JP4044742B2 - Recording / reproducing method and recording / reproducing apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a recording / reproducing method and a recording / reproducing apparatus, and more particularly to a recording / reproducing method and a recording / reproducing apparatus for erasing or rewriting a recording mark recorded on a rewritable recording medium.
[0002]
[Prior art]
Examples of the rewritable recording medium include a phase change medium and a magneto-optical medium. The phase change medium records a recording mark by a difference in atomic state. For example, in a phase change optical disk as a phase change medium, the erasure part is in a crystallized state and the recording part is in an amorphous state.
[0003]
Phase change optical discs irradiate laser light of high power (hereinafter referred to as “recording laser power”) to raise the temperature of the recording layer to the melting point or higher to disorder the atomic arrangement, and this disordered state is lowered to room temperature by rapid cooling. Thus, an amorphous recording mark is recorded. The phase change optical disk reproduces a recording mark by irradiating a laser beam with low power (hereinafter referred to as “reproducing laser power”) and detecting a difference in reflected light intensity.
[0004]
Conventionally, a phase change optical disk has an atomic arrangement by raising the recording layer to a temperature higher than the crystallization temperature and lower than the melting point by irradiating a medium power (hereinafter referred to as “erasing laser power”) laser beam in a direct current (DC) manner. Ordered and recorded amorphous recording marks were erased or rewritten.
[0005]
[Problems to be solved by the invention]
However, the phase change optical disk is not completely crystallized even if the laser beam of the erasing laser power is irradiated only once in a direct current when the laser scanning speed exceeds the crystallization speed for removing the recording layer. In other words, it is difficult to erase or rewrite a recording mark once recorded at high speed.
[0006]
Further, the recording and erasing characteristics of the phase change optical disk greatly depend on the relative speed between the laser beam and the disk surface because the crystallization speed and the amorphization speed of the recording layer are determined by the disk. That is, in order to erase or rewrite the recorded recording mark at high speed, it is necessary to produce a phase change optical disk with high recording sensitivity and high crystallization speed.
[0007]
The present invention has been made in view of the above points, and erases or rewrites a recording mark recorded on a rewritable recording medium at high speed without newly creating a recording medium having high recording sensitivity and high crystallization speed. It is an object of the present invention to provide a recording / reproducing method and a recording / reproducing apparatus capable of performing the above.
[0008]
[Means for Solving the Problems]
Therefore, in order to solve the above problems, the present invention records a recording mark on a rewritable recording medium, and irradiates the recording mark at least once to reproduce the recording mark recorded on the recording medium. When the recording mark is erased in a direct current with the intensity for erasing the recording mark, it is inversely proportional to the number of times of irradiation for completely erasing the recording mark, and the diameter of the spot size of the laser beam irradiated on the recording medium. A laser beam modulated with one or more pulses whose pulse intervals are determined in proportion to each other is irradiated, and the already recorded recording mark is erased.
[0009]
In the present invention, the intensity of laser light that erases the recording mark by irradiating at least once is modulated with one or more pulses, and the recording mark is irradiated with the laser light modulated with one or more pulses. The record mark can be erased by one irradiation. Therefore, the recording mark recorded on the rewritable recording medium can be erased or rewritten at high speed.
[0010]
Further, the present invention provides a recording mark recorded on a rewritable recording medium, and the recording mark is recorded on the recording medium in order to reproduce the recording mark recorded on the recording medium. A recording stage in which a laser beam modulated with a pulse is irradiated to a recording position of the recording mark, and an intensity at which the recording mark is erased by irradiating the recording mark at least once, and is modulated with one or more pulses. And an erasing step of irradiating the laser beam to a position other than the recording position of the recording mark, and the one or more pulses in the erasing step erase the recording mark in a direct current with an intensity for erasing the recording mark. when, inversely proportional to the number of times of irradiation for erasing completely said recording marks, to characterized in that the pulse interval is determined by the relationship that is proportional to the diameter of the spot size of the laser beam irradiated on the recording medium .
