JPS6145437A - optical recording member - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention is suitable for optical reflective or transmissive video discs, or digital audio discs (particularly suitable for improving the durability of optical recording films). The present invention relates to an optical recording member.

[Background of the invention]

For example, as an optical recording member that forms an optical recording film whose refractive index, reflectance, etc. changes upon irradiation with a laser beam on a substrate, and records and reproduces information such as analog and digital signals at high density. , Japanese Patent Publication No. 52-13814
Publication No. 5 is known. In this method, a laser beam is narrowed down to a minute spot using a lens or the like, and the optical recording film is heated to cause a phase change, thereby making it possible to record high-density information.

These optical recording films, such as thin films such as TeOx and Bi, are designed to have a film thickness that takes advantage of the coherence of light so that they can absorb a large amount of energy in the wavelength range of the laser beam used for recording and erasing. There is.

On the other hand, it is becoming increasingly desirable for these optical recording members to be used in harsh environments, and for example, it is necessary that the recording/reproducing characteristics do not change much even after long-term exposure to direct sunlight. Conventionally, substrate materials for forming optical recording films include glass, polymethyl methacrylate (PMMA), and polycarbonate (
A transparent material such as PC) is used, which is insufficient to block short wavelength rays included in sunlight and protect the optical recording film over a long period of time.

[Purpose of the invention]

An object of the present invention is to provide an optical recording member that exhibits little deterioration in long-term recording and reproducing characteristics even under harsh environments.

[Summary of the invention]

In the present invention, the light transmittance is high in the wavelength region of laser light used for recording, reproducing, and erasing information, and the light transmittance is low in the near-ultraviolet and ultraviolet light regions where light energy is high. The recording film is protected from sunlight, etc.

That is, the substrate has a light wavelength of 300 nm to λ compared to the wavelength (λ0) of a laser beam used for optical recording/reproduction.
A material having a light transmittance of 40% or less in the wavelength range of 0 is used.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings and the like. The optical recording film 1 used as an example of the present invention was, for example, a two-layer structure film consisting of 5bzSe3 and Bi, which was formed into a thin film on the substrate 2 by a method such as vacuum evaporation. The structure of such an optical recording member 3 is shown in FIG. The substrate 2 was a PMMA resin substrate unless otherwise specified.

Furthermore, the evaluation of optical recording characteristics shows that the wavelength (λ0) is 830
Changes in reflectance were determined using a nm semiconductor laser.

Example 1 The PMMAm resin substrates used as an example of the present invention were colored with organic dyes.
Summer green (2b) on 63.

530 Gray Smoke (2c), 550 K Sepia Smoke (2d), Barapet D-39-004 (2
e).

And for comparison, colorless and transparent Como Glass Clear (2f
) was used. 300nm to 1500n of these resin substrates
Figure 2 shows the light transmittance in the m region.

These resin substrates 2a to 2e have low light transmittance in the vicinity of 500 to 8001 m.

An optical recording film 1 was formed on these substrates, and as shown in FIG. 3, irradiation with a cannon lamp having a spectrum close to that of sunlight was performed from the side of the substrate facing the recording film 1.

FIG. 4 shows the change in reflectance of the recording film as a function of the Canon lamp irradiation time.

As a result, the reflectance change of the substrate 2e with a small light transmittance of 800 nm or less is the smallest, compared to the conventional substrate.
Durability has been significantly improved.

Example 2 Other embodiments of the invention will be described below.

The substrate used in this example was Como Glass 302K cobalt flue (2,5') manufactured by Kyowa Gas Chemical Co., Ltd.

Parapet $18009 Violet (2h),
It has spectral characteristics as shown in FIG. This substrate material has a so-called light window with high light transmittance in the vicinity of 300 nm to 500 nm, and blocks light in the vicinity of 500 nm to 800 nm. On this substrate surface, 360 nm
A photosensitive ultraviolet curable resin 4 is coated nearby, and the cured resin layer 4 is irradiated with a high-pressure mercury lamp from the substrate 2, 9, 2h side according to the so-called photosensitive resin film forming method (2P process). Formed. On this resin cured layer 4,
The optical recording film 1 was formed and the durability was enjoyed in the same manner as shown in Example 1. Results tf: The durability was significantly improved compared to the rice (1) substrate 2f. Here, the resin cured layer 4 has 36
Because it has light absorption near Onm, it is a group.

Light window of board 2, 9, 2h (300nm ・-soon
m) is blocked. This result shows the same effect as in Example 1.

As explained above, according to the present invention, the durability of an optical recording member used in a harsh environment is improved. Although PMMA resin was used as the substrate material in the embodiments of the present invention, it goes without saying that the present invention can also be applied to materials having the spectral characteristics that are the subject matter of the present invention, such as colored glass and colored polycarbonate. Furthermore, the transparent disk f
Even if the five surfaces are coated with a resin having the spectral characteristics that are the gist of the present invention, they are more effective than when no treatment is applied.

〔Effect of the invention〕

According to the present invention, a highly durable optical recording member can be obtained by adding a colorant that absorbs and blocks light of a specific wavelength into the substrate material.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an optical recording member to which the present invention is applied, FIG. 2 is a diagram showing the spectral characteristics of a substrate used in an embodiment of the present invention, and FIG. 6 is a diagram showing the effects of the present invention. FIG. 4 is a diagram showing the effects of the present invention, FIG. 5 is a spectral characteristic diagram of the substrate used in other examples, and FIG. 6 is a diagram showing the evaluation method used in this invention. FIG. 7 is a sectional view of an optical recording member used in another embodiment according to the invention. 1... Optical recording film 2... Substrate 4... Ultraviolet curing resin

Claims (1)

[Claims] 1. In the substrate material of an optical recording member that records/reproduces by irradiation with a laser beam, the wavelength of the light is different from the wavelength (λ_0) of the laser beam used for optical recording/reproduction. An optical recording member characterized by using a substrate having a light transmittance of 40% or less in a wavelength range of 300 nm to λ_0. 2. The substrate has a resin cured layer on its surface, has a peak light transmittance of 50% or more in the wavelength range of 300 nm to 500 nm, and has a light transmittance of 40% or less in the 500 nm to λ_0 range. An optical recording member according to claim 1, characterized in that: 3. The substrate is glass, polymethyl methacrylate,
2. The optical recording member according to claim 1, wherein one surface of a transparent substrate made of polycarbonate or the like is coated with a surface coating having the above-mentioned light transmittance.