JPH11250497A - Information recording medium and its recording/ reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composite optical disk and its recording/reproducing device capable of sharply improving capacity while holding extendability including reaction to different wavelength and allowed to be easily operated by a user. SOLUTION: In an optical disk 1 constituted of arranging a magneto-optical recording layer 1c capable of reacting to light of 650 nm wavelength on the surface of the substrate 1a, on which light is made incident without being transmitted through a substrate 1a and arranging a reproducing-only recording medium layer 1d capable of reacting to light of 790 nm wavelength on the irradiation surface of transmitted light through the substrate 1a stuck close to the layer 1c, a magnetic circuit 2c impresses an external magnetic field while converging light of 650 nm wavelength exiting from a light source 2 by an objective lens 2b and irradiating the layer 1c with the coverged light to record/reproduce information in/from the disk 1. On the other hand, light of 790 nm wavelength exiting from a light source 3 is converged by an objective lens 3b and the layer 1d is irradiated with the converged light to execute reproduction. Consequently the composite information recording medium and its recording/reproducing device sharply improving the capacity of the optical disk 1, provided with extendability including also medium structure reacting to different wavelength and allowed to be easily operated by a user are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording medium for optically recording and reproducing information, and a recording and reproducing apparatus for the information recording medium.

[0002]

2. Description of the Related Art The modern age is said to be the information age, and technical development of a high-density, large-capacity memory, which is the core of the age, is being actively carried out. The capability required for the memory includes high density, large capacity, high reliability, as well as a rewriting function.Optical disc memory is most attracted to satisfy these requirements. And a recording / reproducing apparatus for the information recording medium.

Conventionally, as an optical disk memory, an information recording medium which is an optical disk and a recording / reproducing apparatus which is a drive thereof have been commercialized typified by a CD or a DVD, and a number of reports have been made on technologies relating thereto.

[0004] Hereinafter, the most common CD or CDROM as a conventional example and its drive will be described with reference to the drawings.

FIG. 8 is a diagram for explaining a schematic configuration of an information recording medium, ie, an optical disk, CD or CDROM, and an optical head unit for detecting a signal in a recording / reproducing apparatus, ie, a drive. Will be described.

In FIG. 8, reference numeral 91 denotes a CD or CDR.
The optical disc 91a is an OM, and the thickness of the optical disc 91a is 1.
2 mm substrate, 91b is the light incident surface of substrate 91a, 91c
Is a medium layer having pits formed on a surface irradiated with light transmitted through the substrate 91a, and 91d is a protective layer for protecting the medium layer 91c. Reference numeral 92 denotes an optical head for detecting a signal in the drive of the optical disk 91; 92a, a light emitting / receiving element for irradiating the optical disk 91 with light having a wavelength of about 790 nm and detecting reflected light from the optical disk 91; A lens that collects light and forms an image on the medium layer 91c of the optical disc 91. Here, components that are not based on the gist of the present invention, such as motors, circuits, mechanisms, and the like, which are other components of the drive, are not shown or described.

The operation of the conventional example shown in FIG. 8 will be described below. Light receiving / emitting element 92 of optical head 92
A light having a wavelength of about 790 nm from the lens a
The light enters the light incident surface 91b of the optical disk 91 via the optical disk 91, passes through the substrate 91a having a thickness of about 1.2 mm, and forms an image on the medium layer 91c. The imaged light is reflected by the medium layer 91c, follows the reverse path, and reenters the light emitting / receiving element 92a of the optical head 92. Here, a servo signal and an information signal from the optical disk 91 are detected. Since the optical disk 91 is a CD or CDROM, the medium layer 91c has a reflectance of 70%.
The front and rear pits are formed, and the information signal is detected as the presence or absence of the pit due to the intensity of the reflected light.

As a next conventional example, a description will be given of a read-only DVD and its drive, which have been commercialized since 1996 and have attracted much attention, with reference to the drawings.

FIG. 9 is a diagram for explaining a schematic configuration of a read-only type DVD which is an information recording medium, ie, an optical disk, and an optical head unit for detecting a signal in the recording / reproducing apparatus, ie, a drive. The operation will be described.

In FIG. 9, 93 is an optical disk which is a read-only DVD, 93a is a substrate having a thickness of about 0.6 mm which transmits light, 93b is a light incident surface of the substrate 93a,
Reference numeral 3c denotes a first medium layer having pits formed on a surface irradiated with light transmitted through the substrate 93a, and reference numeral 93d denotes a pit formed on a surface irradiated with light transmitted through the substrate 93a and the first medium layer 93c. The second medium layer 93e is the first medium layer 93
c, a protective layer for protecting the second medium layer 93e, 93f is a substrate having the same properties as the substrate 93a.

Reference numeral 94 denotes an optical head for detecting signals in a drive of the optical disk 93, and 94a denotes an optical disk 9
3, a light emitting / receiving element for irradiating light with a wavelength of about 650 nm and detecting reflected light from the optical disc 93; a light collecting element 94b collects light from the light receiving / emitting element 94a; The lens forms an image on the second medium layer 93d. Here, components that are not based on the gist of the present invention, such as motors, circuits, mechanisms, and the like, which are other components of the drive, are not shown or described.

