KR20090107993A - Optical information recording medium, optical information reproducing apparatus and optical information recording apparatus - Google Patents

Abstract

PURPOSE: An optical information recording medium, an optical information reproducing device, and an optical information recording device are provided to protect the transparent protection layer and reduce the motor load during rotation of disc. CONSTITUTION: An optical information recording medium(110) comprises a signal substrate(104), a signal recording layer(103), and a transparent protection layer(102). The transparent protection layer of 10~20μm is installed on the signal recording layer. Recording or reproduction of information is performed as light is irradiated onto the signal recording layer through the transparent protection layer. A retention area is formed between a signal area corresponding to the signal recording layer and a central opening of the optical information recording medium. A protrusion(100) is formed on a light incidence surface in the area between the central opening and the retention area.

Description

Optical information recording medium, optical information reproducing apparatus and optical information recording apparatus {Optical information recording medium, optical information reproducing apparatus and optical information recording apparatus}

The present invention relates to a disk-shaped optical data recording medium having a signal recording layer for emitting / receiving light beams to record / reproducing information, and having a transparent protective layer having a thickness of 10 μm to 200 μm disposed on the signal recording layer. The present invention also relates to a method for manufacturing such an optical data recording medium and a method for clamping the optical data recording medium.

Optical discs are widely known as high-capacity data recording media for performing high-density information recording or reproduction using laser light, and are widely used. Such optical discs can be classified into read-only type, incrementally writable (multisession) type, and rewritable type. Generally, the reproduction-only type includes a compact disc (CD) recording music content and a laser disc recording image content such as a movie. The write-once type and the rewritable type are for storing document files and still image files, for example, and are widely used in computer fields and the like.

Such an optical disk is provided with a data layer on one main side of a 1.2 mm thick transparent substrate, a protective film such as an overcoat, or the same protective disk as the transparent substrate. It is common to attach them (see, for example, Japanese Patent Laid-Open No. 2001-093193 and FIG. 1 and Japanese Patent Laid-Open Publication No. 2002-042376, paragraph [0019] and FIG. 1).

Digital Versatile Discs (DVDs), which are large-capacity optical disc media, have made it possible for even end-users to record moving images such as movies and the like on optical discs as well as sound. High density media such as DVDs have been realized by using shorter laser wavelengths and using objective lenses with large numerical apertures (NAs). However, shortening wavelength and increasing NA decrease the tolerance of the tilt, which is the inclination of the disk with respect to the laser beam emission direction.

The allowable value of tilt can be improved by using a thin substrate. For example, in a DVD medium, this means using a 650 nm laser and a NA of 0.6, using a 0.6 mm thick substrate. Since the substrate having a thickness of 0.6 mm is weak in mechanical strength to increase tilt, the DVD disk has a structure in which two substrates are bonded to each other with the data recording surface inside.

Using such a thin layer structure, a transparent reflective layer such as gold or silicon is formed on one data recording surface of two substrates, and a reflective layer of conventional aluminum or the like is formed on the other data recording surface. The substrates are bonded to face each other such that the data recording surface is inward, so that a single-sided, double-layer can read the data recording layer from one side of the substrate, i.e. from the side of the substrate provided with the transparent reflective layer. ) DVD is also configured. In addition, a rewritable DVD having the same two-layer structure but having a rewritable thin film recording layer instead of a metal reflective layer having a data recording surface is also proposed.

In addition, as a method of achieving high density recording, a blue-purple laser of approximately 400 nm wavelength has also been proposed. One method uses a transparent protective layer of approximately 0.1 mm thickness on the recording / reproducing side and forms an ultrafine laser spot using a lens having an NA of about 0.85 to record and / or signal. Is to play the replay. The transparent layer can be formed in the following two ways.

(A) On the signal surface side of a 1.1 mm thick signal board, a transparent substrate slightly thinner than 0.1 mm is attached using an adhesive.

(B) A transparent resin layer having a thickness of about 0.1 mm is coated on the signal surface side of the signal substrate having a thickness of 1.1 mm.

In the method of (A), for example, a polycarbonate sheet produced by casting or the like is used as the transparent substrate. The sheet produced by casting has a small thickness variation of about ± 1 mu m. Since the thickness of the adhesive used to attach the polycarbonate sheet to the signal board is also thin, it can be easily formed with a uniform thickness. As a result, a transparent protective layer having a uniform thickness can be formed on the recording / reproducing side of the disc.

Moreover, in the method of (B), it is difficult to coat with a uniform thickness because of the thickness of the transparent resin, but since it is not necessary to use a sheet produced in an expensive casting process, a high density optical disc can be realized at low cost.

However, in high density optical discs, the transparent protective layer can be easily scratched, and such scratching has a problem that can result in loss in servo control. As the mechanical strength of the transparent protective layer itself increases, the film thickness also increases, which is not suitable for high density recording. Therefore, it becomes difficult to protect the surface from scratching while keeping the transparent protective layer thin.

The data transfer rate during recording and reproduction is higher for high density optical discs than for conventional CD and DVD media, so that the disc turns faster. Therefore, due to the imbalance of the shape and weight of the disk with respect to the spindle hole, it is possible to increase the load of the rotating spindle (motor).

In addition, the high speed rotation of such high density optical discs requires that the disk clamping force be higher than that of CD and DVD discs.

Therefore, the present invention has been made to solve these three problems, and an object of the present invention is to have a surface projection for protecting the transparent protective layer and reducing the motor load during the rotation of the disk, and to provide a larger disk clamping force to the optical data recording medium. To provide an optical data recording medium applicable to the present invention.

In order to achieve the above object, a disc type optical data recording medium having a signal recording layer for reading and / or writing data using light and a transparent protective layer having a thickness of 10 μm to 200 μm on the signal recording layer. A light-incidence that emits light to the signal recording layer in an area between a center hole and a clamping area holding an optical data recording medium when reading and / or writing data to the signal recording layer. and a projection protruding from the surface of the transparent protective layer on the surface side.

