JP2005302271A - Optical information recording method, optical information recording apparatus, and optical information recording medium - Google Patents

Abstract

When recording data on an optical information recording medium, a mark without distortion is recorded in a wide linear velocity range.
13 recording pulses are formed as recording pulse trains corresponding to a plurality of power levels including a recording power and an erasing power so that a length of a mark 604 corresponds to a recording code length of data, and the recording pulse train is a multi-pulse. It is composed of a plurality of pulses including 602 and a trailing end pulse 603. A mark is formed by irradiating a recording medium with laser light at a plurality of types of linear velocities. When the linear velocities v1 and v2 are in a relationship of v1 <v2, the following expression is satisfied. (TL1 / Tw1) <(TL2 / Tw2) and ((TM2 / Tw2) / (TM1 / Tw1)) <((TL2 / Tw2) / (TL1 / Tw1)). Tw1, Tw2: Channel clock periods at linear velocities v1, v2. TL1, TL2: Respective trailing edge pulse widths at linear velocities v1, v2. TM1, TM2: width of each multi-pulse at linear velocities v1, v2.
[Selection] Figure 6

Description

  The present invention relates to an optical information recording method and an optical information recording apparatus for a recording medium for optically recording / reproducing data. In particular, the present invention relates to improvement of a recording pulse waveform for a medium for recording at a plurality of different linear velocities.

  In recent years, optical disks, optical cards, optical tapes, and the like have been proposed and developed as optical recording media. Among them, the optical disk is attracting attention as a medium capable of recording and reproducing data with a large capacity and high density.

  For example, in the case of a phase change type optical disc, data recording / reproduction is performed as described below by laser light focused by an optical head. In recording, the recording film of the optical disc is irradiated with laser light stronger than the reproduction power (this power level is called recording power and expressed by Pw). As a result, when the temperature of the recording film rises beyond the melting point, the melted portion is rapidly cooled with the passage of the laser beam, and an amorphous mark is formed. In addition, when a laser beam is irradiated to raise the temperature of the recording film to a temperature not lower than the crystallization temperature and not higher than the melting point (this power level is referred to as erasing power, expressed as Pe), the recording film in the irradiated portion is brought into a crystalline state. Become.

  In this manner, a recording pattern including marks that are amorphous regions corresponding to data signals and spaces that are crystal regions is formed on the medium. Data is reproduced by utilizing the difference in reflectance between the crystal and the amorphous.

  As described above, in order to form a mark on the medium, it is necessary to modulate the laser light power level at least between the erasing power and the recording power to emit light. The pulse waveform used for this modulation operation is called a recording pulse. Many recording methods for forming one mark with a plurality of recording pulses are already known. The plurality of recording pulses is called a recording pulse train.

  An example of the recording pulse train is shown in FIG. A pulse at the beginning of the recording pulse train is called a front end pulse 1401, a pulse at the end is called a rear end pulse 1403, and a pulse between the front end pulse and the rear end pulse is called a multi-pulse 1402. The number of recording pulses constituting the recording pulse train varies depending on the recording code length (that is, the length of the recording code with respect to the channel clock period Tw), and the number of recording pulses may be one at the shortest code length.

  Further, there is also known a method of forming a mark with a single recording pulse in which the pulse levels of the head and the end are changed as shown in FIG. 14B instead of the recording pulse train. The leading pulse 1404 and the last pulse 1405 are also referred to as a front end pulse and a rear end pulse, respectively.

  At present, optical information recording media such as DVDs mainly use CLV (Constant Linear Velocity) recording. In this method, recording is performed with substantially the same linear velocity, transfer rate, and linear density over the entire surface of the medium. In this case, the rotational speed of the medium changes depending on the recording / reproducing position (that is, the radial position) in the medium.

  On the other hand, a CAV (equal angular velocity) recording method is also known in which the rotational speed and linear density of the medium are almost constant over the entire surface of the medium. The CAV recording method has an advantage that the spindle motor and its control circuit can be manufactured at low cost because the rotational speed control of the spindle motor that rotates the medium is unnecessary. Further, since it is not necessary to wait for the recording / reproducing operation after the seek operation at the recording / reproducing position until the predetermined rotational speed is reached, the access speed to the medium can be shortened.

  On the other hand, in this method, the linear velocity and the transfer rate change depending on the recording / reproducing position in the medium. Therefore, the irradiation condition of the laser beam and the heating / cooling condition on the medium change depending on the recording / reproducing position.

When recording on a medium at a plurality of different linear velocities, various methods are known as recording methods for improving signal quality by adjusting a recording pulse waveform. As an example, Patent Document 1 describes that a mark is formed by a recording pulse train, and the duty ratio of the multi-pulse and the trailing edge pulse is increased in accordance with the increase in the recording linear velocity (that is, the ratio of the pulse width to the channel clock period is set). Method) is disclosed. Further, for example, Patent Document 2 discloses a method for increasing the duty ratio of the front end pulse and the multipulse in accordance with an increase in the recording linear velocity. For example, Patent Document 3 discloses a method of forming a mark with a recording pulse train and increasing the duty ratio of the front end pulse in accordance with an increase in recording linear velocity.
Japanese Patent Laid-Open No. 2001-222819, page 3-5, FIG. Japanese Patent Laid-Open No. 2001-76341, page 5, FIG. JP 2001-118245 A, page 5-7, FIG.

  However, the conventional recording / reproducing method has a problem that data cannot be recorded stably with good signal quality when the range of the linear velocity to be changed is wide. The problem will be described below.

  When recording at a high linear velocity and a high transfer rate using a recording pulse train, it is necessary to shorten the channel clock cycle, which is a reference for generating the recording pulse train. However, there is a fixed rise time and fall time in the laser modulation / light emission operation.

  Therefore, in the method of increasing the duty ratio of the multi-pulse and the trailing end pulse as the linear velocity increases, the problem as shown in the waveform diagram of FIG. 15 occurs at a high linear velocity. That is, in recording at a high linear velocity, the period Tw of the channel clock signal (a) is reduced. Based on this channel clock signal, the duty ratio of the multi-pulse 1502 and the rear end pulse 1503 is changed as shown in (d) with respect to the recording pulse signal in (c) corresponding to the modulation signal in (b). As a result, the width between the pulses may be shorter than the sum of the rise time and fall time of the laser. As a result, as shown in (e), the light emission pulse cannot be modulated between the predetermined recording power Pw and the predetermined erasing power Pe.

  Further, when the laser beam based on the multi-pulse is irradiated, the recording pulse exists before and after that. For this reason, thermal energy tends to concentrate during multi-pulse recording as compared to recording front-end and rear-end pulses. As a result, even if modulation between the recording power Pw and the erasing power Pe can be performed using a high-performance laser, if the duty ratio of the multi-pulse is increased, the mark central portion corresponding to the irradiated portion of the multi-pulse becomes the front and rear portions. As a result, the mark becomes thicker and the mark shape is distorted.

  In order to avoid this problem, another problem arises when the duty ratio of the multi-pulse and the trailing edge pulse is not excessively increased at a high linear velocity. That is, in high linear velocity recording, the relative velocity between the laser spot and the medium increases. In this case, when the duty ratio of the trailing edge pulse is small, in high linear velocity recording, when the trailing edge of the mark is formed (that is, when the laser power level transitions from the recording power to the erasing power), the laser The cooling rate after melting by irradiation becomes excessively fast. As a result, the amorphous part of the rear part of the mark is formed too stably, and unerased parts are generated when the mark is overwritten, resulting in a phenomenon that the quality of the reproduction signal is lowered.

  On the other hand, when the duty ratio of the front end pulse is increased in accordance with the increase in the recording linear velocity, the duty ratio of the front end pulse is the smallest when recording at the lowest linear velocity, and the entire pulse train length is the shortest. However, in the low linear velocity recording, the relative speed between the laser spot and the medium is slow, so that the cooling rate after melting by laser irradiation is slow. As a result, there has been a problem that recrystallization proceeds from around the melted portion, the width of the front portion of the mark is reduced, the mark shape is distorted, and the quality of the reproduction signal is lowered.

  The present invention provides an optical information recording method, an optical information recording apparatus, and an optical information recording medium capable of recording / reproducing data with a stable and good signal quality over a wide linear velocity range on the same medium. Objective.

