JP4244978B2 - Optical information recording apparatus, optical information recording method, optical disc manufacturing method, and optical information recording medium - Google Patents

Description

  The present invention relates to an optical information recording device, an optical information recording method, and an optical information recording medium. For example, as a compact disc (CD) or digital video disc (DVD) recording device, a CD or DVD recording method, or a CD or DVD disc Can be applied. In the recording apparatus and the recording method of the present invention, information such as music and video signals is recorded on the optical disc by turning on and off the recording laser according to a method defined by the CD and DVD standards. At the same time, by gradually changing the output of the recording laser, it is possible to record the second information not defined in the standard such as CD and DVD on the same disk.

  In addition, in the optical information recording medium of the present invention, new information that can be confirmed by visually observing the disc is recorded in addition to, for example, music and video signals defined in the CD and DVD standards.

  For example, according to the patent application filed on July 16, 1996 (Japanese Patent Application No. 8-205292) filed by the same applicant, the edge of the reproduction signal is corresponding to all the recorded signal patterns. The amount of deviation from the ideal position is obtained and a table is created. Jitter can be eliminated by changing the edge position of the recording signal according to the pattern of the recording signal and recording, using this table. Second information that is not included in the CD standard can be recorded in a superimposed manner.

  Further, according to a patent application filed on March 5, 1997 (Japanese Patent Application No. 9-67843), an ID pattern such as a bar code with a watermark pattern is recorded on the lead-in or signal recording portion of the optical disk. By detecting the pattern electrically, the disk ID or cipher can be read to prevent copying or piracy.

  According to a patent application filed on October 3, 1997 (Japanese Patent Application No. 9-298328), the polar coordinates of the radius (track number) and the rotational speed (number of FG pulses) indicating the position during cutting are shown. By providing a circuit for converting to Cartesian coordinates in real time, it is possible to perform cutting using data represented in the Cartesian coordinate system as it is. Of course, these optical disc apparatuses simultaneously record EFM (Eight-to-Fourteen Modulation) modulated signals defined by the compact disc standard, in addition to information such as characters and graphics. Therefore, it can be played back by a conventional player, and characters and figures are recorded in the signal portion of the disc, thereby making it possible to manufacture a disc with increased added value.

  However, the above-described conventional method is configured to record second information such as characters and graphics as a change in laser output. For this reason, there is a possibility that the signal characteristics may fluctuate at the boundary portion where the laser output changes, and therefore, the laser output change cannot be made very large. As a result, there is a problem that the second information such as recorded characters and graphics is not very clear.

  The optical information recording apparatus and optical information recording method of the present invention have been made in consideration of the above points, and can record second information such as characters and figures to be recorded on the disk as a large laser output difference. As a result, clear second information can be recorded. Moreover, since the optical information recording medium of the present invention can increase the change in the pit width due to the second information, the second information can be confirmed more clearly.

In order to solve this problem, the optical information recording apparatus of the present invention is in accordance with modulation signal generating means for generating a modulation signal that changes in accordance with the first information, and second information that is visually recognized as a pattern such as a character or a figure. and time varying signal producing means for producing a time varying signal which varies with time, the time and amount changing means for changing the amount of records over the follow change signal, off in accordance with a modulation signal of the laser light obtained by the light amount changing means The time-varying signal generating means generates a time-varying signal so that the output voltage changes in a stepwise manner with time, and the laser light obtained by the light modulating means is recorded on the disk. By irradiating the recording medium, the second information is represented by the change in the pit width, and the light intensity of the laser beam is changed so as to make the change stepwise. Unishi Te and records on the disk-shaped recording medium first and second information as the same pit rows.

  The optical information recording apparatus of the present invention operates as follows. The modulation signal generating means operates to generate a modulation signal that changes according to the first information. The time change signal generating means operates to generate a time change signal that changes with time according to the second information. The light amount changing means acts to change the light amount of the laser according to the time change signal. The light modulation means acts to turn on and off the laser light obtained by the light quantity changing means in accordance with the modulation signal. Thereby, it acts so that the change of the laser light quantity by the second information is performed gradually.

  Furthermore, the modulation signal generating means includes first modulation signal generating means for generating the first modulation signal by switching the signal level in a cycle that is an integral multiple of a predetermined basic period according to the first information, Change pattern detection means for detecting a change pattern of one modulation signal, timing correction means for correcting the change timing of the first modulation signal according to both the time change signal and the change pattern, and producing a second modulation signal Configured so that the change timing of the recording signal is corrected in accordance with both the change in the laser light quantity and the change pattern of the recording signal.

In the optical information recording method of the present invention, the first information is recorded mainly by turning on and off the laser beam, and the second information that is visually recognized as a pattern such as a character or a figure is mainly emitted from the laser beam. The intensity is recorded by changing the output voltage using a time-varying signal so that the output voltage changes stepwise with time, and the light intensity of the laser beam changes gradually over time. To do.

  The optical information recording method of the present invention operates as follows. The first information acts to record mainly by turning on and off the laser beam. Also, the second information is recorded mainly by changing the light intensity of the laser beam. This acts so that the light intensity change of the laser beam is performed gradually.

  Furthermore, the timing for turning on and off the laser beam is adjusted according to both the first information and the light intensity of the laser beam.

In the optical information recording medium of the present invention, the first information is recorded mainly by changing the length and position of the pits, and the second information visually recognized as a pattern such as a character or a figure is the main information. The width of the pit is recorded by changing the width of the pit using a time-varying signal such that the output voltage changes stepwise with time.