The operation of the conventional example shown in FIG. 9 will be described below. Light receiving / emitting element 94 of optical head 94
A light having a wavelength of about 650 nm from the lens a
Passes through the substrate 93a and enters the first medium layer 93c and the second medium layer 9 through the substrate 93a.
An image is formed on 3d. The imaged light is reflected by the first medium layer 91c and the second medium layer 93d, and reenters the light receiving / emitting element 94a of the optical head 94 along the reverse path. Here, a servo signal and an information signal from the optical disk 93 are detected.
The medium layer 93c and the second medium layer 93d are formed with pits having a predetermined reflectance and transmittance, respectively, and the information signal is detected as the presence or absence of a pit due to the intensity of the reflected light.

In the conventional example shown in FIG. 9, a single-sided read-out dual-layer optical disk structure of a read-only DVD is shown. That is, the structure is such that the substrate 93a has two medium layers and the substrate 93f has no medium layer. In a read-only DVD, in addition to this structure, a single-sided readout single-layer optical disc structure in which the substrate 93a has a single medium layer and the substrate 93f does not have a medium layer, the substrate 93a has a single medium layer and the substrate 93f also has a medium layer Double-sided readout two-layer optical disk structure with one medium layer structure, double-sided readout three-layer optical disk structure with two medium layers on substrate 93a and one medium layer on substrate 93f, substrate with two layers on medium substrate 93a 93
For f, a double-sided readout four-layer optical disk structure having a structure of two medium layers has been proposed.

[0014]

However, the above-mentioned conventional configuration has the following problems.

The optical disk 91 shown in FIG. 8 is a CD or a CD.
In the ROM, since the medium layer 91c is basically a single layer,
The capacity of the optical disc 91 is uniquely determined to be about 650 MB. Regardless of the type of CD or CDROM, the only way to increase the capacity of such a single-layer optical disk is to increase the recording density on the optical disk 91, such as shortening the wavelength, narrowing the track, and shortening the pits. There is no means, and there is a problem that the capacity of the optical disc 91 is limited by the light condensing ability of the lens 92.

The optical disk 93 shown in FIG. 9 is a read-only type DVD.
And the first medium layer 93
c and a second medium layer 93d. Therefore, shortening of the wavelength, narrowing of the track, and shortening of the pit are achieved, and the first medium layer 93 is formed.
A capacity of about 4.7 GB is realized with only c, and a large capacity of about 9.4 GB is realized by providing the second medium layer 93d. However, as an optical disk for the future, it is not a medium structure that responds to different wavelengths,
There is a problem in that the light condensing ability is limited by the presence of the substrate 93a through which the light beam condensed by the lens 94b passes, and the capacity of the optical disc 93 is not dramatically improved. In addition, there is also a problem that it cannot be said that the optical disk is a composite type optical disk which is easy to use from the viewpoint of the user because the medium is not simply combined with a medium having a different property.

The present invention provides a composite type optical disk and a recording / reproducing apparatus which are easy to use from the viewpoint of a user and have a dramatic improvement in capacity after providing expandability including reaction to different wavelengths. The purpose is to do.

[0018]

In order to solve this problem, an information recording medium according to the present invention comprises a substrate which transmits light, and a first medium which is disposed on the surface of the substrate where light enters without passing through the substrate. A structure including a first medium layer and a second medium layer disposed on a surface irradiated with light transmitted through the substrate, or a substrate transmitting light, and a light transmitting through the substrate. A first medium layer disposed on the surface of the substrate on which light is incident, and a second medium layer disposed in close contact with the first medium layer and disposed on a surface irradiated with light transmitted through the substrate. Configuration.

The first medium layer and the second medium layer can be applied to either a medium material that responds to light having substantially the same wavelength or a medium material that responds to light having a different wavelength.

Further, it has a substrate that transmits light, and a first medium layer and a second medium layer that are arranged in close contact with each other in the order in which the light transmitted through the substrate is irradiated. The second medium layer and the second medium layer have different wavelengths to be reacted.

Further, in the above information recording medium, the first
The second medium layer and the second medium layer may have the same properties or may have different properties. Further, the substrate may be a single plate or a structure in which two substrates are bonded.

As a result, the optical disk for the future has expandability including a medium structure that responds to different wavelengths, and in the case of a configuration in which the light beam by the light condensing means reacts the medium layer without transmitting through the substrate. It is possible to dramatically improve the capacity of an information recording medium without limiting its light condensing ability by so-called surface recording / reproducing, and when combining media of different properties, a composite type that is easy for the user to use is used. An information recording medium and its recording / reproducing device can be obtained.

