JPH09180257A - Optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the track access time and to rapidly and stably recording/ reproduce information in a large volume by sticking to each other two pieces of optical disks capable of inter-layer movement processing a focal point of a light beam in the process regenerating a ROM layer and recording on a RAM layer. SOLUTION: The information is reproduced by focusing the light beam 206 on the track of the ROM layer 202. Further, the information is recorded/erased on/from the RAM layer by focusing the light beam 206 on the RAM layer 203 through the ROM layer 202 and an intermediate layer 204. Further, the information is reproduced by detecting an optical signal from the reflected light beam returning through the intermediate layer 204 and the ROM layer 202. When the light beam 206 is written in the RAM layer 203 in the process processing a regenerative signal on the track of the ROM layer 202, the focal point of the light beam 206 is subjected to inter-layer movement processing and recorded on the RAM layer 203 existing in the same radius. Similarly, by sticking to each other the optical disk 201'-205' and making them a piece of optical disk, a large volume is obtained. Thus, the track access time is shortened, and the information is recorded/reproduced, rapidly and stably in a large volume.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc, and more particularly, to an optical disc having at least two or more layers capable of reading out a signal by irradiating a light beam in a direction perpendicular to a light beam incident surface. The present invention relates to a partial ROM disk in which a RAM section capable of recording / reproducing / erasing an information signal and a ROM section capable of only reproducing are provided on the optical disk.

[0002]

2. Description of the Related Art In recent years, RAM capable of recording / reproducing and erasing signals
A so-called partial ROM disc, which has a read-only portion, and a ROM portion in which a signal is recorded in advance and which can only read the signal, has been proposed and is generally used. According to Japanese Industrial Standard JIS X 6272 “90 mm rewritable and read-only optical disk cartridge”, the partially embossed disk corresponds to the partial ROM disk. (The international standard is ISO / IEC
Corresponding to 10090. In a conventional partial ROM disc, the information track of the RAM section is arranged on the inner peripheral side of the ROM as shown in FIG.
It is known that some information tracks have a structure in which they are located on the same layer on the outer peripheral side (for example, Japanese Patent Publication No.
(See Japanese Patent Publication No. 59494). In the figure, 901 is a partially embossed disk, 902 is a RAM section, that is, an area having an information track capable of recording / reproducing information signals, and 903 is R.
An OM portion, that is, an area having a track in which information is recorded and which can only be reproduced is shown. A partial radial cross-section of such a disc is shown in FIG. 1001 is polycarbonate (PC) or polymethylmethacrylate (PMM)
A transparent substrate made of a transparent resin such as A), 1002 R having an information track capable of recording / reproducing an information signal
An AM section, 1003 is a ROM section having a pre-recordable and read-only track, and 1004 is a protective layer.

Further, as shown in FIG. 11, a RAM disk having a RAM section capable of recording a signal and a ROM disk having a ROM section to which a signal is previously fixed are fitted through a hollow portion, and 1 There is an optical disc having a structure of one disc (for example, Japanese Patent Publication No. 44106/1993). In FIG. 11, reference numeral 1101 denotes a substantially transparent ROM disk having concave and convex pits with a reflectance of 3 to 4%, 1102 a RAM disk having a recording film 1104 containing Te, for example, and 1103 a hollow portion. The surfaces of the ROM disk 1101 and the RAM disk 1102 on which the information signals are recorded are opposed to each other, and the ROM disk and the RAM disk are connected to each other at the outer periphery and the inner peripheral edge via a hollow portion 1103. The ROM disk and the RAM disk are detachably configured and can be combined with various disks according to the application.

Further, as a publicly known example which has been conventionally known, there is a multi-layer optical disc as shown in FIG. 12, in which two or more recording layers whose optical constants are changed by irradiation of a light beam are laminated. This is intended to improve the recording density.

[0005]

In the first known example among those described in the prior art, firstly, since the RAM portion and the ROM portion are provided on the same layer, one surface of the disc Storage capacity is RAM area or RO
Secondly, when the information relating to the information in the ROM portion is to be recorded in the RAM portion without going over the disk having the M portion, the track to the RAM portion at a position distant from the ROM portion in the radial direction is formed. There is a problem in that access is required and it takes time until a recordable state occurs due to this physical distance. This problem can be solved by using a linear motor for high-speed access in the optical disk recording / reproducing apparatus, but in that case, there is a problem that the apparatus becomes complicated and the cost becomes high.