  Also, the optical information recording medium of the present invention operates as follows. The first information mainly acts to be recorded by changing the length and position of the pits. Further, the second information mainly acts to be recorded by changing the width of the pit. Thereby, the change of the pit width by the second information acts in a stepwise manner.

  Further, the change in the pit width by the second information is made in stages. Further, the length and position of the pit are finely adjusted by the signal pattern recorded as the pit and the width of the pit.

  An optical information recording apparatus according to the present invention includes a modulation signal generating unit that generates a modulation signal that changes in accordance with first information, and a time change signal generating unit that generates a time change signal that changes in time according to second information. And a light amount changing means for changing the light amount of the laser in accordance with the time change signal, and a light modulating means for turning on and off the laser light obtained by the light amount changing means in accordance with the modulation signal. It is configured to change slowly. Accordingly, in the optical information recording apparatus of the present invention, for example, in addition to information (first information) such as music and video defined in standards such as CD and DVD, the first information not defined in standards such as CD and DVD. 2 information can be recorded on the same disc. In addition, the optical disc manufactured by the optical information recording apparatus of the present invention has the effect that the reproduction signal characteristic does not change suddenly near the change point of the second information, and stable reproduction is possible. Play.

  Further, the modulation signal producing means of the optical information recording apparatus of the present invention generates a first modulation signal by switching the signal level at a cycle that is an integral multiple of a predetermined basic cycle according to the first information. And a change pattern detecting means for detecting a change pattern of the first modulation signal, correcting a change timing of the first modulation signal in accordance with both the time change signal and the change pattern, And a timing correction unit that generates the second modulation signal, and is configured to correct the change timing of the recording signal in accordance with both the change in the laser light quantity and the change pattern of the recording signal. Therefore, the optical characteristics recorded on the optical information recording apparatus of the present invention have very good signal characteristics. In addition, it is possible to set a larger amount of change in the optical output for recording the second information, and as a result, it is possible to record clear second information.

  In the optical information recording method of the present invention, the first information is recorded mainly by turning on and off the laser beam, and the second information is recorded mainly by changing the light intensity of the laser beam. The light intensity of the laser beam is gradually changed over time. Further, the timing for turning on and off the laser beam is adjusted according to both the first information and the light intensity of the laser beam. Therefore, the optical information recording method of the present invention is not defined in the standard of CD, DVD, etc. in addition to the information (first information) such as music and video defined in the standard of CD, DVD, etc. The second information can be recorded on the same disc. Further, it is possible to set a larger amount of change in the optical output for recording the second information, and as a result, it is possible to record clear second information.

  In the optical information recording medium of the present invention, the first information is recorded mainly by changing the length and position of the pit, and the second information is recorded mainly by changing the width of the pit. Has been. Further, the change in the pit width by the second information is made in stages. Further, the length and position of the pit are finely adjusted by the signal pattern recorded as the pit and the width of the pit. Therefore, for example, in addition to information (first information) such as music and video defined in standards such as CD and DVD, a medium on which second information not defined in standards such as CD and DVD is recorded. Can be obtained. By recording visually identifiable graphic information such as characters and graphics in the signal portion of the disk as the second information, there is an effect of enabling a disk with increased added value. Further, the graphic information of the optical information recording medium according to this patent has an effect that it can be clearly confirmed as compared with the conventional method.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
FIG. 1 is a block diagram showing an optical disc recording apparatus 1 according to an embodiment of the present invention. This optical disk recording apparatus 1 records the audio data SA output from the digital audio tape recorder 3 by exposing the disk master 2. In the manufacturing process of the optical disc, the master disc 2 is developed and then electroformed to produce a mother disc, and a stamper is produced from the mother disc. Further, in the manufacturing process of the optical disk, a disk-shaped substrate is prepared from the stamper thus prepared, and a reflective film and a protective film are formed on the disk-shaped substrate to form a compact disk.

  That is, in this optical disc recording apparatus 1, the spindle motor 14 rotates the disc master 2 and outputs an FG signal FG whose signal level rises at every predetermined rotation angle from the FG signal generation circuit held at the bottom. The spindle servo 13 drives the spindle motor 14 so that the frequency of the FG signal FG becomes a predetermined frequency according to the exposure position of the disk master 2, thereby rotating the disk master 2 under the condition that the linear velocity is constant. .

  The FG signal is also connected to the orthogonal coordinate position detection circuit 5. The Cartesian coordinate position detection circuit 5 counts the FG signal to output the currently recorded position as position information X and Y in the Cartesian coordinates.

  The position information X and Y are connected to the character signal generation circuit 6. The character signal generation circuit 6 is configured, for example, as a ROM (Read Only Memory), and is configured with X and Y as address inputs and a signal SE as an output. From this circuit, corresponding to the current recording position, information of characters and figures (second information) that can be confirmed when the disk surface is visually observed is generated as a signal SE.

  The second information SE obtained in this way is input to the staircase waveform generation circuit 7. The staircase waveform generation circuit 7 detects a change in the second information SE, and creates a 3-bit staircase signal SF whose output value changes stepwise with time. The staircase signal SF is converted by the voltage conversion circuit 15 into a signal SX having a staircase voltage and input to the optical modulator 10A. Similarly, the staircase signal SF is also input to the timing correction circuit 8.

