JP4348667B2 - Optical disc and recording / reproducing apparatus thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention includes a two-layer recording layer configured to be able to return the focus to the original recording layer when the focus moves to another recording layer due to vibration or the like during recording and reproduction. The present invention relates to an optical disc and a recording / reproducing apparatus thereof.
[0002]
[Prior art]
In recent years, an optical disc in which a plurality of recording layers are stacked has been proposed in order to increase the capacity of the optical disc. For example, there is an optical disc having two recording layers.
A conventional optical disc will be described with reference to FIGS.
7A and 7B show an optical disc having two conventional recording layers, where FIG. 7A is a cross-sectional view and FIG. 7B is an enlarged plan view of the surface thereof.
FIG. 8 is a plan view showing each zone of the optical disc.
FIG. 9 is a diagram showing a configuration of a land pre-pit block.
As shown in FIGS. 7 and 8, the conventional optical disc is formed by sequentially laminating a first recording layer 1b and a second recording layer 1c on a transparent substrate 1a, and recording areas of these recording layers 1b and 1c. Are divided into N zones concentrically on the disk.
On the first and second recording layers 1b and 1c, grooves G11, G12, G13, G21, G22 and G23 are formed concentrically or spirally, and the grooves G11, G12, G13, G21 and G22 are formed. , G23, and lands L11, L12, L13, L21, L22, and L23 are formed, and the lands L11, L12, L13, L21, L22, and L23 have grooves G11, G12, G13, and G21. , G22 and G23 are formed with an information recording section in which auxiliary information used when recording or reproducing information signals is recorded in advance as land prepits.
[0003]
The grooves G11, G12, G13, G21, G22, and G23 are continuously wobbled at a constant frequency in the disk circumferential direction, and the wobble phases adjacent in the disk radial direction are always the same in each of the plurality of zones. It is. Further, in the lands L11, L12, L13, L21, L22, and L23, prepit groups including a plurality of land prepits arranged for each wobble cycle are formed.
This pre-pit group is recorded at a position where the phase in the disk circumferential direction is different between adjacent land portions via grooves in the disk radial direction. Also, the presence or absence of land prepits is assigned to bits 1 and 0 to form one prepit group with 3 bits.
[0004]
For example, modulation is performed as follows, and recording is performed at a predetermined land position.
Sync signal 1 0
111 110 101
The upper stage synchronization signal, 1, 0 corresponds to data, the lower stage is a modulation signal, 1 means a land pre-pit, and 0 means no. In this way, auxiliary information including address information can be recorded using the land pre-pits.
[0005]
Further, since the wobble described above is recorded at a constant angular velocity (CAV) for each zone, this optical disk constitutes a ZCLV (Zone Constant Linear Velocity) system or a ZCAV (Zone Constant Angular Velocity) system. For this reason, the wobble phase is reversed between adjacent tracks, and reproduction data deterioration caused by a decrease in the track pitch does not occur. In addition, the land pre-pit signal does not have a problem due to the wobble having an opposite phase.
[0006]
As shown in FIG. 9, the structure of the land pre-pit block is completed by 32 sectors, and the 32 sectors are composed of a sync, a relative address, a block address, a zone address, additional information, and an error correction code.
When performing recording / reproduction of the optical disk, the recording medium is defocused due to dirt, dust, scratches, etc. on the disk or impact on the recording / reproducing apparatus. An optical disk apparatus that returns to the recording layer before defocusing is disclosed in Japanese Patent Laid-Open No. 8-18537, although it may move to the recording layer 1c.
[0007]
That is, JP-A-8-185637 discloses an input terminal to which an external focus error signal is supplied by recording or reproduction, a defocus detection circuit for detecting defocus based on the focus error signal, a recording or reproduction A recording layer designating unit for designating a recording layer to be reproduced, a memory for storing recording layer designating data indicating the recording layer designated by the recording layer designating unit, and a focus before defocusing when defocusing occurs From an acceleration / deceleration pulse generation circuit that outputs an acceleration / deceleration pulse for refocusing the recording layer, a changeover switch that switches and outputs the focus error signal and the acceleration / deceleration pulse, and a defocus detection circuit System controller that performs changeover control of changeover switch based on detection output of Compares the focus error signal with a reference signal of a predetermined level, supplies the comparison signal to the system controller, and when out-of-focus is detected, recording / reproduction from the out-of-focus recording layer Data output is stopped, the system controller reads the recording layer designation data in the memory, and based on the recording / reproducing data from the recording layer that is out of focus, detects the recording layer that has been recorded / reproduced by defocusing, and this recording Compares the layer specification data with the data indicating the recording layer recorded / reproduced by defocusing, and creates recovery data indicating how many layers should be skipped to return focus to the recording layer before defocusing Based on this recovery data, the focus jump is performed using the acceleration / deceleration pulse generation circuit. Optical disc apparatus is disclosed readjust the focus before recording layer off focus.
