JP2005116015A - Method and device of rewriting information on phase change optical recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize rewriting the information continuously with the power the most suitable for the recording material which is degraded by rewriting on a phase change optical recording medium. <P>SOLUTION: By using a β detection means to detect the β representing the difference of the amplitude centers of the longest and the shortest recording marks both formed in the recording area, β<SB>1</SB>at the position to start data writing and β<SB>opc</SB>at the OPC performing position after the OPC are performed (S1) and compared (S2). If β<SB>1</SB>>β<SB>opc</SB>as the result of comparing (yes in S2), actual writing is started (S5) after controlling the write power (S3) and similarly controlling the erase power (S4), and then storing the control information in the register. If β<SB>1</SB>>β<SB>opc</SB>is not satisfied (no in S2), writing is started (S5) without controlling the write power and the erase power. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a phase change optical recording medium information rewriting method and a phase change optical recording medium information rewriting apparatus for optically recording, reproducing and erasing information by irradiating a phase change optical recording medium with laser light. In particular, the present invention relates to a laser output power setting control technique at the time of information rewriting.

  In recent years, along with the evolution of optical technology, music CDs (CDs) and CD-ROMs are read-only optical discs, write-once optical discs using dye-based media, or rewritable CDs using phase change recording materials. -RW (Rewritable) has been put into practical use.

  Further, by shortening the wavelength of a semiconductor laser as a laser light source, reducing the spot diameter by using a high NA objective lens, or adopting a thin substrate, DVD (Digital Versatile Disk) -ROM, DVD + R (Recordable), DVD + RW (Rewritable) ) And other large-capacity optical recording disks are attracting attention.

  In any of the optical discs, an optical information optical disc recording / reproducing apparatus including an optical pickup optical system using a semiconductor laser as a light source is used to record information. For example, information is recorded on a phase change optical recording medium. As a general recording waveform (light emission waveform), there is a single pulse light emission waveform generated based on a recording modulation method such as an EFM (Eight to Fourteen Modulation) modulation code or an 8-16 modulation code (single pulse). Recording method).

  However, in the case of such a single pulse recording method, the recording mark is distorted like tears due to heat storage, or the amorphous phase is insufficiently formed due to insufficient cooling speed, and the recording mark is low in reflection with respect to the laser beam. There is a problem that cannot be obtained. Therefore, in general, when information is recorded on a phase change type medium, a multi-pulse waveform method in which a mark is formed by a pulse train composed of one or a plurality of short pulse groups may be used.

  A pulse emission rule such as a pulse width or an amplitude of each pulse constituting a short pulse group for recording a mark coincident with a light emission waveform based on a recording modulation method such as an EFM modulation code or an 8-16 modulation code is defined as a recording strategy. Call. A leading heating pulse FP (Front Pulse) for sufficiently preheating the recording film of the phase change type media to the melting point or more, a last heating pulse LP (Last Pulse), a plurality of continuous pulses following FP and immediately before LP It consists of a combination of a heating pulse MP (Multi Pulse) and a cooling pulse CP (Cooling Pulse) following the end pulse of the pulse group. LP and MP may not exist depending on the mark length to be recorded.

  According to such a multi-pulse light emission waveform, the mark portion of the phase change type medium has an amorphous phase formed by the rapid cooling condition of heating → cooling by the heating pulses FP, MP, LP and the cooling pulse CP, and the space portion is erased. Since the crystal phase is formed under the gradual cooling condition with only heating by the pulse, a sufficient reflectance difference is obtained between the amorphous phase and the crystal phase.

  In general, it is known that the recording quality of a phase change optical disc changes depending on the number of rewrites (Direct Over Write = DOW). In the present invention, a jitter value is used as a reference indicating whether the recording quality is good or bad. The lower the jitter value, the better the recording quality.

  In general, the jitter bottom value is lowest in the case of DOW0, the jitter bottom value is high in the case of DOW1, and in the case of DOW2 and DOW100, the jitter bottom value is often between DOW0 and DOW1. In addition, it is known that the recording power at which the jitter bottom value is obtained varies depending on the number of DOWs. In order to record at the jitter bottom value, the highest recording power is required in the case of DOW1.

