JP2009283095A - Optical disk device, signal processing lsi, laser driver, and optical information recording method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide stable recording performance in high speed recording by decreasing the number of transmission lines from a conventional transmission method and by circumventing deterioration of recording performance due to transmission line properties at increase of the recording speed, when recording pulse information is transmitted to a laser driver on an optical pickup in an optical disk. <P>SOLUTION: The number of transmission signals is decreased, by encoding laser pulse information on multi-levels transmitted by a laser driver. Furthermore, skew restriction between bits is reduced by using a gray code for encoding. Then, encoding is performed by using status transition, occurrence of short pulses in a transmission line is reduced by switching status transition by a recording mark and a space. Additionally, compatibility for the correspondence for complex laser pulse information and correspondence for high-speed recording can be attained, by transmitting through switching of the existence and the absence of encoding. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser driving method for generating a laser pulse train for optically recording information on a recording medium, an integrated circuit that realizes the laser driving method, and an optical disc apparatus on which the integrated circuit is mounted.

  When information is recorded on an optical disk using laser light, information recording is performed by forming a recording mark on the disk recording film with a laser pulse train. The laser pulse train used at that time is called a recording strategy.

  The recording strategy information is composed of a laser pulse power level (hereinafter referred to as power level) and a pulse emission timing (hereinafter referred to as pulse timing). These parameters need to be optimized according to the recording conditions such as the type of the optical disk, the length of the recording marks and the interval (space), and the recording speed.

In an optical disk apparatus, a laser is driven using a laser driving circuit (hereinafter referred to as a laser driver) mounted on a pickup based on recording strategy information to generate a laser pulse. The setting method of the recording strategy information to the laser driver is roughly divided into the following two.
(1) In the signal processing LSI mounted on the main board of the device, the power level information necessary for the recording and the pulse timing information corresponding to the power level are generated from the mark and space information (NRZ information) recorded on the optical disk. Then, they are sequentially transmitted to a laser driving circuit on the pickup through means such as a flexible cable to generate a laser pulse train.
(2) Marks and space information (NRZ information) to be recorded on the optical disk are transmitted from the signal processing LSI mounted on the main board of the apparatus onto the pickup via means such as a flexible cable, and each information is transmitted from the information to the inside of the laser driver. A laser pulse train is generated by generating power level information and pulse timing information.

  The configurations of (1) and (2) are described in detail in the following patent documents.

JP-A-8-147697 Japanese Patent Laid-Open No. 11-283249

In the above (1), since the circuit inside the laser driver mounted on the pickup has a simple configuration including only the drive current generation circuit and its switch circuit, it is possible to suppress the heat generation of the pickup that leads to deterioration in recording performance. However, there are the following problems.
(a) Since transmission of pulse timing information is limited by characteristics such as a flexible cable, it becomes difficult to generate pulses with a minute time interval as the recording speed increases.
(b) As the power level increases, it is necessary to transmit pulse timing information corresponding to the power level, and the number of transmission lines such as flexible cables increases. Especially for pulse timing information, differential transmission by LVDS (Low Voltage Differential Signaling) is used for stable high-speed transmission. In this case, the increase in transmission lines is doubled.
(c) When a pulse is generated by adding a plurality of pulse powers, it is necessary to manage a shift in pulse timing information between pulses to be added, so-called skew.

On the other hand, in (2), since the transmission line is only NRZ or NRZ and the recording reference clock for determination thereof, the transmission line such as a flexible cable can be reduced. Further, since the pulse timing information is transmitted only inside the laser driver on the pickup, the problems (a) and (c) of the above (1) can be avoided and the recording speed can be increased. However, there are the following problems.
(a) Since the NRZ mark, space length determination, power level, and pulse timing information are generated inside the laser driver on the pickup, the circuit processing is complicated, the heat generation of the pickup is increased, and the recording performance is deteriorated. It becomes.
(b) The circuit configuration of the laser driver becomes complicated for the same reason as described above, and the device cost increases as compared with the method (1) in which power level information and pulse timing information can be built in the main-base signal processing LSI. .

  The present invention solves the above problems and makes it possible to cope with an increase in recording speed in signal transmission between a signal processing LSI for generating a recording strategy and a laser driver driven thereby. As a result, it becomes possible to manufacture an optical disk apparatus that can increase the recording speed by using the signal processing LSI and the laser driver. Further, the number of signals on the signal transmission path can be reduced, and an inexpensive optical disc apparatus can be manufactured.

  An object of the present invention is to provide a mark and space length discriminating circuit for discriminating a mark length and a space length on a recording medium from information recorded on the recording medium in an optical disc apparatus that records information on a recording medium using a pulse train generated by laser emission. A laser pulse train generating circuit that determines the shape of the laser pulse train from the output of the mark and space length discriminating circuit, and a plurality of binary values indicating the change timing of the laser emission amount based on the laser pulse train output from the laser pulse train generating circuit A change timing signal generation circuit that outputs a change timing signal based on a pulse train, an encode circuit that converts the plurality of change timing signals into a code signal based on a predetermined conversion table, and outputs the code signal, and the code signal based on a predetermined conversion table Change to multiple laser emission level change timing signals. Based on the decoding circuit and a plurality of change timing signal output from the decoder circuit, it is solved by the optical disk apparatus characterized by comprising a laser drive circuit for generating a laser driving current which forms a laser pulse train.

In addition, in the optical disc apparatus that records information on a recording medium using a pulse train generated by laser emission, the above-described problem is a mark / space length discriminating circuit that discriminates a mark length and a space length on the recording medium from information recorded on the recording medium. A laser pulse train generation circuit that determines the shape of the laser pulse train from the output of the mark length and the space length discrimination circuit, and a plurality of binary values that indicate the change timing of the laser emission amount based on the laser pulse train output from the laser pulse train generation circuit A change timing signal generation circuit that outputs a change timing signal based on a pulse train of the signal, an encode circuit that converts the plurality of change timing signals into code signals based on a predetermined conversion table, and a laser output from the laser pulse train generation circuit The above change timing based on the pulse train A first switch circuit for switching a plurality of change timing signals output from the signal generation circuit and a code signal output from the encoding circuit to output to the signal transmission path, and a code signal input via the signal transmission path Transmitted from the change timing signal generation circuit via the transmission path based on the laser pulse train output from the decode circuit and the laser pulse train generation circuit that convert the laser light emission amount change timing signals based on a predetermined conversion table Based on the output of the second switch circuit which switches and outputs the plurality of change timing signals output from the decode circuit and the plurality of change timing signals output from the decoding circuit, the laser drive current for forming the laser pulse train is generated An optical disc comprising a laser driving circuit In the apparatus, when the shape of the laser pulse train generated by the laser pulse train generation circuit is a predetermined shape, the first switch circuit outputs a code signal output from the encoding circuit to the signal transmission path; and Performing the encoding process in the encoding circuit, the decoding process in the decoding circuit, and the selection of outputting a plurality of change timing signals output from the decoding circuit to the laser driving circuit in the second switch circuit, In other cases, the first switch circuit outputs a plurality of change timing signals output from the change timing signal generation circuit to the signal transmission path. The second switch circuit outputs the change timing signals from the change timing signal generation circuit. Select to output multiple change timing signals to the laser drive circuit It is solved by.

  In addition, the above-described problem includes a state transition circuit that performs state transition based on a laser pulse train generated by the laser pulse train generation circuit in the optical disc apparatus having the above configuration, and outputs a change timing by the encode circuit. Either one or both of the conversion table used for converting the signal and the code signal and the conversion table used for converting the code signal and the change timing signal in the decoding circuit are changed based on the state output of the state transition circuit. Is solved.

