JP2000298838A - Information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the information recording medium which can precisely record a prepit signal position even during recording. SOLUTION: The information recording medium records at least some of prepits so that patterns in synchronous information are positioned adjacently and performs recording with multipulses based upon pulse strategy when one mark is formed at the time of information recording; when a pattern in the synchronous information which is much longer than a prepit is positioned adjacently to the prepit and the pattern forms a mark, for example, a pulse or space having a nearly constant amplitude is recorded instead not according to the pulse strategy and a prepit position signal can be detected with high precision even during the recording; and precise recording position control is enabled, and consequently a linking area where unnecessary data are recorded is reduced or made unnecessarily to effectively use a recording area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pre-pit position signal for a recording medium which is recordable, has recorded information tracks wobbled, and has pre-pits formed at predetermined intervals in an area between the information recording tracks. The present invention relates to an information recording method for forming a recording clock based on a wobble signal and a wobble signal to record information with high accuracy.

[0002]

2. Description of the Related Art In recent years, CD-R / RW (Compact Disk)
-Recordable / rewritable optical disc recording / reproducing devices have been put to practical use, and their use in applications such as additional recording and rewriting of data has been progressing. However, when performing recording or rewriting in these recordable optical disk recording / reproducing devices, if the recording control cannot be performed at the location exactly determined at the time of recording, the data is recorded on the previously recorded data, and the old data or the old or new data is recorded. Both data will be destroyed.

Therefore, conventionally, when new data is recorded successively to old data, a predetermined amount of linking area is provided therebetween, for example, dummy data or predetermined data is recorded in the linking area, and thereafter, new data is recorded. The data is recorded. Since information cannot be recorded in this linking area, there is a problem that the recordable capacity is reduced and the recording area cannot be used effectively.

[0004] Therefore, if accurate recording position control can be performed during recording, a linking area for recording unnecessary data can be unnecessary or minimized, and the recording area can be used effectively.

[0005] In this respect, for example, Japanese Patent Application Laid-Open No. 9-326138.
According to the publication, an optical disk having wobbled grooves (information recording tracks) and forming prepits at predetermined intervals in an area (land) between these grooves, and rotation of the optical disk by a wobble signal detected from the groove. There has been proposed a recording apparatus which controls the position of a recording medium and controls the position by a pre-pit signal detected from the pre-pit. According to this proposed example, address information and disk rotation control information can be obtained accurately even at a narrow track pitch. Also, this is not a method of arranging address information formed by pits at the head of a sector in an information recording track (that is, there is no address pit in a groove which is a recording track).
This method enables high-density recording and has excellent compatibility with a read-only disc without causing discontinuity of recorded information due to address information.

In such an optical disk, the track pitch is narrowed for high-density recording. Therefore, leakage from a groove adjacent to a track irradiated with a light beam, that is, crosstalk cannot be ignored. If there is crosstalk from adjacent inner and outer grooves, the wobble signal will be affected by the wobble signal component of the adjacent track, and the amplitude and phase will fluctuate. When recording position control is performed using this wobble signal, especially when phase fluctuation occurs, it is insufficient in terms of accuracy for accurate recording position control. On the other hand, since the pre-pits are arranged so as not to interfere with each other, the pre-pit signal detected from the pre-pit can accurately detect the position on the optical disk, and is suitable for performing accurate recording position control.

However, when a pre-pit signal is detected during recording, the power of the laser light source is not the same as the power for forming a recording mark (ie, it becomes a space).
Since it differs depending on the power, it is difficult to detect the pre-pit signal satisfactorily in both the recording mark portion and the space portion. In particular, the position detection (phase) of the pre-pit signal
May cause an error.

To solve some of these problems, according to Japanese Patent Application Laid-Open No. Hei 10-283638, a recording power for forming a mark and a power for not forming a mark (that is, a space) are used. There has been proposed a pre-pit detection device which has a means for detecting pre-pits and outputs a pre-pit signal by taking the logical sum of the detection results. According to this publication example, the presence or absence of a pre-pit can be reliably detected even during recording.

