobbled groove on its outer peripheral side. It discriminates from the supplied wobble signal, and outputs the signal of the discrimination result to the address decoder 5, converts the wobble signal supplied from the recording / reproducing unit 4 into an address information signal, and outputs it to the address decoder 5. Has been made.
[0024]
The wobble signal detection circuit 9 extracts a carrier signal from the wobble signal supplied from the recording / reproducing unit 4 and outputs the carrier signal to the servo circuit 7.
[0025]
The address decoder 5 calculates an address from the address information signal and the track discrimination signal supplied from the wobble signal detection circuit 9 and outputs the calculation result to the system controller 3.
[0026]
The system controller 3 outputs a predetermined control signal to the servo circuit 7 in accordance with the address supplied from the address decoder 5, and when a signal corresponding to a predetermined operation is supplied from the input device 6, the system controller 3 responds to the operation. The control signal is output to the servo circuit 7 to control the recording / reproducing unit 4. The system controller 3 instructs the offset signal generation circuit 10 to output a predetermined offset signal at the start of tracking for the predetermined track.
[0027]
The offset signal generation circuit 10 is configured to supply an offset signal for detracking a predetermined track to the inner circumference side and the outer circumference side in order to the servo circuit 7 in accordance with an instruction from the system controller 3. ing.
[0028]
The servo circuit 7 controls the drive unit 22 (FIG. 2) of the recording / reproducing unit 4 according to the focus error signal and the tracking error signal supplied from the recording / reproducing unit 4, and the entire optical head 34, By moving the objective lens 45 of the head 34, the focus and tracking of the laser beam used for data detection are adjusted.
[0029]
The servo circuit 7 controls the spindle motor 31 (FIG. 2) of the recording / reproducing unit 4 according to the rotation information from the wobble signal detection circuit 9 to rotate the disk D at a predetermined speed, and from the system controller 3. The recording / reproducing unit 4 is controlled in accordance with the control signal. Further, upon receiving the input of the offset signal from the offset signal generating circuit 10, the servo circuit 7 adds the offset signal to the tracking error signal supplied from the recording / reproducing unit 4, thereby tracking the predetermined track. Control is performed so that the track is detracked to the inner or outer peripheral side.
[0030]
The data demodulating unit 8 demodulates the data (data detection signal) read from the disk D by the recording / reproducing unit 4.
[0031]
FIG. 2 shows a configuration of an embodiment of the recording / reproducing unit 4. The magnetic head 33 and the optical head 34 of the recording / reproducing head 21 operate in response to the control signal supplied from the recording head control circuit 2 to generate a magnetic field and a laser beam, respectively, and record predetermined data on the disk D. It is made like that.
[0032]
The optical head 34 irradiates the disk D with laser light, receives the reflected light, and outputs an electrical signal corresponding to the received light amount to the signal processing unit 23.
[0033]
The drive unit 22 includes a spindle motor 31 that rotates the disk D, a mechanical deck 32 that moves the recording / reproducing head 21, and the like, and operates according to a control signal supplied from the servo circuit 7.
[0034]
The signal processing unit 23 processes a signal from the recording / reproducing head 21 to generate a data detection signal, a tracking error signal, a focus error signal, and a wobble signal, and outputs the data detection signal to the data demodulation circuit 8 for tracking. An error signal and a focus error signal are output to the servo circuit 7, and a wobble signal is output to the wobble signal detection circuit 9.
[0035]
FIG. 3 shows a configuration of an embodiment of the drive unit 22. The spindle motor 31 rotates the disk D fixed to the turntable 35. The mechanical deck 32 is configured to move the recording / reproducing head 21 in the radial direction of the disk D in accordance with a control signal from the servo circuit 7.
[0036]
FIG. 4 shows the configuration of an embodiment of the recording / reproducing head 21. In this figure, a laser diode 41 emits laser light. The laser light forms an image on a predetermined region of the recording layer of the disk D through the collimator lens 42, the grating 43, the beam splitter 44A, and the objective lens 45. The reflected light from the disk D enters the beam splitter 44A via the objective lens 45 again, and a part of the p-polarized component (for example, 30% of the p-polarized component) and all of the s-polarized component are extracted. The light enters the beam splitter 44B. The beam splitter 44 </ b> B makes a part of the incident laser light enter the lens 46 and the remaining most part enters the polarization beam splitter 50 via the half-wave plate 49. The polarization beam splitter 50 separates the incident laser light into an s-polarized component and a p-polarized component, and enters the lens 57A and the lens 58A.