  In order to achieve the above object, the first optical information recording method of the present invention uses a laser so that the length of the mark or space formed on the optical information recording medium corresponds to the recording code length of the data. A recording pulse for driving is formed, and the recording pulse is formed as a recording pulse train having a plurality of pulse heights corresponding to a plurality of power levels including the recording power Pw and the erasing power Pe, and at least one type of the recording For the code length, the recording pulse train is composed of a plurality of pulses including a multi-pulse and a trailing end pulse, and the optical information recording medium is irradiated with laser light based on the recording pulse at a plurality of types of linear velocities. The mark or the space is formed by changing the optical characteristics of the photosensitive recording film. When two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2, the following expression is satisfied.

(TL1 / Tw1) <(TL2 / Tw2) and ((TM2 / Tw2) / (TM1 / Tw1)) <((TL2 / Tw2) / (TL1 / Tw1))
Tw1, Tw2: each channel clock period at linear velocities v1, v2 TL1, TL2: each trailing edge pulse width at linear velocities v1, v2 TM1, TM2: width of each multipulse at linear velocities v1, v2 Marks without distortion can be formed at low linear velocities, and unerased areas at the time of overwriting can be eliminated at high linear velocities, making it possible to record data with high signal quality over a wide linear velocity range. .

  In the first optical information recording method, it is preferable that TL1 = TM1. This eliminates the need to independently generate and correct only the rear end pulse at the linear velocity v1, thereby simplifying the configuration of the apparatus.

  In the first optical information recording method, instead of forming a multi-pulse, a rear end pulse is formed by making the power level Pw at the rear of the recording pulse different from the power level Pb at the center of the recording pulse. Recording pulses can also be used. In that case, instead of the above conditional expression, the following expression is satisfied.

(TL1 / Tw1) <(TL2 / Tw2) and (α2 / α1) <((TL2 / Tw2) / (TL1 / Tw1))
α1: Power level ratio at linear velocity v1, α1 = (Pw−Pb1) / (Pw−Pe)
α2: power level ratio at linear velocity v2, α2 = (Pw−Pb2) / (Pw−Pe)
Pb1: power level at the central portion of the recording pulse at the linear velocity v1 Pb2: power level at the central portion of the recording pulse at the linear velocity v2 As for the first optical information recording method, the linear velocity v1 and the linear velocity v2 When the channel clock period is T and the trailing edge pulse width is TL, the trailing edge pulse width TL is increased so as to increase (TL / T) according to the increase of the linear velocity v. May be controlled. Thereby, the light emission waveform at an intermediate linear velocity can be easily determined.

  In order to achieve the above object, the second optical information recording method of the present invention uses a laser so that the length of the mark or space formed on the optical information recording medium corresponds to the recording code length of the data. A recording pulse for driving is formed, and the recording pulse is formed as a recording pulse train having a plurality of pulse heights respectively corresponding to a plurality of power levels including the recording power Pw and the erasing power Pe. For the recording code length, the recording pulse train is composed of a plurality of pulses including a front end pulse, and the optical information recording medium is irradiated with laser light based on the recording pulses at a plurality of types of linear velocities. The mark or the space is formed by changing the optical characteristics of the recording film. When two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2, the following expression is satisfied.

(TS1 / Tw1)> (TS2 / Tw2)
Tw1, Tw2: Channel clock periods at linear velocities v1, v2 TS1, TS2: Front end pulse widths at linear velocities v1, v2 According to this method, a distortion-free mark can be formed even at low linear velocities. Data can be recorded with good signal quality over a wide linear velocity range.

  Preferably, in the second optical information recording method, the recording pulse train includes a multi-pulse following the front end pulse, and when the widths of the multi-pulses at the linear velocities v1 and v2 are TM1 and TM2, respectively (( TM1 / Tw1) / (TM2 / Tw2)) <((TS1 / Tw1) / (TS2 / Tw2)) is satisfied.

  In the second optical information recording method, instead of forming a multi-pulse, a front end pulse is formed by making the power level Pw at the front of the recording pulse different from the power level Pb at the center of the recording pulse. Recording pulses can also be used.

  In this case, preferably, the following conditional expression is satisfied instead of the conditional expression described above.

(Α2 / α1) <((TS1 / Tw2) / (TS2 / Tw1))
α1: Power level ratio at linear velocity v1, α1 = (Pw−Pb1) / (Pw−Pe)
α2: power level ratio at linear velocity v2, α2 = (Pw−Pb2) / (Pw−Pe)
Pb1: Power level at the central portion of the recording pulse at the linear velocity v1 Pb2: Power level at the central portion of the recording pulse at the linear velocity v2 Accordingly, data can be recorded with good signal quality over a wide linear velocity range.

  In the second optical information recording method, it is preferable that (TL1 / Tw1) <(TL2 / Tw2) is satisfied when the trailing edge pulse widths at the linear velocities v1 and v2 are TL1 and TL2, respectively. According to this method, data can be recorded with better signal quality over a wide linear velocity range.

  As for the second optical information recording method, when the channel speed is T and the front end pulse width is TS at the linear velocity v1 between the linear velocity v1 and the linear velocity v2, the linear velocity v The front end pulse width TS can be controlled so as to decrease (TS / T) in accordance with the increase in. Thereby, the light emission waveform at an intermediate linear velocity can be easily determined.

  Moreover, about the 1st or 2nd optical information recording method, it is preferable to record on an optical information recording medium by a CAV recording system. This makes it possible to record data with good signal quality regardless of the recording / reproducing position in the medium.

  In the first or second optical information recording method, it is preferable that the power level between the recording pulses is different from the erasing power Pe. As a result, since the cooling rate during recording can be optimally controlled according to the linear velocity, data can be recorded with better signal quality.

  In this case, it is more preferable that the power level between the recording pulses at the linear velocity v2 is higher than the power level between the recording pulses at the linear velocity v1. Thereby, since the cooling rate does not become excessive at the time of recording at a high linear velocity, the unerased portion at the time of overwriting is reduced, and it becomes possible to record data with better signal quality.

  In order to achieve the above object, a first optical information recording apparatus of the present invention includes a linear velocity setting circuit that sets different types of linear velocities when recording on an optical information recording medium, and the linear velocity. A recording pulse generating circuit for generating a recording pulse in accordance with a setting result of the setting circuit; and a laser driving circuit for irradiating a laser beam based on the recording pulse. The recording pulse generating circuit forms the recording pulse so that the length of a mark or space formed on the optical information recording medium corresponds to a recording code length of data to be recorded, and the recording pulse is The recording pulse train is formed as a recording pulse train having a plurality of pulse heights respectively corresponding to a plurality of power levels including the recording power Pw and the erasing power Pe. It is composed of a plurality of pulses including an end pulse. When two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2, the recording pulse generating circuit satisfies the following expression to satisfy the following equation: Control the width of the.

(TL1 / Tw1) <(TL2 / Tw2) and ((TM2 / Tw2) / (TM1 / Tw1)) <((TL2 / Tw2) / (TL1 / Tw1))
Tw1, Tw2: each channel clock period at linear velocities v1, v2 TL1, TL2: each trailing edge pulse width at linear velocities v1, v2 TM1, TM2: width of each multi-pulse at linear velocities v1, v2 Marks without distortion can be formed at low linear velocities, and unerased areas at the time of overwriting can be eliminated at high linear velocities, making it possible to record data with high signal quality over a wide linear velocity range. .

  In the first optical information recording apparatus, it is preferable that the recording pulse generation circuit controls the width of the trailing edge pulse so that TL1 = TM1. This eliminates the need to independently generate and correct only the rear end pulse at the linear velocity v1, thereby simplifying the configuration of the apparatus.

  In the first optical information recording apparatus, instead of forming a multi-pulse, a rear end pulse is formed by making the power level Pw at the rear of the recording pulse different from the power level Pb at the center of the recording pulse. Thus, a recording pulse can be obtained. In this case, the recording pulse generation circuit controls the width of the trailing edge pulse so as to satisfy the following expression instead of the conditional expression.

(TL1 / Tw1) <(TL2 / Tw2) and (α2 / α1) <((TL2 / Tw2) / (TL1 / Tw1))
α1: Power level ratio at linear velocity v1, α1 = (Pw−Pb1) / (Pw−Pe)
α2: power level ratio at linear velocity v2, α2 = (Pw−Pb2) / (Pw−Pe)
Pb1: power level at the central portion of the recording pulse at the linear velocity v1 Pb2: power level at the central portion of the recording pulse at the linear velocity v2 For the first optical information recording apparatus, the first linear velocity v1; At a linear velocity v between the second linear velocities v2, when the channel clock cycle is T and the trailing edge pulse width is TL, the recording pulse generator circuit (TL / The rear end pulse width can be controlled so as to increase T). Thereby, the light emission waveform at an intermediate linear velocity can be easily determined.