  The reason why the recording quality deteriorates at the first DOW is as follows. That is, when producing a phase change type optical disc, the recording medium is made uniform by the initialization process at the factory in order to crystallize the recording material. The recording quality is good for DOW0 when recording is performed, but in the recording medium once written by the recording device, the portion written by the factory and the portion written by the recording device are mixed Will do. However, since the recording conditions are different between the factory and the recording apparatus, it is estimated that the recording quality deteriorates in the DOW 1 in which writing is further performed on the optical disk in this state.

  From the above, in the phase change type optical recording medium, it becomes a problem to improve Jitter in the case of DOW1 and the case where the number of times of DOW increases to about 1000. As techniques relating to the rewriting of information in a phase change optical recording medium, the inventions described in Patent Documents 1 and 2 can be exemplified.

In the rewriting method described in Patent Document 2, overwriting test recording is performed in a test recording area, and a reference unerased modulation degree is calculated and held from a detection signal of reflected light in the erasing area erased by a light beam with erasing power. When recording information, the peak value and the bottom value are obtained from the detection signal of the reflected light in the erasure area, the unmodulated modulation degree is calculated from the peak value and the bottom value, and the calculated unerased modulation degree is used as the reference unerased modulation degree. If the erasing power is weak by changing the erasing power so that it approaches, the erasing power can be increased to secure a good error rate for reading the signal in the overwrite recording part, and if the erasing power is strong The erasing power is lowered so as not to impair the life of the rewritable optical disk.
JP 2002-358645 A JP 2003-45031 A

  In the rewriting method described in Patent Document 2, when the characteristics of the recording / reproducing signal differ depending on the recording medium, for example, the same optical disc recording / reproducing is performed on the same type of recording medium such as 2.4X compatible DVD + RW and 4X compatible DVD + RW. It can be recorded by the device, but due to the difference in the corresponding linear velocity, when the recording sensitivity or the RF signal characteristics at the time of recording / reproduction are different, it is easily influenced by the characteristics of the recording medium and difficult to apply easily. There is a possibility.

  SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art and to always perform phase change type optical recording medium capable of rewriting with the optimum laser output power corresponding to the degree of deterioration due to rewriting of the recording material of the phase change recording medium. An object is to provide an information rewriting method and apparatus.

  In order to achieve the above object, the invention according to claim 1 is an information rewriting in an optical recording medium device for optically recording, reproducing and erasing information by irradiating a phase change type optical recording medium with laser light. A method of controlling the laser output power during recording or erasing within an appropriate range in accordance with a change in a recording material characteristic state in a phase change optical recording medium. The laser output power can be optimized by changing the recording power or the ratio of the recording power and the erasing power in accordance with the recording material characteristics of the changeable optical recording medium.

  According to a second aspect of the present invention, in the phase change optical recording medium information rewriting method according to the first aspect, the change in the recording material characteristic state is detected based on the number of rewrites of the phase change optical recording medium. With this method, the laser output power can be optimized by changing the recording material characteristics of the phase change optical recording medium, that is, the recording power or the ratio of the recording power and the erasing power according to the number of DOWs. it can.

  According to a third aspect of the present invention, in the phase change optical recording medium information rewriting method according to the first aspect, the change in the recording material characteristic state is based on the change in the RF signal characteristic of the reproduction signal in the phase change optical recording medium. By this method, the optimum output power can be determined based on the detection result of the RF characteristic of the reproduction signal, for example, β, and the recording / reproduction can be controlled.

  According to a fourth aspect of the present invention, in the phase change type optical recording medium information rewriting method according to the third aspect, the longest recording mark acquired based on the RF signal of the reproduction signal that fluctuates according to the change in the laser output power. It is determined whether or not the β value representing the difference between the amplitude center value and the amplitude center value of the shortest recording mark is within a predetermined range, and the β value is determined to be within the predetermined range. This method is characterized in that the laser output power is controlled, and this method is used to control the laser output power when the β value falls within a predetermined range by paying attention to the β value of the RF characteristics of the reproduction signal. It can be carried out.