  In addition, in the optical disc apparatus that records information on a recording medium using a pulse train generated by laser emission, the above-described problem is a mark / space length discrimination circuit that discriminates a mark length and a space length on the recording medium from information recorded on the recording medium. A laser pulse train generation circuit that determines the shape of the laser pulse train from the output of the mark length and the space length discrimination circuit, and a plurality of binary values that indicate the change timing of the laser emission amount based on the laser pulse train output from the laser pulse train generation circuit A change timing signal generation circuit for outputting a change timing signal based on a pulse train, a state transition circuit for performing state transition based on a laser pulse train used for recording information on the recording medium, and a state of the state transition circuit Based on the output, the state of the plurality of change timing signals is set to a predetermined code An encoding circuit that allocates and outputs as a code signal, a decoding circuit that changes the code signal into a plurality of laser emission amount change timing signals based on the state output of the state transition circuit, and a plurality of changes that are output from the decoding circuit The invention is solved by an optical disc apparatus comprising a laser drive circuit that generates a laser drive current for forming a laser pulse train based on a timing signal.

  Further, the above problem is solved in the optical disk apparatus having the above-described configuration by making the code signal a multi-value signal composed of two or more bits and continuously changing the multi-value signal as one bit. The

  In addition, in the optical disk apparatus having the above-described configuration, when the multilevel signal changes with an arbitrary bit, the next change of the multilevel signal is realized by a bit different from the arbitrary bit. The

  In the optical disc apparatus having the above-described configuration, the time interval of the signal change of the same bit in the multi-level signal is set to one period or more of the recording clock synchronized with the recording data recorded on the recording medium. It is solved by.

  The present invention solves the above problems and makes it possible to cope with an increase in recording speed in signal transmission between a signal processing LSI for generating a recording strategy and a laser driver driven thereby. As a result, it becomes possible to manufacture an optical disk apparatus that can increase the recording speed by using the signal processing LSI and the laser driver. Further, the number of signals on the signal transmission path can be reduced, and an inexpensive optical disc apparatus can be manufactured.

  First, the configuration of the recording strategy and the conventional transmission method will be described with reference to the drawings. FIG. 2 shows an example of a recording strategy and a generation method thereof, and FIGS. 3 and 4 are conventional examples of a block configuration diagram related to an information recording operation of the optical disc apparatus. In FIGS. 3 and 4, blocks having the same functions are given the same figure numbers. 3 corresponds to the method (1) shown in the conventional example, and FIG. 4 corresponds to the method (2).

  When recording data is input from the upper host 318 in FIGS. 3 and 4 to the modulation circuit 316, the modulation circuit 316 in the signal processing LSI 312 receives NRZ (200 in FIG. 2) and a recording clock synchronized with NRZ (201 in FIG. 2). (Hereinafter referred to as CLK) is output. In the configuration of FIG. 3, NRZ and CLK are determined in mark length and space length by a mark / space determination circuit 1201 disposed in the same LSI, and input to the recording strategy generation circuit 315. The recording strategy generation circuit 315 reads the recording strategy information corresponding to the input mark and space information from the recording strategy table memory 314, and generates the recording strategy 203 for recording the recording mark 202 in FIG. The generated recording strategy 203 is decomposed into a waveform indicating the generation timing of each power level and a waveform indicating the timing for switching on / off of a high frequency superimposed waveform (hereinafter referred to as HF). In FIG. 2, pulses Hfon are generated corresponding to the on / off settings of pulses L0 to L3 and HF corresponding to the power levels Pf, Pl, Pm and Ps. Each generated pulse is converted into an LVDS signal by the LVDS transmission circuit 313 and transmitted to the LVDS reception circuit 310 of the laser driver 303 via a transmission path 311 such as a flexible cable. Similarly, the power level corresponding to each pulse is transmitted to the current source circuit 304 of the laser driver 303 via the transmission path 311. In the laser driver 303, a current corresponding to each power level is output from the current source circuit 304, and a high frequency superimposed current is output from the HF generation circuit 309. These current outputs are controlled by the switches 305 to 309 according to the pulses received by the LVDS receiving circuit 310, and current addition is performed to generate a laser driving current to cause the laser 302 to emit light. Record information.

  On the other hand, in the configuration of FIG. 4, NRZ and CLK generated inside the signal processing LSI 408 are input to the LVDS transmission circuit 404, and an LVDS reception circuit in the laser driver 401 via a transmission 403 such as a flexible cable as an LVDS signal. Input to 402. The received NRZ and CLK are determined in mark length and space length by a mark / space determination circuit 407 mounted in the laser driver, and input to the recording strategy generation circuit 405. The recording strategy generation circuit 405 and the recording strategy table memory 406 to which the recording strategy generation circuit 405 refers have the same functions as the functions 315 and 314 in the description of FIG. Since the operation for recording the information on the disk 300 by causing the laser 302 to emit light is the same as that described with reference to FIG. 3, the description thereof is omitted here.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

Embodiment 1
FIG. 1 shows a block diagram relating to an information recording operation of the optical disc apparatus according to the first embodiment of the present invention. In the same figure, blocks having the same functions as those in FIGS. 3 and 4 are denoted by the same reference numerals, and description thereof is omitted. FIG. 5 shows a recording strategy information transmission method according to the present embodiment.

  Hereinafter, recording strategy transmission in the present embodiment will be described with reference to FIGS.

  Based on the recording data from the host 318, the pulse groups L0 to L3 and Hfon generated by the recording strategy generation circuit 315 are input to the encoding circuit 100 as in FIG. If each pulse indicated by L0 to L3 and Hfon represents a state by a bit and a combination thereof, a total of 5 bits and 32 states can be taken. However, in the case of a castle type strategy as shown in FIG. 2, there are six states used when actually generating a recording strategy. As another recording strategy format, there is a strategy using a multi-pulse, but the number of states used for optical disk recording is at most about 8 states. Therefore, the encoding circuit 100 encodes a 5-bit state indicated by a combination of the above pulse groups (hereinafter referred to as recording pulse information) into a 3-bit code. An example of the conversion table at that time is shown in FIG. Since this encoding table reduces the number of states of the recording pulse information, it is necessary to optimize the table depending on the recording strategy format. A conversion table corresponding to each recording strategy is stored in the conversion table memory 101 of FIG. 1, and an optimum conversion table is selected according to a command from the recording strategy generation circuit, and conversion by the encoding circuit 100 is performed. Note that the conversion table stored in the conversion table memory 101 is configured to be programmable by firmware or the like that controls the optical disk apparatus. The converted 3-bit code is converted into an LVDS signal by the LVDS transmission circuit 102. The converted LVDS signal is output from the signal processing LSI 108 and input to the LVDS receiving circuit 105 of the laser driver 104 mounted on the pickup via a transmission path 103 such as a flexible cable. The LVDS signal received by the LVDS receiving circuit is input to the decoding circuit 107. In the decoding circuit 107, a conversion table similar to the conversion table used in the signal processing LSI 108 is read from the conversion table memory 106 in the laser driver, and the recording pulse information of L3 to L3 and Hfon is restored from the input code. In order to realize this processing, the conversion table memory 106 inside the laser driver is configured to be programmable from the microcomputer 318 by firmware or the like for controlling the optical disk device in the same manner as the conversion table memory 101. Register the same contents. The subsequent light emission of the laser 302 and the recording of information on the disk 300 are the same as described with reference to FIG.

