JPH02177029A - Optical information recording medium - Google Patents

Abstract

PURPOSE:To obtain the medium which obviates the degradation of reflectivity and substantially prevents the spread of recording pits by successively forming a reflecting film in a fine crystalline or amorphous state essentially consisting of Te and an inorg. oxide film directly or via an inorg. oxide film on a substrate. CONSTITUTION:The reflecting film 2 is formed on the substrate 1. The reflecting film which consists essentially of the Te, is incorporated with >=1 kinds of the elements selected from the prescribed group of Al, Si, Ti, etc., in a prescribed range and is in the fine crystalline or amorphous state is used for the reflecting film 2. The inorg. oxide film consisting of glass, SiO2, etc., are formed thereon. The medium which obviates the degradation of reflectivity and substantially prevents the spread of the recording pits is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical information recording medium such as an optical disk or an optical card that records information by forming convex portions using a laser beam.

[Problems to be solved by conventional techniques and inventions] Conventionally,
It has been proposed to form bits and record information by irradiating a recording film with a laser beam. For example, a medium has been proposed in which information is recorded by forming a hole (focus) using a Te-based alloy as a recording film. However, Te has drawbacks such as being easily oxidized and having a low reflectance, resulting in a short life span, and recording bits being prone to widening, making the pulse width of the reproduced signal longer than the recording pulse width.

[Means to solve the problem]

The present inventors have developed an optical information recording medium that records information by forming convex portions upon receiving a recording beam, which includes a substrate and Te formed directly on the substrate or through an inorganic oxide film as a main component. By using a reflective film in a microcrystalline state or an amorphous state and further providing an inorganic oxide film on this reflective film, it is possible to obtain an optical information recording medium that does not have a decrease in reflectance and in which recording bits are difficult to spread. This discovery led to the completion of the present invention.

That is, the present invention provides an optical information recording medium in which information is recorded by forming convex portions upon receiving a recording beam. The present invention relates to an optical information recording medium characterized by having a reflective film in a microcrystalline state or an amorphous state, and an inorganic oxide film provided on the reflective film.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a sectional view showing one embodiment of the optical information recording medium of the present invention, and FIG. 2 is a sectional view showing another embodiment of the optical information recording medium of the present invention, in which 1 is a substrate, 2 is a reflective Film 3 is an inorganic oxide film.

The substrate 1 used in the present invention is generally disk-shaped, but may also be card-shaped or drum-shaped. Substrate materials include transparent plastic materials such as polycarbonate resin, polymethyl methacrylate resin, epoxy resin, or amorphous polyolefin; Alternatively, glass is used.

The reflective film 2 used in the present invention is a microcrystalline or amorphous reflective film containing Te as a main component. This reflective film consists of Te, AI+SI+Tj+ν, and Cr.

Mn, Co, Nt + Cu, Zn+ Ga+ Ge+
8s to Ss, Y+Zr+Nb, Mo+Pd, Ag.

CtL In+Sn, Sb+ Ta, Pt, ^u, Pb
and Bi, the composition of which is 50≦X as TexMα.
Preferably, ≦99, 1≦α≦50. However, X and α are atomic %, and h represents at least one element selected from the group of elements other than Te. The thickness of this reflective film varies depending on the application, but generally the film thickness that provides a good C/N ratio is 1.
It is preferably 0r+m or more and 1100ri or less, and more preferably 10nm or more and 50nm or less.

The inorganic oxide film 3 used in the present invention is made of glass, 5iOz
+ Sin, TtOz+ Y! Oh A1zO3+
ZnO,a,o,.

It is a thin film of Zr0z, GeO□, or a composite thereof, and the thickness thereof is preferably 5 nm or more and 200 nm or less, more preferably 5 new or more and 100 no+ or less, from the viewpoint of recording sensitivity.

The reflective film 2 and inorganic oxide film 3 used in the present invention can be formed by a vacuum evaporation method, a sputtering method, or an ion blasting physical thin film formation method.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Te was applied to a φ130M polycarbonate resin spiral grooved disk substrate by DC sputtering.

A microcrystalline film made of Se (composition Te: 5e=9
5:5 (atomic ratio)) was formed to a thickness of 40 nm, and then alkali-free glass was formed to a thickness of 40 nm by RF sputtering.

The wavelength 8
Using a 30nn+ semiconductor laser, the frequency is IMHz,
A repetitive signal with a recording pulse width of 500 ns was generated at 900 r p
Writing was performed by changing the power under the conditions of m, and the pulse width of the reproduced signal with the smallest jitter was measured under the read power of 1i. Further, the reflectance of this disk after being left at 60° C. and 90% R)I for 200 hours and 500 hours was measured to examine changes from the initial state. .

The results are shown in Table 1.

Example 2 A 20 nm thick film of alkali-free glass was formed by RF sputtering on a φ130 decorative polycarbonate resin disc substrate with circular grooves, and then an amorphous film made of Te and Bi was formed by DC sputtering. (Composition Te:
Bi=75:25 (atomic ratio)) was formed into a film with a thickness of 40 nm, and finally, alkali-free glass was formed into a film with a thickness of 40 nm by RF sputtering.