  According to a fifth aspect of the present invention, in the method for rewriting information on a phase change optical recording medium according to the third or fourth aspect, the laser output power is changed by a laser in a test writing area of the phase change optical recording medium. According to the comparison result between the β value of the area where the optimum recording power is obtained based on the RF signal characteristics of the reproduction signal of the area that has been written and tested and the area where recording of information is to be started The laser output power is controlled, and by this method, the recording at the time of recording is performed by comparing the β value between the data area where information is to be recorded and the area where the trial writing is performed immediately after the trial writing operation. It becomes possible to control the power or the ratio of the recording power and the erasing power.

The invention according to claim 6 is the phase change optical recording medium information rewriting method according to claim 4 or 5, wherein the β value (β ₁ ) of the area where recording of information is to be started, The laser output power is controlled when the β value (β _OPC ) satisfies β ₁ > β _OPC . With this method, the power is controlled so that good recording quality can be obtained even in the case of DOW1.

According to a seventh aspect of the invention, in the phase change optical recording medium information rewriting method according to the sixth aspect, the recording power for recording on the phase change optical recording medium when the condition of β ₁ > β _OPC is satisfied. was a _{P w,} when the laser output power determined by trial writing and _{P opc,} characterized in that performing recording at a recording power condition that _{0.85 × P opc ≦ P w <} P opc, by this method, Power control is performed so that good recording quality can be obtained.

The invention according to claim 8 is the phase change optical recording medium information rewriting method according to claim 6, wherein the recording power (P _w ) for recording on the phase change optical recording medium and the erasing power (P _e ) for erasing are recorded. ) Is ε (= P _e / P _w ), ε when satisfying the condition of β ₁ > β _OPC is ε _opt, and ε when not satisfying the condition of β ₁ > β _OPC is ε _{When def} , erasing is performed with an erasing power of 0.9 × ε _def ≦ ε _opt <ε _def , and this method provides good recording quality from DOW1 to a portion close to DOW1000. can get.

  The invention according to claim 9 is the phase change optical recording medium information rewriting method according to any one of claims 1 to 8, wherein the phase change is performed when recording is performed on the phase change optical recording medium. Recording is performed at the maximum recording linear velocity that can be supported by the specifications of the type optical recording medium, and the laser output power control as described above is performed by this method, so that the maximum corresponding line of the phase change type optical recording medium is achieved. Even if recording is performed at a speed, recording can always be performed with good recording quality regardless of the number of DOWs.

  The invention according to claim 10 sets an optical unit for optically recording, reproducing and erasing information by irradiating a phase change optical recording medium with laser light, and a laser light source for emitting the laser light. A phase change optical recording medium information rewriting device comprising a laser drive unit that drives with the laser output power and a setting control unit that sets the laser output power, the recording material in the phase change optical recording medium A detection unit that detects change information of a characteristic state, wherein the setting control unit receives detection data from the detection unit, and sets the laser output power at the time of recording or erasing within an appropriate range, With this configuration, the laser output power can be optimized by changing the recording power or the ratio of the recording power and the erasing power according to the recording material characteristics of the phase change optical recording medium. .

  According to an eleventh aspect of the present invention, in the phase change optical recording medium information rewriting device according to the tenth aspect, the detection unit detects a change in the recording material characteristic state based on the number of rewrites of the phase change optical recording medium. This configuration optimizes the laser output power by changing the recording material characteristics of the phase change optical recording medium, that is, the recording power or the ratio of the recording power and the erasing power according to the number of DOWs. It can be performed.

  According to a twelfth aspect of the present invention, in the phase change optical recording medium information rewriting device according to the tenth aspect, the detection unit detects the change in the recording material characteristic state and the RF signal characteristic of the reproduction signal in the phase change optical recording medium. According to this configuration, the optimum output power can be determined based on the detection result of the RF characteristic of the reproduction signal, for example, β, and the recording / reproduction can be controlled.

  According to a thirteenth aspect of the present invention, in the phase change optical recording medium information rewriting device according to the twelfth aspect, the detection unit is acquired based on an RF signal of a reproduction signal that varies in accordance with a change in laser output power. It is determined whether or not the β value representing the difference between the amplitude center value of the longest recording mark and the amplitude center value of the shortest recording mark is within a predetermined range, and the β value is within the predetermined range. When this is determined, the setting control unit controls the laser output power. With this configuration, paying attention to the β value of the reproduction signal RF characteristics, the β value falls within a predetermined range. In some cases, the laser output power can be controlled.