[0037]
The laser beam output from the beam splitter 44A and incident on the lens 46 is incident on the photodiode 48A via the lens 47 that gives astigmatism to the beam, converted into an electrical signal corresponding to the intensity of the beam, and servo signal ( Focus error signal and tracking error signal) are output to the servo circuit 7 via the signal processing unit 23. The laser light emitted from the polarization beam splitter 50 is incident on the photodiode 48B and the photodiode 48C through the lenses 57A and 57B and the lenses 58A and 58B, respectively. These photodiodes 48B and 48C convert the incident laser light into a corresponding electrical signal and output it. The electrical signals output from the photodiodes 48B and 48C are differentially amplified and output to the data demodulation circuit 8 as a data detection signal via the signal processing unit 23.
[0038]
Since the return light for data detection changes in polarization state according to the data recorded on the disk, the data can be detected from the difference between the polarization components received by the photodiodes 48B and 48C.
[0039]
The magnetic head 33 is arranged at a position facing the objective lens 45 with the disk D interposed therebetween, and applies a magnetic field corresponding to the recording position to the disk D.
[0040]
FIG. 5 is a diagram showing an example of the configuration of a disc D that can record or reproduce information using the recording / reproducing apparatus 11 of the present invention. As shown in FIG. 5, each of the land L and the groove G forms one spiral and is alternately arranged in the radial direction. In the groove G, a wobbling groove G-1 and a non-wobbling groove G-2 (DC groove) are alternately arranged for every round. In the disk D, the land L is a track (recording area), and data is recorded on or reproduced from the land L (while the groove G is an unrecorded area). Further, since the groove G is an unrecorded area, the groove G is formed to be narrower than the land L. The groove G-1 includes addresses of tracks (land L) on both sides thereof.
[0041]
Next, a specific processing operation of the recording / reproducing apparatus 11 of FIG. 1 will be described with reference to the flowchart of FIG.
[0042]
When the system controller 3 is instructed to record or reproduce predetermined information via the input device 6 of the recording / reproducing apparatus 11, in step S1 in FIG. 6, the system controller 3 performs tracking for a track at a predetermined address. To the servo circuit 7. In response to this instruction command, the servo circuit 7 controls the recording / reproducing unit 4 so that the track of the designated address is tracked.
[0043]
The wobble signal detected at this time will be described with reference to FIGS. FIG. 7 shows a state in which the laser light emitted from the objective lens 45 is condensed at the center of a predetermined track (land L), that is, a state in which normal tracking is performed. As shown in FIG. 7, the center of the spot is located on the land L, and the wobble signal is reflected light from both sides of the spot. In the state shown in FIG. 7, the reflected light from the region A and the region B The reflected light is converted into a predetermined electric signal and supplied to the wobble signal detection circuit 9. The wobble signal detection circuit 9 compares the signal levels of the two to determine whether the track is on the inner side or the outer side of the groove G-1. The wobble signal (amplitude W0) at this time is shown in FIG.
[0044]
In subsequent step S2, the system controller 3 causes the offset generation circuit 10 to output an offset signal for detracking the track being tracked by a predetermined amount toward the outer periphery. When this offset signal is supplied to the servo circuit 7, the servo circuit 7 adds (or differentially amplifies) this offset signal to the tracking error signal detected by the photodiode 48A of the recording / reproducing unit 4. ) Using the generated new tracking error signal, the recording / reproducing unit 4 is controlled so that the tracking is detracked by a predetermined amount toward the outer peripheral side.