[0009]

However, it is insufficient to accurately detect the pre-pit position. In other words, when high-density recording is performed, one recording mark is formed not by a single rectangular wave (single pulse) but by a plurality of pulses according to a pulse strategy (laser emission waveform rule). There is a so-called multi-pulse recording method, which is a recording method suitable for large-capacity recording,
Often used. For example, DVD-R is recorded by this method. In particular, when a pre-pit signal is detected during recording by the multi-pulse recording method, since the pulse width of each pulse is short and the light emitting state of the light source is switched in a short time, the pre-pit signal is accurately detected during recording mark formation. It is extremely difficult.

As described above, at least a part of the pre-pit is provided with a mark which is sufficiently longer than the pre-pit in the synchronization information.
When recording adjacently, it is difficult to accurately detect the position (phase) of the pre-pit signal, and there is a problem that a recording clock for information recording cannot be generated accurately. Was. Further, in the worst case, there is a problem that the pre-pit signal itself cannot be detected or erroneously detected, and the precision of the recording clock generation is further deteriorated, which may cause a problem that the precision of the recording position is considerably deteriorated.

Accordingly, the present invention provides a method for recording information on a recording medium which is recordable, has recorded information tracks wobbled, and has prepits formed at predetermined intervals in an area between information recording tracks. In an information recording method for generating a recording clock using a detected pre-pit signal and a wobble signal from a recording information track, the pre-pit signal position can be accurately detected even during recording, thereby providing a highly accurate recording clock. It is an object of the present invention to provide an information recording method which enables generation, reduces or eliminates a linking area for recording unnecessary data, and allows the recording area to be used effectively.

[0012]

According to the present invention, a recording information track is wobbled and a recording medium having prepits formed at predetermined intervals in an area between the information recording tracks is synchronized with a predetermined information unit. When recording the recording information in which the synchronization information is inserted, the synchronization information includes a space or mark pattern that is sufficiently longer than the pre-pit, and at least a part of the pre-pit includes the pattern in the synchronization information. Are recorded adjacent to each other, and when forming one mark at the time of information recording, an information recording method is premised in which recording is performed by multi-pulses according to a pulse strategy.

Under such a premise, the invention according to claim 1, wherein said pattern in the synchronization information sufficiently longer than said pre-pit is located adjacent to said pre-pit and said pattern forms a mark. Is to record with a pulse of substantially constant amplitude without following the pulse strategy, the invention according to claim 2 is to record with a single pulse of constant amplitude without following the pulse strategy, According to the third aspect of the present invention, the recording is forcibly performed so as to form a space regardless of the pulse strategy.

According to the present invention, the synchronization information for synchronizing the recording information for each predetermined information unit is inserted, and the synchronization information includes a pattern of a mark or space which is sufficiently longer than the pre-pits, and at least one of the pre-pits is provided. Note that recording is performed such that the pattern in the synchronization information is positioned adjacent to the section. If the patterns located adjacent to the pre-pits are all spaces, they can always be detected with high accuracy. However, the pattern is a mark for the sake of minimizing the DC component as much as possible when reproducing information. Of course there are things.

Here, in the case of high-density recording, in order to generate one mark, a multi-pulse laser beam is irradiated in accordance with a constant pulse strategy.
Only when recording a long mark in the synchronization information adjacent to the pre-pit, do not follow the pulse strategy, so that the jitter is as close to the minimum as possible if worse than if this pulse strategy is followed. By recording with a pulse of a certain constant amplitude, forcibly recording with a single pulse laser beam of a weak constant amplitude, or by forcibly forming a space with the power of the laser beam as an erasing power level. Thus, pre-pits can be detected with high accuracy even during recording. By generating such a pre-pit signal, the above problem is solved.

According to a fourth aspect of the present invention, in the information recording method of the first, second or third aspect, the pre-pits located in the synchronization information on the information recording track include a plurality of the synchronization information. When one pre-pit appears in the block, when the pre-pit appears in the block, when the pre-pit appears in the block, the synchronization information in the block At the timing when appears, the recording process that does not follow the pulse strategy is not performed.

According to the fourth aspect of the present invention, when recording the synchronization information, the recording does not follow the pulse strategy and the recording is not performed by forcibly setting the space or stopping the multi-pulse. The DC fluctuation and the increase in the synchronization detection error rate can be reduced.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. First, a basic principle of an information recording method according to the present embodiment will be described with reference to an embodiment of a recording medium suitable for the present invention and a form of information to be recorded on the recording medium.