  In order to achieve the above object, a second optical information recording apparatus of the present invention includes a linear velocity setting circuit for setting different types of linear velocities when recording on an optical information recording medium, and the linear velocity. A recording pulse generating circuit for generating a recording pulse in accordance with a setting result of the setting circuit; and a laser driving circuit for irradiating a laser beam based on the recording pulse. The recording pulse generating circuit forms the recording pulse so that the length of a mark or space formed on the optical information recording medium corresponds to a recording code length of data to be recorded, and the recording pulse is It is formed as a recording pulse train having a plurality of pulse heights respectively corresponding to a plurality of power levels including the recording power Pw and the erasing power Pe, and the recording pulse train includes a front end pulse for at least one type of the recording code length. It consists of multiple pulses. When two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2, the recording pulse generating circuit satisfies the following expression to satisfy the following equation: Control the width of the.

(TS1 / Tw1)> (TS2 / Tw2)
Tw1, Tw2: Each channel clock period at linear velocities v1, v2 TS1, TS2: Each front end pulse width at linear velocities v1, v2 According to this apparatus, a mark without distortion can be formed at low linear velocities. Data can be recorded with good signal quality over a wide linear velocity range.

  In the second optical information recording apparatus, the recording pulse train includes a multi-pulse following the front end pulse, and when the width of the multi-pulse at the linear velocities v1 and v2 is TM1 and TM2, respectively, the recording pulse is generated. The circuit preferably controls the width of the front end pulse so as to satisfy ((TM1 / Tw1) / (TM2 / Tw2)) <((TS1 / Tw1) / (TS2 / Tw2)).

  In the second optical information recording apparatus, instead of forming a multi-pulse, a front end pulse is formed by making the power level Pw at the front of the recording pulse different from the power level Pb at the center of the recording pulse. Recording pulses can also be used.

  In this case, preferably, the recording pulse generation circuit controls the width of the front end pulse so as to satisfy the following conditional expression instead of the above conditional expression.

(Α2 / α1) <((TS1 / Tw2) / (TS2 / Tw1))
α1: Power level ratio at linear velocity v1, α1 = (Pw−Pb1) / (Pw−Pe)
α2: power level ratio at linear velocity v2, α2 = (Pw−Pb2) / (Pw−Pe)
Pb1: Power level at the central portion of the recording pulse at the linear velocity v1 Pb2: Power level at the central portion of the recording pulse at the linear velocity v2 Accordingly, data can be recorded with good signal quality over a wide linear velocity range.

  In the second optical information recording apparatus, when the trailing edge pulse widths at the linear velocities v1 and v2 are TL1 and TL2, respectively, the recording pulse generation circuit is (TL1 / Tw1) <(TL2 / Tw2) It is preferable to control the width of the trailing edge pulse so as to satisfy the above.

  In the second optical information recording apparatus, the recording pulse is generated when the channel clock period is T and the front end pulse width is TS at the linear velocity v1 between the linear velocity v1 and the linear velocity v2. The circuit may be configured to control the front end pulse width TS so as to decrease (TS / T) in accordance with an increase in the linear velocity v. Thereby, the light emission waveform at an intermediate linear velocity can be easily determined.

  In order to achieve the above object, the optical information recording medium of the present invention is used for recording by the first optical information recording method or the second optical information recording method. Information representing the value of TL2 or information representing the values of TS1 and TS2 is recorded.

  Further, in the linear velocity v between the linear velocity v1 and the linear velocity v2, when the channel clock cycle is T and the trailing edge pulse width is TL, (TL / T ) Is used to record data by an optical information recording method for controlling the trailing edge pulse width TL so that the information for determining the TL is recorded.

  Alternatively, in the linear velocity v between the linear velocity v1 and the linear velocity v2, assuming that the channel clock period is T and the front end pulse width is TS, according to the increase of the linear velocity v, (TS / T ) Is used to record data by an optical information recording method for controlling the front end pulse width TS so that the information for determining the TS is recorded.

  According to the optical information recording medium having the above configuration, the pulse width corresponding to the linear velocity can be determined immediately after the medium is mounted on the optical information recording apparatus.

  According to the optical information recording method of the present invention, an undistorted mark can be formed at a low linear velocity, and the unerased portion at the time of overwriting can be eliminated at a high linear velocity. Data can be recorded with good signal quality.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

(Embodiment 1)
First, the schematic configuration of the optical information recording apparatus according to Embodiment 1 will be described with reference to the block diagram of FIG. Although FIG. 1 shows an optical information recording / reproducing apparatus, the embodiment of the present invention is characterized by the configuration of the recording apparatus portion of this apparatus. The basic configuration of the optical information recording apparatus shown in FIG. 1 is common to the following embodiments.

  Reference numeral 1 denotes an optical disk for recording / reproducing data, and reference numeral 2 denotes a system control circuit for controlling the entire recording / reproducing apparatus. Based on the signal supplied from the system control circuit 2, the modulation circuit 3 generates a binarized modulation signal 12 according to the data to be recorded. The recording pulse generation circuit 4 generates a recording pulse signal 13 for driving the laser in accordance with the modulation signal 12 output from the modulation circuit 3. Each recording pulse signal is output as a recording pulse signal 14 whose width and edge position are corrected by the recording pulse correction circuit 5.

  The laser drive circuit 6 modulates the current for driving the laser in the optical head 7 based on the recording pulse signal 14 output from the recording pulse correction circuit 5 and the power setting signal 16 supplied from the system control circuit 2. The optical head 7 focuses the laser beam 15 and irradiates the optical disc 1. The optical disc 1 has its linear velocity (that is, the rotational speed) controlled by the linear velocity setting circuit 8. A spindle motor 9 rotates the optical disc 1. A reproduction signal based on the reflected light from the optical disk 1 is subjected to waveform processing by the reproduction signal processing circuit 10 and supplied to a demodulation circuit 11 for obtaining reproduction data.

  Next, features of the optical information recording method and the optical information recording apparatus according to Embodiment 1 will be described with reference to the flowchart of FIG. 2 and the operation diagrams of FIGS.

  FIG. 2 shows a recording procedure according to the optical information recording method of the present embodiment. FIG. 3 shows a signal waveform and a recording pattern on a track when recording is performed at a low linear velocity by the same method. 4 and 5 show signal waveforms and recording patterns when the width of the trailing edge pulse is changed when recording is performed at a low linear velocity. FIG. 6 shows a signal waveform and a recording pattern when recording is performed at a high linear velocity.

  3 to 6 show the operation as an example of recording a mark having a code length of 5T. T is equal to the channel clock period Tw. In this embodiment, a recording pulse train composed of a total of three recording pulses is used to record 5T. When recording a code length other than 5T, the number of recording pulses and / or the total length of the recording pulse train is changed according to the increase or decrease of the code length.

  3 and 6, (a) is the channel clock signal, (b) is the waveform of the modulated signal 12 (see FIG. 1), (c) is the waveform of the recording pulse signal 13, and (d) is corrected. The waveform of the recording pulse signal 14, (e) shows the emission waveform of the laser beam 15. The recording pulse signal 13 is composed of a recording pulse train composed of front end pulses 301 and 601, multi-pulses 302 and 602, and rear end pulses 303 and 603, respectively. (F) shows a recording pattern on the track 304 on which the mark 305 or 604 is recorded by the laser beam 15. 4 and 5, (a) shows the emission waveform of the laser beam 15, and (b) shows the recording pattern on the track 304 on which the mark 401 or 501 is recorded.

  First, the operation of recording data in particular in the case of recording at the low linear velocity v1 in this embodiment (that is, recording at a low transfer rate) will be described with reference to the flowchart of FIG.

  At the time of recording, first, the linear velocity setting circuit 8 controls the number of revolutions of the spindle motor 9 based on the command of the system control circuit 2 by a linear velocity setting step (step S201, hereinafter, “step” is omitted). The optical disk 1 is rotated at a predetermined linear velocity. Next, in the seek operation step (S202), the optical head 7 (see FIG. 1) is positioned in a predetermined recording area on the optical disc 1.

  Next, in the power determination step (S203), the system control circuit 2 determines the optimum recording power, erasing power, etc. at this linear velocity, and outputs a power setting signal 16 to the laser driving circuit 6. These power levels can be determined by performing test recording on the optical disc 1. Further, if information indicating the power level is recorded on the control track area of the optical disc 1, it may be determined by reading this information.

