JP2015005323A - Recording device and recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording device and a recording method, capable of performing high density recording.SOLUTION: The recording device comprises: a signal generation unit 11 generating a write strategy signal on the basis of recording data; a laser light source unit 12 emitting a laser beam on the basis of the write strategy signal; and a recording unit 13 condensing a laser beam emitted from the laser light source unit 12 onto a write-once, read-many recording medium to form a recording mark. The signal generation unit 11 generates a write strategy signal with a two-step or three-step drive waveform on the basis of the recording data. The laser light source unit 12 combines laser beams having a first recording power and a second recording power stronger than the first recording power, and emits the combined laser beam when the write strategy signal has a two-step drive waveform, and combines the laser beams having the first recording power, the second recording power, and having a third recording power stronger than the first recording power and weaker than the second recording power, and emits the combined laser beam when the write strategy signal has a three-step drive waveform.

Description

  The present invention relates to a recording apparatus and a recording method for recording information on a write-once recording medium.

  Currently, as an information recording medium using light, an optical disc (Blu-ray Disc (Blu-ray)) that records information using a laser beam having a wavelength of about 405 nm and an objective lens having a numerical aperture (Numerical Aperture, NA) of 0.85 is used. ray Disc) (registered trademark) (hereinafter referred to as BD) has been standardized and put into practical use.

The BD includes a write-once BD-R and a rewritable BD-RE. As media having different laser wavelengths and NA, DVD-R, DVD-RW, DVD + RW, DVD-RAM, CD-R, CD-RW, etc. are standardized and put into practical use.
The data capacity of the BD format is 25 GB per recording layer on one side, or 33 GB by introducing a read technique with few errors by waveform equalization signal processing of a reproduction signal.

  Currently, increasing the NA of the condensing lens in the optical disk recording apparatus is being studied as a recording method for realizing a further large capacity and high transfer rate.

  By the way, as a technique for achieving an NA larger than 1, a recording / reproducing method (near field optical recording, NFR) reproduction using an evanescent wave, that is, light (near-field light) exponentially attenuated from the interface is used. Method).

  For example, in Patent Document 1, a near-field optical system is configured by combining an objective optical lens and a solid immersion lens (Solid Immersion Lens) (hereinafter referred to as SIL), and a near-field light is applied to an optical disc. An apparatus for recording and reproducing information by irradiation is disclosed.

  In addition, the optical disk is a phase change optical disk using a rewritable material such as GeSbTe, or a one-time writing (write once read many) using an organic dye material or an inorganic material such as BiGeO, TeOPd, or BiBO as a recording film. , WORM).

  Here, in the optical disk recording apparatus, when recording the laser beam from the optical head (optical pickup) with the objective lens and recording it on the optical disk, it is necessary to record the mark stably and reproduce it without error. A drive recording compensation (Write Strategy) technique is employed (see, for example, Patent Document 2). The optical disk recording apparatus not only uniformly irradiates laser light with WS, but also records the end of the mark after laser irradiation called a tear-drop shape due to heat accumulated in the recording film when recording a long mark. This prevents the phenomenon of mark enlargement.

  For example, the optical disk recording apparatus is mainly used for an optical disk (for example, BD-RE) using GeSbTe, as shown in FIG. 6 (a). The maximum recording power P11, bias power P12, and cooling power P13 are three. Marks are recorded by applying a multi-pulse type WS composed of two laser power values. In reproduction, a sufficient signal-to-noise ratio (S / N) is ensured, and the mark time timing shift (jitter) Accurate and stable recording and playback with less data errors.

  In addition, the optical disc apparatus is mainly used for an optical disc (for example, BD-R) using an inorganic material such as BiBO, as shown in FIG. 6B, with a maximum recording power P21, a buffer recording power P22, A so-called castle type WS composed of four laser power values of bias power P23 and cooling power P24 is applied, and recording and reproduction are performed stably without error of data as described above.

JP 2007-2931979 A JP 2009-217933 A

Here, consider near-field optical recording employing an SIL having an NA of 1 or more. Note that the NA of the objective lens standardized by BD is 0.85.
When a SIL of 1.7, whose NA is twice that of BD, is employed, the diameter of the beam spot is halved compared to BD, and the area of the recording beam spot focused to the diffraction limit is 1 / compared to BD. 4 Therefore, when the SIL with NA of 1.7 is employed, the thermal energy density is higher than that of the BD when irradiated with the same recording power as that of the BD.