  FIG. 7 is a flowchart showing the information recording operation on the optical disc by the above recording strategy transmission. When a recording command and recording data are received from the upper host (701), the recording strategy information of the disc (this is referred to as strategy A) is read from the recording strategy table (702). Next, a conversion table corresponding to the strategy A is set in a conversion table mounted on the signal processing LSI and the laser driver (703). The conversion table is set programmable from a microcomputer by firmware or the like for controlling the optical disk apparatus. Next, the NRZ of the recording data is input from the modulation circuit to the mark / space determination circuit (704), the determination result is input to the strategy generation circuit (705), and recording pulse information is generated (706). The recording pulse information is encoded by the conversion table set in 703 in the encoding circuit inside the signal processing LSI (707) and transmitted to the laser driver (708). The laser driver decodes the received encoding result (709) with the conversion table set in 703 in the decoding circuit to generate recording pulse information (710), outputs a laser pulse train, and executes recording (711,712). .

  In the present embodiment, by encoding the transmission signal between the signal processing LSI and the laser driver, conventionally, the pulse timing information was transmitted as five recording pulse information, but the encoded three pulses are used. Can be transmitted. Thus, by encoding the transmission signal between the signal processing LSI and the laser driver, it is possible to reduce the number of signal lines in the transmission path and to reduce the number of pins of the signal processing LSI and the laser driver LSI.

<< Embodiment 2 >>
FIG. 8 is a diagram showing recording pulse information transmission in the second embodiment of the present invention. In the figure, the same parts as those in FIG. 5 are given the same reference numerals, and the description thereof is omitted here.

  In the present embodiment, a gray code is used for encoding in the first embodiment. The gray code is a code in which a bit change in the state transition is 1 bit when each code value is in a state. FIG. 9 shows the state transition. The main pulse shapes that can be taken by the recording strategy are several types, such as a pulse train using multi-pulses and a castle-type pulse train, both of which are patterned in power level changes in the pulse. It is possible to apply to the state transition by the gray code. For example, in the recording strategy of FIG. 2 shown in the first embodiment, it is possible to transmit recording pulse information in gray code by encoding as in the encoding output of FIG. The conversion table used for encoding at this time is as shown in FIG.

  Reference numerals 801 to 803 denote encode output signal waveforms when the gray code is used. In the gray code, the change in the state transition is always 1 bit, that is, only one signal, so that the change points of the encoded output signal waveforms, that is, the edge timing do not overlap as shown in the figure. As a result, the problem (c) described in the conventional method (1), the phase between bit signals, and the problem of skew management can be solved.

<< Embodiment 3 >>
FIG. 11 shows a diagram of transmission of recording pulse information in the third embodiment of the present invention. This figure is a diagram in the case of performing pulse timing transmission of a recording strategy including multi-pulses by the gray code encoding shown in the second embodiment. The shortest cycle of multipulses in DVD and BD is a reference clock cycle 1Tw of a recording signal. Therefore, when transmitting the recording pulse information of the recording strategy including the multi-pulse, in the method of the conventional example (1), as shown in the broken line 1101 in FIG. 11, the short pulse of the channel clock 1Tw or less at L0 and L1. Transmission is required. However, since a flexible cable or the like serving as a transmission path such as L0 to L3 has a transmission band, it is difficult to transmit these short pulses with the recording speed onto the optical disc. In order to avoid this, the multi-pulse part is configured in the gray code 4 state as indicated by a broken line 1102. Thereby, the shortest pulse width of each pulse of bits 0 to 2 of the gray code can be set to 1 Tw or more. In this way, by setting the transition condition so as not to return to the previous state in the state transition of the gray code, the shortest pulse width of each of the pulses 1104 to 1106 of the bits 0 to 2 of the gray code is set to the pulse time in the recording pulse train 1103. The width can be set to twice or more of the width, and the influence of the band in the transmission path can be reduced.

<< Embodiment 4 >>
However, when it is considered that the recording pulse information is transmitted using the gray code of 3 bits and 8 states as shown in FIG. 11, the transition from each state is limited to 3 states as shown in FIG. If the transition condition is set so as not to return to the previous state in the gray code state transition as described above, the allowable state transition is two states. Furthermore, when the same recording pulse information is assigned to different gray codes as in the above multi-pulse part, for example, there are two types of transitions from Pw to Pb, and transitions to Pc in monopulses (1107 in FIG. 11). (Part) will be transitioned to 3 states, and the above state transition conditions cannot be satisfied.

  A fourth embodiment of the present invention corresponding to the above problem will be described below. In the present embodiment, it is considered to change the state transition according to the number of repetitions of multipulses including the leading and trailing pulses. For example, in the case of a recording strategy including a multi-pulse shown in FIG. 11, as shown in FIG. 13, when the number of multi-pulse repetitions is an even number, the state transition is changed according to an odd number of times and one time (mono pulse). In the figure, each state corresponds to each power level of the recording strategy. The state transition is set so as to follow the transition of a thick line when the number of multipulses is 1 (monopulse), a thin line when the number is even, and a dotted line when the number is odd. This makes it possible to transmit a 3-bit gray code with the recording strategy of FIG. 11 while setting all the pulse time widths to be transmitted to be not less than twice the pulse time width in the recording pulse train. It is possible to reduce both the influence of bandwidth and the number of transmission signal lines and the number of LSI pins.

<< Embodiment 5 >>
FIG. 12 shows a block diagram related to the information recording operation of the optical disc apparatus in the fifth embodiment of the present invention. In the same figure, blocks having the same functions as those in FIG.

  As in the first embodiment, the recording data from the upper host 318 is input into the signal processing LSI 1205, modulated by the modulation circuit 316, and NRZ and CLK are output. These are input to the mark / space determination circuit 1201, and the mark length and space length are determined.

  The determination result of the block is sent to the recording strategy generation circuit 1202 and the gray code encoder 1203. The recording strategy generation circuit 1202 selects the recording strategy information from the recording strategy table memory based on the mark, space information, and medium information, and generates pulse timing information. The pulse timing information is sent to the gray code encoder 1203 and converted into a gray code. At this time, the state transition of the gray code used for the conversion of the pulse train information is selected from the state transition memory 1204. The state transition is selected using the result of the mark / space determination circuit described above. In addition, the state transition stored in the state transition memory is programmably registered from the microcomputer 318 by firmware or the like that controls the optical disc apparatus. The gray code converted from the pulse timing information according to the selected state transition is converted into LVDS by the LVDS transmission circuit 102 and input to the LVDS reception circuit 105 of the laser driver via the transmission path 103 such as a flexible cable. . The received gray code is converted by the gray code decoder 1207.

  On the other hand, the power level information of the recording strategy generated by the above-described strategy generation circuit inside the signal processing LSI 1205 is converted into power level information corresponding to each gray code via the gray code encoder 1203, and the current source setting of the laser driver 1206 is set. It is output to the circuit 1208. The current source setting circuit 1208 sets a current value corresponding to the power level in the current source 1209 corresponding to each gray code of the current source circuit 1209. As a method for setting the power level, for example, a method of setting current source selection with address information, setting the current value as a digital value using the current source circuit 1209 as a DAC (Digital Analog Converter), and the like can be considered. Each output of the current source circuit 1209 is output to a switch group 1210 corresponding to each gray code. The switch group 1210 is configured such that the current corresponding to each gray code and the gray code value decoded by the gray code decoder 1207 described above have a one-to-one correspondence. As a result, the current value corresponding to the gray code value is selected by the switch 1210 and output to the laser 302. With this configuration, the pulse timing transmission in the above-described fourth embodiment is realized.

