JP2003157573A - Flexible optical disk and optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk cartridge and an optical disk device which are thin and can increase the allowance with respect to the inclination of an optical disk even when a beam spot is reduced by shortening the wavelength of light and increasing the numerical aperture NA of the objective lens as a condensing means. SOLUTION: The disk substrate of the flexible optical disk 1 on which a recording medium layer 4 or a metallic reflecting layer 4' is to be formed is composed of a flexible metallic substrate 2 and a resin layer 3 formed on the substrate 2 and having a rugged pit pattern and/or a rugged guide groove pattern or a resin layer 3' having a rugged pit pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc for realizing high-density information recording or reproduction, and more specifically, an optical disc having flexibility and whether the optical disc is housed in an optical disc cartridge case. The present invention relates to an optical disc cartridge, and an optical disc device that records or reproduces information on or from these optical discs.

[0002]

2. Description of the Related Art In recent years, due to the development of optical discs capable of reproducing, recording and erasing information,
The spread of optical discs for consumer use and data storage has become remarkable. At present, research that satisfies further demands for higher density and larger capacity is being earnestly pursued.

In order to increase the density and the capacity of the optical disc, it is necessary to reproduce and record the information in a state where the mark (recording bit) that substantiates the recorded information on the optical disc is smaller. For this purpose, it is conceivable to reduce the spot diameter of the light beam applied to the optical disc.

In principle, the spot diameter of the light beam is λ /
Proportional to NA. (Λ: wavelength of light, NA: numerical aperture of objective lens)
By shortening the wavelength of light and increasing the numerical aperture NA of the objective lens, the diameter of the beam spot can be reduced and the density of the optical disc can be increased.

However, when the wavelength of light is shortened and the numerical aperture NA of the objective lens is increased, the tolerance for the tilt of the optical disk becomes narrow. This is because when the optical disc tilts, a large wavefront aberration occurs due to the tilt of the disc substrate (base portion of the optical disc) that transmits the light beam for recording and reproduction, and the light beam cannot be accurately focused. This is because it will end up. The wavefront aberration caused by the tilt of the disc substrate depends on the thickness of the disc substrate.

Therefore, in order to compensate for this, thinning of the disk substrate has been promoted. For example, in the case of a CD-ROM, the numerical aperture NA of the objective lens is 0.45 and the wavelength of light is 7
At 80 nm, the substrate thickness is 1.2 mm, while
The numerical aperture NA of the objective lens is 0.6, and the wavelength of light is 655n.
In a DVD-ROM having a thickness of 0.5 m, the substrate has a thickness of 0.
The thickness is set to 6 mm to increase the recording capacity and the allowable amount with respect to the inclination of the disk substrate.

However, when the disk substrate is further thinned, the rigidity of the disk substrate is lowered, and the tilt of the disk substrate is increased due to the surface wobbling of the disk substrate itself, which has the opposite effect.

On the other hand, in Japanese Patent Laid-Open No. 10-308059, the wavelength of light is shortened and the numerical aperture NA of the objective lens is reduced.
An optical disk device using a flexible disk substrate as shown in FIG. 27 has been proposed for the purpose of increasing the size.

This is a flexible optical disk 101.
Is a recording / reproducing device for performing recording / reproducing with respect to the optical disc 101, and a stabilizing plate 102 for stabilizing the rotation state of the optical disc 101 is provided, and the optical beam from the optical pickup 103 is focused and irradiated on the optical disc 101. The optical disc 101 fixed to the center hub 105 is rotationally driven by the spindle 106. At this time, the space between the optical disc 101 and the stabilizing plate 102 is in a reduced pressure state, and the optical disc 101 is attracted to the stabilizing plate 102. , Stabilizing plate 1
It rotates stably with a constant interval of 02. As a result, surface wobbling during rotation of the optical disc 101 is suppressed, and good recording / reproducing is performed.

According to this, it is possible to realize recording / reproducing in a recording / reproducing apparatus in which the wavelength of light is 650 nm or less and the numerical aperture NA of the objective lens group 104 is 0.7 or more.

Further, the above publication proposes that the stabilizing plate 102 is integrally formed with the disk cartridge 107 as shown in FIG. In this case, the optical pickup is the disc cartridge 107 (not shown).
Will be inserted from the opening.

[0012]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
By adopting the configuration of Japanese Patent No. 8059, it is possible to suppress the surface wobbling of the disk substrate itself due to the decrease in rigidity, so that the thickness of the disk substrate is made thin to the thickness that is conventionally considered to cause the surface wobbling. It is possible to realize high density by shortening the wavelength of light and increasing the numerical aperture NA of the objective lens.

However, there is no description about the substrate material of the optical disc 101 in the above publication, and it can be inferred from the contents described that a conventionally used transparent resin substrate is used. However, when a transparent resin substrate is used as the disc substrate, due to its nature, even if the stabilizing plate 102 is provided to suppress the surface wobbling of the disc substrate itself, further thinning of the disc substrate is hindered and the objective lens The numerical aperture NA cannot be increased.

That is, the problem of surface wobbling due to the decrease in the rigidity of the disk substrate can be solved by providing the stabilizing plate 102. However, when the rigidity of the disk substrate decreases, another problem is that the optical pickup 103 is brought closer to it. When
Flapping (vertical movement) occurs on the optical disc 101 around the optical pickup 103.

The optical pickup 103 includes a stabilizing plate 102.
The optical disc 101 is arranged so as to face the optical disc 101 and is close to the optical disc 101 in order to record and reproduce information. At this time, a pressure variation occurs between the optical pickup 103 and the optical disc 101, and the optical disc is accompanied by the pressure variation. Flapping 101 occurs around the optical pickup 103. Optical disc 1 around the optical pickup 103
01 is fluttering, and good recording and reproduction cannot be performed at all.

The resin has a property that the rigidity is rapidly reduced when the thickness is reduced. For example, FIG. 29 shows the relationship between the substrate thickness and the rigidity when a polyethylene terephthalate (PET) substrate is used as the transparent resin substrate. As can be seen from this, when the thickness of the substrate is reduced, the rigidity sharply decreases. In the case of a PET substrate, if the substrate thickness is less than 60 μm, the above-mentioned fluttering occurs, so the substrate thickness is 60 μm
It cannot be thinner than m. As a result, when a transparent resin substrate is used as the disc substrate, there is a limit in increasing the numerical aperture NA of the objective lens.

The same applies to the case of the type of the disc cartridge 107 that accommodates the optical disc 101 shown in FIG. 28. If the rigidity of the optical disc 101 becomes too low, the optical disc 101 may flap around the optical pickup 103 when the optical pickup 103 approaches. However, it becomes difficult to perform good recording and reproduction.

[0018]

In order to solve the above-mentioned problems, a flexible optical disk of the present invention has a resin layer and a metal reflection layer having a concavo-convex pit pattern on a flexible metal substrate. The light-transmitting protective layer is sequentially formed.

In order to solve the above problems, the flexible optical disk of the present invention has a resin layer having an uneven pit pattern and / or an uneven guide groove pattern on a flexible metal substrate. It is characterized in that an optical recording layer and a light transmitting protective layer are sequentially formed.

In the above structure, a flexible metal substrate is used as a substrate (disc substrate) of a flexible optical disc (hereinafter may be simply referred to as an optical disc), and uneven pits are formed on the metal substrate. A resin layer having a pattern or a resin layer having an uneven pit pattern and / or an uneven guide groove pattern is formed to form a disk substrate.

Therefore, the rigidity required for a flexible optical disk can be ensured by the metal substrate formed of the disk substrate and the resin layer. The necessary rigidity referred to here is a rigidity that can maintain a stable rotation operation when the optical disk is mounted in the optical disk device. More specifically, in order to speed up the recording / reproducing of information, the necessary rigidity is required. In order to record and reproduce information, the condensing means (objective) of the optical disk device has a rigidity that enables stable rotation operation even when the optical disk having high properties is rotationally driven at high speed. Rigidity that enables the optical pickup including the lens group) to maintain a stable rotation operation even when pressure fluctuations occur between the optical pickup and the optical disc that occurs when the optical pickup approaches the flexible optical disc. Is.

As described above, in the flexible optical disk of the present invention, since the rigidity itself required for the flexible optical disk can be obtained by the metal substrate, the recording on the side opposite to the metal substrate is performed. Alternatively, when the thickness of the light-transmitting protective layer on which light is incident for reproduction is reduced to shorten the wavelength of light and increase the numerical aperture NA of the objective lens to reduce the light beam spot. Also, it is possible to increase the allowable amount with respect to the tilt of the optical disc. The thickness of the transparent protective film on the light incident side can be made as thin as possible without being restricted by the rigidity and the like required for a flexible optical disk.

Further, since the metal itself has a very high rigidity as compared with the resin, it can be made very thin even if it has a rigidity required for a flexible optical disk.
Not to mention making the optical disc itself thinner,
It is possible to reduce the thickness of the optical disc device.

In the flexible optical disk of the present invention, the resin layer may be formed of an ultraviolet curable resin, and in this case, the film thickness of the resin layer is preferably 1 μm to 50 μm. The fine irregularities on the surface of the metal substrate can be covered with the resin layer, and it does not take a long time to cure the resin layer. A phase change recording medium or a magneto-optical recording medium can be used for the optical recording layer. Further, the light-transmitting protective layer can also be formed from an ultraviolet curable resin.

In the flexible optical disk of the present invention, the rigidity of the metal substrate is 0.005 kgf.
-Mm-0.150 kgf-mm can also be characterized. By adopting a structure in which the rigidity of the metal substrate satisfies this range, it is possible to easily realize the flexible optical disk of the present invention that exhibits the above-described actions and effects.

As the metal substrate, one made of aluminum can be used, and the thickness of the metal substrate in that case is in the range of 22 .mu.m to 66 .mu.m. It is possible to easily realize a flexible optical disc.

Further, as the metal substrate, one made of iron may be used. In this case, the thickness of the metal substrate is set in the range of 15 μm to 45 μm, whereby the above-described action and effect of the present invention can be obtained. It is possible to easily realize a flexible optical disc.

As the metal substrate, one made of copper can be used. In this case, the thickness of the metal substrate is in the range of 18 μm to 53 μm. It is possible to easily realize a flexible optical disc.

Further, as the metal substrate, one made of nickel may be used. In this case, the thickness of the metal substrate is set in the range of 15 μm to 44 μm. It is possible to easily realize a flexible optical disc.

Further, as the metal substrate, one made of titanium can be used, and in this case, the thickness of the metal substrate is set in the range of 18 μm to 55 μm, whereby the above-described action and effect of the present invention can be obtained. It is possible to easily realize a flexible optical disc.

As the metal substrate, a substrate made of an iron alloy containing iron as a main component can be used, and one of them is stainless steel made of Fe, Cr and Ni. The thickness of the substrate is 14
By setting the thickness in the range of μm to 43 μm, it is possible to easily realize the flexible optical disk of the present invention that exhibits the above-described actions and effects.

