JP3014742B2 - Rewritable recording medium and recording / reproducing apparatus therefor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a recordable rewritable (including write-once) recording medium having a pre-group and a recording / reproducing apparatus therefor.

BACKGROUND ART A rewritable recording medium having a pregroove bent to carry track identification information including a track number is known.

When recording information on a track of such a rewritable recording medium or reading the recorded information, it is necessary to identify the track number. In the conventional rewritable recording medium, the same groove is recorded with the same track number. Then, the information to be rewritten is recorded in the pre-groove.

However, when information is recorded in the pre-groove, the flatness at the bottom of the pre-groove is poor, so that noise is mixed into the recorded information, and the C / N of the reproduced information signal is poor.

Therefore, it is conceivable to improve C / N by recording information to be recorded not on the pre-groove but on a land portion having good flatness sandwiched between the pre-grooves.

However, when recording on the land, the track number is identified from the pregrooves on both sides of the land.
Reading two different track numbers at the same time causes a new problem.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rewritable recording medium capable of identifying a correct track number even if information is recorded on a land portion of a rewritable recording medium having a pre-groove carrying track identification information including a track number. An object of the present invention is to provide a recording and reproducing device.

Configuration of the Invention A rewritable recording medium according to the present invention has one unit information section.
A rewritable recording medium having a pregroove bent to carry an address identification number, and a land portion as a recording track, wherein the address identification signal includes an odd track number area and an even track number area adjacent thereto. An odd track number is inserted in the odd track number region in the pregroove sandwiching the land portion serving as the odd track, and an even track number is inserted in the even track region in the pregroove sandwiching the land portion serving as the even track. It is a configuration that has.

The recording / reproducing apparatus according to the present invention is a recording / reproducing apparatus for the recording medium, wherein a read spot is projected on the land portion, and the reflected beam is received by at least two light receiving elements juxtaposed in a track crossing direction. An optical system for obtaining two optical conversion outputs of the light receiving element, and when the track numbers in the two optical conversion outputs match each other,
And an extraction unit that uses the track number as the current track number.

In the rewritable recording medium and the recording / reproducing apparatus for the same according to the present invention, the bent pre-groove has an odd-numbered track number area and an even-numbered track number area adjacent thereto, and sandwiches a land portion serving as an odd-numbered track. The odd-numbered track number is recorded in the odd-numbered track number area, and the even-numbered track number is recorded in the even-numbered track number area of the pre-groove sandwiching the land to be the even numbered track. And
During the period in which the writing or reading operation is being performed on the odd-numbered track, the odd-numbered track number in the odd-numbered track area is fetched. It takes in the track number.

Embodiment Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. 1 to FIG.

In FIG. 1, a pre-groove 2 is provided on a recording surface of a rewritable optical disc 1 as a rewritable recording medium. The information signal is recorded while the pits 4 are formed by irradiating a laser beam (not shown) with the land 3 sandwiched between the pre-grooves 2 as a recording track. The pits 4 are recorded in the form of a reversal of the magnetization direction in the case of a magneto-optical disk.

The wall surface 5 of the pregroove 2 is bent in a direction perpendicular to the track. Therefore, an address identification signal, which is a wobble signal of a high frequency component, is superimposed on the tracking error signal, which is a low frequency component, by this bent shape.
This address identification signal is formed in a predetermined format in a unit information signal section called a sector.

As shown in FIG. 2, one sector has a 137-bit configuration. One track is divided into 25 sectors,
This is because when a video format signal is recorded on the disk 1, it can be shared by NTSC and PAL.

FIG. 2 shows a data arrangement format of a sector including a track number of the 25 sectors. In this format, a clock pulse train CP of 52 bits (6.5 bytes) has a clock pulse train of one clock per bit. Is recorded, and becomes a PLL signal of a rotary servo at the time of recording or reproduction of the disk 1. Similarly, the area BS
Is a 3-bit block synchronization signal, and SN is a 5-bit sector number (0 to 24). The areas GP of 61 to 63, 98 to 100 and 135 to 137 bits are gaps, which are non-signal areas or irregular waveform areas.

The 18-bit area OTN of 64 to 81 is an odd track number area and bears an odd track number. Also, 119
The 18-bit area ETN of ~ 134 is an even-numbered track area, in which an even-numbered track number is recorded. Error detection code pulses are recorded in the two redundant bit areas CRC.

