JPS62137745A - optical recording medium - Google Patents

Abstract

PURPOSE:To obtain an optical recording medium having diversified kinds of small-scale, information by having the 2nd transparent layer, on which signals are recorded in the form of surface changes, onto the 1st transparent layer which is transparent to light of a specific wavelength and providing a reflective layer on the surface having the deformations. CONSTITUTION:The grooved transparent substrate 1 is preferably formed of a material having no characteristic absorption in a >=400nm wavelength region, for which polycarbonate, etc., are preferably used. The optical recording material 2 is required to be the material which does not possess >=10% spectral absorption characteristic in the oscillation wavelength region of a semiconductor laser, e.g., 750-850nm region and permits, on the other hand, recording by boring by sensing <=750nm laser light. An org. dye, etc. are suitable for such material. The reflective layer 3 is formed on the written pits. A method for vapor deposition of aluminum is optimum for the reflective layer 3.

Description

[Detailed description of the invention] Industrial applications The present invention relates to writable optical recording media.

2. Description of the Related Art Optical recording media, especially optical disks, have been making remarkable progress in recent years, and as the market expands, it is expected that they will be used for a wide variety of purposes and applications. Optical discs can be broadly divided into two types. In other words, there are read-only discs and writable discs, and the former uses a stamper on which information is recorded in advance.
Transparent substrate 6 onto which the information on the stamper was transferred by molding
(Fig. 4) Tens of thousands of discs with the same information are manufactured by vapor-depositing aluminum on the top, and like compact discs for music (hereinafter referred to as CDs),
If a manufacturer mass-produces the product, it can be produced relatively inexpensively even if an expensive stamper is used. However, this method cannot be applied to small-scale production, especially to personal information files, personal music discs, etc., in terms of cost performance. In addition, a writable optical disk, which has recently been in the spotlight, has an optical recording film 9 formed on a transparent substrate 8 with void grooves 12 for rough tracking, as shown in FIG. It had a two-layer structure with plates 1) facing each other. For this reason, although it is suitable for personal use, it is extremely expensive to manufacture. In addition, since the structure is made by pasting two sheets together, CD
It is more than twice as thick as the previous CD player, and has a low reflectance, making it impossible for conventional CD players to play back the written signals. (Reference: Introduction to “Video Discs and DAD”,
(Corona Inc.) Problems that the invention aims to solve: In other words, all conventional methods are: - For individuals to create their own music software, it must be extremely expensive; However, it was necessary to purchase new playback equipment, which effectively became a major hindrance to suppressing the expansion of the optical disc market.

Means for Solving the Problems The present invention provides a writable optical disc at a low cost, has a thin overall thickness of the written optical disc, and has a high reflectance on the recording surface, so that it can be played on a commercially available CD player. It made it possible to do so.

That is, the present invention provides a first method in which a recording film 2 is formed on a transparent substrate 1 in which grooves for performing tracking servo are formed in advance, as shown in FIG. 2, so that the grooves and the reflective side surface are smooth. The first step, the second step (Figure 3) in which a signal is written as a perforated bit string on this smooth recording surface using a focused laser beam of a specific wavelength while applying tracking servo, and the recorded focus The third step is to form a reflective layer 3 on the recording film having columns.

Of these, the grooved transparent substrate 1 used in the first step is preferably made of a material that does not have characteristic absorption in a wavelength range of 400 nm or more, and specifically, polycarbonate or polymethacrylic resin is used. A molded substrate, or a substrate in which grooves are formed using a photocurable resin on a smooth transparent substrate made of glass or methacrylic resin is used. The optical recording material used is a material that has a spectral absorption characteristic of 10% or more in the oscillation wavelength range of a semiconductor laser, that is, a region from 750 nm to 850 nm, and is capable of perforation recording in response to laser light of 750 nm or less. It is necessary that
Organic dyes, organometallic complexes, and their compositions with thermoplastic resins are suitable.

The recording film is formed on the substrate by spin coating or dip coating with a solution containing a recording material.

It can be formed by coating the substrate with roller coating, kiss coating, etc., or by vapor deposition. Note that in order to protect the substrate surface from solvents and temperature increases during vapor deposition, a protective film of several tens of nanometers (hereinafter nm) or less may be previously formed on the substrate surface. The laser used to record signals from an external information source may have a wavelength of 750 nm or less, and may have an oscillation wavelength close to the wavelength that exhibits the spectral absorption of the recording material used. Neon lasers, argon ion lasers, krypton ion lasers, etc. are preferable. Tracking servo is applied to these lasers using grooves formed on a transparent substrate, and signals are written as a puncturing bit string onto a smooth recording surface. A reflective layer is formed on the bit written in this way, and the most suitable method is to vapor-deposit aluminum (hereinafter referred to as An) as the reflective layer. Note that in order to protect the reflective layer, it is also possible to add a step of further applying a protective film over it.