In the recording medium, for example, as shown in FIG. 1, prepits 3 are formed at predetermined intervals on grooves 1 which are information recording tracks and lands 2 in an area between the grooves 1. The groove 1 is meandering (wobble). For a more specific description, the following description will be given taking a DVD-R as a recording medium having this mode as an example. DV
In DR, the groove 1 as the information recording track wobbles at a predetermined frequency.

FIG. 2 schematically shows the arrangement of wobbled grooves 1 and prepits 3 of a DVD-R.
The data recorded on the recording medium is divided in advance into sync frames, which are information units, and one sector is composed of 26 sync frames, and one ECC (Error Correcting Code) is composed of 16 sectors.
e) A block is configured. At the head of each sync frame, there is synchronization information SY for synchronizing each sync frame. The recorded original data is converted into a modulation code according to a predetermined modulation rule. In order to modulate 8 bits of original data into a 16-bit code, "8/1
6 modulation. A detailed description of the modulation rule is omitted here.
On the recording medium, the modulation code sequence is stored in an NRZI (Non Return
to Zero Inverted) Record the converted pulse train. Assuming that one channel bit length of a pulse train to be recorded is T, the shortest pulse width is 3T and the longest pulse width is 11T. In addition, when modulation is performed, a device for suppressing a low frequency component of the recording pulse train is used (detailed description is omitted). To determine the low frequency component suppression, a so-called DSV (Digita
l Sum Value). DSV means that one state of a bit string having two states is +1 and the other state is-
1 is a value accumulated from the beginning of the bit string. If the absolute value of the DSV is small, the low frequency component is small, and the modulation code is selected so that the DSV of the recording pulse train is small.

Between the recording pulse trains, synchronization information SY is inserted for each sync frame (here, 3
2 bits). In order to reliably capture the synchronization information SY, that is, to ensure synchronization of the sync frame, the synchronization information SY includes a pulse having a 14T width which is sufficiently longer than 11T which is the longest pulse width appearing in the data modulation portion (hereinafter referred to as appropriate). , "Sync pulse" (referred to as "pattern" in the claims). In addition, a plurality of types of synchronization information SY are provided so that a frame position in a sector can be identified. Each synchronization information SY satisfies a modulation rule at a connection portion with a previous sync frame and suppresses low frequency components. , And a plurality of patterns.

The enlarged view also shown in FIG. 2 shows the synchronization information SY
In order to suppress the low frequency component as much as possible (determined by the above-mentioned absolute value of DSV), either pattern 1 or pattern 2 is selected by paying attention to 14T. That is, the sync pulse of the 14T width pulse is
A mark to be recorded (pattern 2) or a space (pattern 1) is selected (in the figure, a mark is recorded for a positive pulse, and a space for a negative pulse). Normal,
Since the synchronization information SY is short enough for the entire recording information,
Even if the sync pulse mark in the synchronization information is forcibly changed to a space, generation of some low frequency components is within a sufficiently allowable range. However, since the synchronization information becomes an error, it cannot be used as the synchronization information at the time of reproducing the information. In this case, since the synchronization timing generated predictively by the circuit based on the correct synchronization information detected before this is used as the synchronization position, there is no major problem. Also, as a merit of forcing, when a phase change medium is used, a long recorded mark of 14T located at the leading end of the information unit to be recorded is deteriorated when repeatedly recorded (overwritten). This may be alleviated earlier.

On the other hand, the recording medium has a groove 1 wobbled in advance at a predetermined constant frequency (wobble frequency fw),
One pre-pit is formed for each sync frame on one of the lands 2 adjacent to the groove 1 (in this embodiment, on the outer circumference side) to indicate a synchronization signal (hereinafter, this pre-pit is referred to as a “sync”). Pre-pit “3”
s) and 0 as address information or the like.
To 2 pre-pits 3 are formed. As shown in FIG. 3, the sync frames including the pre-pits 3 include even-numbered sync frames (hereinafter, referred to as “EVEN frames”) and odd-numbered sync frames (hereinafter, “ODD frames”).
Normally form a pair, and the pre-pits 3 are usually arranged at the position of the EVEN frame. However, if it is expected that the pre-pits 3 will be arranged on both adjacent lands 2, the mutual pre-pits 3 In order to avoid such a situation, they are arranged shifted to the ODD frame. That is, E which constitutes a pair
The pre-pit 3 is arranged only in one of the frames VEN and ODD. The other adjacent (inner circumferential side) land 2 has a pre-pit 3 'associated with another groove.
Are formed. The wobble frequency fw is eight times the sync frame frequency, and the pre-pits 3 are arranged so as to be located at approximately the first three vertices of wobbles in one sync frame. The first prepit among them is the sync prepit 3s. The length of the pre-pit 3 in the track direction is preferably as small as possible within a detectable range in order to reduce the influence of increase in the reproduction jitter due to bleeding of the recording mark in the pre-pit direction. Often done.