In the second known example of the prior art, since the ROM part and the RAM part are manufactured separately, the structure is different from that of the present invention in that the structure is not multi-layered and complicated. However, the ROM disk and the R disk have a high manufacturing cost, and the ROM disk and the RAM disk are detachable.
When replacing the AM disk, there is a problem that dust may be mixed into the hollow portion.

In the third known example of the prior art, a multi-layered structure is used only for the purpose of improving the recording density, and a partial ROM disk using a RAM part and a ROM part together is used. It is needless to say that no means for solving the above-mentioned problem that track access from the ROM section to the RAM section takes time is not provided.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is to reduce the storage capacity of the disk and to provide a RAM portion for recording signals. The present invention intends to provide an optical disc that shortens the time for which data can be recorded, eliminates the possibility of dust and the like entering between layers of each RAM and ROM, and enables large-capacity high-speed stable recording / reproducing / erasing of signals. It is a thing.

[0009]

In order to achieve the above object, an optical disk according to the present invention has a plurality of layers (ROM layer or RAM layer) from which a signal can be read by irradiating a light beam, A multi-layer disc having a multi-layer structure in which at least one layer is a recordable / rewritable layer (RAM layer) and the other layer is a read-only layer (ROM layer); It is configured by laminating a single-layer or multi-layer optical disc.

Then, a layer (R
As for the AM layer), since the energy of the light beam must be strong when recording and erasing the signal, the layer capable of recording / reproducing / erasing is a layer in which at least two or more layers are arranged in the direction perpendicular to the light beam incident surface. Of these, it is preferable to be provided at a position closest to the surface on which the light beam is incident.

The recording / reproducing erasable layer has a phase in which a crystalline state and an amorphous state undergo a reversible phase change due to heating or cooling, thereby changing an optical constant and recording or erasing information. A changing film can also be used.

When the phase change film as described above is used for the recording / reproducing / erasable layer, the recording / reproducing / erasable layer is previously formed on the entire surface of the layer for the reason described later.
It is desirable to record the signal. The information content of the signal may or may not have meaning.

Further, the layer capable of recording / reproducing / erasing a signal is
The magneto-optical film may be configured to change the optical characteristics by setting the direction of the magnetic poles upward or downward to enable recording / reproducing / erasing of signals.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a partial radial cross-sectional view of an optical disc according to an embodiment of the present invention, which particularly corresponds to claim 1 and others claim 7, claim 8, and claim 15. In the figure, 101 is polycarbonate (PC) or polymethylmethacrylate (PMM).
A transparent substrate made of a transparent resin such as A). It should be noted that on the surface of the transparent substrate 101 on the 102 side, fine information pits having a shape for expressing an information signal are formed in advance by molding. 102 is formed on the information pit. Reference numeral 102 denotes a ROM layer made of a thin film such as aluminum or gold that can only reproduce a signal, and is formed by sputtering or vapor deposition. Furthermore that R
104 is formed on the OM layer 102. 104 is RO
An intermediate layer for separating and adhering the M layer 102 and a RAM layer 103, which will be described later, from a transparent member having a high light beam transmittance and having a thickness of about 40 μm. An example of the transparent member in this case is an ultraviolet curable resin. For example, an ultraviolet curable adhesive model number KZ8611J made by Japan Synthetic Rubber (in the case of a light beam having a wavelength of 650 nm, its transmittance is 99% or more). .) Is used. Then, 103 is formed on the intermediate layer 104. 103
Is a RAM composed of a recording film capable of recording / reproducing signals
It is a layer. The RAM layer 103 and the ROM layer 102 described above
The thickness of each of the layers is very small.
It is an order. In addition, the ROM layer 102 and the RAM described above
The layer 103 and the intermediate layer 104 are formed over the entire effective surface of the optical disc. Or RAM
A ROM portion in which ROM data by information pits is recorded in advance may be provided in a part of the layer 103 to form a partial RAM layer. It should be noted that if a guide groove for guiding the light beam to a predetermined position is formed on the surface of the intermediate layer 104 provided with the RAM layer 103 at the time of recording / reproducing / erasing the information signal. Is the intermediate layer 104
The surface of the stamper in which the shape of the groove is engraved is formed by the 2P (photopolymer) method on the RAM layer 103.
Is formed on the ROM layer 102 by using a photopolymer having a groove formed by being transferred to a surface on which is mounted. After the RAM layer 103 is formed, finally, RA
105 is formed on the M layer 103. A protective layer 105 is made of the same ultraviolet curable resin as that of the intermediate layer 104. As above, each layer is laminated,
The thickness of each layer is designed so as to form a multilayer disc having a layered structure and a thickness of about 0.6 mm.
Then, as shown in FIG. 1, two such multilayer discs (A-side disc and B-side disc) are laminated so that the protective layers face each other, and in the optical disc of the present invention, the total disc thickness is Is about 1.2 mm. In the bonding at that time, for example, the two multi-layer disks are bonded by a method using an ultraviolet curable resin or an adhesive sheet or a bonding method by a hot melt method. It should be noted that the reference numerals shown in the drawings attached to the laminated multilayer disc (B side disc) having the same structure as the laminated multilayer disc (A side disc) are 101 and 101 ′. , 102 and 102 ′, 103 and 103 ′, etc. indicate that they are similar to each other. In the following specification, drawings, and abstract, unless otherwise stated, the description regarding 101 and the like is
The same applies to 101 'and the like.