  Next, in the modulation step (S204), the recording data from the system control circuit 2 is modulated by the modulation circuit 3 based on the channel clock signal shown in FIG. The modulation circuit 3 outputs a modulation signal 12 shown in FIG.

  Next, in a recording pulse signal generation step (S205), the recording pulse generation circuit 4 outputs a recording pulse signal 13 shown in FIG. 3C based on the modulation signal.

  Next, in the trailing edge pulse width correction step (S206), the recording pulse correction circuit 5 corrects the width and edge position of each recording pulse constituting the recording pulse signal 13 and corrects the recording to the laser driving circuit 6. The pulse signal 14 is output. However, in the present embodiment, no correction is applied to the trailing edge pulse in the case of the low linear velocity v1.

  Next, in the laser driving step (S207), the laser driving circuit 6 modulates the power level of the laser light 15. This power level is determined by the corrected recording pulse signal 14 and the power setting signal 16 from the system control circuit 2. That is, light is emitted with the recording power Pw when the recording pulse train signal is H, and with the erasing power Pe when the recording pulse train signal is L. As a result, the power level of the light emission waveform of the laser beam 15 changes as shown in FIG.

  Next, in the recording step (S208), a mark 305 corresponding to a code length of 5T is formed on the recording track 304 by the laser beam 15 as shown in the recording pattern of FIG.

  At this low linear velocity v1, TL1 is made smaller than Tw1 in order to avoid that the mark rear part becomes thicker than the front part and the mark shape is distorted. This will be described with reference to FIGS. 4 and 5. FIG.

  4 and 5 show a state in which the melted region and the mark shape change depending on the trailing edge pulse width TL1 when recording is performed at a low linear velocity. 4 shows a laser emission waveform (a) and a recording pattern (b) when recording is performed with a small rear end pulse width TLa (corresponding to the present embodiment), and FIG. 5 is a case where recording is performed with a large rear end pulse width TLb. Show.

  When recording the rear part of the mark, the heat at the time of recording the front part of the mark is conducted to the rear part, so that heat tends to accumulate. Therefore, as shown in the melting regions 402 and 502 in FIGS. 4B and 5B, the width of the rear melting region (the width in the direction orthogonal to the track) tends to be thicker than the central portion of the mark. This tendency becomes more prominent as the linear velocity is lower.

  Therefore, when the rear end pulse width TLb is increased with respect to the channel clock period Tw as shown in FIG. 5A, recording is formed in the melted region 502 at the rear of the mark as shown in FIG. 5B. The mark 501 has a thick rear width WLb. As a result, the width WTb of the front part of the mark and the width WLb of the rear part become different, and the shape of the formed mark is distorted, and the signal quality when this mark is reproduced is lowered.

  On the other hand, as shown in FIG. 4A, when the trailing edge pulse width TLa is recorded smaller than the channel clock period Tw, as shown in FIG. 4B, as shown in FIG. Expansion is suppressed. As a result, the width WLa at the rear portion of the mark 401 is not excessively thick, and the width WTa at the front portion of the mark is equal to the width WLa at the rear portion of the mark, so that a good mark shape without distortion can be obtained. Therefore, reproduction with good signal quality is possible.

  On the other hand, in the case of recording at a high linear velocity v2 based on the present embodiment (that is, recording at a high transfer rate), the signal waveforms of each part of the apparatus are shown in FIG. Is shown in FIG.

  The difference from the case of the low linear velocity v1 is that the trailing edge pulse width TL2 is enlarged by ΔTL2 at the trailing edge in the trailing edge pulse width correction step (S206) shown in FIG. The ratio of the pulse width TL2 is set to be large. As a result, more heat is applied when the mark rear portion is formed, and after the melting, the mark is slowly cooled. As a result, it can be avoided that the amorphous becomes too stable due to an excessive cooling rate when the mark rear part is formed. Therefore, even at a high linear velocity at which the relative velocity between the laser spot and the medium becomes high, no unerasure occurs at the time of overwriting, and data can be recorded with good signal quality.

  In FIG. 3 and FIG. 6D, the duty ratios of the multi-pulses 302 and 602 are not changed in the corrected recording pulse signal 14. Therefore, even when the channel clock period Tw2 is reduced, the width between recording pulses does not become extremely small. Therefore, even in the case of a high linear velocity, the laser light can be stably modulated and emitted between the power levels. Can do. Further, since excessive thermal energy is not applied during recording at the mark center, it is possible to suppress the mark distortion that thickens the mark center.

  As described above, the main point of the present embodiment is to set so as to satisfy the following conditional expression (1) at two types of linear velocities v1 and v2 where v1 <v2.

(TL1 / Tw1) <(TL2 / Tw2) (1)
That is, the ratio of the width of the trailing edge pulse to the channel clock cycle is changed between the cases of the low linear velocity v1 and the high linear velocity v2 as shown in the relationship between FIG. 3 (e) and FIG. 6 (e). The trailing edge pulse width is relatively small at low linear velocities and relatively large at high linear velocities. As a result, a mark without distortion can be formed, and at the high linear velocity, the unerased portion at the time of overwriting can be eliminated.

  In the above example, the multi-pulse duty ratio is constant for the low linear velocity and the high linear velocity, but the multi-pulse duty ratio can be increased as the linear velocity increases. However, the increase rate of the multi-pulse width with respect to the increase rate of the linear velocity is set smaller than the increase rate of the trailing edge pulse width. If it does so, the above-mentioned effect by adjusting a back end pulse width can be acquired, suppressing mark distortion which a mark central part becomes thick enough. That is, when the multipulse width at the low linear velocity v1 is TM1 and the multipulse width at the high linear velocity v2 is TM2, the following conditional expression (2) is satisfied. Here, the multi-pulse width means the width of each individual pulse forming the multi-pulse.

((TM2 / Tw2) / (TM1 / Tw1)) <((TL2 / Tw2) / (TL1 / Tw1))
... (2)
By satisfying conditional expressions (1) and (2), a distortion-free mark can be formed even in the central portion, and at the high linear velocity, the unerased portion at the time of overwriting can be eliminated, and a wide linear velocity is achieved. Data can be recorded over a range with good signal quality.

  However, in order to simplify the configuration of the apparatus, it is preferable to keep the duty ratio of the multipulse constant.

  Note that the linear velocities v1 and v2 are extracted in order to define the mutual relationship between two types of linear velocities among a plurality of types of linear velocities. That is, it does not mean that only two types of linear velocities are used, and the method of the present embodiment can be similarly applied even when three or more types of linear velocities are used.

  In the present embodiment, if the trailing edge pulse width TL1 at the lowest linear velocity v1 is made equal to the multipulse width TM1, the trailing edge pulse at this linear velocity v1 can be generated in the same manner as the multipulse. Therefore, since it is not necessary to independently generate and correct only the trailing edge pulse at the linear velocity v1, there is a further advantage that the configuration of the apparatus can be simplified.

(Embodiment 2)
Next, the optical information recording method and the optical information recording apparatus according to the second embodiment will be described with reference to the flowchart of FIG. 7 and the operation diagrams of FIGS. The basic configuration of the optical information recording apparatus in the present embodiment is the same as that of the first embodiment shown in FIG.

  FIG. 7 shows a recording procedure according to the optical information recording method of the present embodiment. FIG. 8 shows a signal waveform and a recording pattern on a track when recording is performed at a higher linear velocity by the same method. FIG. 9 shows a signal waveform and a recording pattern when recording is performed at a low linear velocity. 10 and 11 show signal waveforms and recording patterns when the width of the front end pulse is changed when recording is performed at a low linear velocity. FIG. 8 to FIG. 11 show the operation as an example of recording a mark with a code length of 5T, as in FIG. 3 to FIG.

  8 and 9, (a) is the channel clock signal, (b) is the waveform of the modulation signal 12 (see FIG. 1), (c) is the waveform of the recording pulse signal 13, and (d) is corrected. The waveform of the recording pulse signal 14, (e) shows the emission waveform of the laser beam 15. The recording pulse signal 13 is constituted by a recording pulse train composed of front end pulses 801 and 901, multi-pulses 802 and 902, and rear end pulses 803 and 903, respectively. (F) shows a recording pattern on the track 304 after the mark 804 or 904 is recorded by the laser beam 15. 10 and 11, (a) shows the emission waveform of the laser beam 15, and (b) shows the recording pattern on the track 304 on which the mark 1001 or 1101 is recorded.

