JPS6233686A - Light recording material - Google Patents

Abstract

PURPOSE:To enhance a recording sensitivity and a signal quality, by a method wherein a light recording material used for a recording layer in a light recording medium contains a tin and a nickel oxide each having a specific volume content. CONSTITUTION:A recording film 2 contains a tin of 30% or over and a nickel oxide of 20% or over in volume content as integral ingredients. Tin is a metalloid having a low melting point, therefore being sperior in recording sensitivity, but inferior in surface properties, which is caused by its crystallinity. The recording layer containing a nickel oxide in addition to a thin is remarkably improved in the surface properties. The change of NiO volume content in the recording layer to less than 20% results in large noise which causes the poor C/N, i.e. the proportion of signal/noise, and that of Sn volume content to less than 30% results in insufficient recording sensitivity which also causes the poor C/N. Accordingly, the composition range of NiO of 20% or over in volume content and Sn of 30% or over in volume content is practically applicable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an optical recording medium on which information can be recorded and reproduced using laser light. This invention relates to an optical recording medium on which information is formed and recorded.

(Prior Art) A write-once optical tape memory that records and reproduces information on a medium using a laser beam has an excellent feature as a large-capacity recording device because of its high deployment density. As a recording medium for such a write-once optical disc memory, low melting point metals such as Te, Bi, or alloys containing them are used (for example, Japanese Patent Publication No. 15483/1983).

(Problem to be solved by the invention) However, the low melting point metal (Sn, which has a particularly high sensitivity)
The quality of the recording and playback signals was so poor that it could not be put into practical use.

An object of the present invention is to provide an optical recording material for use in an optical recording medium that has high recording sensitivity and good signal quality.

(Means for Solving the Problems) The optical recording material of the present invention is an optical recording material used for the recording layer of an optical recording medium, and contains tin in a volume percentage of 30% or more, and in addition, nickel oxide is contained in a volume percentage of 30% or more. Features (effects) The record according to the present invention is characterized by containing tin with a volume fraction of 30 or more and nickel oxide with a volume fraction of 20 or more. Included as a component. Tin is a metalloid with a low melting point, so it has high recording sensitivity.

However, since the surface quality is poor due to the crystallinity of the material, unrecorded noise is a problem and it cannot be put to practical use. The present inventors have found that the surface properties of the recording layer can be significantly improved by incorporating nickel oxide in a volume percentage of 20% or more in tin, and have thus arrived at the present invention.

The thickness of the recording layer is 100 to 10 (about IOA is the recording sensitivity.

It is desirable in terms of signal quality, and 150 to 5000 A is particularly desirable.

Although the recording layer has sufficiently excellent optical recording properties even if it is a mixture of only tin and nickel oxide, it is necessary to add a third substance or the like to further improve the weather resistance or adjust the reflectance to a predetermined value. It may be included. Third substances include carbon, aluminum, titanium, aluminum, iron, nearhardt,
One or more of nickel, metal, zinc, germanium, zirconium, niobium, molJb, rhodium, palladium, silver, tantalum, tungsten, platinum, and gold is preferable. Most of these exhibit their effects at a volume fraction of about 10 to 15 cm or less, but depending on the physics, they may be included in a larger amount.

1 is a cross-sectional view showing an example of an optical recording medium. l is the substrate,
2 represents a recording layer.

Any substrate can be used, but synthetic resin glass or porcelain is preferable. As a synthetic resin,
Examples include acrylic resins such as polymethyl methacrylate, polycarbonate, boisetherimide, polysulfone, epoxy resins, and vinyl chloride resins. A heat insulating layer or a smoothing layer may be provided on the substrate. The shape of the substrate can be a disk, a sheet, or a tape.

Information is recorded on the recording layer by forming bits on the recording layer. In a disk medium using a disk-shaped substrate, recording is performed so as to form a large number of concentric or spiral tracks. In order to accurately record a large number of tracks at regular intervals, a light guide groove is usually provided on the substrate.

