JP3908347B2 - Optical disc playback apparatus and optical disc playback method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical disc reproducing apparatus and an optical disc reproducing method for reproducing data recorded on an optical disc. In particular, the present invention relates to an optical disc reproducing apparatus and an optical disc reproducing method for reproducing header area data (signals having different DC levels).
[0002]
[Prior art]
In recent years, optical disks such as DVD-ROM and DVD-RAM have attracted attention as large-capacity information storage media. These optical disks are formed, for example, by coating a metal film layer such as tellurium or bismuth in a donut shape on the surface of a substrate formed in a circle with glass or plastics.
[0003]
These optical discs include, for example, a plurality of land tracks LT1 to LT3 formed of concentric or spiral lands (convex portions) and concentric or spiral grooves (concave portions) as shown in FIG. A plurality of formed groove tracks GT1 to GT3... Are provided.
[0004]
These land tracks LT1 to LT3 are provided with land recording areas LR1 to LR3 including a user data area in which user data is recorded. Similarly, groove recording areas GR1 to GR3... Including user data areas are also provided in the groove tracks GT1 to GT3. The configuration of these recording areas will be described in detail later.
[0005]
Address data of the land recording area LR1 in the land track LT1 is recorded on the extended line of the boundary between the land track LT1 and the groove track GT (not shown) adjacent to the land track LT1 and on the outer peripheral side of the land track LT1. A land header area LH1 is arranged. The land header area LH1 is composed of a header part H1 and a header part H2.
[0006]
On the extended line of the boundary between the groove track GT1 and the land track LT1 adjacent to the groove track GT1 and adjacent to the outer periphery of the groove track GT1, the address data of the groove recording area GR1 in the groove track GT1 is recorded. A header area GH1 is arranged. The header area GH1 is composed of a header part H3 and a header part H2.
[0007]
Similarly, a land header area LH2 in which address data of the land recording area LR2 and the like are recorded is arranged on an extended line at the boundary between the land track LT2 and the groove track GT1. On the extended line at the boundary between the groove track GT2 and the land track LT2, a groove header region GH2 in which address data of the groove recording region GR2 and the like are recorded is disposed. On the extended line at the boundary between the land track LT3 and the groove track GT2, a land header area LH3 in which address data of the land recording area LR3 is recorded is arranged. On the extended line at the boundary between the groove track GT3 and the land track LT3, a groove header region GH3 in which address data of the groove recording region GR3 and the like are recorded is disposed.
[0008]
Further, the land header areas LH1 to LH4 are arranged at the same position in the radial direction of the optical disc, and the groove header areas GH1 to GH3 are also arranged at the same position in the radial direction of the optical disc. In addition, the land header areas LH1 to LH4 and the groove header areas GH1 to GH3 are arranged at positions shifted from the track direction by the length of the address data area.
[0009]
Data recorded in the land header area LH and the groove header area GH arranged in this way is reproduced by a light beam that scans the land track RT or the groove track GT. In this case, the reproduction signal S is, for example, a signal as shown in FIG. The reproduction signal S includes a reproduction signal Sa reproduced from the land header area LH and a reproduction signal Sb reproduced from the groove header area GH. Further, due to the positional relationship between the land header region LH and the groove header region GH, the reproduction signal Sa and the reproduction signal Sb are signals having different DC levels. For this reason, the reproduction signal S is subjected to filtering processing by a high-pass filter, and a DC component is removed from the reproduction signal S. A binarization process is performed on the reproduction signal S subjected to the filtering process.
[0010]
[Problems to be solved by the invention]
In the filtering process described above, it is necessary to switch the cut-off frequency in accordance with each of the reproduction signal Sa and the reproduction signal Sb. In addition, if this cut-off frequency is not switched at high speed, there is a possibility that accurate binarization processing cannot be performed thereafter. However, if the cutoff frequency is simply switched at a high speed, the reproduction signal may be distorted and the reproduction margin may be cut, which may hinder accurate reproduction.
[0011]
An object of the present invention is made in view of the above circumstances, and an optical disc playback apparatus and an optical disc playback capable of accurately reproducing signals having different DC levels obtained from a land header area and a groove header area It is to provide a method.
[0012]
[Means for Solving the Problems]
In order to solve the above problems and achieve the object, an optical disk reproducing apparatus of the present invention is configured as follows.
The optical disk reproducing apparatus of the present invention has a plurality of tracks formed of concentric or spiral lands and grooves, and has a header area in which address data is recorded on an extension line of the boundary between these tracks. In an optical disk reproducing apparatus for reproducing data of an optical disk having a recording area in which user data associated with the address data is recorded, irradiation means for irradiating the optical disk to be reproduced with a light beam that scans in the track direction; The light receiving means for receiving the reflected light from the optical disk of the light beam emitted from the irradiating means and the light receiving when reproducing the data recorded on the optical disk reflected in the reflected light received by the light receiving means. DC component for removing a predetermined DC component from the signal obtained through the means When the reproduction means and the header area are reproduced, the cutoff frequency of the DC component removing means is set within a predetermined period after the input of the signal corresponding to the header area is started to the DC component removing means. And a switching means for switching to the frequency.