  First, an operation for recording data in particular when recording at a high linear velocity v2 in this embodiment (that is, recording at a high transfer rate) will be described with reference to the flowchart of FIG. Here, the same steps as those in the first embodiment shown in FIG. 2 are denoted by the same step reference numerals and will be described focusing on the main points.

  First, the optical head 7 is positioned in a predetermined recording area on the optical disc 1 (see FIG. 1) rotated at a predetermined linear velocity by a linear velocity setting step (S201) and a seek operation step (S202).

  Next, in the power determination step (S203), the system control circuit 2 determines the optimum recording power, erasing power, etc. at this linear velocity, and outputs a power setting signal 16 to the laser driving circuit 6. These power levels can be determined by performing test recording on the optical disc 1. Further, if information indicating the power level is recorded on the control track area of the optical disc 1, it may be determined by reading this information.

  Next, in the modulation step (S204), the recording data from the system control circuit 2 is modulated by the modulation circuit 3 based on the channel clock signal shown in FIG. The modulation circuit 3 sends out a modulation signal 12 shown in FIG.

  Next, in a recording pulse signal generation step (S205), the recording pulse generation circuit 4 outputs a recording pulse signal 13 shown in FIG. 8C based on the modulation signal. Up to this point, the operation is the same as in the first embodiment.

  Next, in the front end pulse width correction step (S701), the recording pulse correction circuit 5 corrects the width and edge position of each recording pulse constituting the recording pulse signal 13 and corrects the recording pulse to the laser driving circuit 6. The signal 14 is output. However, in the present embodiment, no correction is applied to the front end pulse in the case of the high linear velocity v2.

  Next, in the laser driving step (S207), the laser driving circuit 6 modulates the power level of the laser light 15. This power level is determined by the corrected recording pulse signal 14 and the power setting signal 16 from the system control circuit 2. That is, light is emitted with the recording power Pw when the recording pulse train signal is H, and with the erasing power Pe when the recording pulse train signal is L. As a result, the power level of the light emission waveform of the laser beam 15 changes as shown in FIG.

  Next, in the recording step (S208), as shown in FIG. 8F, a mark 804 corresponding to a code length of 5T is formed on the recording track 304 by the laser beam 15.

  On the other hand, in the case of recording at a low linear velocity v1 (that is, recording at a low transfer rate) based on the present embodiment, signal waveforms of respective parts of the apparatus are shown in FIGS. Is shown in FIG.

  Unlike the case of the high linear velocity, in the front end pulse width correction step (S701), the front end pulse width TS1 is enlarged by ΔTS1 at the front end edge so as to increase the ratio of the front end pulse width TS1 to the channel clock period Tw1. Is to set. As a result, when recording is performed at a low linear velocity v1, it is possible to suppress the recrystallization after melting and the width of the mark front portion from being reduced. This will be described with reference to FIG. 10 and FIG.

  10 and 11 show a state in which the melted region and the mark shape change depending on the front end pulse width TS1 when recording at a low linear velocity. FIG. 10 shows a laser emission waveform (a) and a recording pattern (b) when recording is performed with a small front end pulse width TSc, and FIG. 11 is a case when recording is performed with a large front end pulse width TSd (corresponding to the present embodiment).

  As for the front part of the mark, the laser continues to emit light at the recording power even after the front part of the mark is formed (that is, the irradiation energy remains high), so the temperature after melting is unlikely to decrease. Therefore, as shown in FIG. 10B, the width of the formed mark 1001 tends to be smaller than the width of the melted region 1002. This tendency becomes more prominent as recording is performed at a lower linear velocity. As a result, the width WTc at the front part of the mark is different from the width WLc at the rear part, the shape of the formed mark is distorted, and the signal quality when the mark is reproduced is lowered.

  On the other hand, when the front end pulse width is increased with respect to the channel clock period Tw as shown in FIG. 11A, recording is performed corresponding to the mark front portion of the melted area 1102 as shown in FIG. It is compensated that the portion is enlarged and the width of the mark 1101 to be formed becomes narrow. As a result, a good mark shape is obtained in which the width WTd of the mark front part and the width WLd of the mark rear part are equal and have no distortion. Therefore, reproduction with good signal quality is possible.

  As described above, the main point of the present embodiment is to set so as to satisfy the following conditional expression (3) between the cases of the low linear velocity v1 and the high linear velocity v2.

(TS1 / Tw1)> (TS2 / Tw2) (3)
In other words, the ratio of the width of the front end pulse to the channel clock period is changed as shown in the relationship between FIG. 8 (e) and FIG. 9 (e), and the front end pulse width is relatively large at a low linear velocity. Let's make it relatively small. As a result, a distortion-free mark can be formed at a low linear velocity, and data can be recorded with good signal quality over a wide linear velocity range.

  Furthermore, the duty ratio of the multipulse can be increased as the linear velocity decreases. However, the increase rate of the multi-pulse width with respect to the linear velocity reduction rate is made smaller than the increase rate of the front end pulse. Then, like the above-described first embodiment, it is possible to suppress the mark distortion in which the mark center portion becomes thick. That is, when the multipulse width at the low linear velocity v1 is TM1 and the multipulse width at the high linear velocity v2 is TM2, the following conditional expression (4) is satisfied.

((TM1 / Tw1) / (TM2 / Tw2)) <((TS1 / Tw1) / (TS2 / Tw2))
... (4)
However, in order to simplify the configuration of the apparatus, it is preferable to keep the duty ratio of the multipulse constant.

(Embodiment 3)
In the above two embodiments, the case of recording at two types of linear velocities, the low linear velocity v1 and the high linear velocity v2, has been shown. However, in the CAV recording method, the linear velocity and the transfer rate depend on the recording / reproducing position in the medium. It changes continuously. In such a case, it is preferable to determine the light emission waveform at the intermediate linear velocity by smoothly connecting the light emission waveform at the low linear velocity v1 and the light emission waveform at the high linear velocity v2. The present embodiment is an example in which the optical information recording method of the first or second embodiment is configured in such a manner.

  FIG. 12 shows an example of setting the trailing edge pulse width when the linear velocity is continuously changed and recorded in the range from v1 to v2 in the first embodiment. At the linear velocity v1, light is emitted with the light emission waveform of the laser light shown in FIG. 3E, that is, the ratio of the width of the trailing edge pulse to the channel clock cycle (TL1 / Tw1). At the linear velocity v2, light is emitted with the light emission waveform shown in FIG. 6E, that is, the ratio of the width of the trailing edge pulse to the channel clock cycle (TL2 / Tw2). Then, the ratio of the rear end pulse width to the channel clock period is smoothly changed between the ratio (TL1 / Tw1) at the linear velocity v1 and the ratio (TL2 / Tw2) at v2. This change may be linear as shown in FIG. 12, may be connected by a smooth curve that changes monotonously, or may change monotonically and stepwise. However, it is desirable to set the ratio of the trailing edge pulse width to the channel clock period to increase as the linear velocity increases.

  Similarly, FIG. 13 shows an example of setting the front end pulse width when recording is performed by continuously changing the linear velocity in the range from v1 to v2 in the second embodiment. Similar to the configuration shown in FIG. 12, the ratio of the front end pulse width to the channel clock period is smoothly changed between the ratio (TS1 / Tw1) at the linear velocity v1 and the ratio (TS2 / Tw2) at v2. At this time, it is desirable to set so that the ratio of the front end pulse width to the channel clock period decreases as the linear velocity increases.

  In the embodiment in which the recording pulse width is changed according to the linear velocity as shown in FIGS. 12 and 13, the simplest method for determining the recording pulse width at the linear velocity between v1 and v2 is the linear velocity v1, v2. Is a method of interpolating and determining a recording pulse width at a desired linear velocity based on the recording pulse width in each of the above.

(Embodiment 4)
In each of the above-described embodiments, as shown in FIG. 14A, an example in which a multi-pulse is provided between a front end pulse and a rear end pulse to form a recording pulse train is shown. On the other hand, as shown in FIG. 14B, a recording pulse can be configured with a constant power level Pb between the front end pulse and the rear end pulse. Even in this case, data can be similarly recorded with good signal quality if the front end pulse width and the rear end pulse width are changed according to the relationship as in the above-described embodiments.