Further, as the metal substrate, one made of a titanium alloy containing titanium as a main component can also be used, and a titanium alloy made of Ti, Al and V can be mentioned as one type thereof. By setting the thickness of the metal substrate to be in the range of 17 μm to 51 μm, it is possible to easily realize the flexible optical disk of the present invention having the above-described actions and effects.

Further, as the metal substrate, one made of an aluminum alloy containing aluminum as a main component can be used, and one example thereof is duralumin made of Al, Cu and Mg, and the metal substrate in that case. By setting the thickness to be in the range of 22 μm to 65 μm, it is possible to easily realize a flexible optical disk having the flexibility of the present invention, which exhibits the above-described actions and effects.

Further, as the metal substrate, one made of a copper alloy containing copper as a main component can be used, and phosphor bronze made of Cu, Sn, and P can be mentioned as one of them, and in that case. The thickness of the metal substrate is 18 μm
By setting the thickness in the range of up to 55 μm, it is possible to easily realize the flexible optical disk of the present invention that exhibits the above-described actions and effects.

The flexible optical disk cartridge of the present invention is obtained by inserting the flexible optical disk of the present invention into an optical disk cartridge case. In the case of a flexible optical disc, a stabilizing plate is required at a position facing the optical disc for stable rotation. According to this, the inner wall surface of the optical disc cartridge case facing the optical disc is a stabilizing plate. Since it does not need to provide a stabilizing plate on the optical disc device side, the configuration of the optical disc device can be simplified as compared with the case where the stabilizing plate is provided.

Further, as described above, the flexible optical disc of the present invention uses a flexible metal substrate as the disc substrate, and an uneven pit pattern and an uneven guide groove pattern are formed on the surface of the metal substrate. The optical disc cartridge itself is sufficiently thin because the optical disc itself has a sufficiently thin constitution as compared with the constitution of the disc substrate made of only resin because the resin substrate is formed as a disc substrate. is there.

Further, in the optical disk cartridge of the present invention, the distance between both inner wall surfaces facing the optical disk in the optical disk cartridge case is set so that the optical disk stably rotates at an intermediate position between both inner wall surfaces. Is more preferable.

When the distance between both inner wall surfaces facing the optical disk of the optical disk cartridge case is wide, the flexible optical disk uses the lower inner wall surface as a stabilizing plate, but in this case, external disturbance such as impact is generated. Is added,
The stable rotation of the optical disc is hindered, and the optical disc fluctuates up and down.

On the other hand, as described above, the distance between both inner wall surfaces of the optical disk cartridge case is set so that the optical disk stably rotates at an intermediate position between the both inner wall surfaces. It can be used as a stabilizing plate to rotate, and can be configured to be more resistant to disturbance.

In this case, the distance between both inner wall surfaces of the optical disk cartridge case is t1, and the thickness of the optical disk is t2.
In this case, by designing t1-t2 to be 20 μm to 400 μm, it is possible to easily obtain the above-mentioned optical disc cartridge that is resistant to disturbance.

As the optical disk cartridge,
Since the optical disc cartridge case is made of metal, the thickness of the cartridge case itself can be made thin, so that the optical disc cartridge can be made thinner and the optical disc device can be made thinner.

The optical disk device of the present invention is an optical disk device for recording or reproducing data on or from the above-mentioned flexible optical disk of the present invention or the optical disk cartridge of the present invention. It is characterized in that the metal layer or the optical recording layer is irradiated with light from the protective layer side.

With such a structure, the optical disk and the optical disk cartridge of the present invention described above are
A device capable of recording or reproducing information can be provided.

[0044]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a flexible optical disk and an optical disk device according to the present invention will be described below with reference to FIG.
~ It demonstrates, referring to FIG.

First, a flexible optical disk will be described with reference to FIGS. In the following, a flexible optical disc may be simply referred to as an optical disc.

FIG. 1 is a schematic view of an optical disk 1 having flexibility, and FIG. 2 is a partial sectional view of the optical disk 1.

The optical disc 1 is of a type capable of recording / reproducing and a ROM type capable of only reproducing. The optical disc 1 of the type capable of recording / reproducing has a flexible metal substrate 2 and the metal substrate. Resin layer 3 having an uneven pit pattern and / or an uneven guide groove pattern formed on
And a recording medium layer (optical recording layer) formed on the resin layer 3
4 and a light-transmitting protective layer 5 for protecting the recording medium layer 4. On the other hand, RO that is only played back
The M type optical disc 1 includes a flexible metal substrate 2
A resin layer 3 ′ having an uneven pit pattern formed on the metal substrate 2, a metal reflection layer 4 ′ formed on the resin layer 3 ′, and a metal reflection layer 4 ′ for protecting the metal reflection layer 4 ′. It is composed of a light-transmitting protective layer 5.

FIG. 3 is a diagram showing a method of forming the optical disc 1 called the 2P method. After the metal substrate 2 is placed on the mirror plate 6 and the ultraviolet curable resin 3a to be the resin layer 3 (or the resin layer 3 ′) is applied onto the metal substrate 2,
A transparent stamper 7 having an uneven pit pattern and / or an uneven guide groove pattern (or a transparent stamper 7'having an uneven pit pattern) is pressure-bonded in the direction of the mirror plate 6 and ultraviolet rays 8 are irradiated from the transparent stamper 7 (7 ') side. Then, the ultraviolet curable resin 3a applied on the metal substrate 2 is cured. Then, by peeling the ultraviolet curable resin 3a that hardens the metal substrate 2 from the transparent stamper 7 (7 ') and the mirror surface plate 6, the uneven pit pattern and / or the unevenness on the metal substrate 2 shown in FIG. Resin layer 3 having guide groove pattern
(Or the resin layer 3 ′ having the concave and convex pit pattern) is formed, and the substrate of the optical disc 1 (disc substrate) is completed. Here, as the transparent stamper 7 (7 ′),
It is desirable that the concave and convex pit pattern and / or the convex guide groove pattern (or the concave and convex pit pattern) be formed on the surface of the glass substrate by dry etching.

5 and 6 show the optical disc 1 shown in FIG.
FIG. 3 is a partial cross-sectional perspective view showing a partially enlarged substrate of FIG. On the surface of the resin layer 3 on which the optical disc 1 is recordable and reproducible, as shown in FIG. 5, a guide groove (concavo-convex guide groove pattern) 9 for guiding a light beam for recording and reproduction is spirally formed. (The resin layer 3 in FIG. 5 is a type in which only the uneven guide groove pattern is formed). On the other hand, as shown in FIG. 6, pits (concave and convex pit patterns) 10 forming information are spirally formed on the surface of the resin layer 3'of the ROM type in which the optical disc 1 is only read. .

In the rewritable optical disk of the present invention, an optical disk of a type in which a tracking signal is obtained along the concave and convex guide grooves and an address signal is obtained by the concave and convex pits, and both the tracking signal and the address signal are obtained only by the concave and convex guide grooves. The present invention is applicable to an optical disc of a type called a wobble guide groove type and an optical disc of a type called a sample servo type in which both a tracking signal and an address signal are obtained only by uneven pits.

The metal substrate 2 is made of metal and is flexible and has a small thickness. The rigidity of a flexible metal substrate is 0.005 kgf.
-Mm-0.150 kgf-mm is confirmed, More preferably, it is 0.008 kgf-mm-0.
It has also been confirmed that it is 122 kgf · mm. In addition,
The reason will be described later.

Within the range of the rigidity, the material is, for example, a substrate made of a single metal such as aluminum, iron, copper, nickel and titanium, and an alloy containing these metals as a main component, for example, stainless steel. Examples thereof include iron alloys, titanium alloys, aluminum alloys represented by duralumin, and copper alloys represented by phosphor bronze.

When the metal substrate 2 made of aluminum is used, the thickness thereof is 22 μm to 66 μm.
By setting the range to m, it is possible to obtain the rigidity required for the flexible optical disc 1. Further, it is more preferable that the thickness is in the range of 25 μm to 61 μm.

When a metal substrate 2 made of iron is used, the thickness of the metal substrate 2 is in the range of 15 μm to 45 μm, whereby the rigidity required for the flexible optical disk 1 can be obtained. Further, it is more preferable that the thickness is in the range of 17 μm to 42 μm.

When a metal substrate 2 made of copper is used, its thickness is 18 μm to 53 μm.
Within the range, the rigidity required for the flexible optical disc 1 can be obtained. Further, it is more preferable that the thickness is in the range of 21 μm to 50 μm.

When the metal substrate 2 is made of nickel, its thickness is 15 μm to 4 μm.
By setting the thickness in the range of 4 μm, the rigidity required for the flexible optical disk 1 can be obtained. Moreover, it is more preferable that the thickness is in the range of 17 μm to 41 μm.

When a metal substrate 2 made of titanium is used, its thickness is 18 μm to 55 μm.
The optical disc 1 having flexibility in the range of μm
The required rigidity can be obtained. Further, it is more preferable that the thickness is in the range of 21 μm to 52 μm.

Further, as the metal substrate 2, Fe, Cr and N are used.
When stainless steel composed of i is used, the rigidity required for the flexible optical disc 1 can be obtained by setting the thickness in the range of 14 μm to 43 μm. Further, it is more preferable that the thickness is in the range of 16 μm to 40 μm.

Further, as the metal substrate 2, Ti, Al and V
When a titanium alloy composed of and is used, the rigidity required for the flexible optical disc 1 can be obtained by setting the thickness in the range of 17 μm to 51 μm. Further, it is more preferable that the thickness is in the range of 20 μm to 47 μm.

As the metal substrate 2, Al, Cu and M are used.
When duralumin consisting of g is used, the thickness thereof is in the range of 22 μm to 65 μm, whereby the rigidity required for the flexible optical disc 1 can be obtained. Further, it is more preferable that the thickness is in the range of 25 μm to 60 μm.

As the metal substrate, Cu, Sn and P are used.
When phosphor bronze consisting of and is used, the thickness is
By setting the thickness in the range of 18 μm to 55 μm, the rigidity required for the flexible optical disc 1 can be obtained.
Moreover, it is more preferable that the thickness is in the range of 22 μm to 52 μm.

Resin layer 3 formed on the metal substrate 2
The layer thickness of 3 ′ is preferably 1 μm or more and 50 μm or less. The fine unevenness defects on the surface of the metal substrate 2 are covered by the resin layers 3 3 ′, and the unevenness pits on the surface of the transparent stamper 7 having no unevenness defects on the surface of the resin layers 3 3 ′. The pattern and / or the uneven guide groove pattern will be transferred, but if the layer thickness of the resin layers 3 and 3 ′ becomes smaller than 1 μm, fine uneven defects on the surface of the metal substrate 2 will be transferred to the resin. The layers 3 and 3'cannot be covered, and the recording / reproducing error due to the uneven defect increases. Further, when the layer thickness of the resin layer 3.3 ′ is larger than 50 μm, it takes a long time to cure the resin layer 3.3 ′, and the process time for manufacturing the optical disc becomes long, and This will increase costs.