In FIG. 3, a track number (hereinafter, abbreviated as “1”) is recorded in a pre-groove area OTN on both sides of track 1, a track number is not recorded in one pre-groove area ETN, and the other is recorded. “2” is recorded in the pregroove. As for the track 2, "1" is recorded in one pre-groove area OTN adjacent to the track 1, as described above, and "3" is recorded in the other pre-groove. Further, in the area ETN, “2” is recorded in both pregrooves on both sides.

Thus, the odd track [2n-1] (n is a natural number).
The same track number is recorded in the pre-groove area OTN on both sides, and the correct track number of the even-numbered track [2n] is recorded in the pre-groove area ETN on both sides.

In FIG. 4, the spot 30 of the laser beam applied to the land 3 is larger than the width of the land. The reflected beam from the spot 30 is applied to the four-divided light receiving element 31 shown in FIG. The sum of the outputs of the four-divided light receiving element 31 becomes a read signal in the reproduction mode, and the two sum signals are supplied to the differential amplifier 32. The output of the operation amplifier 32 is supplied to a tracking servo circuit (not shown) as a tracking error signal and is also supplied to a bandpass filter 33.

The output of the band-pass filter 33 is shaped to extract a high-frequency wobble signal included in the tracking error signal, that is, an address identification signal. Next, the address identification signal is supplied to the clock recovery PLL circuit 34, the synchronization extraction timing circuit 35, and the biphase demodulation circuit 36.

The center number and the track number are output from the bi-phase demodulation circuit 36 and supplied to the data register 37 and the CRC check circuit 38. Here, the code data for error detection following the track number is stored in the CRC check circuit 3.
8 to determine whether the track number is correct or not.

The track number signal that is bi-phase modulated is
Consecutive odd track numbers, [2n-1], [2n + 1],
[2n + 3] and consecutive even track numbers, [2n-
2], [2n], [2n + 2]... Are alternately inverted.

Therefore, the track numbers [2n-2] and [2n] of the area ETN of the odd-numbered track (2n-1) in FIG. 3 have opposite phases, and the demodulation of the data can be performed because the reproduction amplitude is canceled out and reduced. The CRC check circuit 38 determines that there is an error. Similarly, the track numbers [2n-1] and [2n + 1] of the area OTN of the even-numbered track (2n) are also determined to be errors.

Thus, for the odd track (2n-1) and the even track (2n), the track numbers [2n-1] and [2n]
Is determined to be correct, and is output from the data register 37 as an address identification signal. That is, even if information is recorded on a land portion of a rewritable or write-once recording medium,
The correct track number can be identified.

Next, a case where a video format signal is recorded on the rewritable optical disc 1 having a pre-groove carrying the above-described track identification signal will be described.

The circuit shown in FIG. 6 is a processing circuit that inserts a digital signal such as the video format signal and PCM audio data to the rewritable optical disk described above into a vertical blanking period of the video format signal, records the signal, and reproduces the signal. . In this processing circuit, an analog video format signal composed of a luminance signal Y, color difference signals (RY), (BY) and a synchronizing signal is input from an input terminal 6, and A / D
The signal is converted into a digital video format signal by the converter 7.

This digital video format signal is written into a FIFO 8 which is a line memory, and is subjected to time axis compression. The writing clock of the luminance signal to the FIFO 8 is 13.5 MHz, and the writing clock of the color difference signal is 2.25 MHz. These clocks are supplied from the PLL clock generation circuit 9 to the read / write control circuit 10. The read clock from the FIFO 8 is 16.2 MHz for both the luminance signal and the color difference signal.

Therefore, the luminance signal is compressed to a ratio of 13.5 (MHz) /16.2 (MHz), that is, 1/2. On the other hand, the color difference signal is 2.2
It is compressed to a ratio of 5 (MHz) /16.2 (MHz), that is, 1 / 7.2. Further, these three compressed video signals are time-division multiplexed into one multiplexed video signal.

Next, the multiplexed video signal output from the FIFO 8 is written to a frame (or field) memory 11 through a digital filter (not shown) in order to remove aliasing noise. In the frame memory 11, time adjustment (synchronization adjustment) between the input multiplexed video signal and the multiplexed video signal to be recorded on the disc is performed. The multiplexed video signal output from the frame memory 11 is read out according to a synchronous clock of 16.2 MHz in the recording mode, supplied to the D / A converter 12, and converted into an analog multiplexed video signal.

Next, the analog multiplexed video signal is modulated in the FM modulation circuit 13, and the FM video signal is output through the selection circuit 14. The FM video signal supplied to the laser diode (none of which is shown) of the disk drive is recorded as an information signal on the track of the land 3 shown in FIG.

