JP4777302B2 - Optical information recording medium and optical information recording medium driving apparatus - Google Patents

Description

  The present invention provides an optical system in which information is recorded by prepits consisting of at least one of concave and convex, two or more information recording layers in which one or more thin films are laminated on the prepits, and a reproducing apparatus An optical information recording medium dedicated to multilayer reproduction having the above-mentioned pre-pit length including a length shorter than the resolution limit length, or a length including a length shorter than the optical system resolution limit length of the reproducing device in the thin film The present invention relates to a multilayer recording type optical information recording medium having two or more information recording layers on which content is recorded by forming a recording mark, and an optical information recording medium driving device for driving these optical information recording media It is.

  Conventionally, when one method (for example, CD: Compact Disk) is standardized in an optical information recording medium, various variations (ROM: Read Only Memory, RW: ReWritable, RE: REwritable, RAM) in the standard. : Random Access Memory etc.) has also been standardized. For this reason, a reproducing apparatus adapted to the above-described method has to be adapted to these various variations. Furthermore, in recent years, variations with a plurality of information recording layers have been standardized in DVDs (Digital Versatile Disks) and BDs (Blue-ray Discs) in order to increase the capacity. Therefore, the reproducing apparatus has to cope with more and more variations.

  As means for solving this problem, there is a method of reproducing contents after discriminating disc variations during reproduction. Although there are various methods for determining the above, there is a technique disclosed in Patent Document 1, for example, as a method for determining the number of information recording layers.

  In Patent Document 1, as shown in FIGS. 9A and 9B, a mechanism for identifying the number of information recording layers of the optical information recording medium 200 and a means for identifying are described.

  Specifically, as shown in FIG. 9A, the optical information recording medium 200 is a two-layer optical information recording medium, and is an information recording layer far from the reproduction light incident surface among all two information recording layers. A certain second information recording layer 204 has an extended area E that is a wider area than the first information recording layer 203 closer to the reproduction light incident surface. The first information recording layer 203 is made of a translucent reflective film, while the second information recording layer 204 is made of a reflective film including the extended region E.

  In Patent Document 1, the light emitted from the light irradiation means 211 toward the two-layer optical information recording medium 200 is incident from the back surface of the reproduction light incident surface of the optical information recording medium 200 and is made of a reflective film. The extended area E is irradiated. The number of information recording layers is identified as to whether the optical information recording medium 20 has one layer or two layers according to the presence or absence of reflection of incident light. Specifically, it can be determined whether the optical information recording medium is the two-layer optical information recording medium 200 shown in FIG. 9A or the single-layer information recording medium shown in FIG. It has become.

  However, Patent Document 1 has a demerit that another discrimination mechanism, that is, a light irradiation unit 211 and a light detection unit 212 is required on the back side of the reproduction light incident surface for discrimination.

  Therefore, as a more general technique, the details will be described later. At the start of reproduction, after the reproduction optical head approaches the reproduction light incident surface of the optical information recording medium from the standby position, focus is applied (reproduction is requested). There is a discriminating means using the fact that the reproduction light is focused on the information recording layer. This technique utilizes the fact that the S-characteristic of the focus error signal indicating the presence of the information recording layer is detected when the reproducing optical head approaches the reproducing light incident surface of the optical information recording medium from the standby position. Based on the S-characteristics, the number of information recording layers is determined by detecting the number of signal recording layers through which the laser light condensing position by the objective lens provided in the light irradiation means has passed.

  Further, in this technique, it is possible to determine which of the ROM, RW, RE, and RAM is based on the magnitude of the reflectance. As described above, the reproducing apparatus has been adapted to various variations of the optical information recording medium.

  Also, in recent years, in optical information recording media, it is increasingly required to increase the information recording density in order to process a huge amount of information such as images, and super-resolution technology has been proposed as a solution. . Super-resolution technology is a special thin film on the information recording layer of an optical information recording medium that has a mark length (determined by the laser wavelength and the numerical aperture of the optical system) that is less than the optical system resolution limit of the playback device. This is a technology that reproduces with a small laser spot by reproducing with a high reproduction laser power, and this enables recording using a smaller mark length, so that a substantial recording density is achieved. To increase. This means that the reproduction technology is a problem when the density is increased, and not the recording technology. Furthermore, a multilayer super-resolution technique combined with the above-described multilayered information recording layer is being proposed.

Note that many optical information recording media using super-resolution technology (hereinafter referred to as “super-resolution optical information recording media”) use the heat generated in the thin film by the reproduction light to limit the optical system resolution limit. In order to reproduce a signal with a mark length equal to or shorter than the length (hereinafter referred to as “super-resolution reproduction”), a normal optical information recording medium incapable of super-resolution reproduction (hereinafter referred to as “non-super-resolution optical information recording medium”). ) Reproduction light having higher power than that of reproduction light is required. In addition, since heat is generated in the thin film, the multilayer super-resolution optical information recording medium often has a lower transmittance of the first information recording layer closer to the reproduction light incident surface than the multilayer non-super-resolution optical information recording medium.
Japanese Laid-Open Patent Publication No. 9-50649 (published February 18, 1997)

  However, in the playback device using the conventional optical information recording medium discriminating method described above, when the variation using the multi-layer super-resolution technology which is newly proposed as described above is added, all variations can be sufficiently handled. It has the problem that it cannot be done. This is because, in the above-described two methods, even though the number of information recording layers can be determined, various variations already exist, so the thin film provided in the information recording / reproducing layer causes super-resolution. This is because it is impossible to determine whether the information recording layer is a super-resolution reproduction film or a non-super-resolution reproduction film based on the reflectance.

  For details of the reason, when reproducing a multi-layer super-resolution optical information recording medium, the multi-layer super-resolution optical information recording medium is divided into a first information recording layer and a second information recording layer like a conventional two-layer non-super-resolution optical information recording medium. In the case of an optical information recording medium (hereinafter referred to as “case 1 structure”) where the thin film regions are substantially equal and substantially overlapped, the second information recording layer is provided in the second information recording layer as in Patent Document 1. The following description will be divided into the case of an optical information recording medium in which the thin film region is wider than the thin film region provided in the first information recording layer (hereinafter referred to as “case 2 structure”).

  First, the case 1 structure will be described. A normal non-super-resolution optical information recording medium reproducing apparatus first identifies an optical information recording medium as two layers by the above-described method, and then focuses on the information recording layer for tracking (rotating optical information recording medium). Reproduction is started in a state where reproduction light follows concentric circles called tracks required for reproduction of the information recording layer provided on the medium or irregularities arranged in a spiral shape. By the way, in the optical information recording medium, generally, no standard is defined for the reproducing method of the reproducing apparatus. Therefore, for example, when reproducing a two-layer information recording medium, there may be a reproducing apparatus that starts reproduction by first focusing on the second information recording layer that is an information recording layer far from the reproduction light incident surface. There is sex.