[0045]
9 and 10 show the spot position and the detected wobble signal at this time, respectively. That is, in response to the generated tracking error signal (signal generated by adding the offset signal), the optical head 34 moves so as to detrack to the outer peripheral side, so that the spot position shown in FIG. Moves to the spot position shown in FIG. As a result, since the component of the groove G-1 included in the reflected light from the region A is decreased, the level of the wobble signal (amplitude Win) is compared with the level of the wobble signal in FIG. 8 as shown in FIG. (Amplitude Win <amplitude W0).
[0046]
In subsequent step S3, the system controller 3 causes the offset generation circuit 10 to output an offset signal for detracking the track being tracked by a predetermined amount toward the inner circumference. As in the case of step S2, when this offset signal is supplied to the servo circuit 7, the servo circuit 7 generates a new tracking error signal and uses this to track the inner circumference side by a predetermined amount. The recording / reproducing unit 4 is controlled to detrack.
[0047]
FIGS. 11 and 12 show the spot position and the detected wobble signal at this time, respectively. That is, the spot position moves to the spot position shown in FIG. 11 by moving the optical head 34 so as to detrack toward the inner circumference side in response to the generated tracking error signal. As a result, since the component of the groove G-1 included in the reflected light from the region A increases, as shown in FIG. 12, the level of the wobble signal (amplitude Wout) is compared with the level of the wobble signal in FIG. (Amplitude W0 <amplitude Wout).
[0048]
  Subsequently, in step S4, the wobble signal detection circuit 9 compares the amplitude Win with the amplitude Wout to determine whether the track being tracked is the track on the inner circumference side of the groove G-1. It is determined whether the track is on the outer peripheral side. That is, when the amplitude Wout is larger than the amplitude Win,Inner circumferenceWhen the track is detracked, the level of the wobble signal becomes larger (the groove G-1 becomes closer), so that the track on which the tracking was performed is the groove G-1.Outer peripheral sideIt is determined that it is a track. Conversely, when the amplitude Win is greater than the amplitude Wout,Outer peripheral sideWhen the track is detracked, the level of the wobble signal becomes larger (the groove G-1 becomes closer), so that the track on which the tracking was performed is the groove G-1.Inner circumferenceIt is determined that it is a track.
[0049]
In subsequent step S5, the system controller 3 uses the discrimination result and address information supplied from the wobble signal detection circuit 9 via the address decoder 5 to determine whether or not the recording / reproducing head 21 exists at the target position. to decide. If it is determined that the recording / reproducing head 21 does not exist at the target position, the recording / reproducing head 21 is moved in the direction of the target position in step S6, and the processes after step S1 are repeated.
[0050]
If it is determined in step S5 that the recording / reproducing head 21 is present at the target position, the process branches to step S7, and information recording or reproduction processing on the disk D is executed in step S7. That is, the system controller 7 instructs the servo circuit 7 to perform tracking servo and focusing servo for the target track. In response to this instruction signal, the servo circuit 7 performs optimum tracking based on the tracking error signal and the focus error signal generated using the reflected light of the laser beam detected by the photo detector 48A of the recording / reproducing unit 4. And controlling focusing.
[0051]
  Here, a method of generating a tracking error signal, a focus error signal, and an address signal will be described with reference to FIG. FIG. 13 shows a state in which a portion in the vicinity of the spot irradiated with the laser light is enlarged. Now, as shown in FIG. 13, it is assumed that the laser beam is applied to the nth track. And the nth track and the nth trackn-1A groove G-1 including address information of both tracks is formed between the tracks, that is, on the inner circumference side of the nth track.
[0052]
In the state shown in FIG. 13, the focus error signal is generated from a signal (A + C) obtained by adding a signal from the region A and the region C located diagonally thereto, and from the region B and the region D located diagonally thereto. Is generated using a difference ((A + C) − (B + D)) from the signal (B + D) obtained by adding the above signal. The tracking error signal includes a signal (A + D) obtained by adding the signals from the areas A and D on one side and a signal (B + C) obtained by adding the signals from the areas B and C on the other side. ) And ((A + D)-(B + C)). However, it is assumed that the tracking error offset that occurs when the field of view is shaken does not occur, for example, when the pickup and the objective lens are integrated.