  Although it is desirable for the power level Pb between the front end pulse and the rear end pulse to be fixed in order to simplify the configuration of the apparatus, the power level Pb can be changed as the linear velocity changes. However, the change rate of the power level Pb with respect to the change rate of the linear velocity is set smaller than the change rate of the trailing edge pulse width. If it does so, the above-mentioned effect by adjusting a back end pulse width or a front end pulse width can be acquired, suppressing mark distortion which a mark central part becomes thick enough. The conditions for setting the rate of change of the power level Pb will be described below.

  The power level ratio α is defined by the following formula (5) with respect to the recording power Pw, the erasing power Pe, and the power level Pb.

α = (Pw−Pb) / (Pw−Pe) (5)
According to this definition, the power level ratio α and the multi-pulse duty ratio are energetically equivalent. The power level ratio α1 at the linear velocity v1 and the power level ratio α2 at the linear velocity v2 are as shown in the following equations (6) and (7).

α1 = (Pw−Pb1) / (Pw−Pe) (6)
α2 = (Pw−Pb2) / (Pw−Pe) (7)
In the equation, Pb1 indicates the power level at the center of the recording pulse at the linear velocity v1, and Pb2 indicates the power level at the center of the recording pulse at the linear velocity v2.

  For the power level ratios α1 and α2, in the case of the configuration corresponding to the first embodiment, the power level Pb is set so as to satisfy the following conditional expression (8).

(Α2 / α1) <((TL2 / Tw2) / (TL1 / Tw1)) (8)
In the case of the configuration corresponding to the second embodiment, the power level Pb is set so as to satisfy the following conditional expression (9).

(Α2 / α1) <((TS1 / Tw1) / (TS2 / Tw2)) (9)
Thereby, similarly to the case of the multi-pulse, it is possible to suppress the mark distortion in which the mark center part becomes thick.

  In the above embodiment, one of the rear end pulse width and the front end pulse width is changed with respect to the linear velocity. However, both pulse widths can be changed simultaneously as described above. preferable. In this case, there is an advantage that data can be recorded with higher signal quality over a wide linear velocity range.

  Further, in each of the above embodiments, the optimum value of the front end pulse width or the rear end pulse width in v1 and v2 may be determined from test recording. In this case, there is an advantage that the best pulse width can be determined according to the type of medium and the state of the apparatus.

  Alternatively, if the front end pulse width or rear end pulse width in v1 and v2 is recorded on the control track of the recording medium (that is, the area for recording information on the recording medium), the recording medium is mounted on the optical information recording apparatus. After that, there is an advantage that the pulse width corresponding to the linear velocity can be determined immediately. This power level information may be recorded on a medium by an optical information recording apparatus, or may be recorded in advance when the medium is manufactured.

  Further, in each of the above embodiments, the power level of the laser emission waveform is changed at two levels of Pw and Pe, but may be changed between three or more levels. For example, the power level (also referred to as bottom level) between the recording pulses may be higher than Pe or lower than Pe. Here, the power level between the recording pulses is set so as to increase as the linear velocity increases, so that the cooling rate does not become excessive at the time of recording at a high linear velocity, and the unerased portion at the time of overwriting is not increased. It is more preferable in terms of reduction.

  In each of the above-described embodiments, the same effect as described above can be obtained even when a recording pulse train is formed by adding a cooling pulse after a recording pulse or recording pulse train.

  The recording pulse modulation method, the length and position of each pulse, etc. are not limited to those shown in the above-described embodiments, and can be set appropriately according to the recording conditions and the medium. . Further, the edge position of the recording pulse can be corrected in order to avoid the influence of thermal interference between marks.

  The above method can be applied to any optical disk as long as it has a different optical characteristic between the mark and space, such as a phase change material, a magneto-optical material, or a dye material.

  Furthermore, even when the optical information recording method, optical information recording apparatus, and optical information recording medium of the present invention are applied to a personal computer, server, recorder, etc., the same effects as described above can be obtained.

  An optical information recording method, an optical information recording apparatus, and an optical information recording medium according to the present invention are, for example, a rewritable / write-once information recording medium such as a DVD or a BD (Blue-ray Disk) recording medium, or a magneto-optical recording medium. In addition, it is useful for applications such as information recording apparatuses and methods for these media.

1 is a block diagram showing a configuration of an optical information recording / reproducing apparatus according to an embodiment of the present invention. The flowchart which shows the procedure of the optical information recording method which concerns on Embodiment 1 of this invention. The figure which shows the signal waveform and recording pattern in an example which records a mark by modulating a laser beam at a low linear velocity by the recording method The figure which shows the signal waveform and recording pattern which show the problem at the time of modulating the laser beam in the case of low linear velocity and recording the mark The figure which shows the signal waveform and recording pattern which show the problem at the time of modulating the laser beam in the case of low linear velocity and recording the mark FIG. 6 is a diagram showing a signal waveform and a recording pattern in an example of recording a mark by modulating laser light in high linear velocity recording in the first embodiment. Flowchart showing the procedure of the optical information recording method according to the second embodiment of the present invention. The figure which shows the signal waveform and recording pattern in an example which records a mark by modulating a laser beam at a high linear velocity by the recording method The figure which shows the signal waveform and recording pattern in an example which records a mark by modulating a laser beam at low linear velocity in Embodiment 2. The figure which shows the signal waveform and recording pattern which show the problem at the time of modulating the laser beam in the case of low linear velocity and recording the mark The figure which shows the signal waveform and recording pattern which show the problem at the time of modulating the laser beam in the case of low linear velocity and recording the mark The figure explaining the change of the back end pulse width with respect to the linear velocity in the optical information recording method concerning Embodiment 3 The figure explaining the change of the front end pulse width with respect to the linear velocity in the same optical information recording method Waveform diagram for explaining a recording pulse in the fourth embodiment The figure which shows the signal waveform and recording pattern in the case of recording a mark by modulating a laser beam at a high linear velocity in the conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 2 System control circuit 3 Modulation circuit 4 Recording pulse generation circuit 5 Recording pulse correction circuit 6 Laser drive circuit 7 Optical head 8 Linear velocity setting circuit 9 Spindle motor 10 Reproduction signal processing circuit 11 Demodulation circuit 12 Modulation signal 13 Recording pulse signal 14 Corrected recording pulse signal 15 Laser light 16 Power setting signal 301, 601, 801, 901, 1401, 1404, 1501 Front end pulse 302, 602, 802, 902, 1402, 1502 Multi-pulse 303, 603, 803, 903, 1403 1405, 1503 Rear end pulse 304 Track 305, 401, 501, 604, 804, 904, 1001, 1101 Mark 402, 502, 1002, 1102 Melting region

Claims (30)