Recording medium layer 4 formed on the resin layer 3
As the recording medium, a rewritable phase change recording medium, a magneto-optical recording medium, or a write-once type dye recording medium can be used. An Al alloy can be used as the metal reflective layer 4 ′ formed on the resin layer 3 ′ having only the concave and convex pit pattern formed on the surface of the ROM type.

FIG. 7 and FIG. 8 are enlarged cross-sectional views of the optical disc 1 when a phase change recording medium and a magneto-optical recording medium are used as the recording medium of the recording medium layer 4, respectively.

An optical disc 1 using the phase change recording medium shown in FIG. 7 has a resin layer 3 having guide grooves 9 on a metal substrate 2.
Are formed by the 2P method, and then Al is formed as the recording medium layer 4.
Reflective film 11, a ZnS-SiO ₂ interference layer 12, SiN protective layer 13, GeSbTe phase change recording layer 14, SiN protective layer 15, ZnS-SiO ₂ interference layer 16 are sequentially formed by sputtering, and further, an ultraviolet curable resin The light-transmitting protective layer 5 is formed.

The optical disc 1 using the magneto-optical recording medium shown in FIG. 8 is capable of magnetic super-resolution reproduction after the resin layer 3 having the guide groove 9 is formed on the metal substrate 2 by the 2P method. As the recording medium layer 4, AgTi heat dissipation layer 17, Al
N protective layer 18, TbFeCo recording layer 19, Al nonmagnetic intermediate layer 20, GdFeCo reproducing layer 21, AlN interference layer 22.
Are sequentially formed by sputtering, and a transparent protective layer 5 made of an ultraviolet curable resin is further formed.

Since the light-transmitting protective layer 5 is irradiated with light for recording from the light-transmitting protective layer 5 side, it is necessary that at least light can be transmitted in addition to the function as a protective layer. is there. As the material of the light transmitting protective layer 5, a resin layer such as a resin sheet adhesive layer can be used in addition to the ultraviolet curable resin layer. When the light-transmitting protective layer 5 is formed by adhering a resin sheet, the thickness of the resin sheet can be controlled with high precision, so that the light-condensing characteristics on the recording medium layer 4 or the metal reflective layer 4 ′ can be improved. It becomes possible to make it good.

Further, by forming a thin film capable of transmitting light and having a high hardness, for example, a SiC thin film, a SiN thin film, or a TiO ₂ thin film on the surface of the light transmissive protective layer 5, the light incident surface of the optical disc 1 is exposed. It is possible to suppress an increase in errors due to the occurrence of scratches. In addition, the light-transmitting protective layer 5
It is also possible to directly form a thin film which is transparent to light and has a high hardness, for example, a SiC thin film, a SiN thin film or a TiO ₂ thin film.

Next, with reference to FIGS. 9 to 11, an optical disk device capable of recording and reproducing information on the optical disk 1 using the flexible metal substrate 2 will be described.

FIG. 9 shows a schematic diagram of an optical disk device. This optical disc apparatus handles a read-only ROM type optical disc 1 and a rewritable optical disc 1 using a phase change recording medium as a recording medium of a recording medium layer 4.

The optical disk 1 is fixed to the spindle 24 via the center hub 23 and is rotationally driven. Here, the stabilizing plate 25 is arranged so as to face the optical disc 1, and a negative pressure state is created between the optical disc 1 and the stabilizing plate 25 as the optical disc 1 rotates, so that the optical disc 1 and the stabilizing plate 25 are separated from each other. An air bearing is formed between the optical disc 1 and the optical disc 1, and the optical disc 1 rotates while maintaining a constant distance from the stabilizing plate 25. An optical pickup 32 is arranged on the stabilizing plate 25 so as to be movable by a driving means (not shown) in the radial direction of the optical disc 1 in which a first hole 35 for fixing the optical disc 1 to the spindle 24 is provided. Has been done. The optical pickup 32 includes a light emitting element (not shown) for recording / reproducing, a control light receiving element (not shown) for tracking and focusing, and a reproduction signal detecting light receiving element (not shown). The element unit 26, a mirror 29 that guides the light beam 27 to the condensing unit 28, and a condensing unit 28 that is supported by a biaxial actuator 30 so as to be driven in the focus direction and the track direction.

Driving of the light emitting / receiving element portion 26 and the biaxial actuator 30 is controlled by a signal processing circuit 31. The signal processing circuit 31 controls the power of the light emitting element of the light emitting and receiving element section 26 and generates a reproduction signal of recorded information from the output from the reproduction signal detecting light receiving element. Further, the signal processing circuit 31 drives the biaxial actuator 30 based on the output of the control light-receiving element of the light-emitting / light-receiving element section 26 to generate the reproduction signal, and displaces the light-collecting means 28. Focusing is performed so that the light beam 27 that has passed through is incident from the side of the light-transmitting protective layer 5 and is focused on the recording medium 4, and the focused spot relatively moves along the guide groove 9. It is possible to perform tracking and record / reproduce information.

In the case of the ROM type optical disk 1, focusing is performed in the same manner as described above so that the light beam 27 is focused on the metal reflection layer 4 ', and the optical disk 1
Information is reproduced by performing tracking so that the focused spot relatively moves along the pit 10 on the resin layer 3 '.

In the above optical disk device, in order to reduce the diameter of the light beam spot, a semiconductor laser having a wavelength of 350 nm to 650 nm is used as a light emitting element, and the numerical aperture NA of the condensing means 28 is 0.70 to 1.00. Is desirable. Note that although FIG. 9 shows that the light collecting means 28 is composed of one objective lens, when the numerical aperture is increased, the light collecting means 28 is configured by two or more objective lens groups. Therefore, it is possible to easily manufacture the light collecting means having a large numerical aperture.

FIG. 10 shows a schematic view of another optical disk device. This optical disk device is a read-only ROM
Type optical disc 1 and rewritable optical disc 1 using a phase change recording medium as the recording medium of the recording medium layer 4.
In addition, the present invention deals with a rewritable optical disc using a magneto-optical recording medium as the recording medium of the recording medium layer 4.

Since the main structure is the same as that of the optical disk device shown in FIG. 9, members having the same functions are designated by the same reference numerals and the description thereof will be omitted. The optical disk device shown in FIG. 10 has a configuration in which the optical disk device of FIG. 9 is further provided with a magnetic head 33 for applying a recording magnetic field to the magneto-optical recording medium.

When a magneto-optical recording medium is used as the recording medium in the recording medium layer 4, it is necessary to apply a recording magnetic field for recording, and it is integrated with the optical pickup 32 at a position facing the light converging means 28. A magnetic head 33 for applying a recording magnetic field supported by a movable suspension 36 is arranged. The magnetic head 33 can be mounted on a slider so that the magnetic head 33 travels stably with respect to the optical disc 1. Since the magnetic head 33 is arranged close to the metal substrate 2 side of the optical disk 1, the stabilizing plate 35 is further provided with a second hole 34 into which the magnetic head 33 can be inserted. FIG. 11 is a plan view of the stabilizing plate 25. A second hole 34 into which the magnetic head 33 can be inserted is provided at a position corresponding to the moving direction of the magnetic head 33, in this case, the radial direction of the optical disk 1. ing.

Here, the magnetic head 33 is arranged closer to the suspension 36 from the metal substrate side, but since the thickness of the metal substrate is thin, the magnetic field strength generated from the magnetic head 33 is not greatly attenuated for recording. A recording magnetic field having a sufficient intensity can be applied to the recording medium layer 4 by reaching the medium layer 4.

Further, the stabilizing plate 35 which realizes stable rotation of the optical disk 1 using the flexible metal substrate 2 is provided.
Need not be provided in the optical disk device, but the optical disk 1 can be housed in an optical disk cartridge case (hereinafter, cartridge case) and the inner wall surface of the cartridge case can be used as a stabilizing plate.

Next, referring to FIGS. 12 to 15, an optical disk cartridge in which the flexible optical disk 1 is housed in a cartridge case, and an optical disk device capable of recording / reproducing information on / from the optical disk cartridge are described. Will be described.

FIG. 12 shows an optical disk cartridge 50 in which the optical disk 1 is housed in a cartridge case 37.
FIG. 9 is a cross-sectional view of the inner wall surface of the cartridge case 37 used as a stabilizing plate. FIG. 13 shows a plan view of the optical disk cartridge 50. FIG. 12 is a cross section taken along the line AA ′ of FIG. Further, FIG. 14 shows an optical disk cartridge 50 having a BB ′ cross section of FIG.
And an optical disk device that handles the optical disk cartridge 50.

As the material of the cartridge case 37,
Resins such as polycarbonate and metallic materials such as stainless steel and duralumin can be used. When resin is selected as the material, it is necessary to have a certain thickness in order to obtain the rigidity required for the cartridge case 37. On the other hand, when a metal material having a rigidity higher than that of resin is used, even if the wall thickness is reduced, the cartridge case 37
As a result, the required rigidity can be obtained, and the optical disc cartridge 50, and thus the optical disc device, can be made even thinner.

Inner wall surface 3 on the upper side of the cartridge case 37
8, the optical disc 1 fixed to the spindle 24 via the center hub 25 stably rotates with the lower inner wall surface 39 as a stabilizing plate, as shown in FIG. Is set. If the optical disc 1 rotates stably with the lower inner wall surface 39 as a stabilizing plate, this space is required to reduce the thickness of the optical disc cartridge 50 and thus the optical disc device as a whole.
The smaller the better.

As shown in FIGS. 13 and 14, in the cartridge case 37, in addition to the first opening 40 for fixing the optical disk 1 to the spindle 24, the condensing means 28 of the optical pickup 32 is provided. A second opening 41 for disposing the optical disc 1 close to the optical disc 1 is provided.

Further, as shown in FIG. 13, a slide shutter 42 that can be opened and closed is provided in the first opening 40 and the second opening 41. The slide shutter 42 is used in an optical disk cartridge 50 in an optical disk device.
Is attached, the first opening 40 and the second opening 41
Are opened, and the first opening 40 and the second opening 41 are closed when the optical disk cartridge 50 is taken out from the optical disk device. By providing the slide shutter 42, it is possible to prevent dust from adhering to the optical disc 1.

The structure of the optical disk device shown in FIG. 14 for handling such an optical disk cartridge 50 is almost the same as that of the optical disk device shown in FIG. 9 except that the stabilizing plate 25 is not provided. The members having a function are designated by the same reference numerals and the description thereof will be omitted.

FIG. 15 shows the cartridge case 3
7'shows a magneto-optical recording type optical disc cartridge 50 'in which an optical disc 1 using a magneto-optical recording medium is accommodated in a recording medium layer 4, and an optical disc device which handles the optical disc cartridge 50'. 15, the cross section of the optical disk cartridge 50 'is the same as the cross section of BB' in FIG. 13 as in the case of FIG.