When data is recorded in the groove 1 of the recording medium, the sync pulse (record mark or space having a length of 14T) in the synchronization information SY is synchronized with the pre-pit so that it is positioned adjacent to the sync pre-pit 3s. Recorded. At this time, the pre-pit signal is a reference for generating a high-precision recording clock for controlling the recording position so that the recording can be performed with high accuracy and synchronization. Therefore, the detection accuracy of the pre-pit signal is important. This is important not only during recording, but also during reproduction or rewriting of the already-recorded track.

FIG. 3A is a schematic diagram showing the relationship between the recording medium on which information is recorded in synchronization with the pre-pits 3 and the pre-pit signal. Sync pulses (record marks in the figure) 4 are recorded adjacent to each other in the sync pre-pits 3s. However, since the recording data portion is adjacent to the pre-pits 3 other than the sync pre-pits 3s, the recording marks of 3T to 11T are recorded. Alternatively, recording is performed with spaces adjacent to each other and with a phase shift. The dotted line in the pre-pit signal in FIG. 3A is a pre-pit signal at the time of non-recording, and this is also the case when a sufficiently long (for example, sync pulse) space is recorded with respect to the pre-pit 3. As can be seen, the pre-pit signal Spit binarized by a constant slice level Vth
When a recording mark is formed on an adjacent track, phase fluctuation occurs. Therefore, if the sync pre-pit 3s is detected at the peak of the detection signal, the phase shift is considerably reduced. However, in the pre-pits 3 other than the sync pre-pits 3s, the phase varies depending on the recording information. In other words, the sync pre-pit 3s has no phase shift.

On the other hand, FIG. 3B is a schematic diagram showing the relationship between the pre-pit signal during recording of information in synchronization with the pre-pit 3 and the recording power of the light source. Here, for simplicity, it is assumed that a space is formed when the light source is at power P1, and a mark is formed when the light source is at power P2. The power applied to the sync pre-pits 3s is constant (P1 or P2) while the applied light beam is applied to the pre-pits 3 other than the sync pre-pits 3s. The converted pre-pit signal Spit fluctuates in phase depending on the recording information. In addition, when recording by a multi-pulse recording method according to a certain pulse strategy as shown in FIG.
It is extremely difficult to accurately detect the prepit signal Spit during the formation of a recording mark, not only for the prepits 3s other than the sync prepits 3s but also for the sync prepits 3s.

In order to make the recording position accurate, it is preferable to generate the recording clock by using the sync pre-pits 3s. Further, it is more desirable that the sync pulse adjacent to the sync pre-pit 3s is a space. The information recording apparatus of the present embodiment forcibly forms a space without following a pulse strategy even when a mark should be originally recorded as a sync pulse in synchronization information adjacent to the sync pre-pit 3s. Thus, accurate recording position control is performed. Or sync pre-pit 3
When a mark must be recorded as a sync pulse adjacent to s, multi-pulse recording according to the pulse strategy shown in FIG. 4 is stopped, and a constant amplitude is set so as to minimize the jitter as much as possible. Or a single pulse of a constant amplitude with a weak power (bias power) forcibly detects the sync pre-pit 3s with high accuracy. By implementing such a method of the present embodiment, a high-precision recording clock can be generated because the phase of the sync pre-pit detection signal does not shift. That is, if a peak detection circuit including a differentiating circuit is used to detect the peak position of the sync pre-pit 3s, it is possible to accurately detect whether the sync pulse is a mark or a space. Since the same method is used for detecting the sync pre-pit 3s after recording by such a method, the peak phase of the sync pre-pit 3s can be accurately detected.

Next, the overall configuration and operation of an information recording / reproducing apparatus for realizing the above-described information recording method will be described with reference to FIGS.