[0023]

DETAILED DESCRIPTION OF THE INVENTION An information recording medium according to claim 1 of the present invention comprises a substrate that transmits light, and a first medium layer disposed on the surface of the substrate where light enters without passing through the substrate. When,
Since it has the first medium layer and the second medium layer disposed on the surface irradiated with light transmitted through the substrate, the first medium layer
The medium layer has a function of enabling so-called surface recording / reproduction and capable of dramatically improving the capacity.

According to a second aspect of the present invention, there is provided an information recording medium, comprising: a substrate that transmits light; a first medium layer disposed on a surface of the substrate on which light enters without passing through the substrate; Since the first medium layer has a second medium layer disposed in close contact with the first medium layer and disposed on a surface irradiated with light transmitted through the substrate, the first medium layer can perform so-called surface recording / reproduction. Since the recording / reproducing of the two medium layers is not affected by the first medium layer, it has an effect of stably increasing the capacity dramatically.

According to a third or fourth aspect of the present invention, in the information recording medium according to the first or second aspect, the first medium layer and the second medium layer react to light having substantially the same wavelength. Since the recording medium is formed of a medium material or a medium material that responds to light of different wavelengths, the degree of freedom of the information recording medium can be improved. Further, claims 13, 14, 16, and 17 are the recording / reproducing apparatuses for the information recording medium according to claims 1 to 4.

The information recording medium according to claim 5, wherein the first medium layer and the second medium are disposed in close contact with each other in the order in which light transmitted through the substrate is irradiated with the light transmitted through the substrate. Since the first medium layer and the second medium layer have different wavelengths that react with each other, the first medium layer and the second medium layer have an effect that the expandability as viewed from the user can be enhanced. According to a fifteenth aspect of the present invention, there is provided a recording / reproducing apparatus for an information recording medium according to the fifth aspect.

According to the information recording medium of the present invention, the distance between the first medium layer and the second medium layer in the information recording medium of the second to fifth aspects is 100 μm or less. The surface recording / reproducing function or the recording / reproducing function with a single irradiation system has an effect that makes it more practical.

According to a seventh aspect of the present invention, in the information recording medium according to the first to sixth aspects, both the first medium layer and the second medium layer are of a read-only reflective type. Media, a write-once type medium, a magneto-optical recording medium, a phase change recording medium, and the like, or a structure of a medium layer having the same property, or a first medium layer and a second medium layer having different properties, The first medium layer and the second medium layer have a configuration of a medium layer having any one property of a read-only reflection type medium, a write-once type medium, a magneto-optical recording medium, and a phase change recording medium. It has expandability including a responsive medium structure, dramatically increases the capacity of the information recording medium, and provides a user-friendly composite information recording medium and its recording / reproducing device. Having.

According to a ninth aspect of the present invention, in the information recording medium according to the first to eighth aspects, the first medium layer and the second medium layer are each a so-called CD having a wavelength of about 790 nm. Wavelength of light or 600nm wavelength
Since the apparatus is provided with a structure that responds to either one of the so-called red wavelength lights, it has an effect that the recording / reproducing function by the wavelength used and its irradiation system becomes more practical.

[0030] The information recording medium according to the tenth to twelfth aspects of the present invention is the information recording medium according to the first to ninth aspects, wherein the first medium layer and the second medium layer are formed. A single plate having a substrate thickness of 1.2 mm or less; a plate member having a substrate thickness of 0.6 mm or less in a region where the first medium layer and the second medium layer are formed; Are bonded together with the surface opposite to the surface on which light is irradiated to the first medium layer as a bonding surface, or in the region where the first medium layer and the second medium layer are formed. Since the thickness of the substrate is a plate member having a thickness of 0.6 mm or less, and the first medium layer is bonded to a plate member having no medium layer on the surface opposite to the surface irradiated with light, the future Scalability, including a medium structure that responds to different wavelengths The information recording medium of good composite convenient when viewed from the user, or a more practical functions of recording and reproducing by the irradiation system, a bonded structure has an effect that it becomes possible to improve further the capacity.

[0031]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) The structure and operation of a first embodiment of the present invention will be described below with reference to FIG.

In FIG. 1, reference numeral 1 denotes an optical disk; 1a, a substrate having a thickness of about 1.2 mm that transmits light; 1b, a first protective layer provided on the light incident surface of the substrate 1a;
b, a first medium layer having a constant transmittance and reacting to light having a wavelength of about 650 nm;
d is a second medium layer in which pits are formed on a surface irradiated with light transmitted through the substrate 1a, and is a read-only reflective medium that responds to light having a wavelength of about 790 nm, and 1e is a second medium layer 1d.
This is a second protective layer for protecting the (read-only reflective medium).

Reference numeral 2 denotes a first optical head for detecting a signal of a first medium layer 1c (magneto-optical recording medium) in a drive of the optical disk 1, and 2a denotes a disk having a wavelength of 650n on the optical disk 1.
The light receiving / emitting element 2b which irradiates light of about m and detects the reflected light from the optical disk 1 collects the light from the light receiving / emitting element 2a and forms an image on the first medium layer 1c (magneto-optical recording medium). The lens 2c is a magnetic circuit for applying an external magnetic field to the first medium layer 1c (magneto-optical recording medium).