  FIG. 19 is a flowchart showing the information recording operation on the optical disc in the present embodiment. When a recording command and recording data are received from the host host (1901), the recording strategy information of the disc (referred to as strategy A) is read from the recording strategy table (1902). Next, the state transition group corresponding to the strategy A is stored in the state transition memory mounted on the signal processing LSI and the laser driver (1903). The state transition group is a group in which different state transitions according to NRZ marks and spaces are collected for the same recording strategy. The state transition group is programmably registered in the state transition memory from the microcomputer by firmware or the like that controls the optical disk device. Next, the NRZ of the recording data is input from the modulation circuit to the mark / space determination circuit (1904), and the determination result is sent to the strategy generation circuit and the gray code encoder (1905). The strategy generation circuit generates recording pulse information and power level information from the determination result (1907). The gray code encoder encodes the recording pulse information into a gray code (1908) based on the recording pulse information output from the strategy generation circuit and the state transition (1906) selected from the mark / space determination result. The encoding result is transmitted to the laser driver (1909), and the switch group inside the laser driver is controlled (1911). On the other hand, the power level information generated by the strategy generation circuit is set in the current source setting circuit of the laser driver based on the state transition group (1912). From the current output by the switch control and the current source setting circuit, a laser pulse train is output and recording is performed (1913, 1914).

  In this method, any recording can be performed by changing the correspondence between the state transition registered in the state transition memory 1204 in the signal processing LSI internal 1205 and the gray code set in the current source setting circuit 1208 in the laser driver 1206 and the power level. It is possible to realize the encoding to the gray code by the state transition with respect to the strategy.

  In the fifth embodiment, when the encoding of the third embodiment is adopted, the pulse time width of the gray code transmitted between the signal processing lSI and the laser driver is set to the transmission characteristic of a transmission line such as a flexible cable. Therefore, it is possible to omit the LVDS transmission circuit 105 and the LVDS reception circuit 105 in FIG. 12 and transmit a gray code as a normal binarized signal.

  Also, depending on the recording strategy design, in the second embodiment as well, in the same way as in the third embodiment, the selection of the gray code conversion table allows the shortest pulse to be more than twice the pulse time width in the recording pulse train as described above. Can be set to In that case, it is also conceivable that the blocks 102 and 105 relating to the transmission and reception of LVDS in FIG. 1 are omitted, and the gray code is transmitted as a normal binary signal between the signal processing lSI and the laser driver.

  In addition, in the power level setting to the laser driver in the fifth embodiment, the setting based on the address and the DAC value has been described. However, since the power level setting is the same in the first to third embodiments, the above-described setting is performed. Needless to say, the setting method and the control configuration of the current source circuit are also applicable to the first to third embodiments.

<< Embodiment 6 >>
FIG. 14 shows a block diagram relating to an information recording operation of the optical disc apparatus in the sixth embodiment of the present invention. In the figure, blocks having the same functions as those in FIGS. 1 and 12 are given the same reference numerals, and description thereof is omitted.

  The difference between FIG. 14 and FIGS. 1 and 12 is that a conversion table switching circuit 1401 is added. The conversion table generation circuit switches the conversion table used in the encoding circuit 100 and the decoding circuit 107 in accordance with the mark / space information output from the mark / space determination circuit 1201. The conversion table to be used is selected based on, for example, each mark length and the number of multipulses based on the gray code conversion state transition diagram 1204 shown in the fourth embodiment.

  FIG. 15 is a flowchart showing the information recording operation on the optical disc in the present embodiment. When a recording command and recording data are received from the host host (1501), the recording strategy information of the disc (referred to as strategy A) is read from the recording strategy table (1502). Next, the state transition corresponding to the strategy A is selected from the state transition memory for performing the gray code conversion (1503), and each mark length and space in the state transition is stored in the conversion table memory mounted on the signal processing LSI and the laser driver. A conversion table corresponding to the length is set (1504). The state transition registered in the state transition memory and the conversion table on the signal processing LSI and laser driver conversion table memory are configured to be programmable from a microcomputer by firmware or the like for controlling the optical disk device. Next, the NRZ of the recording data is input from the modulation circuit to the mark / space determination circuit (1505), and the determination result is sent to the strategy generation circuit and the conversion table selection circuit (1506). The strategy generation circuit generates recording pulse information from the determination result (1507). In the conversion table selection circuit, a conversion table used for gray code conversion is selected from the determination result and set in the encoding circuit in the signal processing LSI and the decoding circuit of the laser driver (1508). Next, in the encoding circuit, the recording pulse information is converted by the conversion table selected above to generate a gray code (1509) and transmitted to the laser driver (1510). The laser driver converts the received gray code (1511) with the conversion table selected above to generate recording pulse information (1512), outputs a laser pulse train, and executes recording (1513, 1514).

  In the present embodiment, the same effect as in the fourth embodiment can be obtained with a laser driver configuration close to the recording pulse information transmission configuration of the conventional method (1). Thereby, an increase in the scale of the laser driver circuit due to the addition of a current source setting circuit and a switch group can be suppressed. Furthermore, an increase in power consumption can be suppressed as the circuit scale increases, and recording performance deterioration due to heat generated by the laser driver on the pickup can be suppressed.

<< Embodiment 7 >>
FIG. 16 shows a block diagram relating to the information recording operation of the optical disc apparatus in the seventh embodiment of the present invention. In the same figure, blocks having the same functions as those in FIG.

  The difference from FIG. 1 is that changeover switches 1602 and 1605 controlled by a control signal 1603 by a recording strategy generation circuit are provided in the signal processing LSI 1601 and the laser driver 1604. The switch 1602 switches the pulses L0 to L3 and Hfon output from the recording strategy generation circuit 315 shown in FIG. 8 in the second embodiment, and the encoding result pulses Bit0 to Bit2 output from the encoding circuit 100, and switches the LVDS. Output to the transmission circuit 102. At this time, five pulses are output from the switch 1602 corresponding to L0 to L3 and Hfon, but since there are three pulses output from the encoding circuit 100, the switch 1602 outputs the output of the encoding circuit 100. When selected, the two LVDS transmission paths are unused. As for the LVDS transmission path when selecting an encoding circuit, signal leakage between the transmission paths can be reduced by, for example, selecting every other five LVDS transmission paths. The switch 1605 switches the output from the LVDS reception circuit 105 and the output from the decoding circuit 107, and outputs the result to the subsequent switches 305 to 309. The switches 1602 and 1605 are set in conjunction with each other. When the pulses 160 to L3 and Hfon are selected by the switch 1602, the output of the LVDS receiving circuit 105 is selected by the switch 1605. Similarly, when the pulse Bit 0 to Bit 2 are selected by the switch 1602, the output of the decoding circuit 107 is selected by the switch 1605.

  FIG. 17 is a flowchart showing the information recording operation on the optical disc in the present embodiment. In this figure, the same processing numbers as those in FIG. 7 showing the operation flow in the first embodiment are given the same reference numerals.