Since these protrusions are on the inner circumference side of the clamping region, the protrusions do not interfere (collide with) the optical head. Further, even when the optical data recording medium is placed on the plane with the transparent protection layer facing the plane, the transparent protection layer can be prevented from being scratched because the transparent protection layer is separated from the plane by the projections.

The load on the rotating spindle (motor) due to weight imbalance in the protrusion can also be reduced because the protrusion is located close to the center spindle hole.

Preferably, the protrusion is radially 0.1 mm or more away from the outer edge of the central hole. By such a configuration, the projection can stably prevent the optical data recording medium because it can prevent interference with the center cone used for holding the optical data recording medium in the spindle hole in the disc recording and reproducing drive. Can be clamped

According to another aspect of the present invention, there is provided a disk-type optical data recording having a signal recording layer for reading and / or writing data using light and a transparent protective layer having a thickness of 10 μm to 200 μm on the signal recording layer. The medium includes: a clamping area outside the center hole in the radial direction for holding the optical data recording medium when reading or writing data to the signal recording layer; A signal area outside of the clamping area in a radial direction for performing reading or writing to the signal recording layer; And a projection protruding from the surface of the transparent protective layer in a region between the clamping region and the signal region at the light incidence side of the signal recording layer from which light is emitted for reading and / or writing information. .

Even when the optical data recording medium is placed on the plane with the transparent protection layer facing the plane, the transparent protection layer can be separated from the plane because the projection is close to the signal area, so that the transparent protection layer can be excellently protected. have.

The projection is preferably in an area within 2 mm of radially outward from the outer circumferential edge of the clamping area.

Therefore, since the protrusion is sufficiently separated from the signal area, interference between the protrusion and the optical head can be prevented.

According to another aspect of the present invention, disc-shaped optical data recording having a signal recording layer for reading and / or writing data using light, and a transparent protective layer having a thickness of 10 μm to 200 μm on the signal recording layer. The medium includes: a clamping area outside the center hole in the radial direction for holding the optical data recording medium when reading or writing to the signal recording layer; A signal area outside of the clamping area in the radial direction for executing writing or reading of data to the signal recording layer; And a projection protruding from the surface of the transparent protective layer in a clamping region at the light incident surface side of the signal recording layer from which light is emitted for reading and / or writing information.

Such an optical data recording medium is clamped at both sides of the projection in the clamping area. Therefore, there is no interference (collision) with the optical head and the transparent protective layer is not scratched when the disk is placed on the plane such that the transparent protective layer faces the plane, which means that the projection on the same side of the disk is transparent. This is because the protective layer is held above the plane.

In addition, a larger clamping force can be obtained so that the disk can rotate stably and a good signal can be obtained. The load on the rotating spindle (motor) due to the weight imbalance at the protrusion can also be reduced because the protrusion is located close to the center spindle hole.

It is preferable that the said projection part protrudes in the height of 0.05-0.5 mm from the surface of the said transparent protective layer. Thus, the transparent protective layer does not scratch when the disk is placed on the plane such that the transparent protective layer faces the plane, which is a protrusion protruding sufficiently above the disk surface on the same side so that the transparent protective layer does not contact the plane. Because it is. If the protrusion height is 0.1 mm to 0.3 mm from the surface of the transparent protective layer, scratch-prevention and cost can be further improved.

It is preferable that the wavelength of light for performing recording or reading of information to the signal recording layer is 410 nm or less. Thus, a small beam spot that enables high density recording and reproduction can be realized.

According to another aspect of the present invention, there is provided a signal recording layer that reads and / or writes data using light, a transparent protective layer having a thickness of 10 μm to 200 μm on the signal recording layer, and an optical signal in the signal recording layer. And a disk-shaped optical data recording medium having projections protruding from the surface of the transparent protective layer at the light incident surface side emitting the light.

The manufacturing method includes preparing a first die having a cavity corresponding to the protrusion and a second mold corresponding to the first mold; Placing and pasting the first mold and the second mold together; Injecting a resin between the first mold and the second mold; Curing the resin to form a resin molding having the protrusions; And opening the first mold and the second mold and removing the cured resin molding.

A signal recording layer for reading and / or writing data using light, a transparent protective layer having a thickness of 10 μm to 200 μm above the signal recording layer, and a light incident surface side emitting light to the signal recording layer In another aspect of the method for manufacturing a disc-shaped optical data recording medium having projections protruding from the surface of the transparent protective layer, the substrate for optical data recording medium is ejected using a mold having a cavity corresponding to the projections. It is formed by molding, and the protrusions are simultaneously formed on the substrate.

In the method of manufacturing an optical data recording medium according to the present invention, a cavity corresponding to a desired protrusion shape in a mold is provided, a molten resin is applied to a mold, and a pressure is applied in an injection molding process. All. This manufactures a substrate having a signal pattern transferred from the stamper in molding, and the projections are simultaneously formed on the substrate surface. Therefore, mass production of the optical data recording medium can be improved.

On a signal recording layer for reading and / or writing data using light, a transparent protective layer having a thickness of 10 μm to 200 μm in the signal recording layer, and a light incidence surface emitting light to the signal recording layer. In another aspect of the method for manufacturing a disc-shaped optical data recording medium having protrusions protruding from a surface of the transparent protective layer, the protrusions are formed on the optical data recording medium by adhering a part in the shape of the protrusions. do.

By adhering parts in this manner to form protrusions of desired shape on the surface of the disc, the optical data recording medium manufacturing method can easily form protrusions at desired positions of the disc, thereby improving mass production.

On a signal recording layer for reading and / or writing data using light, a transparent protective layer having a thickness of 10 μm to 200 μm in the signal recording layer, and a light incidence surface emitting light to the signal recording layer. In another aspect of the method for manufacturing a disc type optical data recording medium having protrusions protruding from the surface of the transparent protective layer, the liquid material in the shape of the protrusions is dropped onto the optical data recording medium and cured, The protrusion is formed on an optical data recording medium.