Reference numeral 3 denotes a drive of the optical disk 1, a second optical head for detecting a signal of the second medium layer 1 d (read-only reflection type medium), and 3 a, the optical disk 1 having a wavelength of 79
The light emitting / receiving element 3b which irradiates light of about 0 nm and detects the reflected light from the optical disk 1, condenses the light from the light emitting / receiving element 3a, and couples the light to the second medium layer 1d (read-only reflective medium). It is a lens for imaging.

However, here, components not based on the gist of the present invention, such as a motor, a circuit, and a mechanism, which are other components of the drive, are neither shown nor described.

The operation of FIG. 1 will be described. 650 nm wavelength from the light receiving / emitting element 2a of the first optical head 2
The emitted light before and after is incident on the first protective layer 1b, which is the light incident surface of the optical disk 1, via the lens 2b, and forms an image on the first medium layer 1c (magneto-optical recording medium) which is in close contact with the first protective layer 1b. This gives an external magnetic field. In the present embodiment, as an example of performing so-called magnetic field modulation recording, during recording, the light receiving / emitting element 2a emits light power of a constant intensity to perform recording by a modulation signal of the magnetic circuit 2c, and during reproduction, the magnetic circuit 2c does not operate. The light emitting / receiving element 2b is the first medium layer 1c.
The reproducing operation is performed by detecting the rotation of the polarization plane from the (magneto-optical recording medium).

On the other hand, the light receiving / emitting element 3a of the second optical head 3
A light having a wavelength of about 790 nm from the optical disc 1 passes through a lens 3b, a first protective layer 1b which is a light incident surface of the optical disc 1, and a first medium layer 1c (a magneto-optical recording medium) having a fixed transmittance in close contact with the first protective layer 1b. ) And then through the substrate 1a and the second
An image is formed on the medium layer 1d (a read-only reflective medium). The imaged light is reflected by the second medium layer 1d (reflection-only medium for reproduction), and follows a reverse path to the light receiving / emitting element 3a of the optical head 3.
Again. Here, a servo signal and an information signal from the second medium layer 1d (read-only reflective medium) are detected, and the second medium layer 1d (read-only reflective medium) has a reflectance of 70%.
% Pits are formed, and the information signal is detected as the presence or absence of a pit due to the intensity of the reflected light.

Although the first optical head 2 and the second optical head 3 are configured independently in FIG. 1, any other optical head may be used as long as the function can be achieved by a single optical head by devising a light emitting / receiving element and a lens. Further, in the present embodiment, the first medium layer 1c and the second medium layer 1d are medium layers that react to light of different wavelengths, but these two layers are medium layers that react to light of substantially the same wavelength. It goes without saying that this may be the case.

As described above, in the present embodiment, when recording / reproducing the first medium layer 1c (magneto-optical recording medium) with the first optical head 2, so-called surface recording / reproducing is possible, and the influence of the substrate 1a is reduced. Since no light is received, the light collecting ability of the lens 2b is not limited, so that the capacity can be dramatically improved. Further, the second optical head 3 controls the second medium layer 1
d (read-only reflective medium), the transmission of the first protective layer and the first medium layer of the optical disc 1 may be changed, for example, by using an existing CD player or CD.
Reproduction with a ROM drive is also possible. That is, the present invention provides a composite optical disc 1 and a recording / reproducing apparatus for the same, which are easy to use for a user because media having different properties responding to different wavelengths are combined.

(Embodiment 2) The configuration and operation of a second embodiment of the present invention will be described below with reference to FIG.

In FIG. 2, 1 is an optical disk, 1a is a substrate having a thickness of about 1.2 mm that transmits light, 1b is a first protective layer provided on a surface on which light enters without passing through the substrate 1a, 1c.
Is a first medium layer in close contact with the first protective layer 1b and has a wavelength of 650n.
The magneto-optical recording medium 1d that responds to light of about m is a second medium layer in which pits are formed on a surface irradiated with light transmitted through the light incident surface 1f and the substrate 1a, and responds to light of about 790 nm in wavelength. Read-only reflective medium, 1e is second medium layer 1d
A second protective layer for protecting the (read-only reflective medium);
The second medium layer 1d (the read-only reflective medium) is the second protective layer 1
e, it is in close contact with the first medium layer 1c (magneto-optical recording medium).

The optical disc 1 of this embodiment has exactly the same arrangement of the symbols attached to the components of the first embodiment of FIG. 1, but has a second medium layer 1d (a read-only reflective medium). Are different from those in FIG.

Reference numeral 2 denotes a first optical head for detecting a signal of the first medium layer 1c (magneto-optical recording medium) in the drive of the optical disk 1, and 2a denotes a disk having a wavelength of 650n
The light receiving / emitting element 2b which irradiates light of about m and detects the reflected light from the optical disk 1 collects the light from the light receiving / emitting element 2a and forms an image on the first medium layer 1c (magneto-optical recording medium). The lens 2c is a magnetic circuit for applying an external magnetic field to the first medium layer 1c (magneto-optical recording medium).

