JPS6313784A - Addition type optical information recording member - Google Patents

Abstract

PURPOSE:To obtain an optical information recording member suitable for recording and regeneration, by a method wherein, a recording medium consists of three elements, i.e. Bi, Se, and Sb, and the Bi and Se are each limited to be within a specific atomic percentage range in composition. CONSTITUTION:An optical information recording medium 2 is obtained by a deposition method in which Bi, Se, and Sb are respectively put in separate deposition ports and the deposition ports are simultaneously conducted while a substrate 1 is rotated under vacuum conditions. The composition of the medium is preferably Bix Sey Sb1-x-y, wherein x=5-35atom% and y=20-60atom%. After the medium is deposited to be approximately 1,000Angstrom in film thickness, an ultraviolet-curing resin is coated to the surface of the recording medium and cured due to an ultraviolet-light irradiation to form a protective layer 3, then an addition type optical information recording member is obtained. Simultaneously with the deposition, a glass plate is bonded to the substrate 1 to obtain a test piece which is provided with the recording medium 2 on the glass plate.

Description

[Detailed Description of the Invention] [Field of Application for Sedentary Work] The present invention relates to an optical information recording member suitable for application to video discs, digital audio discs, memory discs for combiators, etc., and particularly relates to an optical information recording member suitable for use in recording information. -Relates to a write-once optical information recording member suitable for reproduction.

[Conventional technology]

A write-once optical information recording member usually reproduces information by irradiating the member with an original beam such as a laser beam and detecting reflected light or transmitted light from the member. Furthermore, information can be recorded by applying light beam energy such as a laser beam to the member to physically change one structural state of the recording medium of the member to another structural state. . Chalcogenides are known as such recording media. Chalcogenides can take two different structural states, for example, an amorphous state and a crystalline state. For example, when the recording medium of the amorphous method is irradiated with an original beam and heated to raise its temperature, the medium becomes a crystalline card.

The recording/reproducing method or principle of the optical information recording member as described above is described in Japanese Patent Publication No. 41902/1982, Japanese Patent Publication No. 26897/1987, etc.

In addition, as the recording medium, for example, in the above-mentioned patent publications, various kinds of metals and semiconductors belonging to groups Ⅰ, Ⅰ, V, and Ⅰ in the periodic table of elements, mainly chalcogenides, are used. A combined recording medium has been proposed.

[Problem that the invention seeks to solve]

In the above conventional technology, there are many examples of combinations of elements, and for these reasons, it is difficult to select an appropriate information recording medium for recording and reproduction, and there are almost no examples of waiting for good characteristics at the top. .

An object of the present invention is to provide an optical information recording member suitable for performing recording session reproduction.

[Means for resolving points in between]

The above object is achieved by recording and reproducing information using an optical information recording medium containing the three elements Bi, Se, and 5b.

[Effect]

A thin film made of Bi and St formed by vacuum evaporation undergoes a structural change from an amorphous state to a crystalline state when heated, and the optical properties of the thin film, such as reflectance and modulus, change at this time. The optical properties hardly change until the temperature due to heating reaches crystallization, and the optical properties change immediately after reaching the crystallization chamber.・This has the advantage that even if the recording medium is used in a high temperature environment or stored, the optical properties do not change as long as it is lower than the crystallization temperature, so the life of the conventional recording medium can be extended. However, the optical characteristics are such that the reflectance in the amorphous state is thick due to the large original absorption of lJi, and the change in reflectance of the pre-crystallized plate cannot be uniformly reduced.
When the information was reproduced, the reproduction signal level was low and the quality of the emotion was poor. Therefore, a fifth element is mixed into the thin j-trap made of Bi and Se to have low light absorption (in order to reduce the reflectance of amorphous and odor-deaf materials, and to greatly increase the change in reflectance after crystallization). As the third element, sb was selected, and sb
was formed by vacuum deposition together with Ei and St to obtain a recording medium with low light absorption. As a result, the light absorption coefficient decreased from 1.8 to 0.8 before and after sb was mixed, and the reflectance in the amorphous state decreased from 20% to 12≠. When the medium was irradiated with a semiconductor laser and heated, the reflectance of the conductor increased to 25 cm. This is the number 8 and 2 of 5t.
Almost the same as the elemental medium, the change in reflectance when irradiated with semiconductor laser light 1zJf& could be greatly reduced by the amount that the reflectance of the amorphous λ state was smaller than that of Kotoriko mixed with S and 6.

As a result, a method was adopted for recording information by irradiating the amorphous state of the medium formed by vacuum evaporation with semiconductor laser light according to the emotion, heating it with a knife, and changing it into a different groove shape. .

Here, a suitable composition of the medium is Bix5eySb, -
In terms of atoms, x = 5 to 35 atoms, and y = 20 to 60 atoms. If this is larger than 5 Bi atoms or 5e6 o atoms, the medium has almost no absorption of the semiconductor laser source, and heating cannot be performed using the laser power of the bulk method. Further, if the BL is larger than 35 atoms and the St is less than 20 atoms, the change in reflectance between the crystalline and amorphous states of the medium is small and is not practical. From the above, it is limited to the above range.

〔Example〕

Examples of the present invention will be described below.

Example 1 An example of the present invention will be described with reference to FIGS. 1 and 2. In FIG. 1, 1 is an optically transparent base material, p,
It consists of M, $f A. 2 is a base-like information recording medium, and 3 is a hardened protective film outside the cable. The original tFt information recording medium 2 was prepared by placing Bi, St, and sb in separate evaporation boats, creating a vacuum of 5 x 10-', /'α, and then rotating the base material 1 at a rotation speed of 12 Orpm. While
It was obtained by vapor deposition by simultaneously flowing a t-flow through the above vapor deposition port. Each mixing ratio controls the evaporation rate, and the atomic ratio is Bc26
The composition of Se,s 5b2s was obtained. The film thickness at this time was about 1000.4. Then, an ultraviolet curable resin is applied to the surface of the recording medium and cured by ultraviolet irradiation to form a protective film of about 10 μm, and this is used as a write-once optical information recording member.