[0053]
Similarly to the tracking error signal, the address signal is a signal (A + D) obtained by adding signals from the areas A and D on one side, and a signal obtained by adding signals from the areas B and C on the other side. A band-pass filter for a difference ((A + D)-(B + C)) from (B + C) or a signal (A + B + C + D) obtained by adding signals from regions A to D Thus, a wobble carrier frequency signal (wobble signal) is extracted and generated by FM demodulation.
[0054]
In this manner, information recording or reproduction processing is performed on the target position (the position on the inner or outer periphery side of the predetermined address) of the disk D.
[0055]
In the flowchart of FIG. 6, the reading of the address signal is performed in step S1, but since the reading process of the address signal takes time, it may be performed in parallel with the processing of steps S1 to S4. Good.
[0056]
As a recording medium for recording or reproducing information using the recording / reproducing apparatus 11, tracks on both sides of the land or groove wobbled according to the address information are held in the wobbling land or groove. Any recording medium that shares an address may be used.
[0057]
For example, as shown in FIG. 14, in the recording / reproducing apparatus 11, the land L and the groove G are formed on one independent continuous spiral, and only one wall of the land L or the groove G is addressed. As shown in FIG. 15, only one wall of the land L or the groove G is wobbled corresponding to the address information, and one land L and one groove G are provided. Information can be recorded or reproduced also on the disk D2 alternately arranged on the spiral. Of course, the recording / reproducing apparatus 11 can record or reproduce information also on the disk D0 of FIG.
[0058]
As described above, it is possible to accurately determine whether the track being tracked is an inner track or an outer track of the land or groove being wobbled by using one laser beam. Can be determined.
[0059]
In addition, since it is possible to detrack the inner circumference side or the outer circumference side simply by adding a predetermined offset signal to the tracking error signal, a relatively simple circuit configuration and a low-cost recording / reproducing apparatus 11 can be realized. be able to.
[0060]
In the above embodiment, the focus servo is performed using the astigmatism method and the tracking servo is performed using the push-pull method. However, the present invention is not limited to using other servo methods. Can also be applied. In the above embodiment, the wobble signal when detracked to the inner circumference side is compared with the wobble signal when detracked to the outer circumference side. The wobble signal when the inner track side or the outer track side is detracked may be compared.
[0061]
【The invention's effect】
As aboveThe present inventionGenerating a first offset signal for detracking the track to one side of the track and a second offset signal for detracking the other side of the track, By detecting and comparing the first wobble signal obtained from the edge when detracked to one side of the track and the second wobble signal obtained from the edge when detracked to the other side of the track, Since it is determined whether the track is a track on one side of the edge or a track on the other side, the determination result can be accurately obtained by using one laser beam.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of a recording / reproducing apparatus 11 of the present invention.
FIG. 2 is a block diagram showing a configuration of an embodiment of a recording / reproducing unit 4;
FIG. 3 is a block diagram showing a configuration of an example of a drive unit 22;
4 is a block diagram showing a configuration of an embodiment of a recording / reproducing head 21. FIG.
FIG. 5 is a diagram showing a configuration of an embodiment of a disk D capable of recording or reproducing information using the recording / reproducing apparatus 11 of the present invention.
FIG. 6 is a flowchart for explaining the processing operation of the recording / reproducing apparatus 11;
FIG. 7 is a diagram illustrating a state in which tracking is performed on a predetermined track.
8 is a diagram showing a signal level of a wobble signal at the position of the laser beam shown in FIG.
9 is a diagram showing a state in which the position of the laser beam is detracked from the position shown in FIG. 7 to the outer peripheral side.
10 is a diagram showing a signal level of a wobble signal at the position of the laser beam shown in FIG.
11 is a view showing a state in which the position of the laser beam is detracked from the position shown in FIG. 7 to the inner circumference side.
12 is a diagram showing a signal level of a wobble signal at the position of the laser beam shown in FIG.
FIG. 13 is a diagram illustrating a method for generating a tracking error signal, a focus error signal, and an address signal.
FIG. 14 is a diagram showing a configuration of another embodiment of a disc D that can record or reproduce information using the recording / reproducing apparatus 11 of the present invention.
