JP4604924B2 - Optical disc recording method, optical disc apparatus, and optical disc - Google Patents

Description

The present invention relates to an optical disc that records information by irradiation with an energy beam, and more particularly to an optical disc recording method that exhibits excellent effects on various high-density write-once optical discs having different compositions and recording mechanisms, and uses the recording method. The present invention relates to an optical disc apparatus.

In recent years, DVD-RAMs having a recording capacity of 4.7 GB per side on a 120 mm diameter disk using a phase change material have been put into practical use. In a DVD-RAM, a recording film has a first state (mark) and a second state (space), and information is marked by making the first state and the second state a predetermined repeating pattern. Edge recording. How to change the irradiation power level with time when recording information by irradiating the recording film with an energy beam,
Generally called a recording strategy.

The recording strategy of the DVD-RAM is as shown in FIG. 2, and a first power level (recording power level Pw) for setting the first state and a second power level for setting the second state. Energy beam (bias level Pb2) and a third power level (bias level Pb1) lower than the first and second power levels, and the energy beam is changed in a pulse shape. In particular, when forming a recording mark that is in the first state, the first power level and the third power level are alternately multipulsed according to the length of the recording mark for the purpose of preventing distortion of the mark shape. And irradiate.

By the way, if the interval between the positions where two adjacent recording pulses are irradiated is small with respect to the light spot diameter of the energy beam on the recording film, the light distribution overlaps, resulting in mark shape distortion and mark edge shift. It becomes easy. In addition, when the mark or space is short, a mark edge shift occurs in the reproduction signal waveform due to the fact that the reproduction light spot cannot be sufficiently resolved.

In order to solve such a problem of mark edge shift, the above-described multi-pulse recording strategy is used, and in particular, the first power level pulse light is irradiated to the start end portion and end end portion of the mark with a certain width, and the mark A correction technique has been disclosed and put into practice in which the positions of the start and end portions of the recording are changed as needed according to the mark length to be recorded and the space length before and after the recording. (For example, Patent Document 1)
The manner of occurrence of the mark edge shift described above largely depends on the design of the recording film, and a recording strategy suitable for a specific recording film is not necessarily suitable for other recording films. Therefore, in order to support various recording films, the above-described multi-pulse recording strategy is used, and the mark length and the previous space length are recorded with the rising timing recorded while fixing the falling timing of the leading pulse irradiated to the starting end portion of the mark. In the first case, which is changed as needed,
The second case where the width of the leading pulse is fixed and the rising and falling timings are recorded is changed according to the disc according to the disc length and the previous space length. Similarly, with respect to the last pulse irradiated to the end portion of the mark, similarly, the first case where the falling timing is changed according to the recording mark length and the rear space length while fixing the rising timing, and the width of the final pulse is fixed. Thus, a correction technique for switching between the second case where the rising and falling timing is changed at any time according to the recording mark length and the rear space length is disclosed and put into practical use. (For example, Patent Document 2)

Japanese Patent Laid-Open No. 7-129959 (first page, FIG. 2) JP 2000-149265 A (page 8)

In recent years, optical disks have been increasing in density with the increase in data capacity to be handled, and the above-mentioned DVD-RAM is used for a CD having a capacity of about 700 MB (megabytes).
In general, DVDs with a capacity of about 4.7 GB (Gigabytes) are widely used.
In addition, a next-generation optical disc with a capacity of 20 GB or more capable of recording high-definition video for 2 hours has been developed.
Here, a short wavelength semiconductor laser with a wavelength of 405 nm band (blue violet) is used as a light source, and the numerical aperture of the objective lens is improved to 0.85. The modulation code is also D
The EFM-plus used in VD has been changed to 1-7PP modulation.
In terms of a limited code, DVD is RLL (2, 10), while RLL (
1, 7). By changing the modulation code, the mark length and the space length are 3 Tw to 11 Tw in the DVD when the data detection window width is Tw, whereas the mark length and the space length are 2 in the current code.
It changes from Tw to 8Tw.

FIG. 5 shows various characteristics in each code when the transfer time T per user is 24 ns. Since the shortest mark length and the shortest space length are shortened while the detection window width is widened, there is a problem that each power level and recording strategy for recording the optimum mark are different from those of the DVD-RAM. Further, since the shortest mark length and the shortest space length with respect to the reproduction light spot are shortened, there is a problem that the resolution is lowered and the mark edge shift becomes more remarkable.

