JPS61237239A - Optical disk and optical recording method - Google Patents

Abstract

PURPOSE:To realize a DRAW type optical disk which is applied to CD and CD-ROM by forming a specific bit sequence on specific condition on a color disk which has a film of a pigment or pigment compound on a base as a recording layer. CONSTITUTION:The optical disk is used which has the film of the pigment or pigment compound as the recording layer on the discoid base of a resin material. A semiconductor laser is used as the light source of a device because the device is reducible in size and the pigment uses a material which absorbs semiconductor laser light effectively. A groove for tracking is preferably formed on a recording layer formation surface. This optical disk is irradiated with recording light while rotated at a constant linear speed of 1.2-1.4m/s to form the bit sequence having a gap of 0.84-3.6mum in the recording layer, so that the DRAW type optical disk which is applicable to CD and CD-ROM is realized.

Description

[Detailed description of the invention]! BACKGROUND OF THE INVENTION TECHNICAL FIELD The present invention relates to optical discs, particularly DRAW (direct read after write) compatible CD (compact disc) compatible DRAW (direct read after write) or CD-ROM (read only memory) compatible DRAW optical discs, and a CD format or CD-ROM using this optical disc. The present invention relates to an optical recording method for recording ROM format signals.

Prior art and its problems Compact discs (C, D) are becoming widely used for t-dio, especially for music reproduction.

This CD usually has a pit array containing EFM digital audio signal (CD format signal) information formed on the base surface made of transparent resin such as polycarbonate during injection molding, and then a reflective thin film such as An and a protective film are applied on top of this. A laser beam is irradiated from the back side of the base, and the CD format signal of the pit row is read from the change in reflectance caused by the unevenness of the pits, and music is played back. CDs like this
According to this standard, the inner diameter of the signal surface is 45 mmφ, the outer diameter of the signal surface is 116 mmφ, the pit width is 0.8 m, and the track pitch is 1.6 m.
Rotate at a constant linear speed of 1.4 m/5 ec (F), 6
A maximum recording time of 3 to 74 minutes must be obtained.

However, such conventional music playback CDs are currently only for playback, cannot record, do not have so-called DRAW, and cannot be edited, making it an issue to add DRAW functionality. . In addition, various documents, data,
CD-ROM compatible discs are also required for files such as still images, and DRAW to this CD-ROM is required.
The addition of this function is eagerly awaited.

By the way, as an optical recording medium with a DRAW function,
A phase transition type that uses Te-based chalcogenide as a recording layer and creates a crystalline-amorphous transition to form a recording point by recording light, or a Te-based or organic film that is irradiated with recording light.
Various proposals and practical applications have been made, including a pit-forming type in which pits are formed by melting or removing the irradiated part.

However, in general optical recording media 1, for example, Te system, etc.
The disadvantage is that recording and reproduction with sufficient characteristics cannot be achieved unless the linear velocity is increased and the pit gap is widened.
There is an inconvenience that writing cannot be performed using the recording method of CD or CD-ROM, which performs high-density recording at a slow linear velocity.

(2) Object of the Invention An object of the present invention is to provide a DRAW type optical disc and an optical recording method on which CD format signals and CD-ROM format signals can be recorded.

■Disclosure of invention These objects are achieved by the invention described below.

That is, the first invention has a recording layer on a substrate, and 1.2
An optical disc in which a CD format signal or a CD-ROM format signal is recorded on a recording layer while rotating at a constant linear speed of ~1.4 m/sec, characterized in that the recording layer is a coating film of a dye or a dye composition. This is an optical disc.

A second aspect of the invention provides an optical disk having a coating film of a dye or a dye composition as a recording layer on a substrate.
Recording light was irradiated onto the recording layer while rotating at a constant linear speed of 4 m/see, and the length was 0.84 to 3.6 JLm and the gap was 0.8.
This optical recording method is characterized in that a pit string of 4 to 3.61 Lm is formed to record a CD format signal or a CD-ROM format signal.

■Specific structure of the invention Hereinafter, a specific configuration of the present invention will be explained in detail.

The optical disc of the present invention has a recording layer on a disc-shaped resin base 6 The base size is 120 mm in outer diameter, 15 mm in inside diameter, 1.2 mm in base thickness, and 3 mm in total disc thickness according to the CD standard.
The following are preferred.

The resin material used may be any of acrylic resin, polycarbonate resin, nylon, epoxy resin, etc., provided that it is substantially transparent (preferably transmittance of 80% or more) for recording light and reproduction. is preferred.

It is preferable that tracking grooves be formed on the recording layer forming surface of such a substrate.

The depth of the groove is approximately λ/8n, especially between λ/7n and λ.
/ l 2 n (where n is the refractive index of the substrate)
Furthermore, the width of the groove is approximately the width of a track.

It is preferable that writing light and reading light are irradiated from the back side of the substrate, using the recording layer located in the concave or convex portions of the groove as a recording track section.

With this configuration, the writing sensitivity and the reading S/N ratio are improved, and the tracking control signal is also increased.

The recording layer of the present invention consists of a coating film of a dye alone or a coating film of a dye composition.

By using a coating film of a dye or a dye composition as a recording layer, l. 2~l. At a linear velocity of 4 m/sec,
Length 0.84~3゜6ILm, gap 0.84~3.6μ
When recording m bit strings at high density, a maximum recording time of 60 minutes or more can be obtained.

On the other hand, such recording is not possible with conventional various recording layers, and the dye to be used must be appropriately determined from among those that effectively absorb the wavelengths of the writing light and reading light. Good, in this case these light sources are:
Since it is preferable to use a semiconductor laser because the device can be made smaller, the dyes are cyanine-based, phthalocyanine-based,
Preferred are naphthalene cyanine, squarylium, anthraquinone, azo, triphenylmethane, pyrylium or thiapyrylium salts.

Further, when the dye composition is used as a recording layer, it can contain a self-oxidizing resin such as nitrocellulose, or a thermoplastic resin such as polystyrene or nylon.

Furthermore, a quencher may be included in order to prevent oxidative deterioration of the dye. As a quencher,
Bisphenyldithiol nickel complexes and the like are preferred.

Furthermore, other additives may also be included.

The recording layer can be made of ketone type, ester type, ether type,
A spinner coat or the like may be applied using an aromatic solvent, a halogenated alkyl solvent, an alcohol solvent, or the like.

It is particularly preferable that such a recording layer has a thickness of 0.05 to 0.17 tm.

Depending on the thickness of this recording layer, the above-mentioned CD or CD-RO
It becomes possible to record M format signals.

In addition, when coating the recording layer, the viscosity of the coating solution is 0.5~
10cp, spinner rotation speed 500~l,000
It should be about rpm.

Various underlayers may be formed between such a recording layer and the substrate in order to prevent damage to the substrate due to the coating solvent.

Note that it is preferable not to form a top coat film on the upper layer of the recording layer.
Recording of ROM format signals becomes even easier.

The optical disc of the present invention has a recording layer sealed to prevent dust and dirt from adhering to it.

In this case, the recording layer, more specifically, when the recording layer has a tracking groove, the track portion recording layer of the groove recess is sealed with a gap. This void prevents a decrease in sensitivity.

Although it is sufficient that the gap length is equal to or greater than the depth of the tracking groove, it is usually 0.1 mm or greater.

In order to seal the recording layer in this way, it is possible to integrate a protective plate or protective film onto the substrate having the recording layer so as to create a void above the recording layer, or to seal a pair of substrates having the recording layer with each other. They may be integrated so that the recording layers face each other with a gap between them.

In addition, when sealing, it is preferable to provide a ventilation hole and arrange a filter or the like in this ventilation hole.

To perform optical recording using such a RAW type optical disc, the following procedure may be performed.

Recording is normally performed from the back side of the substrate.

For recording, a semiconductor laser of 750 to 850 mm is usually used. In the present invention, the recording power is 2 to 7
It is possible in the mW range and has extremely high sensitivity.

When recording, move the disc at a speed of 1.2 to 1.4 m/sea.
rotate at a constant linear velocity of

And track width 0, 8 μm, track pitch 1
．． At 6μm, length 0.84-3.6μm, gap 0.8
A pit row of 4 to 3.61 Lm is formed as a spiral track.

At this time, with the EFM-CD format signal, recording for 60 minutes or more is possible with a signal surface having an inner diameter of 50 mmφ and an outer diameter of 116 mmφ.

Reproduction can be performed by detecting the reflected light from the semiconductor laser at the constant linear speed rotation described above.The reproduction power is 0.2~
The power should be approximately 0.7 mW.

Note that during recording, it is preferable to perform tracking control using the above-mentioned tracking groove.

■Specific Effects of the Invention According to the present invention, a DRA compatible with CD or CD-ROM
A W-shaped optical disc was realized, which is extremely advantageous for music editing and various files.

(2) Specific Examples of the Invention Hereinafter, specific examples of the present invention will be shown and the present invention will be explained in more detail.

Example 1. A photopolymer was applied to a thickness of 0.21 Lm on an acrylic substrate with a thickness of 2 mm, an outer diameter of 120 mmφ, and an inner diameter of 15 mmφ, and a stamper was pressed onto it to cure it with ultraviolet rays, resulting in an outer diameter of 116 mmφ and an inner diameter of 45 mmφ. in the range of 0.8
A spiral tracking groove having a width of 1 Lm, a depth of 0.07 JLm, and a pitch of 1.6 μm was formed.

On top of this, hexadecaffeinylthio-Cu-phthalocyanine was applied with a dichloroethane solution, and 0.06 JLm
A thick recording layer was formed.

Next, a protective film was formed on the surface of this disk so that a gap of 0.3 mm existed.

Using the optical disc manufactured in this way, the linear velocity is constant.1.
EFM at 3 m/sec and 5 mW (7) recording power.
-C08 was recorded. The recorded pit row has a length of 0.9 to 3.3 pm and a gap of 0.9 to 3.31 Lm.

As a result, it was possible to record 68 minutes of EFM-CD format signals.

FIG. 1 shows a reproduction pattern when a CD player is reproduced at a linear velocity of 1.3 m/sec with a reproduction power of 0.5 mW.

In this case, the reproduction pattern changes in amplitude as shown in FIGS. 1 and 2 depending on the pit length and pit gap.

The degree of this change B/A (see Figure 2) was measured and found to be 0.65.

On the other hand, the reproduction pattern of a commercially available CD is shown in FIG. 3, the recording time was 68 minutes, and the B/A was 0.64.

That is, the optical disc of the present invention is comparable to commercially available CDs.

On the other hand, in the above case, when the recording layer was changed to a Te vapor-deposited film, reproduction was impossible at a linear velocity of 1.3 m/sec.

Figure 4 shows the reproduction pattern obtained by recording and reproducing the Te film at 0.5 mW and 1.6 m/sec. In this case, B/A was 0.50.

From these results, the effects of the present invention are clear.

[Brief explanation of drawings]

FIG. 1 is a photograph substituted for a drawing of an oscilloscope waveform showing the signal reproduction pattern of the optical disc of the present invention, FIG. 2 is a diagram for explaining evaluation of the signal reproduction pattern, and FIGS. 3 and 4 are . These are photographs in place of drawings of oscilloscope waveforms showing the signal reproduction patterns of a commercially available CD and a comparison optical disc, respectively. Applicant TDC Co., Ltd. Agent Patent Attorney Yo Ishii - and “IP’- FIG. 1 FIG, 2 FIG. 3

Claims (2)

[Claims] (1) In an optical disc that has a recording layer on a base and records a CD format signal or a CD-ROM format signal on the recording layer while rotating at a constant linear velocity of 1.2 to 1.4 m/sec, the recording An optical disc characterized in that the layer is a coating film of a pigment or a pigment composition. (2) An optical disc having a coating film of a dye or a dye composition as a recording layer on a substrate is heated at 1.2 to 1.4 m/sec.
The recording layer is irradiated with recording light while rotating at a constant linear speed of 0.84 to 3.6 μm in length and 0.84 to 3.6 μm in gap.
CD format signal or CD
- An optical recording method characterized by recording a ROM format signal.