In addition, it has been found that an optical disc using GeSbTe can stably record marks by employing a multi-pulse ternary WS.
By the way, when a multi-pulse type ternary WS is employed for an optical recording medium made of an inorganic material for WORM, the accumulated thermal energy is too low and it is difficult to form a sufficient recording mark. There is.

On the other hand, when a castle type quaternary WS is used for an optical recording medium made of an inorganic material for WORM, unlike a multi-pulse ternary WS, an intermediate power is required when forming a long recording mark. Therefore, there is an advantage that a sufficient recording mark can be formed and a sufficient S / N can be obtained even if the entire laser power is low.
However, the deviation (jitter) in the timing direction of the recording mark has a problem of becoming worse when the WS shape is complexly driven with four values.

  The present invention relates to a recording apparatus and a recording method capable of forming a recording mark on a recording film optical disc of an inorganic material for WORM by multi-pulse WS and performing high density recording while reducing jitter. One purpose is to provide.

  The recording apparatus according to claim 1 is a recording apparatus for recording information on a write-once recording medium having a recording film made of a predetermined inorganic recording material, and generates a write strategy signal based on the recording data. A signal generating unit, a laser light source unit that emits laser light based on the write strategy signal, and a laser beam emitted from the laser light source unit is condensed on the write-once recording medium to form a recording mark A recording unit, and the signal generation unit generates the write strategy signal with a two-stage driving waveform when the number of continuous high signals is n or less based on the recording data, When the number of High signals to be generated is greater than n, the write strategy signal is generated by a three-stage driving waveform, and the laser light source unit When the signal is a two-stage drive waveform, based on the drive waveform, a first recording power and a laser beam having a second recording power stronger than the first recording power are emitted in combination, and the write strategy signal is 3 In the case of a staged drive waveform, based on the drive waveform, the first recording power, the second recording power, and the third recording that is stronger than the first recording power and weaker than the second recording power. The power laser beam is combined and emitted.

  According to such a configuration, the recording apparatus employs a multi-pulse binary or ternary WS to form a recording mark on an optical film (for example, write-once Blu-ray) of an inorganic material recording film for WORM. Therefore, high-density recording can be performed while reducing jitter.

  In the recording apparatus according to claim 2, the recording unit includes a near-field light recording unit having a solid immersion lens that condenses the laser light emitted from the laser light source unit onto the write-once recording medium. May be.

  According to such a configuration, the recording apparatus employs a multi-pulse type binary or ternary WS for a recording film optical disc made of an inorganic material for WORM by using near-field light, thereby recording marks. Therefore, ultra-high density recording can be performed while reducing jitter.

  The recording apparatus according to claim 3, wherein the first recording power is a bias power, the second recording power is a maximum recording power, and the third recording power is a relaxed recording power. Good.

  According to such a configuration, the recording apparatus does not use a power lower than the bias power unlike the conventional apparatus and does not drive the WS shape in a complicated manner, so that high density recording can be performed while reducing jitter. .

  In the recording apparatus according to claim 4, the bias power may be 20% to 50% of the maximum recording power.

  According to this configuration, the recording apparatus can stably perform high-density recording while reducing jitter.

  In the recording apparatus according to claim 5, the relaxation recording power may be 85% to 98% of the maximum recording power.

  According to this configuration, the recording apparatus can stably perform high-density recording while reducing jitter.

  The recording method according to claim 6 is a recording method for recording information on a write-once recording medium having a recording film made of a predetermined inorganic recording material, and generates a write strategy signal based on the recording data. A signal generating step, a laser light emitting step for emitting laser light based on the write strategy signal, and a condensing step for condensing the laser light emitted by the laser light emitting step on the write-once recording medium And the signal generating step generates the write strategy signal with a two-stage driving waveform based on the recording data, when the number of continuous high signals is n or less, and the continuous high signal Is greater than n, the write strategy signal is generated by a three-stage drive waveform, and the laser beam emission step includes the write strategy When the signal is a two-stage drive waveform, based on the drive waveform, a first recording power and a laser beam having a second recording power stronger than the first recording power are emitted in combination, and the write strategy signal is 3 In the case of a staged drive waveform, based on the drive waveform, the first recording power, the second recording power, and the third recording that is stronger than the first recording power and weaker than the second recording power. In this configuration, power laser beams are combined and emitted.

  According to such a configuration, the recording method employs a multi-pulse type binary or ternary WS to form a recording mark on an optical recording medium made of an inorganic material for WORM, thereby reducing jitter. However, high density recording can be performed.

  According to the present invention, a recording mark is formed by multi-pulse WS on an optical disc of an inorganic material recording film for WORM, and high-density recording can be performed while reducing jitter.

It is sectional drawing of a write-once type recording medium. It is a block diagram which shows the structure of a recording device. FIG. 5 is a diagram for explaining a waveform of a WS signal and a recording mark formed on a recording track of a write-once recording medium. It is a block diagram which shows the structure of a signal generation part. It is a figure with which it uses for description about the process at the time of converting recording data into a WS signal. It is a figure where it uses for description about the waveform of the WS signal produced | generated by the conventional apparatus, and the recording mark formed in a recording track.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
The recording device 1 records information on a write-once recording medium 2 having a recording film made of a predetermined inorganic recording material. The predetermined inorganic recording material is, for example, BiBGeO. In addition, other than BiBGeO, for example, BiGeO, BiBO, etc. may be used.
Further, the write-once recording medium 2 having a recording film made of an inorganic recording material is synonymous with an optical disk of an inorganic material recording film for WORM (write once read many).

A cross section of the write-once recording medium 2 is shown in FIG. The write-once recording medium 2 includes a reflective layer (for example, Ag-alloy) 22, an intermediate layer (for example, SiN) 23, and a lower dielectric layer (for example, for example) on a substrate (for example, polycarbonate) 21 on which track grooves are formed. A ZnS—SiO ₂ ) 24, a recording layer (eg, BiBGeO) 25, an upper dielectric layer (eg, ZnS—SiO ₂ ) 26, and a surface layer (eg, SiN) 27 are formed. In the present embodiment, the write-once recording medium 2 has a diameter of 120 mm and a track pitch of 160 nm.
The recording mark may be formed only on the land side, only on the groove side, or on both the land side and the groove side.

Further, as shown in FIG. 2, the recording apparatus 1 includes a signal generation unit 11, a laser light source unit 12, and a recording unit 13.
The signal generator 11 generates a write strategy signal (hereinafter referred to as a WS signal) based on the recording data.
The laser light source unit 12 emits laser light based on the WS signal.
The recording unit 13 condenses the laser light emitted from the laser light source unit 12 on a write-once recording medium to form a recording mark.

  When the number of continuous high signals is n or less based on the recording data, the signal generation unit 11 generates a WS signal with a two-stage drive waveform, and the number of continuous high signals is greater than n. If there are many, a WS signal is generated with a three-stage drive waveform.

  Here, the conversion of the signal recorded and modulated to the 1-7pp code employed in the BD will be described. The signal generator 11 converts the recording mark into a combination of recording marks and spaces from 2T to 9T according to the clock length T (nsec) of the recording data to be input.

The recording data input to the signal generator 11 is composed of a high signal (hereinafter expressed as “1”) and a low signal (hereinafter expressed as “0”).
For example, when the recording data is “... 111...”, The signal generation unit 11 converts the recording data into a combination of 3T recording marks and spaces.

  In addition, when the number of continuous high signals is n (for example, 4) or less, that is, in the case of 2T to 4T, the signal generation unit 11 generates WS signals with two-stage drive waveforms and continues. When the number of high signals is larger than n (for example, 4), that is, in the case of 5T to 9T, the WS signal is generated by three stages of drive waveforms.

  When the WS light signal has a two-stage drive waveform, the laser light source unit 12 emits a combination of the first recording power and the laser light having the second recording power stronger than the first recording power based on the driving waveform, When the WS signal has a three-stage drive waveform, based on the drive waveform, the first recording power, the second recording power, and the third recording power that is stronger than the first recording power and weaker than the second recording power. A combination of power laser beams is emitted.

According to such a configuration, the recording apparatus 1 forms a recording mark by adopting a multi-pulse type binary or ternary WS for a write-once recording medium 2 having a recording film made of an inorganic recording material. Therefore, high-density recording can be performed while reducing jitter.
The recording unit 13 may be configured by a near-field light recording unit having a solid immersion lens that condenses laser light emitted from the laser light source unit 12 on a write-once recording medium. According to such a configuration, the recording apparatus 1 uses the near-field light to form the recording mark on the write-once recording medium 2 by using multipulse binary or ternary WS. Ultra-high density recording can be performed while reducing jitter.

The first recording power is, for example, the bias power P1. The second recording power is, for example, the maximum recording power P2. The third recording power is, for example, the relaxed recording power P3.
The bias power P1 is, for example, 20% to 50% of the maximum recording power P2.
The relaxed recording power P3 is, for example, 85% to 98% of the maximum recording power P2.

  Here, FIG. 3 shows the waveform of the WS signal according to the present embodiment. FIG. 3 shows an example in which 2T and 5T recording data “0110011111” is converted into a WS signal. In this embodiment, the bias power P1 is set to 1.10 mW, the maximum recording power P2 is set to 2.60 mW, and the relaxed recording power P3 is set to 2.55 mW. Not limited. Further, the relaxed recording power P3 in the WS signal may be a flat shape as shown in FIG. 3A or a comb shape as shown in FIG.

  As shown in FIG. 3, the signal generator 11 converts 2T recording data into a WS signal composed of bias power P1 and maximum recording power P2. Further, the signal generator 11 converts 5T recording data into a WS signal composed of bias power P1, maximum recording power P2, and relaxed recording power P3.

  According to such a configuration, the recording apparatus 1 does not use power lower than the bias power P1 unlike the conventional apparatus, and does not drive the shape of the WS signal in a complicated manner. Therefore, the write-once recording medium 2 is reduced while reducing jitter. High density recording can be performed.

Next, specific processing when the recording apparatus 1 converts 5T recording data into a WS signal will be described.
As shown in FIG. 4, the signal generator 11 includes a clock signal generator 111, a Wr1 signal generator 112, a Wr2 signal generator 113, a Wr3 signal generator 114, an INHABIT pulse generator 115, and a WS signal. And a generation unit 116.

The clock signal generation unit 111 generates a clock signal that serves as a time reference for recording data.
The Wr1 signal generation unit 112 generates a Wr1 signal for outputting the maximum recording power P2 based on the recording data.
The Wr2 signal generation unit 113 generates a Wr2 signal for outputting the bias power P1 based on the recording data. In the example illustrated in FIG. 5, the Wr2 signal indicates Low and Active.
The Wr3 signal generation unit 114 generates a Wr3 signal in order to output the buffer recording power P3 based on the recording data.
The INHIBIT pulse generator 115 generates an INHABIT signal that specifies an active time.

The WS signal generation unit 116 combines the Wr1 signal, the Wr2 signal, and the Wr3 signal based on the INHABIT signal, and generates a WS signal.
The WS signal generation unit 116 outputs the WS signal to the laser light source unit 12 based on the clock signal.
Based on the WS signal, the laser light source unit 12 emits laser light composed of the bias power P1, the maximum recording power P2, and the buffered recording power P3 to the recording unit 13.

  Next, experimental results will be described. In the experiment, a recording mark was formed on the optical disk by the recording apparatus according to the present example equipped with SIL, and a jitter value, which is a deviation from the clock timing of the recording mark, was evaluated. The recording conditions are as follows: an optical lens medium having a track pitch of 160 nm with a diameter of 120 mm and rotating at a linear velocity of 2.46 m / s, in which a laser light source having a wavelength of 405 nm and an SIL having an NA of 1.84 are mounted on the head of the recording apparatus. Gap servo operation that keeps the distance (gap) between the SIL and the disk surface close to an interval of 18 nm and a track (groove) of the above width for a recording medium as shown in FIG. Tracking servo operation was performed, and recording / reproduction was performed with a recording capacity equivalent to 100 GB and a transfer rate of 36 Mbps under the condition of the shortest mark length of 74.5 nm by 1-7PP recording modulation limited to run length (1, 7). . The total jitter value of the reproduced signal was measured and evaluated using a time interval analyzer (manufactured by Yokogawa Meter & Instruments Co., Ltd.). The bit error rates were also compared.

  A recording mark (hereinafter referred to as a conventional recording mark) based on a castle type 4-value WS signal (for example, a WS signal as shown in FIG. 6B) by the conventional apparatus, and a ternary WS by the recording apparatus 1 according to the present embodiment. When compared with a recording mark based on a signal (hereinafter referred to as a recording mark in this embodiment), the jitter of the conventional recording mark is low when the recording power is 2.60 mW, 2.55 mW, 1.00 mW and 0.05 mW. The value is 17.8 percent, and the jitter value of the recording mark in the case of the recording power (2.60 mW, 2.55 mW, 1.00 mW) of this embodiment is 16.8 percent. Thus, the jitter value of the recording mark of this example is improved compared to the conventional recording mark.

  In the case of high recording power (4.10 mW, 4.00 mW, 1.10 mW and 0.10 mW), the jitter value of the conventional recording mark is 14.6%, and the recording power (4 .10 mW, 4.00 mW, 1.10 mW), the jitter of the recording mark is 14.2%. In this way, even at high recording power, the recording mark of this example has an improved jitter value compared to the conventional recording mark.

Further, the bit error rate of the conventional recording mark is 1 × 10 ⁻³ , whereas the bit error rate of the recording mark of the present embodiment is 8 × 10 ⁻⁴ . Therefore, the recording apparatus 1 according to the present embodiment can form recording marks on the write-once recording medium 2 more stably than the conventional apparatus. Note that the recording apparatus 1 can further reduce the jitter value by precisely optimizing the overall timing and power of the WS signal.

  In the present embodiment, the configuration and operation of the recording apparatus have been mainly described. However, the present invention is not limited thereto, and each component is provided, and a multi-pulse WS is provided for an optical recording medium recording film made of an inorganic material for WORM. May be configured as a method and a program for forming a recording mark and performing high-density recording while reducing jitter.

  Furthermore, the program for realizing the function of the recording apparatus may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by a computer system and executed.

  The “computer system” here includes an OS and hardware such as peripheral devices. The “computer-readable recording medium” refers to a storage device such as a portable medium such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and a hard disk built in the computer system.

  Furthermore, “computer-readable recording medium” means that a program is dynamically held for a short time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line. It is also possible to include one that holds a program for a certain time, such as a volatile memory inside a computer system that becomes a server or client in that case. Further, the program may be for realizing a part of the above-described functions, and may be capable of realizing the above-described functions in combination with a program already recorded in the computer system. .

DESCRIPTION OF SYMBOLS 1 Recording device 2 Write-once recording medium 11 Signal generation part 12 Laser light source part 13 Recording part 111 Clock signal generation part 112 Wr1 signal generation part 113 Wr2 signal generation part 114 Wr3 signal generation part 115 INHABIT pulse generation part 116 WS signal generation part

Claims (6)

In a recording apparatus for recording information on a write-once recording medium having a recording film composed of a predetermined inorganic recording material,
A signal generator for generating a write strategy signal based on the recording data;
A laser light source unit for emitting laser light based on the light strategy signal;
A recording unit that condenses the laser light emitted from the laser light source unit on the write-once recording medium to form a recording mark, and
When the number of continuous high signals is n or less based on the recording data, the signal generation unit generates the write strategy signal with a two-stage drive waveform, and the number of continuous high signals is n If there are more than the number, the write strategy signal is generated by a three-stage drive waveform,
When the write strategy signal has a two-stage driving waveform, the laser light source unit combines a first recording power and a laser beam having a second recording power stronger than the first recording power based on the driving waveform. If the write strategy signal has a three-stage driving waveform, the first recording power, the second recording power, and the first recording power are stronger than the first recording power based on the driving waveform. A recording apparatus that emits a combination of laser beams having a third recording power that is weaker than two recording powers.   The recording apparatus according to claim 1, wherein the recording unit includes a near-field light recording unit having a solid immersion lens that condenses laser light emitted from the laser light source unit onto the write-once recording medium. The first recording power is a bias power;
The second recording power is a maximum recording power,
The recording apparatus according to claim 1, wherein the third recording power is a relaxed recording power.   The recording apparatus according to claim 3, wherein the bias power is 20% to 50% of the maximum recording power.   4. The recording apparatus according to claim 3, wherein the relaxed recording power is 85% to 98% of the maximum recording power. In a recording method for recording information on a write-once recording medium having a recording film composed of a predetermined inorganic recording material,
A signal generation step for generating a write strategy signal based on the recorded data;
A laser beam emitting step of emitting a laser beam based on the write strategy signal;
A condensing step of condensing the laser light emitted by the laser light emitting step on the write-once recording medium,
In the signal generation step, when the number of continuous high signals is n or less based on the recording data, the write strategy signal is generated by a two-stage drive waveform, and the number of continuous high signals is n If there are more than the number, the write strategy signal is generated by a three-stage drive waveform,
When the write strategy signal has a two-stage driving waveform, the laser beam emitting step combines a first recording power and a laser beam having a second recording power stronger than the first recording power based on the driving waveform. And when the write strategy signal has a three-stage drive waveform, based on the drive waveform, the first recording power, the second recording power, stronger than the first recording power and the A recording method of emitting a combination of laser beams having a third recording power that is weaker than the second recording power.

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