JPH0765378A - Optical recording method, optical recording medium and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] The optimum power detected by the recording device in the optical recording method in which recording is performed by setting the light irradiation intensity during recording by performing test recording in a specific test recording area of the optical recording medium. (EN) Provided is an optical recording method which has a wide power margin with respect to (Po) and does not cause an error in various recording devices. [Structure] The recording linear velocity of the test recording area is set to be different from the recording linear velocity of the data recording area. In this case, it is preferable to use an optical recording medium in which information of recording linear velocity is pre-pitted in the information pits and / or the guide grooves of the test recording area and the data recording area.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical recording method, an optical recording medium and a manufacturing method thereof.

[0002]

2. Description of the Related Art In recent years, the development of a write-once CD (compact disc) has become active. This is a conventional CD
Unlike the above, the user can record information, and since the signal after recording satisfies the standard of the conventional CD, it can be reproduced by a commercially available CD player.
As one of methods for realizing such a medium, JP-A-2-42652 proposes to spin coat a substrate with a dye to provide a light absorbing layer and a metal reflecting layer behind the light absorbing layer. . Further Japanese Patent Laid-Open No. 2-
It is reported in Japanese Patent Laid-Open No. 132656 that the signal after recording can satisfy the CD standard and a write-once CD can be realized by appropriately selecting the complex refractive index and the film thickness of the light absorption layer.

Incidentally, the write-once CD is required to be recordable by various commercially available CD writers as well as being reproducible by a commercially available CD player after recording. For that purpose, it is necessary to satisfy the standard of recording characteristics (Orange Book standard). That is, in this Orange Book standard, the recording power margin of the write-once CD is Po ± 15.
%, And a write-once CD recorded with a recording power within this range must be playable by a commercially available CD player. Here, Po is the optimum recording power obtained by performing power calibration in the test recording area (PCA) of the write-once CD by the CD writer,
It is a value unique to each write-once CD.

[0004]

However, the conventional write-once type CD has a large dependence on the wavelength of the recording light, and therefore, various CDs cannot be used.
Considering the variation of the laser light wavelength of the lighter, P
o It was difficult to satisfy the power margin of ± 15%. Also, depending on the combination of the CD writer and the write-once CD, as shown in FIG. 1, Po calculated by the CD writer may deviate from the Cl error window.
There was a problem that a recording error occurred. The reason why Po is deviated in this way is as follows.
That is, in a CD writer, Po is obtained from the asymmetry (β value) of the I ₃ and I ₁₁ signal waveforms, but since noise jitter also has recording power dependency, Po obtained from the asymmetry does not always coincide with the error window center. Because there is no.

Also, since the recording linear velocity of the write-once CD is as slow as about 1.3 m / s, the signal waveform of the long recording pit (I ₁₁ ) is easily distorted. In the case of such a distorted signal waveform, Po is detected to be larger than in the case of a normal waveform. This is Po for a distorted signal waveform as shown in FIG.
This is because at the time of detection, Po is obtained by measuring the peak point of the waveform distortion that is different from the substantial level.

There has been a problem that Po deviates from the error window even in a medium other than the write-once CD.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and has a wide power margin with respect to the optimum power (Po) detected by the recording apparatus.
An object of the present invention is to provide an optical recording method, an optical recording medium, and a method for manufacturing the same, which are free from errors in various recording devices.

[0008]

In order to achieve the above object, according to the present invention, by performing test recording in a specific test recording area of an optical recording medium, the light irradiation intensity during recording is set and recording is performed. In the optical recording method to be performed, there is provided an optical recording method characterized in that a recording linear velocity in a test recording area is different from a recording linear velocity in a data recording area. Also,
According to the present invention, there is a specific test recording area for setting the light irradiation intensity at the time of recording, and information of recording linear velocity is prerecorded in the information pits and / or the guide grooves of the test recording area and the data recording area. An optical recording medium is provided. Further, according to the present invention, in the method for manufacturing an optical recording medium, a step of providing a photoresist layer on a master and exposing and developing a laser beam to form an uneven pattern of information pits and / or guide grooves A step of forming a conductive layer on the concavo-convex pattern and electroforming nickel, a step of peeling nickel from the master to produce a stamper for an optical recording medium, and using the stamper to form information pits and / or Alternatively, the method includes a step of forming a substrate having an uneven pattern of guide grooves and a step of forming a recording layer on the substrate, and the recording linear velocity is applied to the uneven pattern of the test recording area and the data recording area during the laser light exposure. There is provided a method for manufacturing an optical recording medium, which is characterized by pre-recording the information of 1. Further, according to the present invention, in the above, the information of the recording linear velocity is pre-recorded by changing the exposure linear velocity in the test recording area and the data recording area during laser light exposure. A manufacturing method is provided. Further, according to the present invention, in the above, in the step of forming the recording layer, the dye is the main component on the substrate having the information pits and / or the guide grooves formed on the surface thereof, directly or through another layer. There is provided a method for producing an optical recording medium, which comprises providing a light absorbing layer by a coating means, providing a light reflecting layer directly or via another layer, and further providing a protective layer thereon.

