JPS6230089A - Optical memory medium - Google Patents

Abstract

PURPOSE:To provide an optical information recording medium which has reproducing property and has an improved sensitivity by and mainly containing an organic colorant on a base coating a recording layer having a specific range of light reflectivity. CONSTITUTION:A recording layer which mainly has an organic colorant and 8-20% of light reflectivity is coated on a base. The colorant may be, for example, cyanine colorant, merocyanine colorant, anthraquinone colorant, triphenylmethane colorant, xanthene colorant or phthalocyanine. The light reflectivity of the layer is controlled to 8-20% by (i) adding other colorant that imparts maximum reflectivity to different wavgelength range to the organic colorant, (ii) adding a other colorant which does not have reflectivity but has a coincided maximum absorption to the organic colorant, (iii) adding polymer to the organic colorant, or (iv) forming a multilayer organic colorant recording layers using laminated layers of the colorant having high reflectivity and no reflectivity in terms of laser wavelength.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical information recording medium.

[Prior art and problems]

2. Description of the Related Art Information recording and reproducing apparatuses are known that record and reproduce information by irradiating a rotating disk-shaped information recording medium with a laser beam. The information recording media used in these information recording devices include those consisting of a substrate, a metal reflective film, and a translucent colored layer containing a dye, To, Bl, A, etc.
There are known devices that are composed of a thin film of metal such as s and a substrate.

However, the former has the disadvantage that the metal reflective film f: is expensive because it is formed by a vacuum evaporation method.

In addition, since the latter method involves forming a thin film using a vacuum evaporation method, the cost is high, and the recording sensitivity is low due to its high thermal conductivity and large specific heat.Furthermore, it is toxic and difficult to dispose of. Therefore, an information recording medium has been proposed in which the recording layer is an organic dye qi having metallic luster, such as a cyanine dye.This recording medium uses an organic dye. Therefore, it is easy to match the absorption maximum to the recording radar wavelength, and the reflectance has a value above a certain value near the absorption maximum, making it possible to record and reproduce with a semiconductor radar, and to reduce the size and cost of the device. It has the advantage of being possible.

However, when the reflectance of cyanine dyes and merocyanine dyes exceeds 40% near the absorption maximum light, the absorption rate of the irradiated laser light becomes less than 30 coefficients and the sensitivity decreases. There was a problem that the congregation had to deal with, such as making up for the decline.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an optical information recording medium that has a certain degree of reproduction characteristics and has improved sensitivity.

[Means and actions for solving problems]

As a result of extensive research into the light reflectance of the recording layer, which affects recording sensitivity and playback characteristics, the present inventors have determined that the upper limit of the light reflectance for a recording layer containing an organic dye as a main component is set at 204. It was discovered that the sensitivity was improved and that even if the lower limit of the light reflectance was set to 8, a certain level of playback characteristics could be achieved, and an optical information recording medium with high recording sensitivity and playback characteristics was created. did.

That is, the present invention is an optical information recording medium having a feature that a substrate is coated with a recording layer containing an organic dye as a main component and having a light reflectance of 8 to 20 degrees.

As the substrate, for example, glass, plastic, metal, etc. can be used. In particular, it is preferable to use a glass substrate when considering the adhesion of the organic dye to the recording layer.

As the organic dye, for example, cyanine dye, merocyanine dye, anthraquinone dye, triphenylmethane dye, xanthine dye, phthalocyanine, etc. can be used. Thin films (recording layers) are formed by such methods such as the spinner method, dipping method, doctor blade method, etc.
is formed on the substrate as a.

The light reflectance of the recording layer containing the above organic dye as a main component is 8 to 2.
The following methods can be used to control the temperature to just over 0.

(1) Adding other dyes that give maximum reflectance in different wavelength ranges to organic dyes.

(11) Adding another dye with the same absorption maximum without considering reflective properties to the organic dye.

(i) Adding a polymer to the organic dye.

(iv) A method in which an organic dye recording layer is multilayered, and a layer of a dye having high reflectivity at a Leede wavelength and a layer of a dye having no reflectivity are laminated.

In particular, the method (11) is advantageous in that it improves recording sensitivity. Furthermore, method (iii) is excellent in that it can improve heat resistance through the binder effect of the polymer while maintaining sensitivity.

Other dyes used in the method (1) above include the aforementioned cyanine dyes, merocyanine dyes, and triphenylmethane dyes. The amount of these other dyes added depends on the wavelength position of maximum reflectance, but is in a molar ratio of 2% to 50%, preferably 5% to 30%, based on the main component dye.

Examples of the additive dye used in the method (11) above include an amine type represented by the following formula (I), a 1,2-dithiolate metal complex represented by the following formula (n), and an infrared absorber.

N(R)2N(R2) R; Alkyl group [However, R1 to R4 in formula (n) are an alkyl group or a phenyl group, and X and Y are hydrogen, an alkyl group, a halodane group, MHN
i, Cu, Co, Fe, etc.] The amount of these dyes added is 1 molar ratio to the main component dye.
-50% preferably 5-30 yen.

Used in the method (mountain) above. Examples of the 3f remer include single substances or copolymers of vinyl chloride resin, vinyl acetate resin, acrylic resin, polyester resin, nitrocellulose, polyethylene resin, polypropylene resin, polycarbonate resin, polyethylene terephthalate resin, epoxy resin, and polybutyral resin. I can do it. The amount of these polymers added is O in weight ratio to the dye.
, 1 to 30, preferably 1 to 10.

