JP4132525B2 - Information recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention records information on a recordable recording medium having prepits formed at predetermined intervals in an area between information recording tracks by performing recording position control with high accuracy based on a prepit position signal. The present invention relates to an information recording apparatus such as a DVD-R drive apparatus.
[0002]
[Prior art]
2. Description of the Related Art In recent years, recordable optical disc recording / reproducing apparatuses that add data to or rewrite data on an optical disc such as a CD-R / RW that is a recordable recording medium have been put into practical use.
[0003]
When performing additional recording or rewriting in such a recordable optical disc recording / reproducing apparatus, if accurate recording position control cannot be performed at the time of recording, data will be recorded over the previously recorded data. Will be destroyed.
[0004]
Therefore, when recording new data continuously with the old data, a predetermined amount of linking area is provided between them, for example, dummy data or predetermined data is recorded in the linking area, and then the new data is recorded. It was.
[0005]
However, since information cannot be recorded in the linking area, the recordable capacity is reduced, and there is a problem that the recording area of the recording medium cannot be used effectively.
[0006]
Therefore, if accurate recording position control is realized at the time of recording, the linking area for recording unnecessary data can be kept unnecessary or minimized, so that the recording area of the recording medium can be used effectively.
[0007]
Conventionally, an optical disc having wobbled grooves and prepits formed at predetermined intervals in an area between the grooves (referred to as “land”), and the rotation of the optical disc is controlled by a wobble signal detected from the wobble and There has been proposed an information recording apparatus (for example, see Japanese Patent Application Laid-Open No. 9-326138) for controlling the position based on the detected pre-pit signal.
[0008]
According to such an information recording apparatus, address information and optical disc rotation control information can be obtained accurately even at a narrow track pitch.
In addition, since address information is not arranged at the head of the sector, that is, there is no address pit in the recording track groove, high-density recording is possible, and the recorded information is not discontinuous due to the address information. It can also be compatible with a dedicated disk.
[0009]
However, in the optical disk as described above, the track pitch is narrowed in order to perform high-density recording, so that leakage from the groove adjacent to the track irradiated with the light beam, so-called crosstalk, cannot be ignored.
[0010]
When there is such crosstalk from the inner and outer peripheral grooves, the wobble signal receives interference from the wobble signal component of the adjacent track, and the amplitude and phase fluctuate.
When recording position control is performed using the wobble signal as described above, particularly when phase fluctuation occurs, the recording position control is not sufficient for accurate recording position control.
[0011]
On the other hand, since the prepits are arranged so as not to interfere with each other, the prepit signal detected from the prepit can accurately detect the position on the optical disc, and is suitable for accurate recording position control.
[0012]
However, when detecting the prepit signal during recording, the power of the light source is different between the power for forming the recording mark and the power for not forming the recording mark (that is, the power for forming the space). In particular, there is a problem that an error occurs in the position detection of the prepit signal.
[0013]
In order to solve some of the above problems, there is a means to detect each prepit by recording power and reproduction power (power that does not form a recording mark), and a prepit signal is output by taking the logical sum of each detection result. A prepit detection device (see, for example, Japanese Patent Application Laid-Open No. 10-283638) applied to an information recording device is proposed. According to such a prepit detection apparatus, the presence or absence of prepits can be reliably detected even during recording.
[0014]
However, even the use of the prepit detection device as described above is insufficient to accurately detect the prepit position.
[0015]
Furthermore, there is a so-called multi-pulse recording method in which one recording mark is formed not by a single rectangular wave but by a plurality of pulses, which is a recording method suitable for large-capacity recording. It has been.
[0016]
For example, it is recorded by this method on a recording medium such as a DVD-R.
In particular, when detecting a pre-pit signal during recording by this multi-pulse recording method, since the individual pulse widths are short and the light emission state of the light source is switched in a short time, the pre-pit signal is accurately detected during recording mark formation. It was extremely difficult.
[0017]
Also, when detecting the prepit signal in the recorded area, the amplitude of the prepit signal fluctuates due to the difference in reflectance between the recording mark and the space, and the position of the prepit signal depends on the positional relationship between the prepit and the recording mark. An error may occur in detection.