The shortest mark length in the linear direction is about 0.42 μm for DVD-RAM, while it is about 0.15 μm for the next-generation optical disk, and the adjacent mark and space interval are physically closer. It has become. For this reason, there is a problem that heat interference is likely to occur due to the energy injected when the mark is recorded. In particular, when a recording medium capable of high-speed recording comes out in the future, it is desirable to record the recording medium with a low-speed recording device for backward compatibility.
Such a recording medium capable of high-speed recording has a characteristic of easily storing heat in order to improve recording sensitivity, and the above-described problem of thermal interference is expected to become more serious. For this reason, there is a problem that the mark edge shift at the time of recording becomes more remarkable.

In the next generation optical disc, it is expected that the accuracy higher than the above-described conventional technology is required for the correction of the mark edge shift.

In the next-generation optical disc, it is conceivable to use not only a phase change film similar to DVD-RAM but also an organic dye film similar to DVD-R and other materials as a recording medium. The mark formation mechanism itself may differ if the recording film material is different, but instead of using a different recording waveform for each medium as the recording strategy, simply change the parameter value without changing the basic waveform. It is desirable to be able to handle each recording medium. Further, it is desirable that the above-mentioned medium capable of high-speed recording can be handled by changing the numerical values of the parameters without changing the basic waveform between high-speed recording and low-speed recording, and in particular, recording on the disk at CAV (constant angular velocity). It is essential when performing.

In view of the above, an object of the present invention is to provide a mark of a modulation code having a shortest mark length and a shortest space length with respect to a detection window width, various recording media having different recording film materials or recording mechanisms, and a medium capable of high-speed recording appearing in the future. On the other hand, accurate recording is possible only by changing the parameter values without changing the basic waveform configuration, especially mark edge shift due to thermal interference during recording and mark edge shift due to resolution during reproduction. An object of the present invention is to provide an optical disc recording method and an optical disc apparatus which can be compensated. Another object of the present invention is to provide an optical disc that facilitates the operation of the optical disc recording method and optical disc apparatus.

The above object can be achieved, for example, by the invention described in the claims.

According to the optical disc recording method and the optical disc apparatus of the present invention, the modulation mark mark having the shortest mark length and the shortest space length with respect to the detection window width is recorded on various recording media having different recording film materials or recording mechanisms, and high-speed recording appearing in the future. Accurate recording can be performed on a possible medium only by changing parameter values without changing the basic waveform configuration. In particular, it is possible to compensate for a mark edge shift due to thermal interference during recording and a mark edge shift due to resolution during reproduction. Further, according to the optical disc of the present invention, the operation of the optical disc recording method and the optical disc apparatus can be facilitated.

  Hereinafter, an optical disk recording method according to a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a recording strategy in the optical disk recording method of the present invention. This embodiment shows a case where information is converted into a modulation code into RLL (1, 7) and recording is performed. When the time width (detection window width) of the reference clock in recording and reproduction is Tw, the shortest is shown. The length of the mark or the shortest space is 2 Tw (a time twice as long as the time Tw), and the length of the longest mark or the longest space is usually 8 Tw.

When an NRZI signal representing information to be recorded on the optical disc in time series is given, the NRZI signal is converted into a time series change of the energy level of the energy beam, that is, a light emission pulse waveform by an appropriate signal processing circuit. .

Here, it is assumed that a rewritable phase change material having good overwrite characteristics is used as the material of the recording film, and the power levels are the recording level Pw, the first bias level Pb1, and the second bias level Pb2. Three levels were set. By irradiating the energy beam at the recording level Pw, the recording film is brought into the first state (mark in this embodiment),
By irradiating the energy beam of the second bias level Pb2, the recording film is in the second state (
In this embodiment, it is possible to reversibly move to a space). The first bias level Pb1 is equal to or lower than the second bias level Pb2.