The wavelength 8
Frequency IMHz using 30 ni semiconductor laser,
A repetitive signal with a recording pulse width of 500 ns was written at 900 rpm while changing the power, and the pulse width of the reproduced signal with the smallest jitter was measured at a read power of 1 mW. Further, the reflectance of this disk after being left for 200 hours and 500 hours under the condition of 60''C990%RH was measured to examine changes from the initial state.

The results are shown in Table 1.

Example 3 Te was deposited on a φ130 am polycarbonate resin spiral grooved disk substrate by DC sputtering.

A microcrystalline film consisting of Se and Ti (composition Te: S
e:Ti=92:7:1 (atomic ratio)) to 40
A Ti film was formed to a thickness of nm, and then Ti was deposited by RF sputtering.
A film of 30 nm thick was formed.

The wavelength 8
Frequency IM11z+ using 30nm semiconductor laser
A repetitive signal with a recording pulse width of 500 ns was written at 900 rpm while changing the power, and the pulse width of the reproduced signal with the smallest jitter was measured at a read power of 1 mW. Further, the reflectance of this disk after being left for 200 hours and 500 hours under conditions of 60'C and 90% RH was measured to examine changes from the initial state.

The results are shown in Table 1.

Comparative Example 1 Te was deposited on a polycarbonate resin spiral grooved disk substrate of φ130 mm by DC sputtering.

Microcrystalline film made of Se (composition is the same as in Example 1)
was formed into a film with a thickness of 40 nm.

The wavelength 8
Using a 30n+w semiconductor laser, the frequency is IMHz,
A repetitive signal with a recording pulse width of 500 ns was recorded at 900 rpm+
Writing was performed by changing the power under the following conditions, and the pulse width of the reproduced signal with the smallest jitter was measured at a read power of 1 mW. Further, the reflectance of this disk after being left for 200 hours and 500 hours under conditions of 60'C and 90% RH was measured to examine changes from the initial state.

The results are shown in Table 1.

Comparative Example 2 Te was deposited on a polycarbonate resin spiral grooved disk substrate having a diameter of 130 mm by DCC sputtering.

Amorphous film made of Bi (composition is the same as Example 2)
was formed into a film with a thickness of 40 nm.

The wavelength 8
Frequency IMHz + using 30nm semiconductor laser
A repetitive signal with a recording pulse width of 500 ns was written at 900 rpm while changing the power, and the pulse width of the reproduced signal with the smallest jitter was measured at a read power of 1 mW. Further, the reflectance of this disk after being left for 200 hours and 500 hours under conditions of 60''C and 90% RH was measured to examine changes from the initial state.

The results are shown in Table 1.

Comparative Example 3 Te was deposited on a φ130 mm polycarbonate resin disk substrate with spiral grooves by DCC sputtering.

A microcrystalline film (composition is the same as in Example 3) made of Se and Tf was formed to a thickness of 40 nm.

The wavelength 8
Frequency IMHz using 30r+n+ semiconductor laser
, a repetitive signal with a recording pulse width of 500 ns, 900 rpm
Writing was performed by changing the power under the conditions of m, and the pulse width of the reproduced signal with the smallest jitter was measured under the read power of ld. In addition, this disk was heated at 60'C, 90%R)I(
7) After being left for 20 hours and 500 hours under the same conditions, the reflectance was measured and changes from the initial state were investigated.

The results are shown in Table 1.

It was confirmed that the pulse width of the reproduced signal was approximately the same as the recording pulse width.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the optical information recording medium of the invention, and FIG. 2 is a sectional view showing another embodiment of the optical information recording medium of the invention. 1: 5 plate, 2: reflective film, 3: inorganic oxide film [Effects of the invention]

Claims (1)

[Claims] 1. An optical information recording medium that records information by forming convex portions upon receiving a recording beam, which includes a substrate and Te formed directly on the substrate or via an inorganic oxide film. A reflective film in a microcrystalline state or an amorphous state as a main component,
An optical information recording medium comprising an inorganic oxide film provided on the reflective film. 2. The inorganic oxide film is glass, SiO_2, SiO,
TiO_2, Y_2O_3, Al_2O_3, ZnO,
The optical information recording medium according to claim 1, which is a thin film selected from B_2O_3, ZrO_2, GeO_2, or a composite thereof. 3. The optical information recording medium according to claim 1 or 2, wherein the thickness of the inorganic oxide film is 5 nm or more and 200 nm or less. 4. The optical information recording medium according to claim 1, wherein the reflective film has a thickness of 10 nm or more and 100 nm or less. 5. The optical information recording medium according to claim 1, wherein the substrate material is a transparent plastic material selected from the group consisting of polycarbonate resin, polymethyl methacrylate resin, epoxy resin, and amorphous polyolefin, or glass.