This manufacturing method can easily form protrusions of a desired shape at a desired position on the disk surface by simply changing the method of dropping a liquid material on a substrate. In addition, the time required for forming the projections is short, so that the optical data recording medium having the projections according to the present invention can be manufactured at low cost.

On a signal recording layer for reading and / or writing data using light, a transparent protective layer having a thickness of 10 μm to 200 μm in the signal recording layer, and a light incidence surface emitting light to the signal recording layer. In another aspect of the method for manufacturing a disc-shaped optical data recording medium having protrusions protruding from the surface of the transparent protective layer, the optical data recording medium is formed by a screen printing process using a screen having a desired shape of the protrusions. The protrusion is formed thereon.

Such a manufacturing method can easily form a protrusion having a desired shape at a desired position on the disk surface by simply changing the pattern of the protrusion on the screen. In addition, the time required for forming the projections is short, so that the optical data recording medium having the projections according to the present invention can be manufactured at low cost.

In the optical data recording medium manufacturing method described above, the material used for producing the component adhered to the optical data recording medium surface and the material of the projection formed by screen printing are preferably resin. This makes the material easier to handle, lower cost and improves productivity. It is preferable to use an ultraviolet curable resin, a thermosetting resin, or a pressure-sensitive adhesive as the resin. Each of these materials is inexpensive and readily available.

Preferably, the projection is in an area between a center hole and a clamping area holding the optical data recording medium for reading and / or writing data to the signal recording layer.

This configuration places the projection on the optical data recording medium on the inner circumferential side of the clamping area. Thus, the projections do not interfere (collision) with the optical head and the transparent protective layer does not scratch even when the disk is placed on the plane such that the transparent protective layer faces the plane, which means that the transparent protective layer is not covered by the plane. This is because the projections are on the same side of the disk so as not to come in contact with the disk. Therefore, the reliability of the disc can be guaranteed for a long time.

The projection may include a clamping area for holding the optical data recording medium when reading or writing data to the signal recording layer and a signal area for writing or reading data to the signal recording layer. It is desirable to have.

The projection is preferably in an area within 2 mm of radially outward from the outer circumferential edge of the clamping area. In this case, the optical data recording medium prevents interference between the projection and the optical head, regardless of the recording and reproducing apparatus used.

Preferably, the projection is in a clamping area for holding the optical data recording medium when reading or writing data to the signal recording layer.

In this case, since the disk is clamped at both sides of the projection, interference with the optical head can be prevented and the transparent protective layer can be protected. In addition, a larger clamping force can be applied to the optical data recording medium.

Preferably, the protrusion is formed at a height of 0.05 to 0.5 mm from the surface of the transparent protective layer. Therefore, since the protrusion protrudes sufficiently from the transparent protective layer by such a configuration, the protrusion prevents the transparent protective layer from contacting the plane even when the disk is placed on the plane, so that the transparent protective layer is scratched. There is no Therefore, a more reliable optical data recording medium can be manufactured.

If the height of the protrusion is 0.1 to 0.3 mm from the surface of the transparent protective layer, it is possible to further improve scratch prevention and cost.

Another aspect of the present invention provides a signal recording layer for reading and / or writing data by emitting light using an optical head having a numerical aperture of 0.7 to 0.9, and 10 µm to 200 above the signal recording layer. A clamping method of a disc type optical data recording medium having a transparent protective layer having a thickness of μm. The optical data recording medium includes: a clamping area outside the central hole in the radial direction to hold the optical data recording medium when reading or writing to the signal recording layer; A signal area outside of the clamping area in the radial direction for executing writing or reading of data to the signal recording layer; And a projection protruding from the surface of the transparent protective layer in a clamping region at the light incidence side of the signal recording layer from which light is emitted for reading and / or writing information. The clamping method holds the optical data recording medium on both sides of the projection when performing writing or reading of data to the signal recording layer of the optical data recording medium.

By retaining the optical data recording medium on both sides of the projection, the disk clamping method can apply a larger clamping force, and the disk can rotate stably, so that a good signal can be obtained.

The area for clamping at both sides of the projection on the light incident side is preferably in a radius region having a radius of 11 mm to 16.5 mm.

It is preferable that the optical data recording medium is clamped by holding the optical data recording medium on both sides of the projection on the light incidence side and holding the projection.

Therefore, by clamping the disk in two regions opposite the projections and applying pressure directly to the projections, a larger clamping force can be applied.

In the optical data recording medium according to the present invention, the projection does not interfere with the optical head and the transparent protective layer is in contact with the plane when the disk is placed on the plane with the transparent protective layer side down. Since the projections are prevented, the transparent protective layer can be protected from scratching.

In addition, the load on the rotating spindle (motor) due to the weight imbalance at the projections is also reduced because the projections are located close to the center spindle hole.

The clamping method of the optical data recording medium according to the present invention holds the optical data recording medium in one or both clamping areas of the projection. Therefore, the optical data recording medium can be stably held and rotated during recording and reproduction, so that consistent recording and reproduction and a good signal can be obtained.

The projections can be easily formed by the manufacturing method of the optical data recording medium of the present invention, thereby improving the productivity of the optical data recording medium.

As described above, in the optical data recording medium of the present invention, by including the projections without interfering with the optical head and including the projections, the transparent protective layer is separated from the plane even when the transparent protective layer is placed on the flat surface. Scratches do not occur.

Moreover, since there is a projection in a portion close to the spindle hole, the load on the rotating spindle (motor) due to the weight imbalance of the projection can be reduced.

Other objects of the present invention in addition to the realization of the present invention will become apparent from the following detailed description and claims.

(First embodiment)

1 is a side view showing a preferred embodiment of the optical data recording medium of the present invention. As shown in FIG. 1, the optical data recording medium 110 has a protrusion 100 formed between the inner circumferential side of the clamping area CA and the outer edge of the spindle hole 101. FIG. 1A is a cross-sectional view of the optical data recording medium 110, and FIG. 1B is a view of the optical data recording medium 110 viewed from above.