When the recording medium layer 4 is the optical disc 1 made of a magneto-optical recording medium, a recording magnetic field is required for recording, and as shown in FIG. 15, the cartridge case 37 'is used.
Is provided with a third opening 43 for arranging the magnetic head 33 for generating a recording magnetic field close to the metal substrate 2 side of the optical disc 1 at a position facing the second opening 41. ing. In this case, it is desirable that the slide shutter 42 that can be opened and closed be provided so as to cover the first opening 40, the second opening 41, and the third opening 43.

The structure of the optical disk device shown in FIG. 15 for handling such an optical disk cartridge 50 'is almost the same as the optical disk device shown in FIG. 10 except that the stabilizing plate 25 is not provided. Members having the same function are designated by the same reference numerals, and description thereof will be omitted.

Next, referring to FIGS. 16 and 17, an optical disk cartridge having another structure in which the optical disk 1 is housed in a cartridge case, and an optical disk device capable of recording / reproducing information on / from the optical disk cartridge are described. explain.

The optical disk cartridges 50 and 50 'shown in FIGS. 12 to 15 are the cartridge cases 37 and 3.
By using the inner wall surface 39 on the lower side of 7'as a stabilizing plate, stable rotation of the optical disc 1 is realized.
However, in the case of this configuration, since the optical disc 1 and the inner wall surface 38 on the upper side of the cartridge case 37, 37 'are separated from each other, the optical disc 1 can be stably rotated when a disturbance such as an impact is applied to the optical disc device from the outside. Is blocked,
Flapping up and down of the optical disc 1 will occur.

In order to eliminate such a problem, in the case of the optical disk cartridge 50a shown in FIG. 16, the inner wall surface 38 on the upper side and the inner wall surface 39 on the lower side of the cartridge case 37a.
By narrowing the space between the cartridge case 5
Both inner wall surfaces 38 and 39 of 3 are used as a stabilizing plate of the optical disc 1. The inner wall surface 38
Only the interval of 39 is narrow, and the material and required rigidity are the same as those of the cartridge case 37 described above.

By narrowing the gap between the inner wall surface 38 on the upper side and the inner wall surface 39 on the lower side of the cartridge case 37a, the optical disk 1 is made into the optical disk 1 and the inner wall surface 38 on the upper side.
So as to balance the air pressure between the optical disk 1 and the lower inner wall surface 39.
・ It will rotate stably at the intermediate position of 39.

In such a state, when a disturbance such as a shock is applied and the optical disk 1 tries to approach the upper inner wall surface 38, the air pressure between the optical disk 1 and the upper inner wall surface 38 increases, and the optical disk 1 is pushed back to the stable rotation position. Therefore, the fluttering of the optical disk 1 is suppressed, and the optical disk 1 always rotates stably at the intermediate position between the inner wall surfaces 38 and 39.

As a design of the optical disk cartridge 50a that is strong against such a disturbance such as impact, when the number of revolutions of the optical disk 1 is 1000 rpm to 4000 rpm, the inner wall surfaces 38 of the optical disk 1 and the cartridge case 37a.
It has been confirmed that the distance from the gap 39 should be 10 μm to 200 μm. By satisfying the above-mentioned interval, the inner wall surfaces 38, 39 of the cartridge case 37a respectively act as stabilizing plates, and air bearings are formed between the flexible optical disk 1 and the inner wall surfaces 38, 39. 1 without colliding with the inner wall surfaces 38 and 39,
It can be stably rotated.

Further, more preferably, the inner wall surfaces 38.3 of the optical disk 1 and the cartridge case 37a are in the range of 1500 rpm to 3000 rpm of the optical disk 1.
That is, the distance from the groove 9 is set to 20 μm to 100 μm.

Optical disk 1 and cartridge case 37a
When the distance between the inner wall surfaces 38 and 39 is small, the optical disk 1 may collide with the inner wall surfaces 38 and 39 due to a disturbance factor such as vibration, and the surface of the optical disk 1 may be damaged. By setting the interval to 20 μm or more, such collision can be surely avoided. Further, when the distance between the optical disk 1 and the inner wall surfaces 38, 39 of the cartridge case 37a is wide, fluttering of the optical disk 1 is likely to occur due to a disturbance factor such as vibration.
By setting the thickness to 0 μm or less, such flapping can be prevented.

Optical disk 1 and cartridge case 37a
10 μm to 200 μm between the inner wall surfaces 38 and 39 of
In order to achieve the above, when the distance between the inner wall surfaces 38 and 39 of the cartridge case 37a is t1 and the thickness of the optical disk 1 is t2, t1-t2 may be 20 μm to 400 μm. In addition, a more preferable range of 20 μm to 100
To obtain μm, t1-t2 is 40 μm to 200 μm.
It should be m.

The optical disk device shown in FIG. 16 which handles such an optical disk cartridge 50a is the same as the optical disk device shown in FIG.

Further, FIG. 17 shows the cartridge case 37'a as in the optical disk cartridge 50a of FIG.
A magneto-optical recording type optical disk cartridge 50'a that is strong against external disturbances such as impacts and uses the both inner wall surfaces 38 and 39 as stabilizing plates, and an optical disk device that handles the optical disk cartridge 50'a.

The cartridge case 37'a has an inner wall surface 38.
The space between the inner wall surface 39 and the lower inner wall surface 39 is designed to be narrow, and the optical disk 1 using the magneto-optical recording medium in the recording medium layer 4 is housed therein. In the case of the optical disc 1 in which the recording medium layer 4 is a magneto-optical recording medium, a recording magnetic field for recording is necessary, and as shown in FIG. 17, the cartridge case 37′a is for generating a recording magnetic field. A third opening 43 for disposing the magnetic head 33 close to the metal substrate 2 side of the optical disk 1 is provided at a position facing the second opening 41. The inner wall surface 38.3
The intervals of 9 are the same as in the case of the cartridge case 37a described above, and the material and the required rigidity are
It is the same as the cartridge case 37 described above.

Further, the optical disk device shown in FIG. 17 which handles such an optical disk cartridge 50'a is shown in FIG.
It is the same as the optical disk device shown in FIG.

[0103]

EXAMPLES The present invention will be specifically described below with reference to examples.

Example 1 As the metal substrate 2 constituting the disk substrate, a stainless steel (Fe ₇₆ Cr ₁₇ Ni ₇ ) substrate having a diameter of 50 mm and a thickness of 12 μm (hereinafter, a metal substrate made of stainless steel is referred to as a stainless steel substrate). Using
A resin layer 3 ′ having a layer thickness of 5 μm having a concavo-convex pit pattern is formed on the stainless steel substrate 2 by a 2P method, and a metal reflective layer 4 ′ made of an AlTi alloy is formed by sputtering, and then used as a light-transmitting protective layer 5. By forming an ultraviolet curable resin layer having a layer thickness of 5 μm by the 2P method, a diameter of 50 m can be obtained.
m ROM type optical disk 1 was produced. Similarly, the thickness of the stainless steel substrate 2 is changed variously to obtain the diameter 50
A plurality of mm type ROM type optical disks 1 were formed.

The metal substrate 2 has a diameter of 130 m.
m, 12 μm thick made of stainless steel (Fe ₇₆ Cr ₁₇ N
i ₇ ), the resin layer 3 ′, the metal reflection layer 4 ′, and the light-transmitting protective layer 5 are formed on the stainless steel substrate 2 by the same procedure as in the case where the diameter is 50 mm and the diameter is 130 mm.
A ROM type optical disk 1 was manufactured. In this case as well, in the same manner, the thickness of the stainless steel substrate 2 was variously changed to form a plurality of ROM type optical disks 1 having a diameter of 130 mm.

The optical disc 1 having a diameter of 50 mm has a diameter of 13
Also in the 0 mm optical disc 1, the uneven pit row of the resin layer 3 ′ was spirally formed with a track pitch of 0.3 μm, and a pit row having a pit diameter of 0.15 μm, a pit period of 0.3 μm, and a pit depth of 25 nm was formed. It is a thing.

After the center hub 23 (see FIG. 9) is adhered and fixed to each of the optical discs 1 thus formed,
The optical disc device shown in FIG. 9 was mounted and rotated at 2000 rpm to measure the focus error amount.

In the optical disc 1 having a diameter of 50 mm,
The focus error amount was measured at an inner peripheral position having a diameter of 22 mm (11 mm from the center) and an outer peripheral position having a diameter of 44 mm (22 mm from the center). On the other hand, in the optical disc 1 having a diameter of 130 mm, the diameter 6
An inner peripheral position which is a position of 0 mm (30 mm from the center),
The focus error amount was measured at the outer peripheral position, which was a position with a diameter of 120 mm (60 mm from the center).

Further, a semiconductor laser having a wavelength of 405 nm was used as the issuing element of the optical disk device used here, and a second group objective lens having an NA of 0.85 was used as the focusing means 28.

Table 1 shows the measurement result of the focus error amount of each optical disc 1 having a diameter of 50 mm, and Table 2 shows the measurement result of the focus error amount of each optical disc 1 having a diameter of 130 mm.

[0111]

[Table 1]

[0112]

[Table 2]

From Table 1, in the case of the optical disc 1 having a diameter of 50 mm, the thickness of the stainless steel substrate 2 is 14 μm to 43 μm.
The focus error in the focus direction is ±
It is less than 0.2 μm, which shows that the focusing is good. When there is a focus error of ± 0.2 μm or more in the focus direction, the expansion of the light beam spot diameter becomes remarkable and focusing failure occurs. Therefore, the allowable value of the focus error amount is set to less than ± 0.2 μm.
Actually, the concave-convex pit information could be accurately reproduced for the optical disc 1 in which the thickness of the stainless steel substrate 2 was within the range.

From Table 2, also in the case of the optical disc 1 having a diameter of 130 mm, the thickness of the stainless steel substrate 2 is 1 as well.
Under the condition of 4 μm to 43 μm, the focus error in the focus direction is less than ± 0.2 μm, which shows that the focusing is good. Actually, the concave-convex pit information could be accurately reproduced for the optical disc 1 in which the thickness of the stainless steel substrate 2 was within the range.

Here, regardless of the diameter size, the reason why the focus error amount exceeds the allowable value when the thickness of the stainless steel substrate 2 is thinner than 14 μm is that fluttering occurs around the optical pickup 32 when it approaches. This is because On the contrary, the thickness of the stainless steel substrate 2 is 4
The reason why the focus error amount exceeds the allowable value when it is thicker than 3 μm is that the optical disc 1 will rotate stably at a position determined by the pressure state between the optical disc 1 and the stabilizing plate 25 regardless of the diameter size. This is because, due to the loss of the portability of the optical disc 1, the force of the optical disc 1 attempting to rotate while maintaining rigidity collides with each other to cause flapping of the optical disc 1.