[0018]
As described above, the conventional technique has a problem that it is difficult to accurately detect the recorded area, in particular, the position of the pre-pit signal during recording, and as a result, the recording position cannot be accurately controlled. .
[0019]
Furthermore, in the worst case, there is a problem that the pre-pit signal itself cannot be detected or erroneously detected, which causes a problem that the recording position control cannot be performed accurately or is erroneously controlled. It was.
[0020]
Therefore, the present applicant has filed an invention (Japanese Patent Application No. 11-155711) for solving such a problem.
The present invention provides an information recording apparatus for controlling a recording position by a prepit signal detected from a prepit when recording information on a recording medium in which prepits are formed at predetermined intervals in an area between information recording tracks. Alternatively, an information recording method and apparatus for accurately detecting a pre-pit signal position even during recording is provided, and synchronization information for synchronizing every predetermined information unit is inserted into the recorded information. Focusing on the fact that recording is performed so that the synchronization pattern is positioned adjacent to at least a part of the prepit, and the synchronization pattern positioned adjacent to the prepit is If it is a space, it becomes possible to detect prepits with high accuracy even during recording and in the recorded area. By generating a synchronization information is obtained by solving the above problems.
[0021]
[Problems to be solved by the invention]
However, the above-described invention of the present applicant also has a problem that the low frequency component of the recording pulse train increases.
[0022]
The present invention has been made in order to solve the above-described problems. When information is recorded on a recording medium in which prepits are formed at predetermined intervals in an area between information recording tracks, a prepit signal detected from the prepits is used. In an information recording apparatus for controlling the recording position, it is possible to control the recording position with high accuracy, to make the recording area effective by using less and unnecessary linking areas for recording unnecessary data, and further Is intended to prevent an increase in the low frequency component of the recording pulse train.
[0023]
  In addition,The recording medium may be prerecorded in advance to record disc information or the like on part or all of the recording track.
  If the recording information to be pre-recorded is not made in view of the above problems, the above problems will occur when the information is additionally recorded or overwritten on this recording medium.
[0025]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a recording medium in which synchronization information for synchronizing every predetermined information unit is inserted into a recording medium having prepits formed at predetermined intervals in an area between information recording tracks. In the information recording apparatus for performing recording so that the synchronization information includes a synchronization pattern that is sufficiently longer than the pre-pit when the information is recorded, and the synchronization pattern is positioned adjacent to at least a part of the pre-pit. First synchronization information generating means for generating first synchronization information such that the space becomes a space, second synchronization information generating means for generating second synchronization information for suppressing low frequency components of the recording pulse train, and Synchronization information selection means for selecting and outputting either the first synchronization information or the second synchronization information, and a prepit position signal indicating the position of the prepit are detected. Prepit position signal detecting means, recording position control signal generating means for generating a recording position control signal based on the prepit position signal, and first synchronization information or second synchronization information selected by the synchronization information selecting means Encoding means for converting a modulation code obtained by modulating recording information in accordance with a predetermined modulation rule into a recording pulse train and starting output of the recording pulse train in accordance with the recording position control signal.
[0026]
Further, the recording position control signal generating means is provided with means for generating a recording position control signal based on a part of the pre-pit position signal, and the synchronization information selecting means is a part that serves as a reference for generating the recording position control signal. It is preferable to provide means for selecting the first synchronization information when the synchronization pattern is located adjacent to the prepit, and selecting the second synchronization information otherwise.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
  Embodiments of the present invention will be specifically described below with reference to the drawings.
  First, an embodiment of the present inventionUsed for information recording equipmentA recording medium and the form of information recorded on the recording medium will be described.
  thisIn the recording medium, prepits are formed at predetermined intervals on lands which are areas between grooves which are information recording tracks.
[0030]
In order to explain more specifically, the following description will be given by taking DVD-R as a recording medium having this form as an example.
Further, in the DVD-R, a groove which is an information recording track is wobbled at a predetermined frequency.
[0031]
FIG. 3 is a diagram schematically showing the arrangement of wobbles and prepits on the DVD-R.
