JPS6120059B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in signal recording media used in optical video discs and the like, and a method for recording video signals and the like using the improved signal recording media.

Conventionally, a signal recording medium used for an optical video disk or the like is formed by coating a metal film 2 and a resist 3 on a substrate 1, for example, as shown in FIG. 1A. Known methods for recording video information on such signal recording media include a method using photoresist and a heat mode method.

In the above-mentioned signal recording method, the method using photoresist involves exposing the resist coated on the substrate 1 by irradiating it with light or electron beam modulated according to the signal to be recorded, as shown in FIG. 1B. , development, and etching (or metal plating) processes to create a master disk on which signals such as those shown in FIG. 1C were recorded. In addition, the heat mode method
A thin metal film deposited (or sputtered) on the substrate 1 is melted or evaporated by a laser beam modulated by the signal to be recorded, recording video information, and then using a known method to record video information at a wavelength of 1/4 of the readout light. I was creating a depth pit.

However, these conventional methods have the following drawbacks and problems. In other words, in the case of a method using photoresist, the entire surface of the substrate (for example, the size of an LP record, 300φ) has a resolution of about 1μ.
Although it is technically possible to apply the coating uniformly, there are many difficulties and the influence of dust is large.
Therefore, large facilities such as a clean room are required. Furthermore, in the case of the heat mode method, melted and evaporated metal builds up or adheres to the periphery of the pit, which becomes one of the causes of noise when reading recorded information. Furthermore, if the metal film is made thinner to reduce swelling and adhesion around the pit, the depth can be reduced to 1/4 wavelength of the readout light.
It has the disadvantage of requiring many steps such as the use of resist.

This invention solves the above-mentioned drawbacks of the prior art,
It is an object of the present invention to provide a signal recording medium for use in optical video discs, etc., which eliminates problems, and a method for recording video signals, etc. using the recording medium.

Embodiments of a signal recording medium and a signal recording method according to the present invention will be described below based on the drawings.

The signal recording medium shown in FIG. 2 is a cross-sectional side view showing the first embodiment of the present invention, in which a silicon layer 4 is provided on the surface of a substrate 1, and the surface of the silicon layer has a film thickness of several hundred angstroms. A silicon oxide layer 5 is provided, and the thickness of the two-layer structure of the silicon layer 4 and silicon monoxide layer 5 is set to 1/1 of the information readout light.
It is formed by setting about 4 wavelengths.

The signal recording medium shown in FIG. 4 is a cross-sectional side view showing a second embodiment of the present invention. The signal recording medium shown in FIG.
A layer is formed, in which case the depth of the pits can be controlled by means of a metal film 6.

The silicon monoxide used in the signal recording medium of this invention is a material that evaporates easily, but because it is thin and transparent, it absorbs little light, and other metals can be used in place of the silicon material. If you use
There is a risk that the metal part will melt first and the silicon monoxide and metal will separate, but the two-layer film of the silicon layer and silicon monoxide has extremely good adhesion and good results were obtained. . Furthermore, silicon monoxide has a lower thermal conductivity than metals and has the advantage that the spot diameter can be made smaller.

Next, an example of recording video information etc. using the signal recording medium described in the first embodiment of the present invention shown in FIG. 2 will be explained based on FIG. 3.

First, a laser modulated by an optical modulator as shown in FIG. 3B is applied to the silicon monoxide layer 5 of a signal recording medium consisting of a two-layer film of a silicon layer 4 and a silicon monoxide layer 5 shown in FIG. 3A. A beam 8 is irradiated to melt and evaporate the silicon monoxide layer 5 to write information. In this case, silicon monoxide is a substance that evaporates easily, so it sublimes. Next, Figure 3C
As shown in FIG. 3, the silicon layer 4 corresponding to the portion where the silicon monoxide layer 5 has been melted and vaporized is etched using, for example, a potassium hydroxide solution.
At this time, some swelling and deposits around the pit are also dissolved at the same time. Furthermore, as shown in FIG. 3D, a metal film 7 of, for example, nickel or chromium, from which a replica can be taken by electrohoming, is deposited thinly on the surface, and this can be used as a master disc.

Therefore, according to the recording method of the present invention, (1) swelling and deposits around the pits can be removed, (2) the depth of the pits can be easily controlled, and (3) the number of steps can be reduced. (4) Since it does not use photoresist, it has the advantage of not requiring large equipment.

[Brief explanation of the drawing]

1A, B, and C are cross-sectional side views showing the structure of a signal recording medium used in a conventional optical video disk or the like. FIG. 2 is a cross-sectional side view showing a first embodiment of the signal recording medium according to the present invention, and FIGS.
D is a cross-sectional side view showing the process of recording video information etc. using the signal recording medium shown in FIG. 2, and FIG. 4 is a cross-sectional side view showing a second embodiment of the signal recording medium according to the present invention. . DESCRIPTION OF SYMBOLS 1...Substrate, 4...Silicon layer, 5...Silicon monoxide layer, 6...Metal film, 7...Metal film.

Claims (1)

[Claims] 1. A process of irradiating a signal recording medium having a two-layer film of a silicon oxide layer and a silicon layer with a light beam such as a laser beam to evaporate the silicon oxide layer, and evaporating the silicon oxide layer at a position corresponding to the evaporated silicon oxide layer. A signal recording method comprising the steps of etching a silicon layer.