[0013]
The optical disk reproducing apparatus of the present invention has a plurality of tracks formed of concentric or spiral lands and grooves, and a header area in which address data is recorded following the synchronization code on an extension of the boundary between these tracks. In an optical disk reproducing apparatus for reproducing data of an optical disk having a recording area in which user data related to the address data is recorded in these tracks, a light beam that scans in the track direction is applied to the optical disk to be reproduced. Irradiating means for irradiating, light receiving means for receiving reflected light from the optical disk of the light beam emitted from the irradiating means, and reproducing data recorded on the optical disk reflected in the reflected light received by the light receiving means In doing so, a predetermined DC component is obtained from the signal obtained through the light receiving means. DC component removing means to be removed, and when reproducing the header area, it corresponds to a synchronization code provided in the header area after input of a signal corresponding to the header area is started to the DC component removing means Switching means for switching the cut-off frequency of the DC component removing means to a predetermined frequency before the signal input is completed.
[0014]
The optical disk reproducing apparatus of the present invention has a plurality of tracks formed of concentric or spiral lands and grooves, and a header area in which address data is recorded following the synchronization code on an extension of the boundary between these tracks. In an optical disk reproducing apparatus for reproducing data of an optical disk having a recording area in which user data related to the address data is recorded in these tracks, a light beam that scans in the track direction is applied to the optical disk to be reproduced. Irradiating means for irradiating, light receiving means for receiving reflected light from the optical disk of the light beam emitted from the irradiating means, and reproducing data recorded on the optical disk reflected in the reflected light received by the light receiving means In doing so, a predetermined DC component is obtained from the signal obtained through the light receiving means. DC component removing means to be removed, and when reproducing the header area, it corresponds to a synchronization code provided in the header area after input of a signal corresponding to the header area is started to the DC component removing means Switching signal supplying means for supplying a switching signal for switching the cut-off frequency of the DC component removing means to a frequency suitable for reproduction of the header area until the signal input is completed; It has.
[0015]
The optical disk reproducing apparatus of the present invention has a plurality of tracks formed of concentric or spiral lands and grooves, and has a header area in which address data is recorded on an extension line of the boundary between these tracks. In an optical disk reproducing apparatus for reproducing data of an optical disk having a recording area in which user data associated with the address data is recorded, irradiation means for irradiating the optical disk to be reproduced with a light beam that scans in the track direction; The light receiving means for receiving the reflected light from the optical disk of the light beam emitted from the irradiating means, and the light receiving when reproducing the data recorded on the optical disk reflected in the reflected light received by the light receiving means. DC component for removing a predetermined DC component from the signal obtained through the means Leaving means, a first header area provided on an extension of a boundary between a first track of the plurality of tracks and a second track adjacent to the first track, and the second track, When reproducing the second header area provided on the extension line of the boundary with the third track adjacent to the second track, the DC component removing means transmits a signal corresponding to the first header area. The cut-off frequency of the DC component removing means is switched to the first frequency within a predetermined period after the input is started, and the input of the signal corresponding to the second header area is started to the DC component removing means. Switching means for switching the cut-off frequency of the DC component removing means to the second frequency within a predetermined period.
[0016]
The optical disk reproducing apparatus of the present invention has a plurality of tracks formed of concentric or spiral lands and grooves, and a header area in which address data is recorded following the synchronization code on an extension of the boundary between these tracks. In an optical disk reproducing apparatus for reproducing data of an optical disk having a recording area in which user data related to the address data is recorded in these tracks, a light beam that scans in the track direction is applied to the optical disk to be reproduced. Irradiating means for irradiating, light receiving means for receiving reflected light from the optical disk of the light beam emitted from the irradiating means, and reproducing data recorded on the optical disk reflected in the reflected light received by the light receiving means In doing so, a predetermined DC component is obtained from the signal obtained through the light receiving means. DC component removing means for removing, a first header region provided on an extension of a boundary between a first track of the plurality of tracks and a second track adjacent to the first track, and When reproducing the second header area provided on the extended line of the boundary between the second track and the third track adjacent to the second track, the direct current component removing means is provided with the first header area. The cutoff frequency of the DC component removing means is switched to the first frequency from the start of input of the corresponding signal until the input of the signal corresponding to the synchronization code provided in the first header area is completed, The input of the signal corresponding to the second header area to the DC component removing means is started until the input of the signal corresponding to the synchronization code provided in the second header area is completed. And a switching means for switching the cutoff frequency of the component removing means to the second frequency.