As shown in FIG. 3A, the data recorded on the DVD-R is divided in advance for each sync frame 2, which is an information unit. One sector is composed of 26 sync frames, and one ECC (Error Correcting) is composed of 16 sectors. Code) blocks.
[0032]
In the head area 3 of each sync frame 2, 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. Although the original data 8 bits are modulated into a 16-bit code, it is called 8/16 modulation. However, since the modulation rule is a known technique, a detailed description thereof is omitted.
[0033]
On the DVD-R, a pulse train obtained by converting the modulation code train into NRZI (abbreviation of “Non Return to Zero Inverted”) is recorded.
If one channel bit length of the pulse train to be recorded is “T”, the shortest pulse width is “3T” and the longest pulse width is “11T”.
Further, a device for suppressing the low-frequency component of the recording pulse train has been devised during modulation (the device is also a known technology and will not be described in detail).
[0034]
The absolute value of so-called DSV (abbreviation of “Digital Sum Value”) is used to determine the suppression of the low frequency component.
The DSV is a value accumulated from the top of the bit string, with one state of the bit string taking two states being “+1” and the other state being “−1”.
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.
[0035]
Synchronization information: SY is inserted for each sync frame between the recording pulse trains, for example, 32 bits.
The synchronization information: SY is sufficiently longer than “11T”, which is the longest pulse width appearing in the data modulation portion, so that the synchronization information: SY can be reliably captured, that is, the sync frame synchronization can be surely obtained. A synchronization pattern (hereinafter also referred to as “sync pulse” as appropriate) which is a pulse having a width is embedded.
[0036]
Also, it has multiple types of synchronization information: SY so that the frame position in the sector can be identified, and each synchronization information: SY satisfies the modulation rule at the connection part with the previous sync frame and suppresses low frequency components In order to achieve this, a plurality of patterns are selected.
[0037]
FIG. 3B is an enlarged view of the portion of the synchronization information: SY. In order to suppress the low frequency component as much as possible (determined by the absolute value of the DSV described above), the pattern 1 or the pattern 2 Select one.
[0038]
That is, the sync pulse of the “14T” width pulse is selected as a recording mark (pattern 2) or a space (pattern 1).
In the figure, a positive pulse is a recording mark and a negative pulse is a space.
This can be easily distinguished from the code to be generated and the polarity of the last pulse of the previous sync frame.
[0039]
For example, in FIG. 3B, since the last pulse of the previous sync frame is a mark, if pattern 1 is selected, the sync pulse is a space, whereas if the last pulse is a space, pattern 2 is selected. Then, the sync pulse becomes a space.
[0040]
In other words, if the generation of some low frequency components is allowed (if the DSV absolute value is allowed to increase slightly), the sync pulse can be arbitrarily selected as a mark or a space.
[0041]
Usually, the synchronization information: SY is sufficiently short with respect to the recorded information, so that the generation of some low frequency components due to the forced selection of the synchronization information is in a sufficiently acceptable range.
Note that the synchronization information code to be selected is selected from codes originally prepared (which satisfy the modulation rule), so the information recorded according to the embodiment of the present invention does not cause a disturbance of the modulation rule.
That is, it can be demodulated by a playback device having a normal decoder.
[0042]
On the other hand, the DVD-R has one pre-pit indicating a synchronization signal in a groove wobbled in advance at a predetermined constant frequency (wobble frequency fw) and one of the lands adjacent to the groove (in this embodiment, the outer peripheral side). Are formed for each sync frame (hereinafter, this pre-pit is particularly referred to as “sync pre-pit”), and 0 to 2 pre-pits are formed to indicate address information and the like.
[0043]
As shown in FIG. 3, the sync frame 2 indicated by the pre-pit constitutes one pair of an even-numbered sync frame (hereinafter referred to as “EVEN frame”) and an odd-numbered sync frame (hereinafter referred to as “ODD frame”). Normally, the prepit is arranged at the position of the EVEN frame, but if it is expected that the prepit is arranged on both adjacent lands, it is arranged shifted to the ODD frame in order to avoid mutual interference. The
[0044]
That is, the pre-pit is arranged only in one of the EVEN frame and the ODD frame constituting the pair.