Reference numeral 106 denotes a light beam, which is the substrate 10
It is irradiated from the 1 side. When the signal is reproduced by the ROM layer 102, the light beam 106 is emitted from the ROM layer 102.
Controlled to focus on. In addition, the RAM layer 10
When recording, reproducing, or erasing a signal in 3, the light beam 106 is controlled so as to focus on the RAM layer 103. The same applies to the case where the light beam 106 'is irradiated from the substrate 101' side, but when the signal is reproduced by the ROM layer 102 ', the light beam 106' is emitted from the ROM layer 102 '. The light beam 10 is controlled to focus on, and when recording, reproducing, or erasing a signal in the RAM layer 103 '.
6'is controlled to focus on the RAM layer 103 '. Although FIG. 1 shows an embodiment in which two light beams 106 and 106 ′ are used, for example, while recording and reproducing a signal with two light beams from the substrate 101 side, There may be a case where two or more light beams are used at the same time, for example, a signal is reproduced with one light beam from the substrate 101 ′ side.

By adhering two such multi-layered discs together, the storage capacity of the optical disc can be further increased, and the light beam 106 and the light beam 106 'can be provided from both sides of the optical disc. It is possible to irradiate, for example, simultaneous reproduction of information signals by two light beams on both sides of the optical disc, and high-speed switching of read / write operations for instantaneously writing data related to signals read from one side of the optical disc to the other side. It is possible to improve efficiency.

FIG. 2 shows the RA of the optical disc of FIG.
FIG. 6 is a diagram showing a light beam irradiation state when recording, reproducing, or erasing a signal in the M layer 103 and when reproducing a signal by the ROM layer 102. The state of FIG. 2A shows the case of reproducing the ROM layer, and the state of FIG. 2B shows the case of recording, reproducing or erasing on the RAM layer. In the figure, 201 is a substrate, 202 is a ROM layer, 203 is a RAM layer, 204 is an intermediate layer, 205 is a protective layer, and 206 is a light beam, and the features of the respective constituent elements are the same as in the case of FIG.

The reproduction of the signal by the ROM layer is shown in FIG.
As shown in FIG. 3, by focusing the light beam 206 on the information track of the ROM layer 202 and reproducing the modulated data obtained from the information pits formed on the information track of the ROM layer 202, Reproduce the information signal. In addition, recording / erasing or reproducing to / from the RAM layer is performed as shown in FIG.
As shown in (b), the light beam 206 is focused on the information track of the RAM layer 203 via the ROM layer 202 and the intermediate layer 204. When reproducing from the RAM layer 203, the light beam focused on the RAM layer is reflected,
This is performed by detecting an optical signal returning via the intermediate layer 204 and the ROM layer 202.

The light beam 206 is emitted from the ROM layer 2 of FIG.
In the process of reproducing the information track No. 02 and processing the data of the reproduced signal, when the related data is recorded in the RAM layer 203, the focus of the light beam 206 is moved between layers, and In this state, the information is recorded on the information track on the RAM layer 203 located at the substantially same radius of the ROM layer 202. By performing such processing, the moving distance of the light beam can be set to several tens of μm at most, and the track access between the information track of the ROM layer and the information track of the related RAM layer can be performed in a short time. . And
In this case, it is not necessary to use a linear motor for high speed access as in a conventional partial ROM disc having a ROM section and a RAM section in the same plane.

As a method of using the RAM layer, the data related to the data of the reproduction signal from the information track of the ROM layer as described above is placed at substantially the same radius of the ROM layer.
In addition to recording in the information track of the AM layer, the versioned data can be stored in the RAM layer when the computer software is upgraded.

