JP2002288838A - Optical storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical storage medium having pits consisting of a variety of signal modulations and asymmetry values. SOLUTION: The optical disk 1, in which an information recording layer 4 containing an organic dye is formed on a substrate 3 having a guide groove 2, includes a metal reflective film 5 under the information recording layer 4 and an overcoat layer 6 under the metal reflective film 5. The pits having different signal modulations and the asymmetry values are recorded in different storage regions on the information recording layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rewritable optical recording medium, such as an optical recording medium, which irradiates a light beam to cause a change in an information recording layer such as an organic dye to record and reproduce information. Memory related devices, especially rewritable compact discs (CD-R, CD-RW, MD, D
VD-R.RW) and the like.

[0002]

2. Description of the Related Art In recent years, write-once compact discs which can be written only once using an organic dye are provided with CD-Rs.
・ There are media such as CD-RW, MD, DVD-R, and RW. Hereinafter, a description will be given of a CD-R as a representative. Since the CD-R and the like are inexpensive and can be almost reproduced by a general CD-ROM player, the CD-R has widely penetrated the market. Organic dyes used for information recording layers such as CD-R include cyanine dyes, phthalocyanine dyes, and azo dyes.

[0003]

However, cyanine dyes are most popular because of their ease of design and low production cost, but have the drawback of being susceptible to light and heat.

[0004] As an example, when a CD-R for recording is used in an automobile where environmental conditions are severe, the CD-R may be rapidly deteriorated due to an increase in the temperature inside the automobile or exposure to sunlight. Therefore, the CD player on the car audio side needs to be adjusted so that the CD-R can be reproduced even if the CD-R has deteriorated to some extent.

In general, the signal intensity of a CD-R of a cyanine dye is lowered in a high-temperature environment because the signal contrast is lowered due to oxidative deterioration of a recording film as an information recording layer.

That is, when the recording film is oxidized and degraded due to a high temperature environment, the I3R (signal modulation degree) of the reproduction signal of the CD-R decreases, and the asymmetry value (or Symm) is obtained.
(hereinafter, also referred to as an asymmetry value).

On the other hand, in the light exposure environment, the oxidative deterioration proceeds as in the high temperature environment, but the recording pit becomes large because the function of the photoquenching agent mixed with the dye in the recording pit portion is reduced. For this reason, the pit signal intensity becomes too strong. That is, in a cyanine-based CD-R that has been oxidatively degraded under a light exposure environment, I3R tends to decrease and asymmetry tends to decrease.

Further, in a rewritable optical storage medium such as a CD-R, the reproduction signal intensity of a pit is small,
Some personal computers equipped with a D-ROM player or a CD-ROM player may not be able to play CD-Rs.

That is, it is necessary to extend the period during which data can be read even from an oxidatively degraded cyanine-based disc, or to determine the reproduction capability of a CD-R or the like in accordance with the signal read capability of a CD-ROM player of various manufacturers. Requires various data for pits to be recorded on a CD-R.

In particular, since the oxidative deterioration of a cyanine-based disk progresses rapidly after it occurs, it cannot be used as a test disk. Therefore, there is no disk that can simulate such a signal deterioration process stably. It is.

The present invention has been made in view of such a problem, and simulates the signal reproducing ability of a CD-R or the like due to the oxidative deterioration and the signal reproducing ability of a CD-ROM player, thereby improving the oxidative deterioration. Test optical storage used to expand the extent to which data can be reproduced even if the data is reproduced, or to manufacture a CD-R or the like capable of reproducing data adapted to CD-ROM players having different reproduction capabilities for each manufacturer. The purpose is to provide a medium.

[0012]

Means for Solving the Problems As a result of intensive studies on the improvement of an optical recording medium, the present inventors have found an optical recording medium meeting the above-mentioned object and a method of manufacturing the optical recording medium.

That is, an optical storage medium according to the invention of claim 1 of the present application is a rewritable optical storage medium having an information recording layer containing a recordable organic dye and a metal reflective film. In addition, a plurality of types of test signals having different asymmetry values and modulation degrees are recorded so as to correspond to the data reproducing capability of the reproducing means of the optical storage medium.