Reference numeral 3 denotes a second drive in the drive of the optical disc 1.
The second optical head 3a for detecting a signal of the medium layer 1d (read-only reflection type medium) has a wavelength of 790 on the optical disc 1.
The light emitting / receiving element 3b which irradiates light of about nm and detects the reflected light from the optical disk 1, condenses the light from the light receiving / emitting element 3a, and couples the light to the second medium layer 1d (a read-only reflective medium). It is a lens for imaging.

However, here, components not based on the gist of the present invention, such as a motor, a circuit, and a mechanism, which are other components of the drive, are neither shown nor described.

The operation of FIG. 2 will be described.
As described above, differences from FIG. 1 will be mainly described.

The outgoing light having a wavelength of about 650 nm from the light emitting / receiving element 2a of the first optical head 2 enters the first protective layer 1b, which is the light incident surface of the optical disc 1, via the lens 2b, and the first protective layer 1b is in close contact with the first protective layer 1b. An external magnetic field is applied by the magnetic circuit 2c at the same time when an image is formed on the medium layer 1c (magneto-optical recording medium). The recording / reproducing operation of this embodiment is the same as that of the first embodiment shown in FIG.

On the other hand, the light emitting / receiving element 3a of the second optical head 3
The emitted light having a wavelength of about 790 nm from the optical disk 1 passes through the lens 3b, passes through the light incident surface 1f of the optical disc 1 and the substrate 1a, and forms an image on the second medium layer 1d (read-only reflective medium). The imaged light is reflected by the second medium layer 1d (reflection-only medium for reproduction), and follows the reverse path to the light emitting / receiving element 3 of the optical head 3.
a again. The reproducing operation here is the same as in the first embodiment of FIG.

As described above, in the present embodiment, when recording / reproducing the first medium layer 1c (magneto-optical recording medium) with the first optical head 2, so-called surface recording / reproducing is possible, and the influence of the substrate 1a is reduced. Since no light is received, the light collecting ability of the lens 2b is not limited, and the capacity can be dramatically improved.

Further, the second optical head 3 controls the second medium layer 1
When reproducing d (reproduction-only reflective medium),
As shown in FIG. 1, the light does not pass through the first protective layer 1b and the first medium layer 1c (magneto-optical recording medium) of the optical disk 1 via the lens 3b, and the light incident surface 1f is different from the first protective layer 1b by the substrate 1
Since the light is present on the opposite side of a, the incident light passing through the lens 3b simply passes through the substrate 1a and forms an image on the second medium layer 1d (read-only reflective medium). That is, in addition to the first embodiment shown in FIG. 1, the reproduction of the second medium layer is not affected by the first medium layer at all, so that stable reproduction is possible. Therefore, it is possible to realize an optical disk 1 and a recording / reproducing apparatus which are easy to use from the viewpoint of a user, for example, such that reproduction can be performed with an existing CD player or CD ROM drive.

In this embodiment, the first medium layer 1c and the second medium
Although the medium layer responds to light having a wavelength different from that of the medium layer 1d, it goes without saying that these two layers may be medium layers responding to light having substantially the same wavelength.

In FIG. 2, the first optical head 2 and the second optical head 3 are located on opposite sides of the optical disk 1, but in this case, for example, the first medium layer 1c ( This has a special effect that the recording and reproduction of the magneto-optical recording medium and the reproduction of the second medium layer 1d (reproduction-only reflective medium) by the second optical head 3 can be performed simultaneously.

Conversely, for example, as shown in FIG. 3, a drive in which the first optical head 2 and the second optical head 3 exist on the same side of the optical disk 1 as shown in FIG. In this case, in order to achieve the function, the optical disk 1 may be inverted and mounted on the drive as shown in FIGS. In other words, simultaneous operation of the two medium layers is impossible, but recording and reproduction of each medium layer can be performed independently, and the entire drive can be made thinner. In addition, any function can be achieved with one optical head by devising a light receiving / emitting element and a lens.

(Embodiment 3) The configuration and operation of a third embodiment of the present invention will be described below with reference to FIG.

In FIG. 4, reference numeral 1 denotes an optical disk; 1a, a substrate having a thickness of about 1.2 mm that transmits light; 1f, a light incident surface of the substrate 1a;
A wavelength of 65% is applied to the first medium layer irradiated by light transmitted through the first medium layer.
A magneto-optical recording medium that responds to light of about 0 nm,
The protective layer 1d is a second medium layer closely contacted with the first medium layer 1c within a distance of 100 μm. Light incident from the light incident surface 1f is irradiated by light transmitted through the substrate 1a, the first medium layer 1c, and the first protective layer. The second medium layer having pits formed on the surface
A read-only reflective medium that responds to light of about 0 nm, 1e is a first medium layer (magneto-optical recording medium) 1c and a second medium layer 1d.
This is a second protective layer for protecting the (read-only reflective medium).