The outer diameter of the optical data recording medium 110 is 120 mm. The clamping area CA is an area in which the optical data recording medium 110 is clamped and held when recording and / or reproducing data in the signal recording layer. The inner diameter D _CAI of the clamping region CA is 22 mm, and the outer diameter D _CAO is 33 mm.

In addition, the transparent protective layer 102 is for protecting the signal recording layer 103. For example, a light beam having a wavelength of 405 nm is emitted from the optical head through the transparent protective layer 102, and focuses on the signal recording layer 103 for recording and reproduction.

The thickness of the transparent protective layer 102 is 100 micrometers, for example. A signal pit or groove formed in the signal area SA of the signal substrate 104 is formed, and a signal recording layer 103 is formed thereon. The inner diameter D _SAI of the signal area SA is 42 mm, and the outer diameter D _SAO is 119 mm. The signal recording layer 103 may be formed of a multilayer film including a phase-change film called GeSbTe, a multilayer film including a pigment film, and an alloy thin film.

The diameter Dc of the spindle hole 101 is 15 mm, the inner diameter D _ti of the protrusion 100 is 18 mm, the radial width is 1 mm, and the protrusion 100 from the surface of the transparent protective layer 102. ) Has a height of 0.3 mm. It is preferable that the width | variety of the radial direction of the projection part 100 is 0.2-1 mm. The width is preferably at least 0.2 mm to ensure sufficient mechanical strength.

It is preferable that the height of the projection part 100 from the surface of the transparent protective layer 102 is 0.1-0.5 mm. If the height of the protrusion 100 from the surface of the transparent protective layer 102 is 0.1 mm or more, even if the transparent protective layer 102 is placed on the plane with the protrusion 100 facing down, the transparent protective layer 102 is It will not be in contact with the plane and can prevent scratching.

In addition, although the inner diameter D _ti of the protrusion 100 is 18 mm, the inner edge of the protrusion 100 only needs to be 0.1 mm or more away from the outer edge of the spindle hole 101. That is, the inner diameter of the protrusion 100 should be larger than the diameter (Dc + 0.2) mm, the outer diameter should be smaller than the inner diameter (D _CAI ) of the clamping area (CA). If the inner diameter D _ti is larger than (Dc + 0.2) mm, the disc can be stably clamped and rotated during recording and playback without interfering with the centering cone and the projection 100 of the recording or reproducing apparatus. And a good signal can be guaranteed.

Table 1 shows the height of the protrusions 100 from the surface of the transparent protective layer 102 and the effects thereof. As an index indicating the effect of the projections in Table 1, the amount of scratches on the surface of the transparent protective layer and the disk being picked up when the transparent protective layer 102 is placed on a flat surface with the bottom down (pick up) Ease of use).

[Table 1] Projection height and its effect

Height of the projection from the transparent protective layer (mm) 0 0.05 0.1 0.2 0.3 0.4 0.5 Surface scratches Bad (NG) usually Good Good Good Good none Ease of lifting Bad (NG) Difficulty Difficulty Good Good Very good Very good

When the height of the projection from the transparent protective layer 102 is Omm, that is, when there is no projection 100, the transparent protective layer may be excessively scratched, and it is difficult to lift the disk from the plane. If the height of the projection is 0.05mm, the degree of scratching and the ease of lifting the disk may be slightly improved, but the protective margin may not be sufficient, and the transparent protection is necessary to improve the resistance to scratching. It should be treated in the same way as hardening the layer surface.

If the protrusions are 0.1 mm, the scratches are considerably improved, and the scratches are almost free. When the projections are 0.02 to 0.03 mm, the transparent protective layer hardly scratches, and it is easy to lift the disk.

If the protrusion is 0.4 mm, the transparent protective layer has little scratches, and the disk can be easily lifted. If the protrusions are 0.5 mm, the transparent protective layer is not scratched at all, and the disc can be lifted very easily.

Even if the height of the projection 100 from the surface of the transparent protective layer is higher than 0.5 mm, the degree of scratching on the transparent protective layer and the ease of lifting the disc no longer improve as compared with the case of 0.5 mm. In addition, since the height of 0.5 mm or more increases the volume, it is not preferable in consideration of the cost of the required material.

If the diameter D _C of the spindle hole 101 is approximately 15 mm, the diameter of the protrusion 100 is within 17.5 to 22 mm, and the height of the protrusion 100 from the surface of the transparent protective layer 102 is 0.3 mm or less, Including the above effects, the following three advantages can be satisfied ((2) and (3) below are the above effects).

(1) The protrusion 100 does not interfere with the chuck used to clamp the disc during recording and playback of the optical disc.

(2) Even when the disk is bent or placed on a flat surface, scratches can be prevented from occurring in the transparent protective layer 102.

(3) Even when the disk is bent, the disk can be easily lifted from the plane.

First, paragraph (1) is demonstrated. 12A to C show that an optical data recording medium for recording or reproducing a disc is chucked. 12 illustrates a general simplified chucking method used in DVDs or other media. As shown in FIG. 12A, an optical data recording medium 110 is mounted on the chuck 1200. The jaw 1201 of the chuck extends outwardly by a spring 1202. When the diameter D _C of the spindle hole 101 of the optical data recording medium 110 is 15 mm, the jaw 1201 has an outer diameter D _H of approximately 17 mm such that the periphery of the spindle hole 101 is chucked reliably. Is set to. In addition, if the diameter D _H of 17 mm, the mechanical strength of the jaw 1201 is also guaranteed.