A pre-pit associated with another groove is formed on the other adjacent (inner peripheral side) land.
[0045]
Further, the wobble frequency: fw is 8 times the sync frame frequency, and the pre-pits are arranged so as to be positioned substantially at the tops of the first three wobbles in one sync frame.
The first prepit is the sync prepit.
[0046]
Note that the length of the prepit in the track direction is preferably as small as possible within the detectable range in order to reduce the influence on the detection of the reproduction signal, and is often formed with a length of several T.
[0047]
When recording data on a DVD-R, the synchronization information: SYNC is synchronized with the prepit so that the sync pulse (record mark or space with a length of “14T”) in SY is positioned adjacent to the sync prepit. Recorded.
At this time, the pre-pit signal is a reference for controlling the recording position so that the recording can be accurately and synchronously recorded.
[0048]
Accordingly, the detection accuracy of the pre-pit signal is important. This is not only during recording, but also the detection accuracy during reproduction of a track that has already been recorded during additional recording or rewriting.
[0049]
FIG. 4A is a schematic diagram showing the relationship between the DVD-R in which information is recorded in synchronization with the prepit and the prepit signal.
The sync prepit 6 is recorded so that sync pulses (recorded marks with hatching in the figure) 7 are adjacent to each other, but since the recording data portion is adjacent to the prepit 8 other than the sync prepit 6, "3T" To “11T” recording marks or spaces are recorded adjacent to each other.
[0050]
A portion indicated by a dotted line in the pre-pit signal is a pre-pit signal at the time of non-recording, and this also occurs when a sufficiently long space (for example, a sync pulse) is recorded with respect to the pre-pit 8.
[0051]
As described above, the prepit signal: Spit binarized by a constant slice level Vth causes phase fluctuations when a recording mark is formed on an adjacent track. In particular, in the prepit 8 other than the sync prepit 6. The phase fluctuates depending on the recording information.
[0052]
On the other hand, FIG. 4B is a schematic diagram showing the relationship between the prepit signal during the recording of information in synchronization with the prepit and the recording power of the light source.
Here, for the sake of simplicity, it is assumed that a space is formed when the light source has a power of P1, and a mark is formed when the light source has a power of P2.
[0053]
While the period during which the irradiated light beam is applied to the sync prepit 6 is constant power (P1 or P2), the power is changed during the period applied to the prepit 8 other than the sync prepit 6, so that the binarized prepit Signal: Spit changes in phase depending on recording information.
[0054]
Further, as described above, when recording by the multi-pulse recording method, not only the pre-pits 8 other than the sync pre-pit 6, but also the sync pre-pit 6, the pre-pit signal: Spit during formation of the recording mark is set. It is extremely difficult to detect with high accuracy.
[0055]
Therefore, the recording position control is preferably performed by the sync prepit 6.
Furthermore, the sync pulse adjacent to the sync prepit 6 is more preferably a space.
[0056]
Next, the overall configuration and operation of the information recording apparatus as an embodiment of the present invention will be described.
The information recording apparatus of this embodiment generates synchronization information so that the sync pulse adjacent to the sync prepit becomes a space for the DVD-R, and performs accurate recording position control based on the synchronization information.
[0057]
FIG. 1 is a block diagram showing the overall configuration of an information recording apparatus according to an embodiment of the present invention.
This information recording apparatus is an apparatus such as a DVD-R drive incorporating a microcomputer including a CPU, a ROM, a RAM, and the like.
[0058]
A controller 13 including interface means with a pickup (PU) 10, laser drive means 11, encoder 12, an external host computer or the like (not shown), a spindle motor 14 for rotating a recording medium, and servo means 15 And a reproduction signal processing means 16.
[0059]
Further, the decoder 17, the pre-pit signal detection means 18, the pre-pit signal decoder 19, the rotation control means 20, the wobble signal detection means 21, the recording clock signal generation means 22, the pre-pit position signal detection means 23, and the recording position Control signal generation means 24 and synchronization information instruction means 25 are provided.
