JP2003059044A - Recording method for optical information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording method for an optical recording information medium which can suppress the mean recording output of a laser low even in high-speed recording. SOLUTION: The recording method for the optical information recording medium which records and reproduces information by using laser light is characterized by that projection parts are provided at respective rise parts of a recording waveform in pulse-train format. Or the recording method is characterized by that projection parts are provided at respective rise parts of the recording waveform in pulse-train format and recessed parts are provided at respective fall parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording method for an optical information recording medium capable of recording and reproducing information using laser light.

[0002]

2. Description of the Related Art In recent years, optical information recording media have been diversified, and read-only CD (Compact Disk) -RO.
M, DVD (Digital Versatile D
isk) -ROM; write-once CD-R (Recorda)
ble), DVD-RAM; MO of rewritable magneto-optical medium; CD-RW (R as phase change type disc
Ewritable), DVD-RAM, DVD-RW
Etc.

Along with the speeding up of digital signal processing, there is an increasing demand for speeding up recording and reproduction of information recording devices.
In order to meet this demand, it is important to increase the relative speed between the energy beam (laser) and the information recording medium.

By increasing the relative speed of the energy beam and the information recording medium, more information can be recorded / reproduced within a unit time, so that the data transfer rate of the information recording / reproducing apparatus can be improved.

In the conventional DVD-R, the waveform of the laser that actually emits light with respect to the data to be recorded is recorded in the form of a pulse train as shown in FIG. T in FIG.
Is the cycle of the system clock, Po is the recording power level,
Pb indicates the bottom power level. FIG. 5A shows the data to be recorded, and the portion corresponding to the width of 8T corresponds to one pit. FIG. 5B shows a signal for actually causing the laser to emit light, and there is a long-time pulse at the beginning, and thereafter, the time during which the pulse is turned off within 1T and o.
n times are repeated and each signal is recorded on the disc. It should be noted that the drawing is created in consideration of easiness of thinking, and in reality, a pit is formed from a place where light is emitted, so that FIG. 5B shifts backward from FIG. 5A. It will be.

The recording speed up to now when recording as described above was 3.49 m / s, and there was a margin in the output of the recording laser, but when the recording speed becomes double or more high speed recording, The output required for recording is proportional to the route of the recording speed, so the output of the recording laser gradually becomes insufficient. For example, a laser output of maximum 12 mW at 1 × speed, maximum 17 mW at 2 × speed, and 24 mW at 4 × speed is required.

[0007]

From the above, the present invention is
An object of the present invention is to provide a recording method for an optical recording information medium capable of suppressing the average recording output of a laser even at high speed recording.

[0008]

The above objects can be solved by the present invention described below. That is, the present invention is <1> a recording method of an optical information recording medium for recording and reproducing information by using a laser beam, wherein a convex portion is provided at each rising portion of a pulse train type recording waveform. And a recording method for an optical information recording medium.

<2> A recording method of an optical information recording medium for recording and reproducing information using a laser beam, wherein a convex portion is provided at each rising portion of a pulse train type recording waveform, and each falling portion is provided. A recording method for an optical information recording medium, characterized in that a concave portion is provided in the optical recording medium.

<3> The recording power level Po ′ when the convex portion is provided is 1.05 to 1.2 times the recording power level Po when the convex portion is not provided, and The width is 10 to 50% with respect to the clock cycle T, which is the recording method of the optical information recording medium described in <1> or <2>.

<4> The recording power level Pb 'when the recess is provided is 30 to 80% of the bottom power level Pb when the recess is not provided, and the width of the recess is equal to the clock cycle T. 10% to 50% is the recording method of the optical information recording medium described in <2>.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION <Recording Method for First Optical Information Recording Medium> In the first recording method for an optical information recording medium of the present invention, a convex portion is provided at each rising portion of a pulse train type recording waveform. A method for recording information on an optical information recording medium.

FIG. 1 shows an example of a recording waveform when the recording method of the first optical information recording medium is applied. FIG. 1A shows the data to be recorded, and the portion corresponding to the width of 8T corresponds to one pit. As shown in FIG. 1B, a convex portion (overshoot portion) is provided at each rising portion of the recording waveform (pulse waveform). By providing such a convex portion in a certain range, it is possible to reduce the average recording power by about 10% at the maximum, and it is possible to obtain the same asymmetry with a recording power smaller than the conventional one. It is considered that this is because the convex portion facilitates the formation of the head portion of the pit, thereby reducing the amount of wasteful energy due to heat storage.