As shown in Fig. 12B, the optical data recording medium 110 contacts the jaw 1201. At this time, if the protrusion 100 is an outer region having a diameter of 17.5 mm or more from the center of the disk, the protrusion 100 will be out of the range where the jaw 1201 touches. Therefore, the projection part 100 and the jaw 1201 do not contact each other, nor are they loaded. When pressure is applied to the top of the disk to push down, the spring 1202 is forced to contact, and the jaw 1201 is directed towards the center of the chuck 1200 until it passes through the disk's spindle hole 101. Move. At this time, the spring 1202 extends outward, and the jaw 1201 is pushed out.

As a result, as shown in FIG. 12C, the optical data recording medium 110 is clamped by the chuck 1200. As shown in FIG. 1, the inner diameter D _CAI of the clamping region CA is 22 mm. Thus, although the disk 110 is held in an area outside the inner diameter D _CAI , the protrusion 100 and the chucking surface 1203 do not interfere because the outer diameter of the protrusion 100 is smaller than 22 mm.

In addition, since the inner diameter of the clamping area is 22 mm in a conventional optical disc such as a DVD medium, even when the optical data recording medium 110 is incorrectly chucked using a conventional chuck for a DVD medium, the projection portion 100 may be a jaw of the chuck. Interference with the chucking surface can be prevented.

When the diameter D _C of the spindle hole 101 is about 15 mm, when the protrusion 100 is within an area of 17.5 to 22 mm in diameter, the largest chucking force is applied to the optical data recording medium 110. Even when the simplified chuck 1200 is used, interference between the protrusion 100 and the chuck 1200 including the jaw 1021 can be avoided.

Although (2) and (3) were demonstrated with reference to the said Table 1, it demonstrates further in detail using FIG. When the thickness of the transparent protective layer 102 is 100 mu m, the maximum value of deflection allowed for the optical data recording medium 110 is 0.35 degrees. This is because when the warpage is 0.35 degrees or more, the error rate during recording and reproduction increases to such an extent that error correction is impossible.

FIG. 13 shows a case where the optical data recording medium 110 having a maximum deflection of 0.35 degrees lies on the plane P. At this time, the transparent protective layer 102 faces the plane P. As shown in FIG. In addition, the optical data recording medium 110 is generally bent on the outer periphery (ie, the outer periphery of the disc center area of 33 mm diameter) than the clamping area CA. In this case, if the optical data recording medium 110 has the projection 100 lying in the circumferential region of 17.5 to 22 mm in diameter, and the height of the projection 100 from the surface of the transparent protective layer 102 is 0.3 mm, the optical data The outer edge E and the plane P of the recording medium 110 do not contact each other. That is, since the outer diameter of the optical data recording medium 110 is 120 mm, (60-33 / 2) * TAN (0.35 degrees) = 0.27 mm, the optical data recording medium 110 is closer to the plane P. However, if the height from the surface of the transparent protective layer 102 to the top of the protrusion 100 is 0.3 mm, the outer edge E does not contact the plane P.

When attempting to lift the disk 110 by hand, the disk 110 can be easily lifted due to the increased contact area between the finger and the outer edge E of the disk 110. In addition, since the surface of the transparent protective layer 102 also does not contact the plane P, scratches due to contact with the plane P can be prevented.

The height of the protrusion 100 from the surface of the transparent protective layer 102 may be determined according to the bending allowed by the optical data recording medium 110. As an example, when the maximum value of the deflection allowed for the optical data recording medium 110 is 0.35 degrees, the above-mentioned effect can be sufficiently achieved by the height of the projection 100 from the surface of the transparent protective layer 102 being 0.3 mm or less. have.

14A and 14B show a case where there is a step between the surface of the transparent protective layer 102 and the surface of the clamping region CA. 14A shows optical data recording in which the surface of the transparent protective layer 102 is concave 25 µm further from the surface of the clamping region CA such that the transparent protective layer 102 is farther from the recording / reproducing head than the clamping region CA. An example of a medium is shown. 14B shows a difference in the case where the surface of the clamping area CA is formed more concave 25 µm from the surface of the transparent protective layer 102 so that the surface of the clamping area CA is closer to the recording / reproducing head.

In the case of FIG. 14A, the height of the protrusion 1400 from the surface of the clamping region CA is set so that the height of the protrusion 1400 from the surface of the transparent protective layer 102 is 0.3 mm or less as in FIG. 12. Is adjusted to 0.275 mm or less. In addition, in the case of Fig. 14B, in order to make the height of the projection 1400 from the surface of the transparent protective layer 102 0.3 mm or less, the height of the projection 1400 from the surface of the clamping area CA is 0.325 mm. Adjust to the following. As mentioned above, in either case, the height of the projection part 1400 from the transparent protective layer 102 surface can be 0.3 mm or less.

Further, in order to better prevent the interference between the protrusion 1400, the chucking surface 1203, and the chuck 1200 than the example shown in FIG. 12, the protrusion 1400 has a diameter of 17.5 to 21 mm or less as shown in FIG. Can be placed in the circumferential area. At this time, if the inner diameter D _CAI is 22 mm, a clearance of 0.5 mm can be obtained in the radial direction between the protrusion and the clamping region CA.

In addition, as shown in FIG. 13, if the disk is not largely bent, as shown in FIG. 14, the height of the protrusion 1400 may be adjusted regardless of the presence or absence of a step between the transparent protective layer surface and the clamping region. ) It can be 0.2 mm or less from the surface.

At this time, interference between the protrusion 1400 and the chucking surface 1203 and the chuck 1200 can be avoided, so that the depth G of the chuck 1200 can be made shallow to about 0.25 mm, and the design of the chuck 1200 can be avoided. Can increase the degree of freedom.

2 shows an example of the cross-sectional shape of the projection. As in FIG. 2, the protrusions may be spherical (rectangular) 201, trapezoidal 202, elliptical 203, semicircular 204, or triangular. In addition, the shape of such a protrusion is not limited to the shape shown in FIG. 2, and any protrusion may be used as long as it protrudes onto the surface of the transparent protective layer.