[0008]
[Problems to be solved by the invention]
However, when defocusing occurs from the first recording layer 1b to the second recording layer 1c, the additional information of the land pre-pit block of the second recording layer 1c is read in order to refocus the first recording layer 1b. After that, it is necessary to create recovery data, and it takes time. Therefore, it was not possible to quickly refocus the first recording layer 1b.
Further, in the case of the optical disc 1 shown in FIGS. 7 to 9, there has been a problem that the information signal of the groove for at least 32 sectors is rewritten.
[0009]
The present invention has been made in view of the above-mentioned problems, and when out of focus occurs during recording / reproduction of an optical disc having two recording layers, the rewrite of the groove information signal is reduced, and the focus is lost. It is an object of the present invention to provide an optical disc and a recording / reproducing apparatus thereof that can quickly refocus on the previous recording layer.
[0010]
According to a first aspect of the present invention, there is provided a recording layer comprising a groove formed concentrically or spirally from the innermost circumference to the outermost circumference and land portions continuously formed between the grooves. The land portion has an information recording portion in which auxiliary information used for recording or reproducing information signals in the groove is recorded in advance as land prepits, and the information recording portion has a disc radius. The groove is divided into a plurality of zones in advance, the groove is continuously wobbled at a constant frequency on both sides of the groove in the disk circumferential direction, and the plurality of zones in each of the two recording layers In each of these, the phase of the wobble of the groove adjacent in the disk radial direction is always the same phase, and a plurality of the labels arranged in the land portion for each period of the wobble. Prepit group consisting Dopuripitto is recorded at a position where the phase of the disk circumferential direction are different between the land portions adjacent in the radial direction of the disk, In the first recording layer, the land prepits are arranged at the peak position of the wobble disc on the inner circumference side, and in the second recording layer, the land prepits are arranged at the peak position on the outer circumference side of the wobble disc. Pits are arranged, or the land pre-pits are arranged at the peak position on the outer circumference side of the wobble disc in the first recording layer, and the wobble disc is arranged in the second recording layer. The land pre-pit is located at the inner peripheral peak position. Provided is an optical disc characterized by being arranged.
According to a second aspect of the present invention, there are provided two recording layers each having a groove formed concentrically or spirally from the innermost circumference to the outermost circumference, and land portions continuously formed between the grooves. The groove has an information recording portion in which auxiliary information used when recording or reproducing information signals on the land portion is recorded in advance as a groove preland, and the information recording portion is previously provided in the radial direction of the disc. The land portion is divided into a plurality of zones, and both sides of the land portion are continuously wobbled at a constant frequency in the disk circumferential direction, and each of the plurality of zones in each of the two recording layers Each of the land portions adjacent to each other in the radial direction of the disk always has the same wobble phase, and a plurality of the grooves arranged in the groove at every wobble cycle. Groove pre lands group consisting Leland is recorded at a position where the phase of the disk circumferential direction are different between the land portions adjacent in the radial direction of the disk, In the first recording layer, the groove preland is disposed at a peak position on the inner circumference side of the wobble, and in the second recording layer, the groove preland is located on a peak position on the outer circumference side of the wobble. A land is disposed, or the groove pre-land is disposed at a peak position on the outer circumference side of the wobble disc in the first recording layer, and the wobble disc is disposed in the second recording layer. The groove pre-land is located at the inner peripheral peak position. Provided is an optical disc characterized by being arranged.
The third invention is Invention described above In an optical disc recording / reproducing apparatus for recording / reproducing optical discs of the above-mentioned optical discs, land wobbles arranged at the peak positions on the inner or outer peripheral side of the wobble are described. Or A layer discrimination and pre-pit signal extraction means for outputting a layer discrimination signal from the inner circumference side pre-pit detection signal or the outer circumference side pre-pit detection signal and the binarized wobble signal of the wobble, and the layer discrimination signal and recorded in advance Compared with the layer indication signal that indicates the layer, if this result is different, it is determined that the focus has been lost, and the focus jump control is performed to refocus the recording / playback layer before the focus is lost. And an optical disc recording / reproducing apparatus.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of an optical disc and a recording / reproducing apparatus thereof according to the present invention will be described below with reference to FIGS.
FIG. 1 is an enlarged plan view of an optical disc according to an embodiment of the present invention.
FIG. 2 is a block diagram showing the optical disc recording / reproducing apparatus in the embodiment of the present invention.
FIG. 3 is a block diagram showing layer discrimination and pre-pit signal extraction means used in the optical disk recording / reproducing apparatus.