The recording power level Po 'when the convex portion is provided in FIG. 1B is preferably 1.05 to 1.2 times the recording power level Po when the convex portion is not provided. . If it is less than 1.05 times, the effect of reducing the average recording power is small, and if it exceeds 1.2 times, the jitter may be deteriorated. The recording power level Po
Is 6.0 to 12.0 mW.

Further, the width of the convex portion is preferably 10 to 50%, more preferably 10 to 30% with respect to the clock cycle T. If it is less than 10%, the effect of reducing the average recording power is small, and if it exceeds 50%,
Jitter deterioration may occur.

If the recording power level Po ′ and the width when the above-mentioned convex portions are provided are within the above-mentioned preferable ranges, the values of the convex portions provided at the respective rising portions may be the same or different. Good.

In order to provide a convex portion as shown in FIG. 1 (b) at the rising portion of the recording waveform, as shown in FIG. 2, the convex portion is added to the conventional pulse waveform signal (FIG. 2 (a)). It suffices to superimpose the pulse waveform signals (FIG. 2B) that form By setting the width and height of the pulse waveform forming the convex portion within the preferable range, the pulse waveform signal shown in FIG. 1B can be finally obtained.

<Recording Method of Second Optical Information Recording Medium> In the second recording method of the optical information recording medium of the present invention, a convex portion is provided at each rising portion of the recording waveform of the pulse train type, and a descending portion is provided. It is a method of recording information on an optical information recording medium by providing a concave portion.

FIG. 3 shows an example of a recording waveform when the recording method of the second optical information recording medium is applied. FIG. 3 (a) is shown in FIG.
Similar to (a), it indicates the data to be recorded, 8T
The portion corresponding to the width of 1 corresponds to one pit. Figure 3
As shown in (b), a concave portion (undershoot portion) is provided in the descending portion of the recording waveform. By providing such a convex portion and a concave portion in a certain range, it is possible to reduce the average recording power at the maximum by about 10% as in the recording method of the first optical information recording medium. Moreover, the same asymmetry can be obtained with a recording power smaller than that of the conventional one. This is because the convex portion facilitates the formation of the pit head portion, and the concave portion makes the shape of the rear end portion of the pit clean without being affected by heat storage, so that the amount of energy wasted up to now can be reduced. Is considered to be. The concave portion is provided in 1T. Further, the bottom power level Pb is 0.5 to 1.
It is 0 mW.

The recording power level Po 'when the convex portion of FIG. 3 (b) is provided is the same as the recording method of the first optical information recording medium. The recording power level Pb ′ when the recess is provided in FIG. 3B is preferably 30 to 100% of the bottom power level Pb when the recess is not provided, and is preferably 30 to 80%. More preferable. If it is less than 30%, the recording power may be insufficient and the servo function may not operate normally.

The width of the recess is 0 to the clock cycle T.
It is preferably 50%, more preferably 10 to 30%. If it exceeds 50%, the jitter may be deteriorated. If the recording power level Pb ′ and the width when the recess is provided are within the above-described preferred range, the values of the recesses provided in the respective descending parts may be the same or different. The same applies to the convex portion.

To provide the convex portion and the concave portion as shown in FIG. 3 (b), as shown in FIG. 4, a pulse for forming the convex portion is added to the signal of the conventional pulse waveform (FIG. 4 (a)). The waveform signal (FIG. 2B) and the pulse waveform signal that forms the concave portion (FIG. 4B) may be overlapped. By setting the width and height of the pulse waveform that forms the convex portion and the concave portion within the preferable ranges, the pulse waveform signal shown in FIG. 3B can be finally obtained.

The recording methods for the first and second optical information recording media described above can be applied to both write-once and rewritable optical information recording media having a recording layer.

Examples of the write-once type recording medium include DVD-R having a known light reflection layer and recording layer between two substrates such as polycarbonate. Examples of the rewritable optical information recording medium include a DVD-RW having a recording layer that reversibly changes its phase between a crystal phase and an amorphous phase. Further, the recording method of the optical information recording medium of the present invention is not limited to DVD, but other recording medium (CD etc.)
Can also be applied to.

[0025]

EXAMPLES The present invention will be specifically described with reference to the following examples, but the present invention is not limited thereto.

(Example 1) -Fabrication of optical information recording medium (DVD-R) -Groove depth 150 nm, track pitch 740 nm, groove width 3
Injection-molded polycarbonate resin with 00 nm spiral groove (thickness 0.6 mm, diameter 120 mm,
Teijin Polycarbonate: Trade name Panlite AD55
03) Ag was sputtered on the grooved surface of the substrate by DC magnetron sputtering to 150 nm.
A reflective layer having a film thickness of was formed.