  According to a fourteenth aspect of the present invention, in the phase change optical recording medium information rewriting device according to the twelfth or thirteenth aspect, the laser output power is changed by a laser in the trial writing area of the phase change optical recording medium. A trial writing unit for performing writing, and a β value of an area where the optimum recording power is obtained based on the RF signal characteristics of the reproduction signal of the trial written area, and a β value of an area where recording of information is to be started The setting control unit controls the laser output power based on the comparison result by the detection unit, and with this configuration, the data area in which information is to be recorded and the trial writing immediately after the trial writing operation were performed. The write power at the time of recording or the ratio between the recording power and the erasing power can be controlled by the comparison result of the β value with the area.

The invention according to claim 15 is the phase change type optical recording medium information rewriting device according to claim 13 or 14, wherein the β value (β ₁ ) of the area where recording of information is to be started, When the β value (β _OPC ) satisfies β ₁ > β _OPC , the setting control unit controls the laser output power. With this configuration, the power is obtained so that good recording quality can be obtained even in the case of DOW1. Be controlled.

According to a sixteenth aspect of the present invention, in the phase change optical recording medium information rewriting device according to the fifteenth aspect, the recording power for recording on the phase change optical recording medium when the condition of β ₁ > β _OPC is satisfied. was a _{P w,} when the laser output power determined by trial writing and _{P opc, 0.85 × P opc ≦} P w < setting control unit the power control so that the recording by the recording power conditions that _{P opc} is performed With this configuration, power control is performed so as to obtain good recording quality.

According to a seventeenth aspect of the present invention, in the phase change optical recording medium information rewriting device according to the fifteenth aspect, the recording power (P _w ) for recording on the phase change optical recording medium and the erasing power (P _e ) for erasing. ) Is ε (= P _e / P _w ), ε when the condition of β ₁ > β _OPC is satisfied is ε _opt, and ε when the condition of β ₁ > β _OPC is not satisfied is ε _def , The setting control unit performs power control so that erasing is performed with an erasing power of 0.9 × ε _def ≦ ε _opt <ε _def , and with this configuration, from the case of DOW 1, DOW 1000 Good recording quality can be obtained up to a portion close to.

  The invention according to claim 18 is the phase change optical recording medium information rewriting device according to any one of claims 10 to 17, wherein the phase change is performed when recording is performed on the phase change optical recording medium. Recording is performed at the maximum recording linear velocity that can be supported by the specifications of the type optical recording medium, and by this configuration, the maximum output line of the phase change type optical recording medium is achieved by performing the laser output power control as described above. Even if recording is performed at a speed, recording can always be performed with good recording quality regardless of the number of DOWs.

  According to the present invention, the laser output power is optimized by changing the recording power (write power) or the ratio of the write power and the erase power (erase power) according to the recording material characteristics of the phase change optical recording medium. It can be performed. In addition, the write power or erase power is appropriately controlled by estimating the number of DOWs based on the β value. Therefore, rewriting can always be performed with the optimum laser output power corresponding to the degree of deterioration due to rewriting of the recording material of the phase change recording medium. There is an effect that the life of the changeable optical recording medium is not impaired.

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

  FIG. 1 is a block diagram schematically showing the configuration of an optical disc recording / reproducing apparatus for explaining an embodiment of the present invention. In an optical disk recording / reproducing apparatus, a phase change optical recording medium 1 such as a DVD + RW is rotationally driven by a spindle motor 2. The spindle motor 2 that rotationally drives the phase-change optical recording medium 1 is connected to the motor driver 3 and the servo so that the phase-change optical recording medium 1 rotates according to the ZCLV (Zone Continuous Line Velocity) method or the CLV (Continuous Line Velocity) method. Drive control is performed by means 4.

  An optical pickup 5 having a light source that emits laser light to the rotationally driven phase change optical recording medium 1 emits laser light from a light source such as a laser diode, and this laser light is phase-changed by an objective lens. Focusing and tracking are performed by focusing on the recording surface of the optical recording medium 1 and driving the actuator by each of the servo means of focus servo and track servo mounted on the recording surface, and recorded on the phase change type optical recording medium 1 The reproduction data is reproduced to obtain a reproduction signal, and the information data is recorded on the phase change type optical recording medium 1.