FIG. 4 is a block diagram showing focus control means used in the optical disc recording / reproducing apparatus.
FIG. 5 is a diagram showing operation waveforms for explaining the operation of the first recording layer of the optical disc recording / reproducing apparatus in the embodiment of the present invention.
FIG. 6 is a diagram showing operation waveforms for explaining the operation of the second recording layer of the optical disc recording / reproducing apparatus in the embodiment of the present invention.
The same components as those of the conventional example are denoted by the same reference numerals, and the description thereof is omitted.
[0012]
In the optical disc 1 in the embodiment of the present invention, in the conventional optical disc shown in FIG. 7, in the first recording layer 1b, land pre-pits are arranged at the peak position of the wobble of the wobble in the groove, and in the second recording layer 1c. However, the land pre-pits are arranged at the peak positions on the outer peripheral side of the wobbles in the groove, and the rest is the same.
[0013]
The auxiliary information corresponding to the information recording signal recorded in the groove G12 of the first recording layer 1b is read from the land pre-pits arranged at the peak position on the inner circumference side of the groove, and the second recording layer 1c. The auxiliary information corresponding to the information recording signal recorded in the groove G22 is read from the land pre-pit arranged at the peak position on the disk outer circumference side of the groove.
[0014]
Hereinafter, since the land pre-pit L11 is disposed inside the groove G12 in which the information signal is recorded, it is referred to as an inner peripheral land pre-pit, and the land pre-pit L22 is disposed outside the groove G22. This is called the outer side land pre-pit. The prepit signal detected from the inner land prepit is referred to as an inner peripheral prepit signal, and the prepit signal detected from the outer land prepit is referred to as an outer prepit signal.
Thus, by detecting the recording position relationship between the polarity of the wobble signal and the land pre-pit, it is determined whether the recording / reproduction is performed in the first recording layer 1b or the second recording layer 1c. Can be determined.
[0015]
Next, the optical disk recording / reproducing apparatus of the present invention will be described with reference to FIG.
As shown in FIG. 2, the optical disc recording / reproducing apparatus of the present invention includes a spindle motor 2 for rotating the optical disc 1 and a photodetector for irradiating the optical disc 1 with a light beam spot S and detecting reflected information light. 5, an optical pickup 21 having a track 5, a track deviation detecting means 6 for detecting a positional deviation between the light beam spot S and a track (here, a groove) from the information light by a push-pull method and outputting a tracking signal; Tracking control means 7 for controlling the light beam spot S to follow the track according to the track deviation detection signal output from the deviation detection means 6, and the position of the light beam spot S in a direction substantially orthogonal to the track direction of the optical disc 1. The moving means 8 moving in the (track width direction) and the output of the light detector 5 and the light beam spot S A focus error deviation detecting means 9 for detecting the position deviation of the groove by a so-called astigmatism method, an inner circumference side prepit detecting means 10 for detecting an inner circumference land prepit signal for the groove being recorded and reproduced, and a recording and reproduction process. The outer periphery side prepit detection means 11 for detecting the outer periphery side land prepit signal with respect to the inner groove, the wobble signal detection means 12 for detecting the wobble signal from the output signal of the photodetector 5, and the wobble signal are binarized. The recording layer being recorded / reproduced is discriminated from the binarizing means 13, the output of the inner peripheral side prepit detecting means 10, the output of the outer periphery prepit detecting means 11, and the output of the binarizing means 13, and simultaneously recording / reproducing is being performed. A layer discrimination and prepit extraction means 14 for extracting a prepit corresponding to the groove and outputting a layer discrimination and prepit detection signal, and a focus error deviation signal Focus control means 15 for correcting out-of-focus by FE and layer discrimination signal, reference clock generating means 16 for controlling rotation of spindle motor 2, and rotation control of spindle motor 2 based on frequency of wobble signal and reference clock Motor control means 17 for performing recording, clock generating means 18 for generating a bit clock at the time of recording from the binarized wobble signal and the pre-pit signal, and recording data on the basis of the bit clock output from the clock generating means 18 The recording processing means 19 for converting into a format and the recording means 20 for converting into a predetermined recording waveform based on the format conversion signal output from the recording processing means 19 are provided.
[0016]
The optical pickup 21 includes a light source 3 such as a semiconductor laser for irradiating the light beam spot S, an objective lens 4 for condensing the light beam spot S on the optical disk 1, and a direction tangential to the tangential direction of the groove of the optical disk 1. It has a four-divided light receiving section A, B, C, D divided by a dividing line, and it collects the light emitted from the light detector 3 and the light source 3 for detecting the reflected light irradiated on the optical disk 1 on the optical disk 1. An optical system that guides light or the light detector 5 is integrated, and is driven by the moving means 8 to move in the radial direction of the optical disk 1.
Of the four divided light receiving portions A, B, C, and D of the photodetector 5, the divided light receiving portion A and the divided light receiving portion C are in a diagonal position relationship with each other. It is in angular position relationship. Here, A, B, C, and D also represent the amount of light received by the four-divided light receiving unit.
[0017]
Next, a specific configuration of the above-described layer discrimination and prepit extraction means 14 will be described with reference to FIG.
The layer discriminating and prepit extracting means 14 inputs the inner circumference prepit detection signal S2 outputted from the inner circumference side prepit detection means 10 and the outer circumference side prepit detection signal S3 outputted from the outer circumference side prepit detection means 11, The first logical sum means 141 that outputs the both-side prepit detection signal S4 and the binary prepit detection signal S4 and the binarized wobble signal S5 output from the wobble signal detection means 12 are input, A second logical sum means 142 that takes these logical sums and outputs a pre-pit polarity detection signal S6, a peak hold circuit 143 that peaks from the pre-pit polarity detection signal S6 and outputs a layer discrimination signal, and a discrimination result In the case of the first recording layer 1b, the inner peripheral side prepit detection signal S2, and in the case of the second recording layer 1c, the outer peripheral side prepit. And a selection circuit 144 that selects the detection signal S3 and outputs a pre-pit detection signal S8.
[0018]
Next, a specific configuration of the focus control means 15 will be described with reference to FIG.
As shown in FIG. 4, the focus control means 15 includes an input terminal 151 to which a focus error signal (indicated by FE in the figure) detected by the photodetector 5 is supplied during recording / reproduction, An input terminal 152 to which a layer discrimination signal output from the pre-pit signal detection means 14 is supplied, and a layer from a controller (not shown) that specifies in advance which recording / reproduction of the first recording layer 1b or the second recording layer 1c is performed. The input terminal 153 to which the instruction signal is supplied is compared with the layer instruction signal and the layer discrimination signal. If the comparison results are different, it is determined that the focus has been lost, and the focus is applied to the recording layer before the focus is removed. A focus jump control means 154 that generates a focus jump control signal so as to repeat and outputs a switching control signal, The focus jump signal generating means 155 for generating the focus jump interlayer signal based on the focus control signal, and the terminal a to which the focus error signal is supplied by the switching control signal from the focus jump control means 154 And a selector switch 156 for switching the terminal b to which the focus jump interlayer signal is supplied.
[0019]
Next, the operation of this optical disk recording / reproducing apparatus will be described with reference to FIGS.
First, recording when the focus is on the first recording layer 1b will be described.
As shown in FIG. 2, the optical disk 1 rotated by the spindle motor 2 is irradiated with the light beam spot S from the light source 3 of the optical pickup 21, and the reflected light from the light beam spot S collected by the objective lens 4 on the optical disk 1. Is received by the photodetector 5. Thereafter, a photoelectric conversion is performed by the photodetector 5, and a received light signal having a level corresponding to the amount of reflected light received is detected as a track deviation detection means 6, a focus deviation detection means 9, an inner circumference side prepit detection means 10, and an outer circumference side prepit detection. It outputs to the means 11 and the wobble signal detection means 12, respectively.
[0020]
From the track deviation detection means 6, the (A + D) − is detected by a known push-pull method based on the level difference of the received light signals detected by the four-divided light receiving portions A, B, C, D of the photodetector 5. A track deviation detection signal TE is generated from (B + C) and output to the tracking control means 7.
From the defocus detection means 9, the known astigmatism method is used to calculate (A + C) based on the level difference of the received light signals detected by the four-divided light receiving sections A, B, C, and D of the photodetector 5. A focus deviation detection signal FE is generated from − (B + D) and output to the focus control means 15.
[0021]
From the inner periphery side prepit detection means 10 and the outer periphery side prepit signal detection means 11, a difference signal (based on the level difference of the received light signals detected by the four-divided light receiving portions A, B, C, and D of the photodetector 5 is obtained. A + D) − (B + C) is generated, a prepit signal is detected at a slice level provided according to the amplitude and polarity of the wobble, and is output to the layer discrimination and prepit signal extraction means 14.
[0022]
From the wobble signal detection means 12, a difference signal (A + D)-(B + C) based on the level difference of the received light signals detected by the four-divided light receiving portions A, B, C, D of the photodetector 5. The wobble frequency component is frequency-selected from the difference signal, the wobble signal is extracted, the binarization means 13 binarizes the wobble signal, and the binarized wobble signal is output.
[0023]
As shown in FIG. 3, the layer discrimination and prepit signal extraction means 14 includes an inner circumference prepit signal S2 outputted from the inner circumference prepit detection means 10 and an outer circumference prepit signal S3 outputted from the outer circumference prepit detection means 11. Based on the binarized wobble signal S5 output from the binarizing means 13, a layer discrimination signal S7 and a prepit detection signal S8 are generated, the layer discrimination signal S7 is used as the focus control signal 15, and the prepit detection signal S8 is used as the prepit detection signal S8. Each is output to the clock generation means 18.
[0024]
The inner circumference side prepit signal S2 and the outer circumference side prepit detection signal S3 are input to the first OR circuit 141 and the selection circuit 144. In the selection circuit 144, the inner peripheral side prepit signal S2 is input to the terminal a, and the outer peripheral side prepit signal S3 is input to the terminal b. The first logical sum means 141 takes the logical sum of these signals, generates a both-side pre-pit detection signal S4, and outputs it to the second logical sum means 142. The second logical sum means 142 takes the logical sum of the both-side pre-pit detection signal S4 and the binarized wobble signal S5 to generate the pre-pit polarity detection signal S6, and then holds the peak in the peak hold circuit 143 and performs the layer discrimination signal S7. Is output to the selection circuit 144 and the focus control means 15.
[0025]
In the selection circuit 144, when the layer determination signal S7 is the first recording layer 1b, the terminal a of the selection circuit 144 to which the inner peripheral side prepit detection signal S2 is input is selected, and the layer determination result is the second. In the case of the recording layer 1c, the terminal b of the selection circuit 144 to which the outer peripheral prepit detection signal S3 is input is selected, and either the inner peripheral prepit detection signal S2 or the outer peripheral prepit detection signal S3 is selected. The pre-pit detection signal S8 is output to the clock generation means 18.
[0026]
As shown in FIG. 4, the focus control means 15 inputs the focus shift detection signal FE to the terminal a of the changeover switch 156 via the input terminal 151, while the layer discrimination signal detected by the layer discrimination and prepit signal extraction means 14. S7 is input to the focus jump control means 154 via the input terminal 152 and a layer instruction signal output from a controller (not shown) via the input terminal 153.
[0027]
The focus jump control means 154 compares the layer determination signal S7 with the layer instruction signal. If the comparison results are different, it is determined that the focus has been lost, and the focus is refocused on the recording layer before the focus is lost. While outputting the jump control signal to the focus jump signal generating means 155, the switching control signal is output to the changeover switch 156. The focus jump signal generating means 155 receives the focus jump control signal and outputs an interlayer focus jump signal to the terminal b of the changeover switch 156.
Then, the switching switch 156 is switched to the terminal b, and an interlayer focus jump signal can be input to the optical pickup 21 to refocus the recording layer before defocusing occurs. When the focus returns to the recording layer before defocusing, the focus jump control means 154 outputs a switching control signal to return the changeover switch 156 to the terminal a, and returns to the state before defocusing.
[0028]
The clock generation means 18 divides the binary wobble signal S5 to generate a bit clock frequency, and at the same time, phase-synchronizes with the bit clock frequency based on the pre-pit detection signal S8 detected by the layer discrimination and pre-pit signal extraction means 14. And a bit clock for recording is output to the recording processing means 19.
In the recording processing unit 19, the recording information is configured in a predetermined recording format based on the bit clock, and the recording unit 20 records the information on the optical disc 1 by using the optical pickup 21 with a predetermined recording waveform.
[0029]
At this time, the spindle is controlled by inputting the reference clock output from the reference clock generating means 16 and the binarized wobble signal output from the binarizing means 13 to the motor control means 17 and within the same zone. The rotation of the spindle motor 2 is controlled so that the wobble frequency is always constant, and the wobble frequency is rotated at a constant angular velocity in the same zone.
In the case of ZCLV control, the linear velocity is constant in all zones by keeping the wobble frequency constant throughout the entire disk. In the case of ZCAV control, the angular velocity is constant in all zones by changing the wobble frequency for each zone and making the rotation speed constant for the entire disk.
[0030]
Reproduction is performed as follows.
In FIG. 2, the reproduction system is not shown. The reproduction system has a known configuration in which a reproduction signal is obtained based on a signal detected by a photodetector 5 that is the same as or different from the photodetector 5. In the configuration diagram of FIG. 2, the clock generation unit 18, the recording processing unit 19, and the recording unit 20 are not used.
[0031]
Here, the layer discrimination for discriminating between the first recording layer 1b and the second recording layer 1c will be described in more detail with reference to FIGS.
FIG. 5 shows a case where the first recording layer 1b is recorded and reproduced. (A) shows a push-pull signal S1a output from the photodetector 5, (b) shows an inner-side prepit detection signal S2a, (C) is an outer peripheral prepit detection signal S3a, (d) is a bilateral prepit detection signal S4a, (e) is a binary wobble signal S5a, (f) is a prepit polarity detection signal S6a, (g) is Layer discrimination signals S7a, (h) indicate the pre-pit detection means S8a.
[0032]
FIG. 6 shows the case where the second recording layer 1c is recorded and reproduced. (A) shows the push-pull signal S1b output from the photodetector 5, (b) shows the inner-side prepit detection signal S2b, (C) is an outer peripheral prepit detection signal S3b, (d) is a bilateral prepit detection signal S4b, (e) is a binary wobble signal S5b, (f) is a prepit polarity detection signal S6b, (g) is Layer discrimination signals S7b, (h) indicate the pre-pit detection means S8b.
[0033]
First, the case of recording / reproducing the first recording layer 1b will be described with reference to FIGS.
Hereinafter, the case of recording / reproducing the groove G12 of the first recording layer 1b in FIG. 1 will be described.
The push-pull signal S1a output from the photodetector 5 is detected by the inner circumference side prepit detection signal 10 and the outer circumference side prepit detection signal 11. The push-pull signal S1a is obtained by superimposing the inner peripheral side prepit signal S12a and the outer peripheral side prepit signal S14a on the wobble signal S10a.
[0034]
As shown in FIG. 5 (a), in the first recording layer 1b, the land prepit L11 is at the peak position on the inner circumference side of the wobble of the groove G12, so that the inner circumference centered on the wobble signal S10a due to this wobble. A side pre-pit signal S12a is detected. On the other hand, since the land prepit L12 is also arranged at the disc outer peripheral peak position of the wobble of the groove G12, the outer peripheral prepit signal S14a by the land prepit L12 is detected. In the figure, the inner peripheral side pre-pit signal S12a is indicated by a solid line, and the outer peripheral side pre-pit signal S14a is indicated by a dotted line.
[0035]
The inner periphery side prepit signal S12a detected in this way is binarized by the inner periphery side slice level S11a corresponding to the polarity of the inner periphery side of the wobble signal S10a in the inner periphery side prepit detection means 10, and FIG. ) To detect the inner peripheral side pre-pit detection signal S2a. On the other hand, the outer peripheral side prepit detection means 11 binarizes the outer peripheral side prepit signal S14a with an outer peripheral side slice level S13a corresponding to the outer peripheral side polarity of the wobble signal S10a, and the outer peripheral side prepit detection signal as shown in FIG. S3a is detected.
[0036]
As shown in FIG. 5E, the wobble signal detection means 12 takes out the wobble signal S10a from the push-pull signal S1a detected from the output of the photodetector 5 using a bandpass filter (not shown), and binarizes it. The means 13 generates a binarized wobble signal S5a. The polarity of the binarized wobble signal S5a is positive when it is on the inner peripheral side when viewed from the amplitude center of the wobble signal S10a, and is negative when it is on the outer peripheral side.
[0037]
The detected inner peripheral prepit detection signal S2a, outer peripheral prepit detection signal S3a and binarized wobble signal S5a are input to the layer discrimination and prepit signal extraction means 14.
As shown in FIG. 5 (d), in the layer discrimination and prepit signal extraction means 14, the first logical sum 141 calculates the logical sum of the inner circumference side prepit detection signal S2a and the outer circumference side prepit detection signal S3a, and both side prepit detection signals. S4a is generated.
[0038]
Further, as shown in FIG. 5 (f), the second logical sum means 142 takes the logical sum of the both-side prepit detection signal S4a and the binarized wobble signal S5a to obtain the prepit polarity detection signal S6a. When the land pre-pit L11 is at the peak position on the inner circumference side of the groove G12, a positive pulse is output. As shown in FIG. 5G, the land pre-pit polarity detection signal S6a is subjected to peak hold processing by a peak hold circuit 143, thereby obtaining a layer discrimination signal S7a. When the land prepit L11 is at the peak position on the inner circumference side of the groove G12, a positive layer discrimination signal is output and it is discriminated that the land prepit L11 is in the first recording layer 1b.
[0039]
As shown in FIG. 5 (h), after determining that the first recording layer 1b is being recorded / reproduced, the layer determination and prepit signal extraction means 14 uses the selection circuit 144 as the prepit detection signal S8a as the inner peripheral side prepit. The detection signal S2a is selected. Then, it is output to the clock generation means 18, and the first recording layer 1b is recorded and reproduced by the same operation as described above.
[0040]
Next, the case of recording / reproducing the second recording layer 1c will be described with reference to FIGS.
Hereinafter, a case where the groove G22 of the second recording layer 1c in FIG. 1 is recorded and reproduced will be described.
When recording / reproducing the second recording layer 1c, as shown in FIG. 6 (a), the land pre-pit L22 is located at the peak position on the disk outer periphery side of the groove G22, so that the wobble signal S10b is the center. The outer peripheral pre-pit signal S14b is detected. In the figure, the outer peripheral prepit signal S14b is indicated by a solid line, and the inner peripheral prepit signal S12b is indicated by a dotted line.
[0041]
For the inner side prepit detection signal S2b, the outer side prepit detection signal S3b, the both side prepit detection signal S4b, and the binary wobble signal S5b shown in FIGS. 6A to 6E, FIG. Since this is the same, the description thereof is omitted.
Next, as shown in FIG. 6 (f), similarly to the case of FIG. 5 (f), the second logical sum means 142 takes the logical sum of the both-side pre-pit detection signal S4b and the binarized wobble signal S5b to pre-pit. A polarity detection signal S6b is obtained. When the land pre-pit L22 is at the peak position on the disk outer periphery side of the groove G22, the pre-pit polarity detection signal S6b is binarized by the double-side pre-pit detection signal S4b shown in FIG. 6 (d) shown in FIG. 6 (e). Since it is masked by the wobble signal S5b, it remains a negative value. Therefore, as shown in FIG. 6G, the layer discrimination signal S7a also takes a negative value.
[0042]
When the land pre-pit L22 is at the disk outer peripheral peak of the groove G22, a negative layer discrimination signal is output, and it is discriminated that the land prepit L22 is in the second recording layer 1c. Next, as shown in FIG. 6 (h), after determining that the second recording layer 1c is being recorded / reproduced, the layer determination and prepit signal extraction means 14 uses the selection circuit 144 as the prepit detection signal S8b. The outer peripheral pre-pit detection signal S3b is selected. Then, it is output to the clock generation means 18, and the second recording layer 1c is recorded and reproduced by the same operation as described above.
[0043]
Even when the focus is defocused from the first recording layer 1b to the second recording layer 1c or from the second recording layer 1c to the first recording layer 1b, the peak position on the inner circumference side of the groove G12 of the first recording layer 1b The inner side prepit signal S12a by the land prepit L11 arranged at the position or the outer side land prepit signal S12b by the land prepit L22 arranged at the disk outer circumference side peak position of the groove G22 of the second recording layer 1c is detected. By using the layer discrimination and pre-pit signal detection means 14 and the focus control means 15, the recording layer before defocusing can be quickly adjusted again.
[0044]
As described above, according to the optical disc of the embodiment of the present invention, in the optical disc having two recording layers, the land pre-pit L11 is provided on the first recording layer 1b at the peak position on the inner circumference side of the groove G12. In the second recording layer 1c, the land pre-pits L22 are arranged at the disk outer peripheral side peak position of the groove G22. Therefore, even when the focus is lost, the recording layer before focusing can be quickly refocused.
Further, according to the optical disc recording / reproducing apparatus of the embodiment of the present invention, when the optical disc 1 described above is used, since the layer discrimination / pre-pit signal extraction means 14 and the focus control means 15 are provided, defocusing occurs. Even in the event of a failure, it is possible to quickly refocus the recording layer before focusing.
[0045]
Here, the detection time can be shortened by using the prepit signals on both sides, but the same detection is possible by using only one of the inner peripheral side prepit signal and the outer peripheral side prepit signal.
In the above description, the auxiliary information is recorded in the land and the information recording signal is recorded in the groove, but the same effect can be obtained in the reverse case. The auxiliary information in this case is called groove preland. That is, the groove preland means a groove in which auxiliary information such as an address is recorded in advance.
[0046]
The layer discrimination signal S7 is generated by peak-holding the pre-pit polarity detection signal S6. However, instead of the peak-hold circuit 143, the pre-pit detection signal S6 may be latched with a wobble period. Further, if the same pre-pit polarity detection signal S6 continues for an arbitrary wobble period, the layer discrimination signal S7 can be determined to prevent detection errors.
[0047]
【The invention's effect】
According to the optical disc of the present invention, in the first recording layer and the second recording layer, the land pre-pit is either the disc inner peripheral peak position of the wobble or the disc outer peripheral peak position of the wobble. Since they are arranged on either of them, even when the focus is lost, it is possible to quickly refocus the recording layer before the focus.
Further, according to the optical disc recording / reproducing apparatus of the present invention, the land pre-pit detection signal or the outer side pre-pit detected from the land pre-pit or the groove pre-land arranged at the wobble disc inner or outer side peak position. Based on the detection signal and the binarized wobble signal of the wobble, the layer discrimination and pre-pit signal extraction means for outputting the layer discrimination signal, the layer discrimination signal and the layer indication signal for instructing the recording layer in advance are compared, and the result If the focus is different, it is determined that the focus has been lost, and the focus control means for performing the focus jump control so as to refocus the recording / playback layer before the focus is lost. But you can quickly refocus to the pre-focus recording layer.
[Brief description of the drawings]
FIG. 1 is an enlarged plan view of an optical disc according to an embodiment of the present invention.
FIG. 2 is a block diagram showing an optical disc recording / reproducing apparatus according to an embodiment of the present invention.
FIG. 3 is a block diagram showing layer discrimination and pre-pit signal extraction means used in an optical disc recording / reproducing apparatus.
FIG. 4 is a block diagram showing focus control means used in an optical disc recording / reproducing apparatus.
FIG. 5 is a diagram showing operation waveforms for explaining the operation of the first recording layer of the optical disc recording / reproducing apparatus in the embodiment of the present invention.
FIG. 6 is a diagram showing operation waveforms for explaining the operation of the second recording layer of the optical disc recording / reproducing apparatus in the embodiment of the present invention.
7A and 7B show a conventional optical disc having two recording layers, in which FIG. 7A is a cross-sectional view and FIG. 7B is a plan view in which the surface is enlarged.
FIG. 8 is a plan view showing each zone of the optical disc.
FIG. 9 is a diagram showing a configuration of a land pre-pit block.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical disk, 1b ... 1st recording layer (1st recording layer), 1c ... 2nd recording layer (2nd recording layer), 14 ... Layer discrimination | determination and prepit signal extraction means, 15 ... Focus control means

Claims (3)

A recording layer having a groove formed concentrically or spirally from the innermost periphery to the outermost periphery and a land portion continuously formed between the grooves is laminated in two layers, and the land portion Has an information recording part in which auxiliary information used when recording or reproducing information signals in the groove is recorded in advance as land prepits, and the information recording part is divided into a plurality of zones in advance in the disc radial direction. The groove is continuously wobbled at a constant frequency on both sides of the groove in the disk circumferential direction, and each of the plurality of zones in each of the two recording layers is adjacent in the disk radial direction. The phase of the wobble of the groove is always the same phase, and consists of a plurality of the land pre-pits arranged in the land portion for each period of the wobble. Between lands Li pit groups are adjacent in the radial direction of the disk is recorded in a position disk circumferential direction of the phase is different, the in the recording layer of the first layer on the disk inner circumference side peak position of the wobble Randopuri Pits are arranged, and the land pre-pits are arranged at the outer peripheral peak position of the wobble disc in the second recording layer, or the wobble disc in the first recording layer. An optical disc, wherein the land pre-pits are arranged at a peak position on the outer peripheral side, and the land pre-pits are arranged at a peak position on the inner peripheral side of the wobble disc in the second recording layer . A recording layer having a groove formed concentrically or spirally from the innermost circumference to the outermost circumference and a land portion continuously formed between the grooves is laminated in two layers. Has an information recording unit in which auxiliary information used when recording or reproducing an information signal on the land unit is recorded in advance as a groove preland, and the information recording unit is divided into a plurality of zones in advance in the disc radial direction. The land portion is continuously wobbled at a constant frequency on both sides of the land portion in the disc circumferential direction, and in each of the plurality of zones in each of the two recording layers, The phase of the wobbles of the adjacent land portions is always the same phase, and a plurality of the groove pre-lands arranged in the groove every period of the wobble That the grooves pre-land group is recorded at a position where the phase of the disk circumferential direction are different between the land portions adjacent in the radial direction of the disk, is the recording layer of the first layer wherein the disc inner circumference side peak position of the wobble A groove preland is disposed, and the groove preland is disposed in the second recording layer at the peak position of the wobble disc outer periphery, or the wobble is formed in the first recording layer. The groove preland is disposed at a peak position on the outer circumference side of the disk, and the groove preland is disposed at a peak position on the inner circumference side of the wobble in the second recording layer. optical disk. In the optical disk recording and reproducing apparatus for recording and reproducing according to claim 1 Symbol placement of the optical disc, the inner peripheral side pit detection signal or the outer peripheral side to be Randopuripi' bets or we detected disposed in the circumferential side or outer circumferential side peak position disk of the wobble From the pre-pit detection signal and the binarized wobble signal of the wobble, a layer discrimination and pre-pit signal extraction means for outputting a layer discrimination signal, the layer discrimination signal and a layer indication signal for instructing a recording layer in advance are compared, An optical disc recording comprising: focus control means for performing focus jump control so as to determine that the focus has been lost when the results are different, and to refocus the recording / reproduction layer before the focus is lost Playback device.

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