[0060]
The pickup 10 includes a laser that is a light source, a light receiving means, and the like, condenses the light beam emitted from the laser on the DVD-R1, and converts the reflected light from the DVD-R1 into a light reception signal.
[0061]
The laser driving means 11 controls and drives the laser light quantity to a desired value, and modulates the laser based on the recording data: Wdata at the time of recording. At this time, modulation is performed using the recording clock signal: Swck as a reference signal.
[0062]
The encoder 12 uses the recording clock signal: Swck as a reference signal, performs ECC processing, 8-16 modulation processing, interleaving processing, and the like on the data to be recorded input from the controller 13 to generate recording data: Wdata.
At this time, recording data: Wdata is output in accordance with the recording position control signal to start recording.
The detailed configuration of the encoder 12 is shown in FIG.
[0063]
The controller 13 is connected to a host computer via an interface, exchanges data with the host computer, and controls the entire DVD-R.
[0064]
The servo means 15 controls to irradiate an arbitrary position of the DVD-R 1 with the light beam from the pickup 10 based on the servo signal.
[0065]
The reproduction signal processing means 16 processes a light reception signal from the pickup 10 and generates a reproduction signal, a servo signal, and a push-pull signal: Spp.
As is well known here, the push-pull signal is a difference signal between the two-divided light receiving element output by receiving the reflected light from the DVD-R1 by the light receiving element divided into two parallel to the track tangential direction.
[0066]
FIG. 2 is a diagram illustrating an example of the waveform of the push-pull signal: Spp.
As shown in the figure, the push-pull signal: Spp is a signal in which a wobble signal and a prepit signal are superimposed.
[0067]
The pre-pit component is a pre-pit in which pre-pits formed on the inner and outer peripheral lands adjacent to the scanning groove appear up and down, and the upper pre-pit 4 in the figure is associated with the groove. This pre-pit appears when the wobble is almost maximum.
[0068]
Among them, the leading pre-pit is a sync pre-pit 4s, which usually appears every two sync frames.
However, when the shift between the EVEN frame and the ODD frame is switched, the interval may be 1 or 3 sync frames.
[0069]
On the other hand, the lower prepit 5 in the figure is a prepit associated with another groove. In this way, the phase with respect to the wobble changes every moment.
Note that the push-pull signal: Spp is a signal obtained by performing processing such as gain adjustment (for example, adjustment by a light reception sum signal) of a difference signal of the output of the light receiving element divided into two so that signal processing at the subsequent stage is easy. There may be.
[0070]
Furthermore, the push-pull signal: Spp may be a signal after the DC component is suppressed by HPF (abbreviation of “High Pass Filter”).
Then, the push-pull signal offset can be removed.
[0071]
The decoder 17 decodes the reproduction signal to generate a demodulated signal and outputs it to the controller.
[0072]
The pre-pit signal detection means 18 generates a pre-pit signal: Spit from the push-pull signal: Spp. A push-pull signal: Spp and a predetermined threshold value: Vthpit (see FIG. 2) are used for comparison.
[0073]
The pre-pit signal decoder 19 obtains address information and the like pre-formatted on the DVD-R 1 by decoding the pre-pit signal: Spit, and outputs it to the controller 13.
[0074]
The rotation control means 20 controls the rotation of the DVD-R1 so that the wobble signal: Swbl has a predetermined frequency, and the spindle motor 14 rotates the DVD-R1 based on this control signal.
Although a wobble signal is used here, prepits are also formed at a predetermined interval, and may be used.
[0075]
The wobble signal detecting means 21 extracts the wobble signal from the push-pull signal: Spp by BPF (abbreviation of “Band Pass Filter”) and detects the wobble signal: Swbl.
[0076]
The recording clock signal generation means 22 generates a recording clock signal: Swck based on a wobble signal: Swbl, a prepit signal: Spit, or a prepit position signal: Sspit, or a combination thereof. Signal processing is performed based on this recording clock signal: Swck.
Usually, it is configured by a so-called PLL (abbreviation of “Phase Locked Loop”) circuit.