In this embodiment, the arrangement of the symbols attached to the components of the first embodiment shown in FIG.
The position where the medium layer 1c (magneto-optical recording medium) is formed is shown in FIG.
Is different from

Reference numeral 2 denotes a first optical head for detecting a signal of the first medium layer 1c (magneto-optical recording medium) in a drive of the optical disk 1, and 2a denotes a disk having a wavelength of 650 nm.
The light receiving / emitting element 2b which irradiates light of about m and detects the reflected light from the optical disk 1 collects the light from the light receiving / emitting element 2a and forms an image on the first medium layer 1c (magneto-optical recording medium). The lens 2c is a magnetic circuit for applying an external magnetic field to the first medium layer 1c (magneto-optical recording medium).

Reference numeral 3 denotes a drive of the optical disk 1, a second optical head for detecting a signal of the second medium layer 1 d (read-only reflection type medium), and 3 a, the optical disk 1 having a wavelength of 79
The light receiving / emitting element 3b which irradiates light of about 0 nm and detects the reflected light from the optical disc 1, condenses the light from the light receiving / emitting element 3a, and condenses it to the second medium layer 1d (read-only reflective medium). It is a lens for imaging.

However, here, components not based on the gist of the present invention, such as a motor, a circuit, and a mechanism, which are other components of the drive, are neither shown nor described.

The operation of FIG. 4 will be described.
As described above, differences from FIG. 1 will be mainly described.

Outgoing light having a wavelength of about 650 nm from the light emitting / receiving element 2a of the first optical head 2 passes through the lens 2b, the light incident surface 1f of the optical disk 1, the substrate 1a, and the first medium layer 1c (the magneto-optical recording medium). ) And the magnetic circuit 2
An external magnetic field is applied by c. The recording / reproducing operation of this embodiment is the same as that of the first embodiment shown in FIG.

On the other hand, the light emitting / receiving element 3a of the second optical head 3
The light emitted from the optical disc having a wavelength of about 790 nm passes through the lens 3b, the light incident surface 1f of the optical disc 1, the substrate 1a, the first medium layer 1c (magneto-optical recording medium), and the second medium layer 1d (read-only reflective type). Medium). The imaged light is reflected by the second medium layer 1d (reflection-only medium for reproduction), and follows the reverse path to enter the light receiving / emitting element 3a of the optical head 3 again. The reproducing operation here is the same as in the first embodiment of FIG.

As described above, in the present embodiment, as in the first and second embodiments, the first optical head 2 uses the first medium layer 1c.
So-called surface recording / reproducing is not possible even when performing recording / reproducing on (magneto-optical recording medium). However, since it has two medium layers, the capacity can be improved as compared with a single-layer optical disc.

Further, unlike the conventional example of the DVD shown in FIG. 9, since the first medium layer 1c and the second medium layer 1d have different wavelengths to react with each other, the usability with enhanced expandability from the viewpoint of the user. And a recording / reproducing apparatus of the composite type optical disc 1 with good quality.

That is, in the configuration shown in FIG. 4, if the second medium layer 1d is, for example, a CD format, the second medium layer 1d can be reproduced by an existing CD player, CDROM drive, DVD player, or DVDROM drive.

When the first medium layer 1c is not a magneto-optical recording medium but a read-only reflective medium of, for example, a read-only DVD format, both the first medium layer 1c and the second medium layer 1d are DVD players or DVD ROMs. Drive playback is also possible.

Further, as an effect of the present embodiment, the distance between the first medium layer 1c and the second medium layer 1d is 100 μm or less.
As is realized by a VD player or a DVD ROM drive, there is a unique effect that it is easy to actually introduce a technology capable of achieving a function with one optical head by devising a light receiving / emitting element and a lens.

The first medium layer and the second medium layer of the information recording medium of the present invention correspond to the magneto-optical recording responsive to the light having a wavelength of about 650 nm in the embodiment described with reference to FIGS. The medium (first medium layer 1c) and the read-only reflective medium (second medium layer 1d) in which the second medium layer 1d reacts to light having a wavelength of about 790 nm are not limited. That is, the first medium layer 1c and the second medium layer 1d of the present invention
Means that when light for recording or reproduction irradiates the medium layer,
There is only a difference between not passing through the substrate or passing through,
It does not depend on the so-called properties of the media layer, such as the material applied, the optically detectable change process, the recording mode, the reproduction mode, etc. Therefore, the first medium layer 1c and the second medium layer are 1d, for example, media having the same properties such as a read-only reflective medium, a write-once medium, a magneto-optical recording medium, and a phase change recording medium. Layers,
Alternatively, unlike this combination, the first medium layer 1c is a medium layer having any one property of, for example, a read-only reflective medium, a write-once medium, a magneto-optical recording medium, and a phase change recording medium, and the second medium layer The layer 1d is a medium layer having a property different from that of the first medium layer 1c, and may be any one of a read-only reflective medium, a write-once medium, a magneto-optical recording medium, and a phase change recording medium.