  The recording laser 9 is composed of a gas laser or the like, and emits a laser beam L1 for disc master exposure. The optical modulator 10A and the optical modulator 10B are configured by electroacoustic optical elements. The optical modulator 10A changes the output of the laser beam L1 in accordance with a staircase signal SF whose voltage changes in a staircase pattern in accordance with character or graphic information SE. That is, when the second information SE has been maintained at level 1 for a long time, the laser beam L1 is passed so that the output of the laser beam L2 becomes 100%. On the contrary, when the second information SE has been maintained at level 0 for a long time, the laser beam L1 is attenuated and passed so that the output of the laser beam L2 becomes 85%. When the second information SE transitions from level 0 to level 1, the laser beam L1 is changed stepwise from 85% power to 100% power. Similarly, when the second information SE transitions from level 1 to level 0, the laser beam L1 is changed stepwise from 100% power to 85% power.

  The optical modulator 10A outputs the laser beam L2 whose optical output varies between 100% and 85% by following the output SF of the staircase waveform generation circuit 7 as described above. Next, the laser beam L2 thus obtained is turned on / off by the optical modulator 10B. That is, when the signal SC from the timing correction circuit 8 is level 1, the laser beam L3 is turned on. Conversely, when the signal SC is level 0, the laser beam L3 is turned off.

  The mirror 11 bends the optical path of the laser beam L3 and emits it toward the disc master 2, and the objective lens 12 condenses the reflected light of the mirror 11 on the disc master 2. The mirror 11 and the objective lens 12 are sequentially moved in the outer circumferential direction of the disk master 2 in synchronization with the rotation of the disk master 2 by a thread mechanism (not shown), whereby the exposure position by the laser beam L3 is sequentially moved to the outer periphery of the disk master 2. Displace in the direction.

  As a result, in the optical disk recording apparatus 1, a spiral track is formed by the movement of the mirror 11 and the objective lens 12 while the disk master 2 is rotationally driven, and the modulation signal SC and the character / graphic information SE are formed on this track. Corresponding pits are formed sequentially.

  The modulation circuit 4 receives the audio data SA output from the digital audio tape recorder 3 and adds the corresponding subcode data to the audio data SA. Further, the modulation circuit 4 processes the audio data SA and the subcode data in accordance with a compact disc format, and generates a modulation signal SB. That is, the modulation circuit 4 adds an error correction code to the audio data SA and subcode data, and then performs interleaving processing and EFM modulation processing. As a result, the modulation circuit 4 outputs an EFM modulation signal SB whose signal level changes with a period (period 3T to 11T) that is an integral multiple of the basic period T of the pit formation.

  In a conventionally used optical disk recording apparatus, the EFM modulation signal SB produced in this way is sent to the optical modulator 10B as it is, and the light beam obtained from the laser 9 is turned on / off to be exposed on the optical disk master 2. Was done.

  In a disc manufactured by such a conventional method, the state of the reproduction signal changes depending on the pattern of the recording signal, which causes jitter. As a specific example, in a disc recorded by a conventional optical disc recording apparatus, a phenomenon has been observed in which a pit having a minimum size corresponding to a 3T signal is always recorded smaller than an ideal size. . For this reason, when the signal from the pit corresponding to the 3T signal is observed after binarization at a predetermined slice level, the pulse width is observed to be slightly shorter than 3T, which causes jitter.

  Furthermore, the conventional method has a problem that when the recording laser power fluctuates, the optimum binarization level in the reproduction signal also fluctuates. For this reason, as shown in the present embodiment, when the laser power is changed between 100% and 85% according to the character / graphic information SE, the player must change the binarization level according to the laser power. There was a problem of having to. In the case where the binarization level fluctuation in the reproducing apparatus does not go well for some reason, an error occurs in the conventional method, and such a recording method is impossible.

  Therefore, in the present embodiment, the output signal SB of the modulation circuit 4 is sent to the timing correction circuit 8. In the timing correction circuit 8, a change pattern of the EFM modulation signal SB is detected. At the same time, the staircase signal SF is sent to the timing correction circuit 8. Therefore, the timing correction circuit 8 can perform timing correction in accordance with information on both the change pattern of the EFM signal SB being recorded and the laser power being recorded.

  The timing correction circuit 8 outputs a modulation signal SC in which the edge position is finely adjusted according to both of the two types of information obtained in this way. That is, in the timing correction circuit 8, the change timing of the output signal SC is changed so that the laser power during recording (value from 85% to 100%) and the change pattern of the EFM signal SB during recording (pit length and space length are 3T to 11T). The modulation signal SC is finely adjusted in accordance with both of the above and the modulation signal SC so that the jitter is always the best.

  That is, when the modulated signal SC that has passed through the timing correction circuit 8 is recorded with a predetermined laser power represented by the staircase signal SF and the resulting disc is reproduced, the reproduced signal is reproduced at a predetermined binarization level VL. When binarized, a signal containing no jitter is obtained.

  Incidentally, the staircase signal SF is a signal created from the second information SE. The second information SE can be configured as a signal that forms characters and figures when the information recorded on the disk is observed visually. Therefore, in the disc recorded according to the present embodiment, the width of the pits changes according to the second information SE, and as a result, the information of characters and figures can be observed by visually observing the disc surface.

  Furthermore, in this embodiment, the laser power changes slowly, and appropriate correction is always performed by the timing correction circuit 8 corresponding to the changing laser power. However, it is possible to obtain a reproduction signal without deteriorating jitter. Further, the change in laser power can be made larger than before, and as a result, information on characters and figures that can be visually observed more clearly than before can be recorded on the disk surface.

