JPH0335446A - Rewritable type optical disk having immobilizable part - Google Patents

Abstract

PURPOSE:To stably pressure data over a long period of time by providing a reflecting layer consisting of a 2nd recording layer which allows write once recording with the laser power higher than an ordinary laser power on a recording layer to provide an irreversible recording state. CONSTITUTION:A recording medium 2 which is the 1st recording layer and the reflecting film 3 which is the 2nd recording layer are successively provided on a substrate 1. A phase changing material or magneto-optical material is used for the recording layer 2 and a write once optical disk medium material, such as TeOx, is used for the reflecting film 3. The ordinary reversible recording is executed by utilizing the phase change or magneto-optical effect of the recording medium and the immobilization is executed by executing the write-once recording, such as hole opening, on the reflecting film 3 by executing the recording with the laser power higher than the usual laser power. The signal recording immobilized in the prescribed part only by the change in the quantity of the reflected light is thus executed. The recorded information is easily immobilized in this way and the preservation of the data stably over a long period of time is possible.

Description

[Detailed Description of the Invention] [Summary] Regarding a rewritable optical disc having a fixable part, an object of the present invention is to provide a rewritable optical disc having a fixable part that can stably store data for a long period of time. In an optical disc that is composed of a substrate and a recording layer formed on the substrate and records signals by reversibly changing its optical characteristics, write-once recording is performed on the recording layer using a laser power higher than usual. The recording state is made irreversible by providing a reflective layer consisting of a possible second recording layer.

[Industrial application field]

The present invention relates to a rewritable optical disc having a fixable portion.

At present, read-only memo 'J-(ROM)' or optical discs with -times writing have been put into practical use, and rewritable optical discs are being researched. In order to protect or semi-permanently preserve recorded data on this rewritable optical disc, it is necessary to fix a part or the entire surface of the optical disc.

[Conventional technology]

Conventionally, rewritable optical discs cannot be fixed as they are, and a read-only optical disc has to be created by creating a stamper from the data to be fixed, or the data has not been fixed.

[Problem to be solved by the invention]

Therefore, there has been a drawback that the rewritable optical disc cannot be easily fixed. Further, there is a problem in the long-term stability of the medium or the writing state, and there is a problem that data cannot be stored stably for a long period of time.

An object of the present invention is to provide a rewritable optical disc having a fixable portion capable of stably storing data for a long period of time.

[Means to solve the problem]

According to the present invention, the above-mentioned problem is solved in an optical disc comprising a substrate and a recording layer formed on the substrate, in which signals are recorded by reversibly changing optical characteristics. The problem is solved by a rewritable optical disc having a fixable portion, which is characterized by providing a reflective layer consisting of a second recording layer capable of write-once recording using laser power to make the recording state irreversible.

[For production]

In the present invention, a second recording layer is added on the main structure of the conventional substrate and recording layer (first recording layer) with a laser power of higher than usual, for example, 15 to 2
Optical disc media materials that can be used for write-once recording at 0 mW, such as InSb (Sb64atomi)
c%> etc. is provided.

In this way, in the present invention, the second recording layer is provided on the first recording layer, and since a material that cannot be written with normal laser power is used, recording can be fixed by changing the amount of reflected light ( so-called "tampering") is done.

The present invention can be used for optical disks and magneto-optical disks (both are simply referred to as optical disks in this application).

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a sectional view showing the principle of the present invention.

In FIG. 1, a recording medium 2 as a first recording layer and a reflective film 3 as a second recording layer are sequentially provided on a substrate 1.

The recording medium 2 is a phase change material or a magneto-optical material. The reflective film 3 is made of a write-once optical disk medium material such as TeOx. Typical reversible recording utilizes phase changes or magneto-optical effects in the recording medium. When fixing, recording is performed with a laser power higher than usual to perform write-once recording such as drilling holes in the reflective film 3, and by changing the amount of reflected light, a signal is recorded with only a predetermined portion fixed.

FIG. 2 is a sectional view for explaining one embodiment of the present invention.

In Fig. 2, (BiY)z(FeGa)sO+z with a thickness of 3Q nm is deposited on a garnet substrate 11 by sputtering.
Garnet recording film 12.1100n thick InSb
(Sb64at%) reflective films 13 are sequentially formed.

The garnet recording film 12 is transparent and has a magneto-optical effect.

Further, the In5b (Sb64at%) reflective film 13 becomes a write-once medium using a phase change phenomenon.

An argon laser was used to write signals in this example.

In the reversible recording, a signal was recorded with a power of 10 mvI at a disk rotation speed of 180 rpm, and the rotation angle of the polarization plane at this time was about 3 degrees in a round trip.

By writing a signal at 1800 rpm and 18 mW on this medium, a phase transformation occurred in the InSb medium which was used as a reflective film, and it was possible to fix the medium. The difference in reflectance due to this phase change is
There are approximately 15%.

FIG. 3 is a sectional view for explaining another embodiment of the present invention.

A 200 m thick InSb (Sb 60 at%) recording medium layer 22, which allows reversible recording by sputtering on a glass substrate 21. A 240 nm thick Si port and an interference layer 24.
．． 1100n thick write-once InSb (Sb
64 at %) recording medium layers 23 are sequentially formed. A semiconductor laser (wavelength g3Qnm) was used to write signals on this recording medium. In this example, the rotation speed is 30 Orp.
InSb (Sb60a
t%) reversible recording of the medium was possible. When a signal is written to this medium at 15 mW, the reflective layer InSb (Sb
64at%) The medium undergoes phase transformation and a signal can be recorded. Then 3. QmW irradiation was performed, and InSb (Sb6
(0at%) Immobilization can be performed by aligning the medium to an erased state.

In the part where this fixation has been performed, even if a recording is made by mistake during a normal recording operation with low power, it will not affect the InSb recording medium layer 23, so it is only necessary to erase the 1nsb recording medium layer 22. . The 5102 interference layer is transparent and acts as a buffer to prevent reaction of the InSb above and below.

〔Effect of the invention〕

As explained above, according to the present invention, by recording on a reflective film in a rewritable phase change optical disk that can be erased and rewritten, recorded information can be easily fixed, and stable data can be maintained over a long period of time. It is now possible to save. Furthermore, a rewritable area and a fixed area can easily coexist on the same optical disc.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the principle of the present invention, Fig. 2 is a sectional view illustrating one embodiment of the invention, and Fig. 3 is a sectional view illustrating another embodiment of the invention. FIG. 1... Substrate, 2... Recording medium, 3...
... Reflective film, 11... Garnet substrate,
12... Garnet recording film, 13... InSb reflective film, 21... Glass substrate, 22.23... InSb recording medium layer, 24... 5in2 interference layer.

Claims (1)

[Claims] 1. An optical disc comprising a substrate and a recording layer formed on the substrate, in which signals are recorded by reversibly changing optical characteristics, wherein a laser beam with a higher than usual power is placed on the recording layer. 1. A rewritable optical disc having a fixable portion, characterized in that a reflective layer consisting of a second recording layer capable of write-once recording with power is provided to make the recorded state irreversible.