[0011]
In the present invention, the recording mark is recorded by modulating the laser beam having the intensity for recording the recording mark with one or more pulses and irradiating the recording position of the recording mark with the laser beam modulated with one or more pulses. it can.
[0012]
Further, the intensity of the laser beam that erases the recording mark by irradiating one or more times is modulated by one or more pulses, and the recording mark is irradiated with the laser beam modulated by one or more pulses. The recording mark can be erased by irradiation.
[0013]
Therefore, it is possible to directly rewrite a new recording mark while erasing an already recorded recording mark by modulating with one or more pulses without creating a new recording medium with high recording sensitivity. It becomes.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. In this embodiment, an example in which a recording mark recorded on a phase change optical disk is erased or rewritten will be described as an example of a rewritable recording medium. However, any rewritable recording medium may be used.
[0015]
First, in order to facilitate understanding of the present invention, a recording process for recording a recording mark on a phase change optical disk and an erasing process for erasing the recording mark recorded on the phase change optical disk will be described with reference to the drawings.
[0016]
FIG. 1 is a diagram illustrating an example of a recording process. For example, when a phase change optical disc is irradiated with laser light having a recording laser power as shown in FIG. 1A, a recording mark having a shape as shown in FIG. 1B is recorded. The recording mark is in an amorphous state. When the recording mark as shown in FIG. 1B is irradiated with a laser beam having a reproduction laser power, a reproduction signal waveform as shown in FIG. 1C is obtained due to the difference in reflected light intensity between the amorphous state and the crystallized state. Can do.
[0017]
FIG. 2 is a diagram illustrating an example of an erasing process. When a phase change optical disk on which a recording mark as shown in FIG. 1B is recorded with a laser power of 9 mW, for example, is irradiated with a laser beam having an erasing laser power as shown in FIG. A completely uncrystallized state as shown in FIG. 2B is obtained. Therefore, when the recording mark as shown in FIG. 2B is irradiated with a laser beam having a reproduction laser power of 0.6 mW, the output level is reduced as shown in FIG. A signal waveform can be obtained.
[0018]
When a phase change optical disc on which a recording mark as shown in FIG. 1B is recorded is irradiated with a laser beam with an erasing laser power of 4.5 mW as shown in FIGS. 2D and 2E. The recording mark is not completely crystallized but remains in an unerased state as shown in FIG. Therefore, when the recording mark as shown in FIG. 2 (F) is irradiated with a laser beam having a reproduction laser power of 0.6 mW, the output level is reduced as compared with FIG. 2 (C) as shown in FIG. 2 (G). A signal waveform can be obtained.
[0019]
Further, a laser beam with an erasing laser power of 4.5 mW as shown in FIGS. 2 (H), 2 (I) and 2 (J) is applied to a phase change optical disk on which a recording mark as shown in FIG. 1 (B) is recorded. Is irradiated in a direct current, the recording mark is almost completely crystallized. That is, the recording mark as shown in FIG. 1B is completely erased as shown in FIG. Therefore, even if a laser beam having a reproduction laser power of 0.2 mW is irradiated, the reproduction signal waveform is not output as shown in FIG.
[0020]
In FIG. 2, by irradiating the phase change optical disc on which the recording mark is recorded with a laser beam of, for example, 4.5 mW of erasing laser power only once, a part of the amorphous recording mark is crystallized. Furthermore, by irradiating the phase change optical disk on which the recording mark is recorded with laser light of 4.5 mW erasing laser power twice or three times, the amorphous part of the recording mark is reduced and the crystallization part is increased. I will do it. As a result, the recording mark as shown in FIG. 1B is completely crystallized as shown in FIG.
[0021]
Hereinafter, the number of direct-current irradiations of laser light having an erasing laser power of, for example, 4.5 mW necessary for bringing an amorphous recording mark into a crystallized state will be referred to as a necessary number of DC erasing. For example, as shown in FIG. 2, when an amorphous recording mark is crystallized by irradiating a laser beam with an erasing laser power of 4.5 mW three times in a direct current, the number of DC erasures required is three. .