  In general, the reproducing apparatus suppresses the reproduction light power at the start of reproduction to the minimum in order to reduce power consumption. Therefore, even when reproducing a double-layer super-resolution information recording medium, it cannot be determined whether or not the optical information recording medium is a super-resolution optical information recording medium. In many cases, it is not a high reproduction light power suitable for a medium but a low reproduction light power suitable for a two-layer non-super resolution optical information recording medium. Therefore, the low-power reproduction light suitable for the two-layer non-super-resolution optical information recording medium is transmitted through the first information recording layer of the two-layer super-resolution optical information recording medium having a lower transmittance than the above-described non-super-resolution optical information recording medium. Thus, the second information recording layer is irradiated. Thereafter, the light reflected by the second information recording layer is transmitted again through the first information recording layer of the two-layer super-resolution optical information recording medium and detected as return light by the detector, so that the amount of return light is insufficient, There may be a problem that tracking is not applied.

  Next, the case 2 structure will be described. In addition, since it is the same as that of case 1 structure when focusing on the part which the thin film provided in the 1st information recording layer and the 2nd information recording layer overlaps, after that, it permeate | transmits the thin film of the 1st information recording layer. Only the case where the reproduction of the double-layer super-resolution optical information recording medium is started at a position where the reproduction light can be irradiated to the first information recording layer without performing the above will be described.

  In the above case, the reproducing apparatus determines that the optical information recording medium is a single layer, and the reproducing light having a power suitable for the single-layer non-super-resolution optical information recording medium is irradiated to the second information recording layer for the reason described above. By the way, the reflectance of the second information recording layer of the super-resolution optical information recording medium is lower than that of the non-super-resolution optical information recording medium when the reproduction light is irradiated with a power suitable for the super-resolution optical information recording medium as described above. Even when the first information recording layer having the transmittance is transmitted twice, it is higher than the reflectance of the information recording layer of the single-layer non-super resolution optical information recording medium so that the amount of return light can be maintained. For this reason, there is a possibility that the amount of return light becomes excessive and focus or tracking is not applied.

  As described above, the conventional method for dealing with variations of the non-super-resolution information recording medium at the start of reproduction has many problems with the super-resolution information recording medium.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide light that can easily identify the type of a super-resolution optical information recording medium or a non-super-resolution optical information recording medium. An object is to provide an information recording medium and an optical information recording medium driving device.

  In order to solve the above problems, the optical information recording medium of the present invention has an information recording layer in which information is recorded by prepits consisting of at least one of concave and convex, and one or more thin films are laminated on the prepits. An optical information recording medium dedicated to multilayer reproduction, having two or more layers and having the above-mentioned pre-pits having a length shorter than the optical system resolution limit of the reproducing apparatus, The near first information recording layer has a reflectance equal to that of a single-layer read-only optical information recording medium having only prepits longer than the optical system resolution limit length of the reproducing apparatus, or the optical system solution of the reproducing apparatus. It has a reflectance equal to that of a single-layer recording type optical information recording medium in which information is recorded only by a recording mark longer than the image limit length, and is different from the first information recording layer in other information recording layers. Thin film It is characterized in that also has a wide range of areas.

  In a multi-layer super-resolution optical information recording medium, each information recording layer is recorded with a pre-pit having a length shorter than the optical system resolution limit length of the reproducing apparatus, and each information recording layer is not It has characteristics different from those of non-super-resolution optical information recording media such as a higher reflectance than the super-resolution optical information recording media. Therefore, in a reproducing apparatus capable of reproducing both the non-super-resolution optical information recording medium and the super-resolution optical information recording medium, the optical information recording medium set in the reproducing apparatus is a non-super-resolution optical information recording medium or a super-resolution optical information recording medium. Therefore, there is a problem in that the reproduction condition of each information recording layer cannot be set.

  On the other hand, in the present invention, in the multi-layer super-resolution optical information recording medium, the first information recording layer has a non-super-resolution light longer than the length of the optical system resolution limit of the reproducing device for the non-super-resolution optical information recording medium. Recording having a reflectance equal to that of a single layer reproduction-only optical information recording medium having only prepits for the information recording medium or longer than the length of the optical system resolution limit of a reproducing apparatus for a non-super-resolution optical information recording medium It has a reflectance equal to that of a single-layer recording type optical information recording medium on which information is recorded only by marks.

  For this reason, even if it is a multi-layer super-resolution optical information recording medium, the first information recording layer can be focused as long as the reproducing apparatus can reproduce the single-layer non-super-resolution optical information recording medium. It is possible to identify whether the optical information recording medium set in is a non-super-resolution optical information recording medium or a super-resolution optical information recording medium. For example, it can be identified as a super-resolution medium because it cannot be reproduced.

  In the present invention, the first information recording layer has a wider area than the thin films of the other information recording layers. For this reason, medium information indicating whether the optical information recording medium is a non-super-resolution optical information recording medium or a super-resolution optical information recording medium can be recorded in this wide area.

  Therefore, it is possible to provide an optical information recording medium that can easily identify the type of optical information recording medium dedicated to multilayer reproduction, which is a super-resolution optical information recording medium or a non-super-resolution optical information recording medium.

  Further, in order to solve the above problems, the optical information recording medium of the present invention is formed by forming a recording mark having a length shorter than the optical system resolution limit length of the reproducing device on the thin film. A multilayer recording type optical information recording medium having two or more information recording layers on which content is recorded, and the first information recording layer closest to the reproduction light incident surface is the length of the optical system resolution limit of the reproduction apparatus. The optical system resolution limit of the reproducing apparatus has a reflectance equal to that of a single-layer reproduction-only optical information recording medium having only one concave or convex, or both concave and convex prepits. It has a reflectance equal to that of a single-layer recording type optical information recording medium in which content is recorded only by a recording mark longer than the length, and is different from the thin film of another information recording layer different from the first information recording layer. Wide area It is characterized by having.

  According to the above invention, in the multilayer recording type optical information recording medium, is the first information recording layer recorded with the pre-pits for the non-super-resolution optical information recording medium, even if it is a multilayer super-resolution optical information recording medium? Alternatively, since the content is recorded only with the recording mark for the non-super-resolution optical information recording medium, if the reproducing apparatus can reproduce the single-layer non-super-resolution optical information recording medium, the first information recording layer can be focused, The information recorded on the optical information recording medium can be reproduced.

  Therefore, it is possible to provide an optical information recording medium that can easily identify the type of a multilayer recording type optical information recording medium, which is a super-resolution optical information recording medium or a non-super-resolution optical information recording medium.

  In the optical information recording medium of the present invention, the first information recording layer has a wider area on the inner peripheral side than a thin film of another information recording layer different from the first information recording layer. Is preferred.