At the same time as the vapor deposition, a glass plate with a diameter of 25 mm was attached to the base material 1 to obtain a test piece in which the recording medium 2 was provided on the glass plate. After steaming the test piece and 25
Heat treatment for 50 minutes at 0°C.The spectral reflectance characteristics of the heated pocket were determined as follows.
Shown in the figure. Characteristics after steaming N are shown in Machine 4, and characteristics after heat treatment are shown in Machine 5. B50n, which is the wavelength of the semiconductor laser
m, the reflectance of the recording medium was reduced to 12 by heat treatment.
It has increased to over 31 from Chi.

Next, a recording and reproducing experiment was conducted while rotating the information recording material after vapor deposition at 180 rpm. Laser power 8m
When recording and reproducing in a different structural state by irradiating a signal of 3 JVIiz at F, a high C/N ratio of 5 odB was obtained.

Example 2 Optical information recording members with different compositions were obtained in the same manner as in Example 1, but by changing the deposition rates of Bi, Sa, and 5b. At this point, the composition of the recording medium 2 is Bi,
It was Sb. Moreover, as a result of heat-treating a glass plate test piece at 250° C. for 30 minutes in the same manner as in the example, the reflectance at a wavelength of 8303 m increased from 10% to 28%. In addition, when the write-once type optical information recording member, which has been despised, was subjected to recording/reproduction liquid collection in the same manner as in Example 1, the frequency of 3MHz was
The C/N ratio asdB was obtained.

(Comparative Example 1) Write-once optical FIV information recording members were obtained in the same manner as in Example 1, but with different compositions by changing the deposition rates of Si, Se, and Sb. At this time, the composition of the recording medium is B stones S to S in terms of atoms. Met. In addition, when heat-treated for 30 minutes using a test piece 'k 250' C using a temporary glass as in Example 1, the resistance increased sharply from 10 to 25.

However, when recording and reproducing experiments were conducted on the obtained optical information recording member in the same manner as in Example 1, the C/N was 25 ttB, which was not practical. This means that the recording medium is 850nm.
) This occurs because the absorption is small relative to the BL length, so the current laser power is a non-light component.

In this way, a recording medium mainly composed of Bi-5s-54 has almost no absorption of semiconductor laser light,
There is a compositional region that cannot be heated with the current laser power, and as a result of detailed examination of the composition, it has been found that this condition occurs when the content is less than 5 atoms of Bi or more than 60 atoms of St.

(Comparative Example 2) Write-once optical information recording members having different compositions were obtained in the same manner as in Example 1, but with different evaporation rates of Bi, St, and 56. At this time, the composition of the recording medium is 8 o 5 degrees St, S in atoms. Met. Further, when a test piece made of a glass plate was heat-treated at 250° C. for 60 minutes in the same manner as in Example 1, the thickness changed from 50 inches to 35 pounds. This amount of change is small and poses a practical problem, and when recording and reproducing experiments were conducted on the obtained optical information recording member in the same manner as in Example 1, C/iV 2
It was so small as 0 dB that it was not practical.

In this case, the change in reflectance before and after the heat treatment of the recording medium is small, so the C/N is small. BL.

As a result of investigating other @formations containing Ss and Sb as the main components, it was found that 35 atoms were present, or 1.5g20
If the number of atoms is less than 1, the same situation applies, and C/N is a5
It was less than dB and not practical.

The above examples, comparative power, and other examples are summarized and shown in Table 1.

Table 1 shows the results obtained by changing the composition of four cases other than those mentioned above.

(Remaining days below) Table 1 41.2 is the above-mentioned Examples 1 and 2, and genus 5.4 is the comparison f! It is AJss4. This table lists the three-element composition and C7N ratio for each example. In the judgment column,
It is particularly preferable that the rV ratio is 50 dB or more.

The above results are shown on the triangular tooth shown in FIG. Under the same conditions as in Example 1, the recording and reproducing characteristics were 5-',
The composition with l# and CN ratio of 45 ctB or more is indicated by the solid line 6-7.
-8-9. Here, BL, St
, 5b have a composition of 5 to 35.20 to 60,5, respectively.
~75. This is the range of lfL child chi.

The invention provides a recording medium made of three elements, Bi, Se, and 5h, but is not limited to this (,4
As a 4-element system or a 5-element system, T-2Si, Sn
, pd , In , Gt , etc. (D half-metals, non-pot metals) may be mixed in a small amount of 10 atoms or less without impairing the effects of the present invention.

[Results of invention]

According to the present invention, it is possible to obtain an information recording medium that can perform recording and reproduction using a laser such as a semiconductor laser, and the uses of the original disk can be expanded.

4.1A! Fig. 1 is an Ifr side view of the sickle member according to the invention, Fig. 2 is a graph showing the quantity and characteristics of the present invention, and Fig. 3 is the
FIG. 3 is a diagram showing composition ranges showing good recording/reproducing characteristics of the present invention.

1...Base material 2...Recording medium 3...
Protective Film Agent Patent Attorney Ogawa Ogawa 1 Figure 2 Figure 3b (gz)

Claims (1)

[Claims] 1. In a write-once optical information recording member in which a recording medium is formed on a substrate, the recording medium is composed of three types of Bi, Se, and Sb.
The composition of Bi and Se is 5 to 3, respectively.
5 atomic %, in a range of 20 to 60 atomic %.