  At the time of data reproduction, the reproduction signal obtained by the optical pickup 5 is amplified by the read amplifier 6 and binarized, and then the decoder 7 performs deinterleaving and error correction processing.

  Data from the decoder 7 is temporarily stored in the buffer RAM 9 by the buffer manager 8, and when it is prepared as sector data, the host (host computer: personal computer) via the host interface (host I / F) 10 such as ATAPI / SCSI. ) In a batch.

  At the time of data recording, data sent from the host via the host I / F 10 is temporarily stored in the buffer RAM 9 by the buffer manager 8, and then data recording is started. Before starting data recording, OPC (Optimum Power Calibration) is performed in a test writing area called PCA (Power Calibration Area) of the phase change optical recording medium 1 to obtain an optimum recording power (laser output power). Desired. Also, the disc information extracted by the disc information decoder 12 from the reproduction signal from the optical pickup 5 before writing is output to the encoder 13 to enable writing of data at an accurate position on the phase change optical recording medium 1. ing.

  Further, the data in the buffer RAM 9 is subjected to error correction code addition or interleaving in the encoder 13, and is recorded on the phase change optical recording medium 1 via the laser control circuit 14 and the optical pickup 3.

  In FIG. 1, arrows indicate directions in which data mainly flow, and in order to simplify the drawing, a connection between the CPU 15 that controls each member and each member is omitted. Connected to the CPU 15 are a ROM 16 and a RAM 17 which are memories for storing various control programs or settings and input / output data.

  FIG. 2 is a diagram showing an example of the influence on the recording quality when the write power is changed, that is, the jitter (Jitter) variation. Pw0 is the write power determined by the normal OPC operation, and the write powers Pw0 and Pw1. , Pw2 has a relationship of Pw1 <Pw0 <Pw2. When Pw1 and Pw2 are compared using Pw0 as a reference, Pw1 has a high jitter at one DOW, but then maintains a low value until the 1000th time. On the other hand, in Pw2, the jitter at the first DOW decreases, but thereafter, the jitter value increases rapidly after the tenth DOW. From this result, if it is after DOW2, if Pw1 is used as the write power, it is suitable for DOW tolerance.

  FIG. 3 is an explanatory diagram relating to the influence of the number of DOWs on the recording quality due to the difference in erase power, and the relationship between ε0 and ε1 representing the ratio between the write power and the erase power is ε0> ε1. In the case of ε0, the jitter value is not so high when DOW is 1 time, but the jitter value is higher than around DOW 100 times. On the other hand, in the case of ε1, the jitter at the time of DOW 1 time becomes high, but the increase of the jitter value at the time of DOW 100 times or more can be kept low. From this result, if it is after DOW2, if ε1 is used as the ratio of the write power and the erase power, it is suitable for the DOW resistance.

  Since the optimum write power or the ratio between the write power and the erase power changes depending on the number of DOWs of the optical disk to be recorded in this way, the laser diode mounted on the optical pickup 5 having a light source that emits laser light, etc. This can be realized by performing the above control.

  In the present embodiment, β value detection means for detecting (calculating) a β value representing a difference between the amplitude center value of the longest recording mark and the amplitude center value of the shortest recording mark formed in the recording area of the phase change optical recording medium. Is provided in the CPU 15. By this β value detection means, the low frequency component of the RF signal is removed (AC coupling), and its upper envelope level a and lower envelope level b are detected.

  FIG. 4 is an explanatory diagram of β value detection in the β value detecting means. Assuming that the reflectivity of the recording mark portion of the phase change optical recording medium 1 is lowered, the RF signal of the reproduction signal is low at the low reflection portion. Become a level. For this reason, the AC signal that is AC-coupled in the proper recording state is a = b with vertical symmetry as shown in FIG. When the recording power is excessive, the recording mark portion becomes long as shown in (b). Therefore, when AC coupling is performed, the upper level becomes high and a> b. Further, when the recording power is insufficient, as shown in (c), the recording mark portion is shortened. Therefore, when AC coupling is performed, the lower level increases and a <b.

  The amount obtained by normalizing the difference between a and b by the RF amplitude (a + b) is the β value. That is, β = (ab) / (a + b).

