JPH0253856B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for duplicating ultra-high density recording discs such as video discs or digital audio discs.

In ultra-high density recording disks such as video disks or digital audio disks, information signals such as video signals or audio signals are e.g.
It is recorded on the disk substrate in a spiral or concentric manner at a very high density on the order of 1.35 μm pitch (740 lines/m) or 1.57 μm pitch (640 lines/m), and therefore Sufficient care is required when copying.

Conventionally, the method of duplicating such disks has been limited to molding plastic materials by injection or pressing, regardless of the recording/reproducing method used.

However, this method of duplicating disks by injecting or pressing requires large, expensive, and complicated molding equipment, consumes a large amount of plastic material and energy for molding, and costs 10 to 100 yen per disc. It takes a long molding time of 30 seconds. Furthermore, the above method of duplicating disks by injecting or pressing has the disadvantage that it is not possible to completely prevent molding defects due to air bubbles and foreign matter that cause dropouts during playback.

The present invention has been devised in view of the above-mentioned prior art and provides a method for duplicating a disk by which information signals can be reproduced accurately and easily in a short period of time.

A feature of the present invention is that a transparent master, in which information signals are recorded in a concavo-convex manner in a V-shaped groove, is brought into close contact with a photographic material, and by irradiating light through the master, the concavo-convex signals of the master are processed into a photographic effect. The photosensitive material is transferred onto a photosensitive material, and this photosensitive material is developed to obtain a signal on the photosensitive material consisting of a blackened portion and a transparent portion corresponding to the uneven signal of the master.

The present invention will be explained in detail below based on embodiments of the drawings.

Figure 1 shows the transparent material known as the master.
An explanatory diagram showing a state in which a TED method video disk is placed in close contact with a photosensitive material and exposed by irradiating light from the master side. Figure 2 shows the photosensitive material after exposure and development are completed. FIG. 3 is a diagram illustrating the relationship between the wavelength of the unevenness of the master signal and the focal length, and FIG. 4 is a diagram illustrating the reproduction system.

In Figure 1, 1 is a transparent master,
Here, we will use a reverse version of the TED format video disc as master 1. That is, the TED system video disc used for normal playback has signals recorded in a V-shaped groove with concavities and convexities, and therefore, in the present invention, the reverse version, which is Master 1, has V-shaped peaks. This means that a signal of unevenness is recorded in the part.

2 is the disk material on which the signal is formed. This is made up of a photographic material layer 4 provided on a substrate 3 made of synthetic resin such as vinyl chloride, acetate, polyester, etc. This photographic material may be of either a positive type or a negative type. In any case, it is preferable to use a high-contrast material, and the thickness is 1 μm to 1 μm.
It is desirable that the thickness be within the range of 6 μm, but to enable short wavelength recording, the thinner the layer is, especially 1.5 μm.
Preferably before and after.

The above-described master 1 is placed on the surface of the photosensitive material layer 4 of such a disk material 2 so that its signal recording surface is in contact with the surface, and light is irradiated from the master 1 side for exposure. The light incident on the master 1 is converged and diffused because the concave and convex portions of the signal on the master 1 function as a lens, and then reaches the photographic material.
Here, since the surface of the master 1 on which the light enters is flat, even if there is a thickness error in the master 1, there is no effect on the convergence and diffusion of the light. Also, the most common light source is a mercury lamp, and it is best to irradiate from a distance of 70 to 100 cm. The laser beam may be diffused or directed in the X direction and the Y direction for surface exposure.

When the photosensitive material layer 4 exposed through the master 1 and developed is a positive type, as shown in FIG. 2, the areas where the light is concentrated are blackened and become opaque, and the areas where the light is diffused are blackened. The signal becomes transparent and recorded without any interference.

That is, since the photographic material layer 4 used in the present invention has a high contrast, by keeping the exposure amount constant, a signal 5 (opaque portion) corresponding to the magnitude of the wavelength of the unevenness signal of the master 1 can be obtained. This is possible.

In addition, in the case of a negative type photosensitive material, the part where the light is diffused is blackened and becomes opaque, contrary to the positive type, and the part where the light is concentrated is not blackened but becomes transparent and a signal is recorded. .

Further, arrow A in FIG. 2 indicates the recording direction of the signal, and the signal is recorded in a spiral shape.

By the way, the resolution and sensitivity of photographic materials have reached a point where they are quite high, and it is easy to achieve a resolution of 2,000 to 3,000 lines/mm, making it easy to record information signals such as video signals or digital audio signals. Gain,
Furthermore, higher resolution than conventional technology can be expected.

Further, since signals are optically recorded on the photographic material layer 4, the lens properties of the uneven signals of the master 1 are an important issue. FIG. 3 shows the relationship between the wavelength and focal length when the amplitude of the unevenness of the signal of master 1 is 0.12 μmPP. As is clear from this, for example, when the signal wavelength is 4.6 μm, the focal length is 22 μm;
When the focal length is 1.7μm, the focal length is 3μm, and Master 1
It is understood that the irradiated light is condensed and diffused with regularity according to the uneven signal, and the signal is faithfully recorded on the photographic material 4.

A disk D can be obtained by cutting out the disk material 2 into a disk shape, in which signals are recorded in the transparent portion and the opaque portion (blackened portion) on the photographic material layer 4 in this manner.

To reproduce a disc on which signals have been recorded as described above, for example, as shown in FIG. 4, the disc D of the present invention is placed on a transparent turntable 11, and the disc is rotated by a motor M. ,
A light source 12 emits light toward the disk D from below the turntable 11, a light receiving section 13 above the disk D receives the light that has passed through the disk D, and converts the intensity of the light according to the signal recorded on the disk into an electrical signal. It can be played by doing this. The light receiving section consists of a light collection system using a lens and a photoelectric conversion section, and the light source 11 may be coherent light such as a laser beam, but it is also possible to reproduce the signal with ordinary light such as an incandescent light bulb. .

As described above, the present invention is a completely new method for duplicating a disc on which information signals such as video signals or digital audio signals are recorded, and the recording of signals does not rely on physical deformation as in the conventional method. This makes it possible to record in an extremely short time.
Moreover, it does not require large-scale equipment,
Moreover, it is extremely excellent in that it can accurately reproduce the information signal of the master.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is an explanatory cross-sectional view showing the state in which signals are recorded, FIG. 2 is a plan view of the disk material on which signals are recorded, and FIG. FIG. 4 is an explanatory diagram showing the relationship between the wavelength of the unevenness of the master signal and the focal length, and FIG. 4 is an explanatory diagram of the reproduction system. 1...Master, 2...Disk material, 3...
Disc base, 4...Photosensitive material layer, 5...Signal,
11...turntable, 12...light source, 13...
...Light receiving section, D...Disk, M...Motor.

Claims (1)

[Claims] 1. On a disk material having a photosensitive material layer on the surface, a transparent master having a concavo-convex signal portion is superimposed closely on the photosensitive material layer, and light is irradiated so as to reach the photosensitive material layer through the master. . A method for duplicating an information recording disk, in which a signal consisting of a blackened part and a transparent part corresponding to the uneven signal of the master is obtained by developing this photographic material layer.