[0077]
The pre-pit position signal detection means 23 detects a pre-pit position signal: Sspit that is a highly accurate detection of the position of the pre-pit from the push-pull signal: Spp. Like the pre-pit signal detection means 18, the pre-pit position signal: Spp is a predetermined value. It can be constituted by a comparator or the like that compares the threshold value.
[0078]
Therefore, some or all of them can be shared with the pre-pit signal detection means 18, but in FIG. 1, they are shown as separate means in order to clarify the gist of the present invention.
[0079]
Even with a simple comparator with a constant slice level, at least the position of the sync prepit can be detected with high accuracy according to the embodiment of the present invention.
[0080]
Alternatively, only the sync prepit may be extracted to generate a prepit position signal.
Further, it is more suitable if the configuration can detect the position with higher accuracy.
[0081]
The recording position control signal generating means 24 generates a recording position control signal synchronized with the prepit position signal: Sspit in accordance with a recording start instruction or a recording start address instruction from the controller 13 and outputs it to the encoder 12.
[0082]
Here, if a frame synchronization signal: Sfs phase-synchronized with the pre-pit position signal is generated by a PLL circuit or the like, and a recording position control signal is generated based on the frame synchronization signal: Sfs, even if the pre-pit position signal is erroneously detected due to noise or the like. The recording position can be indicated.
[0083]
The synchronization information instruction means 25 generates a synchronization information instruction signal for instructing the encoder 12 so that the sync pulse (pulse of “14T” width) included in the synchronization information: SY becomes a space.
[0084]
Next, the internal configuration and operation of the encoder 12 will be described.
FIG. 5 is a block diagram showing the configuration of the encoder 12 and related parts shown in FIG.
[0085]
The encoder 12 includes a data preprocessing unit 30, an 8/16 modulation unit 31, an NRZI conversion unit 33, a synchronization information selection unit 34, a first synchronization information generation unit 35, and a second synchronization information generation unit 36. It consists of.
[0086]
As described above, the processing in the encoder 12 is based on the recording clock signal: Swck, and the start of output of the recording data: Wdata is controlled by the recording position control signal output from the recording position control signal generating means 24.
[0087]
The data preprocessing means 30 performs ECC processing, interleaving processing, and the like of the recording information input from the controller 13.
[0088]
The 8/16 modulation means 31 modulates the recording information that has been subjected to the data preprocessing in accordance with a predetermined modulation rule, and the first information output from the first synchronization information generation means 35 by the synchronization information selection means 34. Synchronization information: SYa and second synchronization information output from the second synchronization information generating means 36: Synchronization information selected from SYb: SY is added for each sync frame. At this time, as described above, the modulation is performed so that the low-frequency component is suppressed.
[0089]
Normally, this synchronization information: SY is selected from a plurality of codes in order to select a code that satisfies the modulation rule at the connection portion with the previous sync frame and to suppress a low frequency component.
Depending on the low-frequency component suppression condition, when selecting from any code, it is determined whether the sync pulse becomes a recording mark or a space.
[0090]
The NRZI conversion means 33 performs NRZI conversion of the modulation code output from the 8/16 modulation means 31 and converts it into a recording pulse train (recording data: Wdata).
[0091]
The synchronization information selection means 34 selects either the first synchronization information: SYa or the second synchronization information: SYb and outputs it to the 8/16 modulation means 31.
Here, as described above, even if the first synchronization information: SYa is forcibly selected, there is no serious problem. The selection is performed by a synchronization information instruction signal generated by the synchronization information instruction means 25.
[0092]
The first synchronization information generating means 35 generates first synchronization information: SYa in which a code is selected so that the sync pulse is a space.
On the other hand, the second synchronization information generating means 36 generates the second synchronization information: SYb, and determines whether the sync pulse becomes a space or a recording mark from the low frequency component suppression condition.
[0093]
Next, the process of the synchronization information selection unit 34 will be described in detail.
As is clear from the above description, when the first synchronization information: SYa is selected, a highly accurate pre-pit position signal can be reliably obtained, and highly accurate recording position control can be performed.