FIG. 15 is a diagram showing a configuration of still another embodiment of a disk D that can record or reproduce information using the recording / reproducing apparatus 11 of the present invention.
FIG. 16 is a diagram showing a configuration of a disk D1 in which a wobbling groove G-1 and a non-wobbling groove G-2 each form an independent spiral.
17 is a diagram for explaining a method of reproducing an address signal stored in the disk D1 shown in FIG.
[Explanation of symbols]
D, D0, D1, D2 disc, 1 data modulation circuit, 2 recording head control circuit, 3 system controller, 4 recording / playback unit, 5 address decoder, 6 input device, 7 servo circuit, 8 data demodulation circuit, 9 wobble signal Detecting circuit 10, Offset signal generating circuit 11, Recording / reproducing device, 21 Recording / reproducing head, 22 Drive unit, 23 Signal processing unit, 31 Spindle motor, 32 Mechanical deck, 33 Magnetic head, 34 Optical head, 35 Turntable, 41 Laser Diode, 42 Collimator lens, 43 Grating, 44A, 44B Beam splitter, 45 Objective lens, 46, 47 Lens, 48A, 48B, 48C Photo diode, 49 Half-wave plate, 57A, 57B, 58A, 58B The lens

Claims (5)

In a recording / reproducing apparatus for recording or reproducing information on a recording medium in which the edge of a groove or land is wobbled by a common address of a track adjacent to one side and a track adjacent to the other side,
Generating means for generating a first offset signal for detracking the track to one side of the track and a second offset signal for detracking the other side of the track;
When tracking detracks to one side of the track, it detects a first wobble signal obtained from the edge and a second wobble signal obtained from the edge when detracked to the other side of the track Detecting means for
And determining means for comparing the first and second wobble signals to determine whether the track is a track on one side of the edge or a track on the other side. Recording / playback device. The recording / reproducing apparatus according to claim 1, wherein the detection unit detects the first and second wobble signals using reflected light of one light beam irradiated on the recording medium. In a recording / reproducing method for recording or reproducing information on a recording medium in which the edge of a groove or land is wobbled by a common address of a track adjacent to one side and a track adjacent to the other side,
Generating a first offset signal for detracking the track to one side of the track and a second offset signal for detracking the other side of the track;
When tracking detracks to one side of the track, it detects a first wobble signal obtained from the edge and a second wobble signal obtained from the edge when detracked to the other side of the track And
A recording / reproducing method comprising: comparing the first and second wobble signals to determine whether the track is a track on one side of the edge or a track on the other side. The inner wall surface of the track meanders, and the first track whose outer side surface is flat and the second track whose outer side surface meanders and whose inner side surface is flat are alternately arranged. In an optical disc playback apparatus for playing back information recorded on a track on an optical disc,
  Irradiating means for irradiating a track on the optical disc with a single light beam;
  Wobble signal generating means for generating a wobble signal based on reflected light from the optical disc;
  Generating means for generating a first offset signal for offsetting the light beam emitted from the irradiating means to the inner peripheral side and a second offset signal for offsetting to the outer peripheral side;
  Comparison means for comparing the wobble signal output from the wobble signal generation means when applying the first offset signal with the wobble signal output from the wobble signal generation means when applying the second offset signal;
  Determining means for determining whether the irradiating means irradiates the first track or the second track based on a comparison result of the comparing means;
  An optical disc reproducing apparatus comprising: The inner wall surface of the track meanders, and the first track whose outer side surface is flat and the second track whose outer side surface meanders and whose inner side surface is flat are alternately arranged. In an optical disc playback apparatus for playing back information recorded on a track on an optical disc,
  Irradiating the track on the optical disc with a single light beam,
  Generate a wobble signal based on the reflected light from the optical disc,
  Applying a first offset signal for offsetting the irradiated light beam to the inner circumference side and a second offset signal for offsetting to the outer circumference side, respectively;
  Comparing the wobble signal generated when applying the first offset signal and the wobble signal generated when applying the second offset signal;
  Whether the first track is irradiated with a single light beam based on the comparison result Or whether the second track is irradiated with a single light beam
  An optical disc reproducing method characterized by the above.

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