3 is an example showing the shape of the projection when viewed from above. FIG. 3A shows a rectangular configuration, FIG. 3B shows a configuration with multiple discontinuous projections, and FIG. 3C shows a configuration with a ring broken in part. In the configuration shown in Fig. 3B, projections 302 such as four discontinuities are placed at intervals of 90 degrees in the circumferential direction.

In addition, in the broken ring configuration shown in Fig. 3C, three arc-shaped protrusions 303 are placed at intervals of 120 degrees in the circumferential direction on the same circular path.

When multiple discontinuous protrusions are provided as in the configuration in Fig. 3B or 3C, the number of protrusions need not be limited.

In addition, the shape of the projection part in plan view is not limited to that shown in FIG. In particular, the protrusion may be formed in any shape if it protrudes from the surface of the transparent protective layer and is in the circumferential region of the inner diameter (D _C +0.2) to the outer diameter (D _CAI ).

FIG. 4 shows an example of the optical data recording medium 410 when the configuration of the clamping area from the spindle hole is different from that of FIG. This disc differs from the case of FIG. 1 in that the transparent protective layer 402 covers the clamping area CA but is not around the spindle hole 401. Therefore, the inner diameter D _CV of the transparent protective layer 410 is D _CV ≦ D _CAI . The protrusion 400 is between the spindle hole 401 and the inner diameter of the clamping area CA.

The total height Tt of the protrusion 400 is

T _t = T _tcv + (transparent protective layer thickness)

Here, T _tcv is the height above the surface of the transparent protective layer 402, and in this example, T _tcv is 0.1 to 0.5 mm.

It is also possible that no transparent protective layer is formed in the clamping region CA.

By providing a projection projecting from the surface of the transparent protective layer on the light incidence side between the spindle hole and the clamping region of the optical data recording medium, the following effects can be obtained.

The projections cannot be placed anywhere on the optical disc, and in particular, they must be placed where there is no contact between the projections and the optical head. In the optical data recording medium according to the embodiment of the present invention, the projection is placed in the area between the spindle hole and the clamping area CA. When reading and / or writing data to the signal recording layer, the optical head is always on the outer peripheral side of the clamping area CA. Therefore, there is no contact between the optical head and the projection, the projection is on the inner circumferential side of the clamping region, and is separated from the optical head by the clamping region CA.

A method of manufacturing such a protrusion in accordance with the present invention is shown in FIG. 5 using an injection molding process as an example.

As shown in Fig. 5A, a pair of dies 500 are prepared, and a stamper 501 is set in one die. One side of the mold holding the stamper 501 has a cavity 502. This cavity 502 forms the protrusion in the desired shape.

As shown in FIG. 5B, the mold 500 is closed and a molten resin 510 is injected. At this time, the molten resin 510 soaks into the signal 517 pattern and the cavity 502. Thereafter, the mold is cooled and the spindle hole 511 is stamped as shown in FIG. 5C to obtain a signal substrate 516 having a signal 517 formed on its surface. After that, a signal recording layer is formed on the surface of the signal 517 to form a transparent protective layer as shown in FIG. In order to manufacture the optical data recording medium 110 as shown in FIG. 1, a transparent protective layer is formed from the protrusion 515. Since the transparent protective layer is also accumulated on the protrusion 515, the protrusion having the same shape is also formed in the transparent protective layer.

6 shows how a member having the shape of a desired protrusion is secured to the disk surface with an adhesive. In this case, the projection 600 of the desired shape adheres to the optical data recording medium 601, i.e., the plane of the disk without the protruding surface. For example, pressure-sensitive adhesives, UV-cured resins, thermosetting resins and the like can be used. As the material of the projection 600, it is preferable that the material is lightweight, easy to handle, and inexpensive. Therefore, the resin is suitable.

A material for adhering the protrusion 600 to the portion of the protrusion 600 that contacts the protrusion-less disk 601 may be coated in advance. Alternatively, the part in contact with the non-projection disc 601 may be heated and melted to bond. The projection 600 may be made of metal. Using the method shown in Fig. 6, a flat optical data recording medium 601 without protrusions is produced in one process, and the member forming the protrusions is made into a desired shape in a separate process, and then a specific desired shape is formed. The protrusion which has is able to adhere | attach on a disk surface.

7 shows a method of dripping and curing a liquid resin. As in FIG. 7A, the liquid resin 700 is dropped by a nozzle 701 at a predetermined position of the non-protrusion disk 601. At this time, the protrusion-free disk 601 may be dropped or rotated, or may be dropped while moving the nozzle 701. As the material of the liquid resin 700, an ultraviolet curable resin, a thermosetting resin, or the like is preferable. After dropping, the resin can be cured to obtain the protrusion 715 having a desired configuration as shown in FIG. 7B. Using a disk as shown in Fig. 4, resin is dropped onto the signal substrate.

In addition, projections may be formed of liquid resin using screen printing. In this case, the printing screen is formed like a projection of a desired shape, and the liquid resin is screen printed on the disk surface. In the case of FIG. 7, since it is not necessary to prepare and process a separate protrusion member, the protrusion can be formed more economically than in FIG.

As described above, the optical data recording medium according to the first embodiment of the present invention has one or more protrusions located on the surface between the inner circumferential side of the clamping area CA and the outer edge of the spindle hole, whereby the protrusions are recorded. Or, do not contact the optical head during playback.

In addition, since the projections allow the transparent protective layer to be in sufficient contact with the plane without being in contact with it, even when the disk is placed on the plane with the transparent protective layer below, surface scratching can be prevented.

In addition, since the protrusion is close to the spindle hole, it is possible to minimize the effect of the weight unbalance in the protrusion. Thus, a stable and high quality signal can be obtained.