  In addition, since all the recording laser powers are always corrected by the timing correction circuit 8, the problem that the pits are slightly different for each pattern is eliminated, and the jitter of the reproduction signal is comprehensively reduced. Discs can be created. In the present embodiment, since the edge position is adjusted for each recorded pattern, it is possible to remove jitter depending on the pattern, that is, jitter due to intersymbol interference.

  FIG. 2 is a block diagram showing the timing correction circuit 8. In the timing correction circuit 8, the PLL circuit 16 generates a channel clock CK from the EFM modulation signal SB and outputs it. Accordingly, in the modulation signal SB, the signal level changes in a cycle that is an integral multiple of the basic cycle T, so that the PLL circuit 16 changes the channel clock in which the signal level changes in accordance with the basic cycle T synchronized with the modulation signal SB. CK is generated and supplied to the rising edge correction circuit 17A and the falling edge correction circuit 17B.

  As shown in FIG. 3, the rising edge correction circuit 17A connects thirteen latch circuits 19A to 19M operating in accordance with the clock CK in series, and inputs the EFM modulation signal SB to the series circuit. As a result, the rising edge correction circuit 17A samples the EFM modulation signal SB at the timing of the channel clock CK, and detects the change pattern of the EFM modulation signal SB from the sampling results of 13 consecutive points. That is, for example, when a latch output of “0001111000001” is obtained, it can be determined that the pattern is a change pattern in which a pit having a length of 4T continues after a space having a length of 5T. Similarly, when a latch output of “0011111000001” is obtained, it can be determined as a change pattern in which a pit having a length of 5T continues after a space having a length of 5T.

  The correction value table 20 is formed of a read-only memory storing a plurality of correction data, and latch outputs of the latch circuits 19A to 19M are inputted as lower 13 bits of the address. A staircase signal SF is input as the upper 3 bits of the address. The staircase signal SF reflects the optical power of the laser that is currently recording. That is, the correction value table 20 outputs correction value data DF corresponding to both the change pattern of the modulation signal SB and the recording power. The monostable multivibrator (MM) 21 receives a latch output from the central latch circuit 19G among the 13 latch circuits connected in series, and receives a latch output for a predetermined period (see FIG. During a period sufficiently shorter than the period 3T), a rising pulse signal whose signal level rises is output.

  The delay circuit 22 has 15 stages of tap outputs, and the delay time difference between the taps is set to the timing signal resolution correction resolution in the edge position correction circuit 17A. The delay circuit 22 sequentially delays the rising pulse signal output from the monostable multivibrator 21 and outputs it from each tap. The selector 23 selectively outputs the tap output of the delay circuit 22 according to the correction value data DF, and thereby selectively outputs the rising pulse signal SS having a delay time changed according to the correction value data DF.

  That is, the rising edge correction circuit 17A rises in response to the rise of the signal level of the EFM modulation signal SB, and the delay time of each rising edge with respect to the EFM modulation signal SB changes the change pattern and recording of the EFM modulation signal SB. A rising edge signal SS that changes according to the laser power inside is generated.

  As described above, the rising edge correction circuit 17A detects the pit pattern formed on the optical disc and the laser power during recording in the range of the period 12T with the basic period T as a unit. Then, the rising edge signal SS is generated according to the recording pattern and the laser power during recording.

  The falling edge correction circuit 17B is the same as the rising edge correction circuit 17A except that the monostable multivibrator 21 operates based on the falling edge of the latch output and the content of the correction value table 20 is different. Composed.

  That is, the falling edge correction circuit 17B also detects the pit pattern formed on the optical disk and the laser power during recording in the range of the period 12T with the basic period T as a unit, and the laser according to the pattern and power is detected. The falling edge signal SR is generated by correcting the timing of the falling edge of the modulation signal SB that is the timing of the end of beam irradiation.

  The flip-flop (F / F) 18 shown in FIG. 2 combines and outputs the rising edge signal SS and the falling edge signal SR described above. That is, the flip-flop 18 inputs the rising edge signal SS and the falling edge signal SR to the set terminal S and the reset terminal R, respectively, so that the signal level rises at the rising edge of the rising edge signal SS and then falls. A modulation signal SC whose signal level falls at the rise of the signal level of the edge signal SR is generated.

  Thereby, in the EFM modulation signal SB, the timing of the rising edge and the falling edge is output as a signal SC corrected according to the recording pattern (determined by the length of the pit and space) and the recording power.

  Based on the output signal SC of the timing correction circuit 8 obtained as described above, the laser beam L2 whose output level changes between 100% and 85% is controlled to be turned on / off by the optical modulator 10B to obtain the laser beam L3. The optical disc master 2 is irradiated.

  FIG. 4 shows a configuration of the orthogonal coordinate position detection circuit 5 used when generating the second information SE recorded as described above. In the figure, the one-turn count circuit 30 and the track count circuit 31 are cleared at the start of recording by a clear pulse CLR from a system controller (not shown), and their initial values are zero. As for the FG signal from the spindle motor 14, for example, 4200 pulses are output every time the spindle motor 14 makes one rotation. This pulse is counted 4200 by the one-rotation counter 30 and output as a count value RX. The count value RX takes a value from 0 to 4199, and is incremented by one count every time the spindle motor 14 rotates by 1/4200, and thus represents the rotation angle of the spindle motor 14. Further, when the spindle motor 14 rotates once, this counter is reset. Each time this reset occurs, a pulse is generated as a signal RT, and this pulse is input to the track counter 31.

  The track count circuit 31 outputs the track number TK currently being recorded by counting the signal RT of one pulse per rotation. For example, when recording a compact disc (CD), recording starts from a radius of 23 mm, and recording is performed at a track pitch of 1.6 microns up to a radius of 58 mm. Therefore, the value of the track count circuit 31 is from 0 to about 22000 counts. Change.

  As described above, the count value RX of the one-turn count circuit 30 and the count value TK of the track count circuit 31 correspond to angle information and radius information when the currently recorded position is expressed in polar coordinates. Therefore, the coordinate conversion circuit 32 can calculate and output the position information X and Y in the orthogonal coordinate system using these two values. The position information X and Y in the orthogonal coordinate system is sent to the character signal generation circuit 6 after being converted in this way.

  The orthogonal coordinate position detection circuit 5 is realized by the configuration shown in FIG. 5, for example. In this figure, input ports 34 and 35 are connected to the CPU 33, and output ports 36 and 37 are simultaneously connected. The count values RX and TK of the one rotation count circuit 30 and the track count circuit 31 are connected to the input ports 34 and 35, respectively, and the CPU 33 can take in the respective values.

  The CPU 33 calculates the position information X and Y in the orthogonal coordinate system from these two values according to the following equations 1 and 2, and outputs them to the output ports 36 and 37.

[Expression 1] X = A · (TK · Tp + Tb) · cos (2π · (RX / 4200)) + B

[Expression 2] Y = A · (TK · Tp + Tb) · sin (2π · (RX / 4200)) + B

  Here, A and B are constants determined by the size and position of the coordinate system, Tb represents the recording start radius, and Tp represents the track pitch. As a result of the above conversion, the position information represented in the polar coordinate system (RX, TK) as shown in FIG. 6A is converted into the orthogonal coordinate system (X, Y) as shown in FIG. 6B.

  The character signal generation circuit 6 is composed of a ROM (read only memory) or the like, and outputs (X, Y) of the orthogonal coordinate position detection circuit 5 as address inputs, and outputs the memory output as character or graphic information SE. It is made like that. For example, when it is desired to draw a pattern as shown in FIG. 7A on the disk, the pattern as shown in FIG. 7B is recorded in the memory inside the character signal generation circuit 7.

  As described above, the image to be drawn is binarized using the orthogonal coordinate system and recorded in the ROM inside the character signal generation circuit 6. Since the information recorded in the ROM is input after the coordinate system is converted in real time by the orthogonal coordinate position detection circuit 5, it is read as it is and is sequentially recorded on the disk as a change in the recording laser power. However, when the output of the character signal generation circuit 6 changes from level 0 to level 1 or from level 1 to level 0, the staircase waveform generation circuit 7 generates a staircase waveform SF so as to smooth the change. Generate.

  FIG. 8 is a block diagram showing the configuration of such a staircase waveform generation circuit 7. In this figure, the change of the second information SE from the level 0 to the level 1 is detected by the rising edge detection circuit 40 and supplied to the up / down counter 42 as a signal UP whose level is 1 for a certain time. While the up signal input UP is at level 1, the up / down counter 42 counts the reference clock FK from the reference oscillator 43 and counts up the output value SF. When the second information SE changes from level 1 to level 0, it is detected by the falling edge detection circuit 41 and supplied to the up / down counter 42 as a signal DN whose level is 1 for a certain period of time. . While the down signal DN is at level 1, the up / down counter 42 counts the reference clock FK from the reference oscillator 43 and counts down the output value SF. The rising edge detection circuit 40 and the falling edge detection circuit 41 that perform such an operation can be configured by, for example, a monostable multivibrator or the like.

  An example of the operation of the staircase waveform generation circuit 7 having the above-described configuration will be described with reference to FIGS. When the rising edge of the second information SE as shown in FIG. 9A occurs, a pulse that becomes level 1 only during time T as shown in FIG. 9B is output from the rising edge detection circuit 40. The up / down counter 42 counts up at the cycle of the reference clock FK as shown in FIG. 10E and sequentially increases the count value SF from 0 to 7. Although not shown, the up / down counter 42 is configured to stop further counting up to prevent overflow when the count value becomes 7.

  When the falling edge of the second information SE as shown in 10A occurs, a pulse as shown in FIG. 10B is output from the falling edge detection circuit 41. In this case, the up / down counter 42 counts down at the cycle of the reference clock FK as shown in FIG. 10E, and sequentially decreases the count value SF from 7 to 0 as shown in FIG. 10C. Although not shown, the up / down counter 42 is configured to stop further count down when the count value reaches 0 to prevent underflow.

  As described above, a step signal SF whose value sequentially changes from 0 to 7 with the change of the second information SE is obtained at the output of the up / down counter 42. Such a staircase signal SF is converted into an analog voltage for controlling the optical modulator 10A by the voltage conversion circuit 15 whose configuration is shown in FIG. For example, as shown in FIG. 9D or FIG. 10D, the signal SX converted into the analog voltage has a stepped waveform in which the value is gradually changed near the change point of the second information SE.

  In the voltage conversion circuit 15 whose configuration is shown in FIG. 11, the staircase signal SF is connected as an address signal of a read-only memory (ROM) 44. In the ROM 44, it is calculated and recorded in advance what value the laser recording power should take in response to the staircase signal SF from 0 to 7. As the simplest example, an example in which the laser power described in the first half of the present embodiment is changed from 100% to 85% will be described. For example, when the value of the staircase signal SF is 7, 100% of the laser power is expected, so that a numerical value 100 is recorded corresponding to the address 7. When the staircase signal SF corresponds to 0, 85% of the laser power is expected, so the numerical value 85 is recorded. When the staircase signal SF is between 1 and 6, a value calculated from proportional distribution between 100 and 85 is recorded.

  Of course, the above example is a case where it is assumed that 100% power is output when the output of the ROM 44 is 100. Actually, it is necessary to determine a value to be recorded in the ROM 44 in consideration of the conversion gain of the D / A converter 45 and the conversion efficiency of the optical modulator 10A. Further, the output power of the laser and the input voltage to the optical modulator 10A may not be in a linear relationship. In such a case, it is necessary to record an appropriately changed value in the ROM 44.

  The laser output value read from the ROM 44 as described above is converted as an analog voltage value SX by the D / A converter 45 and supplied to the optical modulator 10A to control the output power of the laser 9. Has been made. The laser beam L2 thus obtained has a stepwise change in the output power according to the staircase signal SF. (See FIG. 9D and FIG. 10D)

  FIG. 12 is a process diagram for explaining generation of a correction value table 20 used for edge timing correction. The correction value table 20 exists in both the rising edge correction circuit 17A and the falling edge correction circuit 17B. By setting these tables correctly, even when the recording laser power changes in accordance with the graphic or character information SE, the reproduction signal crosses a predetermined slice level at the correct timing synchronized with the clock CK (ie, the jitter level). It is possible to produce a disk with a small number of discs.

  These correction value tables 20 have the same generation method except that the generation conditions are different. Accordingly, only the rising edge correction circuit 17A will be described below.

  In the process described below, a disc master for evaluation is created by the optical disc apparatus 1, and the correction value table 20 is set based on the reproduction result of the compact disc created from this disc master.

  Here, at the time of creating the disc master for evaluation, a correction value table 20 for evaluation criteria is set in the optical disc apparatus 1. The evaluation reference correction value table 20 is formed by setting the correction value data DF so that the selector 23 shown in FIG. 3 always selects and outputs the center tap output of the delay circuit 22. As a result, in this step, the timing correction circuit 8 is set to have no effect.

  In this way, the signal SC having no effect of the timing correction circuit 8 is sent to the optical modulator 10B, and the master disc 2 is exposed with the laser beam L2 of 100% power in the same manner as in the production of a normal compact disc. .

  After developing the disk master 2 exposed in this way, a mother disk is created by electroforming, and a stamper 50 is created from this mother disk. Further, a compact disc 41 is produced from this stamper 40 in the same manner as in a normal compact disc producing process.

  In FIG. 12, the CD player 52 reproduces the evaluation compact disc 51 created as described above in accordance with an instruction from the computer 54. At this time, the CD player 52 is controlled by the computer 54 to switch the operation, and the reproduction signal RF whose signal level changes according to the amount of return light obtained from the compact disc 51 is output to the digital oscilloscope 53 from the built-in signal processing circuit. To do.

  At this stage, the binarization level of the reproduction signal is not always predetermined as in a normal compact disc. Also, jitter is observed because pit shaping is not perfectly ideal.

  The digital oscilloscope 53 performs analog-digital conversion processing on the reproduction signal RF at a sampling frequency 20 times the channel clock, and outputs the resulting digital signal to the computer 54.

  The computer 54 controls the operations of the CD player 52 and the digital oscilloscope 53 and also processes the digital signal output from the digital oscilloscope 53, thereby calculating the correction value data DF.

  Finally, the computer 54 drives the ROM writer 55 to sequentially store the calculated correction value data DF in the read-only memory, thereby forming the correction value table 20. The optical disk is finally manufactured by using the correction value table 20 thus completed.

  FIG. 13 is a flowchart showing a processing procedure for creating the correction value data DF in the computer 54. In this processing procedure, the computer 54 proceeds from step SP1 to step SP2, and sets the jitter detection result Δr (p, b) and the jitter measurement count n (p, b) to the value 0. Here, the computer 54 calculates the jitter detection result Δr (p, b) for each combination of the pit length p and the pit interval b before and after the edge to be detected for jitter, and the jitter measurement count n (p, b). ). For this reason, in step SP2, the computer 54 sets all these jitter detection results Δr (p, b) and the number of jitter measurements n (p, b) to initial values.

  Subsequently, the computer 54 proceeds to step SP3, and compares the digital signal output from the digital oscilloscope 53 with a predetermined slice level VL to generate a digital binarized signal obtained by binarizing the reproduction signal RF. In this process, the computer 44 binarizes the digital signal so that the value above the slice level is 1 and the value 0 is below the slice level.

  Subsequently, the computer 54 proceeds to step SP4, and generates a reproduction clock from the binarized signal composed of this digital signal. Here, the computer 54 simulates the operation of the PLL circuit by arithmetic processing based on the binarized signal, and thereby generates a reproduction clock.

  Further, in the subsequent step SP5, the computer 54 samples the binarized signal at the timing of each falling edge of the reproduction clock generated in this way, and decodes the modulated signal (hereinafter, this decoded modulated signal is decoded). Called the decoded signal).

  Subsequently, the computer 54 proceeds to step SP6 to detect the time difference e from the time of the rising edge of the binarized signal to the time of the falling edge of the reproduction clock closest to this edge, and thereby the jitter at this edge is determined. Time measurement. Subsequently, in step SP7, the computer 54 detects the pit length p and the pit interval b before and after the decoded signal for the edge timed in step SP6.