[0017]
The optical disk reproducing apparatus of the present invention has a plurality of tracks formed of concentric or spiral lands and grooves, and a header area in which address data is recorded following the synchronization code on an extension of the boundary between these tracks. In an optical disk reproducing apparatus for reproducing data of an optical disk having a recording area in which user data related to the address data is recorded in these tracks, a light beam that scans in the track direction is applied to the optical disk to be reproduced. Irradiating means for irradiating, light receiving means for receiving reflected light from the optical disk of the light beam emitted from the irradiating means, and reproducing data recorded on the optical disk reflected in the reflected light received by the light receiving means In doing so, a predetermined DC component is obtained from the signal obtained through the light receiving means. DC component removing means for removing, a first header region provided on an extension of a boundary between a first track of the plurality of tracks and a second track adjacent to the first track, and When reproducing the second header area provided on the extended line of the boundary between the second track and the third track adjacent to the second track, the direct current component removing means is provided with the first header area. During the period from the start of the input of the corresponding signal to the completion of the input of the signal corresponding to the synchronization code provided in the first header area, the direct current component removing means is cut by the direct current component removing means. A first switching signal for switching the off-frequency to the first frequency is supplied, and a signal corresponding to the second header area is input to the DC component removing means, and then provided in the second header area. Until the input of the signal corresponding to the synchronization code is completed, the second switching signal for switching the cutoff frequency of the DC component removing means to the second frequency is supplied to the DC component removing means. Switching signal supply means.
[0018]
As a result of taking the above-mentioned means, the following effects occur.
According to the optical disk reproducing apparatus of the present invention, the area (VFO area) in which the synchronization code of the header area is recorded after the input of the signal corresponding to the header area is started to the DC component removing means (high-pass filter). The cutoff frequency of the DC component removing means (high-pass filter) is switched at high speed until the input of the signal corresponding to) is completed. Thereby, it is possible to satisfactorily reproduce the address data after the header area.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 3 is a diagram showing a state where the data recording area of the optical disk is divided into a plurality of zones, and FIG. 4 is a diagram showing the data structure of the data recording area of the optical disk.
[0020]
As shown in FIGS. 3 and 4, the data recording area of the optical disk 1 is large and can be divided into a lead-in area 2, a data area 3, and a lead-out area 4. Each area is composed of a plurality of zones, and each zone is composed of a plurality of tracks as described above.
[0021]
The lead-in area 2 includes an embossed data zone 5 and a rewritable data zone 6. In the emboss data zone 5, reference signals and control data are recorded at the time of manufacture. The rewritable data zone 6 further includes a guard track zone, a disk test zone, a drive test zone, a disk identification data zone, a replacement management zone as a replacement management area, and the like. .
[0022]
The data area 3 is composed of a plurality of zones, for example, zones 3a,... 3x.
The lead-out area 4 is a rewritable data zone similar to the rewritable data zone 6 formed in the lead-in area 2. In the lead-out area 4, data having the same recording contents as the data zone 6 is recorded.
[0023]
In addition, the optical disk 1 of this embodiment has a different number of sectors per track on the inner circumference side and the outer circumference side. That is, the number of sectors in the outer track is larger than the number of sectors in the inner track. Therefore, as shown in FIG. 5, the rotation speed (rotation speed) of the optical disk 1 changes for each zone. Therefore, in each zone in the lead-in area 2, each zone in the data area 3, and each zone in the lead-out area 4, the rotation speed decreases as it goes from the inner circumference side to the outer circumference side of the optical disc 1. The relationship between the rotational speed data and the number of sectors per track (FIG. 5) for each zone is recorded in a table 10a of the memory 10 described later.
[0024]
As shown in FIGS. 3 and 4, the tracks in the zones 3a,..., 3x of the data area 3 are preliminarily stored in each ECC (error correction code) block data unit (for example, 38688 bytes) as a data recording unit. Is recorded.
[0025]
Next, a schematic configuration of the sector area will be described with reference to FIG. FIG. 6 is a diagram showing a schematic configuration of the sector area.
As shown in FIG. 6, one sector is composed of approximately 2697 bytes. The breakdown includes a 128-byte header area, a 2-byte mirror area, and a 2567-byte recording area. The header area is a portion recorded (preformatted) as an uneven shape before shipment. The channel bits recorded in the sector area (excluding an address mark AM area to be described later) are in the form of 8-16 code modulation of 8-bit data into 16-bit channel bits.
[0026]
In the header area, predetermined data is recorded when the optical disc 1 is manufactured. This header area is composed of four areas (H1 to H4 shown in FIG. 1), that is, a header 1 area, a header 2 area, a header 3 area, and a header 4 area. The header 1 area and the header 3 area are 46 bytes, and the header 2 area and the header 4 area are 18 bytes.
[0027]
The header 1 area and the header 3 area are a 36-byte synchronous code VFO (Variable Frequency Oscillator) 1 area, a 3-byte address mark AM (Address Mark) area, a 4-byte address PID (Physical ID) area, and a 2-byte error detection. Code IED (ID Error Detection Code) area and 1 byte postamble PA (Post Ambles) area. On the other hand, the header 2 area and the header 4 area are an 8-byte synchronization code VFO2 area, a 3-byte address mark AM area, a 4-byte address PID area, a 2-byte error detection code IED area, and a 1-byte postamble PA area. It is comprised by.
[0028]
Address information is recorded in the PID area. More specifically, 1-byte sector information (including a PID number) and 3-byte sector number are recorded.