When a mark (region in the first state) is formed on the recording film, if the mark length is 3 Tw or more (that is, the length of the NRZI signal is 3 Tw or more), the first time during the irradiation period of the recording level Pw.
The energy beam is multipulsed by mixing the periods of the bias level Pb1. Of the multi-pulse energy beam, the first light pulse is called the first pulse,
The last light pulse is referred to as the last pulse. Between the first and last pulse, N
An optical pulse that repeats the recording level Pw and the first bias level Pb1 is repeated according to the length of the RZI signal, and the number of repetitions is the length of the NRZI signal n (here, n> 4).
), It is (n-3). The entire repetitive pulse sandwiched between the first pulse and the last pulse is referred to as a comb pulse.

In summary, the total number of light pulses generated when forming a mark corresponding to NRZI having a length of nTw is (n-1). In particular, when a mark corresponding to NRZI having a length of 4 Tw or more is formed, the recording pulse is composed of a leading pulse, a comb pulse, and a final pulse. 3
When a mark corresponding to NRZI having a length of Tw is formed, a recording pulse is composed of a first pulse and a last pulse. When a mark corresponding to NRZI having a length of 2 Tw is formed, the recording pulse becomes a single pulse.

In addition, the energy beam is held at the first bias level Pb1 for a predetermined period following the last pulse at 3 Tw or more and subsequently to the recording pulse at 2 Tw.

By the way, for an optical disc having a recording film made of an organic dye material other than the phase change material, the first recording film is used even if the energy beam is irradiated at the second bias level Pb2.
It is not possible to shift from the state to the second state. Therefore, a recording strategy in which only two power levels of the recording level Pw and the first bias level Pb1 are set may be used.

However, it may be possible to improve the recording characteristics by using a bias level that cannot be recorded. For example, in the case of recording at high speed, especially when there is an output limit of the energy beam, it may not be possible to sufficiently increase the temperature of the recording film only by irradiation with the pulse of the recording level Pw. In order to help the rise, recording can be easily performed by applying preheat at a bias level before recording.
Accordingly, the write-once type optical disc that performs irreversible state change also has a 3 as shown in FIG.
A recording strategy having two power levels can be employed.

Next, definitions of the time (position) and irradiation time (width) of the first pulse and the last pulse in this embodiment will be described. The leading pulse rise time is a time preceding the displacement time dTtop with reference to a time 1 Tw after the rise time of NRZI. In addition,
It assumes that it has a negative value when it rises after the displacement time dTtop with respect to the reference time. Further, the irradiation time Ttop of the leading pulse is a time from the rising time to the falling time of the leading pulse. On the other hand, the rising time of the last pulse is a time that precedes the displacement time dTlp with reference to a time that precedes the falling time of NRZI by 1 Tw. It should be noted that a negative value is assumed when rising after a displacement time dTtop with respect to the reference time. The last pulse irradiation time Tlp is the time from the rising time to the falling time of the final pulse.

In the present embodiment, the 2Tw recording pulse conforms to the definition of the head pulse.

For the comb-shaped pulse, the rising edge of each pulse coincides with the reference clock position, and falls at the time when the time Tmp has elapsed from the rising edge of each pulse.

In addition, regarding the irradiation time of the first bias level after the last pulse described above, NRZI
A time that precedes the displacement time dTe on the basis of the falling time of. It should be noted that a negative value is assumed when rising after a displacement time dTe with respect to the reference time.

In this embodiment, each value of dTtop, Ttop, dTlp, Tlp, Tmp, and dTe is defined as the sum of a linear term and a nonlinear term with respect to the reference clock Tw. For example, dTtop is defined by the following equation.

dTtop = a · Tw / n + b · t
n is a predetermined integer, and Tw / n represents pulse resolution. t is a predetermined time independent of Tw. Moreover, a and b are coefficients of each term, and are integers here.

However, the present invention is not limited to this, and for example, it may be defined only by a linear term with respect to the reference clock Tw, or conversely, it may be defined only by a nonlinear term. In addition, among the parameters, for example, a parameter defined by the sum of a linear term and a nonlinear term and a parameter having only a linear term may be mixed.

By the way, dTtop, Ttop, dTlp define the timing of the recording pulse.
, Tlp, Tmp, and dTe are not necessarily constant values.

In order to compensate for the thermal interference between adjacent marks at the time of recording as described above and the mark edge shift due to insufficient resolution at the time of reproduction, for example, in the above-mentioned DVD-RAM, the definition of pulse timing is not necessarily the same as in this embodiment. However, the parameters defining the rise time of the first pulse and the fall time of the last pulse are sometimes adaptively changed according to the combination of NRZI signals. In particular, the leading pulse may be translated in the time axis direction without changing the irradiation time of the leading pulse, or the rising time may be changed by fixing the falling time. Similarly, the final pulse may be translated without changing the irradiation time, or the rising time may be fixed and the falling may be changed.