[0022]
When the amorphous recording mark becomes a crystallized state by irradiating the laser beam with the erase laser power of 4.5 mW twice or more in a direct current manner, the erase laser power of 4.5 mW or a slightly higher level of 4.8 is obtained. By using a laser beam modulated with an erasing laser power of about ~ 5.0 mW and a multi-pulse of about 1.0 mW in the erasing process, an amorphous recording mark can be crystallized by one irradiation. .
[0023]
FIG. 3 is a diagram for explaining an example of an erasing process using laser light modulated by multipulses. A laser beam as shown in FIG. 3A modulated with a multi-pulse of erasing laser power or a slightly higher erasing laser power is applied to the recording mark 20 of FIG. 3B in an alternating current (AC) manner. The large, medium, and small circles in FIG. 3B represent heat propagation, and heat is propagated from the inner small circle toward the outer large circle.
[0024]
Heat corresponding to the first laser light irradiation is given to the recording mark 20 by the first pulse, and heat corresponding to the second laser light irradiation is given to the recording mark 20 by the second pulse. With this pulse, heat corresponding to the third laser beam irradiation is applied to the recording mark 20.
[0025]
Therefore, by irradiating the recording mark 20 with the laser beam modulated by the erasing laser power or a multi-pulse of a slightly higher erasing laser power as many times as necessary for the DC erasing, the recording mark 20 can be applied to the recording mark 20 by one AC irradiation. A completely crystallized state as in (C), in other words, a completely erased state 21 can be obtained.
[0026]
The required number of DC erasures is determined using, for example, the flowchart of FIG. FIG. 4 shows a flowchart of an example for determining the required number of DC erasures.
[0027]
In FIG. 4, in step S <b> 1, a crystallization portion where no recording mark is recorded on the phase change optical disk is irradiated with a laser beam having a reproduction laser power, and a reproduction signal 0 in the crystallization state is detected. Progressing to step S2 following step S1, a phase change optical disk is irradiated with laser light of recording laser power to record an amorphous recording mark on the phase change optical disk.
[0028]
Proceeding to step S3 following step S2, the recording mark recorded on the phase change optical disc is irradiated with a laser beam of reproduction laser power to detect the reproduction signal 1 in the complete recording state.
[0029]
Progressing to step S4 following step S3, the amorphous recording mark is irradiated with a laser beam having an erasing laser power in a direct current manner so that a part or all of the recording mark is crystallized. When all of the recording marks are crystallized, the recording marks are completely erased. On the other hand, when a part of the recording mark is crystallized, the recording mark is left unerased.
[0030]
Progressing to step S5 following step S4, the reproduction signal 2 in the unerased state or in the completely erased state is obtained by irradiating the recording mark portion irradiated with the erasing laser power laser beam in a DC manner with the reproduction laser power laser beam. Is detected.
[0031]
Progressing to step S6 following step S5, it is determined whether or not the reproduction signal 0 and the reproduction signal 2 are equal. If it is determined that reproduction signal 0 and reproduction signal 2 are equal (YES in S6), the process for determining the number of DC erasures necessary is terminated. On the other hand, when it is determined that reproduction signal 0 and reproduction signal 2 are not equal (NO in S6), the process proceeds to step S7.
[0032]
In step S7, 1 is added to the required number of DC erasures, and the process proceeds to step S4. The initial value of the necessary number of DC erasures is 1. Then, steps S4 to S7 are repeated until it is determined that the reproduction signal 0 and the reproduction signal 2 are equal.
[0033]
Therefore, according to the flowchart of FIG. 4, it is possible to determine the number of DC erasures required as the number of times of direct irradiation of the laser beam having the erasing laser power necessary to bring the amorphous recording mark into a crystallized state.
[0034]
When the necessary number of DC erasures is determined, the distance D from the central portion of one pulse to the central portion of the next pulse is determined using the following equation (1) as shown in FIG. To do. R is the spot size of the laser beam.
[0035]
Distance D = (Spot size diameter 2R) ÷ (Number of required DC erasures) (1)
As described above, by determining the required number of DC erasures and the distance D, the erasing process as described with reference to FIG. 3 can be realized.