(2nd Example)

8 shows an optical data recording medium 810 having a projection 800 in an area between the clamping area CA and the signal area SA. Fig. 8A is a sectional view and Fig. 8B is a plan view seen from the transparent protective layer 802 side of the disc. The inner and outer diameters of the clamping area CA and the signal area SA are the same as in the first embodiment. The thickness of the transparent protective layer 802 is also the same as in the first embodiment. In this example, the inner diameter D _ti of the protrusion 800 is 33 mm (= D _CAO ) and the outer diameter D _to is 35 mm. The height T _tcv of the protrusion 800 is 0.25 mm. In addition, the protrusion 800 is formed on the surface of the signal substrate 804.

Fig. 9 shows a partial view when the optical disc is being recorded and / or reproduced.

When using a 0.7-0.9 NA optical head, such as a 0.85 NA optical head, to record or play back a high density optical disc with a 0.1 mm thick clear protective layer on the laser input side (read / write side) of the disc, the operating distance (WD: The distance between the optical head and the dense optical disk, called the working distance, is generally very small, typically 0.1-0.4 mm. For example, ISO M 2002 Technical Digest ThB.1, published by the International Symposium on Optical Memory, recommends a working distance of 0.4 mm or less.

In this case, since the working distance WD is short, the optical head can easily hit the transparent protective layer of the disk when the focusing servo is disturbed by external factors such as vibration of the disk surface. Can be. The high NA used as a high density optical disc means that dust on the surface of the transparent protective layer can easily disturb the focus servo. When the focus servo is off track, the optical head can easily collide with protrusions on the disk surface. To prevent this, a shield that protects the lens is needed on the surface of the optical head. The thickness of this shield (approximately 0.1 mm) reduces the working distance to 0.3 mm or less. As the working distance of the optical head increases, the outer diameter of the lens also increases. The outer diameter f of the lens with a working distance of 0.4 mm is 6-8 mm (including the lens holder).

In the case of recording and reproducing a signal area having an inner diameter D _SAI as shown in FIG. 9, the lens holder 900 has a lens holder in an area between the clamping area CA and the signal area SA. Forced to enter the same amount as the radius (R) of. For example, for NA O.85, the actual working distance (WD) of the lens is as small as 0.2 to 0.3 mm. That is, in the case of the optical data recording medium as shown in FIG. 8, the optimum height T _tcv of the protrusion varies depending on the position of the protrusion.

The height T _tcv of the projection 800 is considered next.

The closer the protrusion is to the inner diameter D _SAI , the closer to the lens holder 900 is. Therefore, the height T _tcv must be made small. In addition, since the outer diameter D _to of the projection 800 is 35 mm, there is a distance of 3.5 mm from the inner diameter D _SAI = 42 mm. If the actual working distance WD of the lens is 0.2 mm, since the radius R of the lens holder is about 3 mm, the distance between the lens holder 900 and the protrusion 800 has a space of 0.5 mm. If the working distance WD is 0.3 mm, the radius R is about 4 mm, but since the height T _tcv is 0.25 mm, the projection 800 does not collide with the lens holder 900.

As described above, when there is a projection in the area between the clamping area CA and the signal area SA, it is necessary to consider the operating distance WD of the lens. However, if the height T _tcv is 0.1 to 0.3 mm, the projection 800 does not collide with the lens holder.

It is also clear that the surface protection performance of the transparent protective layer can also be achieved.

As described in the second embodiment of the present invention, regardless of the case where the transparent protective layer is not present in the clamping region CA as shown in FIG. 8 or when there is a transparent protective layer as shown in FIGS. 1 and 4. The protrusion may be in an area between the clamping area CA and the signal area SA.

The protrusions in the second embodiment of the present invention can be manufactured using the same method and material as described in the first embodiment. According to the inner diameter of the stamper, it is necessary to form a cavity in the stamper by the injection molding method as shown in FIG. For example, when the inner diameter of the stamper is smaller than 33 mm, the thickness of the stamper is increased to form a cavity of the desired depth and configuration in the stamper by etching or machining. As shown in FIG. 10, the protrusion 1001 may be formed on the signal substrate, and the transparent protective layer 1010 may be formed thereon to form the surface protrusion 1000. In addition, a protrusion may be formed on the optical data recording medium as shown in FIG. 8 by a mold process as shown in FIG. 5.

The shape and configuration of the protrusions can be the same as those described in the first embodiment. As described in the second embodiment of the present invention, when there are protrusions in the area between the clamping area CA and the signal area SA, especially when there are protrusions within 2 mm on the outer circumferential side of the clamping area CA, recording is performed. And when the optical data recording medium is placed on a plane so that the transparent protective layer of the disc faces the plane, since the collision of the projection and the optical head during the reproduction can be prevented, and the surface of the disc is not in contact with the surface on which it is placed by the projection. Even surface scratches can be prevented.

(Third Embodiment)

As a third embodiment of the present invention, an optical data recording medium in which the projection is in the clamping area CA is shown in FIG. 11A is a cross-sectional view of the disk.

The inner diameter D _ti and the outer diameter D _to of the protrusion 1100 are defined by the following relationship.

D _CAI ≤D _ti <D _to ≤ D _CAO

With this configuration, since the projections make a sufficient gap between the planes of the transparent protective layer 1102, even when the optical data recording medium 1110 lies on the plane so that the transparent protective layer 1102 faces the plane. , Can prevent scratching.

In addition, since the optical head does not reach the clamping region CA, it is possible to prevent collision between the optical head and the protrusion.

In the present embodiment, the thickness, the inner diameter D _CAI , and the outer diameter D _CAO of the transparent protective layer are the same as in the first embodiment.

The width of the protrusion 1100 and the height from the surface of the transparent protective layer 1102 are also the same as in the first embodiment, and are in the ranges of 0.2 to 1 mm and 0.1 to 0.5 mm, respectively.

Unlike the first and second embodiments, in the third embodiment, a disc drive clamps the optical data recording medium 1110 at both sides of the protrusion 1100. This is possible except in the case of D _CAI = D _ti or D _to = D _CAO . 11B and 11C illustrate two different ways of clamping the optical data recording medium 1110 on both sides of the projection 1100.

In FIG. 11B, the clamp 1120 applies pressure to the disk in the clamping regions on both sides of the protrusion 1100. In this case, since there is a channel in the clamping member that provides clearance as much as the projection 1100, the disk can be held with sufficient force despite the projection 1100.

In FIG. 11C, the clamp 1130 applies pressure to the disk in both clamping regions of the protrusion 1100 and also pressures the protrusion 1100. This method can apply pressure to a larger area of the disk than the method of Fig. 11B, which makes the disk clamping even better.

Since the optical data recording medium can be stably held and rotated at a sufficient pressure during recording and playback, stable recording and playback performance and a good signal can be obtained.

In the present embodiment, the disk is clamped at both sides of the protrusion 1100, but may be maintained only in the region between the inner diameter D _CAI and the inner circumferential edge of the protrusion 1100, or the outer diameter D _CAO and the protrusion ( It may be maintained only in the region between the outer peripheral edges of 1100.

Although this third embodiment has been described with reference to the configuration shown in FIG. 11, the configuration may be similar to those of FIGS. 4 and 8. That is, the disk may be used in a form in which the transparent protective layer is not formed in the clamping region CA or in a disk in which the clamping region CA has no transparent protective layer and there is no step between the signal substrate and the surface of the transparent protective layer.

The protrusion 1100 of the third embodiment may be formed using the same materials and methods as described in the first and second embodiments described above.

The shape and configuration of the projections can be the same as in the first embodiment.

The clamping of the optical data recording medium according to the present invention is not limited to holding the disk as a chucking jaw in the clamping area CA on only one side of the disk as in FIGS. 12A and 15 in FIG. 12A. In particular, the optical data recording medium can be clamped from both sides of the disc. This is shown in FIG. 16 and is a sectional view in which the optical data recording medium 1600 is clamped in the clamping area CA from above and below the disk by the upper clamp 1605 and the lower clamp 1606. In this example, the protrusion 1601 is placed in the clamping area CA, and both regions of the protrusion 1601 are supported by the lower clamp 1606 at the laser incident side of the disc.

Although not specifically mentioned in the above embodiment, the material of the signal board is preferably a plastic such as polycarbonate, norbornene resin or polyolefin resin.

In addition, the transparent protective layer may be formed by attaching a sheet film thinner than a desired thickness with an adhesive or coating with a liquid resin. When the thin sheet film is attached with an adhesive, an ultraviolet curable resin, a thermosetting resin, a pressure sensitive adhesive, or the like may be used as the adhesive.

In the case of coating with a liquid resin, an ultraviolet curable resin or a thermosetting resin can be used as the liquid resin.

Although the present invention has been described as a preferred embodiment with reference to the accompanying drawings, various modifications and changes will be apparent to those skilled in the art. Such modifications and variations are intended to be included within the scope of the present invention unless they depart from the scope of the invention as defined by the appended claims.

1A is a cross sectional view of an optical data recording medium having a projection according to a first embodiment of the present invention, and FIG. 1B is a plan view of the disk.

2A to 2E are partial sectional views showing possible protrusion shapes.

3A to 3C are views showing the configuration of various protrusions when viewed from above.

FIG. 4 is a view showing an optical data recording medium whose configuration of the area from the spindle hole to the clamping area is different from that of FIG.

5A to 5C are sectional views showing the first manufacturing method of the optical data recording medium having the projections according to the present invention.

6 is a view showing a second manufacturing method of an optical data recording medium having a projection according to the present invention;

7A to 7B show a third manufacturing method of an optical data recording medium having protrusions according to the present invention.

8A is a partial sectional view of an optical data recording medium having a projection according to a second embodiment of the present invention, and FIG. 8B is a partial plan view of the same disk.

Fig. 9 is a partial sectional view showing reading and / or writing of data to a data recording layer of an optical data recording medium having a projection according to a second embodiment of the present invention.

10 is a view showing an example of a method of forming a protrusion in a method of manufacturing an optical data recording medium according to a second embodiment of the present invention.

11A to 11C are cross-sectional views showing a method of clamping an optical data recording medium having protrusions according to a third embodiment of the present invention.

12A-12C are partial cross sectional views of chucking an optical data recording medium for performing reading and / or writing of data to a data recording layer.

Fig. 13 is a partial sectional view showing a case where the curved optical data recording medium is placed on a plane;

14A to 14B show an example of an optical data recording medium having a step between the transparent protective layer surface and the clamping area CA surface.

Fig. 15 is a partial sectional view showing an optical data recording medium having a small projection.

Fig. 16 is a partial sectional view showing an optical data recording medium according to the third embodiment when it is clamped from the top and bottom of the disc.

Claims (5)

In an optical information recording medium having a center hole and a signal substrate, a signal recording layer, and a transparent protective layer having a thickness of 10 μm or more and 20 μm or less provided on the signal recording layer, Recording or reproducing of information is performed by irradiating light to the signal recording layer through the transparent protective layer, There is a holding area in the area between the signal area and the center hole corresponding to the area where the signal recording layer is formed, On the light-incidence surface side of the region between the center hole and the holding region, there is a projection projecting more than the surface of the transparent protective layer, And the projection is formed of the same material as that of the signal substrate and is made of a material different from that of the transparent protective layer. The method of claim 1, The transparent protective layer is formed so as to cover the signal area and the holding area, wherein the area in which the transparent protection layer is formed on the signal substrate is separated from the area in which the protrusion is formed. The method of claim 1, The transparent protective layer is formed so as to cover the signal area and the holding area, and there is a space between the inner peripheral end of the transparent protective layer and the projection. . The method of claim 1, And the transparent protective layer is formed so as to cover the signal area and the holding area, and the protrusion is not in contact with the transparent protective layer. A manufacturing method for producing the optical information recording medium according to any one of claims 1 to 4, or A program having a process for executing the manufacturing method, or Manufacturing equipment for realizing the above manufacturing method.

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