As described above, the optical recording medium of the present invention allows a signal from an external information source, such as a magnetic tape, to be directly written as a perforated bit string onto a recording medium having a smooth surface. The expensive stamper required to manufacture CDs is not required for each information source, so costs can be reduced for small-scale applications.Moreover, by forming a highly reflective layer after recording, it is possible to create CDs with exactly the same structure as conventional CDs. Since it can be made into an optical disc, it has the excellent feature of being able to be played on a commercially available CD player, making it the perfect optical recording medium for personal software and small-scale software production. .

EXAMPLE Hereinafter, an optical recording medium according to an example of the present invention will be described with reference to the drawings.

(Example 1) Thickness 1.2 fl, depth 0.05 μm, width 0.8 μm on the surface
10 nm of SiO□ is sputtered onto the grooved surface of a molded polycarbonate resin substrate 1 on which tracking grooves of 1.6 μm are formed in a spiral shape, and 3.3 μm of iodide is deposited on top of this. '-diethyl-2,2''
- 100% methylene chloride solution of selenacarbocyanine
Spin coded at 0rpa+, recording film 2 with a thickness of 20 nm
was formed. Record! Rotate the substrate on which 2 was formed,
While applying the tracking servo, a 633 nm helium neon laser (output, 20 m
W), 500KIIz, duty ratio 501
50 rectangular pulse signals were written.

Aluminum was vapor-deposited to a thickness of 50 nm on the recording film having the written perforated pits 4 to produce an optical disc. When the created optical disc shown in Figure 1 was played on a commercially available compact disc player, the bandwidth was 30 KHz.
A reproduction C/N ratio of 50 dB was obtained. That is, the optical disc manufactured by the manufacturing method of Example 1 could be played by a commercially available CD player.

(Example 2) On a grooved polymethacrylic resin substrate having the same shape as in Example 1, 1,3"-diethyl-2,2°-quino-thiacyanine iodide was mixed with methanol (8 liquids, 200%
A rectangular pulse signal with a duty ratio of 50150 was written at 500 KHz using an argon ion laser (output: 40 mw). Aluminum was evaporated to a thickness of 40 nm on top of this, and an optical disk was formed. Created.

The created optical disc can be played using a commercially available CD player, with a playback C/N of 49dB with a bandwidth of 30KIIz.
It was confirmed that the ratio could be obtained.

Effects of the Invention By using the optical recording medium of the present invention, small-scale optical recording media having a wide variety of information can be manufactured at low cost, and furthermore, the manufactured optical recording medium can be played by a conventional CD player. It has excellent characteristics.

[Brief explanation of drawings]

FIG. 1 is a sectional view illustrating the optical disc of the present invention, and FIG.
Figures 3 and 3 are cross-sectional views and perspective views showing the state of the medium during the manufacturing process, Figure 4 is a cross-sectional view of a commercially available compact disc, and Figure 5 is a cross-sectional view of a writable optical disc with an air sand inch structure. It is a diagram. 1...Transparent substrate, 2...Recording film, 3.
...Reflection layer, 4...Written bit. Name of agent Patent attorney Toshio Nakao Haka 1 person 10--Ikken fundoshi 1)--Shigozaka 12-Kurazobe Figure 5/Z Ward Ward-~ Hiroshi Castle

Claims (4)

[Claims] (1) A second transparent layer is provided on the first transparent layer that is transparent to light of a specific wavelength, and a signal is recorded as surface deformation on the second transparent layer, and the surface has deformation. An optical recording medium with a reflective layer on top. (2) The second transparent layer is a recording film capable of perforation recording in response to light of a specific wavelength, and is transparent to light of a second wavelength used for reproduction ( 1)
Optical recording medium described in Section 1. (3) The interface between the first transparent layer and the second transparent layer has a reflectance for light of a specific wavelength used for recording, and the reflectance for light of a second different wavelength used for reproduction. Claim (1) characterized in that reflection at the interface is negligible.
Optical recording medium described in Section 1. (4) The first transparent layer has a groove for tracking servo on its surface, a second transparent layer is formed on the surface, and the surface of the second transparent layer is flat. An optical recording medium according to claim (1).