JPS63218398A - Optical recording medium - Google Patents

Abstract

PURPOSE:To provide an optical recording medium which enables easy and inexpensive production of compact disks and video disks in small production quantity and multiple kinds, by providing a recording layer comprising an organic coloring matter having absorption in a semiconductor laser wavelength region and a singlet oxygen sensitizer on a transparent substrate provided with a tracking servo groove. CONSTITUTION:A protective film 2 and a recording layer 3 comprising an organic coloring matter and a singlet oxygen sensitizer are provided on a methacrylic resin made substrate 1 provided with a spiral tracking groove. When semiconductor laser is focused on an optical recording medium thus produced, the recording layer undergoes decomposition or sublimation, whereby a pit is formed. Exposure of a recorded disk to visible rays or UV rays cause fading of the organic coloring matter at unrecorded parts, with the result that the parts become transparent to semiconductor laser, while the shape of the bits is maintained. The organic coloring matter may be a cyanine coloring matter or a squarylium coloring matter. The singlet oxygen sensitizer accelerate fading of the organic coloring matter by photo-oxidation, through sensitizing oxygen contained in air. The sensitizer may be Methylene Blue, Rose Bengale, Erythrocin, chlorophyll or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical recording medium that can be recorded and reproduced using a semiconductor laser.

2. Description of the Related Art In recent years, compact discs and video discs are the most popular optical recording media. In these devices, music and video information is recorded as pits on a transparent substrate, and a reflective layer is provided on the recording surface. In its manufacturing method, information signals are recorded on a smooth glass disk coated with photoresist uniformly using a sophisticated laser recording device, and then developed to create a master disk. Next, Stannogu was created from Mother Mother from this master disc. The information signal is copied onto a transparent substrate by injection molding from a stamper onto which the information signal has been transferred, and by providing a reflective layer on the recording surface, it is possible to manufacture a large number of disks containing the same information. (For example, "Introduction to Video Discs and DAD")
However, in order to manufacture compact discs and video discs, highly precise laser recording equipment and molding machines are required, and a large number of steps are required. When producing information discs in small quantities, there is a problem in that the cost per disc becomes extremely high.

In view of the above-mentioned problems, the present invention provides an optical recording medium that allows production of a wide variety of discs in small quantities at low cost in the production of compact discs and video discs.

Means for Solving the Problems In order to solve the above problems, the optical recording medium of the present invention is a recording medium having a transparent substrate, a dye having absorption in the wavelength range of a semiconductor laser, and a heavy ring oxygen sensitizer. It has layers.

Function: With the above-described configuration, the recording layer is decomposed and sublimated by the focused semiconductor laser, and pits are formed. Next, by exposing the recorded disk to visible light or ultraviolet light, the organic dye in the unrecorded area is bleached while the bit shape is maintained, making it transparent to the semiconductor laser.

As the organic dye, cyanine dyes and squarylium dyes are used. At this time, the -heavycyclic oxygen sensitizer sensitizes oxygen in the air to generate excited singlet oxygen and promotes color fading due to photooxidation of the organic dye, thereby efficiently promoting color fading.

- As the heavy ring oxygen sensitizer, methylene blue, rose bengal, erythrosin, chlorophyll, etc. are used. The disc thus obtained has the same shape as the transparent disc obtained by molding in the manufacturing process of the compact disc or video disc described above.

The apparatus used for recording on the recording medium of the present invention has a structure similar to that of compact disc and video disc players already on the market, by using a transparent substrate in which grooves for tracking servo are formed in advance on the recording medium. This system can be used at a much lower cost than the recording devices used to create masters for compact discs and video discs.

As described above, the optical recording medium of the present invention enables the supply of compact discs and video discs easily and at low cost even in the case of producing small quantities of discs with the same information. can also be handled.

EXAMPLE Hereinafter, an optical recording medium according to an example of the present invention will be described with reference to the drawings. Figure 1 is 1. FIG. 6 shows a partial cross-sectional view of an optical recording medium in a second embodiment.