FIG. 5 shows the overall configuration of the information recording / reproducing apparatus. In FIG. 5, an information recording / reproducing apparatus includes an optical pickup (PU) 10, a laser driving unit 11, an encoder 12, a controller 13 including an interface unit with an external host computer or the like (not shown), a recording medium. 9, a spindle motor 14, a servo means 15, a reproduction signal processing means 16, a decoder 17,
Pre-pit signal detection means 18, pre-pit signal decoder 19, rotation control means 20, wobble signal detection means 21, recording clock signal generation means 22, pre-pit position signal detection means 23, and recording position control signal generation means 2
4 and synchronization information instructing means 25. In this figure, control signals from the controller 13 to the servo means 15, the rotation control means 20, the laser driving means 11, the reproduction signal processing means 16 and the like are omitted.

The optical pickup 10 includes a laser diode as a light source, a light receiving means, etc., focuses a light beam emitted from the laser diode on a recording medium 9, and converts reflected light from the recording medium 9 into a light receiving signal. I do. The laser driving unit 11 controls and drives the light amount of the laser diode to a desired value, and modulates the laser diode based on the recording data Wdata during recording. At this time, modulation is performed using the recording clock signal Swck as a reference signal. Encoder 1
Reference numeral 2 uses the recording clock signal Swck as a reference signal, performs interleaving processing, ECC processing, 8/16 modulation processing, addition of a synchronization signal, and the like on data to be recorded input from the controller 13, to generate recording data Wdata. At this time, recording is started according to the recording position control signal. That is,
The output of the recording data Wdata is started. A more detailed configuration and operation of the encoder 12 will be described later.

The reproduction signal processing means 16 processes a light receiving signal from the optical pickup 10 and generates a reproduction signal, a servo signal and a push-pull signal Spp. here,
As is well known, the push-pull signal is a difference signal of the output of the light receiving element divided into two by receiving the reflected light from the recording medium 9 in parallel across the track tangential direction with the light receiving element divided in two. FIG. 6 shows an example of the push-pull signal Spp. As shown in FIG. 6, the push-pull signal Spp is a signal in which a wobble signal and a pre-pit signal are superimposed. As for the pre-pit component, pre-pits 3 formed on lands 2 on the inner and outer circumferences adjacent to the groove 1 being scanned appear vertically, and FIG.
In the figure, the upper pre-pit 3 is the pre-pit associated with the groove (appears when the wobble is substantially maximum). Among them, the leading pre-pit is the sync pre-pit 3s, and usually appears every two sync frames. However, when switching between EVEN and ODD frame shift, 1
Or it may be three sync frame intervals. On the other hand, the lower pre-pit 3 ′ is a pre-pit associated with another groove 1. Therefore, the phase of the pre-pit 3 'with respect to the wobble changes every moment. The push-pull signal Spp may be a signal obtained by subjecting a difference signal of the output of the light-receiving element divided into two to gain adjustment (for example, adjustment using a light-receiving sum signal) or the like so that signal processing in the subsequent stage is easy. . Further, the push-pull signal Spp is HPF (High P
The signal after the DC component is suppressed by the ass filter may be used. Then, the offset of the push-pull signal Spp can be removed. The decoder 17 decodes the reproduced signal to generate a demodulated signal and outputs the signal to the controller 13.

The servo means 15 controls the light beam from the optical pickup 10 to irradiate an arbitrary position on the recording medium 9 based on the servo signal. The rotation control means 20 controls the rotation of the recording medium 9 so that the wobble signal Swbl has a predetermined frequency, and the spindle motor 14 rotates the recording medium 9 based on the control signal. Here, the wobble signal is used, but since the pre-pits 3 are also formed at predetermined intervals, this may be used.

The pre-pit signal detecting means 18 generates a pre-pit signal Spit from the push-pull signal Spp. Push-pull signal Spp and predetermined threshold Vthpit (see FIG. 6)
And a comparator for comparing. The pre-pit signal decoder 19 obtains address information or the like pre-formatted on the recording medium 9 by decoding the pre-pit signal Spit, and outputs it to the controller 13.