[0029]
In the synchronization code VFO1 area and VFO2 area, a continuous repetitive pattern (100010001000...) For pulling in a PLL (Phase Locked Loop) is recorded. More specifically, the pattern recorded in the VFO area is for frequency synchronization for reproducing the address information recorded in the PID area.
[0030]
An address mark is recorded in the AM area, and this address mark plays a role of detecting a block boundary when demodulating the fixed-length block code. More specifically, the address mark recorded in the AM area indicates the position of the address information recorded in the PID area. For the address mark recorded in the AM area, a special pattern that does not appear elsewhere is used.
[0031]
In the error detection code IED area, an error (error) detection code for a sector address (including an ID number) is recorded, and the presence or absence of an error in the PID read by this error detection code is detected.
[0032]
State information necessary for demodulation is recorded in the postamble PA1 area and PA2 area, and also has a role of polarity adjustment so that the header area ends with a space. The mirror area is used for offset correction of a tracking error signal, generation of timing of a land / groove switching signal, and the like.
[0033]
The recording area includes a (10 + J / 16) byte gap area, a (20 + K) byte guard 1 area, a 35 byte VFO 3 area, a 3 byte PS (pre-synchronous code) area, and a 2418 byte data area (user data area). 1) a postamble PA3 area of 1 byte, a guard 2 area of (55-K) bytes, and a buffer area of (25-J / 16) bytes. Incidentally, J is an integer of 0 to 15 and K is an integer of 0 to 7 and takes a random value.
[0034]
The gap area is an area where nothing is recorded.
The guard 1 area is an area provided in order to prevent the terminal degradation during the repeated recording unique to the phase change recording medium from reaching the VFO3 area.
[0035]
The VFO3 area is also an area for PLL lock, but it is also an area intended to synchronize byte boundaries by inserting a synchronization code into the same pattern.
The PS area is a tuning area for connecting to the data area.
[0036]
The data area is an area composed of a data ID, a data ID error correction code IED (Data ID Error Detection Code), a synchronization code, an ECC (Error Collection Code), an EDC (Error Detection Code), user data, and the like. The data ID is sector ID1 to ID16 having a 4-byte (32 channel bit) configuration of each sector. The data ID error correction code IED is an error correction code having a 2-byte (16 bits) configuration for data ID.
[0037]
The postamble PA3 area includes state information necessary for demodulation, and indicates the end of the last byte of the previous data area.
The guard 2 area is an area provided in order to prevent the terminal degradation at the time of repeated recording unique to the phase change recording medium from reaching the data area.
[0038]
The buffer area is an area provided to absorb rotational fluctuations of a motor that rotates the optical disc 1 so that the data area does not cover the next header area. Next, a schematic configuration of an optical disk reproducing apparatus that reproduces data recorded on the above-described optical disk will be described. FIG. 7 is a diagram showing a schematic configuration of an optical disc reproducing apparatus according to an embodiment of the present invention. This optical disk reproducing apparatus irradiates a focused light beam to the optical disk 1 to receive the reflected light of the light beam from the optical disk 1 and records it on the optical disk 1 reflected in the received reflected light. Data is played back.
[0039]
As shown in FIG. 7, the optical disc 1 is loaded on the spindle motor 23 while being held by the cartridge 21. The optical disc 1 is rotated by the spindle motor 23 at, for example, a different rotational speed for each zone. The spindle motor 23 is controlled by a motor control circuit 24.
[0040]
Data recorded on the optical disc 1 is reproduced by the optical head 25. As will be described later, the spindle motor 23 and the optical head 25 are provided on a fixed base.
[0041]
The optical head 25 is fixed to a drive coil 27 that constitutes a movable portion of the linear motor 26, and the drive coil 27 is connected to a linear motor control circuit 28.
[0042]
On the other hand, a speed detector 29 is connected to the linear motor control circuit 28 that drives the linear motor 26, and the speed signal of the optical head 25 detected by the speed detector 29 is sent to the linear motor control circuit 28. The moving speed of the optical head 25 is controlled.
[0043]
An objective lens 30 is provided on the carriage 70 of the optical head 25 and is supported by a wire or a leaf spring (not shown). The objective lens 30 is moved in the focusing direction (the optical axis direction of the lens) by the drive coil 31, and is moved in the tracking direction (the direction orthogonal to the optical axis of the lens) by the drive coil 32.
[0044]
Further, a semiconductor laser 39 as an irradiation means for irradiating a light beam is driven by a laser driving circuit 35 to generate a laser beam. The laser drive circuit 35 corrects the light amount of the laser beam generated by the semiconductor laser 39 in accordance with the monitor current from the monitoring photodiode PD of the semiconductor laser 39.
[0045]
The laser drive circuit 35 operates in synchronization with a clock signal for data recording or data reproduction from a PLL circuit (not shown). The PLL circuit divides a basic clock signal from an oscillator (not shown) to generate a clock signal for data recording or data reproduction. In the laser drive circuit 35, when a laser beam for data recording is generated from the semiconductor laser 39, control is performed so as to generate a high-power laser beam that is higher by a predetermined level than the laser beam for data reproduction.