However, as described above, particularly in the case where the shortest mark length and the shortest space length are 0.2 μm or less as in the next-generation optical disk assumed in the present invention, the heat between adjacent marks during recording is used. Interference is further increased, and it is difficult to always perform stable recording. The write-once recording film is particularly susceptible to thermal interference, and the front edge shift of the mark due to the difference in front space length is significant.

Also during reproduction, the shortest mark length and the shortest space length are 2 Tw as in the next generation optical disc assumed in the present invention, so that the reproduction of the reproduction signal by the mark edge shift is reduced by reducing the resolution of the reproduction light spot. The performance deterioration becomes remarkable, and there are cases where sufficient correction cannot be performed by the conventional method.

Therefore, in this embodiment, in order to correct a particularly significant front edge shift, the reference table for dTtop and the reference table for Ttop are defined independently as shown in FIG. As a result, the position and width of the leading pulse can be freely defined for the combination of the recording mark length and the previous space length. Precise edge shift correction is possible even for next-generation optical discs with greater interference, thereby improving recording / reproduction performance.

In particular, in this embodiment, the coefficient of the linear term with respect to Tw of each parameter (the above dTto
In the example of p, a reference table for coefficient a) is defined. Since the coefficient is an integer, the amount of information to be recorded can be suppressed, and there is an advantage that it is easy to cope with changes in Tw according to a plurality of recording speeds, such as when recording at CAV (constant angular velocity). .

Alternatively, a reference value for each parameter may be defined in advance, and a displacement amount may be defined for each reference table value. For example, in the above definition of dTtop, the reference value is a0 (integer), the displacement is Δa (integer),
dTtop = (a0 + Δa) Tw / n + b · t
Then, a reference table may be defined for Δa.

For the trailing edge shift, the reference table of dTlp as shown in FIG.
Alternatively, the Tlp lookup table is defined. In addition, the reference table of the dTlp and the Tl
The p reference table is configured to be switchable according to, for example, the difference in the recording film material of the optical disc. A write-once recording film such as an organic dye has a characteristic that it is not easily affected by the difference in the rear space length, and therefore, it is not always necessary to precisely control and correct the rear edge. However, by adopting a configuration in which the rear edge correction is performed in the same manner as in the prior art, it is possible to sufficiently correct the rear edge shift for the phase change recording medium as assumed in the present embodiment.

In addition, it is good also as a structure which respectively defines the reference table regarding said dTlp and said Tlp independently like a head pulse. In this case, instead of increasing the recording strategy variable,
It is possible to freely define the position and width of the final pulse waveform.

In the present embodiment, as shown in FIG. 6, the front space length is set to 2 Tw, 3 for the first pulse.
The 4x3 reference table is classified into four types of Tw, 4Tw, and 5Tw or more, and the recording mark length is classified into 3 types of 2Tw, 3Tw, and 4Tw or more. As for the last pulse, as shown in FIG. 7, a 4 × 2 reference table in which the rear space length is classified into four types of 2Tw, 3Tw, 4Tw, 5Tw or more, and the recording mark is classified into two types of 3Tw, 4Tw or more. did. However, the present invention is not limited to this, and the size of the reference table may be arbitrarily defined in consideration of the dependency on the space length and the recording mark length and the correction effect.

In this embodiment, the timing of each pulse is defined by the rise time and the irradiation time. However, the present invention does not depend on the definition method, and may be defined by the rise time and the fall time, or the fall time. And may be defined by the irradiation time and the central time of the irradiation time.

According to the present invention, it is possible to perform precise mark edge compensation by providing the reference table shown in the present embodiment. Therefore, the basic waveform can be obtained even for various optical disks having different recording films or recording mechanisms. This can be dealt with by changing only the power level and the timing parameter of each pulse including the reference table.

  Next, an optical disk recording method according to the second embodiment of the present invention will be described.