FIG. 3 shows the invention, in particular claim 10 and claim 11 and additionally claim 1, claim 2 and claim 15.
FIG. 6 is a partial cross-sectional view in the radial direction of the optical disc according to the embodiment corresponding to FIG. In the figure, 301 is a transparent substrate made of a transparent resin capable of transmitting a light beam, 302 is a RAM layer composed of a recording film capable of recording / reproducing signals, and 303 is a first ROM layer capable of only reproducing signals, 304 Is the RAM layer 30
2 is a first intermediate layer separating the first ROM layer 303 from the second ROM layer, and 305 is a second ROM layer capable of reproducing only a signal, 3
Reference numeral 06 is a second intermediate layer that separates the first ROM layer 303 from the second ROM layer 305, 307 is a third ROM layer that can only reproduce signals, and 308 is a second ROM layer 305.
Is a third intermediate layer for isolating the third ROM layer 307 and 309 is a protective layer. 310 is a light beam,
Irradiation is performed from the substrate 301 side.

An example of a method of manufacturing the optical disc shown in FIG. 3 will be described below. First, the transparent substrate 301 is made of a transparent resin such as polycarbonate (PC) or polymethylmethacrylate (PMMA). If the above-mentioned guide groove (groove) is formed on the transparent substrate 301 by RA
When it is formed on the surface of the M layer 302 side, it is formed in advance by molding. A RAM layer 302 is formed on the surface of the transparent substrate 301. Then, the RAM layer 3
02, using the 2P (photopolymer) method described above,
An intermediate layer 304 made of photopolymer having fine information pits formed is formed on the ROM layer 303 side. Then, the ROM layer 303 is formed on the intermediate layer 304. Further, on the ROM layer 303, an intermediate layer 306 formed by the 2P (photopolymer) method similar to the intermediate layer 304 is formed. And RO on the middle layer 306
The M layer 305 is formed. Further, similarly, the intermediate layer 308 and the ROM layer 307 are formed. Finally, the ROM layer 30
A protective layer 309 made of an ultraviolet curable resin is formed on the substrate 7. The intermediate layers 304, 306, and 308 described above are used.
Is manufactured to a thickness of about 40 μm. Also, ROM
The layers 303, 305, and 307 are made of thin films such as aluminum and gold, and are manufactured by sputtering or vapor deposition. RAM layer 302 and 303, 305, 307
The thickness of each ROM layer is extremely small and is on the order of nm. Each layer is laminated as described above, and the layered structure has a thickness of about 0.6 mm.
Is configured to form a multi-layer disc. And
Two such multi-layer discs are laminated in the same manner as in FIG. 1 so that the protective layers face each other to form the optical disc of the present invention. The total disc thickness is about 1.2 mm. Is designed to be. In the optical disc constructed in this way, the first, second and third
It becomes possible to record the information relating to the data reproduced from the information track on the ROM layer on the RAM layer 302 on substantially the same radius.

FIG. 4 is a partial radial cross-sectional view of an optical disk according to an embodiment of the present invention, particularly claim 2 and others corresponding to claim 1, claim 7, claim 9 and claim 15. Is. In the figure, 401 is a polycarbonate (PC).
It is a transparent substrate made of a transparent resin such as polymethylmethacrylate (PMMA). 40 of the transparent substrate 401
When forming the above-mentioned guide groove (groove) for guiding the light beam to a predetermined position at the time of recording / reproducing / erasing the information signal, the groove is formed in advance by molding. Such a transparent substrate 401
A RAM layer 402 composed of a recording film capable of recording / reproducing and erasing signals is formed on the top. 4 on the RAM layer 402
04 is formed. Reference numeral 404 denotes the RAM layer 402 and 4 described later.
03 is an intermediate layer for adhering and separating 03.
It is made of a photopolymer having fine information pits formed on the 403 side by the P (photopolymer) method. Middle layer 4
A ROM layer 403 is formed on 04. Finally, 405 is formed on the ROM layer 403. 40
A protective layer 5 is made of an ultraviolet curable resin. In addition, the above R
Each of the OM layer 403 and the RAM layer 402 has a very small thickness on the order of nm. The thickness of the intermediate layer 404 is about 40 μm. As described above, the respective layers are laminated to form a multi-layer structure to form a multi-layer disc having a thickness of about 0.6 mm. Two such multi-layer discs are processed in the same manner as in FIG.
The protective layers are attached so as to face each other, and the thickness of each layer is designed so that the total thickness of the disc is about 1.2 mm, and the optical disc of the present invention is configured. Of the layers arranged in the direction perpendicular to the light beam incident surface as shown in FIG. 4, by setting the position of the RAM layer at a position close to the light beam incident surface, the energy of the strong light beam is generally increased. It is possible to efficiently record information on the required information track of the RAM layer. The RA
The M layer 402, the ROM layer 403, and the intermediate layer 404 are formed over the entire effective surface of the optical disc. Alternatively, RO is previously formed with information pits in a part of the RAM layer 402.
A ROM section recording M data may be provided to form a partial RAM layer. A light beam 406 is emitted from the substrate 401 side. Recording and reproducing signals in the RAM layer 402,
Alternatively, when erasing, the light beam 406 is controlled to focus on the RAM layer 402. Also, ROM
When the signal is reproduced by the layer 403, the light beam 406 is controlled so as to focus on the ROM layer 403.

