JP2000003524A - Recording/reproducing device for information recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording/reproducing method and device capable of suppressing a focus error signal due to a warp of an information recording medium and obtaining a stable recording signal amplitude. SOLUTION: This recording/reproducing device is provided with a rotary motor 11 placing the information recording medium 9 sticking a first resin substrate 1 provided with an overcoat layer on a thin film containing a recording layer with a second resin substrate 7 provided with the overcoat layer through an adhesive resin and driving it to rotate at a prescribed number of revolution, an optical head 12 provided with a light source generating a light beam recording an information signal on the recording layer of the information record medium 9, and reproducing or erasing the recorded information and an actuator 13 controlling the position of the optical head 12 for the recording layer according to the focus error signal from a focus control means 14. Thus, an FE(focus error) signal and an RF signal are stabilized, and even an ordinary recording/reproducing device records, reproduces and/or erases the information with a margin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art A write-once information recording medium or a rewritable information recording medium has been commercialized as a large-capacity, high-density memory for data files or image files.

[0003] These information recording media are manufactured in a single plate or a laminated structure, and have a small size of 86 mm in diameter for data files and a diameter of 3 mm for image files.
There are several types up to a large medium of 0 cm. When manufacturing the information recording medium of the bonding structure, after a thin film is formed on the substrate,
An overcoat of an organic material is applied on the thin film by spin coating or the like to protect the thin film. There are two types of information recording media, one having a single-sided recording surface and the other having a double-sided recording surface. In the case of a medium having a recording surface on both surfaces, a thin film is formed and an adhesive film is applied to two overcoated substrates. Apply resin and stick each other. On the other hand, in the case of a medium having a single-sided recording surface, it is manufactured by a process of bonding a substrate on which a thin film and an overcoat layer are formed and a substrate on which the thin film and the overcoat layer are not formed.

A recording / reproducing method or a recording / reproducing apparatus for recording, reproducing or erasing using any of the above information recording media has been proposed.

[0005]

However, in the case of a conventional recording medium, particularly a recording medium having a single-sided recording surface, a thin film including a recording layer is required for bonding an overcoated substrate and an uncoated substrate. The recording medium is warped due to the internal stress of the medium. In particular, the larger the diameter of the medium, the greater the warpage. There has been a problem that the focus error signal, which is a follow-up signal, partially increases, and amplitude unevenness occurs in the reproduced signal.

An object of the present invention is to provide a recording and reproducing method and apparatus capable of suppressing a focus error signal caused by warpage of an information recording medium and obtaining a stable recording signal amplitude. And

[0007]

In order to achieve the above object, a recording / reproducing method according to the present invention comprises: a first resin substrate having an organic material overcoat layer laminated on a thin film including a recording layer; Driving means for rotating and driving an information recording medium in which the overcoat layer is bonded to the second resin substrate having the overcoat layer formed thereon through an adhesive resin;
An optical head for emitting a light beam for recording or reproducing an information signal on or from a recording layer, and an optical head adjusting means for generating a focus following signal for the recording layer of the optical head and controlling the focus of the light beam. It is.

Further, the recording / reproducing apparatus of the present invention comprises a first resin substrate having an organic material overcoat layer laminated on a thin film including a recording layer, and a second resin substrate having an organic material overcoat layer formed thereon. And a rotation motor for rotating an information recording medium having an overcoat layer bonded to each other via an adhesive resin, an optical head for emitting a light beam for recording or reproducing an information signal on the recording layer, and a recording layer for the optical head. A focus control circuit for generating a focus following signal and controlling the focus of the light beam is provided.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an example of an information recording medium applied to a recording / reproducing method or a recording / reproducing apparatus of the present invention will be described. As shown in FIG. 2, a dielectric layer 2 is formed on a transparent first resin substrate 1 having a diameter of 30 cm by an RF sputtering method, and a recording layer 3, a reflective layer 4, and a protective layer 5 are formed in this order.
The layers are laminated by the C sputtering method. Then, the protective layer 5
Is provided with an overcoat layer 6 of an organic material by spin coating. Next, a second resin substrate 7 having a diameter of 30 cm
Is provided with an overcoat layer 6. Note that the second resin substrate in FIG. 2 is an example of a so-called dummy substrate on which thin films such as a dielectric layer, a recording layer, a reflective layer, and a protective layer are not formed.

After the overcoat layer 6 provided on each of the first resin substrate 1 and the second resin substrate 7 is completely cured, the adhesive resin 8 is applied onto the overcoat layer 6 of the first resin substrate 1 and // overcoat layer 6 of second resin substrate 7
And apply on top.