From this result, at least a diameter of 50 mm
In the optical disc 1 having a diameter of 130 mm, it can be said that by setting the thickness of the stainless steel substrate 2 to 14 μm to 43 μm, a focus error amount of less than 0.2 μm is realized, and good focusing is possible.

Therefore, next, the rigidity is determined when the thickness of the stainless steel substrate 2 is set to 14 μm to 43 μm.

Rigidity δ of stainless steel substrate 2 (kgf · m
m) is the Young's modulus E (kgf / mm ² ) of stainless steel,
It can be calculated by the following equation (1) using the Poisson's ratio v and the thickness h (mm).

Δ = E · h ³ (1-v ² ) / 12 (1) In Equation (1), Young's modulus of stainless steel E = 25000 kg
Substituting f / mm ² and Poisson's ratio v = 0.29 of stainless steel, the rigidity δ of the stainless steel substrate 2 is calculated as follows.
The graph of FIG. 18 was obtained as a function of thickness.

From the graph, the stainless steel substrate 2 has a thickness of 1
The rigidity δ in the case of 4 μm to 43 μm is 0.005 kgf
-It turns out that it becomes mm-0.15 kgf-mm.

From this, at least the diameter of 50 to 13
In the 0 mm optical disc 1, the metal substrate 2 has a rigidity of 0.005 kgf · mm to 0.15 kgf ·
It can be said that stable focusing becomes possible and the concave-convex pit information of the ROM type optical disc 1 can be reproduced within the range of mm.

Further, more specifically, the focus error amount is ± less than ± 0.2 μm as described above.
It is more preferable that the thickness is 0.1 μm or less. By setting the focus error amount to ± 0.1 μm or less, it is possible to reduce the drive amount of the condensing unit 28 required for focusing, and it is possible to make the biaxial actuator 30 that drives the condensing unit 28 thin. It will be possible.

According to Table 1 and Table 2, the thickness of the stainless steel substrate 2 for which the focus error amount is ± 0.1 μm or less is 16
It can be seen that the thickness is from μm to 40 μm. Therefore, in the optical disc 1 having a diameter of at least 50 to 130 mm, the metal substrate 2 has a rigidity of 0.008 kgf · mm to 0.
It can be said that 122 kgf · mm is more desirable.

Incidentally, in the above optical disc 1, the metal
The thickness of the reflecting layer 4 ′ is about several tens of nm, and the thickness of the metal substrate 2 is
It is much thinner than that of the optical disc and has a shadow on the rigidity of the optical disc 1.
The sound is considered to be almost nonexistent. Also, for the 2P method
The resin layer 3'formed by
The transient protective layer 5 has a Young's modulus of 230 kgf · mm. ²
Is a value that is two orders of magnitude smaller than the Young's modulus of the metal substrate 2.
Therefore, the influence on the rigidity of the optical disc 1 is extremely small.
It is visible. Therefore, here the metal reflective layer
Ignoring the presence of 4 ', resin layer 3', and light-transmitting protective layer 5
Then, the rigidity of the metal substrate 2 is treated as the rigidity of the optical disk 1.
ing.

[Embodiment 2] Next, for each of the two types of optical disks 1 having a diameter of 50 mm and a diameter of 130 mm prepared in Embodiment 1, at the lower limit of 14 μm and the upper limit of 43 μm of the thickness range of the stainless steel substrate 2 which can perform good focusing, It was investigated how the focus error amount at the inner peripheral position and the outer peripheral position changed when the rotation speed of the optical disk 1 was changed. The inner peripheral position and the outer peripheral position where the focus error amount is measured in the optical disc 1 of each size are the same as those in the first embodiment.

Table 3 shows the result of measuring the focus error amount.
~ Shown in Table 6.

[0127]

[Table 3]

[0128]

[Table 4]

[0129]

[Table 5]

[0130]

[Table 6]

Table 3 shows the measurement results of the optical disc 1 having a diameter of 50 mm and the stainless substrate 2 having a lower limit of 14 μm.
Has a diameter of 50 mm and the upper limit of the thickness of the stainless steel substrate 2 is 43 μ.
It is a measurement result of the optical disc 1 of m. Table 5 shows the measurement results of the optical disc 1 having a diameter of 130 mm and the stainless steel substrate 2 having a lower limit of 14 μm, and Table 6 shows the measurement results of the optical disc 1 having a diameter of 130 mm and the stainless steel substrate 2 having an upper thickness of 43 μm.

As can be seen from Tables 3 to 6, regardless of the diameter size and the thickness of the stainless steel substrate 2, when the rotation speed (rotation speed) is 1000 rpm, the focus error amount at the outer peripheral position is 0.2 μm or more, Stable focusing is difficult. Therefore, from this, it can be said that it is necessary to set the rotation speed to at least 1500 rpm or more.

The thickness of the stainless steel substrate 2 is 43 μm.
In this case, stable focusing can be realized regardless of the positions of the inner circumference and the outer circumference even if the rotation speed is increased to 6000 rpm, but when the thickness of the stainless steel substrate 2 is 14 μm, the optical disc 1 having a diameter of 50 mm is used. , A focus error of 0.2 μm or more occurred at a rotation speed of 4000 rpm, and the optical disc 1 with a diameter of 130 mm was
In this case, a focus error of 0.2 μm or more occurs at a rotation speed of 3000 rpm. From this, the rotation speed of the optical disk 1 is at least 1500 rpm.
It can be said that the above is necessary.

[Embodiment 3] Instead of the stainless steel substrate 2 described in Embodiment 1, a metal substrate 2 made of aluminum (hereinafter, aluminum substrate 2) can be used.

Therefore, here, the rigidity δ of the metal substrate 2 obtained in Example 1 is 0.005 kgf · mm to 0.15.
The thickness of the aluminum substrate 2 having a value of kgf · mm was determined.

Young's modulus of aluminum E = 7030 kg
f / mm ² , Poisson's ratio of aluminum v = 0.345
Is substituted into the equation (1), the rigidity δ of the aluminum substrate 2 is
The graph of FIG. 19 was obtained as a function of the thickness of the aluminum substrate 2. From the graph, the rigidity δ is 0.005 kgf · m
It can be seen that the thickness of the aluminum substrate 2 having m to 0.15 kgf · mm is in the range of 22 μm to 66 μm.

From this, at least the diameter of 50 to 13
In the 0 mm optical disc 1, when the aluminum substrate 2 is used as the flexible metal substrate 2, by setting the thickness in the range of 22 μm to 66 μm, stable focusing becomes possible, and the ROM type optical disc 1 has It can be said that the uneven pit information can be reproduced.

Further, the focus error amount is ± 0.
In order to make it 1 μm or less, the rigidity of the metal substrate 2 is 0.008.
Since it is a range satisfying kgf · mm to 0.122 kgf · mm, when the aluminum substrate 2 is used as the flexible metal substrate 2 as seen from the graph of FIG. 19, its thickness is in the range of 25 μm to 61 μm. Is more preferable.

Example 4 Instead of the stainless substrate 2 described in Example 1, a metal substrate 2 made of iron (hereinafter, iron substrate 2) can be used.

Therefore, here, the rigidity δ of the metal substrate 2 obtained in Example 1 is 0.005 kgf · mm to 0.15.
The thickness of the iron substrate 2 which was kgf · mm was determined.

Young's modulus of iron E = 21600 kgf / mm
^2. Substituting iron Poisson's ratio v = 0.30 into equation (1),
The stiffness δ of the iron substrate 2 as a function of the thickness of the iron substrate 2 is shown in FIG.
A graph of 0 was obtained. From the graph, the rigidity δ is 0.005
It can be seen that the iron substrate 2 having a thickness of kgf · mm to 0.15 kgf · mm has a thickness in the range of 15 μm to 45 μm.

Therefore, at least the diameter of 50 to 13
In the 0 mm optical disc 1, when the iron substrate 2 is used as the flexible metal substrate 2, its thickness is 15 μm.
It can be said that by setting the thickness in the range of m to 45 μm, stable focusing becomes possible and the concave and convex pit information of the ROM type optical disc 1 can be reproduced.

Further, the focus error amount is ± 0.
In order to make it 1 μm or less, the rigidity of the metal substrate 2 is 0.008.
Since the range satisfies kgf · mm to 0.122 kgf · mm, when the iron substrate 2 is used as the flexible metal substrate 2 as shown in the graph of FIG.
More preferably, it is in the range of 7 μm to 42 μm.

[Embodiment 5] Instead of the stainless steel substrate 2 described in Embodiment 1, a metal substrate 2 made of copper (hereinafter, copper substrate 2) can be used.

Therefore, here, the rigidity δ of the metal substrate 2 obtained in Example 1 is 0.005 kgf · mm to 0.15.
The thickness of the copper substrate 2 to be kgf · mm was determined.

Young's modulus of copper E = 13000 kgf / mm
² , the Poisson's ratio of copper v = 0.343 was substituted into the equation (1), and the rigidity δ of the copper substrate 2 was obtained as a function of the thickness of the copper substrate 2 to obtain the graph of FIG. From the graph, the rigidity δ is 0.0
It can be seen that the thickness of the copper substrate 2 that is 05 kgf · mm to 0.15 kgf · mm is in the range of 18 μm to 53 μm.

Therefore, at least the diameter of 50 to 13
In a 0 mm optical disc 1, when the copper substrate 2 is used as the flexible metal substrate 2, its thickness is 18 μm.
It can be said that by setting the thickness in the range of m to 53 μm, stable focusing becomes possible and the concave and convex pit information of the ROM type optical disc 1 can be reproduced.

Further, the focus error amount is ± 0.
In order to make it 1 μm or less, the rigidity of the metal substrate 2 is 0.008.
Since the range satisfies kgf · mm to 0.122 kgf · mm, when the copper substrate 2 is used as the flexible metal substrate 2 as shown in the graph of FIG.
The range of 1 μm to 50 μm is more preferable.

Example 6 Instead of the stainless substrate 2 described in Example 1, a metal substrate 2 made of nickel is used.
(Hereinafter, nickel substrate 2) can be used.

Therefore, here, the rigidity δ of the metal substrate 2 obtained in Example 1 is 0.005 kgf · mm to 0.15.
The thickness of the nickel substrate 2 having a value of kgf · mm was determined.

Young's modulus of nickel E = 21900 kgf
/ Mm ² , and Poisson's ratio of nickel v = 0.306 was substituted into the equation (1), and the rigidity δ of the nickel substrate 2 was obtained as a function of the thickness of the nickel substrate 2 to obtain the graph of FIG. From the graph, the rigidity δ is 0.005 kgf · mm to 0.15
The thickness of the nickel substrate 2, which is kgf · mm, is 15 μm.
It can be seen that the range is up to 44 μm.

Therefore, at least the diameter of 50 to 13
In the 0 mm optical disc 1, when the nickel substrate 2 is used as the flexible metal substrate 2, by setting the thickness in the range of 15 μm to 44 μm, stable focusing becomes possible, and the ROM type optical disc 1 is It can be said that the uneven pit information can be reproduced.