  As a result, even if it is a multi-layer super-resolution optical information recording medium, a lead-in in which information for reproducing various optical information recording media is recorded as long as the reproducing apparatus can reproduce the single-layer non-super-resolution optical information recording medium. Since the first information recording layer can be focused on the innermost area where the area is generally provided, it is possible to efficiently reproduce information recorded on the optical information recording medium. .

  In the optical information recording medium of the present invention, the type of the optical information recording medium is set in a wider area than the thin film of the other information recording layer different from the first information recording layer in the first information recording layer. It is preferable that the medium information shown is recorded only with prepits longer than the length of the optical system resolution limit of the reproducing apparatus. The type of optical information recording medium refers to the type of super-resolution optical information recording medium or non-super-resolution optical information recording medium.

  That is, in the present invention, the medium information indicating the type of the super-resolution optical information recording medium or the non-super-resolution optical information recording medium is present in the area expanded from the other information recording layers in the first information recording layer. The recording is performed only with prepits longer than the optical system resolution limit length of the reproducing apparatus.

  Therefore, even a multilayer super-resolution optical information recording medium can be focused on a wide area in the first information recording layer as long as the reproducing apparatus can reproduce the single-layer non-super-resolution optical information recording medium. It is possible to identify the type of the optical information recording medium whether it is an information recording medium or not. If the type of optical information recording medium can be identified, the number of layers can be determined by detecting the S-characteristic of the focus error signal indicating the presence of the information recording layer.

  In the optical information recording medium of the present invention, reproduction information for reproducing the content recorded on each information recording layer is stored in the first information recording layer from the length of the optical system resolution limit of the reproducing apparatus. However, it is preferable to record only long prepits. Note that the reproduction information for reproducing the content recorded on each information recording layer refers to reproduction information for setting an optimum reproduction condition for each information recording layer. The optimum reproduction conditions are, for example, reproduction power and reproduction speed.

  As a result, reproduction information for reproducing the content recorded in each information recording layer is recorded only in the pre-pits for the non-super-resolution optical information recording medium in either the wide area or the data area in the first information recording layer. Therefore, even if it is a multi-layer super-resolution optical information recording medium, if it is a reproducing apparatus capable of reproducing a single-layer non-super-resolution optical information recording medium, the first information recording layer can be focused. Reproduction information for reproducing the content recorded in the information recording layer can be reproduced. As a result, reproduction can be started under optimum reproduction conditions in each information recording layer, and reproduction light power adjustment in each information recording layer becomes unnecessary, and the time until reproduction in each information recording layer can be shortened.

  In the optical information recording medium of the present invention, the information is recorded on each information recording layer in a wider area than the thin film of the other information recording layer different from the first information recording layer in the first information recording layer. It is preferable that the playback information for playing back the content is recorded with only prepits longer than the optical system resolution limit of the playback device.

  As a result, reproduction information for reproducing the content recorded in each information recording layer is recorded only in the pre-pits for the non-super-resolution optical information recording medium in a wide area in the first information recording layer. Even if it is a resolving optical information recording medium, if it is a reproducing apparatus capable of reproducing a single-layer non-super-resolution optical information recording medium, the first information recording layer can be focused, and at that time, the information is recorded on each information recording layer. Reproduction information for reproducing the content can be reproduced. As a result, reproduction can be started under optimum reproduction conditions in each information recording layer, and reproduction light power adjustment in each information recording layer becomes unnecessary, and the time until reproduction in each information recording layer can be shortened.

  Further, in order to solve the above problems, the optical information recording medium of the present invention is an information recording in which information is recorded by prepits consisting of at least one of concave and convex, and one or more thin films are laminated on the prepits. A first information recording medium having a number of layers equal to or more than one and having the above pre-pit shorter than the optical system resolution limit of the reproducing apparatus, the optical information recording medium dedicated to multilayer reproduction and closest to the reproducing light incident surface The layer has a reflectance equal to that of a single-layer read-only optical information recording medium having only a prepit longer than the optical system resolution limit length of the playback device, or from the length of the optical system resolution limit of the playback device. In addition, the first information recording layer has medium information indicating the type of the optical information recording medium, and has a reflectance equal to that of a single-layer recording type optical information recording medium in which information is recorded only with a long recording mark. And reproduction information for reproducing the content recorded on the information recording layer, is characterized in that it is only recorded for longer pre-pit than the length of the optical system resolution limit reproduction apparatus. The type of optical information recording medium refers to the type of super-resolution optical information recording medium or non-super-resolution optical information recording medium. Further, the reproduction information for reproducing the content recorded on each information recording layer refers to reproduction information for setting an optimum reproduction condition for each information recording layer. The optimum reproduction conditions are, for example, reproduction power and reproduction speed.

  According to the above invention, in the multi-layer super-resolution optical information recording medium, the first information recording layer is a single layer having only the pre-pits for the non-super-resolution optical information recording medium longer than the length of the optical system resolution limit of the reproducing apparatus. Single-layer recording type in which information is recorded only with a recording mark for a non-super-resolution optical information recording medium having a reflectance equal to that of a reproduction-only optical information recording medium or longer than the optical system resolution limit length of the reproducing apparatus The reflectance is equal to that of the optical information recording medium.

  For this reason, even if it is a multi-layer super-resolution optical information recording medium, if the reproducing apparatus can reproduce the single-layer non-super-resolution optical information recording medium, the first information recording layer can be focused and its contents can be read. it can.

  In the present invention, the first information recording layer includes optical information included in the reproducing apparatus that includes medium information indicating the type of the optical information recording medium and reproduction information for reproducing the content recorded on each information recording layer. Only prepits longer than the system resolution limit are recorded.

  For this reason, even if it is a multi-layer super-resolution optical information recording medium, the single-layer non-super-resolution light is recorded by the medium information indicating the type of the optical information recording medium recorded with the pre-pits for the non-super-resolution optical information recording medium on the first information recording layer. If the reproducing apparatus can reproduce the information recording medium, the first information recording layer can be focused, and the optical information recording medium set in the reproducing apparatus after reading the contents can be a non-super-resolution optical information recording medium or super It is possible to identify which type of the resolution optical information recording medium.

  Further, even if the information recording layer is a multi-layer super-resolution optical information recording medium, the information recorded on the first information recording layer is recorded with pre-pits for the non-super-resolution optical information recording medium. If the reproducing apparatus can reproduce the single-layer non-super resolution optical information recording medium, the first information recording layer can be focused, and reproduction information for reproducing the content recorded on each information recording layer at that time Can be played. As a result, reproduction can be started under optimum reproduction conditions in each information recording layer, and reproduction light power adjustment in each information recording layer becomes unnecessary, and the time until reproduction in each information recording layer can be shortened.

  Therefore, it is possible to provide an optical information recording medium that can easily identify the type of optical information recording medium dedicated to multilayer reproduction, which is a super-resolution optical information recording medium or a non-super-resolution optical information recording medium.