In this embodiment, the time (position) and irradiation time (width) of a 2 Tw recording pulse are defined independently of 3 Tw or more. That is, the rising position of the pulse is dTtop2,
The irradiation time is Ttop2. With respect to dTtop2 and Ttop2, each has a configuration in which a reference table as shown in FIG. 8 is defined independently according to the combination of the front space length and the rear space length. Note that the dTtop and Ttop reference tables are defined with a recording mark length of 3 Tw or more.

Thus, by defining the 2Tw recording pulse by the combination of the front space and the rear space, it is possible to compensate for the space length dependence after the rear edge shift of the 2Tw mark, which could not be controlled in the first embodiment. Other configurations are the same as those in the first embodiment, and the description of the configurations and functions is omitted here.

  An optical disk recording method according to the third embodiment of the present invention will be described.

In this embodiment, as shown in FIG. 3, each parameter is defined by regarding a 2 Tw recording pulse as an overlap of the first pulse and the last pulse. That is, the rise time is defined by the time (position) dTtop of the above-described first pulse, and the fall time is defined by the irradiation time of the last pulse (
Width) Defined by Tlp.

Further, the irradiation time (width) Ttop of the first pulse and the time (position) dTlp of the last pulse are values unique to each recording disk. However, it is defined so that the leading pulse does not exceed the trailing edge, the trailing pulse does not exceed the leading edge, and the leading and trailing pulses are not separated into two pulses.

Alternatively, the irradiation time of the first pulse is always set to the same set value as the irradiation time of the last pulse, and the rising time of the final pulse is always set to the same setting value as the rising time of the first pulse. That is, the head pulse and the last pulse are made coincident, the rising time is changed according to the previous space length, and the falling time is changed according to the rear space length.

Further, regarding the reference table of dTlp and Tlp that define the final pulse, the recording mark lengths were classified into three types including 2Tw marks as shown in FIG. Other configurations are the same as those in the first embodiment, and the description of the configurations and functions is omitted here.

Thus, by defining the 2Tw recording pulse as the overlap between the first pulse and the last pulse, the number of reference tables does not increase as in the second embodiment, and the rear edge shift of the 2Tw mark depends on the space length. Can be compensated. And 2Tw is also 3Tw
There is an effect that it can be handled uniformly as described above.

Next, an optical disk device and an optical disk according to a fourth embodiment of the present invention will be described with reference to the drawings.

FIG. 4 is a block diagram of an optical disc apparatus according to the present invention. Removable optical disk 10
0 is held by a chucking mechanism 112 provided in the spindle motor 110. By driving the spindle motor 110, the optical disc 100 rotates, and the relative position between the energy beam irradiated from the optical pickup 117 and the optical disc 100 is moved. Further, the optical pickup 117 can move linearly in the substantially radial direction of the optical disc 100 along the guide rail 115 by driving the feed motor 116.

The optical pickup 117 is provided with a semiconductor laser 131 which is an energy beam generator. The energy beam emitted from the semiconductor laser 131 is collimated lens 1.
32 and the beam splitter 133, and is collected by the objective lens 136. The objective lens 136 is held by the objective lens actuator 121 and can be displaced and positioned in the direction perpendicular to the recording surface of the optical disc 100 (focus direction) and in the disc radial direction (tracking direction). The light can be condensed at a predetermined position on the optical disc 100.

A part of the energy beam condensed on the recording surface of the optical disc 100 is reflected and transmitted again through the objective lens 136, reflected by the beam splitter 133, condensed by the detection lens 134, and light emitted by the photodetector 135. The intensity is detected. In the photodetector, the light receiving area is divided into a plurality of parts, and the light intensity detected in each light receiving area is amplified and calculated by the amplifier 152 and the light spot collected by the objective lens 136 and the optical disc 100. Information (servo information) and an information reproduction signal are detected. The servo signal is sent to the servo controller 151, and the reproduction signal is sent to the decoder 153.

