JPH02201746A - Optical recording medium - Google Patents

Abstract

PURPOSE:To simplify system constitution by constituting an additionally recordable recording layer and a rewritable recording layer on the same surface of a substrate. CONSTITUTION:The additionally recordable optical recording layer and the rewritable optical recording layer are formed on one substrate. Information is recorded on the rewritable optical recording layer at the time of recording the information which is merely temporarily needed on one of the two optical recording layers. The information is recorded on the additionally recordable optical recording layer at the time of permanently recording the information. Reading out is, of course, possible from both the optical recording layers. The recording of the information desired to be permanently preserved and the information desired to be temporarily recorded is executed by using one optical recording medium. The system constitution is simplified in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical recording medium having at the same time a temporary storage optical recording layer and a permanent storage optical recording layer.

BACKGROUND OF THE INVENTION Regarding optical recording media, first, an optical recording medium (so-called write-once) on which information cannot be rewritten and which can be additionally recorded was developed, and subsequently, an optical recording medium on which information can be rewritten has been developed. However, there has never been an optical recording medium that has these two functions at the same time.

Therefore, rewritable optical recording media have been used to record information that is only needed temporarily and information that is permanently needed on one optical recording medium.

Problems to be Solved by the Invention However, with the above configuration, when information is being recorded, it is in a rewritable mode, so there is a risk of disturbing permanently necessary information. To avoid this, if the optical recording medium is mechanically or electrically protected, no information will be recorded at all.

If you want to write by force, you have to cancel the above-mentioned mechanical or electrical signal protection, but if you do so, there is a risk that the information content may be changed without permission.

In order to eliminate this drawback, a complicated system was required in which separate optical recording media were arranged in separate drives and used for different purposes.

The present invention records information that is only needed temporarily and information that is desired to be stored permanently using one drive, that is, one optical recording medium.

Means for Solving the Problems The optical recording medium of the present invention has a rewritable optical recording layer and an additional recordable optical recording layer formed on one substrate.

Function The optical recording medium of the present invention has two optical recording layers, -
When recording information that is only needed temporarily, the information is recorded on a rewritable optical recording layer. Furthermore, when information is to be permanently recorded, it is recorded on an optical recording layer that allows additional recording. Of course, reading is possible from any optical recording layer. Therefore, it is possible to record information that is desired to be stored permanently and information that is desired to be recorded temporarily using one optical recording medium.

Example Examples of the present invention will be described below.

Example 1 An additionally recordable optical recording layer (thickness: 0.3 μm) made of N Te Ox on a substrate, and a separation layer (thickness: 0.5 μm) made of a polymer on top of that, and a separation layer made of a spiropyran compound on top of that. Rewritable optical recording layer (film thickness 0.
3 μm), and finally, a protective layer is sequentially provided thereon to produce an optical recording medium.

The above-mentioned optical recording medium can be selected in advance between an additionally recordable recording mode and a rewritable recording mode, but is usually set to the rewritable mode. Information is recorded on the rewritable recording layer provided on the upper layer of the optical recording medium by repeating recording and erasing using a semiconductor laser having a wavelength Ei of 80 nm in the same manner as in a normal method. If this information can be updated, keep it as is. If it is a problem that this information is not disturbed, the recording mode is set to enable additional recording, and a semiconductor laser with a wavelength of 800 nm is used to write on the additional recording layer provided at the bottom of the optical recording medium. Since the rewritable recording layer made of a spiropyran compound is transparent to the semiconductor laser,
Information can be written to the additionally recordable recording layer formed below without any influence. Therefore, once written information is not disturbed.

As in this embodiment, when the additionally recordable recording layer and the rewritable recording layer are configured on the same surface of the substrate, there is an advantage that the system configuration is simplified.

Example 2 An additional recordable optical recording layer made of PbTeSe and configured in an air sandwich type was provided on the substrate, and Pb
An optical recording medium is prepared by providing a rewritable optical recording layer made of a Ge5bTe compound in a contact type on a substrate opposite to that on which the optical recording layer made of TeSe is provided.

Since both of the above optical recording layers are sensitive to semiconductor lasers of the same wavelength (800 nm), recording and erasure are performed from different sides of the substrate. Therefore, in the rewritable mode, the recording layer made of Ge5bTe compound has a wavelength of 800 nm.
Recording and erasing is performed using a semiconductor laser, and in additional recording mode, Pb
Recording and erasing is performed on the recording layer made of TeSe from the side opposite to the recording layer made of the Ge5bTe compound using a semiconductor laser with a wavelength of 800 nm.

This embodiment has the advantage that only one semiconductor laser is required, unlike the first embodiment.

Example 3 As in Example 1, an additionally recordable optical recording layer and a rewritable optical recording layer are formed on the same surface of a substrate.

On the substrate, an additional recordable optical recording layer (thickness 200) made of spiropyran compound 1 shown below, a separation layer (thickness 75) on top of that, and a rewritable optical recording layer made of spiropyran compound 2 shown below. (film thickness: 100) are sequentially provided to create an optical recording medium. In this example, the wavelength is 480
Recording and erasing is performed using semiconductor lasers of nm and Ili 20 nm.

In this example, the total film thickness of the recording layer and separation layer is 0.
．． Since it is extremely thin at 0.375 μm, it has the advantage that focusing of a semiconductor laser light source is unnecessary.

(Hereinafter, blank space) C0OH Spiropyranhi 1 -O As shown in FIG.

Further, the recording material used for the rewritable optical recording layer and the additionally recordable optical recording layer may be an organic material or an inorganic material.

Effects of the Invention According to the present invention, in an optical recording medium in which a rewritable recording layer and an additionally recordable recording layer are formed on one substrate,
The effect is great because it is possible to easily use one optical recording medium to store information that is to be stored permanently and information that is to be stored temporarily without having to protect it mechanically or electrically. be.

Name of agent: Patent attorney Shigetaka Awano Haka 1 person H Spiropyran 1SA2

Claims (3)

[Claims] (1) An optical recording medium in which a rewritable optical recording layer and an additional recordable optical recording layer are formed on one substrate. (2) The optical recording medium according to claim 1, wherein a rewritable optical recording layer and an additionally recordable optical recording layer are formed on the same surface of one substrate. (3) The optical recording medium according to claim 1, wherein a rewritable optical recording layer and an additionally recordable optical recording layer are formed on one substrate on opposite sides of the substrate.