  In general, when recording is performed on a phase-change recording medium having the same characteristics, power is often excessive when the β value is large, and power is often insufficient when the β value is small. Thus, the laser output power can be controlled by the RF signal characteristic of the reproduction signal.

  FIG. 5 is a schematic diagram of an RF reproduction signal. In DVD + RW, 1T is one cycle of the channel clock, the longest recording mark length is 14T, and the shortest recording mark length is 3T. The peak level of 14T amplitude is I14t, the peak level of 3T amplitude is I3t, the bottom level of 14T amplitude is I14b, and the bottom level of 3T amplitude is I3b. With such an RF reproduction signal, β detection can be performed in the β value detecting means.

  FIG. 6 is a diagram showing the variation of β with respect to the number of DOWs. According to FIG. 6, β increases as the DOW increases. From this, it can be seen that the detection of the β value can be used to estimate the number of DOWs. By controlling the laser output power with a certain β value as a reference and increasing or decreasing the β value from the reference value, the write power or the ratio between the write power and the erase power can be changed.

  In general, in DVD + RW, in the test writing area (Drive test Area) in the PCA area on the inner or outer periphery of the disc, test writing is performed while changing the power in multiple stages to obtain an optimum power called OPC. The operation to determine the optimum power is performed.

  An example of the PCA area is shown in FIG. In the present embodiment, the trial writing area is divided into P001 to P100, and one area is randomly selected from these areas during OPC operation and used for OPC. For this reason, for example, after OPC is performed using P001, the probability that P001 is used when OPC is performed next is 1/100. It can be said that the test writing area of the same area is used once per OPC operation 100. In addition, after performing the OPC operation once, the area used for OPC is erased with erase power, and information is not written, so that writing is performed twice by one OPC operation. As a result, for example, if data rewriting with an OPC operation is performed 1000 times, the number of rewritings is about 20 in the test writing area.

  From the above, it is very likely that the number of rewrites is smaller in the test writing area than in the data area. This can be used to estimate the number of DOWs in the current data area. Initialization is performed before information is actually written, and data area and PCA area are written once. Therefore, when information is actually written, DOW0, that is, rewriting has not yet been performed. In this state, when the β value of the area where OPC has been performed once is compared with the β value of the data area to which information is to be written, the β value of the data area becomes lower as shown in FIG.

Next, if the data area is rewritten 10 times, the data area is DOW10, but the trial writing area is mostly DOW0 or DOW2. Using this fact, if β _{opc in} the test writing area immediately after OPC and β ₁ in the data area to which data is to be written are β _opc > β ₁ , it can be determined that the number of rewrites is 0. . Conversely, if β _opc <β _1, it can be determined that rewriting has been performed several times.

  As described above, since the optimum power in DOW1 and the optimum power after DOW2 are different, in this embodiment, the number of DOWs can be estimated. Based on the result, the write power or the write power and the erase power can be estimated. By changing the ratio, it is possible to maintain good recording quality.

From the above results, when the write power satisfies β _opc <β ₁ , 0.85 × P _opc ≦ P _w <P _opc is satisfied. If too low a write power, DOW is a 0.85 × _{P opc} ≦ _{P w} as lower write power for writing quality deteriorates when close to 1000 times. The ratio of write power to erase power is also set to 0.9 × ε _def ≦ ε _opt <ε _def when β _opc <β ₁ is satisfied. The ratio of the write power to the erase power is also set to 0.9 × ε _def ≦ ε _opt as the lower limit because mark disappearance may occur if the ratio is too low.

  Also, when recording on a phase change optical recording medium, the reproduction characteristics of the RF signal may change due to the difference in recording linear velocity corresponding to the phase change optical recording medium, that is, the maximum corresponding linear velocity. When recording is performed at 1X on a 1X phase change optical recording medium and when recording is performed at 1X on a phase change optical recording medium having a corresponding linear velocity of 1X to 4X, the β value depending on the number of DOWs Therefore, the present invention is effective at least when recording is performed at the maximum recording linear velocity corresponding to the phase change type optical recording medium.

  Recording control in the present embodiment will be described with reference to the flowchart of FIG. This control is executed by the CPU 15 in accordance with a program recorded in the ROM 16.