When the optical disc 100 is attached to the optical disc apparatus and the chucking mechanism 112 fixes the optical disc 100, the detector 140 is activated and the signal is sent to the system controller 150.
Send to. In response to this, the system controller 150 controls the spindle motor 110 to rotate the optical disc 100 to a predetermined rotational speed. Further, the system controller 150 controls the feed motor 118 to position the optical pickup 117 at a predetermined position. In addition, the system controller 150 causes the semiconductor laser 131 to emit light and controls the feed motor 116 via the servo controller 151 to drive the objective lens actuator 121 so that the focal spot formed by the objective lens 136 is a predetermined spot on the optical disc 100. Position to position. Next, the servo controller 151 sends a signal to the system controller 150 indicating that the focal spot is formed on the recording surface on the optical disc 100. The system controller 150 operates the decoder 153 to decode the reproduction signal. If the reproduced track is not an information track in the control zone, the system controller 1
Reference numeral 50 indicates that the focal spot is positioned on the information track in the control zone via the servo controller. As a result of the above operation, the system controller 150 reproduces the information track of the control zone of the optical disc 100 and reads the disc information related to recording.

Here, the optical disc 100 is an optical disc according to the present invention. In the information track of the control zone, as recording disk information, each parameter of the recording strategy as shown in FIG. 1, the reference table shown in the first to third embodiments, and the reference table in some cases are stored. A flag indicating the type (whether the table value is a coefficient or a difference) is recorded in advance. As a result, the operation of the optical disk of this embodiment can be facilitated.

The system controller 150 provides information regarding these recordings, that is, the recording power level,
The time relationship of each recording pulse, each reference table, and flag information are read and written to the parameter table of the signal processing circuit 154, the parameter table of the delay circuit 155, and the current sink amount parameter of the current sink 156. Here, in particular, the delay circuit 155 or the combination of the delay circuit 155 and the signal processing circuit 154 functions as a storage unit for each reference table of the present invention.

The system controller 150 reads the recording strategy parameters of the optical disc 100 and writes them into the parameter table of the signal processing circuit 154, the parameter table of the delay circuit 155, and the current sink amount parameter of the current sink 156. It is only necessary to be in a recordable state, and these processes may be omitted in a recording prohibited state.

When an instruction for reproducing information is sent from the host controller via the input connector 159, the system controller 150 gives an instruction to the servo controller 151 to position the focal spot at an appropriate position on the optical disc 100, and the photodetector. After decoding the reproduction signal obtained at 135, the reproduction information is sent to the host controller through the output connector 158.

When an information recording instruction is sent from the host controller via the input connector 159, the system controller 150 gives an instruction to the servo controller 151 to position the focal spot at an appropriate position on the optical disc 100. Information to be recorded is converted into an NRZI signal by the signal processing circuit 161 and further converted into a plurality of appropriate pulse trains by the signal processing circuit 154. Each of these pulse trains is given a predetermined delay through the delay circuit 155 and is transmitted to the current sink 156.

A constant current source 157 is connected to the semiconductor laser 131, and a plurality of current sinks 156 are connected to the constant current source 157, and the semiconductor laser 131 and the plurality of current sinks 15 are connected.
6 is configured such that the sum of the current consumed at 6 is always constant. Whether the current sink 156 operates and sucks current depends on the signal generated in the signal processing circuit 154 and passed through the delay circuit 155. When the current sink 156 operates, a part of the current supplied from the constant current source 157 is absorbed by the current sink 156, and as a result, the semiconductor laser 13
The amount of current supplied to 1 decreases. This changes the power level of the energy beam emitted by the semiconductor laser. The signal processing circuit 154 and the delay circuit 155 implement the recording strategy of the present invention shown in FIG. 1 by operating a plurality of current sinks 156 at appropriate timing. In other words, the optical disc apparatus of the present embodiment realizes the optical disc recording method shown in the first to third embodiments, and is compatible with the next generation optical disc having a larger interference, in particular, the low-speed recording of the future high-speed recording disc. Even at this time, it is possible to correct a precise edge shift, and it is possible to cope with various optical disks having different recording film materials or recording mechanisms without changing the basic waveform of the recording strategy.

In order to perform the above operation, the optical disc apparatus of the present embodiment is supplied with electric power from the outside via the terminal 160.