FIG. 5 shows the RA of the optical disc of FIG.
When recording, reproducing, or erasing a signal in the M layer,
It is a figure which shows the irradiation state of a light beam at the time of reproducing a signal by an OM layer. The state of FIG. 5A shows the case where the signal is reproduced by the ROM layer, and the state of FIG. 5B shows the case where the signal is recorded, reproduced, or erased in the RAM layer. In the figure, 501 is a substrate, 502 is a RAM layer, 503.
Is a ROM layer, 504 is an intermediate layer, 505 is a protective layer, 506
Is a light beam, and the characteristics of each component are the same as in the case of FIG.

The reproduction of the signal by the ROM layer is shown in FIG.
As shown in FIG. 7, the light beam 506 is focused on the information track of the ROM layer 503 through the RAM layer 502 and the intermediate layer 504, and reflected from the information pit formed on the information track of the ROM layer 503. The detected optical signal is detected via the intermediate layer 504 and the RAM layer 502, and the modulated data is reproduced to reproduce the information signal from the ROM layer 503. Further, recording / erasing or reproduction of a signal to / from the RAM layer is performed by focusing the light beam 506 on the information track of the RAM layer 502, as shown in FIG. 5B. RA
The reproduction of the signal from the M layer 502 is performed by detecting the optical signal that returns when the light beam focused on the RAM layer is reflected.

Of the layers arranged at least two or more in the direction perpendicular to the light beam incident surface, the recording / reproducing / erasable layer is
By providing the position closest to the light beam incident surface,
It is possible to accurately record a signal in a layer capable of recording / reproducing and erasing.

The light beam 506 is emitted from the ROM layer 5 of FIG.
In the process of reproducing the signal of the information track No. 03 and processing the data of this reproduced signal, the related data is recorded in the RAM layer 50.
In the case of recording to No. 2, the focal point of the light beam 506 is subjected to interlayer movement processing so as to be in the state of FIG. 5B, and recording is performed to the information track on the RAM layer 502 located at substantially the same radius of the ROM layer 503. By performing such processing, the moving distance of the light beam can be set to several tens of μm at most, and the track access between the information track of the ROM layer and the information track of the related RAM layer can be performed in a short time. .

As described above, among the layers arranged at least two or more in the direction perpendicular to the light beam incident surface, the recording / reproducing erasable layer is provided at the position closest to the light beam incident surface, thereby recording / reproducing / erasing. It is possible to efficiently record a signal on a possible layer.

FIG. 6 shows a radial direction of an optical disk according to an embodiment of the present invention, particularly claim 3 and others corresponding to claim 1, claim 2, claim 7, claim 9 and claim 15. FIG. In FIG. 6A, 601 is a substrate made of transparent resin such as polycarbonate or PMMA, 602 is a RAM layer capable of recording / reproducing and erasing signals, 6
Reference numeral 03 is a ROM layer capable of reproducing only signals, and 604 is a RAM
An intermediate layer that separates the layer 602 and the ROM layer 603;
Reference numeral 05 is a protective layer. The feature of this figure is that RAM
That is, the layer 602 is formed of a phase change film. This phase change film causes a reversible phase change between, for example, a crystalline state and an amorphous state by heating and cooling by irradiation of a light beam with output control, and changes optical constants such as reflectance. As a result, signals can be recorded and erased. When reading a signal, the output of the light beam is reduced to about 1/10 of that at the time of recording. When this phase change film is used as a RAM layer, the phase change film has a high CN ratio even when a light beam of a short wavelength is used, and a magnetic field required when a magneto-optical film or the like is used as a RAM layer. Since the generation device is not required, the structure of the optical disk recording / reproducing device can be simplified, and the operation of recording another signal in the RAM layer in which the signal is recorded is performed only by controlling the output of the light beam. It becomes possible to make it easy. The features of the other components are the same as those in the case of FIG. A light beam 606 is emitted from the substrate 601 side. When recording, reproducing, or erasing a signal in the RAM layer 602, the light beam 606 is used.
Are controlled to focus on the RAM layer 602. Further, when a signal is reproduced by the ROM layer 603,
The light beam 606 is controlled to focus on the ROM layer 603.