[0094]
In addition, when the second synchronization information: SYb is selected, the low frequency component of the recording pulse is suppressed, but the sync pulse of the mark may continue in some cases. It is insufficient to obtain a position signal.
[0095]
By the way, sync prepits are not adjacent to all synchronization information, and it is possible to generate a highly accurate recording position control signal even if accurate prepit position signals cannot be detected in all sync prepits. .
[0096]
That is, for example, when a frame synchronization signal: Sfs that is phase-synchronized with the pre-pit position signal is generated by a PLL circuit or the like, and a recording position control signal is generated based on the signal, the pre-pit position signal is sufficiently spaced in the control band of the PLL circuit. Can be obtained, it is possible to generate a highly accurate recording position control signal.
[0097]
Therefore, if the sync pre-pit and the space sync pulse do not coincide with each other for a predetermined number of frames, the first synchronization information: SYa is selected, and the pre-pit position signal is reliably detected. The synchronization information: SYb may be selected.
[0098]
By selecting synchronization information in this way, prepit position signals can be obtained at intervals sufficient for high-precision recording position control, and most other frame synchronization information conforms to low-frequency component suppression conditions. Therefore, the influence of the low frequency component suppression effect reduction can be almost ignored.
[0099]
Further, when the second synchronization information: SYb is generated, if the low frequency component suppression effect by the synchronization information, that is, if the absolute value of the DSV is the same or within a predetermined range, the sync pulse becomes a space. Even if synchronization information is preferentially selected, the low-frequency component suppression effect is hardly reduced, and in addition, since the coincidence of sync prepits and space sync pulses increases, many highly accurate prepit position signals can be obtained and recorded. Position control accuracy is also improved.
[0100]
Next, even when additional recording or overwriting is performed on a pre-recorded recording medium, if the pre-pit position of the pre-recorded area can be accurately detected as described above, accurate recording position control can be performed.
[0101]
Therefore, the pre-recording may be performed by the same method as described above, and the recording medium pre-recorded in such a manner can be suitably and accurately controlled in the recording position in the information recording apparatus, and is linked to record unnecessary data. The area can be made smaller or unnecessary, and the recording area of the recording medium can be used effectively.
[0102]
  In addition,In the above recording mediumThe DVD-R, which is a write-once optical disc, has been described. However, the present invention can also be applied to a recording medium such as a rewritable optical disc using a phase change material as a recording layer, and is based on other recording layer materials. Needless to say, it can also be applied.
[0103]
  Also in the preformat format, prepits were formed on a wobbled track (groove or land) and one or both of the tracks (land or groove) adjacent to the track.The above effects if applied to recording mediaIs similarly obtained.
  Further, it may be preformatted only by prepits (no wobble).
[0104]
The information recording apparatus of this embodiment is located adjacent to the prepit so that an accurate prepit position signal can be reliably detected even during recording or in an already recorded area by the function according to claim 1 of the present invention. Synchronous information that creates a space in the sync pattern and sync information that suppresses the low-frequency component of the recording pulse train are generated, and one of them is selected, enabling accurate recording position control with a simple configuration And the influence of the low frequency component suppression effect reduction can be reduced.
Therefore, the linking area for recording unnecessary data can be made smaller and unnecessary, and the recording area can be used effectively.
[0105]
In the information recording apparatus of this embodiment, the recording position control signal generating means generates a recording position control signal based on a part of the pre-pit position signal by the function related to claim 2 of the present invention. If it is located adjacent to a part of the pre-pits that will be the basis for generating the position control signal, select the synchronization information that makes the synchronization pattern a space, otherwise, select the synchronization information that suppresses the low-frequency component of the recording pulse train. Since the selection is made, a highly accurate pre-pit position signal can be obtained at necessary and sufficient intervals, so that the recording position can be reliably controlled and the influence of the low-frequency component suppression effect can be reduced.
[0106]
  further,the aboveThe recording medium has prepits formed at predetermined intervals in an area between information recording tracks, records information in advance on all or a part of the information recording track, and a synchronization pattern is adjacent to at least a part of the prepit. Is recorded such that at least a part of the synchronization pattern located adjacent to the pre-pit is a space synchronization pattern. It is possible to use the recording area effectively by using less and unnecessary linking area for recording.