Since a curing step of curing the overcoat layers 6 of both substrates is performed before bonding as described above, the dielectric layer 2, the recording layer 3, the reflective layer 4, and the protective layer 5 before the bonding are performed.
The amount of deformation of the first resin substrate 1 caused by the internal stress of the overcoat layer 6 and the amount of deformation of the second resin substrate 7 caused by the internal stress of the overcoat layer 6 can be adjusted and bonded. After the recording, the warpage of the information recording medium can be extremely reduced.

That is, it is possible to suppress the difference in internal stress between the first resin substrate and the second resin substrate, and to bond two substrates in which the difference in the amount of deformation caused by the internal stress on the bonding surface is corrected. Because of this, an information recording medium with extremely small warpage can be realized, and at the same time, since the overcoat layer in contact with both surfaces of the bonding surface is made of an organic material, each of the first resin substrate and the second resin substrate is bonded to the adhesive. Adhesive force can be made strong, and the two resin substrates can be bonded together with an adhesive force against a restoring force against deformation of the first resin substrate and the second resin substrate. In addition, in the above example, the example using the second resin substrate 7 on which the thin film is not formed has been described. However, the intention of the present invention is that the two substrates to be bonded are provided on both sides of the adhesive layer. Over in contact with Since a configuration including over coat layer, the dielectric layer is not limited to the second resin substrate does not form a thin film,
When a second resin substrate provided with an overcoat layer after forming a thin film such as a reflective layer, a recording layer or a layer similar to these three layers can be used, the symmetry of distortion of both substrates with respect to the adhesive layer can be improved, Although the warpage of the information recording medium after the alignment can be reduced, the reason why the description is made using the substrate on which the thin film is not formed is that the warpage is the largest. In addition, 30cm in diameter
The reason for using the substrate described above is that the warpage is the largest.

Table 1 shows the results of measuring the warpage of 12 information recording media having a diameter of 30 cm produced in such a process.

[0014]

[Table 1]

As shown in Table 1, even a recording medium having a diameter of 30 cm and using the first and second resin substrates can minimize the warpage. The average value in Table 1 is 1.16 mrad.

FIG. 3 is a sectional view of a conventional recording medium. The second resin substrate 7 is bonded to the first resin substrate 1 without being overcoated. Table 2 shows the measurement results of the warpage in this structure. The average value is 7.58 mrad. In some media, warpage exceeding 15 mrad has occurred, and it is clear that the conventional structure easily warps.

[0017]

[Table 2]

Next, an embodiment of the recording / reproducing method and the recording / reproducing apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a conceptual diagram of a main part for explaining an embodiment of a recording / reproducing apparatus according to the present invention. The information recording medium 9 is
First resin substrate 1 including a dielectric layer, a recording layer, a reflective layer, a protective layer, and an overcoat layer (all not shown).
And a second resin substrate 7 provided with an overcoat layer (not shown) through a first resin via an adhesive resin (not shown).
The information recording medium is bonded so that both the resin substrate and the second resin substrate are outside.

Reference numeral 10 denotes a rotary motor on which the above-mentioned information recording medium 9 is placed and driven to rotate at a predetermined rotational speed.
An optical head is provided with a light source for recording an information signal on a recording layer (not shown) of the information recording medium 9 and generating a light beam for reproducing or erasing the recorded information. The actuator controls the position of the optical head 11 with respect to the recording layer in accordance with a focus control signal or a tracking control signal from a tracking control unit (not shown).

FIG. 4A shows an example of a focus error (FE) signal and a recording (RF) signal measured using a bonding type information recording medium having overcoat layers on both surfaces of the adhesive resin shown in FIG. FIG. 4B shows an example of the FE signal and the RF signal measured using the bonding type information recording medium having no overcoat layer on the second resin substrate shown in FIG. FIG.
As is apparent from FIG. 3, the recording medium having the configuration shown in FIG. 3 has a large warpage angle, so that the FE signal partially increases.
A phenomenon in which the RF signal amplitude in that portion drops and becomes small tends to occur, whereas the recording medium having the configuration shown in FIG. 2 has a small warpage angle, so that the RF signal amplitude and the FE signal are stable.

When the information recording medium 9 has a large warpage as shown in FIG. 3, for example, the optical head 1
In some cases, the FE signal for controlling the focus of No. 1 partially increases, and the RF signal has amplitude unevenness. As a result, for example, a jitter value when forming a recording mark on an adjacent track may be 10% or more. In some cases, the system exceeds the limit in which the actuator 12 can be corrected systematically, which causes a problem that recording or reproduction cannot be performed by a normal recording / reproducing apparatus.