FIG. 6B shows an embodiment in which FIG. 6A is actually used. In FIG. 6B, a RAM layer 602 having a multi-layer structure is provided so that a protection layer 607 and a reflection layer 608 formed by sputtering or vapor deposition are provided on a single-layer RAM layer 602 so far, as shown in the drawing.
And layers. For example, ZnS—SiO 2 or the like is used for the protective layer 607, an aluminum alloy or the like is used for the reflective layer 608, and Ge 2 Sb 2 Te 5 or the like is used for the phase change film 602.

As described above, by using the phase change film as the recording / reproducing erasable layer, the CN ratio is high even when a short wavelength light beam is used, and a magneto-optical film or the like is used as the RAM layer. When used, a necessary magnetic field generator is not required, so that the structure of the optical disk recording / reproducing apparatus can be simplified and the RA in which a signal is recorded is used.
The operation of further recording a signal in the M layer can be easily performed only by controlling the output of the light beam.

Next, referring to FIG. 7 relating to claim 4,
The reproduction signal level from the ROM layer in the case of the embodiment shown in FIG. 6 will be described. The vertical axis of FIG. 7 represents the HF reproduction signal level reproduced from the ROM layer via the RAM layer, and the horizontal axis represents time. FIG. 7A shows an example of the ROM layer reproduction signal level when the information signal is recorded only on a part of the RAM layer. Further, FIG. 7B shows a ROM in which a random information signal is recorded in advance on the entire surface of the RAM layer.
An example of the layer reproduction signal level is shown. As shown in FIG. 7A, when the information signal is recorded only on a part of the RAM layer, the transmittance changes when passing through the RAM layer on which the information signal is recorded, and the ROM layer reproduction signal is generated. The level changes, which makes stable signal reproduction difficult. On the other hand, when an information signal is recorded on the entire surface of the RAM layer, as shown in FIG. 7B, the transmittance does not change and the ROM layer reproduction signal level does not change and is stable. Signal reproduction is possible. Therefore, as described in claim 4, in the optical disc shown in FIG. 6, when the optical disc is first used by a person who uses the optical disc for the first time, it is meaningless over the entire surface of the recordable / reproducible / erasable layer. Signal has already been recorded, in other words, before the information signal is reproduced or recorded / erased from the optical disc, the RAM is previously recorded.
Non-meaningless data in a layer, for example, a signal that becomes a pattern that repeats the minimum mark or an irregular and meaningless random signal is recorded on the entire surface of the RAM layer to record information in the RAM layer. Only when it becomes necessary to overwrite the previously recorded data. The meaningless data signal may be a data signal having meaningful information property, for example, when the RAM layer is used as a temporary ROM layer.

As described above, when the recording / reproducing / erasable layer is composed of the phase change film, the signal from the layer only capable of reproducing the signal by previously recording the signal on the entire surface of the layer. Can be detected stably and accurately.

FIG. 8 is a radial direction of an optical disk according to an embodiment of the present invention, particularly claim 6, and other embodiments corresponding to claim 1, claim 2, claim 7, claim 9, and claim 15. FIG. In the figure, 801 is a substrate made of transparent resin such as polycarbonate or PMMA, 802 is a RAM layer capable of recording / reproducing signals, 803 is a ROM layer capable of only reproducing signals, and 804 is a RAM layer 802 and ROM.
An intermediate layer that separates the layer 803, and 805 is a protective layer. A feature of FIG. 8 is that the RAM layer 802 is composed of a magneto-optical film. The magneto-optical film can reproduce or record / erase information by setting the direction of its magnetic pole upward or downward. The features of the other constituent elements are the same as those in FIG.

Reference numeral 806 denotes a light beam, which is emitted from the substrate 801 side. When recording, reproducing, or erasing a signal in the RAM layer 802, the light beam 806 emits light to the RAM layer 8.
Controlled to focus on 02. Further, when the signal is reproduced by the ROM layer 803, the light beam 806 is controlled so as to focus on the ROM layer 803. When the RAM layer 802 including a magneto-optical film is used, there is almost no change in the transmittance or the reflectance of the RAM layer 802 between the case where the information is recorded and the case where the information is not recorded. The information reproduction signal of the layer 803 is hardly affected.