When light enters a groove approximately the diameter of the beam, the light is diffracted.

As Iv in the beam deviates from the groove, the spatial distribution of the intensity of the diffracted light changes, and a guard servo system can be configured to detect this and direct the beam to the center of the groove. Usually, the width of the groove is set to 0.3 to 1.2 μm, and the depth is set in the range ζ of 1/12 to 1/4 of the wavelength of the recording/reproducing laser used.

(Example 1) An embodiment of the present invention will be described below.

An acrylic resin disk substrate with a guide groove having an inner diameter of 15 mm, an outer diameter of 120 mm, and a thickness of 1.2 mm was placed in a vacuum evaporation apparatus, and the vacuum was evacuated to below 2XIO Torr. As evaporation sources, a boat for resistance heating (Sn) was placed, and a boat for electron beam heating was filled with NiO. A recording layer was formed on the disk substrate by co-evaporating the respective deposition substances while controlling the deposition rate using a crystal film thickness monitor.

Table 1 shows the substrate incidence reflectance (wavelength 8300A) when the volume content of NiO in the 3so4 recording layer is changed.
, unrecorded noise level, shows how the signal-to-noise ratio (C/N) changes. here.

The wavelength of the semiconductor laser used for recording and reproduction is 8300X, the signal frequency is 1.2MHz, and the hand @ is 30KHz.
, the linear velocity of the medium is 5 m/sec. Reflectance is Ni
As the O content increases, f tends to decrease, and if the tin content is less than 30%, the reflectance will not reach 1014, which will adversely affect focus servo and pose a practical problem. The unrecorded noise level i decreases rapidly by adding NiO, and reaches a practical level when NiO is contained in an amount of 20% or more.

Therefore, if the volume content of NiO is 20 cm or more and S
A composition range in which the volume content of n is 30% or more is a practical composition range.

Examples in which the film thickness is other than 35OA are shown in Table 2.

It can be seen that in this case as well, the above composition range is favorable.

Table 2\\, + (Example 2) Sn was put in a resistance heating boat, NiO was put in a child beam heating crucible, and Cn was put in another electron beam heating crucible, with a volume fraction of 60%. A recording layer was formed on an acrylic disk substrate by co-evaporating 35 cm and 5%, and recording and reproducing was carried out in the same manner as in Example 1. The C/N was about 50 d.
I made a good record with B.

(Example 3) Put Sn into a boat for resistance heating, put NiO into a crucible for electron beam heating, and put 1-Cr alloy into another crucible for electron beam heating in a ratio of 80:20 with a weight of -lφ. Get in,
A recording layer was formed on an acrylic disk substrate by co-evaporating 55%, 40%, and 5% by volume. Same as Example 1
When I strained the recording and reproduced data, good recording was achieved with a C/N of about 50 dB.

(Example 4) Put Sn into a boat for resistance heating, put NiO into a crucible for electron beam heating, and put FelICr-AA in a weight t% of 70:25:5 in another crucible for electron beam heating! Add alloy and one body ATI is 55%, 40%.

A recording layer was formed on a polycarbonate substrate by codeposition at 5%. When recording and reproducing the same number as in Example 1, good recording was achieved with a C/N of about 4fldB.

(Effects of the Invention) As is clear from the above examples, according to the present invention, an optical recording material with high recording sensitivity and good quality in every issue can be obtained.

[Brief explanation of drawings]

The figure is a cross-sectional view of the Yuan Ji Feng medium. In FIG. 1, 1 indicates a substrate and 2t/'i recording layer. −2゛ 、゛SoI daichi Dainoto patent attorney, wC layer J Haj]': ＼＼〜− Procedural amendment (voluntary) 61.10.28 Showa year month day

Claims (1)

[Claims] An optical recording material used in a recording layer of an optical recording medium, characterized in that it contains tin in a volume percentage of 30% or more, and additionally contains nickel oxide in a volume percentage of 20% or more. .