Further, the focus error amount is ± 0.
In order to make it 1 μm or less, the rigidity of the metal substrate 2 is 0.008.
Since it is a range satisfying kgf · mm to 0.122 kgf · mm, when the nickel substrate 2 is used as the flexible metal substrate 2 as shown in the graph of FIG. 22, the thickness is in the range of 17 μm to 41 μm. Is more preferable.

[Embodiment 7] Instead of the stainless steel substrate 2 described in Embodiment 1, a metal substrate 2 made of titanium is used.
(Hereinafter, titanium substrate 2) can be used.

Therefore, here, the rigidity δ of the metal substrate 2 obtained in Example 1 is 0.005 kgf · mm to 0.15.
The thickness of the titanium substrate 2 to be kgf · mm was determined.

Young's modulus of titanium E = 11600 kgf /
mm ² and the Poisson's ratio of titanium v = 0.321 are given by the formula (1).
And the stiffness δ of the titanium substrate 2 as a function of the thickness of the titanium substrate 2 was obtained. From the graph,
Rigidity δ is 0.005 kgf · mm to 0.15 kgf · m
It can be seen that the titanium substrate 2 having a thickness of m is in the range of 18 μm to 55 μm.

From this, at least the diameter of 50 to 13
In a 0 mm optical disc 1, when a titanium substrate 2 is used as the flexible metal substrate 2, its thickness is 1
By setting the thickness in the range of 8 μm to 55 μm, stable focusing becomes possible, and it can be said that the uneven pit information of the ROM type optical disc 1 can be reproduced.

Further, the focus error amount is ± 0.
In order to make it 1 μm or less, the rigidity of the metal substrate 2 is 0.008.
Since it is a range satisfying kgf · mm to 0.122 kgf · mm, as seen from the graph of FIG. 23, when the titanium substrate 2 is used as the flexible metal substrate 2, the thickness thereof is in the range of 21 μm to 52 μm. Is more preferable.

Example 8 The screen described in Example 1 was used.
Instead of the tenless substrate 2, the composition ratio Ti₉₀Al₆V _FourJi
Metal substrate 2 made of a tongue alloy (hereinafter, titanium alloy substrate
2) can be used.

Therefore, here, the rigidity δ of the metal substrate 2 obtained in Example 1 is 0.005 kgf · mm to 0.15.
The thickness of the titanium alloy substrate 2 of kgf · mm was determined.

Young's modulus of titanium alloy E = 15000 kg
By substituting f / mm ² and the Poisson's ratio v = 0.33 of the titanium alloy into the equation (1), the rigidity δ of the titanium alloy substrate 2 was obtained as a function of the thickness of the titanium alloy substrate 2 to obtain the graph of FIG.
From the graph, the rigidity δ is 0.005 kgf · mm to 0.
The thickness of the titanium alloy substrate 2 that becomes 15 kgf · mm is 1
It can be seen that the range is from 7 μm to 51 μm.

From this, at least the diameter of 50 to 13
In the 0 mm optical disc 1, when the titanium alloy substrate 2 is used as the flexible metal substrate 2, by setting the thickness in the range of 17 μm to 51 μm, stable focusing becomes possible, and the ROM type optical disc 1 It can be said that the uneven pit information of can be reproduced.

Further, the focus error amount is ± 0.
In order to make it 1 μm or less, the rigidity of the metal substrate 2 is 0.008.
Since it is in the range of satisfying kgf · mm to 0.122 kgf · mm, when the titanium alloy substrate 2 is used as the flexible metal substrate 2 as shown in the graph of FIG. 24, its thickness is 20 μm to 47 μm. The range is more preferable.

Example 9 Instead of the stainless steel substrate 2 described in Example 1, the composition ratio Al _95.5 Cu ₄ Mg was used.
It is possible to use a metal substrate 2 (hereinafter, duralumin substrate 2) made of duralumin, which is one of _0.5 aluminum alloys.

Therefore, here, the rigidity δ of the metal substrate 2 obtained in Example 1 is 0.005 kgf · mm to 0.15.
The thickness of the duralumin substrate 2 of kgf · mm was determined.

Duralumin's Young's modulus E = 7150 kg
f / mm ² , Poisson's ratio of duralumin v = 0.335
Is substituted into the equation (1), and the rigidity δ of the duralumin substrate 2 is
The graph of FIG. 25 was obtained as a function of the thickness of the duralumin substrate 2. From the graph, the rigidity δ is 0.005 kgf · m
It can be seen that the thickness of the duralumin substrate 2 with m to 0.15 kgf · mm is in the range of 22 μm to 65 μm.

Therefore, at least the diameter of 50 to 13
In the 0 mm optical disc 1, when the duralumin substrate 2 is used as the flexible metal substrate 2, by setting the thickness in the range of 22 μm to 65 μm, stable focusing becomes possible, and the ROM type optical disc 1 has It can be said that the uneven pit information can be reproduced.

Further, the focus error amount is ± 0.
In order to make it 1 μm or less, the rigidity of the metal substrate 2 is 0.008.
Since the range satisfies kgf · mm to 0.122 kgf · mm, when the duralumin substrate 2 is used as the flexible metal substrate 2 as shown in the graph of FIG. 25, the thickness thereof is in the range of 25 μm to 60 μm. Is more preferable.

Example 10 Instead of the stainless steel substrate 2 described in Example 1, the composition ratio Cu _91.8 Sn ₈ P
It is possible to use the metal substrate 2 (hereinafter, phosphor bronze substrate 2) made of phosphor bronze, which is a type of _0.2 copper alloy.

Therefore, here, the rigidity δ of the metal substrate 2 obtained in Example 1 is 0.005 kgf · mm to 0.15.
The thickness of the phosphor bronze substrate 2 having a value of kgf · mm was determined.

Young's modulus of phosphor bronze E = 12000 kgf
/ Mm ² and the Poisson's ratio v = 0.38 of phosphor bronze were substituted into the equation (1), and the rigidity δ of the phosphor bronze substrate 2 as a function of the thickness of the phosphor bronze substrate 2 was obtained. From the graph, the rigidity δ is 0.005 kgf · mm to 0.15
The thickness of the phosphor bronze substrate 2, which is kgf · mm, is 18 μm.
It can be seen that the range is up to 55 μm.

From this, at least the diameter of 50 to 13
In the 0 mm optical disc 1, when the phosphor bronze substrate 2 is used as the flexible metal substrate 2, by setting the thickness within the range of 18 μm to 55 μm, stable focusing becomes possible, and the ROM type optical disc 1 It can be said that the uneven pit information of can be reproduced.

The focus error amount is ± 0.
In order to make it 1 μm or less, the rigidity of the metal substrate 2 is 0.008.
Since the range is in the range of kgf · mm to 0.122 kgf · mm, when the phosphor bronze substrate 2 is used as the flexible metal substrate 2 as shown in the graph of FIG. 26, the thickness is 22 μm to 52 μm. The range is more preferable.

[Embodiment 11] In Embodiments 1 to 10, the read-only optical disc 1 capable of reproducing the concave-convex pit information of the ROM-type optical disc 1 is described, but the metal substrate 2 obtained here is used. Required stiffness,
In addition, the thickness of the metal substrate 2 for each material specified by the rigidity is not limited to the ROM type optical disc 1 and is applicable to the flexible metal substrate 2 of the rewritable optical disc 1.

That is, also in the rewritable optical disc 1, the thickness of the recording medium layer 4 is about several tens of nm, which is significantly smaller than the thickness of the metal substrate 2, and has almost no influence on the rigidity of the optical disc 1. It is considered to be a thing. The Young's modulus of the resin layer 3 formed by the 2P method and the light-transmitting protective layer 5 made of an ultraviolet curable resin are also 230 k.
The value is gf · mm ² , which is two orders of magnitude smaller than the Young's modulus of the metal substrate 2, and the influence on the rigidity of the optical disc 1 is extremely small and can be ignored. Therefore, even in the rewritable optical disc 1, the rigidity of the metal substrate 2 can be treated as the rigidity of the optical disk 1, ignoring the existence of the recording medium layer 4, the resin layer 3, and the light-transmitting protective layer 5.
The rigidity of the metal substrate 2 that can perform good focusing is
This is the same as the metal substrate 2 of the ROM type optical disc 1 obtained in the first embodiment.

Here, the metal substrate 2 has a thickness of 20 μm.
m, stainless steel with a diameter of 50 mm (Fe ₇₆ Cr ₁₇ Ni ₇ )
Using a substrate, on the stainless steel substrate 2 by the 2P method,
A resin layer 3 having a layer thickness of 5 μm and having an uneven guide groove pattern having a depth of 30 nm and a pitch of 0.3 μm was formed. Next, as the recording medium layer 4, an Al reflection film 11 having a film thickness of 100 nm, a ZnS-SiO2 interference layer 12 having a film thickness of 10 nm, and a film thickness of 4 nm.
SiN protective layer 13, 20 nm thick GeSbTe phase change recording layer 14, 4 nm thick SiN protective layer 15, 4 nm thick
A ZnS—SiO 2 interference layer 16 having a thickness of 0 nm was sequentially formed by sputtering to form a phase change recording medium layer (FIG. 7).
reference). Next, as the light-transmitting protective layer 5, an ultraviolet curable resin layer having a layer thickness of 5 μm is formed by the 2P method, and a rewritable phase change recording material is used for the optical disc 1 having a diameter of 50 mm.
Was produced.

After the center hub was adhered and fixed to the rewritable optical disk 1, the optical disk device shown in FIG. 9 was mounted and the recording / reproducing characteristics were examined. Here, a semiconductor laser having a wavelength of 405 nm was used as the light emitting element of the optical disk recording device, and a two-group objective lens having a numerical aperture NA of 0.85 was used as the condensing means 28.

With the number of rotations of the optical disc 1 set to 2000 rpm, the guide groove 9 is placed at the position of the radius 18 mm of the optical disc 1.
(See FIG. 5) Tracking is performed, and a recording mark having a mark length of 0.12 μm and a mark pitch of 0.24 μm is recorded by irradiating an optical pulse with a recording power of 5 mW, and then with a reproducing power of 0.5 mW. The above recorded information was reproduced by irradiating continuous light. As a result of evaluating the output from the light-receiving element for reproducing signal detection with a spectrum analyzer, it was confirmed that a signal-to-noise ratio of 48 dB was obtained, and it is practically applicable to the flexible optical disc 1 and its optical disc device of the present invention. It was confirmed that recording and playback could be realized.

Also, as the flexible metal substrate 2,
Diameter 50 using the same rewritable phase change recording material using the metal substrate 2 described in Example 3 to Example 10
As a result of producing an optical disc 1 having a size of 1 mm and recording / reproducing information, it was confirmed that practical recording / reproducing could be realized with any of them.