0.25 g of a dye represented by the following structural formula (1)
And 0.06 g of the dye represented by the following structural formula (2):
It was added to 30 g of 2,3,3-tetrafluoropropanol and subjected to ultrasonic irradiation for 1 hour to dissolve it, thereby preparing a dye coating solution.

[0028]

[Chemical 1] ... Structural formula (1)

[0029]

[Chemical 2] ... Structural formula (2)

The dye coating wave prepared above was spin-coated to give a groove thickness of 160 nm.
Coating was performed under the conditions of 23 ° C. and 50% RH to form a recording layer on the reflective layer. Then, it was stored at 60 ° C. and 30% RH for 2 hours, and a UV curing adhesive (SD64 manufactured by Dainippon Ink and Chemicals, Inc.)
0) was spin-coated at a rotation speed of 60 rpm to stop the rotation, the same injection-molded polycarbonate resin as described above was overlaid, spin-coated at a rotation speed of 4400 rpm again to spread the adhesive on the entire surface, and then applied to a UV irradiation lamp. Then, it was irradiated with ultraviolet rays and cured to prepare an optical information recording medium (DVD-R).

-Recording on optical information recording medium and its evaluation- The recording waveform shown in FIG. 3 was used for the DVD-R manufactured as described above by a DVD-R evaluation device (DDU1000, manufactured by Pulstec Industrial Co., Ltd.). Recording was carried out by using the recording method, and the recording power (optimum recording power) that minimized the jitter was obtained. The results are shown in FIGS. 6 and 7 and Tables 1 and 2. The recording was performed at a disk rotation speed of 3.49 m / s and a radius of 30 mm.
The recording power was changed to the position of. In addition, Pb, Pb′Po and Po ′ in FIG. 3 are 0.7 m, respectively.
W, 0.4 mW, 9.0 mW and 9.9 mW.
The width of the convex portion was 20% with respect to the clock cycle T, and the width of the concave portion was 20% of T.

(Comparative Example 1) A DVD-R manufactured in the same manner as in Example 1 was recorded in the same manner as in Example 1 except that the recording waveform shown in FIG. 5 was used, and the jitter was minimized. The recording power (optimum recording power) was obtained. The results are shown in FIGS. 6 and 7 and Tables 1 and 2. In addition, the conventional example in FIGS. 6 and 7 refers to Comparative Example 1.

[0033]

[Table 1]

[0034]

[Table 2]

From FIG. 6 and Table 1, it was found that in Example 1, the recording power was reduced by about 1 mW to obtain the same asymmetry as in Comparative Example 1. FIG. 7 and Table 2
As a result, it was found that in Example 1, there was almost no difference between the minimum value of jitter and the asymmetry in which the jitter was minimum, as compared with Comparative Example 1, but apparent recording sensitivity was improved.

[0036]

According to the recording method of the optical recording information medium of the present invention, the average recording output of the laser can be suppressed to a low level even at the time of high speed recording, without giving a great change to the characteristics of jitter and asymmetry.

[Brief description of drawings]

FIG. 1 is a waveform diagram showing an example of a recording waveform applied to a recording method of an optical information recording medium of the present invention.

FIG. 2 is an explanatory diagram illustrating a method of obtaining the recording waveform shown in FIG.

FIG. 3 is a waveform diagram showing another example of a recording waveform applied to the recording method of the optical information recording medium of the present invention.

FIG. 4 is an explanatory diagram illustrating a method of obtaining the recording waveform shown in FIG.

FIG. 5 is a waveform diagram showing an example of a recording waveform applied to a recording method of a conventional optical information recording medium.

FIG. 6 is a diagram showing a relationship between recording power and asymmetry.

FIG. 7 is a diagram showing a relationship between asymmetry and jitter.

[Explanation of symbols]

T: Clock cycle Recording power level Po, Po ', Pb' ... Pb ... bottom power level

Claims (2)

[Claims] 1. A recording method of an optical information recording medium for recording and reproducing information by using a laser beam, characterized in that a convex portion is provided at each rising portion of a pulse train type recording waveform. Recording method for optical information recording medium. 2. A recording method of an optical information recording medium for recording and reproducing information by using a laser beam, wherein a convex portion is provided at each rising portion of a pulse train type recording waveform and each recording portion is provided at each falling portion. A recording method for an optical information recording medium, characterized in that a concave portion is provided.