[0046]
The laser beam generated by the semiconductor laser 39 driven by the laser driving circuit 35 is collimated by the collimator lens 40, and then the optical path is bent at a substantially right angle by the half prism 41. That is, the laser beam generated from the semiconductor laser 39 by the half prism 41 is irradiated toward the optical disc 1 in a collimated state. This laser beam is focused on the data recording surface of the optical disc 1 by the objective lens 30.
[0047]
Then, the reflected light beam from the data recording surface of the optical disc 1 passes through the objective lens 30 and the half prism 41, and passes through the condenser lens 42 and the cylindrical lens 43 to the photodetector 44 as a light receiving means. Led.
[0048]
The photodetector 44 is constituted by, for example, four-divided photodetector cells 44a, 44b, 44c, and 44d.
The output signal of the light detection cell 44a included in the light detector 44 is supplied to one end of the adder 46a via the amplifier 45a, and the output signal of the light detection cell 44b is supplied to one end of the adder 46b via the amplifier 45b. To be supplied. The output signal of the photodetection cell 44c is supplied to the other end of the adder 46a via the amplifier 45c, and the output signal of the photodetection cell 44d is supplied to the other end of the adder 46b via the amplifier 45d. .
[0049]
The output signal of the photodetection cell 44a included in the photodetector 44 is supplied to one end of the adder 46c via the amplifier 45a, and the output signal of the photodetection cell 44b is added to the adder 46d via the amplifier 45b. Is supplied to one end. The output signal of the photodetection cell 44c is supplied to the other end of the adder 46d via the amplifier 45c, and the output signal of the photodetection cell 44d is supplied to the other end of the adder 46c via the amplifier 45d. .
[0050]
The output signal of the adder 46a is supplied to the inverting input terminal of the differential amplifier OP2, and the output signal of the adder 46b is supplied to the non-inverting input terminal of the differential amplifier OP2. Accordingly, the differential amplifier OP2 supplies a signal related to the focus point, that is, a focus error signal, to the focusing control circuit 47 in accordance with the difference between the adders 46a and 46b. An output signal from the focusing control circuit 47 is supplied to the drive coil 31 and controlled so that the laser beam is always in a just focus on the data recording surface of the optical disc 1.
[0051]
The output signal of the adder 46c is supplied to the inverting input terminal of the differential amplifier OP1, and the output signal of the adder 46d is supplied to the non-inverting input terminal of the differential amplifier OP1. Thus, the differential amplifier OP1 supplies a tracking error signal to the tracking control circuit 48 according to the difference between the adders 46c and 46d. The tracking control circuit 48 creates a track drive signal according to the tracking error signal supplied from the differential amplifier OP1.
[0052]
The track drive signal output from the tracking control circuit 48 is supplied to the drive coil 32 in the tracking direction. The tracking error signal used in the tracking control circuit 48 is also supplied to the linear motor control circuit 28.
[0053]
The sum signal of the outputs of the light detection cells 44a to 44d of the light detector 44 in a state where the focusing control and the tracking control are performed in this way, that is, the output signals from the adders 46c and 46d are added by the adder 46e. The signal reflects changes in reflectance from pits formed on the track, that is, recorded data. This signal is supplied to the data reproduction circuit 38, and the data recorded on the data recording surface of the optical disk is reproduced in the data reproduction circuit 38.
[0054]
The reproduction data reproduced by the data reproduction circuit 38 is subjected to error correction by the error correction circuit 52 using the assigned error correction code ECC, and then the optical disk control device 56 as an external device via the interface circuit 55. Is output.
[0055]
A data generation circuit 34 is provided in the previous stage of the laser drive circuit 35. The data generation circuit 34 converts ECC block format data as recording data supplied from the error correction circuit 52 into recording ECC block format data to which a synchronization code for ECC block is added. A generation circuit 34a and a modulation circuit 34b that modulates recording data from the ECC block data generation circuit 34a by an 8-16 code conversion method are provided.
[0056]
The data generation circuit 34 is supplied with the record data to which the error correction code is given by the error correction circuit 52 and the error check dummy data read from the memory 10. The error correction circuit 52 is supplied with recording data from an optical disk control device 56 as an external device via an interface circuit 55 and a bus 49.
[0057]
The error correction circuit 52 assigns error correction codes (ECC1, ECC2) in the horizontal direction and the vertical direction to the recording data in units of 4 Kbytes for the recording data of 32 Kbytes supplied from the optical disk control device 56. , A sector ID (logical address number) is assigned, and ECC block format data is generated.
[0058]
Further, in this optical disc apparatus, a D / D used to exchange information between the focusing control circuit 47, the tracking control circuit 48, the linear motor control circuit 28, and the CPU 50 that controls the entire optical disc apparatus. An A converter 51 is provided.
[0059]
The motor control circuit 24, linear motor control circuit 28, laser drive circuit 35, data reproduction circuit 38, focusing control circuit 47, tracking control circuit 48, error correction circuit 53, etc. are controlled by the CPU 50 via the bus 49. The CPU 50 performs a predetermined operation according to a control program recorded in the memory 10.