Example 1 On a surface having grooves on a methacrylic resin molded substrate l having a thickness of 1.2 mm and a tracking groove having a depth of 0.08 μm formed on the surface in a spiral shape at a pitch of 1.6 μm, A protection layer 2 of SiO
: The methylene chloride mixed solution of 1) was spin-coded with 1)00 Qrp to form a recording layer 2 having a thickness of 1)00 nm. While rotating the substrate with the recording film and applying tracking servo, a wavelength of 830 nm was applied at 4 mW through the transparent substrate.
The semiconductor laser was irradiated at a linear velocity of 1.4 m/sec. The recorded signal was 500KHz and a DAT ratio of 5.
0150 pulse and a digital signal for compact discs. After recording, when exposed using a xenon arc lamp, the absorption of the recording layer in the semiconductor laser wavelength range was 200 W-sec, /co! Disappeared by light irradiation. This was 1/3 of the irradiation amount when methylene blue was not included. After fading, 50 nm of aluminum was evaporated onto the recording surface of the disc, and when played on a commercially available compact disc player, the result was 45 d with a bandwidth of 30 KHz.
The C/N of B was obtained, and the music signal could be reproduced.

Example 2 On the same grooved substrate as in Example 1, 10 nm
After forming the S r O2 holding IJi2, a mixed solution of the organic dye of the general formula (n) and methylene chloride (10:1) in methylene chloride was spin-coded at 1)00 Orp to form a film with a thickness of 150 nm! Three layers 3 were formed, and the same signal was recorded under the same conditions as in Example 1. After recording, when exposed using a xenon arc lamp, the absorption of the recording layer in the semiconductor laser wavelength range was 360 W-sec, /
- Disappeared by light irradiation. This was 1/2 the irradiation dose when methylene blue was not included. After fading, 50 nm of aluminum was deposited on the recording surface of the disc, and when played back on a commercially available compact disc player, a C/N of 45 dB was obtained at a bandwidth of 30 KHz, making it possible to play music signals.

FIG. 2 shows a partial sectional view of an optical recording medium in a third embodiment.

Example 3 On the same grooved substrate as in Example 1, lQnm
After forming the protective layer 2 of S i 02, a methylene chloride solution of the organic dye of the general formula (r) was spin-coded at 100° rpm to form a recording layer 3 with a thickness of 1)00 nm, and further on the surface. Then, a chlorophyll aqueous solution was spin-coded at 200 rpm to form a 20 nm sensitizer N4. Example 1
The same signal was recorded under the same conditions. After recording, the recording layer was exposed to light using a xenon arc lamp, and the absorption in the semiconductor laser wavelength region of the recording layer disappeared by irradiation with light of 300 W-sec, /cj. This is 1 when there is no chlorophyll layer.
/2. After fading, a 50nm layer is placed on the recording surface of the disc.
When played on a commercially available compact disc player, the result was 43d with a bandwidth of 30KHz.
The C/N of B was obtained, and the music signal could be reproduced.

Effects of the Invention As described above, the optical recording medium of the present invention can produce a wide variety of products in small quantities by providing a recording layer containing an organic dye that absorbs in the semiconductor laser wavelength range and a -bicyclic oxygen sensitizer on a transparent substrate. This makes it possible to easily produce compact discs and video discs at low cost.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of an optical recording medium according to a first and second embodiment of the present invention, and FIG. 2 is a partial sectional view of an optical recording medium according to a third embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Transparent substrate, 2... SiO2 layer, 3... Recording layer, 4... Singlet oxygen sensitizer layer. Name of agent: Patent attorney Toshio Nakao 1 person I-Transparency 2-Hosowa 3-Recording layer 1rlA Figure 2

Claims (2)

[Claims] (1) An optical recording medium comprising, on a transparent substrate, an organic dye having absorption in the semiconductor laser wavelength range and a recording layer having a singlet oxygen sensitizer. (2) The optical recording medium according to claim (1), wherein the transparent substrate has a groove for tracking servo on its surface.