As described above, by forming the recording / reproducing / erasable layer by the magneto-optical film, it is possible to record a signal on the recording / reproducing / erasable layer in advance, which is required in the case of the phase change film. It is possible to stably read a signal from a layer that can only reproduce the signal.

In the case of FIGS. 1 to 8 described above, the multi-layer disc described in each of the figures is replaced by two.
Although one optical disk is formed by laminating one optical disk, one optical disk of such a structure is used as an optical disk for one side, and the other optical disk having another structure is used for adhering them. It is also conceivable to form one optical disk by For example, a single-layer or multi-layer ROM disk having at least one layer (ROM layer) capable of only reading out signals as shown in FIG. It may be one optical disc. A single-layer or multi-layer RAM disk having at least one layer (RAM layer) capable of recording / reproducing signals as shown in FIG.
It is also conceivable that the optical disc and the above-mentioned multilayer disc are bonded together to form one optical disc. Even in the case of the bonded optical disc as shown in FIGS. 9 and 10, FIG.
From the above, the same or similar action and effect as in the case of the optical disc by laminating shown in FIG. 8 are produced.

[0038]

Since the present invention is configured as described above, it has the following effects. A layer (RAM layer or ROM layer) capable of reading a signal by irradiating a light beam is arranged in at least two or more layers in a direction perpendicular to the light beam incident surface, and the layer capable of reading the signal (RAM Layer or ROM
By at least one recording / reproducing erasable layer (RAM layer) capable of recording and erasing a signal in addition to the layer reading the signal, and a layer (ROM layer) only capable of reading the signal. By laminating a multi-layered disc and an optical disc similar thereto to form one optical disc, it is possible to further increase the storage capacity of the optical disc, and to the RAM layer for recording signals. The time that can be recorded from the ROM layer of the optical disc is shortened, and dust is not mixed between the layers of the RAM layer and the ROM layer. To improve efficiency,
A large-capacity, high-speed and stable signal recording / reproducing / erasing becomes possible.

[Brief description of the drawings]

1 is a partial sectional view showing an embodiment of the present invention, particularly according to claim 1;

FIG. 2 is a diagram for explaining reproduction of an optical disc according to an embodiment of the present invention, particularly claim 1;

FIG. 3 is a partial sectional view showing an embodiment of the present invention, particularly according to Claims 10 and 11.

FIG. 4 is a partial sectional view showing an embodiment according to claim 2 of the present invention.

FIG. 5 is a diagram for explaining reproduction of an optical disc according to an embodiment of the present invention, particularly claim 2;

FIG. 6 is a partial sectional view showing an embodiment according to claim 3 of the present invention.

FIG. 7 is a diagram for explaining signal reproduction in the embodiment according to claim 4 of the present invention.

FIG. 8 is a partial sectional view showing an embodiment according to claim 6 of the present invention.

FIG. 9 is a partial sectional view showing an embodiment according to claim 13 of the present invention.

FIG. 10 is a partial sectional view showing an embodiment according to claim 14 of the present invention;

FIG. 11 is a schematic diagram showing a first conventional example.

FIG. 12 is a partial partial sectional view showing a first conventional example.

FIG. 13 is a partial partial sectional view showing a second conventional example.

FIG. 14 is a partial partial cross-sectional view showing a third conventional example.

[Explanation of symbols]

101, 401, 901, 1201, 1403 Substrate 102, 303, 403, 903, 1003 RO
M layer 103, 302, 402, 902, 1002 RA
M layer 104, 304, 404, 904, 1402 Intermediate layer 105, 405, 607, 905, 1204 Protective layer 106, 310, 406 Light beam 608 Reflective layer 1101 Partial ROM disk 1102, 1202 RA
M part 1103, 1203 RO
M part 1301 RO
M disk 1302 RA
M disk 1303 hollow part 1304, 1401 recording film

Claims (15)