It is explanatory drawing which shows the recording strategy in the optical disk recording method of this invention corresponding to the modulation | alteration of RLL (1, 7). It is explanatory drawing which shows the recording strategy in the conventional recording method corresponding to the modulation | alteration of LL (2, 10). It is explanatory drawing which shows the recording pulse of 2Tw in 3rd Embodiment of the optical disk recording method of invention. It is a block diagram which shows one specific example of the optical disk apparatus in this invention. It is a comparison table of each modulation system of RLL (1, 7) and RLL (2, 10) when the transfer time T per bit of a user is 24 ns. 2 is a table illustrating a reference table of parameters related to a leading pulse in the first embodiment shown in FIG. 1. 2 is a table illustrating a reference table of parameters related to a final pulse in the first embodiment illustrated in FIG. 1. It is a table | surface which illustrates the reference table of the parameter regarding the recording pulse of 2Tw in the 2nd Embodiment of this invention. It is a table | surface which illustrates the reference table of the parameter regarding the last pulse in the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Optical disk, 110 ... Spindle motor, 112 ... Chucking mechanism, 115
... guide rail, 116 ... feed motor, 117 ... optical pickup, 121 ... objective lens actuator, 131 ... semiconductor laser, 132 ... collimator lens, 133 ... beam splitter, 134 ... detection lens, 135 ... photodetector, 136 ... objective lens , 150 ... system controller, 151 ... servo controller, 152 ... amplifier, 153 ... decoder, 1
54 ... Signal processing circuit, 155 ... Delay circuit, 156 ... Current sink, 157 ... Constant current source, 15
8 ... Output terminal, 159 ... Input terminal, 160 ... Power supply terminal, 161 ... Signal processing circuit, 170 ...
Binarization circuit.

Claims (3)

With respect to an optical disc provided with a recording film capable of recording information by being changed into an optically different form by irradiating the energy beam, the energy beam has at least two light emission power levels, and the energy beam is recorded on the optical disc. Information is recorded as the length of the recording mark and the length of the space in the optically different form by moving in the film plane and irradiating in a plurality of pulses while changing the light emission time of each power level. An optical disc recording method for recording
A set value related to the emission time of the plurality of energy beam pulses is expressed as a sum of a linear term and a constant term with respect to a reference clock , and the coefficient of the linear term and the coefficient of the constant term are each defined as an integer,
Corresponding the position of the head pulse to the recording mark length and the previous space length, the coefficient of the linear term with respect to the reference clock is held in the first table,
Each of the coefficient of the linear term and the coefficient of the constant term with respect to the reference clock is held in the second table with the width of the head pulse corresponding to the recording mark length and the previous space length,
An optical disk recording method, wherein information is recorded by changing a position and a width of the head pulse based on the first and second tables. An optical disc apparatus capable of recording information on an optical disc as the length of a recording mark and the length of a space by irradiating the energy beam in a plurality of pulses while changing the emission time of each power level,
An energy beam generator;
Power adjusting means capable of setting the emission power of the energy beam generated by the energy beam generator to at least two predetermined power levels;
A holding mechanism for holding the optical disc;
Moving means capable of relatively moving the energy beam within the recording film surface of the optical disc;
Conversion means for converting information to be recorded into a power level change of the energy beam;
Storage means for holding a set value relating to emission control of the energy beam;
A set value related to the emission time of the plurality of energy beam pulses is expressed as a sum of a linear term and a constant term with respect to a reference clock , and a coefficient of the linear term and a coefficient of the constant term are each defined as an integer,
The storage means stores the position of the head pulse in correspondence with the recording mark length and the previous space length, holds the coefficient of the linear term with respect to the previous reference clock as a reference table, and the width of the head pulse corresponds to the recording mark length and the previous space length. The linear term coefficient and the constant term coefficient with respect to the reference clock are held as reference tables, respectively.
The optical disk apparatus according to claim 1, wherein the power adjustment means controls the timing of the light emission pulse while referring to the reference tables. A recording film that can be optically changed to an optically different form by irradiation of an energy beam, wherein the optical beam is irradiated in a plurality of pulses by changing the emission time of each power level of the energy beam having at least two emission power levels. An optical disc on which information is recorded as the length of a recording mark and the length of a space in different forms,
The set values related to the emission times of the plurality of energy beam pulses are expressed as a sum of a linear term and a constant term with respect to a reference clock , and the coefficient of the linear term and the coefficient of the constant term are defined to be integers. ,
A table that prescribes a setting value relating to the position of the leading pulse as a coefficient of a linear term with respect to the reference clock corresponding to the recording mark length and the previous space length;
A table that prescribes a set value related to the width of the leading pulse as a coefficient of a linear term and a coefficient of a constant term with respect to the reference clock corresponding to the recording mark length and the previous space length;
An optical disc characterized by the above.

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