When a recording command and recording data are received from the upper host (701), the recording strategy information of the disc (this is referred to as strategy A) is read from the recording strategy table (702). Here, it is determined whether the read strategy A is a gray code usable strategy (1701). For the criteria for determining whether the Gray code can be used,
1. Whether or not all pulse time widths for transmitting gray codes by state transition can be set to more than twice the pulse time width in the recording pulse train.
2. Whether the combination of the number of power levels and change timing can be encoded within the number of bits of the encoding circuit.
3. Check if the recording speed is higher than the specified speed.
Judgment is made by If it is determined in the determination 1701 that the gray code can be used, a conversion table corresponding to the strategy A is set in the conversion table mounted on the signal processing LSI and the laser driver (703). The conversion table is set programmable from a microcomputer by firmware or the like for controlling the optical disk apparatus. If it is determined in decision 1701 that the gray code cannot be used, the conversion table is not processed. Next, the NRZ of the recording data is input from the modulation circuit to the mark / space determination circuit (704), the determination result is input to the strategy generation circuit (705), and recording pulse information is generated (706). Here, in the same manner as in decision 1701, it is determined whether strategy A is a gray code usable strategy (1702), and if it is usable, the recording pulse information is converted by the encoding circuit of the signal processing LSI as set above. It is encoded in the table (707) and transmitted to the laser driver (708). When the gray code cannot be used, the recording pulse information is directly transmitted to the laser driver through the LVDS transmission circuit. When the laser driver receives the encoding result (709), it determines whether the recording strategy A being used is a strategy that can use the gray code (1703), and if it can be used, it is converted using the conversion table set above. Then, recording pulse information is generated (710), and a laser pulse train is output to execute recording (711,712). If it is not usable, recording is executed by outputting a laser pulse train using the obtained recording pulse information. Note that the above determination processes 1702 and 1703 have the same result as the determination 1701, and therefore the result of the determination 1701 may be used as it is.

  By the above processing, if the recording strategy is complicated and encoding with a limited number of bits is difficult, the recording pulse information is transmitted directly, the recording speed is increased and transmission of short pulses is difficult, and the phase shift between pulses When the influence of recording strategy deterioration due to the recording is large, it is possible to switch the recording pulse information to be encoded and transmitted in gray code etc., and the best way to design the recording strategy for the first to fifth embodiments An optimized recording strategy can be set according to conditions such as improvement in the degree of freedom and recording speed.

<< Embodiment 8 >>
FIG. 18 is a block diagram showing the information recording operation of the optical disc apparatus according to the eighth embodiment of the present invention. In the same figure, blocks having the same functions as those in FIG.

  The difference from FIG. 12 is that the changeover switches 1803 and 1806 controlled by the control signal 1804 by the recording strategy generation circuit are provided in the signal processing LSI 1801 and the laser driver 1805, and the control signal 1804 is provided in the signal processing LSI 1801. This is the point that a power setting switching circuit 1802 controlled by the above is provided. The change-over switches 1803 and 1806 are switches for switching whether the transmission signal between the signal processing LSI and the laser driver is recording pulse information or gray code, as in the seventh embodiment. The power setting changeover switch 1802 switches the setting of the current source setting circuit 1208 in the laser driver in conjunction with the switching of the transmission signal. When the transmission signal between the signal processing LSI and the laser driver is used as recording pulse information, the current source setting circuit 1209 sets a power level corresponding to each pulse. When the transmission signal between the signal processing LSI and the laser driver is a gray code, the power level for each state of the gray code is set in the current source setting circuit 1209 as shown in the example of FIG. In the example of FIG. 13, the number of power levels when using gray code is 3 bits and 8 values, but the power level when using recording pulse information is, for example, L0 to L3 in the fourth embodiment, 5 values of Hfon. For this reason, if the use of recording pulse information is selected, the power output of the laser driver can be reduced by setting the current output to zero for unused current source circuits and fixing the operation of unused switches. I can do it.

  According to the present embodiment, even when recording pulse information is converted into gray code using state transition and transmitted, recording pulse information transmission and gray code encoding result transmission can be switched and used. The same effects as in the seventh embodiment can be obtained.

  In the laser driver according to the embodiment of the present invention, the current output portion is shown as a configuration for switching the switch. However, for example, the current source circuit is a DAC circuit, and the DAC value is switched using a gray code. However, the present invention is not limited to the embodiment of the present invention.

  In the seventh and eighth embodiments, the switch control is performed from the recording strategy generation circuit. However, it is also conceivable that the control is programmable by a microcomputer or the like with firmware for controlling the optical disk apparatus.

  Also, in the first and seventh embodiments of the present invention, switching of the conversion memory table is controlled by the output of the mark and space determination circuit, but it is programmable by a microcomputer or the like with firmware that controls the optical disk device. Control is also conceivable. Similarly, in the sixth embodiment, the conversion table switching circuit is controlled by the output of the mark and space determination circuit, but it is also conceivable that the conversion table switching circuit may be controlled by a microcomputer or the like with firmware for controlling the optical disk device. Similarly, in the second to fifth and eighth embodiments, the state transition selection by the gray code encoder is controlled by the mark and the output of the space determination circuit, but the microcomputer or the like is used to control the optical disk device. It is also conceivable to control in a programmable manner.

Embodiment 9
FIG. 20 shows a diagram of recording pulse information transmission in the ninth embodiment of the present invention. This figure is a castle type strategy as in FIG. 8, but the recording pulse shape of the 3T mark is different from FIG.

  As described in the second embodiment, when the recording pulse information of L0 to L3 and Hfon is converted to gray code and transmitted, the pulse power value including on / off of the HF output and the gray code correspond one-to-one. Let's consider transmission. This is transmission in which the on / off state of HF is regarded as an edge of pulse power change, and the gray code is changed at the edge point of the recording pulse, that is, the state transition is performed. Thus, in order to make the pulse power value and the gray code have a one-to-one correspondence, it is necessary to output the same gray code in the space portion indicated by 2004 in the figure (in this case, the state where HF is turned on).

  On the other hand, as is clear from the state transition diagram of the gray code shown in FIG. 9, when the state change is performed from a certain state in the gray code to return to the original state, the number of state transitions must be an even number. Become. However, when returning from the space portion described above to the original space portion via a 3T recording pulse, the number of pulse edges (including ON / OFF of HF) is five. Therefore, when the 3T mark is generated, there arises a problem that the state transition of the gray code cannot return to the original state.

  In order to avoid this, a gray code state transition by a dummy edge is generated. The dummy edge corresponds to 2009 in FIG. 20, and no change in pulse power occurs in the recording pulse train 2003 in this portion. However, by changing the gray code state at the dummy edge as shown in 2010 in the figure, the number of gray code state transitions that were odd times with the 3T mark can be made even, and the space portion The gray code state can be restored.

  FIG. 21 is a flowchart showing the information recording operation on the optical disc in the present embodiment. In this figure, the same process numbers as those in FIG. 19 showing the operation flow in the fifth embodiment are given the same figure numbers.

  From the reception of the recording command and recording data from the host host (1901) to the processing of inputting the NRZ of the recording data output from the modulation circuit to the mark / space determination circuit (1904) It is the same. In the fifth embodiment, the gray code state transition is selected from the above mark / space determination result, but in this embodiment, in addition to this, a recording strategy is generated from the above mark / space determination result. (1906) The number of pulse edges of the recording strategy is also added to the state transition selection condition (2101). When the number of pulse edges is an odd number, a state transition with a dummy edge is selected (2102), and when the number of pulse edges is an even number, a state transition without a dummy edge is selected (2103). The subsequent processing is the same as in the fifth embodiment, and the description thereof is omitted here. Thus, by changing the state transition of the gray code to be encoded according to the number of pulse edges, it is possible to realize the state transition that returns to the original state regardless of the recording mark length, as described above.

  In this way, by appropriately changing the state of the gray code at the portion where the power level of the recording pulse does not change, the state change of the gray code at each mark can always be an even number of times, and the number of gray code states can be reduced. It is possible to efficiently allocate the power level of the recording pulse to the gray code while minimizing it.