An optical storage medium according to a second aspect of the present invention is the optical storage medium according to the first aspect, wherein the optical recording medium is a CD-R.

Further, an optical storage medium according to a third aspect of the present invention is the optical storage medium according to the second aspect, wherein the organic dye is a phthalocyanine dye.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a reference optical disc as a test optical storage medium according to an embodiment of the present invention will be described. FIG. 1 shows a test optical disc (CD-R) according to the embodiment.

In this optical disc 1, an information recording layer 4 containing an organic dye is formed on a substrate 3 having a guide groove 2, and a metal reflection film 5 is formed below the information recording layer 4, and an overcoat is formed below the metal reflection film 5. It has a layer 6. A print layer 7 is formed on the overcoat layer 6, and a hard coat layer 8 is formed on the mirror side of the substrate 3.

The material of the substrate 3 is usually glass, ceramics, or resin, but a resin substrate is preferable in terms of moldability and cost. Examples of the resin of the substrate 3 include:
Polycarbonate resin, acrylic resin, epoxy resin,
Polystyrene resin, acrylonitrile-styrene copolymer resin, polyethylene resin, polypropylene resin and the like can be mentioned, but polycarbonate resin and acrylic resin, which are excellent in moldability, optical properties and cost, are preferable. Further, the shape of the substrate may be a disk shape, a card shape or a sheet shape.

However, the optical disk 1 according to the embodiment
Is a one-time writing type (CD-R), the shape of the guide groove (groove) formed in the substrate 3 to be used can be arbitrarily determined. It is desirable to optimize according to the wavelength of the light for recording / reproducing and the beam system of the optical pickup. When a write-once compact disc such as a CD-R is taken as an example, it is desirable that the groove has a width of 300 to 800 nm and a depth of 100 to 300 nm.

The material of the organic dye of the information recording layer 4 is as follows.
The ones whose optical properties in the visible light range change in response to the change of the recording state can be used. Dyes, metal complex dyes such as Ni and Cr, naphthoquinones
Anthraquinone dyes, indophenylmethane dyes,
Examples include a trianylmethane dye, a triallylmethane dye, an aminium / diimmonium dye, and the like.

As the optical characteristics of the organic dye of the information recording layer 4, it is preferable to have an absorption band at 500 to 750 nm, and it is preferable to use a phthalocyanine dye in order to improve the reliability of the medium. An optional additive may be mixed into the information recording layer 4 in order to improve the optical properties, thermal properties and stability of the recording properties.

The thickness of the information recording layer 4 can be arbitrarily set so as to optimize the recording characteristics as an optical information medium, but is preferably 100 to 500 nm. The film formation of the information recording layer 4 is performed by a method suitable for the material, and there are a method of dissolving the material of the information recording layer in a solvent, coating and drying on the transparent substrate 3, and a vacuum evaporation method. The method by coating and drying is desirable from the viewpoint of the properties and the simplicity of film formation.

Examples of a film forming method of applying and drying using a solvent include a spin coating method and a dipping method, and it is preferable to use a spin coating method from the viewpoint of productivity in the process. <Writing of Reference Signal to Optical Disk> Next, writing of a signal to the optical disk 1 will be described. In this writing, the power is produced by oscillating the power in the plus direction or the minus direction for each area around the power of the laser beam for performing the optimum recording. It is preferable that the power is swung by 20% or more in both the plus direction and the minus direction, and the asymmetry value (Symme
(try value) plus or minus 20%, preferably 2
It is preferable that the deflection is 5% or more.

The electromagnetic waves used for recording and reproducing data on and from the optical disk 1 according to this embodiment include laser light, electron beams,
Various types such as X-rays, ultraviolet rays, visible rays, infrared rays, and microwaves can be employed. Among them, a small and compact semiconductor laser is most suitable. <Example> Hereinafter, a specific example of the present invention will be described.
In this example, a phthalocyanine dye 4 was applied to a substrate 3 made of polycarbonate having a groove of 0.65 μm in width and 160 nm in depth and made of 1.2 mm thick and having a light absorbance of 0.75 by a spin coating method and dried. A metal reflection film 5 was formed on the dye 4 by a sputtering device.
The metal reflective film 5 was adjusted to have a thickness of 110 nm for Ag. Next, an overcoat layer 6 formed by spin coating of an ultraviolet curable resin was formed to a thickness of about 5 μm, and an optical disc 1 (CD-R) was manufactured.