On the other hand, when the information recording medium 9 has a structure with a very small warpage as shown in FIG. 2, for example, both the FE signal and the RF signal for controlling the focus of the optical head 11 on the recording layer are stable. However, the jitter value can be suppressed to about 9% or less, and it is possible to cope with high-density recording / reproducing (that is, a recording medium structure with a narrow track interval).

The information recording medium applicable to the present invention is not limited to the configuration shown in FIG. 2. For example, a multi-layer configuration in which the first resin substrate has two or more recording layers, a reflective layer And no protective layer, only one recording layer, second
Even if the resin substrate has, for example, a structure including one or more thin films of the dielectric layer, the reflective layer, the recording layer or the protective layer or a thin film similar thereto, the overcoat layer is in contact with the adhesive surface. Of course, any information recording medium provided on both sides of the adhesive surface can be applied to the recording / reproducing method and apparatus of the present invention.

[0025]

As described above, according to the recording / reproducing method or apparatus of the present invention, the warpage of the information recording medium is extremely small, so that the FE signal and the RF signal are stable, and even in a normal recording / reproducing apparatus. The effect that recording, reproduction and / or erasing with a margin can be performed is obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a main part of an information recording medium recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a partial sectional view of an information recording medium applied to the information recording apparatus of the present invention.

FIG. 3 is a partial cross-sectional view of a conventional information recording medium.

4A and 4B are waveform diagrams of an RF signal of an information recording medium and an FE signal, and FIG. 4A is a waveform diagram of an RF signal of an information recording medium according to an embodiment of the present invention, and FIG. RF signal and FE waveform diagram of medium

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 First resin substrate 2 Dielectric layer 3 Recording layer 4 Reflective layer 5 Protective layer 6 Overcoat layer 7 Second resin substrate 8 Adhesive resin 9 Information recording medium 10 Thin film 11 Rotary motor 12 Optical head 13 Actuator 14 Focus control means

[Procedure amendment]

[Submission date] June 24, 1999 (1999.6.2
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction contents]

[Document Name] Statement

Patent application title: Information recording medium recording / reproducing apparatus

[Claims]

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to relates to a recording re NamaSo location information recording medium for recording and reproducing erasing information optically.

[0002]

2. Description of the Related Art As a large-capacity and high-density memory, a write-once information recording medium and a rewritable information recording medium are used today.
It is commercialized for data files or image files.

[0003] These information recording media are manufactured in a single plate or a laminated structure, and have a small size of 86 mm in diameter for data files and a diameter of 3 mm for image files.
There are several types up to a large medium of 0 cm. When manufacturing the information recording medium of the bonding structure, after a thin film is formed on the substrate,
An overcoat of an organic material is applied on the thin film by spin coating or the like to protect the thin film. There are two types of information recording media, one having a single-sided recording surface and the other having a double-sided recording surface. In the case of a medium having a recording surface on both sides, a thin film is formed on the two overcoated substrates. Apply resin and stick each other. On the other hand, in the case of a medium having a single-sided recording surface, it is manufactured by a process of bonding a substrate on which a thin film and an overcoat layer are formed and a substrate on which the thin film and the overcoat layer are not formed.

A recording / reproducing method or a recording / reproducing apparatus for recording, reproducing or erasing using any of the above information recording media has been proposed.

[0005]

However, in the case of a conventional recording medium, particularly a recording medium having a single-sided recording surface, a thin film including a recording layer is required for bonding an overcoated substrate and an uncoated substrate. The recording medium is warped due to the internal stress of the medium. In particular, the larger the diameter of the medium, the greater the warpage. There has been a problem that the focus error signal, which is a follow-up signal, partially increases, and amplitude unevenness occurs in the reproduced signal.