The present invention will be described in detail below. In the conventional write-once type CD, the test recording area (PCA) and the data recording area have the same recording characteristics. Therefore, when recording is performed using a medium for which the method of obtaining Po by asymmetry described above is not suitable, an error occurs. It was in a state where it was likely to occur. Therefore, in the present invention, Po is controlled by changing the recording linear velocities of the test recording area and the data recording area for which Po is to be determined. In the test recording area (PCA), Po is found at the center of the error window of the data recording area. The above-mentioned problems are solved by setting a high recording linear velocity. That is, in the present invention, the test recording area is the CD
Since it is not played by the player, the linear velocity is emphasized in the detection of Po.

In the recording method of the present invention, the test recording area and the data recording area are recorded at different linear velocities. In this case, the optical recording in which the recording linear velocity information is pre-recorded in the test recording area and the data recording area. A medium can be used. Here, as a method of pre-recording the information of the recording linear velocity, there are a method of pre-recording in the information pit and a method of pre-recording in the guide groove. Either method can be adopted, but a general CD writer does not. It is not compatible with media with ROM pits, and since the linear velocity is detected by the wobble signal frequency of the guide groove, the guide groove is formed by changing the wobble signal frequency with respect to the linear velocity. Is preferred. Specifically, the wobble signal frequency with respect to the linear velocity in the test recording area can be set to a higher frequency than that in the data recording area to slow the linear velocity, and to lower the frequency to increase the linear velocity. The recording sensitivity can be improved and Po can be reduced when the linear velocity is low, and the recording sensitivity can be reduced and Po can be increased when the linear velocity is high.

The optical recording medium used in the present invention is basically a recording layer on a substrate in which information of recording linear velocity is prerecorded in the information pits and / or guide grooves of the test recording area and the data area as described above. However, as a preferable layer configuration example, a light absorbing layer containing a dye as a main component is provided on the substrate directly or through another layer, and a light absorbing layer is provided thereon directly or through another layer. The thing which provided the reflective layer and further provided the protective layer on it can be mentioned. The substrate material that can be used in the present invention can be arbitrarily selected from conventional substrate materials for optical recording media. Examples thereof include resin materials such as polycarbonate (PC), polymethylmethacrylate (PMMA), polyvinyl chloride, amorphous polyolefin, epoxy and polyester, and glass. A particularly preferable material is a polycarbonate resin which is excellent in mass productivity by injection molding and has good wettability of a coating solution, fixability of a dye material, and film forming property. Further, as the light absorbing layer material usable in the present invention, cyanine dye, phthalocyanine dye, azurenium dye, squarylium dye, polymethine dye, pyrylium dye, thiopyrylium dye, indoaniline dye, naphthoquinone dye, anthraquinone dye, triallylmethane dye , Aminium dyes, diimonium dyes, metal complex dyes, and the like, and mixtures thereof, but are not limited thereto. Further, as the light reflecting layer material usable in the present invention,
Gold, silver, aluminum or alloys thereof can be mentioned. The protective layer material that can be used in the present invention is preferably an ultraviolet curable resin, but is not limited to this.

The optical recording medium according to the present invention can be manufactured by a method including the steps described below. That is, (1) a step of forming a photoresist groove on the master, forming a guide groove uneven pattern by laser light exposure and development, (2) a step of forming a conductive layer on the uneven pattern and nickel electroforming, (3) a step of peeling nickel from the master to produce a stamper for an optical recording medium, (4) a step of molding a substrate having a guide groove uneven pattern on the surface using the stamper, (5) a recording layer on the substrate And a method of prerecording recording linear density information on the concavo-convex pattern of the test recording area and the data recording area during the laser light exposure. This pre-recording can be performed, for example, by changing the exposure linear velocity in the test recording area and the data recording area during laser light exposure. The linear velocity during this exposure corresponds to the recording linear velocity in the test recording area and the data recording area.

Further, according to the present invention, a light absorbing layer containing a dye as a main component is provided on a substrate having information pits and / or guide grooves formed on the surface thereof, and directly or through another layer. In the production of an optical recording medium having a structure in which a light-reflecting layer is provided directly on or through another layer, and a protective layer is further provided thereon,
A medium can be prepared by forming the light absorption layer by a coating method.

[0014]

EXAMPLES Next, examples of the present invention will be described, but the present invention is not limited to these examples.