With such a configuration, the information recording medium is provided with expandability, including a medium structure that responds to different wavelengths, dramatically increasing the capacity of the information recording medium, and being easy to use for the user. A composite information recording medium can be obtained, and a recording / reproducing apparatus using the composite information recording medium can be obtained.

Further, in the above embodiment, the first medium layer 1c and the second medium layer 1d respectively emit so-called CD wavelength light having a wavelength of about 790 nm or so-called red wavelength light having a wavelength of about 650 nm, that is, a wavelength of about 600 nm. A specific example is a medium layer that responds to any one of the lights, but the present invention is not limited to this combination. By taking the wavelength of the most common light source in the current market as an example,
The recording / reproducing function of the irradiation system is more practical.

Further, as the recording / reproducing devices of the first to third embodiments, the light emitting / receiving elements 2a and 3a and the lenses 2b and 3b are concrete examples, but the present invention is not limited to these.
For example, a floating head or SI
A recording / reproducing apparatus using a technology such as L is also possible.

(Embodiment 4) The configuration and operation of a fourth embodiment of the present invention will be described below with reference to FIG.

Embodiments 1 to 3 described with reference to FIGS.
The substrate 1a has a thickness of about 1.2 mm and is a so-called single-plate optical disk 1, but it is needless to say that the present invention is not limited to this thickness. An example of a so-called bonding structure will be described.

That is, the thickness of the region where the substrate is formed with the first medium layer 1c and the second medium layer 1d is, for example, about 0.6.
Each of the plate members has a thickness of about 1.2 mm and is bonded to the first medium layer 1c with a surface opposite to a surface on which light is irradiated to the first medium layer 1c.

In FIG. 5, FIGS. 5, 6, and 7 show the information recording media of the first embodiment of FIG. 1, the second embodiment of FIG. 2, and the third embodiment of FIG. FIG. 3 shows a diagram with a matching structure. Therefore, the components are all the same as those shown in FIGS. 1, 2 and 4 except for the bonding structure, and the operation and the effect exerted are completely the same. In FIGS. 5, 6 and 7, a plate member 1g is shown as a component instead of the component shown as the substrate 1a in FIGS. 1, 2 and 4 because of the bonding structure.

Further, in the present embodiment shown in FIGS. 5, 6 and 7, the substrates are the first medium layer 1c and the second medium layer 1d.
Is a plate member having a thickness of 0.6 mm or less in a region where is formed, and 1.2 mm or less in which a plate member having no medium layer is attached to a surface opposite to a surface on which light is irradiated to the first medium layer 1c. The thickness of the structure may be as follows. In this case, since the thickness of the substrate is reduced, the capacitance can be improved as compared with the embodiments of FIGS. 1, 2 and 4 described above.

5, 6 and 7, the capacity of the information recording medium whose capacity has been increased in FIGS. 1, 2 and 4 is further doubled, as demonstrated by the DVD technology. However, since the information recording medium may simply be inverted and mounted on the recording / reproducing apparatus, an extremely large effect can be realized as a technology for the future.

[0079]

As described above, according to the present invention, a substrate that transmits light, a first medium layer disposed on the surface of the substrate where light enters without passing through the substrate, and a first medium layer A second medium layer disposed on a surface irradiated with light transmitted through the substrate. Or a substrate that transmits light, and a first medium layer disposed on a surface of the substrate where light enters without passing through the substrate;
A second medium layer disposed in close contact with the first medium layer and disposed on a surface irradiated with light transmitted through the substrate. The first medium layer and the second medium layer may be formed of a medium that responds to light having substantially the same wavelength, or may be formed of a medium that responds to light having a different wavelength.

Further, it has a substrate that transmits light, and a first medium layer and a second medium layer that are arranged in close contact with each other in the order in which the light transmitted through the substrate is irradiated. The wavelengths at which the two medium layers react are different from each other.

Further, in the above information recording medium, the first
The second medium layer and the second medium layer may have the same properties or may have different properties. Further, the substrate may be a single plate or a structure in which two substrates are bonded.

As a result, the optical disk for the future has expandability including a medium structure that responds to different wavelengths, and in the case of a structure in which the light beam by the condensing means reacts the medium layer without transmitting through the substrate. It is possible to dramatically improve the capacity of an information recording medium without limiting its light condensing ability by so-called surface recording / reproducing, and when combining media of different properties, a composite type that is easy for the user to use is used. An information recording medium and its recording / reproducing device can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an information recording medium and a recording / reproducing apparatus thereof according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an information recording medium and its recording / reproducing apparatus according to a second embodiment of the present invention.

3A is a configuration diagram of an information recording medium according to a second embodiment of the present invention, and FIG. 3B is a configuration diagram of an optical system targeting one medium layer; FIG. Configuration diagram of the targeted optical system

FIG. 4 is a configuration diagram of an information recording medium and its recording / reproducing apparatus according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram of an information recording medium and a recording / reproducing apparatus according to an embodiment of Embodiment 5 of the present invention;

FIG. 6 is a configuration diagram of an information recording medium and a recording / reproducing apparatus according to another embodiment of the fifth embodiment of the present invention.