[Embodiment 12] Here, an embodiment will be shown in which a magneto-optical recording medium capable of magnetic super-resolution reproduction is used as the recording medium of the rewritable optical disc 1.

Here, the metal substrate 2 has a thickness of 20 μm.
m, stainless steel with a diameter of 50 mm (Fe ₇₆ Cr ₁₇ Ni ₇ )
Using a substrate, on the stainless steel substrate 2 by the 2P method,
A resin layer 3 having a layer thickness of 5 μm and having an uneven guide groove pattern having a depth of 30 nm and a pitch of 0.3 μm was formed. Next, as the recording medium layer 4, an AgTi heat dissipation layer 17 having a film thickness of 20 nm,
AlN protective layer 18 with a film thickness of 10 nm, Tb with a film thickness of 40 nm
FeCo recording layer 19, Al non-magnetic intermediate layer 2 having a film thickness of 5 nm
0, GdFeCo reproducing layer 21 having a film thickness of 25 nm, film thickness 40
nm AlN interference layer 22 was sequentially formed by sputtering to form a magneto-optical recording medium layer capable of magnetic super-resolution reproduction (see FIG. 8). Next, as the light-transmitting protective layer 5,
An ultraviolet curable resin layer having a layer thickness of 5 μm is formed by the 2P method,
An optical disc 1 having a diameter of 50 mm was manufactured using a magneto-optical recording medium capable of rewriting and magnetic super-resolution reproduction.

The optical disk 1 having the above flexibility is shown in FIG.
The recording / reproducing characteristics were examined using the optical disk device shown in FIG. Here, a semiconductor laser having a wavelength of 405 nm was used as the light emitting element of the optical disk device, and a two-group objective lens having a numerical aperture of 0.85 was used as the condensing means 28.

The rotation speed of the optical disk 1 is 2000 rp
As m, tracking is performed with respect to the guide groove 9 (see FIG. 5) at a radius of 20 mm of the optical disc 1, and a magnetic field of ± 16 kA / m is applied by the magnetic head 33, and 5 m
Continuous light is radiated with a recording power of W to align the magnetization direction of the recording layer 19 with the direction corresponding to the modulation magnetic field, and the mark length of 0.
After forming recording marks of 08 μm and a mark pitch of 0.16 μm, continuous light was irradiated with a reproducing power of 1.5 mW,
The recorded information was reproduced. As a result of evaluating the output from the light receiving element for reproducing signal detection with a spectrum analyzer,
It was confirmed that a signal-to-noise ratio of 46 dB was obtained, and it was confirmed that practicable recording / reproducing could be realized in the flexible optical disc 1 and the optical disc device thereof of the present invention.

Also, as the flexible metal substrate 2,
A diameter of 50 using the same rewritable magneto-optical recording material as the metal substrate 2 described in the third to tenth embodiments.
As a result of producing an optical disc 1 having a size of 1 mm and recording / reproducing information, it was confirmed that practical recording / reproducing could be realized with any of them.

[Embodiment 13] Here, FIGS.
An example of the optical disc cartridge 50 in which the optical disc 1 using the phase change recording medium for the recording medium layer 4 shown in FIG.

The cartridge case 37 is made of polycarbonate having a thickness of 0.6 mm formed by injection molding,
The distance between the upper inner wall surface 38 and the lower inner wall surface 39 is 1 mm.
Is. In the cartridge case 37, the eleventh embodiment
The optical disk 1 using the phase change recording medium described in 1 above was inserted into the recording medium layer 4, and the same recording / reproducing experiment as in Example 11 was conducted using the optical disk device of FIG.

As a result, it was confirmed that the same recording / reproducing characteristics as those of Example 11 were obtained and that the inner wall surface 39 of the cartridge case 37 of this example worked as a stabilizing plate.

Also, when the cartridge case 37 is made of stainless steel having a wall thickness of 0.2 mm, the same result as above is obtained.

[Embodiment 14] Here, an embodiment of the optical disk cartridge 50 'shown in FIG. 15 in which the optical disk 1 using the magneto-optical recording medium for the recording medium layer 4 is housed in the cartridge case 37' will be described.

The cartridge case 37 'is made of injection-molded polycarbonate having a thickness of 0.6 mm, and the distance between the upper inner wall surface 38 and the lower inner wall surface 39 is 1.
mm. A recording / reproducing experiment similar to that in Example 12 was performed by inserting the optical disc 1 using the magneto-optical recording medium in the recording medium layer 4 described in Example 12 into the cartridge case 37 and using the optical disc apparatus in FIG. I went.

As a result, it was confirmed that the same recording / reproducing characteristics as those in Example 12 were obtained and that the inner wall surface 39 of the cartridge case 37 'of this example worked as a stabilizing plate.

Also, when the cartridge case 37 'is made of duralumin having a thickness of 0.2 mm, the same result as the above is obtained.

[Embodiment 15] Here, an embodiment of the optical disk cartridge 50a shown in FIG. 16 in which the optical disk 1 using the phase change recording medium for the recording medium layer 4 is housed in the cartridge case 37a and is strong against external disturbance such as impact is shown. About.

Optical disk 1 and cartridge case 37a
The distance between both inner wall surfaces 38 and 39 is t1, the thickness of the optical disc 1 is t2, and (t1−t2) is 20 μm to 40 μm.
Cartridge cases 37a of various sizes satisfying the range of 0 μm were prepared, and the optical disk 1 using the phase change recording medium in the recording medium layer 4 described in Example 11 was inserted therein and the same as in Example 11. As a result of various recording / reproducing experiments, it was confirmed that the same recording / reproducing characteristics as those in Example 11 were obtained, and that each cartridge case 37a produced here worked as a stabilizing plate.

[Embodiment 16] Here, an embodiment of the optical disk cartridge 50a shown in FIG. 17 in which the optical disk 1 using the magneto-optical recording medium in the recording medium layer 4 is housed in the cartridge case 37a and is strong against external disturbance such as impact. About.

Optical disk 1 and cartridge case 37a
The distance between both inner wall surfaces 38 and 39 is t1, the thickness of the optical disc 1 is t2, and (t1−t2) is 20 μm to 40 μm.
Cartridge cases 37a of various sizes satisfying the range of 0 μm were created, and the optical disc 1 using the magneto-optical recording medium was inserted into the recording medium layer 4 described in Example 11 therein, and the same as in Example 11. As a result of conducting a recording / reproducing experiment, it was confirmed that the same recording / reproducing characteristics as those in Example 12 were obtained, and that each cartridge case 37a produced here worked as a stabilizing plate.

[0197]

The flexible optical disk of the present invention is
As described above, the resin layer having the concavo-convex pit pattern, the metal reflection layer, and the light-transmitting protective layer are sequentially formed on the flexible metal substrate.

As described above, the flexible optical disk of the present invention has a resin layer, an optical recording layer, and a resin layer having an uneven pit pattern and / or an uneven guide groove pattern on a flexible metal substrate. It is characterized in that a light-transmitting protective layer is sequentially formed.

As a result, the rigidity itself required for a flexible optical disk can be obtained from the metal substrate, so that light transmission for recording or reproduction on the side opposite to the metal substrate is performed. By reducing the thickness of the property protection layer, the wavelength of light is shortened, the numerical aperture NA of the objective lens is increased, and even when the light beam spot is reduced, the allowable amount for the tilt of the optical disc is expanded. can do. The thickness of the transparent protective film on the light incident side can be made as thin as possible without being restricted by the rigidity and the like required for a flexible optical disk.

Further, since the metal itself has a very high rigidity as compared with the resin, it can be made extremely thin even if it has a rigidity required for a flexible optical disk.
Not to mention making the optical disc itself thinner,
The optical disk device can be thinned.

In the flexible optical disk of the present invention, the resin layer may be formed of an ultraviolet curable resin, and in this case, the resin layer preferably has a film thickness of 1 μm to 50 μm. The fine irregularities on the surface of the metal substrate can be covered with the resin layer, and it does not take a long time to cure the resin layer. A phase change recording medium or a magneto-optical recording medium can be used for the optical recording layer. Further, the light-transmitting protective layer can also be formed from an ultraviolet curable resin.

In the flexible optical disc of the present invention, the metal substrate has a rigidity of 0.005 kgf.
-Mm-0.150 kgf-mm can also be characterized. When the rigidity of the metal substrate satisfies the above range, it is possible to easily realize the flexible optical disk of the present invention having the above-described actions and effects.

As the metal substrate, one made of aluminum can be used, and the thickness of the metal substrate in that case is in the range of 22 μm to 66 μm. This has the effect that a flexible optical disc can be easily realized.

Further, as the metal substrate, one made of iron can be used, and in this case, the thickness of the metal substrate is set in the range of 15 μm to 45 μm, whereby the above-described action and effect of the present invention can be obtained. This has the effect that a flexible optical disc can be easily realized.

Further, as the metal substrate, one made of copper can be used. In this case, the thickness of the metal substrate is in the range of 18 μm to 53 μm. This has the effect that a flexible optical disc can be easily realized.

As the metal substrate, one made of nickel may be used. In this case, the thickness of the metal substrate is set in the range of 15 μm to 44 μm. This has the effect that a flexible optical disc can be easily realized.

As the metal substrate, one made of titanium may be used. In this case, the thickness of the metal substrate is set in the range of 18 μm to 55 μm. This has the effect that a flexible optical disc can be easily realized.

Further, as the metal substrate, a substrate made of an iron alloy containing iron as a main component can be used, and one example thereof is stainless steel made of Fe, Cr and Ni. The thickness of the substrate is 14
By setting the thickness in the range of μm to 43 μm, it is possible to easily realize the flexible optical disk of the present invention having the above-described actions and effects.

Further, as the metal substrate, one made of a titanium alloy containing titanium as a main component can be used, and a titanium alloy made of Ti, Al and V can be mentioned as one of the examples. By setting the thickness of the metal substrate to be in the range of 17 μm to 51 μm, it is possible to easily realize the flexible optical disk of the present invention having the above-described actions and effects.

Further, as the metal substrate, one made of an aluminum alloy containing aluminum as a main component can be used, and one example thereof is duralumin made of Al, Cu, and Mg. In that case, the metal substrate is used. By setting the thickness to be in the range of 22 μm to 65 μm, it is possible to easily realize the flexible optical disk of the present invention having the above-described action and effect.

Further, as the metal substrate, a substrate made of a copper alloy containing copper as a main component can be used, and phosphor bronze made of Cu, Sn, and P can be mentioned as one type thereof. The thickness of the metal substrate is 18 μm
By setting the thickness in the range of up to 55 μm, it is possible to easily realize the flexible optical disk of the present invention that achieves the above-described actions and effects.

The flexible optical disc cartridge of the present invention is obtained by inserting the flexible optical disc of the present invention into an optical disc cartridge case. In the case of a flexible optical disc, a stabilizing plate is required at a position facing the optical disc for stable rotation. According to this, the inner wall surface of the optical disc cartridge case facing the optical disc is a stabilizing plate. Since there is no need to provide a stabilizing plate on the optical disc device side, the configuration of the optical disc device can be simplified compared to the case where the stabilizing plate is provided.