Forming a recording pulse for driving the laser so that the length of the mark or space formed on the optical information recording medium corresponds to the recording code length of the data;
The recording pulse is formed as a recording pulse train having a plurality of pulse heights corresponding to a plurality of power levels including the recording power Pw and the erasing power Pe,
For at least one type of the recording code length, the recording pulse train is composed of a plurality of pulses including a multi-pulse and a trailing end pulse,
Optical information recording for forming the mark or the space by irradiating the optical information recording medium with laser light based on the recording pulse at a plurality of types of linear velocities to change the optical characteristics of the photosensitive recording film A playback method,
An optical information recording method characterized by satisfying the following equation when two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2.
(TL1 / Tw1) <(TL2 / Tw2) and ((TM2 / Tw2) / (TM1 / Tw1)) <((TL2 / Tw2) / (TL1 / Tw1))
Tw1, Tw2: each channel clock period at linear velocities v1, v2 TL1, TL2: each trailing edge pulse width at linear velocities v1, v2 TM1, TM2: width of each multi-pulse at linear velocities v1, v2   2. The optical information recording method according to claim 1, wherein TL1 = TM1. Forming a recording pulse for driving the laser so that the length of the mark or space formed on the optical information recording medium corresponds to the recording code length of the data;
The recording pulse is formed to have a plurality of pulse heights corresponding to a plurality of power levels including the recording power Pw and the erasing power Pe,
For at least one type of the recording code length, the rear pulse level is formed by making the power level Pw at the rear of the recording pulse different from the power level Pb at the center of the recording pulse,
Optical information recording for forming the mark or the space by irradiating the optical information recording medium with laser light based on the recording pulse at a plurality of types of linear velocities to change the optical characteristics of the photosensitive recording film A playback method,
An optical information recording method characterized by satisfying the following equation when two types of linear velocities v1 and v2 of the plurality of types of linear velocities have a relationship represented by v1 <v2.
(TL1 / Tw1) <(TL2 / Tw2) and (α2 / α1) <((TL2 / Tw2) / (TL1 / Tw1))
Tw1, Tw2: Channel clock periods at linear velocities v1, v2 TL1, TL2: Respective end pulse widths at linear velocities v1, v2 α1: Power level ratio at linear velocity v1, α1 = (Pw−Pb1) / (Pw− Pe)
α2: power level ratio at linear velocity v2, α2 = (Pw−Pb2) / (Pw−Pe)
Pb1: Power level at the center of the recording pulse at the linear velocity v1 Pb2: Power level at the center of the recording pulse at the linear velocity v2 In the linear velocity v between the linear velocity v1 and the linear velocity v2,
When the channel clock cycle is T and the trailing edge pulse width is TL,
4. The optical information recording method according to claim 1, wherein the trailing edge pulse width TL is controlled to increase (TL / T) in accordance with an increase in the linear velocity v. 5. Forming a recording pulse for driving the laser so that the length of the mark or space formed on the optical information recording medium corresponds to the recording code length of the data;
Forming the recording pulse as a recording pulse train having a plurality of pulse heights respectively corresponding to a plurality of power levels including a recording power Pw and an erasing power Pe;
For at least one type of the recording code length, the recording pulse train is composed of a plurality of pulses including a front end pulse,
Optical information recording for forming the mark or the space by irradiating the optical information recording medium with laser light based on the recording pulse at a plurality of types of linear velocities to change the optical characteristics of the photosensitive recording film A playback method,
An optical information recording method characterized by satisfying the following equation when two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2.
(TS1 / Tw1)> (TS2 / Tw2)
Tw1, Tw2: Channel clock periods at linear velocities v1, v2 TS1, TS2: Front end pulse widths at linear velocities v1, v2 The recording pulse train includes a multi-pulse following the front end pulse,
When the widths of the multipulses at the linear velocities v1 and v2 are TM1 and TM2, respectively.
((TM1 / Tw1) / (TM2 / Tw2)) <((TS1 / Tw1) / (TS2 / Tw2))
The optical information recording method according to claim 5, wherein: Forming a recording pulse for driving the laser so that the length of the mark or space formed on the optical information recording medium corresponds to the recording code length of the data;
The recording pulse is formed to have a plurality of pulse heights corresponding to a plurality of power levels including the recording power Pw and the erasing power Pe,
For the recording code length of at least one kind, the front end pulse is formed by making the power level Pw of the front part of the recording pulse different from the power level Pb of the central part of the recording pulse,
Optical information recording for forming the mark or the space by irradiating the optical information recording medium with laser light based on the recording pulse at a plurality of types of linear velocities to change the optical characteristics of the photosensitive recording film A playback method,
An optical information recording method characterized by satisfying the following equation when two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2.
(TS1 / Tw1)> (TS2 / Tw2)
Tw1, Tw2: Channel clock periods at linear velocities v1, v2 TS1, TS2: Front end pulse widths at linear velocities v1, v2 The optical information recording method according to claim 7, wherein the following formula is satisfied.
(Α2 / α1) <((TS1 / Tw2) / (TS2 / Tw1))
α1: Power level ratio at linear velocity v1, α1 = (Pw−Pb1) / (Pw−Pe)
α2: power level ratio at linear velocity v2, α2 = (Pw−Pb2) / (Pw−Pe)
Pb1: Power level at the center of the recording pulse at the linear velocity v1 Pb2: Power level at the center of the recording pulse at the linear velocity v2 When the trailing edge pulse widths at the linear velocities v1 and v2 are TL1 and TL2, respectively.
(TL1 / Tw1) <(TL2 / Tw2)
The optical information recording method according to any one of claims 5 to 8, wherein: In the linear velocity v between the linear velocity v1 and the linear velocity v2,
When the channel clock period is T and the front end pulse width is TS,
The optical information recording method according to any one of claims 5 to 8, wherein the front end pulse width TS is controlled so as to decrease (TS / T) in accordance with an increase in the linear velocity v.   11. The optical information recording method according to claim 4, wherein recording is performed on an optical information recording medium by a CAV recording method.   The optical information recording method according to any one of claims 1, 3, 5, and 7, wherein a power level between the recording pulses is different from the erasing power Pe.   The optical information recording method according to claim 12, wherein a power level between the recording pulses at a linear velocity v2 is higher than a power level between the recording pulses at a linear velocity v1. A linear velocity setting circuit for setting different types of linear velocities when recording on an optical information recording medium;
A recording pulse generating circuit for generating a recording pulse according to a setting result of the linear velocity setting circuit;
A laser drive circuit for irradiating a laser beam based on the recording pulse,
The recording pulse generating circuit forms the recording pulse so that a length of a mark or space formed on the optical information recording medium corresponds to a recording code length of data to be recorded;
Forming the recording pulse as a recording pulse train having a plurality of pulse heights respectively corresponding to a plurality of power levels including a recording power Pw and an erasing power Pe;
An optical information recording apparatus configured to form the recording pulse train with a plurality of pulses including a multi-pulse and a rear end pulse for at least one type of the recording code length,
When two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2, the recording pulse generating circuit satisfies the following expression to satisfy the following equation: An optical information recording apparatus for controlling the width of the optical information recording apparatus.
(TL1 / Tw1) <(TL2 / Tw2) and ((TM2 / Tw2) / (TM1 / Tw1)) <((TL2 / Tw2) / (TL1 / Tw1))
Tw1, Tw2: each channel clock period at linear velocities v1, v2 TL1, TL2: each trailing edge pulse width at linear velocities v1, v2 TM1, TM2: width of each multi-pulse at linear velocities v1, v2 The recording pulse generation circuit includes:
TL1 = TM1
The optical information recording apparatus according to claim 14, wherein a width of the rear end pulse is controlled so that A linear velocity setting circuit for setting different types of linear velocities when recording on an optical information recording medium;
A recording pulse generating circuit for generating a recording pulse according to a setting result of the linear velocity setting circuit;
A laser drive circuit for irradiating a laser beam based on the recording pulse,
The recording pulse generating circuit forms the recording pulse so that a length of a mark or space formed on the optical information recording medium corresponds to a recording code length of data to be recorded;
The recording pulse is formed to have a plurality of pulse heights respectively corresponding to a plurality of power levels including a recording power Pw and an erasing power Pe,
An optical information recording apparatus that forms a trailing end pulse by making a power level Pw at the rear part of the recording pulse different from a power level Pb at a central part of the recording pulse for at least one kind of the recording code length. And
When two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2, the recording pulse generating circuit satisfies the following expression to satisfy the following equation: An optical information recording apparatus for controlling the width of the optical information recording apparatus.
(TL1 / Tw1) <(TL2 / Tw2) and (α2 / α1) <((TL2 / Tw2) / (TL1 / Tw1))
Tw1, Tw2: Channel clock periods at linear velocities v1, v2 TL1, TL2: Respective end pulse widths at linear velocities v1, v2 α1: Power level ratio at linear velocity v1, α1 = (Pw−Pb1) / (Pw− Pe)
α2: power level ratio at linear velocity v2, α2 = (Pw−Pb2) / (Pw−Pe)
Pb1: Power level at the center of the recording pulse at the linear velocity v1 Pb2: Power level at the center of the recording pulse at the linear velocity v2 In the linear velocity v between the linear velocity v1 and the linear velocity v2,
When the channel clock cycle is T and the trailing edge pulse width is TL,
The recording pulse generation circuit includes:
17. The optical information recording apparatus according to claim 14, wherein the trailing edge pulse width is controlled so as to increase (TL / T) in accordance with an increase in linear velocity v. A linear velocity setting circuit for setting different types of linear velocities when recording on an optical information recording medium;
