JP2993973B2 - Optical information recording medium - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical information recording medium in which information is recorded and reproduced by irradiating a disk having a thin film formed on a substrate with a pulse of a light beam. .

[Conventional technology]

The phase change recording material is an optical information recording material that changes the phase of a thin film from non-crystalline to crystalline by laser beam irradiation and records information by changing its reflectivity. There is.

[Problems to be solved by the invention]

The optical information recording medium is attracting attention as a high-density information recording medium, but as the density increases, the distance between the pits decreases and the size of the pits increases due to the effect of the heat that recorded the pits before and after. I will. Due to the influence of the thermal diffusion, not only does the duty of the recording signal change, but also the reflectance of the portion of the pit that is not irradiated with the laser beam increases, making it difficult to read the signal accurately.

[Means for solving the problem]

The recording layer in the present invention contains GeTe as an essential element,
A phase change recording material containing at least one element from among Sn, Cr, Se, Au, and Cr, and containing a fluororesin (for example, polytetrafluoroethylene) as an additional substance.

[Operation] In the present invention, as a means for preventing the influence of thermal diffusion during recording, a fluorine resin is added to a GeTe-based material to lower the thermal conductivity of a recording film, and the heat generated by a laser beam It becomes difficult to transmit to parts other than the irradiated part, and the influence of thermal diffusion is reduced.

When the thermal conductivity is low, it becomes difficult for heat to escape from the pits to other parts, so not only can the pits be prevented from spreading, but also the sensitivity of the recording film is improved, and by including a fluororesin in the recording film There is an advantage that the moisture resistance of the film is improved and the recording life of the recording film can be maintained long.

〔Example〕

FIG. 1 shows an embodiment of the optical information recording medium according to the present invention. The substrate 1 is a polycarbonate substrate and has a thin film obtained by adding a fluorine resin to GeTeSnCuSe as an optical recording film 2 thereon. Further, in order to prevent dust and mechanical damage on the recording film, an ultraviolet curable resin layer was laminated as a protective film 3. Here, the substrate 1 is not limited to polycarbonate, but may be a PMMA, polyolefin, or glass substrate.

The optical recording film 2 is produced by a dual simultaneous sputtering method. After evacuation of the vacuum chamber of the sputtering apparatus to about 5 × 10 ^-4 Pa, an inert gas such as Ar was introduced to reduce the gas pressure to 5 to 9
× 10 ^-1 Pa. Here, claim 1
When a high frequency power is simultaneously applied to the alloy target and the fluororesin target for producing the recording film described in the above item, the optical recording film can be formed on the substrate by the sputtering action.

As shown in FIG. 2, the formed recording film is GeTeSnCuSe
Fluororesins 22 are scattered as fine particles in the thin film 21, and the thermal conductivity is low, so that the influence of thermal diffusion of the irradiated laser beam can be reduced. Further, the protective layer made of a fluororesin can be stacked by performing the binary sputtering with the recording film 2 formed integrally.

FIG. 3 shows the recording of a single frequency and the measurement of the duty ratio of the pits of the reproduced signal. In a recording film to which no fluorine is added, the pits expand as the frequency increases. However, it shows that pits faithful to the input signal can be recorded from the low frequency to the high frequency on the fluorine-added disk.

〔The invention's effect〕

In the high information recording medium according to the present invention, since the recording film is doped with the fluororesin, the pits do not spread due to the influence of heat diffusion, and even if the distance between the pits is reduced, the pits faithful to the input signal are formed. Can be recorded.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of the present invention, FIG. 2 is a view showing the existence of a fluororesin in a recording film, and FIG. 3 is a view showing the spread of recording pits. 1 ... substrate 2 ... recording film 3 ... protective film.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41M 5/26

Claims (1)

(57) [Claims] 1. An optical information recording medium for recording information by irradiating a thin film formed on a substrate with a light beam to record information, wherein said thin film contains Ge and Te as essential elements, and said thin film contains fine particles of fluororesin. An optical information recording medium, wherein the optical information recording medium is dispersed in a state of being scattered.