As described above, at the time of this recording, the track identification signal taken in from the pre-groove 2 is transmitted to the identification signal decoder circuit.
Supplied to 15. 2 of the track identification signal
If the CP clock pulse train or sector synchronization pulse train
The identification signal is supplied from the decoder circuit 15 to the PLL circuit 16,
The 16.2 MHz synchronous clock in the recording mode is supplied to the timing pulse generation circuit 17. Timing pulse generation circuit 17
The read control of the frame memory 11 is performed in accordance with the timing pulse output from.

A controller 18 including a CPU, a POM, a RAM, and the like receives the track number, the sector number, and the like from the identification decoder 15, and controls the operation of the series of recording modes.

By the way, during the vertical blanking period of the FM video signal, the FM modulation signal of the PCM audio data supplied from the input terminal 19 is inserted into the FM video signal via the selection circuit 14 and recorded.

In FIG. 7A, one frame is divided into 25 sectors of sector 0 to sector 24 as described above. The number of horizontal scanning lines (hereinafter, referred to as lines) of one frame of NTSC and PAL is 525 and 625. Therefore, when one frame is divided into 25, the number of lines in one sector of NTSC and PAL is 21 and 2
It becomes 5, and the rewritable disk can be shared.
Further, 6.5 clock clock per one line NTSC, PAL is a 5.5 clock, even when the carrier component of the wobble signal leaks into the video signal band, 6.5 and 5.5 times the respective leak frequency line frequency f _H Becomes 0.
By shifting by 5f _H , the influence of leakage can be reduced.

In FIG. 7 (a), a field I extends from sector 0 to the middle of sector 12, and a field II extends from the middle of sector 12.
It has become. Therefore, one frame of vertical blanking VB
Is provided between sector 0 and between sector 12 and sector 13. As shown in FIG. 7 (b), the multiplexed video signal is recorded in the first field from the sector 1 to the middle of the sector 12, and the second field in the period from the middle of the sector 13 to the sector 24.

In FIG. 7 (c), during the vertical blanking VB, along with the run-in and run-out that are the synchronization pulses,
PCM audio data is inserted and recorded. Since the PCM audio data is recorded occupying the vertical blanking period in this way, the time code, which is the time information of the multiplexed video signal, is recorded in a synchronous pulse section including at least 1H line other than the vertical blanking period. Input terminal 6 in FIG.
In the synchronization pulse section including at least one line immediately after the vertical blanking period of the video format signal input from the VGA, a signal of a clock pulse train for PLL synchronization is inserted. The time code is superimposed by, for example, bi-phase modulating the clock signal with the time code. That is, the bi-phase modulation circuit
A time code is input to 20, and the clock pulse train of the multiplexed video signal output from the frame memory 11 is bi-phase modulated.

As shown in FIG. 8 (a), the clock pulse train in the case where the time code is not modulated and superimposed is a pulse with a constant inversion interval, thereby performing PLL synchronization.

As shown in FIG. 8 (c), the modulated clock pulse train after being bi-phase modulated according to the time code of FIG. 8 (b) input to the bi-phase modulation circuit 20 has the time code "1" and the time code "1". The inversion interval changes based on “0”.
However, the timing, that is, the phase of the edge of the modulated clock pulse train is the same as that when no modulation is performed.

Therefore, it is possible to superimpose the time code while maintaining the operation of PLL synchronization. When the number of "0" s in the time code increases, the number of edges for PLL synchronization decreases. However, due to the nature of the time code and the large number (bits) of clock pulses, there is no problem in PLL synchronization.

In FIG. 9A, the modulated clock pulse train is 1
During the line period, 80 bits are allocated to two area MCPs for a total of 160
Bits are inserted. The same information can be recorded in these two areas to protect errors, or different information can be entered for different purposes. region
ST is a start signal of a modulated clock pulse train.

A horizontal synchronization signal is inserted in the area SYNC. Also,
Area REF represents the reference level of the video signal, and L
The levels of 1, L2 and L3 are a pedestal, a color reference level, and a white reference (white peak) level. Clock pulse trains for external synchronization are inserted in three areas AUX.

FIGS. 9 (b) and 9 (c) show the last line of the vertical blanking period of fields I and II. The only differences are the time lengths of the horizontal synchronizing signal and the external synchronizing clock pulse train. ). Fields I and II are identified by the different horizontal synchronization signals.