The wobble signal detecting means 21 extracts a wobble signal from the push-pull signal Spp by BPF (Band Pass Filter) or the like, and detects the wobble signal Swbl. The recording clock signal generating means 22 outputs the wobble signal S
wbl and a high-precision sync pre-pit position signal Spit detected by the pre-pit position signal detecting means 23,
The recording clock signal Swck is generated only by the sync pre-pit position signal Sspit. Data to be recorded is subjected to signal processing based on the recording clock signal Swck. However, in the case of the method in which the sync pulse is forcibly set as a space, the amplitude of the sync pre-pit signal included in the pre-pit signal Spit does not fluctuate greatly even during recording, so that the phase is accurate even in the detection method using the threshold. Therefore, this may be selected and used as a pre-pit position detection signal. Normally, the recording clock generating means 22 uses a so-called PLL (Ph
ase Locked Loop) circuit.

The pre-pit position signal detecting means 23 detects a sync pre-pit position signal Sspit in which the position of the pre-pit 3 is detected with high precision from the push-pull signal Spp. The signal is detected by detecting the peak of the sync pre-pit signal. Can be accurately detected. The peak detecting circuit for this purpose is generally constituted by a differentiating circuit or the like.
Then, from consecutive pre-pits 3 to sync pre-pits 3
In order to identify s, before the sync pre-pit signal, FIG.
As can be seen from the figure, since the pre-pit signal does not come beyond the 3 wobble signal interval, it can be determined by utilizing this fact. For example, when the pre-pit 3 always comes, three wobble times are measured by means such as a timer, and when the pre-pit 3 is detected within this time, the pre-pit 3 is detected when the timer is off, not the sync pre-pit 3s. The pre-pit 3 is the sync pre-pit 3s.

The pre-pit signal detecting means 18 is composed of a simple comparator with a constant slice level so that information such as an address on the recording medium 9 can be detected by the next pre-pit signal decoder 19.

However, in the system in which the sync pulse is forcibly used as a space, the detection of the sync pre-pit signal and the detection of the address information can be shared.

The recording position control signal generating means 24 includes a PLL
A frame synchronizing signal Sfs phase-synchronized with the sync pre-pit position signal is generated by a circuit and a timer circuit (used as a window circuit that rejects a signal that should not arrive). Therefore, even if the sync pre-pit position signal is erroneously detected due to, for example, noise, sometimes,
The frame synchronization signal Sfs can be accurately detected. Then, the recording position control signal generating means 24 responds to the recording start instruction from the controller 13 and outputs the sync pre-pit position signal Ssp
A recording position control signal indicating a recording start position synchronized with it is generated and output to the encoder 12.

The synchronization information instructing means 25 takes AND (logical product) of the frame synchronization signal Sfs and the sync pre-pit position signal Sspit, and notifies the encoder 12 that the sync pre-pit has been detected without fail. That is, when writing the sync pulse (pulse of 14T width) included in the synchronization information SY, instead of forcibly setting the space or stopping the multi-pulse as in the present embodiment, EVEN of one sync frame is always used. When the sync pre-pit is detected in the frame, since the sync pre-pit does not come in the next ODD frame, the space pulse is forcibly set to the space in the sync pulse (14T width pulse) of the ODD frame at this time, and the multi-pulse is stopped. In other words, recording is performed by a normal multi-pulse according to the pulse strategy. In this way, DSV disturbance or jitter at the time of reproduction can be minimized.

Next, the detailed structure and operation of the encoder 12 will be described with reference to FIG. FIG. 7 shows an encoder 1
2 shows a configuration example of a related part. The encoder 12 includes a data preprocessing unit 30, an 8/16 modulation unit 31, a synchronization information generation unit 32, and an NRZI conversion unit 33. As described above, these processes are performed by the recording clock signal S.
The start of the output of the recording data Wdata from the NRZI conversion means 33 is controlled by the recording position control signal on the basis of wck.

The data pre-processing means 30 includes the controller 13
It performs ECC processing, interleaving processing, and the like on the input recording information.