[0060]
The memory 10 stores a control program and is used for data recording. This memory 10 has a table 10a in which the relationship between speed data (number of rotations) and the number of sectors per track is recorded for each zone.
[0061]
Next, a schematic configuration of the data reproduction circuit 38 will be described with reference to FIG. FIG. 8 is a diagram showing a schematic configuration of the data reproduction circuit 38.
As shown in FIG. 8, the data reproduction circuit 38 includes a high-pass filter 102, a comparator 104, a binarization circuit 106, a PLL circuit 108, a controller 120, a demodulation circuit 122, a header detection signal generation circuit 124, and the like.
[0062]
Here, the operation of the data reproduction circuit 38 will be described on the assumption that the land header area LH1 and the groove header area GH1 in FIG. 1 are reproduced. A reproduction signal S1 obtained by reproducing the land header area LH1 and the groove header area GH1 is a signal as shown in FIG. The reproduction signal S1 includes a reproduction signal S1a reproduced from the land header area LH1 and a reproduction signal S1b reproduced from the groove header area GH1. The reproduction signal S1a * is a part corresponding to the VFO1 area included in the land header area LH1, and the reproduction signal S2b * is a part corresponding to the VFO1 area included in the groove header area GH1. Note that, due to the positional relationship between the land header region LH1 and the groove header region GH1, the reproduction signal S1a and the reproduction signal S1b are signals having different DC levels.
[0063]
Such a reproduction signal S1 is output from the adder 46 shown in FIG. 7 and supplied to the high-pass filter 102 serving as a DC component removing unit. The cut-off frequency of the high-pass filter 102 is switched by a switching signal S3 supplied from the controller 120 serving as switching means (or switching signal supply means). That is, the cutoff frequency is switched to a predetermined frequency (first frequency or second frequency) in accordance with each of the reproduction signal S1a and the reproduction signal S1b.
[0064]
The controller 120 is a period during which the reproduction signal S1a * corresponding to the VFO1 area included in the land header area LH1 is output based on the header detection signal supplied from the outside and the clock output from the PLL circuit. A switching signal S3a is output. Further, the controller 120 outputs the reproduction signal S1b * corresponding to the VFO1 area included in the groove header area GH1 based on the header detection signal supplied from the outside and the clock output from the PLL circuit. During the period, the switching signal S3b is output.
[0065]
Thus, during the period when the reproduction signal S1a * or S1b * corresponding to the VFO1 region is being output, the switching signal S3a (first switching signal) or S3b (second switching signal) is output, The cut-off frequency of the high-pass filter is switched at high speed within the period. In the VFO area, a continuous repeating pattern for pulling in the PLL is recorded. Therefore, even if some distortion occurs in the reproduction signal S1a * or S1b * in the VFO region due to the high-speed filter switching of the high-pass filter, the substantial reproduction processing is not greatly affected. Therefore, the direct current obtained from the land header region LH1 and the groove header region GH1 can be obtained by switching the cut-off frequency of the high-pass filter at high speed during the period in which the reproduction signal S1a * or S2b * corresponding to the VFO region is output. It is possible to accurately reproduce signals having different levels.
[0066]
The reproduction signal S1 becomes the reproduction signal S2 from which the DC component has been removed by the high-pass filter 102 whose switching of the cutoff frequency is controlled by the switching signal S3. Thereafter, the reproduction signal S2 is supplied to the binarization circuit 106 via the comparator 104 and binarized. Further, the binarized signal is supplied to the demodulation circuit 112 via the PLL circuit 108 and demodulated. The header detection signal generation circuit 114 outputs a header detection signal based on the signal obtained from the demodulation circuit 112. The header detection signal output from the header detection signal generation circuit 114 is supplied to the PLL circuit 108.
[0067]
【The invention's effect】
According to the present invention, it is possible to provide an optical disc reproducing apparatus and an optical disc reproducing method capable of accurately reproducing signals having different DC levels obtained from the land header region and the groove header region.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining an example of an arrangement of land tracks formed by lands, groove tracks formed by grooves, and headers;
FIG. 2 is a diagram showing a reproduction signal S obtained from a land header area and a groove header area.
FIG. 3 is a diagram showing a state where a data recording area of an optical disc is divided into a plurality of zones.
FIG. 4 is a diagram showing a data structure of a data recording area of an optical disc.
FIG. 5 is a diagram showing a rotational speed corresponding to each zone of the optical disc and the number of sectors in a track of each zone.
FIG. 6 is a diagram showing a schematic configuration of a sector area.
FIG. 7 is a diagram showing a schematic configuration of an optical disc reproducing apparatus that reproduces data recorded on an optical disc.
FIG. 8 is a diagram showing a schematic configuration of a data reproduction circuit.
FIG. 9 shows a reproduction signal S1 input to the data reproduction circuit, a reproduction signal S2 output from the high-pass filter, and a switching signal S3 for controlling switching of the cutoff frequency of the high-pass filter supplied from the controller to the high-pass filter. FIG.