A recording pulse generating circuit for generating a recording pulse according to a setting result of the linear velocity setting circuit;
A laser drive circuit for irradiating a laser beam based on the recording pulse,
The recording pulse generating circuit forms the recording pulse so that a length of a mark or space formed on the optical information recording medium corresponds to a recording code length of data to be recorded;
Forming the recording pulse as a recording pulse train having a plurality of pulse heights respectively corresponding to a plurality of power levels including a recording power Pw and an erasing power Pe;
An optical information recording apparatus that configures the recording pulse train with a plurality of pulses including a front end pulse for at least one type of the recording code length,
When two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2, the recording pulse generating circuit satisfies the following expression to satisfy the following equation: An optical information recording apparatus for controlling the width of the optical information recording apparatus.
(TS1 / Tw1)> (TS2 / Tw2)
Tw1, Tw2: Channel clock periods at linear velocities v1, v2 TS1, TS2: Front end pulse widths at linear velocities v1, v2 The recording pulse train includes a multi-pulse following the front end pulse,
When the widths of the multipulses at the linear velocities v1 and v2 are TM1 and TM2, respectively.
The recording pulse generation circuit includes:
((TM1 / Tw1) / (TM2 / Tw2)) <((TS1 / Tw1) / (TS2 / Tw2))
The optical information recording apparatus according to claim 18, wherein the width of the front end pulse is controlled so as to satisfy the above. A linear velocity setting circuit for setting different types of linear velocities when recording on an optical information recording medium;
A recording pulse generating circuit for generating a recording pulse according to a setting result of the linear velocity setting circuit;
A laser drive circuit for irradiating a laser beam based on the recording pulse,
The recording pulse generating circuit forms the recording pulse so that the length of a mark or space formed on the optical information recording medium corresponds to a recording code length of data to be recorded;
The recording pulse is formed to have a plurality of pulse heights respectively corresponding to a plurality of power levels including a recording power Pw and an erasing power Pe,
An optical information recording apparatus that forms a front end pulse by making the power level Pw of the front part of the recording pulse different from the power level Pb of the central part of the recording pulse for at least one kind of the recording code length. And
When two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2, the recording pulse generating circuit satisfies the following expression to satisfy the following equation: An optical information recording apparatus for controlling the width of the optical information recording apparatus.
(TS1 / Tw1)> (TS2 / Tw2)
Tw1, Tw2: Channel clock periods at linear velocities v1, v2 TS1, TS2: Front end pulse widths at linear velocities v1, v2 21. The optical information recording apparatus according to claim 20, wherein the recording pulse generation circuit controls the width of the front end pulse so as to satisfy the following expression.
(Α2 / α1) <((TS1 / Tw2) / (TS2 / Tw1))
α1: Power level ratio at linear velocity v1, α1 = (Pw−Pb1) / (Pw−Pe)
α2: power level ratio at linear velocity v2, α2 = (Pw−Pb2) / (Pw−Pe)
Pb1: Power level at the center of the recording pulse at the linear velocity v1 Pb2: Power level at the center of the recording pulse at the linear velocity v2 When the trailing edge pulse widths at the linear velocities v1 and v2 are TL1 and TL2, respectively.
The recording pulse generation circuit includes:
(TL1 / Tw1) <(TL2 / Tw2)
The optical information recording apparatus according to any one of claims 18 to 21, wherein a width of the rear end pulse is controlled so as to satisfy the following equation. In the linear velocity v between the linear velocity v1 and the linear velocity v2,
When the channel clock period is T and the front end pulse width is TS,
The recording pulse generation circuit includes:
The optical information recording apparatus according to any one of claims 18 to 21, wherein the front end pulse width TS is controlled to decrease (TS / T) in accordance with an increase in the linear velocity v. Forming a recording pulse for driving the laser so that the length of the mark or space formed on the optical information recording medium corresponds to the recording code length of the data;
The recording pulse is formed as a recording pulse train having a plurality of pulse heights corresponding to a plurality of power levels including the recording power Pw and the erasing power Pe,
For at least one type of the recording code length, the recording pulse train is composed of a plurality of pulses including a multi-pulse and a trailing end pulse,
The optical information recording medium is irradiated with laser light based on the recording pulse at a plurality of types of linear velocities to change the optical characteristics of the photosensitive recording film to form the mark or the space,
When two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2, this is used for recording data by an optical information recording method that satisfies the following equation: And
An optical information recording medium on which information representing the values of TL1 and TL2 is recorded.
(TL1 / Tw1) <(TL2 / Tw2) and ((TM2 / Tw2) / (TM1 / Tw1)) <((TL2 / Tw2) / (TL1 / Tw1))
Tw1, Tw2: each channel clock period at linear velocities v1, v2 TL1, TL2: each trailing edge pulse width at linear velocities v1, v2 TM1, TM2: width of each multi-pulse at linear velocities v1, v2 Forming a recording pulse for driving the laser so that the length of the mark or space formed on the optical information recording medium corresponds to the recording code length of the data;
The recording pulse is formed to have a plurality of pulse heights corresponding to a plurality of power levels including the recording power Pw and the erasing power Pe,
For at least one type of the recording code length, the rear pulse level is formed by making the power level Pw at the rear of the recording pulse different from the power level Pb at the center of the recording pulse,
The optical information recording medium is irradiated with laser light based on the recording pulse at a plurality of types of linear velocities to change the optical characteristics of the photosensitive recording film to form the mark or the space,
When two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2, this is used for recording data by an optical information recording method that satisfies the following equation: And
An optical information recording medium on which information representing the values of TL1 and TL2 is recorded.
(TL1 / Tw1) <(TL2 / Tw2) and (α2 / α1) <((TL2 / Tw2) / (TL1 / Tw1))
Tw1, Tw2: Channel clock periods at linear velocities v1, v2 TL1, TL2: Respective end pulse widths at linear velocities v1, v2 α1: Power level ratio at linear velocity v1, α1 = (Pw−Pb1) / (Pw− Pe)
α2: power level ratio at linear velocity v2, α2 = (Pw−Pb2) / (Pw−Pe)
Pb1: Power level at the center of the recording pulse at the linear velocity v1 Pb2: Power level at the center of the recording pulse at the linear velocity v2 Furthermore, in the linear velocity v between the linear velocity v1 and the linear velocity v2,
When the channel clock cycle is T and the trailing edge pulse width is TL,
Used to record data by an optical information recording method for controlling the trailing edge pulse width TL so as to increase (TL / T) according to the increase of the linear velocity v,
26. The optical information recording medium according to claim 24, wherein information for determining the TL is recorded. Forming a recording pulse for driving the laser so that the length of the mark or space formed on the optical information recording medium corresponds to the recording code length of the data;
Forming the recording pulse as a recording pulse train having a plurality of pulse heights respectively corresponding to a plurality of power levels including a recording power Pw and an erasing power Pe;
For at least one type of the recording code length, the recording pulse train is composed of a plurality of pulses including a front end pulse,
The optical information recording medium is irradiated with laser light based on the recording pulse at a plurality of types of linear velocities to change the optical characteristics of the photosensitive recording film to form the mark or the space,
When two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2, this is used for recording data by an optical information recording method that satisfies the following equation: And
An optical information recording medium in which information representing the values of TS1 and TS2 is recorded.
(TS1 / Tw1)> (TS2 / Tw2)
Tw1, Tw2: Channel clock periods at linear velocities v1, v2 TS1, TS2: Front end pulse widths at linear velocities v1, v2 Forming a recording pulse for driving the laser so that the length of the mark or space formed on the optical information recording medium corresponds to the recording code length of the data;
The recording pulse is formed to have a plurality of pulse heights corresponding to a plurality of power levels including the recording power Pw and the erasing power Pe,
For the recording code length of at least one kind, the front end pulse is formed by making the power level Pw of the front part of the recording pulse different from the power level Pb of the central part of the recording pulse,
The optical information recording medium is irradiated with laser light based on the recording pulse at a plurality of types of linear velocities to change the optical characteristics of the photosensitive recording film to form the mark or the space,
When two types of linear velocities v1 and v2 of the plurality of types of linear velocities are in a relationship represented by v1 <v2, this is used for recording data by an optical information recording method that satisfies the following equation: And
An optical information recording medium in which information representing the values of TS1 and TS2 is recorded.
(TS1 / Tw1)> (TS2 / Tw2)
Tw1, Tw2: Channel clock periods at linear velocities v1, v2 TS1, TS2: Front end pulse widths at linear velocities v1, v2 Furthermore, when the trailing edge pulse widths at the linear velocities v1 and v2 are TL1 and TL2, respectively,
(TL1 / Tw1) <(TL2 / Tw2)
Used to record data by an optical information recording method satisfying
29. The optical information recording medium according to claim 27 or 28, wherein information representing values of the TL1 and the TL2 is recorded. Furthermore, in the linear velocity v between the linear velocity v1 and the linear velocity v2,
When the channel clock period is T and the front end pulse width is TS,
Used to record data by an optical information recording method for controlling the front end pulse width TS so as to decrease (TS / T) in response to an increase in the linear velocity v;
29. The optical information recording medium according to claim 27 or 28, wherein information for determining the TS is recorded.

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