The 8/16 modulation means 31 defined here is:
The recording information after the data pre-processing and the synchronization information SY are added for each sync frame, and the recording information after the data pre-processing is appropriate so that the DSV approaches zero (low frequency components are suppressed). An 8/16 modulation rule is selected, and a pattern of the synchronization information SY is selected. That is, the synchronization information SY is
It is selected from a plurality of codes in order to suppress low frequency components in consideration of the connection with the previous sync frame. When selecting one of the codes according to the low frequency component suppression condition, it is determined whether the sync pulse becomes a recording mark or a space. The 8/16 modulating means 31 sends the signal to the laser driving means 11 since the position of the sync pulse (14T pulse) is known. In other words, in order to detect the sync pre-pit with high accuracy at the time of writing, the laser driving means 11 knows where this signal has come from, and forcibly sets a space or a constant amplitude at this timing. It can be determined by the output state of the NRZI conversion means 33 and a control signal Cod described below. The synchronization information generating means 32 determines whether the sync pre-pit position signal detected by the synchronization information instructing means 25 has detected the sync pre-pit when outputting the EVEN frame of one sync frame or the ODD frame. When the sync pre-pit is detected in the EVEN frame, the sync pre-pit does not come in the next ODD frame. Therefore, in the ODD frame sync pulse (14T width pulse) in this case, the space is forcibly set. Alternatively, a control signal Cod for recording with a normal multi-pulse is sent to the laser driving means 11 without stopping the multi-pulse (making the pulse of a constant amplitude). Although not shown, the control signal Codd is also sent to the pre-pit position signal detecting means 23. If the control signal is used as a control signal for gating so as not to detect the sync pre-pit in the case of the ODD frame when the above condition is satisfied, the reliability is improved. High sync pre-pit detection.

The NRZI conversion means 33 performs NRZI conversion on the modulation code output from the 8/16 modulation means 31, and converts it into a recording pulse train (recording data Wdata).

FIG. 8 shows the laser driving means 11. The laser driving unit 11 is configured to include a pulse strategy generation circuit 34. When the output of the NRZI conversion unit 33 indicates a level (for example, a high level) for recording a mark, the laser driving unit 11 applies one recording mark. A multi-pulse current according to a pulse strategy optimal for the recording medium 9 as shown in FIG. 4 is supplied to the laser diode. However, if the sync pulse (14T pulse) is generated without the control signal Comd and the output of the NRZI conversion means 33 is at a level for recording a mark, the space is forcibly set or multi-pulse recording is performed. Stops and generates a constant amplitude pulse current.

Next, the above contents will be described with reference to a time chart shown in FIG. When a mark has to be recorded as a sync pulse (14T) included in the record information, in order to detect the sync pre-pits 3s with high accuracy, a space is forcibly set, or multi-pulse recording is stopped and a single pulse of a constant amplitude is stopped. To record. Therefore, in the example of the DVD-R shown in FIG. 3 and the like, when writing the mark of the sync pre-pit 3s in the EVEN frame, the space is forcibly set, or the multi-pulse recording is stopped and the recording is performed with a single pulse of a constant amplitude. . Pre-pit 3 on EVEN frame
Since there is no pre-pit in the ODD frame, there is no need to set the mode to detect the sync pre-pit 3s with high accuracy. To determine this, the control signal Cod is used as a gate signal that does not detect sync pre-pits.
d is used. When there is a pre-pit 3 on the ODD side as indicated by the symbol A in the time chart of the figure, there is no pre-pit on the immediately preceding EVEN side, but the circuit operation is compulsory as mark writing of the sync pre-pit 3s. A mode in which recording is performed in a space or in which multi-pulse recording is stopped and a constant amplitude is performed works. However, on the ODD frame side, this mode works only when there is the pre-pit 3, so that jitter increase or DC fluctuation is reduced. In addition,
In FIG. 9, sync pre-pit 3 in the pre-pit signal
The combination of two or one pre-pit 3 following s indicates the information of whether the information pit is "1" or "0" and the head of the information block, and collects a certain number of frames. Enter address information etc.

As a method of detecting the sync pre-pits 3s with high accuracy in the present embodiment as described above, there is a method of reducing the number of the sync pre-pits 3s. For example, it is halved. These may be traded off in accordance with the specifications required for the system.

[0047]

According to the first aspect of the present invention, when the pattern in the synchronization information recorded so as to be located adjacent to the prepit serving as the basis of the recording position control is a mark, the pattern follows the pulse strategy. Synchronization information is generated using pulses of almost constant amplitude instead of multi-pulses, so pre-pit position signals can be detected with high accuracy even during recording, and accurate recording position control becomes possible, thereby making it unnecessary. Thus, the number of linking areas for recording unnecessary data can be reduced or made unnecessary, and the recording area can be used effectively.

According to the second aspect of the present invention, it is the same as the first aspect of the present invention, but when a pattern in the synchronization information is recorded as a mark, a jitter minimum does not substantially follow a pulse strategy. Since recording is performed with a pulse having a constant amplitude, DC fluctuation during reproduction can be reduced, and an increase in an error rate for reading synchronization information can be reduced.