[0107]
  further,the aboveThe recording medium comprises prepits composed of sync prepits formed at intervals corresponding to the predetermined information unit or an integer multiple thereof and information prepits indicating address information, etc., and positioned adjacent to the sync prepits. Since at least one of the predetermined units is a space in the synchronization pattern to be performed, the linking area for recording unnecessary data is reduced and unnecessary even when performing additional writing and rewriting, and the recording area is effectively used. It is possible to reduce the effect of reducing the low-frequency component suppression effect of data recorded in advance.
According to this recording medium, high-precision recording is performed when prepits are formed at predetermined intervals in an area between information recording tracks, and additional recording or overwriting is performed on a recording medium prerecorded on a part or all of the information recording tracks. Position control can be performed.
[0108]
【The invention's effect】
As described above, according to the information recording apparatus of the present invention, when information is recorded on a recording medium in which prepits are formed at predetermined intervals in an area between information recording tracks, the prepit signal detected from the prepits is used. In an information recording apparatus for controlling the recording position, it is possible to control the recording position with high accuracy, to make the recording area effective by using less or unnecessary linking area for recording unnecessary data, and further Can prevent an increase in the low frequency component of the recording pulse train.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of an information recording apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram showing an example of a waveform of a push-pull signal: Spp generated by the reproduction signal processing means 16 shown in FIG.
FIG. 3 is a diagram schematically showing the arrangement of wobbles and pre-pits on a DVD-R.
FIG. 4 is a schematic diagram showing the relationship between information recorded on a DVD-R in synchronization with a pre-pit signal and the pre-pit signal.
FIG. 5 is a block diagram showing an internal configuration of the encoder shown in FIG. 1;
[Explanation of symbols]
1: DVD-R 2: Sync frame
3: Leading area 4, 5: Pre-pit
4s, 6: Sync pre-pit
7: Sync pulse 8: Pre-pit
10: Pickup (PU)
11: Laser driving means 12: Encoder
13: Controller 14: Spindle motor
15: Servo means 16: Reproduction signal processing means
17: Decoder
18: Pre-pit signal detection means
19: Pre-pit signal decoder
20: Rotation control means
21: Wobble signal detection means
22: Recording clock signal generation means
23: Pre-pit position signal detection means
24: Recording position control signal generating means
25: Synchronization information instruction means 30: Data preprocessing means
31: 8/16 modulation means 33: NRZI conversion means
34: Synchronization information selection means
35: First synchronization information generating means
36: Second synchronization information generating means

Claims (2)

When recording information in which synchronization information for synchronizing every predetermined information unit is recorded on a recording medium having prepits formed at predetermined intervals in an area between information recording tracks, the synchronization information is In an information recording apparatus that includes a synchronization pattern that is sufficiently longer than a prepit, and performs recording so that the synchronization pattern is positioned adjacent to at least a part of the prepit.
First synchronization information generating means for generating first synchronization information such that the synchronization pattern becomes a space;
Second synchronization information generating means for generating second synchronization information for suppressing low frequency components of the recording pulse train;
Synchronization information selection means for selecting and outputting either the first synchronization information or the second synchronization information;
Prepit position signal detection means for detecting a prepit position signal indicating the position of the prepit;
A recording position control signal generating means for generating a recording position control signal based on the pre-pit position signal;
While inserting the first synchronization information or the second synchronization information selected by the synchronization information selection means, a modulation code obtained by modulating the recording information according to a predetermined modulation rule is converted into a recording pulse train, and according to the recording position control signal An information recording apparatus comprising: encoding means for starting output of the recording pulse train. The recording position control signal generating means is provided with means for generating a recording position control signal based on a part of the pre-pit position signal,
The synchronization information selection means selects the first synchronization information when the synchronization pattern is located adjacent to a part of the pre-pits serving as a reference for generating the recording position control signal, and the second synchronization information otherwise. 2. An information recording apparatus according to claim 1, further comprising means for selecting information.

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