The timing for generating the dummy edge described above is as follows:
1. Generated after a predetermined time from the previous pulse edge.
2. Generated after a predetermined time from the falling edge (mark end edge) of the recording signal (2000 in FIG. 20).
3. Generated a predetermined time before the rising edge (mark start edge) of the recording signal (2000 in FIG. 20).
4. Generated in synchronization with a predetermined edge of the recording clock synchronized with the recording signal (for example, after a predetermined clock period from the falling edge of the recording signal).
5. It is generated at a predetermined position inside the recording strategy (for example, an intermediate position of the top pulse 2011 in FIG. 20).
Various timings can be considered. In any case, it is sufficiently shifted in time so that the pulse edge of the gray code pulse (Bit 0 to Bit 2 in FIG. 20) can be generated with respect to the edge position of the recording pulse where the gray code state transition occurs. A dummy edge may be generated at the position.

FIG. 3 is a block diagram showing the information recording operation of the optical disc device according to the first embodiment. The figure which shows an example of a recording strategy and its production | generation method. The figure which shows an example of a structure of the block in connection with the information recording operation | movement of the conventional optical disk apparatus. The figure which shows an example of a structure of the block in connection with the information recording operation | movement of the conventional optical disk apparatus. FIG. 3 is a diagram showing a method for transmitting recording strategy information of the optical disc device according to the first embodiment. FIG. 5 is a diagram showing an encoding table of recording pulse information in the first embodiment. 3 is a flowchart showing an information recording operation on an optical disc in the first embodiment. The figure of the recording pulse information transmission in 2nd Embodiment. The figure which shows the state transition of a gray code. FIG. 10 is a diagram showing an encoding table of recording pulse information in the second embodiment. The figure of the recording pulse information transmission in 3rd Embodiment. FIG. 10 is a configuration diagram of a block related to an information recording operation of an optical disc device according to a fifth embodiment. The figure which shows the state transition of the gray code conversion in 4th Embodiment. FIG. 16 is a block diagram related to an information recording operation of an optical disc device according to a sixth embodiment. 10 is a flowchart showing an information recording operation on an optical disc in a sixth embodiment. FIG. 16 is a block diagram related to an information recording operation of an optical disc device according to a seventh embodiment. 15 is a flowchart showing an information recording operation on an optical disc in a seventh embodiment. FIG. 20 is a configuration diagram of a block related to an information recording operation of an optical disc device according to an eighth embodiment. 9 is a flowchart showing an information recording operation on an optical disc in a fifth embodiment. FIG. 10 is a diagram of recording pulse information transmission according to the ninth embodiment. 10 is a flowchart showing an information recording operation on an optical disc in a ninth embodiment.

Explanation of symbols

103, 311, 403 ... signal transmission path, 104, 303, 401, 1206, 1604 ... laser driver, 108, 312, 408, 1205, 1402, 1601 ... signal processing LSI, 200 ... recording signal, 201 ... reference recording clock, 202, 2002 ... recording mark, 203, 2000 ... recording laser pulse train, 205 to 209, 2005 to 2008, 2012 ... pulse signal, 300 ... optical disc, 301 ... spindle, 302 ... laser diode, 305 to 309 ... output selector switch, 318 ... Host host, 801 to 803, 1005 to 1007 ... Code bit signal, 1210 ... Output selector switch group

Claims (55)