An object of the present invention is to provide a recording and reproducing method and apparatus capable of suppressing a focus error signal caused by warpage of an information recording medium and obtaining a stable recording signal amplitude. And

[0007]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
In addition, the recording and reproducing apparatus of the present invention , one of the thin film including the recording layer
Other thin film comprising an overcoat layer of organic material on the major surface
A first substrate having a first resin substrate on one main surface;
On the outermost surface of any of the principal surfaces of the resin substrate and the second resin substrate
A second substrate and a drive rotating the first substrate and the second information recording medium by bonding over <br/> bar coating layer each other directly of the substrate through an adhesive resin having an overcoat layer of an organic material A rotating motor, an optical head for emitting a light beam for recording or reproducing an information signal on or from a recording layer, and a focus control circuit for generating a focus following signal for the recording layer of the optical head and controlling the focus of the light beam. And

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an example of the information recording medium to be applied to a recording re NamaSo location of the present invention. As shown in FIG. 2, a dielectric layer 2 is formed on a transparent first resin substrate 1 having a diameter of 30 cm by an RF sputtering method, and a recording layer 3, a reflective layer 4, and a protective layer 5 are formed by a DC sputtering method in this order. Laminate. After that, an overcoat layer 6 of an organic material was provided on the protective layer 5 by spin coating .
Obtain a substrate . Next, a second substrate having an overcoat layer 6 provided on a second resin substrate 7 having a diameter of 30 cm is obtained . In addition,
The second board in FIG. 2, the dielectric layer on the second resin substrate, a recording layer, examples of the second substrate so called dummy substrate on which a thin film such as a reflective layer and a protective layer is not formed It is.

After the overcoat layer 6 provided on each of the first resin substrate 1 and the second resin substrate 7 is completely cured, the adhesive resin 8 is applied on the overcoat layer 6 of the first resin substrate 1 and And / or overcoat layer 6 of second resin substrate 7
And apply on top.

Before the bonding, a curing step of curing the overcoat layers 6 of both substrates is performed. Therefore, the dielectric layer 2, the recording layer 3, the reflective layer 4, and the protective layer 5 before the bonding are performed.
The amount of deformation of the first resin substrate 1 caused by the internal stress of the overcoat layer 6 and the amount of deformation of the second resin substrate 7 caused by the internal stress of the overcoat layer 6 can be adjusted and bonded. After the recording, the warpage of the information recording medium can be extremely reduced.

[0011] That is, it is possible to suppress the difference in the internal stress of the first base plate and second base plate, paste the two substrates to correct the difference in deformation amount due to the internal stress relates adhesion surface fit for, at the same time warp is possible to realize a very small information recording medium, since the overcoat layer in contact with both surfaces of the adhesive surface is an organic material, the first base plate and second base plate, respectively and the adhesive No adhesion firmly obtained, an adhesive force against the restoring force against deformation of the first base plate and second base plate can be bonded to both substrates, the aging of the laminated type information recording medium Accompanying peeling can also be suppressed .

In the above example, an example is shown in which the second resin substrate 7 on which no thin film is formed is used. However, the intention of the present invention is that each of the substrates to be bonded is in contact with both sides of the adhesive layer. The overcoat layer is provided, so that not only the second resin substrate on which no thin film is formed but also a thin film such as a dielectric layer, a reflective layer, a recording layer, or a layer similar to these three layers is formed. The use of the second resin substrate provided with the coat layer can improve the symmetry of the distortion of the two substrates with respect to the adhesive layer and can reduce the warpage of the information recording medium after bonding, but the substrate on which the thin film is not formed This is because the warp is the largest. In addition, diameter 30
The reason for the explanation using the cm substrate is that the warpage is the largest.

Table 1 shows the results of measuring the warpage of 12 information recording media having a diameter of 30 cm produced in such a process.

[0014]

[Table 1]

As shown in Table 1, even a recording medium having a diameter of 30 cm and using the first and second resin substrates can minimize the warpage. The average value in Table 1 is 1.16 mrad.

FIG. 3 is a sectional view of a conventional recording medium. The second resin substrate 7 is bonded to the first resin substrate 1 without being overcoated. Table 2 shows the measurement results of the warpage in this structure. The average value is 7.58 mrad. In some media, warpage exceeding 15 mrad has occurred, and it is clear that the conventional structure easily warps.

[0017]

[Table 2]

[0018] Next, an embodiment of recording re NamaSo location of the present invention will be described with reference to the drawings.

FIG. 1 is a conceptual diagram of a main part for explaining an embodiment of a recording / reproducing apparatus according to the present invention. The information recording medium 9 is
First resin substrate 1 including a dielectric layer, a recording layer, a reflective layer, a protective layer, and an overcoat layer (all not shown).
And a second resin substrate 7 provided with an overcoat layer (not shown) through a first resin via an adhesive resin (not shown).
The information recording medium is bonded so that both the resin substrate and the second resin substrate are outside.

Reference numeral 10 denotes a rotary motor on which the above-mentioned information recording medium 9 is placed and driven to rotate at a predetermined rotational speed.
An optical head is provided with a light source for recording an information signal on a recording layer (not shown) of the information recording medium 9 and generating a light beam for reproducing or erasing the recorded information. The actuator controls the position of the optical head 11 with respect to the recording layer in accordance with a focus control signal or a tracking control signal from a tracking control unit (not shown).