First, the β value detecting means detects the β value of the portion where the data in the OPC area and the data area starts to be written (S1). From the detection result, β ₁ at the part where data writing is started and β _opc at the part where OPC is performed after OPC are compared (S2).

If β ₁ > β _{opc as} a result of the comparison (yes in S2), it is determined that the portion to be recorded is not DOW0, that is, DOW1 does not become due to the next recording, and the write power is stored in the register included in the laser control circuit 14 The write power is controlled by storing the control information (S3). Subsequently, the erase power is similarly controlled (S4). After the control information is stored in the register, actual writing is started (S5).

Also, if β ₁ > β _opc is not satisfied (no in S2), there is a possibility that the portion to which data is to be written becomes DOW0, that is, DOW1 in the next recording, and if the write power or erase power is reduced, Since the jitter may deteriorate, the write power is not controlled and the write is started (S5).

  After a certain time (for example, 10 seconds) has elapsed after the start of recording (Yes in S6), the state of the phase-change optical recording medium 1 may be changed. Return to the β value measurement (S1). If there is no data to be written before the fixed time elapses (no in S6), the recording is ended (S7).

  INDUSTRIAL APPLICABILITY The present invention is applied to an optical information recording / reproducing apparatus that always performs rewriting with the optimum laser output power in accordance with the degree of deterioration due to rewriting of the recording material of the phase change recording medium, and realizes good recording and / or reproduction. This is particularly effective when recording is performed at the maximum recording linear velocity corresponding to the phase change type optical recording medium.

1 is a block diagram schematically showing the configuration of an optical disc recording / reproducing apparatus for explaining an embodiment of the present invention. The figure which shows the influence on the recording quality when the write power is changed in the phase change type optical recording medium, that is, the variation example of the jitter Explanatory diagram of the influence of the number of DOWs on the recording quality due to the difference in erase power in the phase change type optical recording medium Explanatory drawing about the β value detection of the β value detection means in this embodiment Schematic diagram of RF reproduction signal according to this embodiment The figure which shows the fluctuation | variation of (beta) with respect to the frequency | count of DOW which concerns on this embodiment. An example of the PCA area according to the present embodiment Flowchart for recording control in this embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Phase change type optical recording medium 5 Optical pick-up 6 Read amplifier 7 Decoder 8 Buffer manager 9 Buffer RAM
10 Host I / F
12 Disc information decoder 13 Encoder 14 Laser control circuit 15 CPU
16 ROM
17 RAM

Claims (18)