In an optical disc apparatus for recording information on a recording medium using a pulse train by laser emission,
A laser pulse train generation circuit for determining a mark length on a recording medium from information to be recorded on the recording medium, a space length;
Based on the laser pulse train output from the laser pulse train generation circuit, a change timing signal generation circuit for outputting a change timing signal based on a plurality of binary pulse trains indicating the change timing of the laser emission amount, and on the basis of the plurality of change timing signals An optical disc device comprising a laser driving circuit for generating a laser driving current for forming a laser pulse train,
An optical disc apparatus characterized in that the number of change timing signals is smaller than the difference number of laser power values. In an optical disc apparatus for recording information on a recording medium using a pulse train by laser emission,
A laser pulse train generation circuit for determining a mark length on a recording medium from information to be recorded on the recording medium, a space length;
Based on the laser pulse train output from the laser pulse train generation circuit, a change timing signal generation circuit for outputting a change timing signal based on a plurality of binary pulse trains indicating a change timing of the laser emission amount and the plurality of change timing signals are predetermined. An encoding circuit that converts and outputs a code signal based on the conversion table of
A decode circuit that converts the code signal into a plurality of laser emission amount change timing signals based on a predetermined conversion table, and a laser drive current that forms a laser pulse train based on the plurality of change timing signals output from the decode circuit An optical disc apparatus comprising: a laser driving circuit that generates a laser beam. In an optical disc apparatus for recording information on a recording medium using a pulse train by laser emission,
A laser pulse train generation circuit for determining a mark length on a recording medium from information to be recorded on the recording medium, a space length;
Based on the laser pulse train output from the laser pulse train generation circuit, a change timing signal generation circuit for outputting a change timing signal based on a plurality of binary pulse trains indicating a change timing of the laser emission amount and the plurality of change timing signals are predetermined. An encoding circuit that converts and outputs a code signal based on the conversion table of
A plurality of change timing signals output from the change timing signal generation circuit and a code signal output from the encoding circuit are switched and input via the signal transmission path and a first switch circuit that outputs the signal to the signal transmission path. A decoding circuit that converts a code signal into a plurality of laser emission amount change timing signals based on a predetermined conversion table, and a plurality of change timing signals and decode circuits that are transmitted from the change timing signal generation circuit via the transmission path A second switch circuit for switching and outputting a plurality of change timing signals to be output; and a laser drive circuit for generating a laser drive current for forming a laser pulse train based on the output of the switch circuit. An optical disk device. The optical disk apparatus according to claim 3, wherein
When the shape of the laser pulse train generated by the laser pulse train generation circuit is a predetermined shape,
Selection of outputting a code signal output from the encoding circuit to the signal transmission path in the first switch circuit;
Encoding process in the encoding circuit;
A decoding process in the decoding circuit and a selection to output a plurality of change timing signals output from the decoding circuit to the laser driving circuit in the second switch circuit;
Carried out
Except for the above cases,
Selection for outputting a plurality of change timing signals output from the change timing signal generation circuit to the signal transmission line in the first switch circuit. Plural change timings output from the change timing signal generation circuit in the second switch circuit. An optical disc apparatus for performing selection to output a signal to a laser driving circuit. The optical disk apparatus according to claim 3, wherein
When the number of power levels of the laser pulse train generated by the laser pulse train generation circuit is a predetermined value or less,
Selection of outputting a code signal output from the encoding circuit to the signal transmission path in the first switch circuit;
Encoding process in the encoding circuit;
A decoding process in the decoding circuit and a selection to output a plurality of change timing signals output from the decoding circuit to the laser driving circuit in the second switch circuit;
Carried out
Except for the above cases,
Selection for outputting a plurality of change timing signals output from the change timing signal generation circuit to the signal transmission line in the first switch circuit. Plural change timings output from the change timing signal generation circuit in the second switch circuit. An optical disc apparatus for performing selection to output a signal to a laser driving circuit. The optical disk apparatus according to claim 3, wherein
When the time interval of the change timing of the laser emission amount in the laser pulse train generated by the laser pulse train generation circuit is a predetermined value or less,
Selection of outputting a code signal output from the encoding circuit to the signal transmission path in the first switch circuit;
Encoding process in the encoding circuit;
A decoding process in the decoding circuit and a selection to output a plurality of change timing signals output from the decoding circuit to the laser driving circuit in the second switch circuit;
Carried out
Except for the above cases,
Selection for outputting a plurality of change timing signals output from the change timing signal generation circuit to the signal transmission line in the first switch circuit. Plural change timings output from the change timing signal generation circuit in the second switch circuit. An optical disc apparatus for performing selection to output a signal to a laser driving circuit. The optical disk apparatus according to claim 3, wherein
When the recording clock period synchronized with the recording data to be recorded on the recording medium is below a predetermined value,
Selection of outputting a code signal output from the encoding circuit to the signal transmission path in the first switch circuit;
Encoding process in the encoding circuit;
A decoding process in the decoding circuit and a selection to output a plurality of change timing signals output from the decoding circuit to the laser driving circuit in the second switch circuit;
Carried out
Except for the above cases,
Selection for outputting a plurality of change timing signals output from the change timing signal generation circuit to the signal transmission line in the first switch circuit. Plural change timings output from the change timing signal generation circuit in the second switch circuit. An optical disc apparatus for performing selection to output a signal to a laser driving circuit. The optical disk apparatus according to claim 3, wherein
When the number of different laser emission amounts in the laser pulse train generated by the laser pulse train generation circuit is equal to or less than the number of combinations represented by the predetermined code, the code signal output from the encoding circuit in the first switch circuit is Select to output to the signal transmission path,
Encoding process in the encoding circuit;
A decoding process in the decoding circuit and a selection to output a plurality of change timing signals output from the decoding circuit to the laser driving circuit in the second switch circuit;
Carried out
Except for the above cases,
Selection for outputting a plurality of change timing signals output from the change timing signal generation circuit to the signal transmission line in the first switch circuit. Plural change timings output from the change timing signal generation circuit in the second switch circuit. An optical disc apparatus for performing selection to output a signal to a laser driving circuit. The optical disc apparatus according to any one of claims 2 to 8,
An optical disc apparatus characterized in that a conversion table used for conversion of a change timing signal and a code signal in the encoding circuit and a conversion table used for conversion of a code signal and a change timing signal in the decoding circuit are the same. The optical disk apparatus according to any one of claims 2 to 9,
Of the conversion table used for conversion of the change timing signal and the code signal in the encoding circuit and the conversion table used for conversion of the code signal and the change timing signal in the decoding circuit,
One or both of them is changed based on the shape of the laser pulse train generated by the laser pulse train generation circuit. The optical disk apparatus according to any one of claims 2 to 9,
A state transition circuit for performing state transition based on the laser pulse train generated by the laser pulse train generation circuit and outputting the state;
Of the conversion table used for conversion of the change timing signal and the code signal in the encoding circuit and the conversion table used for conversion of the code signal and the change timing signal in the decoding circuit,
One or both of them is changed based on the state output of the state transition circuit. The optical disc apparatus according to claim 11, wherein
A state transition memory for storing the state transition of the state transition circuit;
An optical disc apparatus characterized in that a state transition circuit selects a state transition from the state transition memory and performs state transition. In an optical disc apparatus for recording information on a recording medium using a pulse train by laser emission,
A laser pulse train generation circuit for determining a mark length on a recording medium from information to be recorded on the recording medium, a space length;
Based on the laser pulse train output from the laser pulse train generation circuit, information is recorded on the recording medium and a change timing signal generation circuit for outputting a change timing signal based on a plurality of binary pulse trains indicating the change timing of the laser emission amount. A state transition circuit for performing state transition based on the laser pulse train used in the process and outputting the state, and assigning the states of the plurality of change timing signals to a predetermined code based on the state output of the state transition circuit, and outputting them as code signals A decoding circuit that changes the code signal to a plurality of laser emission amount change timing signals based on a status output of the encoding circuit and the state transition circuit, and a plurality of change timing signals output from the decoding circuit A laser that generates laser drive current, forming a laser pulse train Optical disk apparatus characterized by comprising a dynamic circuit. The optical disk apparatus according to claim 13, wherein
An optical disc apparatus characterized by changing a state transition in a state transition circuit based on a shape of a laser pulse train output from a laser pulse train generation circuit. The optical disk apparatus according to claim 13 or 14,
A mark and space length discriminating circuit for discriminating the mark length and space length on the recording medium from the information recorded on the recording medium,
An optical disc apparatus characterized by changing a state transition in a state transition circuit based on an output of a mark and space length discrimination circuit. The optical disk apparatus according to claim 13, wherein
A state transition memory for storing the state transition of the state transition circuit;
An optical disc apparatus characterized in that a state transition circuit selects a state transition from the state transition memory and performs state transition. The optical disk device according to any one of claims 2 to 16,
A microcomputer for controlling the operation of the optical disk device and a memory for storing the operation program are provided.
Among the conversion table used for conversion of the change timing signal and the code signal in the encoding circuit, the conversion table used for conversion of the code signal and the change timing signal in the decoding circuit, and the state transition operation of the state transition circuit, or the state transition memory ,
Any one or more or all of them can be changed programmably from the microcomputer. The optical disk apparatus according to any one of claims 2 to 17,
The code signal is a multi-value signal composed of 2 or more bits,
An optical disc apparatus characterized in that the continuous change of the multilevel signal is 1 bit. The optical disk apparatus according to claim 18, wherein
An optical disc apparatus characterized in that when a multilevel signal changes at a certain arbitrary bit, the next change of the multilevel signal is realized by a bit different from the arbitrary bit. The optical disk device according to claim 18 or 19,
An optical disc apparatus characterized in that a time interval of signal change of the same bit in the multilevel signal is set to one period or more of a recording clock synchronized with recording data to be recorded on the recording medium. In an information recording method for recording information on a recording medium using a pulse train by laser emission,