  Further, in order to solve the above problems, the optical information recording medium of the present invention records content by forming a recording mark having a length shorter than the optical system resolution limit length of the reproducing apparatus on the thin film. The first information recording layer closest to the reproduction light incident surface is a concave longer than the length of the optical system resolution limit of the reproduction apparatus. Alternatively, it has a reflectance equal to that of a single-layer read-only optical information recording medium having only one of convex, or both concave and convex prepits, or longer than the optical system resolution limit length of the reproducing apparatus. The first information recording layer has medium information indicating the type of the optical information recording medium, and has the same reflectance as that of the single layer recording type optical information recording medium in which content is recorded only by the recording mark. Information recording layer And reproduction information for reproducing the recorded content is characterized by being recorded only in longer pre-pit than the length of the optical system resolution limit reproduction apparatus.

  According to the above invention, in the multilayer recording type optical information recording medium, the first information recording layer has non-super-resolution optical information regardless of whether it is a multilayer super-resolution optical information recording medium or a multilayer super-resolution optical information recording medium. Since the content is recorded only with the recording marks for the recording medium pre-pits or the recording marks for the non-super resolution optical information recording medium, any playback apparatus capable of reproducing the single-layer non-super resolution optical information recording medium can be used. The information recording layer can be focused. At that time, the type of the optical information recording medium can be identified, and at the same time, reproduction information for reproducing the content recorded on each recording layer can be reproduced. Therefore, reproduction can be started under optimum conditions in each information recording layer, and reproduction light power adjustment in each information recording layer becomes unnecessary, and the time until reproduction in each information recording layer can be shortened.

  Therefore, it is possible to provide an optical information recording medium that can easily identify the type of a multilayer recording type optical information recording medium, which is a super-resolution optical information recording medium or a non-super-resolution optical information recording medium.

  The optical information recording medium driving apparatus of the present invention is an optical information recording medium driving apparatus for reproducing the optical information recording medium described above, in order to solve the above problems, and is recorded on the first information recording layer. The reproduction is performed using the reproduction information of each of the other information recording layers.

  According to the above invention, it is possible to provide an optical information recording medium driving device that can easily identify the type of super-resolution optical information recording medium or non-super-resolution optical information recording medium.

  In the optical information recording medium of the present invention, as described above, the first information recording layer closest to the reproducing light incident surface has only a prepit longer than the length of the optical system resolution limit of the reproducing apparatus. It has the same reflectivity as that of an optical information recording medium or the same reflectivity as that of a single-layer recording type optical information recording medium in which information is recorded only by a recording mark longer than the optical system resolution limit length of the reproducing apparatus In addition, it has a wider area than a thin film of another information recording layer different from the first information recording layer.

  In the optical information recording medium of the present invention, as described above, the first information recording layer closest to the reproduction light incident surface has a single layer having only prepits longer than the optical system resolution limit length of the reproduction apparatus. Reflectivity equal to that of a single-layer recording type optical information recording medium that has the same reflectance as that of a reproduction-only optical information recording medium or that records information only with a recording mark that is longer than the optical system resolution limit length of the reproducing apparatus. The first information recording layer includes medium information indicating the type of the optical information recording medium and reproduction information for reproducing the content recorded on each information recording layer. It is recorded only with pre-pits longer than the optical system resolution limit.

  Further, as described above, the optical information recording medium driving device of the present invention performs reproduction using reproduction information of each of the other information recording layers recorded on the first information recording layer.

  Therefore, it is possible to provide an optical information recording medium and an optical information recording medium driving device that can easily identify the type of super-resolution optical information recording medium or non-super-resolution optical information recording medium.

  An embodiment of the present invention will be described with reference to FIGS. 1 to 8 as follows.

  First, a reproduction system for a multilayer optical information recording medium that is a super-resolution optical information recording medium of the present embodiment will be described. In the present embodiment, for example, the configuration of a reproduction system for reproducing a four-layer optical information recording medium will be described below with reference to FIG. However, the reproduction system is not necessarily limited to four layers, and can reproduce other multi-layer optical information recording media. In addition, the reproduction system 100 according to the present embodiment can reproduce both the super-resolution optical information recording medium and the non-super-resolution optical information recording medium.

  As shown in FIG. 2, in the reproduction system 100 as the optical information recording medium driving apparatus of the present embodiment, a disk-shaped optical information recording medium 10 (see FIG. 4 for the cross-sectional structure) is It is rotationally driven at a predetermined speed. The disk drive motor 101 is controlled by a motor control circuit 109. Information is read from the optical information recording medium 10 that is rotationally driven in this manner by the optical pickup 102.

  The optical pickup 102 is moved in the radial direction of the optical information recording medium 10 by the driving force of the feed motor 111. The feed motor 111 is controlled by a feed motor control circuit 108. The rotation speed of the feed motor 111 is detected by a speed detector 112.

  A speed signal obtained from the speed detector 112 is supplied to the feed motor control circuit 108.

  The optical pickup 102 includes an objective lens 102a. The objective lens 102a is supported so as to be movable in a focusing direction (optical axis direction) and a tracking direction (radial direction of the optical information recording medium 10). The position of the objective lens 102a is controlled in the focus direction when a control signal is supplied to the focus drive coil 102c, and the position is controlled in the tracking direction when a control signal is supplied to the tracking drive coil 102b. .

  The laser control circuit 103 drives a semiconductor laser oscillator 102f in the optical pickup 102 to generate laser light. In this semiconductor laser oscillator 102f, the light amount of the generated laser light is detected by the light amount detector 102g, and the detection result is fed back to the laser control circuit 103 so that laser light with a constant light amount is generated. It is controlled. The laser light generated from the semiconductor laser oscillator 102f passes through the collimator lens 102e and is bent at a right angle to the half prism 102d. Then, any one of the information recording layers (of the optical information recording medium 10) is formed by the objective lens 102a. The light is condensed on a first information recording layer 3 and a second information recording layer 4 which will be described later. Reflected light from the optical information recording medium 10 travels backward through the objective lens 102a and travels straight through the half prism 102d, and then is received by the photoelectric converter 102j via the condenser lens 102h and the cylindrical lens 102i. The photoelectric converter 102j includes four photodetectors 102j1 to 102j4 that generate an electrical signal corresponding to the amount of received light. In this case, the alignment direction of the photodetectors 102j1 and 102j2 and the alignment direction of the photodetectors 102j3 and 102j4 correspond to the tracking direction of the optical information recording medium 10, and the alignment direction of the photodetectors 102j1 and 102j4 and the alignment direction of the photodetectors 102j2 and 102j3 This corresponds to the tangential direction of the information recording medium 10.