In FIG. 9 (d), the multiplexed video signal of the effective line has a color difference signal of 120 data samples and a luminance signal of 720 data samples.

When reproducing a disc on which PCM audio data and time code are superimposed and recorded, a read signal read by an optical pickup (not shown) is amplified to a required level and supplied to the equalizer 21. After the PCM data in the read signal output from the equalizer 21 is demodulated by the PCM data demodulation circuit 22, the original audio signal is reproduced via a PCM reproduction circuit and an audio amplifier (neither is shown).

On the other hand, FM on which the time code in the read signal is superimposed
The video signal is supplied to the FM demodulation circuit 23, and an analog multiplexed video signal is obtained.

The analog multiplexed video signal is subjected to A / D conversion, dropout compensation, and the like, and is written into the frame (or field) memory 24. The multiplexed video signal, the time axis of which has been adjusted by the frame memory 24, is expanded by the FIFO 25 in the time axis opposite to that at the time of recording, and the original video format signal is finally output from the output terminal 26. Description is omitted.

The modulated clock pulse train in the multiplexed video signal output from the frame memory 24 is demodulated by the bi-phase demodulation circuit 26 to obtain an original time code.

The track number and the like obtained from the track identification signal during the reading operation are supplied from the identification signal decoder 15 to the controller 18 and used for control in the reproduction mode.

In the above embodiment, the modulation of the clock pulse train by the time code is bi-phase modulation. However, the modulation is not limited to this, and another modulation method such as phase modulation may be used.

In the above embodiment, the recording medium is a rewritable optical disk. However, it is needless to say that the recording medium can be applied to a write-once (WO) optical disk.

As described above, in the rewritable recording medium and the recording / reproducing apparatus according to the present invention, the land portion is used as a recording track, and the odd track number is included in the odd track number area of the pregroove and the even track area adjacent thereto. By recording the even track number, during the writing or reading operation on the odd and even tracks, the track numbers of the odd and even track areas can be fetched to identify the correct track number.

[Brief description of the drawings]

FIG. 1 is an enlarged perspective sectional view of a rewritable optical disk which is a rewritable recording medium of the present invention, and FIG. 2 is a pre-groove 2 of FIG.
FIG. 3 is an arrangement diagram in which the format of FIG. 2 is recorded, FIG. 4 is a diagram in which a light beam is applied to a land portion in FIG. 1, and FIGS. 5 and 6 are diagrams of a recording / reproducing apparatus of the present invention. Partial block diagrams, FIGS. 7 (a)-(c) and 9
FIGS. 8A to 8D are signal formats recorded on the rewritable recording medium of the present invention, and FIG. 8 is a timing chart showing a part of the operation of the block diagram of FIG. Description of Signs of Main Part 1 Rewritable Optical Disk 2 Pregroove 3 Land 20 Bi-Phase Modulator 26 Bi-Phase Demodulator

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G11B 7/00 G11B 27/00 G11B 20/12 G11B 7/007

Claims (5)

(57) [Claims] 1. A recordable recording medium having a pregroove bent to carry one address identification number for each unit information section and having a land portion as a recording track, wherein the address identification signal is an odd track number. An odd track number is inserted in the odd track number region in the pregroove sandwiching the land portion serving as the odd track, including an area and the even track number region adjacent thereto, and the pregroove in the pregroove sandwiching the land portion serving as the even track is included. A recordable recording medium wherein an even track number is inserted in an even track area. 2. The recording medium according to claim 1, wherein said address identification signal includes a clock pulse area having a clock pulse train in addition to said odd and even track numbers. 3. The odd-numbered and even-numbered track numbers each include a carrier signal carrying a track number. The carrier waves of successive odd-numbered track numbers are alternately opposite in phase, and the carrier waves of successive even-numbered track numbers are alternately opposite in phase. The recording medium according to claim 1, wherein: 4. The recording / reproducing apparatus for a recording medium according to claim 1, wherein a reading spot is projected on said land portion, and the reflected beam is received by at least two light receiving elements juxtaposed in a track crossing direction. An optical system for obtaining two optical conversion outputs of the light receiving element, and extraction means for setting the track number as a current track number when the track numbers in the two optical conversion outputs coincide with each other. Recording and reproducing device. 5. The apparatus according to claim 1, wherein said extracting means includes demodulating means for bi-phase demodulating the converted output, and error detecting means for detecting whether a track number obtained from the demodulating means is correct or not and outputting a positive track number. The recording / reproducing apparatus according to claim 4, wherein: