JPS6048050B2 - information record carrier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an information record carrier suitable in particular for use as a video disc.

A video signal or audio signal is engraved on a flat board, a reflective surface is formed along the uneven surface of the board, a laser beam or other light is irradiated onto this reflective surface, and the reflected light is scattered in accordance with the recorded information. A known method is to convert differences in reflection angles or changes in strength due to light interference into electrical signals using a photoelectric conversion element or the like to reproduce the original signal.

In this case, in order to form a reflective surface with unevenness, the surface of the substrate resin is molded to form unevenness corresponding to the information, and then a metal such as aluminum is deposited on the uneven surface to form the reflective surface. . Alternatively, a method is also used in which a reflective surface is formed in advance by metal vapor deposition, and then irregularities are formed on the reflective surface by molding.
All of these methods create an uneven surface that corresponds to signal information on the light reflecting surface itself, but these methods are susceptible to rust due to oxidation in the air because the metal surface is exposed on the disk surface. Also, the metal surface becomes dirty due to touch with fingers, etc., which changes the reflectance of light and causes information to be distorted.

Furthermore, it is unlikely that video discs created using this method will be compatible with playback devices that physically scan the signal grooves and extract signals using pressure-sensitive elements or capacitance. . This is because the metal films on these surfaces do not have sufficient wear resistance and do not have the required compressive elasticity. Therefore, an object of the present invention is to prevent rust and dirt from adhering to the metal reflective surface, to always obtain good light reflection, and to provide a method that can be used with various other reproduction methods, such as physically scanning the signal groove. T to extract the signal using the pressure sensitive element
ED method, RCA that extracts signals by electrostatic induction
It is an object of the present invention to provide a compatible information recording carrier that can also be used in playback devices such as those of the present invention.

Embodiments of the present invention will be described in detail below with reference to the drawings.

In FIG. 1, numeral 1 is a transparent resin layer, 2 is a metal reflective surface, and 3 is a base metal disc. The upper surface of the base metal disk 3 is a flat surface, and therefore the metal reflective surface 2 is also a flat reflective surface. Convex portions 4 and concave portions 5 corresponding to recorded information are sequentially formed on the upper surface of the transparent resin layer 1 along the recording direction 6. It is desirable for the transparent resin layer 1 to be made of a material having a relatively high refractive index of light, and for example, vinyl chloride resin, acrylic resin, styrene resin, olefin resin, etc., which are available in Ichiyang, have moldability suitable for this invention. It has been confirmed that the necessary fine signal molding can be obtained by heating and pressurizing molding using the opposite plate.

In addition, these resins also have light convergence and diffusion properties of 1.1 to 1.
It has a refractive index of 1.6, and was confirmed to have satisfactory properties in terms of the desired lens effect. For example, in the case of vinyl chloride resin, soft vinyl chloride resin and hard vinyl chloride resin are heated and molded to create lenticular shapes.
A sheet was created and used to elucidate the mechanism and implementation of photoimage formation. FIG. 2 shows an example of reflected light with respect to incident light.

The shape of the unevenness on the signal surface is usually considered to be the same as the shape of an FM modulated signal, but on an actual disc, it is reversed from the master to the stamper and then to the disc! The molded shape is slightly different from that of a signal, and the final result is a groove shaped like an array of convex and concave lenses, which usually occurs in submicron units such as video discs, or in inversion and molding. That's true.
That is, when the incident light beam is at the position of the convex part 4, this convex part acts as a convex lens and the incident light beam converges, and when it is at the position of the concave part 5, this concave part 5 acts as a concave lens and the incident light beam converges. be diffused. Therefore, if the photoelectric conversion light receiving section is set at a certain position relative to the incident light beam, for example, on the same axis as the incident light beam, the amount of reflected light that reaches it will change depending on the unevenness of the resin layer 1, and this change will be It can be extracted as an electrical signal through photoelectric conversion. In the example shown in FIG. 2, the focal point of the convex lens and concave lens formed in the convex portion 4 and concave portion 5 is exactly on the reflective surface 2, but
Even when the focal point is further toward the resin layer 1 or the base 3 than the reflective surface 2, signal reproduction can be performed in the same way. Figure 3A is F
In the case where the frequency of the M modulation signal is high and the radius of curvature of the convex portion 4 is small, the focal point is within the resin layer 1, and the parallel incident light beam is reflected by the reflective surface 2 after being focused at the focal point, and the convex portion 4 has a small radius of curvature. It converges outside of 1.

FIG. 3B shows a case where the frequency is low and the radius of curvature of the convex portion 4 is large, the focal point is further below the base body 3 as indicated by the dotted line, and the parallel incident light beam enters the resin layer 1. It advances toward the focal point located below the base 3, is reflected by the reflective surface 2 on the way, and is focused at a position within the resin layer 1 that is exactly equal to the distance from the reflective surface 2 to the actual focal point, and the resin layer 1
Converged outside.

FIG. 4A is a specific example (for the high frequency case shown in FIG. 3A), shown in perspective at the reflective surface 2 for clarity of explanation.

The frequency of the signal was 4.2 MHZ, the radius of curvature R of the convex lens was 4.48 μm, the focal length f was 13.7 μm, and the distance from the apex of the convex portion 4 to the reflective surface 2 was 20 pm.
Further, Fig. 4B is a specific example of the low frequency case shown in Fig. 3B, where the signal frequency is 2.8M pressure, the radius of curvature of the convex lens R = 9.99μm, and the focal length f = 29.38p, m.
1 The distance from the vertex of convex part 4 to reflective surface 2 is also 20μ
It was m.

3A and 3B both show cases in which light converges in the convex portion 4, and in the case of the concave portion 5, although not shown, the light naturally diffuses.

Therefore, there is a large difference in the amount of reflected light between the convex portions 4 and the concave portions 5,
Also, there is a slight difference in the amount of light depending on the frequency, so
A reproduced signal waveform substantially corresponding to the shape of the unevenness can be obtained. In this way, signal detection using reflected light can be performed in the same way as the Phillips method. Further, in the embodiment shown in FIG. 1, the pressure-sensitive scanning body is brought into contact with and slid on the irregularities on the upper surface of the resin layer 1 by physical scanning with a stylus, rather than optical reproduction as described above. Reproduction using the so-called TED method is also possible. In this case, a surface preparation technique has been established in which a vinyl chloride resin dissolved in an organic solvent is applied onto the metal surface. As a result, it has sufficient elasticity and abrasion resistance, and has an abrasion resistance equal to or higher than that of video discs made from ordinary hard vinyl chloride sheets. For example, thickness 0.
047707! A substrate is prepared by cleaning the surface of a thin nickel disk having a hardness of 190 using a solvent.

The thickness and hardness of the thin nickel plate are such that it allows the disk to rotate while maintaining an air layer on the saddle-shaped fixed base of the playback device.
When used in the ED method, this is an important element to perform deformation within the elastic limit that is sufficient to bend along the saddle shape and to allow repeated restoration up to 2 million times. In addition, it must be able to be economically obtained in the market in large quantities with uniform thickness, and nickel thin plates satisfy this condition in this respect as well. A vinyl chloride resin in which a solvent is dissolved is applied to the surface of such a nickel thin plate using a roll coater (rotary coating machine) and dried. Coating is performed twice at a thickness of 10 pm each time to reduce uneven coating and eliminate missing parts. Also, as mentioned above, this thickness is the thickness to provide performance equivalent to that of the lens after molding, and is determined in relation to the size and depth of the signal unevenness and the distance between the light receiving part and the disk surface. The distance should be 20 μm. If it is thicker than necessary, the light transmittance will drop, and if it is too thin, it will seriously lack uniformity, and the ratio of unevenness to thickness will become undesirable. It is difficult to mold fine signals without

Any of the proposed methods may be used to uniformly coat the metal plate base with resin. As the coating resin, a vinyl hydrochloride copolymer resin was made into a solution using a transparent solvent, and no substances that would interfere with transparency, such as colorants that are normally added, were used. Next, using this sheet, for example, at 140°C,
A video disc was obtained by processing for 6 seconds under heat and pressure of 150 kg/Cd, and then cooling. This disk was not only suitable for a reproduction device using reflected light, but also provided a good reproduction signal with a reproduction device using a contact pressure-sensitive stylum. In this example, the nickel substrate serves as the counter electrode, and the capacitance that changes due to the unevenness of the transparent resin layer sandwiched between the electrostatic pickup and the electrostatic pickup can be converted into electrical output. It can also be applied to methods. In addition to the reflected light method, optical reproduction methods include a transmitted light signal reproduction method known as the Thomson CSF method, and the present invention provides a disc that is compatible with these methods as well.

FIG. 5 shows a cross section in the scanning direction. The surface of the transparent resin layer 1 has a concavo-convex signal surface similar to that shown in FIG. The bottom surface of this resin layer 1 is in contact with the aluminum vapor deposition surface 2a, and further in contact with the transparent resin layer base 3a. That is, the transparent resin base layer 3
Prepare a transparent vinyl chloride sheet with 0.1 ugliness as a,
Aluminum is vapor-deposited on this flat top surface to create a reflective and transmissive surface 2.
a is formed. This layering and aluminum vapor deposition are uniformly performed on the upper surface of the base layer 3a, and the optical reflection and transmission characteristics are selected to be exactly 50% each. Next, a resin layer 1 of vinyl chloride is applied to protect this vapor deposition surface. This is formed by applying a solution dissolved in the above-mentioned solvent to a thickness of about 20 μm and drying it. Thereafter, the unevenness information shown in FIG. 5 was formed on the surface of this transparent resin layer 1 using an ordinary molding machine. FIG. 6 shows the state of reflection and refraction of incident light during reproduction in the embodiment shown in FIG.

That is, in the convex portion 4, the parallel incident light is focused on the translucent aluminum vapor deposited surface 2a by the convex lens action, half of it is reflected along the incident optical path, and the rest is reflected on the aluminum vapor deposited surface 2a.
The light passes through the transparent base layer 3a. Further, parallel incident light is diffused in the concave portion 5 by a concave lens action, 50% of the light is reflected by the aluminum vapor deposited surface 2a, and the rest is transmitted through the base layer 3a and further diffused. Therefore, the base layer 3
By providing a photoelectric conversion element below a, good signal reproduction using transmitted light can be achieved. In the case of the embodiment shown in FIG. 5, it can be applied not only to signal reproduction using reflected light but also to a contact type reproduction method and a capacitance type reproduction method using the aluminum vapor-deposited surface 2a as a counter electrode, and has good compatibility. realizable. As described above, the information recording carrier according to the present invention is compatible with each currently known reproduction method, and can not only reproduce signals using any method, but also has a simple structure and can be formed from easily available materials. Since the metal surface is not exposed, there is no risk of rust, dirt from touching, etc., and good playback characteristics can be maintained.

Therefore, there are advantages such as no special protective layer or special material is required, and conventional manufacturing equipment can be used as is.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the recording unevenness of an embodiment of the present invention, FIG. 2 is a view showing the path of light during reproduction, and FIG. 3A is a view showing the path of light during high-frequency signal recording. FIG. 4A and 4B are diagrams explaining FIGS. 3A and 3B in detail, respectively, and FIG. 5 is another embodiment of the present invention. FIG. 6 is a diagram showing the path of light during reproduction in the embodiment of FIG. 5. 1... Transparent resin layer, 2... Reflective surface, 3
... Base body, 4 ... Convex part, 5 ...
・Concavity.

Claims (1)

[Scope of Claims] 1 A device comprising a base, a reflective surface formed on the surface of the base, and a transparent resin layer provided on the reflective surface and having unevenness formed in accordance with recorded information, wherein the unevenness is act as a concave lens and a convex lens for a light beam incident through the transparent resin layer and reflected by a reflecting surface. 2. The information recording carrier according to claim 1, wherein the base is made of metal, and a reflective surface is formed on the surface of the metal base. 3. The information recording carrier according to claim 1, wherein the reflective surface is a metal vapor deposited layer formed on the surface of the substrate. 4. An information recording carrier according to claim 1, wherein the base is made of a transparent material, and the reflective surface is a metal vapor deposited layer having a light transmittance of about 50% for vertically incident light. 5. An information recording carrier according to claim 1, characterized in that the recorded information is frequency modulated.