  The electrical signal output from the photodetector 102j1 of the photoelectric converter 102j is supplied to one end of each of the adder circuits 113a and 113d via the amplifier circuit 114a, and the electrical signal output from the photodetector 102j2 passes through the amplifier circuit 114b. The electric signal supplied to one end of each of the adder circuits 113b and 113c and output from the photodetector 102j3 is supplied to each other end of the adder circuits 113a and 113c via the amplifier circuit 114c and output from the photodetector 102j4. The electric signal is supplied to the other ends of the adder circuits 113b and 113d via the amplifier circuit 114d. The output signal of the adder circuit 113 a is supplied to the inverting input terminal − of the differential amplifier circuit 104, and the output signal of the adder circuit 113 b is supplied to the inverting input terminal + of the differential amplifier circuit 104. The differential amplifier circuit 104 calculates a difference between the output signals of both the adder circuits 113 a and 113 b to generate a focus error signal and supplies it to the focus control circuit 105. The focus control circuit 105 generates a control signal to be given to the focus drive coil 102c so that the input focus error signal becomes 0 level, and focus servo for the objective lens 102a is performed.

  Here, the focus error signal output from the differential amplifier circuit 104 indicates the condensing position of the laser beam by the objective lens 102a at its initial position (usually below the first information recording layer 3 in the optical information recording medium 10). When the focus search process is performed by sequentially moving in the focus direction from the position farthest from the optical information recording medium 10 in the optical axis direction, the condensing position of the laser light by the objective lens 102a is shown in FIG. Each time it passes through each information recording layer (first information recording layer 3, second information recording layer 4, etc.), an S-characteristic is drawn as shown in FIG.

  For example, at the start of reproduction, first, reproduction light corresponding to the single-layer optical information recording medium is generated by the semiconductor laser oscillator 102f in the optical pickup 102.

  Next, the condensing position of the laser beam by the objective lens 102a is set to the drive upper limit position (usually farthest from the optical information recording medium 10 in the optical axis direction) from the initial position facing the lead-in area R in the optical information recording medium. Position). Then, the number of information recording layers of the optical information recording medium is recognized by counting the number of times that the focus error signal exceeds a predetermined reference voltage + V0.

  Next, the reproduction light power is changed to the reproduction light power determined based on the number of information recording layers included in the non-super-resolution optical information recording medium. Then, the condensing position of the laser beam by the objective lens 102a is moved from the drive upper limit position to the initial position with the changed reproduction light power. At that time, the gain of the amplifier included in the focus control circuit 105 or the like is changed so that the voltage value of the focus error signal detected from the information recording layer first subjected to the focus search process becomes an appropriate value.

  For example, when the focus search process is performed on the fourth information recording layer, the number of times that the focus error signal exceeds the predetermined reference voltage + V0 is counted. When the focus servo is turned on when the center level is reached, the focus search process for the fourth information recording layer is completed.

  FIGS. 7A and 7B show the condensing position of the laser beam by the objective lens 102a (FIG. 7A) and the focus error signal (FIG. 7B) when the focus search is performed as described above. )).

  For example, when a layer jump from the second information recording layer 4 to the fourth information recording layer is performed, the focus servo is temporarily turned off, and the laser light from the second information recording layer 4 to the fourth information recording layer is emitted from the objective lens 102a. Are sequentially moved, and the number of times the focus error signal output from the differential amplifier circuit 104 exceeds a predetermined reference voltage + V0 is counted. When the focus servo is turned ON at the time when the operation reaches the center level, the layer jump process is completed (not shown) because it is almost the same process as the focus search process.

  In the state where the focus search processing is performed, the phase difference detection circuit 107 causes the phase difference between the sum of the output signals of the photodetectors 102j1 and 102j4 of the photoelectric converter 102j and the sum of the output signals of the photodetectors 102j2 and 102j3. Is detected, and the detection result is supplied to the tracking control circuit 106 as a tracking error signal.

  The tracking control circuit 106 generates a control signal to be applied to the tracking drive coil 102b based on the input tracking error signal, and performs tracking servo for the objective lens 102a. Then, the optical information recording medium 10 is reproduced while the tracking servo is being performed. Then, the electrical signals output from the adder circuits 113c and 113d are summed by the adder circuit 113e and converted into a digital signal by the data reproduction circuit 110.

  Further, the value of the focus error signal of the reproduction system 100 increases as the reflectance increases. Furthermore, the reflectance of each variation (ROM, RE, RW, RAM, etc.) of the optical information recording medium is often different. In view of this, in the reproduction system 100 of the present embodiment, the value of the focus error signal is compared with a plurality of predetermined reference voltage values corresponding to the reflectivity of each variation of the optical information recording medium, thereby recording the optical information. Media variations can also be identified.

  FIG. 8 is a flowchart showing the multilayer optical information recording medium reproducing process. That is, first, after loading the information recording medium, the information recording medium is rotated at a predetermined number of revolutions by the disk drive motor 101 (S1). Next, the optical pickup 102 is moved to a position facing the lead-in area R of the information recording medium, and a focus search process is performed on a desired layer (S2). Next, tracking processing is performed (S3), and information reproduction processing is performed (S4).

  Next, the optical information recording media 10, 20, and 30 of the present embodiment will be described below. In the following description, the optical information recording medium 20 (hereinafter referred to as “case 1 structure”) in which the thin film regions of the first information recording layer and the second information recording layer are substantially equal to each other, 2 Compared with the optical information recording medium 30 (hereinafter referred to as “case 2 structure”) in which the thin film region provided in the information recording layer is wider than the thin film region provided in the first information recording layer. To explain. 1 is a sectional view of an optical information recording medium 10, FIG. 2 is a sectional view showing an optical information recording medium 20 having a case 1 structure, and FIG. 3 is a sectional view showing an optical information recording medium 30 having a case 2 structure. is there.

  As shown in FIG. 1, the optical information recording medium 10 of the present embodiment includes a light transmitting layer 1, a first information recording layer 3, an intermediate layer 2, and a second information recording layer 4 in order from the reproduction light incident surface side. The substrate 5 is laminated. The optical information recording medium of the present invention is not limited to the two information recording layers, and can have more information recording layers.

  Specifically, as shown in FIG. 4, the translucent layer 1 includes a polycarbonate film 1 a having a thickness of 55 μm and a transparent adhesive resin layer 1 b having a thickness of 20 μm. The first information recording layer 3 includes a first reproducing film 3a made of zinc oxide having a thickness of 206 nm and a first light absorbing film 3b made of silicon (Si) having a thickness of 9 nm.

  The intermediate layer 2 is made of a transparent ultraviolet curable resin having a thickness of 25 μm. The second information recording layer 4 includes a second reproducing film 4a made of zinc oxide having a thickness of 180 nm and a second light absorbing film 4b made of SUS304 having a thickness of 50 nm.

  On the upper side of the second information recording layer 4, a substrate 5 made of a polyolefin resin is laminated.

  Information is recorded on the first reproduction film 3a of the first information recording layer 3 by prepits that are at least one of concave and convex. In the present embodiment, only one thin film of the first light absorption film 3b is laminated on the first reproduction film 3a. However, the present invention is not limited to this, and a multilayer is laminated on the first reproduction film 3a. It is also possible to do.

  Here, as shown in FIG. 1, the first information recording layer 3 of the present embodiment is provided from the inner peripheral side of the second information recording layer 4, and as a result, the first information recording layer 3 is Compared with the second information recording layer 4, it has a lead-in area R as a wide area which is an extended area. In this embodiment, a pre-pit (minimum pre-pit length: 0.15 μm) made of, for example, a concave and a convex longer than the optical system resolution limit length of the reproduction system 100 is used for the lead-in area R. Medium information is recorded. The medium information refers to medium information indicating the type of super resolution optical information recording medium or non-super resolution optical information recording medium.

  Further, in the data area D provided on the outer peripheral side of the lead-in area R in the first information recording layer 3 and the data area D of the second information recording layer 4, for example, prepits (minimum prepits) (not shown) formed of concaves and convexes, for example. Length: 0.12 μm), content is recorded. The prepits provided in the data area D include those having a length equal to or shorter than the optical system resolution limit of the reproduction system 100 (contents are recorded in a random pattern). The same applies to the following.)

  Next, the optical information recording medium 20 having the case 1 structure in which the thin film regions of the first information recording layer and the second information recording layer are in the substantially equal range will be described with reference to FIG. FIG. 2 is a cross-sectional view of the optical information recording medium 20 having the case 1 structure. The optical information recording medium of the present invention is not limited to the two information recording layers, and can have more information recording layers.

  As shown in FIG. 2, the optical information recording medium 20 includes a transparent layer 21 (polycarbonate film: 55 μm, transparent adhesive resin layer: 20 μm) and a first information recording layer 23 (first reproduction layer) in order from the reproduction light incident surface side. Film (zinc oxide: 206 nm) and first light absorption film (Si: 9 nm)), intermediate layer 22 (transparent ultraviolet curable resin: 25 μm), and second information recording layer 24 (second reproduction film (zinc oxide: 180 nm)) The second light absorption film (SUS304: 50 nm)) and the substrate 25 (polyolefin resin substrate) are laminated.

  The first information recording layer 23 has substantially the same radius as the second information recording layer 24, and the lead-in area R provided on the inner periphery of each layer has an optical system resolution limit length. In addition, medium information is recorded by pre-pits (not shown) that are long and concave, for example. Further, a lead-in area R is provided on the inner circumference of each of the first information recording layer 23 and the second information recording layer 24, and a data area D provided on the outer circumference of each lead-in area R includes, for example, The content is recorded by prepits that are concave and convex. The prepits provided in the data area D include those having a length equal to or shorter than the optical system resolution limit of the reproducing apparatus.

  Finally, an optical information recording medium 30 having a case 2 structure in which the thin film region provided in the second information recording layer is wider than the thin film region provided in the first information recording layer is shown in FIG. I will explain. FIG. 3 is a sectional view of the optical information recording medium 30 having the case 2 structure. The optical information recording medium of the present invention is not limited to the two information recording layers, and can have more information recording layers.

  As shown in FIG. 3, the optical information recording medium 30 includes a light-transmitting layer 31 (polycarbonate film: 80 μm, transparent adhesive resin layer: 20 μm) and a first information recording layer 33 (first reproduction layer) in order from the reproduction light incident surface side. Film (zinc oxide: 206 nm) and first light absorption film (Si: 9 nm)), intermediate layer 32 (transparent ultraviolet curable resin: 25 μm), and second information recording layer 34 (second reproduction film (zinc oxide: 180 nm)) The second light absorption film (SUS304: 50 nm)) and the substrate 35 (polyolefin resin substrate) are laminated.

  The second information recording layer 34 is provided from the inner periphery of the first information recording layer 33, and the optical device has in the lead-in area R that is an area expanded from the first information recording layer 33. Medium information is recorded by pre-pits (not shown) made of, for example, concaves and convexes that are longer than the length of the system resolution limit.

  Further, in the data area D of the first information recording layer 33 and the data area D provided on the outer periphery of the lead-in area R of the second information recording layer 304, contents are recorded by, for example, concave and convex prepits. ing. The prepits provided in the data area D include those having a length equal to or shorter than the optical system resolution limit of the reproducing apparatus.

  A reproduction method when reproducing the optical information recording media 10, 20, and 30 having the above-described configurations with the reproduction system 100 (reproduction light wavelength: 405 nm, NA: 0.85) of the present embodiment will be described. To do.

  First, in the reproduction system 100, the optical information recording medium 10 of the present embodiment is reproduced with a reproduction light wavelength for a non-super-resolution optical information recording medium: 405 nm, A. When reproducing at 0.85, as shown in FIG. 1, only one information recording layer is provided on the inner periphery where the lead-in area R is provided. Therefore, the laser light focusing position by the objective lens 102a is irradiated from the initial position facing the lead-in area R in the optical information recording medium 10 while irradiating the reproduction light with power in the single-layer non-super resolution optical information recording medium. (See FIGS. 7A and 7B), the number of times the focus error signal exceeds the predetermined reference voltage + V0 is also one. Therefore, the number of information recording layers of the optical information recording medium 10 is recognized as 1. Next, the condensing position of the laser beam by the objective lens 102a is moved from the drive upper limit position to the initial position while maintaining the reproduction light power in the single-layer non-super resolution optical information recording medium. At that time, the voltage value of the focus error signal detected from the first information recording layer 3 is such that the reflectance RE (17.4%) of the first information recording layer 3 is the reflection of the single-layer non-super-resolution information recording medium. Since it is similar (within range) to the rate RE (12 to 20%), it can be set to an appropriate value by changing the gain of the amplifier included in the focus control circuit 105 or the like. Then, the number of times the focus error signal exceeds the predetermined reference voltage + V0 is counted, and after the first time, the focus servo is turned on when the level first becomes 0 level (center level of focus servo operation). As a result, the focus search process for the first information recording layer 3 is completed. Thereafter, tracking servo is performed by the same method as described above.

  In addition, since the medium information is recorded in the tracked lead-in area R by pre-pits (not shown) made of irregularities longer than the optical system resolution limit length of the reproduction system 100, single-layer non-super resolution optical information recording is performed. The medium information is reproduced with the reproduction light power in the medium.

  As a result, it is recognized that the optical information recording medium 10 of the present embodiment is a two-layer super-resolution optical information recording medium.

  Therefore, it is possible to satisfactorily reproduce the data area D with the reproducing light power corresponding to the double-layer super-resolution optical information recording medium.

  In the present application, as described above, when the reflectance RE of the first information recording layer 3 is within the standard range of the reflectance RE of the single-layer non-super resolution optical information recording medium, the reflectance RE of the first information recording layer 3 The reflectance RE of the single-layer non-super resolution optical information recording medium is called equal.

  Next, the optical information recording medium 20 having the structure of Case 1 in which the thin film areas of the first information recording layer and the second information recording layer are substantially equal is used in the reproduction system 100 for the non-super-resolution optical information recording medium. Reproduction light wavelength: 405 nm, N.I. A. : A case of reproduction at 0.85 will be described.

  In the optical information recording medium 20, as shown in FIG. 2, two information recording layers are provided on the inner periphery where the lead-in area R is provided. Therefore, when reproducing the optical information recording medium 20 at the reproduction light wavelength for the non-super resolution optical information recording medium, the laser by the objective lens 102a while irradiating the reproduction light with the power in the single layer non-super resolution optical information recording medium. When the light condensing position is moved from the initial position facing the lead-in area R in the optical information recording medium 20 to the driving upper limit position, the number of times that the focus error signal exceeds the predetermined reference voltage + V0 is also twice. .

  Therefore, the number of information recording layers of the optical information recording medium 20 is recognized as 2. However, it cannot be determined as a super-resolution optical information recording medium. Thereafter, the focus search is performed in the same manner as described above. However, since there are two information recording layers, the focus search is performed on one of the information recording layers. However, the standard defining the optical information recording medium 20 has no restriction on the reproduction system 100. For this reason, the information recording layer of the first information recording layer 23 and the second information recording layer 24 is subjected to the focus search depending on the reproduction system 100. In addition, for a newly standardized optical information recording medium, the reproduction system 100 may be initially focus-searched on any one of the first information recording layer 23 and the second information recording layer 24. There is a need.

  Therefore, for example, in the case of a two-layer optical information recording medium, a case will be described in which the reproduction system 100 that performs reproduction is a reproduction system in which the second information recording layer 204 is first focus-searched.

  After the reproduction light is changed to the reproduction light power corresponding to the two-layer non-super resolution optical information recording medium, the condensing position of the laser light by the objective lens 102a is moved from the drive upper limit position to the initial position. At that time, since the voltage value of the focus error signal detected from the second information recording layer 24 becomes very low, the gain of the amplifier included in the focus control circuit 105 or the like is changed without increasing the reproduction light power. However, it may not be possible to obtain an appropriate value.

  The reason why the voltage value of the focus error signal is very low will be described below.

  In the case of not only the optical information recording medium 20 having the case 1 structure but also in the two-layer super-resolution optical information recording medium, the transmittance of the first information recording layer is the transmittance of the first information recording layer in the two-layer non-super-resolution optical information recording medium. Many of them are lower. Unlike the first information recording layer of the two-layer non-super-resolution optical information recording medium that can be reproduced simply by reflection, in order to reproduce the first information recording layer in the two-layer super-resolution optical information recording medium, This is because it is necessary to perform super-resolution reproduction using the generated heat. Therefore, since the reproduction light irradiated on the second information recording layer passes through the first information recording layer both on the way and on the return side, the reproduction light returns, so that it corresponds to a two-layer non-super resolution optical information recording medium. This is because the amount of return light from the second information recording layer becomes very small with the reproduced light power.

  Therefore, the number of times that the focus error signal exceeds the predetermined reference voltage + V0 is counted, and after the second time, the focus servo is turned on when it first becomes 0 level (center level of focus servo operation). It may not be possible to do so. In this case, naturally, since the focus search process does not end, the information in the lead-in area R is not reproduced, and it is not recognized that the optical information recording medium 20 is a two-layer super-resolution optical information recording medium.

  Finally, in the reproduction system 100, the optical information recording medium 30 having the case 2 structure in which the area of the thin film provided in the second information recording layer is wider than the area of the thin film provided in the first information recording layer. A case where reproduction is performed at a reproduction light wavelength for a super-resolution optical information recording medium will be described.

  As shown in FIG. 3, in the optical information recording medium 30, only one information recording layer is provided on the inner periphery where the lead-in area R is provided. Therefore, when the optical information recording medium 30 is reproduced at the reproducing light wavelength for the non-super-resolution optical information recording medium in the reproducing system 100, the single layer non-layer is formed from the initial position facing the lead-in area R in the optical information recording medium 30. When the objective lens 102a is moved to the drive upper limit position while irradiating the reproduction light with power in the super-resolution optical information recording medium, the number of times that the focus error signal exceeds the predetermined reference voltage + V0 is once. Therefore, the number of information recording layers of the optical information recording medium 30 is recognized as 1.

  Therefore, when reproducing the optical information recording medium 30, the objective lens 102a is moved from the drive upper limit position to the initial position while maintaining the reproduction light power of the single-layer non-super resolution optical information recording medium. At this time, since the voltage value of the focus error signal detected from the second information recording layer 34 is very high, an appropriate value can be obtained even if the gain of the amplifier included in the focus control circuit 105 is changed. It may not be possible.

  The reason why the voltage value of the focus error signal is very high will be described below.

  As described above, in the two-layer super-resolution optical information recording medium, the transmittance of the first information recording layer is often lower than the transmittance of the first information recording layer in the two-layer non-super-resolution optical information recording medium. Therefore, the reflectance of the second information recording layer itself in the two-layer super-resolution optical information recording medium needs to be very high. This is to obtain sufficient return light when the reproduction light is irradiated through the first information recording layer with the power corresponding to the two-layer super-resolution optical information recording medium.

  Therefore, when reproduction light is irradiated to the second information recording layer in an area where the first information recording layer does not exist, the amount of return light never passes through the first information recording layer, and the second information recording layer This is because the reflectance itself is so high that it becomes very large.

  Therefore, the number of times that the focus error signal exceeds the predetermined reference voltage + V0 is counted, and after the second time, the focus servo is turned on when it first becomes 0 level (center level of focus servo operation). It may not be possible to do so. In this case, the focus search process does not end, so the information in the lead-in area R is not reproduced, and the optical information recording medium 30 is not recognized as a two-layer super-resolution optical information recording medium.

  As described above, the optical information recording medium 10 according to the present embodiment can reliably focus in the lead-in area R as compared with the optical information recording medium 20 and the optical information recording medium 30, and thus can be reproduced. Even if the system 100 is not provided with new medium identification means, the medium information of the lead-in area R, which is information necessary for reproduction, can be reproduced. Accordingly, since the optical information recording medium can be specified, the reproduction failure at the start of reproduction of the optical information recording medium in which the super-resolution optical information recording medium is included in the variation is solved, and the reliability of the reproduction of the recorded information in the data area D is improved.

  Also, since the optical information recording medium 10 is provided with a film capable of super-resolution reproduction, content recorded in the data area D can be reproduced at a higher density than the non-super-resolution optical information recording medium. . For this reason, the substantial recording density is improved.