In the method of Qv) above, the above (1), (ii
) can be used. In this case, an intermediate layer may be provided to protect the thin film layer previously formed on the substrate.

In addition, in the present invention 8A, an intermediate layer and a protective layer may be provided in addition to the organic dye recording layer. The intermediate layer is provided for the purpose of improving the adhesiveness of the recording layer and protecting water, oxygen, and gas. The protective layer is provided for the purpose of protecting the recording layer from dust and oxidation due to water, oxygen, and gas. These layers are composed of the polymer and antioxidant used in the method (iii) above.

Next, the structure of the optical information recording medium of the present invention will be explained with reference to the drawings.

FIG. 1 shows the basic structure of an optical information recording medium, which consists of a substrate 1 and a recording layer 2 coated on the substrate 1 and containing an organic dye as a main component to control light reflection rA. The focused laser beam 3 may be irradiated to any part of the substrate 1 side or the recording layer 29Q during recording and reproduction.

Figure 2 ID is an example using a recording layer consisting of a laminated film of a high reflective dye layer and a low reflective dye layer;
A structure in which a highly reflective dye layer 2a and a low reflective dye layer 2b are sequentially laminated on top of the substrate, and (B) shows a structure in which a highly reflective dye layer 2a and a low reflective dye layer 2b are laminated in sequence.
b shows a structure in which highly reflective dye layers are sequentially laminated.

In such a recording medium, radar light is transmitted to the low reflective dye layer 2.
Set it to 5 so that it enters from the b side.

FIG. 3 shows a recording medium having a structure in which an intermediate layer 4 is provided between the substrate 1 and the recording layer 2, and a protective layer 5 is provided on the recording layer 2. In this case, either the intermediate layer 4 or the protective layer 5 751 may be omitted.

In FIG. 4, two recording media having the same configuration are arranged with a spacer 6 in between so that the recording layer 2 side further faces each other. In Fig. 3, 7 indicates the air hole and 8 indicates the spindle hole.

In this configuration, since recording and reproduction are performed by irradiating the focused radar light 3 from the substrate 1 side, the influence of dirt and rubber can be suppressed.

[Embodiments of the invention]

The present invention will be explained in detail below.

Example 1 40 g of an infrared absorber (trade name: IRGOO2, manufactured by Nippon Kaisha, Ltd.) shown in the following formula was added to a cyanine dye having metallic luster shown in the following (@ formula), and this was added. After dissolving it in a solvent, it was coated on an acrylic resin substrate with a thickness of 1.2M using a spinner method and dried to form a dye recording layer with a thickness of 50 nm to produce a recording medium.

The reflectance and absorbance from the substrate side of the recording layer of the obtained recording medium were measured using a spectrophotometer and found to be 13 and 76, respectively, at a wavelength of 830 nm.

In addition, regarding the recording medium, semiconductor laser light (wavelength 830
nm) was focused on a spot with a diameter of 1.2 μm and irradiated from the substrate side under the conditions of a wire diameter of 3w-1 and a writing time of 1μ■.When recording and reproducing was performed, the recording energy threshold was 2.
, 4n J,/spot, and a reproduction Cβ ratio of 49 dB was obtained.

Comparative Example 1 A recording layer having a thickness of 47 nm was formed on a glass substrate having a thickness of 1.2 m using the cyanine dye of formula (II) used in Example 1 by the osbinner method to produce a recording medium.

The reflectance and absorption rate of this recording layer at a wavelength of 830 nm were 45 and 41, respectively. Also.

When recording and reproducing were performed in the same manner as in Example 1, values of a recording energy threshold of 3.8 nJ/spot and a CA ratio of 46 dB were obtained.

Example 2 Polyester resin (Vylon 200) was added to the cyanine dye represented by the following formula (to) at a weight ratio of 9=1, dissolved in a solvent, and then processed into a 1.2 μm thick film using a spinner method.
Coated on an acrylic resin substrate and dried to a thickness of 70 nr.
n recording layers were formed and the recording medium was advanced.

The reflectance and absorption coefficient from the substrate side of the recording layer of the obtained recording medium were 14 and 70, respectively, at a wavelength of 1330 nm. Recording and reproduction were performed on the recording medium in the same manner as in Example 1. However, the recording energy threshold was 2.8 nJ.
/spot, a ratio of 46 dB f to reproduction c2 was obtained.

Comparative Example 2 The dye shown in formula (7) was used alone as 1 and 2 in the same manner as in Example 2.
A recording layer was formed by coating a 68 nm thick acrylic resin substrate to form a recording medium.

The reflectance and absorption rate of the recording layer of the obtained recording medium were at wavelength 8
At 30 nm, they were 44% and 50%, respectively.

When the recording medium was subjected to omitted reproduction in the same manner as in Example 1, a recording energy threshold of 3.2 nJ/spot and a reproduction C/N ratio of 47 dB' were obtained.

〔Effect of the invention〕

As detailed above, according to the present invention, it is possible to provide an optical information recording medium with high recording sensitivity and good reproduction characteristics.

[Brief explanation of drawings]

1 to 4 are schematic diagrams showing optical information recording media of the present invention, respectively. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Recording layer, 2m... High reflective dye layer, 2b... Low reflective dye layer, 3... Laser light, 4... Intermediate layer, 5...・Protective layer. Applicant's representative Patent attorney Tsuboi, ``Mai Jun Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] The main component is organic dye on the substrate, and the light reflectance is 8 to 20%.
An optical information recording medium characterized by being coated with a recording layer.