FIG. 7 is a configuration diagram of an information recording medium and its recording / reproducing apparatus according to another embodiment of the fifth embodiment of the present invention.

FIG. 8 is a configuration diagram of a conventional information recording medium and its recording / reproducing apparatus.

FIG. 9 is a configuration diagram of another conventional information recording medium and its recording / reproducing apparatus.

[Explanation of symbols]

 1, 91, 93 Optical disk 1a, 91a, 93a, 93f Substrate 1b, 1e, 91d, 93d Protective layer 1c, 1d, 91c, 93c, 93e Medium layer 1f, 91b, 93b Light incident surface 1g Plate member 2, 3, 92,94 Optical head 2a, 3a, 92a, 94a Light emitting / receiving element 2b, 3b, 92b, 94b Lens 2c Magnetic head

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI G11B 13/00 G11B 13/00 (72) Inventor ▲ Makoto Shimashima 1006 Kazuma Kazuma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Osamu Mizuno 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Inventor Hirotoshi Tomita 1006 Odaka Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (17)

[Claims] 1. A substrate transmitting light, a first medium layer disposed on a surface of the substrate on which light enters without passing through the substrate, and a light transmitted through the first medium layer and the substrate. An information recording medium comprising: a second medium layer disposed on a surface irradiated with light. 2. A substrate that transmits light, a first medium layer disposed on the surface of the substrate on which light enters without passing through the substrate, and the substrate disposed in close contact with the first medium layer. An information recording medium comprising: a second medium layer disposed on a surface irradiated with light transmitted through the second medium layer. 3. The information according to claim 1, wherein the first medium layer and the second medium layer are formed of a medium material responsive to light having substantially the same wavelength. recoding media. 4. The information recording medium according to claim 1, wherein the first medium layer and the second medium layer are formed of medium materials that react to light of different wavelengths. . 5. A first medium layer comprising: a substrate transmitting light; a first medium layer and a second medium layer disposed in close contact with each other in the order in which the light transmitted through the substrate is irradiated. An information recording medium, wherein the wavelength at which the second medium layer and the second medium layer react are different. 6. The distance between the first medium layer and the second medium layer is one.
The information recording medium according to any one of claims 2 to 5, wherein the thickness is not more than 00 µm. 7. A first medium layer and a second medium layer,
The information according to any one of claims 1 to 6, wherein the medium layer has the same property as any one of a read-only medium, a write-once medium, a magneto-optical recording medium, and a phase change recording medium. recoding media. 8. The first medium layer and the second medium layer have different properties, and the first medium layer is a read-only reflective medium,
Any one of a write-once medium, a magneto-optical recording medium, and a phase-change recording medium, wherein the second medium layer is any one of a read-only reflective medium, a write-once medium, a magneto-optical recording medium, and a phase-change recording medium The information recording medium according to any one of claims 1 to 6, wherein 9. The information recording medium according to claim 1, wherein a wavelength at which the first medium layer reacts with the second medium layer is approximately 790 nm or approximately 600 nm. . 10. A single plate having a thickness of at least 1.2 mm or less in a region where at least the first medium layer and the second medium layer are formed. An information recording medium according to claim 1. 11. A plate member having a thickness of 0.6 mm or less of a substrate in a region where at least a first medium layer and a second medium layer are formed, wherein each of the plate members is a first medium layer. The information recording medium according to any one of claims 1 to 9, wherein the two substrates are bonded together with a surface opposite to a surface on which light is applied to the substrate as a bonding surface. 12. A plate member having a thickness of 0.6 mm or less of a substrate in a region where at least the first medium layer and the second medium layer are formed, and a surface for irradiating the first medium layer with light. The information recording medium according to any one of claims 1 to 9, wherein a plate member having no medium layer is attached to a surface opposite to the surface. 13. Recording or reproduction of a first medium layer and a second medium layer on the information recording medium according to any one of claims 1, 3, 4, and 7 to 12. Playback device. 14. A recording / reproducing apparatus for recording / reproducing a first medium layer and a second medium layer with respect to the information recording medium according to claim 2 or 4. . 15. A recording / reproducing apparatus for recording / reproducing a first medium layer and a second medium layer with respect to the information recording medium according to claim 5. 16. A first irradiation system for condensing light on a first medium layer without passing through a substrate, and the first irradiation system exists on the opposite side in the substrate thickness direction, and a second irradiation system is provided. The recording / reproducing apparatus according to any one of claims 13 to 15, further comprising: a second irradiation system for transmitting and condensing light through the substrate to the medium layer. 17. A first irradiation system for condensing light on a first medium layer without passing through a substrate, and a first irradiation system on the same side as the first irradiation system in the thickness direction of the substrate. When mounted, the light is transmitted through the substrate to the second medium layer and condensed by being inverted in the thickness direction of the substrate, and is the same as or independent of the first irradiation system. The recording / reproducing apparatus according to any one of claims 13 to 15, further comprising a second irradiation system.