[Explanation of symbols]
LT1, LT2, LT3 ... Land track
GT1, GT2, GT3 ... groove track
LR1, LR2, LR3 ... land recording area
GR1, GR2, GR3 ... groove recording area
LH1, LH2, LH3 ... Land header area
GH1, GH2, GH3 ... groove header area
1 ... Optical disc
25. Optical head
38. Data reproduction circuit
102 ... High-pass filter
104 ... Comparator
106: Binarization circuit
108 ... PLL circuit
110 ... Controller
112 ... Demodulation circuit
114. Header detection signal generation circuit

Claims (6)

It has a plurality of tracks formed of concentric or spiral lands and grooves, and has a land header area and a groove header area in which address data is recorded following the synchronization code on the extended line of the boundary between these tracks , The land header area has first and second header portions in order from the top, and a first synchronization code having a first number of bytes is recorded at the top of the first header portion, and the second header A second synchronization code having a second number of bytes less than the first number of bytes is recorded at the beginning of the part, the groove header area has third and fourth header parts in order from the top, and The first synchronization code of the first number of bytes is recorded at the beginning of the header portion of 3, and the second synchronization code of the second number of bytes is recorded at the beginning of the fourth header portion, In the optical disk reproducing apparatus for reproducing data of an optical disc having a recording area where user data is recorded pending before the address data into serial track,
Irradiating means for irradiating the optical disc to be reproduced with a light beam that scans in the track direction;
A light receiving means for receiving reflected light from the optical disk of the light beam emitted from the irradiation means;
DC component removing means for removing a predetermined direct current component from the signal obtained through the light receiving means when reproducing the data recorded on the optical disk reflected in the reflected light received by the light receiving means,
When reproducing the land header area and the groove header area , input of a signal corresponding to the first synchronization code of the first header portion of the land header area to the DC component removing unit is started. Until input of a signal corresponding to the first synchronization code of the first header portion is completed and input of a signal corresponding to the first synchronization code of the third header portion of the groove header region and switching means but from being started until the input of the signal corresponding to the first synchronization code of said third header portion is completed, switching the cut-off frequency of the DC component removing means to a predetermined frequency,
An optical disc reproducing apparatus comprising: It has a plurality of tracks formed of concentric or spiral lands and grooves, and has a land header area and a groove header area in which address data is recorded following the synchronization code on the extended line of the boundary between these tracks , The land header area has first and second header portions in order from the top, and a first synchronization code having a first number of bytes is recorded at the top of the first header portion, and the second header A second synchronization code having a second number of bytes less than the first number of bytes is recorded at the beginning of the part, the groove header area has third and fourth header parts in order from the top, and The first synchronization code of the first number of bytes is recorded at the beginning of the header portion of 3, and the second synchronization code of the second number of bytes is recorded at the beginning of the fourth header portion, In the optical disk reproducing apparatus for reproducing data of an optical disc having a recording area where user data is recorded pending before the address data into serial track,
Irradiating means for irradiating the optical disc to be reproduced with a light beam that scans in the track direction;
A light receiving means for receiving reflected light from the optical disk of the light beam emitted from the irradiation means;
DC component removing means for removing a predetermined direct current component from the signal obtained through the light receiving means when reproducing the data recorded on the optical disk reflected in the reflected light received by the light receiving means,
When reproducing the land header area and the groove header area , input of a signal corresponding to the first synchronization code of the first header portion of the land header area to the DC component removing unit is started. from said first header portion to a first input of a signal corresponding to the synchronization code is completed, and a signal corresponding to the first synchronization code of said third header portion of the groove header region The cut-off frequency of the DC component removing means is set to the DC component removing means from the start of input until the input of the signal corresponding to the first synchronization code of the third header portion is completed. Switching signal supply means for supplying a switching signal for switching to a frequency suitable for reproduction of the land header and the groove header region;
An optical disc reproducing apparatus comprising: It has a plurality of tracks formed of concentric or spiral lands and grooves, and has a land header area and a groove header area in which address data is recorded following the synchronization code on the extended line of the boundary between these tracks , The land header area has first and second header portions in order from the top, and a first synchronization code having a first number of bytes is recorded at the top of the first header portion, and the second header A second synchronization code having a second number of bytes less than the first number of bytes is recorded at the beginning of the part, the groove header area has third and fourth header parts in order from the top, and The first synchronization code of the first number of bytes is recorded at the beginning of the header portion of 3, and the second synchronization code of the second number of bytes is recorded at the beginning of the fourth header portion, In the optical disk reproducing apparatus for reproducing data of an optical disc having a recording area where user data is recorded pending before the address data into serial track,
Irradiating means for irradiating the optical disc to be reproduced with a light beam that scans in the track direction;
A light receiving means for receiving reflected light from the optical disk of the light beam emitted from the irradiation means;
DC component removing means for removing a predetermined direct current component from the signal obtained through the light receiving means when reproducing the data recorded on the optical disk reflected in the reflected light received by the light receiving means,
When reproducing the land header area and the groove header area , input of a signal corresponding to the first synchronization code of the first header portion of the land header area to the DC component removing unit is started. Until the input of the signal corresponding to the first synchronization code of the first header portion is completed, the cut-off frequency of the DC component removing means is switched to the first frequency, and the third of the groove header area The DC component removing means from the start of the input of the signal corresponding to the first synchronization code of the header portion to the completion of the input of the signal corresponding to the first synchronization code of the third header portion Switching means for switching the cut-off frequency to the second frequency;