This optical disc 1 has an MP708 made by Ricoh
0A (trade name), a signal is written in the innermost portion at the optimum recording power, and the write beam light of the optical pickup is moved in the radial direction in the radial direction while increasing by 25% every predetermined time.
The recording power was increased every 5% until the data was written.

Next, after recording to plus 25%, the beam light is again written at the optimum recording power, and reaches 25% in the minus direction at predetermined time intervals while moving from the outer circumference to the inner circumference in the radial direction. The data was recorded with the power reduced every 5% until the recording was completed.

As a result, the optical disc 1 has pits that increase from the optimum recording power by 5% from the inner circumference to the outer circumference every predetermined time, and the recording power reaches (+) 25% at the outermost circumference. Is recorded. Next, when the recording power is 2
After reaching 5%, after returning to the optimum recording power, pits having a decreasing tendency of 5% are recorded in the (-) direction at predetermined time intervals, pits having a recording power of (-) 25% are recorded, and Asymmetry value for each (Symmetry value)
And pits having different I3Rs (signal modulation degrees) are recorded.

A test for displaying images, sounds, music, etc. for each area having a different recording power so that the difference in the signal intensity of the pits for each area can be confirmed on the monitor screen of the reproducing apparatus of the optical disc 1. Image / audio data.

The asymmetry value (Symmetry value) and I3R
When the (signal modulation) was measured, the results were as shown in FIGS. 2 and 3, and the test optical disc 1 capable of simulating the oxidative deterioration of the cyanine dye could be produced.

In the optical disk 1 of the embodiment, as shown in FIG. 2, when pits are recorded by changing the writing power from 60 to 140, the I3R value (the degree of signal modulation) is changed from 0.1 to 0.1. It has changed to around 0.35. Further, as shown in FIG. 3, it is recorded on the optical disc 1 that the asymmetry value (Symmetry value) decreases when the signal intensity is increased from near 0 to about 10.

[0031]

According to the optical storage medium of claim 1 of the present application,
In the information recording layer of the optical storage medium, a plurality of types of test signals having different asymmetry values and modulation degrees are recorded so as to correspond to the data reproducing capability of the reproducing unit of the optical storage medium. The deterioration of the information recording layer of the optical storage medium can be simulated, and the capability of the reproduction signal of the optical storage medium can be easily selected and determined.

According to the optical storage medium of the second aspect of the present invention, the optical storage medium is composed of a CD-R, so that an optical storage medium for a test can be easily prepared.

Further, according to the optical storage medium of the third aspect of the present invention, since the organic dye is a phthalocyanine dye, the reliability of data recording is improved and high-speed recording is possible.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a cross-sectional configuration of an optical storage medium according to an embodiment of the present invention.

FIG. 2 is a diagram showing a correlation between a signal modulation degree of a pit recorded on the optical storage medium according to the embodiment and a recording power.

FIG. 3 is a diagram showing a correlation between asymmetry of pits recorded on the optical storage medium according to the embodiment and signal intensity.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical disk (optical storage medium) 3 Substrate 4 Information recording layer (organic dye) 5 Metal reflection film 6 Overcoat layer

Claims (3)

[Claims] 1. A rewritable optical storage medium having an information recording layer containing a recordable organic dye and a metal reflection film, wherein the information recording layer has a data reproducing capability corresponding to a reproducing means side of the optical recording medium. An optical storage medium characterized by recording a plurality of types of test signals having different asymmetry values and modulation degrees. 2. The optical recording medium according to claim 1, wherein said optical recording medium is a CD-R. 3. The optical recording medium according to claim 2, wherein said organic dye is a phthalocyanine dye.