  Subsequently, in step SP8, the computer 54 adds the time difference e detected in step SP6 to the jitter detection result Δr (p, b) corresponding to the pit length p and the pit interval b before and after, and the corresponding jitter. The measurement number n (p, b) is incremented by a value 1. Subsequently, the computer 54 proceeds to step SP9, determines whether or not the time measurement has been completed for all rising edges, and returns a step SP5 when a negative result is obtained.

  As a result, the computer 54 repeats the processing procedure of steps SP5-SP6-SP7-SP8-SP9-SP5, cumulatively adds the time-measured jitter detection results for each change pattern appearing in the reproduction signal RF, and counts the number of additions. To do. This change pattern corresponds to a period of 6 samples before and after the reference period T from the edge of the jitter detection target so as to correspond to the number of stages of the latch circuits 19A to 19M in the rising edge correction circuit 17A (a period of 12T as a whole). ).

  When the jitter time measurement is completed for all the edges in this way, the computer 54 moves to step SP10 when an affirmative result is obtained in step SP9. Here, for each change pattern appearing in the reproduction signal RF, the computer 54 Average the measured jitter detection results. That is, since the jitter detected in step SP6 is affected by noise, the computer 54 averages the jitter detection results in this way, and improves the jitter measurement accuracy.

  After averaging the jitter detection results in this way, the computer 54 proceeds to step SP11 and can generate correction value data DF for each change pattern from the detection results. Here, the correction value data DF is calculated by executing the arithmetic processing of the following formula 3 with τ being the delay time difference between taps in the delay circuit 22.

[Equation 3] Hr1 (p, b) = Hr0 (p, b) −a / τ · Δr (p, b)

  Here, Hr1 (p, b) is a tap of the delay circuit 22 selected by the correction value data DF, and a value of 0 is a center tap. Hr0 (p, b) is a tap of the delay circuit 22 selected by the correction value data DF which is an initial value. In this embodiment, Hr0 (p, b) is set to a value of 0. It will be. A is a constant. Here, in this embodiment, a is set to a value of 1 or less (for example, 0.7), so that the correction value data is surely converged even if there is an influence of noise or the like.

  When the computer 54 stores the correction value data DF thus generated in a predetermined address area of the ROM writer 55, the computer 54 proceeds to step SP12 and ends this processing procedure. Subsequently, the computer 54 executes the same processing procedure for different recording powers. After executing the above processing for all the powers (eight kinds of power corresponding to the staircase signal SF of 0 to 7), the ROM writer 55 burns in to complete the correction value table 20 in the rising edge correction circuit 17A. Let

  Further, the same processing is executed for the falling edge of the digital binarized signal, thereby completing the correction value table 20 in the falling edge correction circuit 17B.

  Using the correction value table 20 thus completed, the optical disc is manufactured in the optical disc apparatus 1. In the optical disc thus completed, even when the recording power is changed stepwise according to the second information SE, the pit has an ideal length according to the change of the power, and the jitter is extremely small over the entire disc surface. Is played.

  In the above-described embodiment, the case where an optical disk for evaluation is produced for all the eight levels of recording power and the correction value table is directly calculated from the reproduction signal has been described. However, the present invention is not limited to this, and for example, evaluation The optical disk for use may be limited to only two different recording powers, and the correction value table for other recording powers may be created by mathematical operation such as interpolation or extrapolation.

  Further, in the above-described embodiment, the case where the jitter amount is measured by the time measurement of the binary signal based on the basic clock and the correction value data is generated from the measurement result has been described. However, if sufficient accuracy can be ensured in practice, the correction value data may be generated by detecting the signal level of the reproduced signal based on the basic clock instead of measuring the jitter amount by this time measurement. . In this case, an error voltage from the signal level of the detected reproduction signal to the slice level is calculated, and correction value data is calculated from the error voltage and the transient response characteristic of the reproduction signal.

  In the above-described embodiment, the case where the timing of the modulation signal is corrected according to the correction value data tabulated has been described. However, the present invention is not limited to this, and in the case where sufficient accuracy can be secured in practice, detection is performed in advance. Instead of the correction value data, the correction value data may be calculated by arithmetic processing, thereby correcting the timing of the modulation signal.

  In the optical information recording apparatus of the present embodiment described above, the modulation circuit 4 constitutes a modulation signal generating means for generating a modulation signal SB that changes in accordance with the first information SA, and the staircase waveform generation circuit 7 A time change signal creating means for creating a time change signal SF that changes with time according to the second information SE is configured, and the optical modulator 10A constitutes a light quantity changing means for changing the light quantity of the laser according to the time change signal SF, Each of the optical modulators 10B constitutes optical modulation means for turning on and off the laser light L1 obtained by the light quantity changing means 10A according to the modulation signal SB.