Determine the mark length and space length on the recording medium from the information recorded on the recording medium, determine the shape of the laser pulse train from the output of the mark, space length determination circuit and mark, space length determination circuit,
Based on the laser pulse train, a change timing signal is generated by a plurality of binary pulse trains indicating the change timing of the laser emission amount,
Based on the plurality of change timing signals, a laser driving current forming a laser pulse train is generated to emit a laser,
An information recording method for recording information,
An information recording method according to claim 1, wherein the number of change timing signals is less than the number of differences in laser power values. In an information recording method for recording information on a recording medium using a pulse train by laser emission,
Determine the mark length and space length on the recording medium from the information recorded on the recording medium,
Determine the shape of the laser pulse train from the discrimination result,
Based on the laser pulse train, a change timing signal is generated by a plurality of binary pulse trains indicating the change timing of the laser emission amount,
Generating a code signal in which the plurality of change timing signals are assigned to a code based on a predetermined conversion table;
A plurality of laser emission amount change timing signals are generated from the code signal based on a predetermined conversion table,
Based on a plurality of change timing signals generated from the code signal, a laser drive current forming a laser pulse train is generated and generated, and a laser is emitted.
An information recording method comprising performing information recording. In an information recording method for recording information on a recording medium using a pulse train by laser emission,
Determine the mark length and space length on the recording medium from the information recorded on the recording medium,
Determine the shape of the laser pulse train from the discrimination result,
Based on the laser pulse train, a change timing signal is generated by a plurality of binary pulse trains indicating the change timing of the laser emission amount,
Based on the shape of the laser pulse train,
Based on the change timing signals by the plurality of binary pulse trains, a first laser emission control method for generating and generating a laser drive current for forming a laser pulse train and emitting the laser, and the change timings by the plurality of binary pulse trains Generate a code signal that assigns a signal to a code based on a predetermined conversion table,
A plurality of laser emission amount change timing signals are generated from the code signal based on a predetermined conversion table,
Based on a plurality of change timing signals generated from the code signal, information recording is performed by switching between a second laser emission control method for generating and generating a laser driving current for forming a laser pulse train and emitting a laser. A characteristic information recording method. The information recording method according to claim 22,
Based on the number of power levels of the laser pulse train determined from the information recorded on the recording medium,
An information recording method, wherein information recording is performed by switching between the first laser emission control method and the second laser emission control method. The information recording method according to claim 22,
When the time interval of the change timing of the laser emission amount in the laser pulse train determined from the information recorded on the recording medium is a predetermined value or more, the first laser emission control method is selected,
An information recording method characterized by selecting the second laser emission control method and performing information recording in cases other than the above. The information recording method according to claim 22,
Selecting the first laser emission control method when the number of different laser emission amounts in the laser pulse train generated by the laser pulse train generation circuit is equal to or greater than the number of combinations represented by the predetermined code;
An information recording method characterized by selecting the second laser emission control method and performing information recording in cases other than the above. The information recording method according to any one of claims 20 to 25,
The conversion table used when generating the code signal from the plurality of change timing signals is the same as the conversion table used when generating the plurality of laser emission amount change timing signals from the code signal. Recording method. The information recording method according to any one of claims 20 to 26,
Among the conversion table used when generating a code signal from the plurality of change timing signals and the conversion table used when generating a plurality of laser emission amount change timing signals from the code signal,
An information recording method comprising changing either one or both based on the shape of a laser pulse train determined from information recorded on a recording medium. The information recording method according to any one of claims 20 to 27,
Determine the state transition based on the laser pulse train determined from the information to be recorded on the recording medium,
Among the conversion table used when generating a code signal from the plurality of change timing signals and the conversion table used when generating a plurality of laser emission amount change timing signals from the code signal,
Either or both of them are changed based on the state transition. The information recording method according to any one of claims 20 to 27,
A plurality of state transitions are stored in advance in the state transition storage means for storing state transitions,
Among the conversion table used when generating a code signal from the plurality of change timing signals and the conversion table used when generating a plurality of laser emission amount change timing signals from the code signal,
Either or both are changed based on the state transition memorize | stored in the said state transition memory | storage means, The information recording method characterized by the above-mentioned. In an information recording method for recording information on a recording medium using a pulse train by laser emission,
Determine the mark length and space length on the recording medium from the information recorded on the recording medium,
Determine the shape of the laser pulse train from the discrimination result,
Based on the laser pulse train, a change timing signal is generated by a plurality of binary pulse trains indicating the change timing of the laser emission amount,
Determine the state transition based on the laser pulse train,
Based on the state transition determined based on the laser pulse train, a code signal in which the plurality of change timing signals are assigned to the code is generated, and on the basis of the state transition, a plurality of laser emission amount change timing signals are generated. And
Based on a plurality of change timing signals generated from the code signal, a laser drive current forming a laser pulse train is generated and generated, and a laser is emitted.
An information recording method comprising performing information recording. The information recording method according to claim 30, wherein
An information recording method, wherein state transition is changed based on a shape of a laser pulse train determined from information recorded on a recording medium. The information recording method according to claim 30 or 31,
Determine the mark length and space length on the recording medium from the information recorded on the recording medium,
An information recording method, wherein state transition is changed based on a mark / space length discrimination result. The information recording method according to claim 30, wherein
A plurality of state transitions are stored in advance in the state transition storage means for storing state transitions,
An information recording method comprising performing state transition by selecting a state transition from the state transition memory. The information recording method according to any one of claims 20 to 33,
A conversion table used when generating a code signal from the plurality of change timing signals, and a conversion table used when generating a plurality of laser emission amount change timing signals from the code signal;
Of the state transition operation or the state transition stored in the state transition storage means,
Any one or more or all of them are programmably changed from a control means such as a microcomputer. The information recording method according to any one of claims 20 to 34,
The code signal is a multi-value signal composed of 2 or more bits,
An information recording method according to claim 1, wherein the continuous change of the multilevel signal is 1 bit. 36. The information recording method according to claim 35, wherein
An information recording method characterized in that when a multilevel signal changes at a certain arbitrary bit, the next change of the multilevel signal is realized by a bit different from the arbitrary bit. The information recording method according to claim 35 or 36,
The information recording method according to claim 1, wherein a time interval of signal change of the same bit in the multilevel signal is set to one period or more of a recording clock synchronized with recording data to be recorded on the recording medium. The mark according to claim 1, a space length determination circuit,
A laser pulse train generation circuit;
A change timing signal generation circuit;
A signal processing LSI comprising: The mark according to claim 2, a space length discrimination circuit,
A laser pulse train generation circuit;
A change timing signal generation circuit;
An encoding circuit;
A signal processing LSI comprising: The mark and space length determination circuit according to any one of claims 3 to 10,
A laser pulse train generation circuit;
A change timing signal generation circuit;
An encoding circuit;
A first switch circuit;
A signal processing LSI comprising: The mark or space length determination circuit according to any one of claims 11 or 13 to 15,
A laser pulse train generation circuit;
A change timing signal generation circuit;
An encoding circuit;
A state transition circuit;
A signal processing LSI comprising: The mark or space length determination circuit according to claim 12 or 16,
A laser pulse train generation circuit;
A change timing signal generation circuit;
An encoding circuit;
A state transition circuit;
State transition memory;
A signal processing LSI comprising: The signal processing LSI according to any one of claims 38 to 42,
Among the conversion table used for conversion of the change timing signal and code signal in the encoding circuit and the state transition operation of the state transition circuit, or the state transition memory,
Any one or more or all of the signal processing LSIs can be changed in a programmable manner from inside or outside of the signal processing LSI. A laser driver comprising the laser drive circuit according to claim 1. A decoding circuit according to claim 2;
A laser drive circuit;
Laser driver equipped with. A decoding circuit according to any one of claims 3 to 10,
A second switch circuit;
A laser drive circuit;
Laser driver equipped with. A decoding circuit according to any one of claims 11 to 16,
A laser drive circuit;
Laser driver equipped with. 48. A laser driver according to any one of claims 44 to 47, wherein a conversion table used for conversion between a code signal and a change timing signal in the decode circuit can be changed programmably from an internal or external microcomputer of the laser driver. A laser driver characterized by 21. The optical disc apparatus according to claim 2, wherein:
The state of the change timing signal before and after a certain time is the same,
An optical disc apparatus characterized in that code signals before and after the time are different. 21. The optical disc apparatus according to claim 2, wherein:
The laser power or laser waveform before and after a certain time is the same,
An optical disc apparatus characterized in that code signals before and after the time are different. The information recording method according to any one of claims 21 to 37,
The state of the change timing signal before and after a certain time is the same,
An information recording method characterized in that code signals before and after the time are different. The information recording method according to any one of claims 21 to 37,
The laser power or laser waveform before and after a certain time is the same,
An information recording method characterized in that code signals before and after the time are different. 51. A signal processing LSI comprising an encoding circuit for generating the code signal according to claim 49 or 50. 54. The signal processing LSI according to claim 53,
Among the conversion table used for conversion of the change timing signal and code signal in the encoding circuit and the state transition operation of the state transition circuit, or the state transition memory,
Any one or more or all of the signal processing LSIs can be changed in a programmable manner from inside or outside of the signal processing LSI.

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