FIG. 4A shows an example of a focus error (FE) signal and a recording (RF) signal measured using a bonding type information recording medium having overcoat layers on both surfaces of the adhesive resin shown in FIG. FIG. 4B shows an example of the FE signal and the RF signal measured using the bonding type information recording medium having no overcoat layer on the second resin substrate shown in FIG. FIG.
As is apparent from FIG. 3, the recording medium having the configuration shown in FIG. 3 has a large warpage angle, so that the FE signal partially increases.
A phenomenon in which the RF signal amplitude in that portion drops and becomes small tends to occur, whereas the recording medium having the configuration shown in FIG. 2 has a small warpage angle, so that the RF signal amplitude and the FE signal are stable.

When the information recording medium 9 has a large warpage as shown in FIG. 3, for example, the optical head 1
In some cases, the FE signal for controlling the focus of No. 1 partially increases, and the RF signal has amplitude unevenness. As a result, for example, a jitter value when forming a recording mark on an adjacent track may be 10% or more. In some cases, the system exceeds the limit in which the actuator 12 can be corrected systematically, which causes a problem that recording or reproduction cannot be performed by a normal recording / reproducing apparatus.

On the other hand, when the information recording medium 9 has a structure with a very small warpage as shown in FIG. 2, for example, both the FE signal and the RF signal for controlling the focus of the optical head 11 on the recording layer are stable. However, the jitter value can be suppressed to about 9% or less, and it is possible to cope with high-density recording / reproducing (that is, a recording medium structure with a narrow track interval).

[0024] Incidentally, the information recording medium applicable to the present invention is not limited to the configuration shown in FIG. 2, for example, the recording layer is 2 or more layers SL provided in the first resin substrate
Recording layer configuration, configuration without reflective layer or protective layer, first resin substrate
No reflective layer, protective layer and dielectric layer are formed on
A first substrate configuration such as a configuration having only one loose recording layer;
A resin substrate, for example, dielectric layer, even reflective layer also properly is a configuration of a second substrate having any one or more of a thin film or thin film similar to those of the protective layer, adhered to the overcoat layer if the information recording medium having on both sides of the adhesive surface in contact with the surface, of course it can be applied to a recording re NamaSo location of the present invention.

[0025]

As it is evident from the foregoing description, according to the recording re NamaSo location of the present invention, since a very small warping of the information recording medium, FE
The signal and the RF signal are stabilized, and an effect that recording, reproduction, and / or erasing with a sufficient margin can be performed even with a normal recording / reproducing apparatus can be obtained.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a main part of an information recording medium recording / reproducing apparatus according to an embodiment of the present invention.

FIG. 2 is a partial sectional view of an information recording medium applied to the information recording apparatus of the present invention.

FIG. 3 is a partial cross-sectional view of a conventional information recording medium.

4A and 4B are waveform diagrams of an RF signal of an information recording medium and an FE signal, FIG. 4A is a waveform diagram of an RF signal of an information recording medium according to an embodiment of the present invention, and FIG. RF signal and FE waveform diagram of recording medium

[Description of Signs] 1 First resin substrate 2 Dielectric layer 3 Recording layer 4 Reflective layer 5 Protective layer 6 Overcoat layer 7 Second resin substrate 8 Adhesive resin 9 Information recording medium 10 Thin film 11 Rotary motor 12 Optical head 13 Actuator 14 Focus control means

Claims (2)

[Claims] 1. A first resin substrate having an organic material overcoat layer laminated on a thin film including a recording layer, and a second resin substrate having an organic material overcoat layer formed thereon via an adhesive resin. A driving unit that rotationally drives an information recording medium having the overcoat layers bonded together, an optical head that emits a light beam that records or reproduces an information signal on the recording layer, and a focus tracking signal of the optical head for the recording layer. A recording / reproducing method for an information recording medium, comprising: focus control means for controlling focus of the generated light beam. 2. A first resin substrate having an organic material overcoat layer laminated on a thin film including a recording layer, and a second resin substrate having an organic material overcoat layer formed thereon via an adhesive resin. A rotation motor that rotationally drives the information recording medium on which the overcoat layers are bonded, an optical head that emits a light beam that records or reproduces an information signal on the recording layer, and a focus tracking signal of the optical head for the recording layer. A recording / reproducing apparatus for an information recording medium, comprising: a focus control circuit for controlling focus of the generated light beam.