Further, in the optical disk cartridge of the present invention, the distance between both inner wall surfaces facing the optical disk in the optical disk cartridge case is set so that the optical disk stably rotates at an intermediate position between both inner wall surfaces. Is more preferable.

By thus setting the distance between both inner wall surfaces of the optical disk cartridge case so that the optical disk stably rotates at an intermediate position between both inner wall surfaces, the optical disk stabilizes both inner wall surfaces 38 and 39. Since it is used as a plate to rotate, it is possible to provide a structure that is more resistant to disturbance.

In this case, the distance between both inner wall surfaces of the optical disk cartridge case is t1, and the thickness of the optical disk is t2.
In this case, by designing t1-t2 to be 20 μm to 400 μm, it is possible to easily obtain the above-mentioned optical disc cartridge that is resistant to disturbance.

Further, as the optical disk cartridge,
Since the optical disc cartridge case is made of metal, the thickness of the cartridge case itself can be made thin, so that the optical disc cartridge can be made thinner and the optical disc device can be made thinner.

Further, the optical disk device of the present invention is an optical disk device for recording or reproducing on or from the above-mentioned flexible optical disk of the present invention or the optical disk cartridge of the present invention. It is characterized in that the metal layer or the optical recording layer is irradiated with light from the protective layer side.

With such a structure, the above-mentioned optical disc and optical disc cartridge of the present invention are
It is possible to provide an apparatus capable of recording or reproducing information.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional perspective view showing a configuration of an optical disc according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of the optical disc.

FIG. 3 is a drawing showing a state of a step in a method of manufacturing the optical disc.

FIG. 4 is a cross-sectional view of an optical disc in the process of manufacturing the optical disc.

FIG. 5 is a partial cross-sectional perspective view showing a surface state of a resin layer of the optical disc.

FIG. 6 is a partial cross-sectional perspective view showing another surface state of the resin layer of the optical disc.

FIG. 7 is a partial cross-sectional view showing in detail the structure of a recording medium layer of the optical disc.

FIG. 8 is a partial cross-sectional view showing another configuration of the recording medium layer of the optical disc in detail.

FIG. 9 is a drawing schematically showing a configuration of an optical disc device according to an embodiment of the present invention.

FIG. 10 is a drawing schematically showing a configuration of an optical disc device according to another embodiment of the present invention.

11 is a plan view of a stabilizing plate mounted on the optical disc device of FIG.

FIG. 12 is a cross-sectional view showing a state in which the optical disk cartridge according to the embodiment of the present invention is rotationally driven.

FIG. 13 is a plan view of the optical disc cartridge.

FIG. 14 is a drawing schematically showing a configuration of an optical disk device having another optical disk cartridge according to another embodiment of the present invention.

FIG. 15 is a drawing schematically showing a configuration of an optical disk device of another embodiment of the present invention including an optical disk cartridge of another embodiment of the present invention.

FIG. 16 is a drawing schematically showing a configuration of an optical disc device according to still another embodiment of the present invention, which is provided with an optical disc cartridge according to still another embodiment of the present invention.

FIG. 17 is a drawing schematically showing a configuration of an optical disk device of still another embodiment of the present invention including an optical disk cartridge of yet another embodiment of the present invention.

FIG. 18 is a graph showing the relationship between the substrate thickness and the rigidity of a slenless substrate in an optical disc.

FIG. 19 is a graph showing the relationship between the substrate thickness and the rigidity of a substrate made of aluminum in an optical disc.

FIG. 20 is a graph showing the relationship between the substrate thickness and the rigidity of a substrate made of iron in an optical disc.

FIG. 21 is a graph showing the relationship between substrate thickness and rigidity of a substrate made of copper in an optical disc.

FIG. 22 is a graph showing the relationship between the substrate thickness and the rigidity of a substrate made of nickel in an optical disc.

FIG. 23 is a graph showing the relationship between the substrate thickness and the rigidity of a substrate made of titanium in an optical disc.

FIG. 24 is a graph showing the relationship between the substrate thickness and the rigidity of a substrate made of a titanium alloy in an optical disc.

FIG. 25 is a graph showing the relationship between substrate thickness and rigidity of a substrate made of duralumin in an optical disc.

FIG. 26 is a graph showing the relationship between substrate thickness and rigidity of a substrate made of phosphor bronze in an optical disc.

FIG. 27 is a schematic view of a conventional optical disc device.

FIG. 28 is a cross-sectional view showing a state where the conventional optical disc cartridge is rotationally driven.

FIG. 29 is a graph showing the relationship between substrate thickness and rigidity of a resin substrate in a conventional optical disc.

[Explanation of symbols]

1 optical disc 2 metal substrate 3 resin layers 3'resin layer 4 Recording medium layer (optical recording layer) 4'metal reflective layer 5 Light-transmissive protective layer 6 Mirror plate 7 Transparent stamper 7'Transparent stamper 8 ultraviolet rays 9 Guide groove (concavo-convex guide groove pattern) 10 pits (uneven pit pattern) 23 Center Hub 24 spindles 25 Stabilizer 26 Light emitting and receiving element section 27 light beams 28 Condensing means 29 mirror 30 2-axis actuator 31 Signal processing circuit 32 optical pickup 33 magnetic head 34 second hole 35 First hole 36 suspension 37 Optical disk cartridge case 37 'optical disk cartridge case 37a Optical disk cartridge case 37'a optical disk cartridge case 38 Inner wall surface on the upper side 39 Inner wall surface on the lower side 40 First opening 41 Second opening 42 slide shutter 43 Third opening 50 Optical disk cartridge 50 'optical disk cartridge 50a optical disk cartridge 50'a optical disk cartridge

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G11B 11/105 521 G11B 11/105 521B 521C 521D 23/03 604 23/03 604P 604Z F term (reference) 5D029 JB18 KA22 KA23 KB06 KB14 KC09 LB13 MA34 PA09 5D075 FF20 FG04 FG14 FH06 5D090 AA02 CC01 CC04 CC14 DD02 FF11

Claims (35)

[Claims] 1. A flexible optical disk comprising a flexible metal substrate, a resin layer having a concave-convex pit pattern, a metal reflection layer, and a light-transmitting protective layer, which are sequentially formed on the flexible metal substrate. 2. A resin layer having an uneven pit pattern and / or an uneven guide groove pattern, an optical recording layer, and a light transmitting protective layer are sequentially formed on a flexible metal substrate. Flexible optical disc. 3. The flexible optical disc according to claim 1, wherein the resin layer is made of an ultraviolet curable resin. 4. The flexible optical disk according to claim 3, wherein the resin layer has a thickness of 1 μm to 50 μm. 5. The flexible optical disk according to claim 2, wherein the optical recording layer is a recording layer using a phase change recording medium. 6. The flexible optical disk according to claim 2, wherein the optical recording layer is a recording layer using a magneto-optical recording medium. 7. The flexible optical disk according to claim 1, wherein the light-transmitting protective layer is made of an ultraviolet curable resin. 8. The rigidity of the metal substrate is 0.005 kgf.
The flexible optical disc according to any one of claims 1 to 7, wherein the optical disc has a weight of 0.1 mm to 0.150 kgf.mm. 9. The flexible optical disk according to claim 1, wherein the metal substrate is made of aluminum. 10. The metal substrate has a thickness of 22 μm to 66 μm.
The flexible optical disk according to claim 9, wherein the optical disk is m. 11. The flexible optical disk according to claim 1, wherein the metal substrate is made of iron. 12. The metal substrate made of iron has a thickness of 15 μm.
The flexible optical disk according to claim 11, wherein the optical disk has a thickness of m to 45 μm. 13. The flexible optical disk according to claim 1, wherein the metal substrate is made of copper. 14. The metal substrate made of copper has a thickness of 18 μm.
The flexible optical disk according to claim 13, wherein the optical disk has a thickness of m to 53 μm. 15. The flexible optical disk according to claim 1, wherein the metal substrate is made of nickel. 16. The metal substrate made of nickel has a thickness of 15 μm to 44 μm.
An optical disc having flexibility according to 1. 17. The flexible optical disk according to claim 1, wherein the metal substrate is made of titanium. 18. The thickness of the metal substrate made of titanium is 1
The flexible optical disc according to claim 17, wherein the optical disc has a thickness of 8 μm to 55 μm. 19. The flexible optical disk according to claim 1, wherein the metal substrate is made of an iron alloy containing iron as a main component. 20. The flexible optical disk according to claim 19, wherein the iron alloy is stainless steel composed of Fe, Cr, and Ni. 21. The metal substrate made of stainless steel has a thickness of 14 μm to 43 μm.
A flexible optical disc according to item 0. 22. The flexible optical disk according to claim 1, wherein the metal substrate is made of a titanium alloy containing titanium as a main component. 23. The flexible optical disk according to claim 22, wherein the titanium alloy is composed of Ti, Al, and V. 24. The flexible optical disk according to claim 23, wherein the metal substrate made of a titanium alloy of Ti, Al and V has a thickness of 17 μm to 51 μm. 25. The flexible optical disk according to claim 1, wherein the metal substrate is made of an aluminum alloy containing aluminum as a main component. 26. The aluminum alloy comprises Al, Cu and M.
The flexible optical disk according to claim 25, which is a duralumin composed of g. 27. The flexible optical disk according to claim 26, wherein the metal substrate made of duralumin has a thickness of 22 μm to 65 μm. 28. The flexible optical disk according to claim 1, wherein the metal substrate is made of a copper alloy containing copper as a main component. 29. The flexible optical disk according to claim 28, wherein the copper alloy is phosphor bronze composed of Cu, Sn and P. 30. The thickness of the metal substrate made of phosphor bronze is 18 μm to 55 μm.
An optical disc having flexibility according to 1. 31. An optical disk cartridge, wherein the flexible optical disk according to any one of claims 1 to 30 is inserted into an optical disk cartridge case. 32. The distance between both inner wall surfaces facing the inserted flexible optical disk in the optical disk cartridge case is set so that the optical disk stably rotates at an intermediate position between both inner wall surfaces. The optical disk cartridge according to claim 31, wherein the optical disk cartridge is a cartridge. 33. When the distance between both inner wall surfaces of the optical disk cartridge case is t1 and the thickness of the flexible optical disk is t2, t1-t2 is 20 μm to 400.
The optical disk cartridge according to claim 32, wherein the optical disk cartridge has a thickness of μm. 34. The optical disk cartridge case,
The optical disk cartridge according to any one of claims 31 to 33, which is made of metal. 35. An optical disc device for recording or reproducing on or from the flexible optical disc according to any one of claims 1 to 30 or the optical disc cartridge according to any one of claims 31 to 34. An optical disk device characterized in that the metal reflective layer or the optical recording layer is irradiated with light from the light-transmitting protective layer side of the flexible optical disk.