Example 1 A photoresist was applied to the surface of a glass substrate, laser exposure was performed in the pattern shown in FIG.
Form a wobble guide groove uneven pattern of 5 KHz,
After forming a conductive film by the sputtering method, Ni electroforming was performed to form a stamper on one surface of the glass substrate. This stamper is peeled from the glass substrate, the residual photoresist is removed, and then φ is formed by injection molding using this stamper.
A disk substrate having a guide groove concavo-convex pattern on the surface of a polycarbonate disc of 120 mm was prepared. The guide groove depth of this substrate was about 500Å.

On the other hand, 1.5 wt% of the cyanine dye of the following formula (1) was dissolved in a solvent prepared by adding 5 wt% of ethylene glycol monomethyl ether acetate to 2,2,3,3-tetrafluoropropanol to prepare a coating solution, A light absorption layer was provided by spin coating on the surface of the substrate.
The thickness of the light absorption layer was about 1300Å. Next, Au was formed on the light absorption layer by Au sputtering to a thickness of about 800 Å to form a reflection layer, and a protective layer made of an ultraviolet curable resin was further formed thereon to a thickness of about 5 μm to form a reflective layer of the present invention. The media.

[Chemical 1]

A wavelength of 785 nm was used for the medium obtained above,
N. A. Recording and reproduction were carried out under the conditions of 0.5 and wobble signal rotation control, and Po of the PCA area and Cl error window of the data recording area were obtained. The result is shown in FIG. As is clear from FIG. 4, Po (Po1 in FIG. 4) was almost the center value of the Cl error window.

Example 2 In Example 1, the exposure linear velocity of PCA was 1.35 m / s.
And, except that the mixture of the dyes of the formulas (1) and (2) is used on the substrate having the guide groove depth of about 1400Å, and the light absorbing layer is provided under the condition that ethylene glycol monomethyl ether acetate is not added, To produce the media of the present invention. The Po in the PCA area of this medium was approximately the center value of the Cl error window in the data recording area (Po1 in FIG. 5).

[Chemical 2]

Comparative Example 1 In Example 1, except that a substrate having a guide groove concavo-convex pattern in which the wobble signal frequencies of the PCA area and the data recording area were the same with respect to the linear velocity (1.4 m / s) was used. When a comparative medium was prepared in the same manner and the same measurement was performed, Po was deviated from the center of the Cl error window (Po2 in FIG. 4).

Comparative Example 2 In Example 2, except that a substrate having a guide groove uneven pattern in which the wobble signal frequencies of the PCA area and the data recording area were the same with respect to the linear velocity (1.4 m / s) was used. When a comparative medium was similarly prepared and the same measurement was performed, Po was deviated from the center of the Cl error window (Po2 in FIG. 5).

As is clear from the above results, according to the present invention, a wide power margin can be obtained with respect to Po.

[0022]

According to the present invention, an optical recording method and an optical recording medium which have a wide power margin with respect to the optimum recording power (Po) detected by a recording device and which are free from errors in various recording devices. And a manufacturing method thereof.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between β value, jitter, Cl error and recording power.

FIG. 2 is a diagram showing AC signal waveforms with and without waveform distortion.

FIG. 3 is an explanatory diagram of a laser exposure pattern.

FIG. 4 is a diagram showing measurement results of Po and Cl error windows of Example 1 and Comparative Example 1.

5 is a diagram showing measurement results of Po and Cl error windows of Example 2 and Comparative Example 2. FIG.

Claims (5)

[Claims] 1. An optical recording method for performing recording by setting a light irradiation intensity at the time of recording by performing test recording in a specific test recording area of an optical recording medium, the recording linear velocity of the test recording area being a data recording area. The optical recording method is characterized in that it is different from the recording linear velocity of. 2. A specific test recording area for setting a light irradiation intensity at the time of recording, and recording linear velocity information is prerecorded in information pits and / or guide grooves of the test recording area and the data recording area. An optical recording medium characterized by being provided. 3. The method for manufacturing an optical recording medium according to claim 2, wherein a photoresist layer is provided on a master, and laser light exposure and development are performed to form an uneven pattern of information pits and / or guide grooves. A step of forming a conductive layer on the concavo-convex pattern and electroforming nickel, a step of peeling nickel from the master to produce a stamper for an optical recording medium, and using the stamper to form information pits and / or Alternatively, the method includes a step of forming a substrate having an uneven pattern of guide grooves and a step of forming a recording layer on the substrate, and the recording linear velocity is applied to the uneven pattern of the test recording area and the data recording area during the laser light exposure. A method for manufacturing an optical recording medium, characterized by pre-recording the information of 1. 4. The optical recording medium according to claim 3, wherein the recording linear velocity information is pre-recorded by changing the exposure linear velocity between the test recording area and the data recording area during laser light exposure. Production method. 5. The step of forming the recording layer comprises coating a substrate having an information pit and / or a guide groove formed on its surface with a light absorbing layer containing a dye as a main component directly or through another layer. 5. The method for producing an optical recording medium according to claim 3, further comprising: providing a light reflection layer directly on or via another layer, and further providing a protective layer thereon.