[Claims] 1. A multi-layered optical disk comprising at least two layers capable of reading a signal by irradiating a light beam, the layers being arranged in a direction perpendicular to a light beam incident surface.
In an optical disc made by sticking together,
The signal readable layer is at least one recording / reproducing / erasable layer capable of recording / erasing a signal in addition to reading the signal, and a layer only capable of reading the signal. An optical disc comprising two multi-layer discs consisting of a. 2. In the multi-layer disc, among the layers capable of reading out signals, which are arranged in at least two or more in a direction perpendicular to the light beam incident surface, the recording / reproducing erasable layer is a light beam incident surface. The optical disc according to claim 1, wherein the optical disc is provided at a position closest to the optical disc. 3. The optical disc according to claim 2, wherein the recording / reproducing / erasable layer is composed of a phase change film. 4. A multi-layered optical disc comprising at least two layers capable of reading out signals by irradiating a light beam in a direction perpendicular to the light beam incident surface.
In an optical disc made by sticking together,
The signal readable layer is at least one recording / reproducing / erasable layer capable of recording / erasing a signal in addition to reading the signal, and a layer only capable of reading the signal. The recording / reproducing erasable layer is a layer formed of a phase-change film and provided at a position closest to the light beam incident surface of at least two layers arranged in a direction perpendicular to the light beam incident surface. And, when the multi-layer optical disk is first used by a person who uses the multi-layer optical disk for the first time, a meaningless signal is already recorded over the entire surface of the recordable / reproducible erasable layer. An optical disc comprising two laminated multi-layer discs bonded together. 5. A signal having a meaningful information property instead of the meaningless signal is recorded over the entire surface of the recordable / reproducible layer. optical disk. 6. The optical disk according to claim 2, wherein the recording / reproducing / erasable layer is composed of a magneto-optical film. 7. A transparent substrate capable of transmitting light, a first layer formed on one surface of the transparent substrate and capable of reading a signal, and a first layer capable of reading the signal. An intermediate layer made of a UV-curable resin which is formed on one surface and opposite to the surface on which the transparent substrate is formed and which can transmit light, and the signal on one surface of the intermediate layer. A second layer capable of reading a signal formed on a surface opposite to the surface having a first layer capable of reading a signal, and a second layer capable of reading the signal And a protective layer formed on one surface of the protective layer formed on the surface opposite to the surface on which the intermediate layer is formed.
The optical disc according to claim 1, wherein the optical disc is formed by laminating a plurality of sheets. 8. The information signal is expressed on the one surface of the transparent substrate where the first layer from which the signal can be read is formed and the surface on which the first layer from which the signal can be read is formed. Second layer which is formed of a metal reflective layer capable of reflecting the light formed on the information pit with the information pit formed by molding in advance as a shape to be read, and capable of reading the signal Is constituted by the layer capable of being recorded / reproduced / erased.
The described optical disc. 9. The first layer from which the signal can be read is constituted by the recording / reproducing / erasable layer, and the second layer from which the signal can be read is the intermediate layer. Formed on the information pit with an information pit previously formed by molding as a shape expressing the information signal on the surface on one side where the second layer from which the signal can be read is formed The optical disc according to claim 7, wherein the optical disc is formed of a metal reflective layer capable of reflecting the emitted light. 10. An optical disc in which two layers of optical discs each having a layer from which a signal can be read out by irradiating a light beam are arranged at least three in a direction perpendicular to a light beam incident surface. , A light-transmissive transparent substrate disposed as one outermost layer, a protective layer disposed as another outermost layer, and at least three or more disposed between the transparent substrate and the protective layer And a plurality of intermediate layers made of a material capable of transmitting light while isolating each of the signal readable layers. The signal readable layer is capable of recording and erasing the signal in addition to reading the signal, and at least one recording / reproducing erasable layer and the signal reading / erasing layer. 2. The optical disc according to claim 1, wherein two multi-layer discs each having a structure consisting of a layer that can only be ejected are laminated together. 11. The optical disc according to claim 10, wherein the intermediate layer is made of a photopolymer. 12. An optical disc formed by laminating two optical discs, wherein a layer capable of reading out a signal by irradiating at least two light beams arranged in a direction perpendicular to a light beam incident surface, At least one recording / reproducing erasable layer capable of recording and erasing the signal in addition to reading the signal;
At least one or more first optical disc composed of a layer capable of reading signals and a layer capable of reading signals by irradiating a light beam are arranged in a direction perpendicular to the light beam incident surface. An optical disc, characterized in that the optical disc and the second optical disc are bonded together. 13. The optical disc according to claim 12, wherein the signal readable layer in the second optical disc is a signal readable layer only. 14. The layer capable of reading the signal on the second optical disc is a layer capable of recording / reproducing and erasing the signal in addition to reading the signal. The optical disc according to claim 12, wherein the optical disc is an optical disc. 15. The thickness of the intermediate layer is about 40 μm, and the total thickness of the optical disc is about 1.2 mm.
The optical disc according to claim 7 or 10, wherein the optical disc is configured to: