JP2006114218A - Optical recording medium recording and/or reproducing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable continuous recording and reproduction to a plurality of layered information parts. <P>SOLUTION: An optical recording medium is used, which has a first recording body 31 having a first semi-transparent information part 31M and a second recording body 32 having a second reflective information part 32M and wherein first and second spiral recording tracks having rotary recording directions one of which goes toward an inner peripheral part from an outer peripheral part and the other of which goes toward the outer peripheral part from the inner peripheral part are concentrically disposed in the first and the second information parts 31M and 32M. The optical recording medium is irradiated with light from a first substrate 31S side in the state that the optical recording medium is rotated in one direction to perform recording and/or reproduction of data continuously to the first and the second information parts 31M and 32M. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical recording medium recording and / or reproducing method.

  In order to increase the amount of information that can be recorded in an optical recording medium such as a disk or card that performs recording or (and) reproduction by light irradiation as a recording medium for recording various information for audio, video, etc. It can be considered that the recording information surface has a multilayer structure.

  For example, in the optical disc, as shown in FIG. 6, information portions 1M and 2M on which information is recorded by information recording pits, for example, are formed on one surface of each of the transparent substrates 1S and 2S. 1M and 2M, for example, the first recording body 1 and the second recording body 2 on which reflection surfaces 1R and 2R are formed by Al deposition are overlapped with the surfaces having the information portions 1M and 2M facing each other. Proposals have been made for a configuration in which the layers are bonded together with the bonding adhesive 3.

  In such an optical recording medium such as an optical disk, in order to read out or reproduce the recorded information with respect to the first and second information sections 1M and 2M, irradiation of the readout light (hereinafter referred to as reproduction light) is performed. The first information part 1M is performed by irradiating the reproduction light 1L from the transparent substrate 1S side, and the second information part 2M is performed by irradiating the reproduction light 2L from the transparent substrate 2S side. . That is, in this case, as the drive device for this optical recording medium, the above-described two-layer information recording unit, that is, the reproducing optical pickup for the first and second information units 1M and 2M are opposed to both surfaces of the optical recording medium. Either a two-optical pickup configuration to be arranged, or a method in which the optical disk is inverted with respect to one optical pickup and each information section is selectively opposed to the optical pickup side and reproduced. become.

  In such a configuration, the two-optical pickup configuration is unavoidable to increase the size of the device, increase the number of parts, and increase the weight. In addition, the one-optical pickup configuration requires a reversing operation of the optical disk, and In order to perform continuous reproduction for the first and second information units 1M and 2M, in order to automate the reversal of the optical recording medium, a large-scale mechanism is required. The increase in score and weight cannot be avoided.

  In order to avoid such an inconvenience, there has been proposed an optical recording medium that enables reproduction on a two-layer information recording unit by light irradiation from the same side of the optical recording medium. This optical recording medium will be described together with its manufacturing method with reference to the process diagram of FIG. 7. In this case, as shown in FIG. 7A, for example, a first information portion 21M having recording pits corresponding to the recording information is formed. A first transparent substrate 21S made of polycarbonate (hereinafter referred to as PC) or the like is formed by injection molding. Then, a translucent optical layer 23, for example, a SiN sputtering layer, is controlled to have the required transmittance and reflectance in the information portion 21M. Then, a second information portion is formed on the first information portion 21M by a photopolymerization method using an ultraviolet light curable resin, so-called 2P method. That is, as shown in FIG. 7C, the stamper 25 having the concave / convex pattern forming the second information part is pressed to the information part 21M of the transparent substrate 21S via the ultraviolet curable resin 24, and in this state, from the transparent substrate 21S side. The ultraviolet curable resin 24 is cured by performing ultraviolet irradiation. Thereafter, as shown in FIG. 7D, the stamper 25 in FIG. 7C is peeled off. In this way, the second information part 22M is formed in the ultraviolet curable resin 24 by transferring the concave / convex pattern of the stamper 25. A reflective film 26 such as an Al vapor deposition film is formed on the second information portion 22, and a protective layer 27 made of a photocurable resin or the like is further coated thereon. Thus, an optical recording medium on which the first and second information portions 21M and 22M are formed is configured.

  Reproduction by light irradiation on the optical recording medium with this configuration is performed from the same side on the transparent substrate 21S side, and as shown in FIG. 7D, reproduction on the first information unit 21M is performed from the transparent substrate 21S side. The first information portion 21M is irradiated with the reproduction light 21L that is focused, information is read out by the reflected light from the first information portion 21M, and the reproduction with respect to the second information portion 22M is also transparent. The reproduction light 22L obtained by focusing the reproduction light 22L on the second information portion 22M is irradiated from the substrate 21S side, and information is read by the reflected light from the second information portion 22M.

  According to this configuration, since both the first and second information recording units can be reproduced by light irradiation from one side, a single optical pickup configuration can be provided, and the optical recording medium can be reversed. Therefore, there is an advantage that the drive device of this optical recording medium can be reduced in size, weight, simplified configuration, simplified assembly, and the like. In the medium, since the formation of one information portion 2M is based on the 2P method, it is necessary to form the information portion 2M in a sheet-like manner, which causes a problem in mass productivity.

  Further, even if the information section has a two-layer structure, a structure that can continuously read information of each layer has not been proposed, and there is a problem that it is difficult to increase the continuous recording or reproduction time.

  In view of the above, the present invention provides an optical recording medium recording and / or reproducing method capable of continuously performing light irradiation for reproduction or (and) recording on a plurality of stacked information units.

  An optical recording medium recording and / or reproducing method according to the present invention includes a first recording body provided on one surface of a light-transmitting first substrate and having a semi-light-transmitting first information section; 2 and a second recording body having a reflective second information portion, and the first information portion and the second information portion have a rotational recording traveling direction. In FIG. 1, spiral-shaped first and second recording tracks are formed, one from the outer periphery to the inner periphery, and the other from the inner periphery to the outer periphery, and the first information on the first substrate is formed. The surface on which the portion is formed and the surface on which the second information portion of the second substrate is formed are opposed to each other, and a transparent layer having a predetermined thickness made of a photocurable transparent resin is interposed therebetween. Thus, the first and second recording tracks are coaxially arranged by joining the first and second substrates. Using these optical recording media configured such that each of these rotational recording traveling directions is in the same direction as viewed from the light incident surface when light is irradiated from the first substrate side, the optical recording medium is set in one direction. In the rotated state, light is irradiated from the first substrate side, and data recording and / or reproduction is continuously performed on the first and second information portions.

  According to another optical recording medium recording and / or reproducing method of the present invention, a first recording body having a semi-light-transmitting first information section on one surface side of a light-transmitting substrate, and a transparent And a second recording body having a reflective second information portion, and one of the first information portion and the second information portion is arranged from the outer peripheral portion to the inner peripheral portion in the rotational recording traveling direction. Spiral first and second recording tracks are formed, the other of which is from the inner periphery to the outer periphery, and the first and second recording tracks are coaxially arranged. Using an optical recording medium configured so that the rotational recording traveling direction is the same when viewed from the other surface side of the substrate when viewed from the light incident surface, the optical recording medium is rotated in one direction. In this state, light is irradiated from the other surface side of the substrate, and the first and second information parts are Data recording and / or reproduction is continuously performed.

  According to the above-mentioned present invention, the 1st recording body in which the 1st information part was each formed, and the 2nd recording body in which the 2nd information part was formed are constituted separately, and joined The first and second information sections are stacked, but the recording tracks of the first information section and the second information section are arranged coaxially as viewed from the light incident surface side. The recording track of the first information section and the recording track of the second information section are in the same direction, and one of them is directed from the inner periphery (center) to the outer periphery. In addition, by adopting a configuration in which the other is directed from the outer peripheral portion to the inner peripheral portion, particularly when each recording track is formed in a spiral shape, the recording or (and) reproduction of both information portions can be performed continuously. So, continuous recording or (and) increase the playback time Rukoto can.

  According to the optical recording medium recording and / or reproducing method of the present invention, the recording tracks of the first information section and the second information section are arranged coaxially, and the first information section is viewed from the light incident surface side. The recording direction of the recording track of the information section and the recording track of the second information section are set in the same direction, and one is directed from the inner peripheral portion (center portion) to the outer peripheral portion, and the other is moved from the outer peripheral portion. By configuring the recording track to be directed toward the inner periphery, especially when each recording track is spiral, the recording or (and) reproduction of both information units can be performed continuously. (And) The reproduction time can be increased.

  Further, as described above, the first recording body and the second recording body, which are formed independently of each other, have a very simple manufacturing and mass production as compared with the case of the 2P method. Become. In addition, since the first recording body and the second recording body are joined together, the mechanical strength can be increased. In the case of a 6 mm thickness configuration, the strength can be improved, and the 0.6 mm thickness configuration can be adapted to the 1.2 mm configuration, so the compatibility of the drive device 1.2 mm disc and 0.6 mm disc This has the effect of facilitating conversion.

  The present invention is applied to an optical recording medium such as a disk or a card that performs recording or (and) reproduction by light irradiation as a recording medium for recording various information for audio, video and the like. FIG. 2 is a schematic cross-sectional view of an embodiment in which the present invention is applied to a so-called ROM (Read Only Memory) type optical disk, in which an information part is formed by concavo-convex recording pits and this information is read out by light irradiation. is there.

  The optical recording medium according to the present invention, as shown in a schematic sectional view in FIG. 2, has a first information portion 31M having a semi-light transmitting property on one surface of a light transmitting first substrate 31S. 3 and a second recording body 32 having a reflective second information portion 32M on one surface of the second substrate 32S as shown in FIG. As shown in FIG. 1, the first and second information units 31 </ b> M and 32 </ b> M are arranged so as to face each other and are bonded via a transparent layer 33.

  Then, the incident surfaces of the reproduction lights 31L and 32L on the optical recording medium and the first and second information units 31M and 32M, that is, the first and the first recorded on the concave and convex pits in the example of FIG. The incident surfaces of the reproduction lights 31L and 32L on the second information sections 31M and 32M are arranged on the side of the first recording body 31 of the optical recording medium (in this example, an optical disk) having the first information section 31M. It is specified on the opposite surface, that is, the back surface.

  The first information unit 31M is configured to be semi-light transmissive as described above, and the reflectance is 20% to 50% and the light transmittance is 30% to 80%.

  In addition, the second information unit 32M is configured to be reflective as described above, and its reflectance is 60% or more.

  In this optical disc, the recording tracks of the first and second information portions are coaxially arranged, and the rotational recording progress direction of the first information portion 31M and the rotational recording progress of the second information portion 32M. The direction is selected in the same direction as seen from the light incident surface side as indicated by arrows in FIG.

  Similarly, as shown in FIG. 4, the recording tracks of the first information section and the second information section are coaxially arranged, and the rotational recording progress direction of the recording track of the first information section 31M and the second information section are the same. As indicated by the arrows, the rotational recording progress direction of the information recording track of the information section 32M is such that one of them is from the outer periphery to the inner periphery and the other is from the inner periphery to the outer periphery, for example, in a spiral shape. Select the direction of rotation recording.

  Further, in the method of manufacturing an optical recording medium according to the present invention, as shown in a schematic cross-sectional view of an example in FIG. 2, the semi-light transmissive first information is formed on one surface of the light transmissive first substrate 31S. As shown in the schematic cross-sectional view of the first recording body 31 having the portion 31M and an example thereof in FIG. 3, the second recording portion 32M having the reflective second information portion 32M on one surface of the second substrate 32S. The recording body 32 is prepared separately.

  As shown in FIG. 1, the first recording body 31 and the second recording body 32 are shown in FIG. 5 as an example in the case where each information section 31M and 32M adopts a recording mode using concavo-convex recording pits. As shown in a schematic cross-sectional view, a transparent resin such as a PC is formed by injection molding using a mold 40. In this case, in forming the first recording body 31, a master stamper 41 in which an information uneven pattern for forming the first information portion 31M is formed in the cavity of the mold 40 is arranged and formed. In forming the second recording body 32, a master stamper 42 in which an information uneven pattern for forming the second information portion 32M is formed in the cavity of the mold 40, and a transparent resin is formed in the cavity. For example, PC is injected and so-called injection molding is performed.

  In these master stampers 41 and 42, each information uneven pattern was sequentially recorded on the inner circumference side, that is, from the center side to the outer circumference side, and in either the clockwise direction or the counterclockwise direction. The other is formed in a pattern, and the other is recorded from the inner circumference side to the outer circumference side opposite to the above, and the rotation direction is sequentially counterclockwise or the clockwise direction opposite to that described above. It is formed into a pattern made.

  These master stampers 41 and 42 can be formed by a known method. That is, for example, a photoresist is applied onto a glass substrate having a mirror surface, for example, and laser light that has been subjected to light modulation such as on / off in accordance with recorded information is rotated relative to the glass substrate, and in the radial direction. Pattern exposure is performed by relatively moving scanning. Thereafter, the photoresist is developed to form a concavo-convex pattern according to pattern exposure, and a metal master, for example, silver plating is performed thereon to produce a disk master. Thereafter, a metal, for example, nickel plating is applied on the disk master, and a metal mask having a concave / convex pattern in which the concave / convex pattern of the disk master is reversed is formed on the surface, and then, for example, nickel plating is performed on the concave / convex pattern of the metal mask. Thus, a mother having a concavo-convex pattern in which the concavo-convex pattern of the metal mask is inverted is formed, and master stampers 41 and 42 in which the concavo-convex pattern of the mother is inverted are similarly formed by plating.

  The pattern exposure according to each recording information for the photoresist on each glass substrate described above for forming each master stamper 41 and 42 described above is performed, for example, from one inner side toward the outer peripheral side and, for example, clockwise. When the exposure corresponding to the recorded information is sequentially performed as the rotation direction, the other pattern exposure is performed according to the recorded information sequentially as the rotation direction from the outer peripheral side toward the inner peripheral portion and in the counterclockwise direction.

  Using the master stampers 41 and 42 produced as described above, the first transparent substrate 31S on which the first information part 31M is formed by injection molding, respectively, and the second on which the second information part 32M is formed. The substrate 32S is formed.

On the first information portion 31M formed in this way, as shown in FIG. 2, a semitransparent film 34 such as SiN or SiO ₂ is formed to a thickness of, for example, 150 mm by vapor deposition, sputtering, or the like as necessary. As described above, the first information portion 31M is an information portion having anti-transmittance with a reflectance of 20% to 50% and a light transmittance of 30% to 80%.

  Further, as shown in FIG. 3, for example, a vapor deposition film having a thickness of about 500 mm is formed on the second information portion 32M so that the reflectivity of the second information portion 32M is 60% or more. It has an information part.

  Then, these substrates 31S and 32S are bonded to each other with the side on which the first information part 31M is formed facing the side on which the second information part 32M is formed, with the transparent layer 33 interposed therebetween. . As the transparent layer 33, for example, a photo-curing transparent resin, for example, an ultraviolet-curing transparent resin, is sandwiched between the substrates 31S and 32S and bonded to each other, and light, for example, ultraviolet light is irradiated from the first transparent substrate 31S side. Harden. In this case, it is assumed that the first transparent substrate 31S and the first information unit 31M are transmissive or semi-transmissive with respect to ultraviolet rays for performing the exposure and curing.

  In this way, the interval between the first and second information portions 31M and 32M is set to a required interval, for example, 40 μm depending on the thickness of the transparent layer 33, and reflection from the information portions 31M and 32M, for example, in the reproduction light. At the same time as setting an interval at which no interference occurs in the light, both substrates, that is, the first recording body 31 and the second recording body 32 are joined together to produce a target optical recording medium.

  In this way, the finally formed optical recording medium has the same rotation when the recording tracks of the first and second information portions 31M and 42M are viewed from the light incident surface, that is, from the substrate 31S side in the above example. The recording travel direction is taken, and one of the recording heads is directed from the inner periphery to the outer periphery, and the other is taken from the outer periphery to the inner periphery.

  Each of the recording tracks of the first and second information sections can be formed in a spiral shape or a concentric ring shape.

  In addition, the substrates 31S and 32S of the first and second recording bodies have a thickness substantially equal to each other, for example, 1.2 mm or 0.6 mm. When doing so, it is possible to effectively avoid the occurrence of deformation such as “warping” due to thermal expansion and contraction due to the influence of the ambient temperature of the optical recording medium by joining these substrates 31S and 32S.

  According to the above-described configuration of the present invention, since the first and second information portions 31M and 32M are formed to be stacked, the information capacity can be increased. Since the information part 31M of the second information part is translucent, the second information part is also irradiated with the reproduction light from the same direction as the irradiation direction of the reproduction light to the first information part 31M. Since the information part 32M can be reached and the reflected light of the information part 32M can be detected, information can be read out by the occurrence of interference caused by, for example, information pits in the information parts 31M and 32M.

  In this case, as described above, the reflectance of the first information part 31M is 20% to 50%, the light transmittance is 30% to 80%, and the reflectance of the second information part is 60% or more. By doing this, the amount of read light for the first information unit 31M and the amount of read light for the second information unit 32M can be made substantially equal, and this allows the output of these information readouts to be output. A circuit for adjustment can be simplified.

  As described above, the recording tracks of the first information unit 31M and the second information unit 32M are arranged coaxially, and the recording track of the first information unit 31M is viewed from the light incident surface side. And the recording progress directions of the recording tracks of the second information section 32 are set in the same direction, and one is directed from the inner peripheral portion (center portion) to the outer peripheral portion, and the other is directed from the outer peripheral portion to the inner peripheral portion. By adopting the configuration of directing, especially when each recording track is spiral, the recording or (and) reproduction of both information portions 31M and 32M can be performed continuously, so that the continuous recording or (and ) The playback time can be increased.

  In the above-described example, the first and second information units 31M and 32M have mainly been described in the case of an optical disc having a ROM configuration with concave and convex recording pits, but the recording mode of these information units is limited to this. Instead, the present invention can be applied to an optical recording medium that can be optically recorded, added, and rewritten. Further, the information units 31M and 32M can be information units based on the same recording / reproduction mode, or can be information units based on different recording / reproduction modes. As these information parts, for example, recording is performed by a phase change between an amorphous state and a crystalline state, and the information part is configured by phase change recording in which the recording is performed by changing optical characteristics, or magneto-optical recording. Various aspects such as a configuration can be adopted.

  In the above-described example, the first and second recording bodies 31M and 32M are configured to be joined. However, it is also possible to have a configuration in which three or more recording bodies are superposed.

  Further, the optical recording medium and the manufacturing method thereof according to the present invention are not limited to the disc, and other various modifications can be made without being limited to the above-mentioned examples such as other card configurations.

  In the present specification, the optical pickup is not limited to the reproduction pickup, but also refers to one having an optical recording function.

It is a schematic sectional drawing of an example of the optical recording medium by this invention. It is a schematic sectional drawing of an example of the 1st recording body which comprises the optical recording medium by this invention. It is a schematic sectional drawing of an example of the 2nd recording body which comprises the optical recording medium by this invention. It is explanatory drawing of the recording advancing direction of each information part of the optical recording medium by this invention. It is sectional drawing of the injection mold of an example of the manufacturing method of the optical recording medium by this invention. It is a schematic sectional drawing of the conventional optical recording medium. FIG. 6A is a cross-sectional view of one process for producing a conventional optical recording medium. FIG. 7B is a cross-sectional view of one process for producing a conventional optical recording medium. C is a cross-sectional view of one step of a conventional method for producing an optical recording medium. FIG. 4D is a cross-sectional view of one step of a conventional method for producing an optical recording medium.

Explanation of symbols

31 1st recording body 32 2nd recording body 31S 1st board | substrate 32S 2nd board | substrate 31M 1st information part 32M 2nd information part 33 Transparent layer

Claims (3)

Provided on one surface of the light-transmitting first substrate and provided on one surface of the second substrate and the first recording body having the semi-light-transmitting first information portion, A second recording body having a second information portion, wherein one of the first information portion and the second information portion is directed from the outer peripheral portion to the inner peripheral portion in the rotational recording traveling direction, and the other Are each formed with spiral first and second recording tracks from the inner periphery to the outer periphery,
The surface of the first substrate on which the first information portion is formed and the surface of the second substrate on which the second information portion is formed are opposed to each other, and is light-curable and transparent. The first and second recording tracks are coaxially arranged by bonding the first and second substrates with a transparent layer made of a resin having a predetermined thickness interposed therebetween. Using an optical recording medium configured so that the traveling direction is the same as viewed from the light incident surface when light is irradiated from the first substrate side,
With the optical recording medium rotated in one direction, light is irradiated from the first substrate side, and data recording and / or reproduction is continuously performed on the first and second information sections. An optical recording medium recording and / or reproducing method characterized in that:   In the optical recording medium, the interval between the first and second information portions is set to an interval that does not cause interference with the reflected light from the first and second information portions depending on the thickness of the transparent layer. The optical recording medium recording and / or reproducing method according to claim 1, wherein: On the one surface side of the light transmissive substrate, a first recording body having a semi-light transmissive first information section, a transparent layer, and a second recording body having a reflective second information section. And
In the first information portion and the second information portion, in the rotational recording traveling direction, one of the first information portion and the second information portion is spirally directed from the outer peripheral portion to the inner peripheral portion and the other from the inner peripheral portion to the outer peripheral portion. Recording tracks are respectively formed, the first and second recording tracks are coaxially arranged, and the respective rotational recording traveling directions are light when the light is irradiated from the other surface side of the substrate. Using an optical recording medium configured to be in the same direction as viewed from the incident surface,
With the optical recording medium rotated in one direction, light is irradiated from the other surface side of the substrate, and data recording and / or reproduction is continuously performed on the first and second information portions. An optical recording medium recording and / or reproducing method characterized in that:

Images