[0036]
FIG. 5 is a diagram illustrating an example of a recording process according to the present invention. For example, when a recording waveform as shown in FIG. 5A is supplied, the phase change optical disc is irradiated with a laser beam as shown in FIG. Then, a recording mark as shown in FIG. 5C is recorded on the phase change optical disk.
[0037]
5A is irradiated with a laser beam as shown in FIG. 5B modulated by a multi-pulse of the erasing laser power on a portion where the recording mark is not recorded based on the recording waveform of FIG. In this way, by irradiating the portion where the recording mark is not recorded with the laser beam as shown in FIG. 5B modulated by the multi-pulse of the erasing laser power, the recorded mark already recorded on the phase change optical disk is changed. Can be erased. That is, by irradiating the phase change optical disk with laser light as shown in FIG. 5B, direct rewriting can be performed to record a new recording mark while erasing the already recorded mark.
[0038]
FIG. 6 is a diagram illustrating an example of a direct rewriting process according to the present invention. For example, it is assumed that recording marks 30 and 31 as shown in FIG. When a recording waveform as shown in FIG. 6A is supplied, the phase change optical disc is irradiated with laser light as shown in FIG. 6B modulated by a multi-pulse of recording laser power or erasing laser power.
[0039]
Then, the laser light modulated by the multipulse of the recording laser power records the recording marks 32 and 33 on the phase change optical disk, while the laser light modulated by the multipulse of the erasing laser power is one of the recorded marks 30 and 31. Erase part.
[0040]
For example, if the presence / absence of a recording mark is made to correspond to digital data 1 or 0, it can be considered as a method of adding a multipulse of recording laser power to the digital data 1 portion and a multipulse of erasing laser power to the digital data 0 portion. . Therefore, in the present invention, the recording mark recorded on the phase change optical disk can be erased or rewritten at high speed.
[0041]
FIG. 7 shows a block diagram of an embodiment of a recording / reproducing system included in the recording / reproducing apparatus of the present invention. The recording / reproducing system 1 includes an encoder 11, a data generator 12, an erasing multipulse generator 13, a laser driver 14, an optical head 15, a phase change optical disk 16, an IV preamplifier 17, an equalization circuit 18, and a decoding. It is comprised so that the container 19 may be included.
[0042]
For example, when a recording waveform as shown in FIG. 6A is supplied to the erasing multi-pulse generator 13 via the encoder 11 and the data generator 12, the erasing multi-pulse generator 13 has the recording laser power or The recording waveform is modulated by the multi-pulse of the erasing laser power, and the laser driver 14 is controlled so that the laser light as shown in FIG.
[0043]
The laser driver 14 controls the optical head 15 so that the phase change optical disk is irradiated with laser light as shown in FIG. 6B, so that the laser light modulated by the multipulse of the recording laser power is recorded on the recording marks 32, 33 is recorded on the phase change optical disk 16, while the laser beam modulated by the multipulse of the erasing laser power erases a part of the recorded marks 30 and 31.
[0044]
When the recording marks 32 and 33 as shown in FIG. 6D are irradiated with the laser beam having the reproduction laser power, the reproduction signal corresponding to the reproduction signal waveform is converted into the IV preamplifier 17, the equalization circuit 18, and the decoder 19. Is output via.
[0045]
Therefore, in the present invention, it is possible to erase or rewrite already recorded recording marks at high speed by modulating laser light without newly creating a phase change optical disk with high recording sensitivity.
[0046]
【The invention's effect】
As described above, according to the present invention, a laser beam having an intensity for irradiating one or more times to erase a recording mark is modulated with one or more pulses, and the laser beam modulated with one or more pulses is used as a recording mark. By irradiating, the recording mark can be erased by one irradiation. Therefore, the recording mark recorded on the rewritable recording medium can be erased or rewritten at high speed.
[0047]
Further, according to the present invention, the intensity of laser light for recording a recording mark is modulated with one or more pulses, and the recording position of the recording mark is irradiated with the laser light modulated with one or more pulses. Record marks can be recorded.