An information rewriting method in an optical recording medium device for optically recording, reproducing and erasing information by irradiating a phase change type optical recording medium with laser light,
A phase change optical recording medium information rewriting method, wherein control is performed to set a laser output power during recording or erasing within an appropriate range in accordance with a change in a recording material characteristic state in the phase change optical recording medium.   2. The phase change optical recording medium information rewriting method according to claim 1, wherein the change in the recording material characteristic state is detected based on the number of rewrites of the phase change optical recording medium.   2. The phase change optical recording medium information rewriting method according to claim 1, wherein a change in the recording material characteristic state is detected based on a change in an RF signal characteristic of a reproduction signal in the phase change optical recording medium.   A predetermined range in which a β value representing a difference between the amplitude center value of the longest recording mark and the amplitude center value of the shortest recording mark acquired based on the RF signal of the reproduction signal that fluctuates according to the change in the laser output power is set in advance. 4. The phase change optical recording medium information according to claim 3, wherein the laser output power is controlled when it is determined whether or not the β value is within a predetermined range set in advance. Rewrite method.   Test writing was performed by changing the laser output power with a laser in the test writing area of the phase change optical recording medium, and the optimum recording power was obtained based on the RF signal characteristics of the reproduction signal of the test written area. 5. The phase change optical recording medium information rewrite according to claim 3, wherein the laser output power is controlled based on a comparison result between the β value of the area and the β value of the area where information recording is to be started. Method. The laser output power is controlled when the β value (β ₁ ) of the region where information recording is to start and the β value (β _OPC ) in the region immediately after the trial writing satisfy β ₁ > β _OPC. 6. The method of rewriting information on a phase change optical recording medium according to claim 4 or 5. When the condition of β ₁ > β _OPC is satisfied, when the recording power for recording on the phase change optical recording medium is P _w and the laser output power determined by trial writing is P _opc , 0.85 × 7. The phase change optical recording medium information rewriting method according to claim 6, wherein recording is performed with a recording power under a condition of P _opc ≦ P _w <P _opc . The ratio of the recording power (P _w ) for recording on the phase change optical recording medium to the erasing power (P _e ) for erasing is ε (= P _e / P _w ), and the above condition of β ₁ > β _OPC is satisfied. When ε is ε _opt and ε _def is ε _def when the above condition β ₁ > β _OPC is not satisfied, erasing is performed with an erasing power of 0.9 × ε _def ≦ ε _opt <ε _def. 7. The method of rewriting information on a phase change optical recording medium according to claim 6, wherein the method is performed.   9. When recording is performed on a phase change optical recording medium, the recording is performed at a maximum recording linear velocity that can be supported by the specifications of the phase change optical recording medium. 2. A method for rewriting information on a phase change optical recording medium according to 1. An optical unit that optically records, reproduces, and erases information by irradiating a phase change optical recording medium with laser light, and a laser that drives the laser light source that emits the laser light with a set laser output power A phase change optical recording medium information rewriting device comprising a drive unit and a setting control unit configured to set the laser output power,
A detection unit that detects change information of a recording material characteristic state in the phase change type optical recording medium, wherein the setting control unit receives the detection data from the detection unit and sets the laser output power at the time of recording or erasing to an appropriate range; A phase change optical recording medium information rewriting device, characterized in that it is set in the inside.   11. The phase change optical recording medium information rewriting device according to claim 10, wherein the detection unit detects a change in the recording material characteristic state based on the number of rewrites of the phase change optical recording medium.   11. The phase change optical recording medium according to claim 10, wherein the detection unit detects a change in the recording material characteristic state based on a change in an RF signal characteristic of a reproduction signal in the phase change optical recording medium. Information rewriting device.   The β value representing the difference between the amplitude center value of the longest recording mark and the amplitude center value of the shortest recording mark acquired in advance by the detection unit based on the RF signal of the reproduction signal that fluctuates according to the change in the laser output power It is determined whether the set value is within a predetermined range, and when it is determined that the β value is within a predetermined range, the setting control unit controls the laser output power. Item 13. The phase change optical recording medium information rewriting device according to Item 12.   An optimum recording power based on the RF signal characteristics of the reproduction signal of the trial-written area, comprising a trial-writing unit for performing trial-writing by changing the laser output power by a laser to the trial-writing area of the phase-change optical recording medium The setting control unit controls the laser output power based on a comparison result by the detection unit between the β value of the area where the acquisition is performed and the β value of the area where recording of information is to be started. 14. The phase change optical recording medium information rewriting device according to claim 12 or 13. The setting control unit controls the laser output power when the β value (β ₁ ) of the area where recording of information is to be started and the β value (β _OPC ) in the area immediately after the trial writing satisfy β ₁ > β _OPC. 15. The phase change type optical recording medium information rewriting device according to claim 13 or 14. When the condition of β ₁ > β _OPC is satisfied, when the recording power for recording on the phase change optical recording medium is P _w and the laser output power determined by trial writing is P _opc , 0.85 × 16. The phase change optical recording medium information rewriting device according to claim 15, wherein the setting control unit performs power control so that recording is performed with a recording power _satisfying a condition of P _opc ≦ P _w <P _opc . The ratio of the recording power (P _w ) for recording on the phase change optical recording medium to the erasing power (P _e ) for erasing is ε (= P _e / P _w ), and the above condition of β ₁ > β _OPC is satisfied. When ε is ε _opt and ε is ε _def when the condition β ₁ > β _OPC is not satisfied, the setting control unit satisfies the condition of 0.9 × ε _def ≦ ε _opt <ε _def 16. The phase change optical recording medium information rewriting device according to claim 15, wherein power control is performed so that erasing is performed with erasing power.   18. When recording on a phase change optical recording medium, the recording is performed at a maximum recording linear velocity that can be supported by the specifications of the phase change optical recording medium. 2. A phase change optical recording medium information rewriting device according to 1.

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