According to the third aspect of the present invention, it is the same as the first aspect of the present invention, but when a pattern in the synchronization information is recorded as a mark, a space is forcibly formed without following the pulse strategy. Pre-pits can be detected with high accuracy during writing and during reproduction.If a long mark is repeatedly recorded at the same position repeatedly on a phase-change type recording medium, the recording medium is liable to be deteriorated. It can also be reduced.

According to the fourth aspect of the present invention, when a mark is recorded as a pattern of synchronization information, a space is forcibly formed, or recording is performed with multipulses stopped. And an increase in the synchronization detection error rate can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a track configuration example of a recording medium according to an embodiment of the present invention.

FIG. 2 is an explanatory view schematically showing the arrangement of grooves and prepits.

3A is a schematic diagram showing a relationship between a recording medium on which information is recorded in synchronization with prepits and a prepit signal, and FIG. 3B is a diagram showing a prepit signal during recording of information in synchronization with prepits; FIG. 4 is a schematic diagram showing a relationship between the recording power of the light source and the recording power of the light source.

FIG. 4 is a principle waveform diagram showing a multi-pulse recording method.

FIG. 5 is a block diagram illustrating an overall configuration of an information recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 6 is a waveform chart showing an example of a push-pull signal.

FIG. 7 is a block diagram illustrating a configuration example of an encoder.

FIG. 8 is a block diagram illustrating a configuration example of a laser driving unit.

FIG. 9 is a time chart illustrating an operation control example.

[Explanation of symbols]

 1 information recording track 3 pre-pit 9 recording medium

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shigehiro Masui 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (Reference) 5D090 CC01 DD03 DD05 FF17 GG03 GG27

Claims (4)

[Claims] 1. Synchronization information for synchronizing every predetermined information unit is inserted into a recording medium in which recording information tracks are wobbled and prepits are formed at predetermined intervals in an area between the information recording tracks. When the recording information is recorded, the synchronization information includes a space or mark pattern that is sufficiently longer than the pre-pit, and the pattern in the synchronization information is positioned adjacent to at least a part of the pre-pit. When recording and forming one mark during information recording, in an information recording method for recording by a multi-pulse according to a pulse strategy, the pattern in synchronization information sufficiently longer than the pre-pit is positioned adjacent to the pre-pit. When the pattern forms a mark, the pulse strategy Information recording method is characterized in that so as to record a substantially constant amplitude pulses without following chromatography. 2. Synchronization information for synchronizing every predetermined information unit is inserted into a recording medium in which recording information tracks are wobbled and prepits are formed at predetermined intervals in an area between the information recording tracks. When the recording information is recorded, the synchronization information includes a space or mark pattern that is sufficiently longer than the pre-pit, and the pattern in the synchronization information is positioned adjacent to at least a part of the pre-pit. When recording and forming one mark during information recording, in an information recording method for recording by a multi-pulse according to a pulse strategy, the pattern in synchronization information sufficiently longer than the pre-pit is positioned adjacent to the pre-pit. When the pattern forms a mark, the pulse strategy Information recording method is characterized in that so as to record a single pulse of constant amplitude without following chromatography. 3. Synchronization information for synchronizing every predetermined information unit is inserted into a recording medium in which recording information tracks are wobbled and prepits are formed at predetermined intervals in an area between the information recording tracks. When the recording information is recorded, the synchronization information includes a space or mark pattern that is sufficiently longer than the pre-pit, and the pattern in the synchronization information is positioned adjacent to at least a part of the pre-pit. When recording and forming one mark during information recording, in an information recording method for recording by a multi-pulse according to a pulse strategy, the pattern in synchronization information sufficiently longer than the pre-pit is positioned adjacent to the pre-pit. When the pattern forms a mark, the pulse strategy Information recording method is characterized in that so as to record as forced a space without following chromatography. 4. When the pre-pits located in the synchronization information on the information recording track constitute one block including a plurality of the synchronization information, only one pre-pit is arranged in the block. When the pre-pit appears in the block with respect to the recording medium to be recorded, at the timing when the synchronization information appears in the block,
4. The information recording method according to claim 1, wherein a recording process that does not comply with the pulse strategy is not performed.