An optical disc reproducing apparatus comprising: It has a plurality of tracks formed of concentric or spiral lands and grooves, and has a land header area and a groove header area in which address data is recorded following the synchronization code on the extended line of the boundary between these tracks , The land header area has first and second header portions in order from the top, and a first synchronization code having a first number of bytes is recorded at the top of the first header portion, and the second header A second synchronization code having a second number of bytes less than the first number of bytes is recorded at the beginning of the part, the groove header area has third and fourth header parts in order from the top, and The first synchronization code of the first number of bytes is recorded at the beginning of the header portion of 3, and the second synchronization code of the second number of bytes is recorded at the beginning of the fourth header portion, In the optical disk reproducing apparatus for reproducing data of an optical disc having a recording area where user data is recorded pending before the address data into serial track,
Irradiating means for irradiating the optical disc to be reproduced with a light beam that scans in the track direction;
A light receiving means for receiving reflected light from the optical disk of the light beam emitted from the irradiation means;
DC component removing means for removing a predetermined direct current component from the signal obtained through the light receiving means when reproducing the data recorded on the optical disk reflected in the reflected light received by the light receiving means,
When reproducing the land header area and the groove header area , input of a signal corresponding to the first synchronization code of the first header portion of the land header area to the DC component removing unit is started. To supply a first switching signal for switching the cutoff frequency of the DC component removing means to the first frequency until the input of the signal corresponding to the first synchronization code of the first header portion is completed. And the input of the signal corresponding to the first synchronization code of the third header portion after the input of the signal corresponding to the first synchronization code of the third header portion of the groove header region is started. Switching signal supply means for supplying a second switching signal for switching the cut-off frequency of the DC component removing means to the second frequency before completion of
An optical disc reproducing apparatus comprising: It has a plurality of tracks formed of concentric or spiral lands and grooves, and has a land header area and a groove header area in which address data is recorded following the synchronization code on the extended line of the boundary between these tracks , The land header area has first and second header portions in order from the top, and a first synchronization code having a first number of bytes is recorded at the top of the first header portion, and the second header A second synchronization code having a second number of bytes less than the first number of bytes is recorded at the beginning of the part, the groove header area has third and fourth header parts in order from the top, and The first synchronization code of the first number of bytes is recorded at the beginning of the header portion of 3, and the second synchronization code of the second number of bytes is recorded at the beginning of the fourth header portion, In the optical disk reproducing method for reproducing data of an optical disc having a recording area where user data is recorded pending before the address data into serial track,
Irradiate the optical disk to be reproduced with a light beam that scans in the track direction,
The reflected light from the optical disk of the irradiated light beam is received,
When reproducing the land header area and the groove header area , the first synchronization code of the first header portion of the land header area is applied to the DC component removing means for removing the DC component contained in the signal. The cut-off frequency of the DC component removing means is switched to the first frequency after the input of the corresponding signal is started until the input of the signal corresponding to the first synchronization code of the first header portion is completed. The input of the signal corresponding to the first synchronization code of the third header portion after the input of the signal corresponding to the first synchronization code of the third header portion of the groove header region is started. Switching the cut-off frequency of the DC component removing means to the second frequency until the completion;
An optical disc reproducing method characterized by the above. It has a plurality of tracks formed of concentric or spiral lands and grooves, and has a land header area and a groove header area in which address data is recorded following the synchronization code on the extended line of the boundary between these tracks , The land header area has first and second header portions in order from the top, and a first synchronization code having a first number of bytes is recorded at the top of the first header portion, and the second header A second synchronization code having a second number of bytes less than the first number of bytes is recorded at the beginning of the part, the groove header area has third and fourth header parts in order from the top, and The first synchronization code of the first number of bytes is recorded at the beginning of the header portion of 3, and the second synchronization code of the second number of bytes is recorded at the beginning of the fourth header portion, In the optical disk reproducing method for reproducing data of an optical disc having a recording area where user data is recorded pending before the address data into serial track,
Irradiate the optical disk to be reproduced with a light beam that scans in the track direction,
The reflected light from the optical disk of the irradiated light beam is received,
When reproducing the land header area and the groove header area , the first synchronization code of the first header portion of the land header area is applied to the DC component removing means for removing the DC component contained in the signal. The cutoff frequency of the DC component removing means is switched to the first frequency after the input of the corresponding signal is started until the input of the signal corresponding to the first synchronization code of the first header portion is completed. A first switching signal is supplied to the third header portion, and input of a signal corresponding to the first synchronization code of the third header portion of the groove header region is started. Supplying a second switching signal for switching the cut-off frequency of the DC component removing means to the second frequency until the input of a signal corresponding to one synchronization code is completed;
An optical disc reproducing method characterized by the above.

Images