[0048]
Further, the intensity of the laser beam that erases the recording mark by irradiating one or more times is modulated by one or more pulses, and the recording mark is irradiated with the laser beam modulated by one or more pulses. The recording mark can be erased by irradiation.
[0049]
Therefore, it is possible to directly rewrite a new recording mark while erasing an already recorded recording mark by modulating with one or more pulses without creating a new recording medium with high recording sensitivity. It becomes.
[0050]
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of a recording process.
FIG. 2 is a diagram illustrating an example of an erasing process.
FIG. 3 is a diagram for explaining an example of an erasing process using laser light modulated by multi-pulses.
FIG. 4 is a flowchart of an example of determining a required number of DC erasures.
FIG. 5 is a diagram illustrating an example of a recording process according to the present invention.
FIG. 6 is a diagram illustrating an example of a direct rewriting process according to the present invention.
FIG. 7 is a block diagram of an embodiment of a recording / reproducing system included in the recording / reproducing apparatus of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Recording / reproducing system 11 Encoder 12 Data generator 13 Erasing multi-pulse generator 14 Laser driver 15 Optical head 16 Phase change optical disk 17 IV preamplifier 18 Equalization circuit 19 Decoder 20, 30-33 Recording mark 21 Fully erased state

Claims (4)

In a recording / reproducing method for recording a recording mark on a rewritable recording medium and reproducing the recording mark recorded on the recording medium,
When the recording mark is erased in a direct current with the intensity to erase the recording mark by irradiating the recording mark at least once, it is inversely proportional to the number of times of irradiation for completely erasing the recording mark, and Irradiating a laser beam modulated with one or more pulses whose pulse interval is determined in a relationship proportional to the diameter of the spot size of the laser beam to be irradiated, and erasing the already recorded recording mark Recording / playback method. In a recording / reproducing method for recording a recording mark on a rewritable recording medium and reproducing the recording mark recorded on the recording medium,
A recording step of irradiating a recording position of the recording mark with a laser beam having an intensity for recording the recording mark on the recording medium and modulated by one or more pulses;
An erasing step of irradiating the recording mark other than the recording position of the recording mark with an intensity of irradiating the recording mark at least once to erase the recording mark and modulated with one or more pulses,
The one or more pulses in the erasing step are inversely proportional to the number of irradiations for completely erasing the recording mark when the recording mark is erased in a direct current with an intensity for erasing the recording mark. A recording / reproducing method characterized in that a pulse interval is determined in a relationship proportional to a diameter of a spot size of a laser beam irradiated on a medium. In a recording / reproducing apparatus for recording a recording mark on a rewritable recording medium and reproducing the recording mark recorded on the recording medium,
Laser light irradiation means for irradiating the recording medium with laser light;
Control means for controlling the laser light emitted from the laser light irradiation means,
The control means is inversely proportional to the number of irradiations for completely erasing the recording mark when the recording mark is erased in a direct current with the intensity to erase the recording mark by irradiating the recording mark at least once, The recording medium is irradiated with laser light modulated with one or more pulses whose pulse intervals are determined in proportion to the diameter of the spot size of the laser light irradiated onto the recording medium, and recorded on the recording medium. A recording / reproducing apparatus for erasing a recorded mark. In a recording / reproducing apparatus for recording a recording mark on a rewritable recording medium and reproducing the recording mark recorded on the recording medium,
Laser light irradiation means for irradiating the recording medium with laser light;
Control means for controlling the laser light emitted from the laser light irradiation means,
The control means irradiates a recording position of the recording mark with a laser beam having an intensity for recording the recording mark on a recording medium and modulated by one or more pulses, and irradiates the recording mark one or more times. When the recording mark is erased in a direct current with the intensity for erasing the recording mark, it is inversely proportional to the number of times of irradiation for completely erasing the recording mark, and proportional to the spot size diameter of the laser beam applied to the recording medium. A recording / reproducing apparatus that irradiates a laser beam modulated with one or more pulses whose pulse interval is determined in accordance with the above relationship to a position other than the recording position of the recording mark.

Images