1 is a block diagram showing a configuration of an optical disc device according to an embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of a timing correction circuit of the optical disc apparatus of FIG. 1. FIG. 3 is a block diagram showing a configuration of a rising edge correction circuit in the timing correction circuit of FIG. 2. FIG. 2 is a block diagram illustrating a configuration of an orthogonal coordinate position detection circuit in the optical disc recording apparatus of FIG. 1. FIG. 5 is a block diagram showing a configuration of a coordinate conversion circuit in the orthogonal coordinate position detection circuit of FIG. 4. 6A and 6B are diagrams showing a state of coordinate transformation in the coordinate transformation circuit of FIG. 5, FIG. 6A is a diagram showing position information in a polar coordinate system, and FIG. 6B is a diagram showing position information in an orthogonal coordinate system. 7A and 7B are diagrams for explaining the operation of the character signal generation circuit in FIG. 1. FIG. 7A is a diagram showing a pattern to be drawn on a disk, and FIG. 7B is a diagram showing a pattern recorded in a memory inside the character signal generation circuit. It is a block diagram explaining the structure of the staircase waveform generation circuit in FIG. FIG. 9A is a timing diagram for explaining the count-up operation of the staircase waveform generation circuit in FIG. 8, FIG. 9A shows the second information SE, FIG. 9B shows the up signal UP, FIG. 9C shows the count value SF, and FIG. FIG. FIG. 10A is a timing diagram for explaining the countdown operation of the staircase waveform generation circuit in FIG. 8, FIG. 10A is the second information SE, FIG. 10B is the down signal DN, FIG. 10C is the count value SF, FIG. 10D is the analog voltage signal SX, FIG. FIG. 4 is a diagram illustrating reference clocks FK. It is a block diagram which shows the structure of the voltage conversion circuit in FIG. FIG. 7 is a process diagram illustrating a correction value table creation process in the optical disc apparatus of FIG. 1. It is a flowchart which shows the process sequence of the computer in the process of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Optical disk apparatus, 2 ... Disc master, 3 ... Digital audio tape recorder, 4 ... Modulation circuit, 5 ... Cartesian coordinate position detection circuit, 6 ... Character signal generation circuit, 7 ... Staircase waveform Generation circuit, 8 ... Timing correction circuit, 9 ... Laser, 10A, 10B ... Optical modulator, 11 ... Mirror, 12 ... Objective lens, 13 ... Spindle servo circuit, 14 ... Spindle motor, 15 ... ... Voltage conversion circuit, 17A ... Rising edge correction circuit, 17B ... Falling edge correction circuit, 51 ... Compact disc, 52 ... CD player, 53 ... Digital oscilloscope, 54 ... Computer

Claims (5)

In an optical information recording apparatus for recording second information visually recognized as a pattern such as a character or a figure on a disc-shaped recording medium using a laser beam in addition to the first information used for recording,
Modulation signal generating means for generating a modulation signal that changes in accordance with the first information;
Time-varying signal creating means for creating a time-varying signal that changes with time according to the second information;
A light amount changing means for changing the light amount of the laser according to the time change signal;
It is composed of light modulation means for turning on and off the laser light obtained by the light quantity changing means according to the modulation signal,
The time-varying signal creating means creates the time-varying signal so that the output voltage becomes a signal that changes stepwise with time, and applies the laser beam obtained by the light modulating means to the disk-shaped recording medium. By irradiating, the second information is represented by a change in the width of the pit, and the light intensity of the laser beam is changed so as to make the change stepwise. An optical information recording apparatus, wherein information is recorded on the disc-shaped recording medium as the same pit row. Optical information recording in which pits are formed and recorded by irradiating an optical recording medium with second information visually recognized as a pattern such as characters and figures in addition to the first information used for recording. In the method
Recording the first information mainly by turning on and off the laser beam;
The second information is recorded mainly by changing the light intensity of the laser beam using a time-varying signal such that the output voltage becomes a signal that changes stepwise with time,
The second information is represented by a change in the width of the pit, and the light intensity of the laser beam is changed so as to make the change stepwise, and recording is performed on the optical recording medium. Optical information recording method. First information and second information visually recognized as a pattern of characters, figures, etc. are recorded as a pit row, and the recorded information is read by irradiating the pit row with a laser beam condensed by a lens. In an optical information recording medium adapted to be
The first information is recorded mainly by changing the length and position of the pit,
The second information is recorded mainly by changing the width of the pit using a time-varying signal such that the output voltage becomes a signal that changes stepwise with time,
The optical information recording medium is characterized in that the light intensity of the laser beam is changed so that the pit width is changed stepwise by the second information. In addition to the first information used for recording, the second information, which is visually recognized as a pattern of characters, figures, etc., is generated by a master exposure process in which pits are formed and recorded by optically modulating the laser beam and irradiating it on the optical disk In an optical disc manufacturing method for manufacturing an optical disc using a master disc to be manufactured,
The first information is recorded mainly by turning on and off the laser beam, and the second information is mainly a signal in which the light intensity of the laser beam changes its output voltage stepwise with time. Recording is performed by using such a time change signal, and the second information is represented by a change in the width of the pit, and the light intensity of the laser beam is changed so as to make the change stepwise. And an exposure process of the master to be recorded on the optical disc,
After developing the master, by performing electroforming, a mother disk creating step for creating a mother disk;
A stamper creating step for creating a stamper from the mother disk;
An optical disk manufacturing method comprising: forming a disk-shaped substrate from the stamper, and forming a reflective film and a protective film on the disk-shaped substrate to form an optical disk. In an optical information recording medium in which first information that is binarized and information is read and second information that is visually recognized as a pattern such as a character or a graphic are recorded.
A first region having the first information;
And a second region having the first information and the second information,
The second information is obtained by changing the width of the pit representing the first information in the second region by using a time change signal such that the output voltage becomes a signal that changes stepwise with time. Represents
The optical information recording medium is characterized in that the change in the pit width is changed stepwise between a target value of the first pit width and a target value of the second pit width.

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