  In the optical information recording medium 10, the optical information recording medium information is recorded in the lead-in area R with prepits having irregularities longer than the length of the optical system resolution limit of the reproducing apparatus. This is because, for example, when there is no information in the lead-in area R and the standard is set so that the optical information recording medium can be specified, the optical information recording medium information itself is not necessary.

  Further, it may not be a so-called read-only optical information recording medium in which content is recorded in the data area D by prepits, and may be a recordable optical information recording medium capable of recording content. For example, a multi-layer recording type having two or more information recording layers on which content is recorded by forming a recording mark having a length shorter than the optical system resolution limit length of the reproducing apparatus on the thin film. It may be an optical information recording medium.

  In that case, in addition to the above effects, it is possible to record content in the data area D at a higher density than the non-super-resolution optical information recording medium.

  Furthermore, the thin film provided in the information recording layer may not be zinc oxide, silicon (Si), SUS304, or the like. If the thin film enables super-resolution reproduction, a single layer or two or more layers may be used. A multilayer film may be used.

  Further, the area of the first information recording layer 3 that is expanded more than the second information recording layer 4 may not be on the inner peripheral side. However, since it differs from the position of the general lead-in area R, it may be difficult to share with other optical information recording media. In addition, in an optical information recording medium, since a thin film to be an information recording layer is generally formed by sputtering or the like, the thin film of each information recording layer is often laminated within the same range for cost reduction. In addition, it is possible to provide an information recording layer without a thin film in the middle part by forming a film twice using a mask that covers inner and outer circumferences of different diameters at the time of film formation. Costs up. Of course, when different film types are provided on the same surface, the cost increases. Therefore, the area of the first information recording layer 3 that is expanded more than the second information recording layer 4 is on the inner peripheral side, so that the cost can be reduced.

  In addition, the reproduction information of each layer may be recorded in the lead-in area R of the first information recording layer 3 by prepits composed of concave and / or convex longer than the optical system resolution limit length of the reproducing apparatus. In that case, the reproduction system 100 is newly provided with a function of reproducing each information recording layer in accordance with the reproduction information of each information recording layer recorded in the lead-in area R of the first information recording layer. By using, reproduction can be started under optimum conditions in each information recording layer. As a result, it is not necessary to adjust the reproduction light power for each layer, and the time until reproduction in each information recording layer can be shortened.

  Further, depending on the standard, or when substantially all the driving devices perform a focus search from the first information recording layer 3, the extended area of the first information recording layer 3 is not necessary. However, even in such a case, recording the medium information and the reproduction information in the lead-in area R allows the reproduction to be started under the optimum conditions in each information recording layer, and the reproduction optical power for each layer. Adjustment is unnecessary, and the time until reproduction in each information recording layer can be shortened.

  In that case, also in the optical information recording media 20 and 30, by recording the medium information and the reproduction information in the lead-in area R, the reproduction can be started under the optimum conditions in each information recording layer.

  Note that the reproduction information refers to reproduction information for setting reproduction conditions according to variations such as ROM, RW, RE, or RAM for reproducing contents recorded in each information recording layer.

  The optical information recording media 10, 20, and 30 are CD-ROM (Compact Disk Read Only Memory), CD-R (Compact Disk Recordable), CD-RW (Compact Disk Rewritable), DVD-ROM (Digital Versatile Disk). Optical read discs such as Read Only Memory (DVD), DVD-RW (Digital Versatile Disk Rewritable), BD (Blue-ray Disc), BD (Blue-ray Disc) -ROM, magneto-optical disc, phase change disc, etc. The optical information recording medium can be applied to various optical discs. The present invention does not ask the recording method or size.

  As described above, in the optical information recording medium 20 that is the multilayer super-resolution optical information recording medium of the present embodiment, the first information recording layer 3 has the optical system resolution limit included in the reproducing device for the non-super-resolution optical information recording medium. An optical system solution having a reflectance equal to that of a single-layer read-only optical information recording medium having only prepits for a non-super-resolution optical information recording medium that is longer than the length of the recording medium or a reproducing apparatus for a non-super-resolution optical information recording medium. It has a reflectance equal to that of a single-layer recording type optical information recording medium in which information is recorded only by a recording mark longer than the image limit length.

  For this reason, even if it is a multilayer super-resolution optical information recording medium, if it is the reproduction system 100 that can reproduce the single-layer non-super-resolution optical information recording medium, the first information recording layer 3 can be focused. It is possible to identify whether the optical information recording medium 20 set in the reproduction system 100 is a non-super-resolution optical information recording medium or a super-resolution optical information recording medium. For example, if the pre-pit is less than the resolution limit, it cannot be reproduced and can be identified as a super-resolution medium.

  In the present embodiment, the first information recording layer 3 has a lead-in area R that is a wider area than the thin film of the other second information recording layer 4. Therefore, in this lead-in area R, it is possible to record medium information indicating whether the optical information recording medium 20 is a non-super-resolution optical information recording medium or a super-resolution optical information recording medium.

  Therefore, the optical information recording medium 10 that can easily identify the type of the super-resolution optical information recording medium or the non-super-resolution optical information recording medium in the multilayer reproduction-only or multilayer recording type optical information recording medium 10. Can be provided.

  In the optical information recording medium 10 of the present embodiment, the lead-in area R that is a wider area than the second information recording layer 4 and the like in the first information recording layer 3 indicates the type of the optical information recording medium. It is preferable that the medium information is recorded with only prepits longer than the length of the optical system resolution limit of the reproducing apparatus.

  As a result, even with a multilayer super-resolution optical information recording medium, if the reproduction system 100 can reproduce a single-layer non-super-resolution optical information recording medium, the lead-in area R in the first information recording layer 3 can be focused. It is possible to identify the type of the optical information recording medium whether it is a super-resolution optical information recording medium. If the type of optical information recording medium can be identified, the number of layers can be determined by detecting the S-characteristic of the focus error signal indicating the presence of the information recording layer.

  Further, in the optical information recording medium 20 of the present embodiment, the first information recording layer 3 has reproduction information for reproducing the content recorded on each information recording layer, and the optical system resolution limit of the reproduction apparatus. It is preferable that recording is performed with only pre-pits longer than the length of.

  As a result, the reproduction information for reproducing the content recorded in each information recording layer in either the lead-in area R or the data area D in the first information recording layer 3 is only a pre-pit for the non-super-resolution optical information recording medium. Therefore, even if it is a multi-layer super-resolution optical information recording medium, if the reproduction system 100 can reproduce a single-layer non-super-resolution optical information recording medium, the first information recording layer 3 can be focused. At that time, reproduction information for reproducing the content recorded in each information recording layer can be reproduced. As a result, reproduction can be started under optimum reproduction conditions in each information recording layer, and reproduction light power adjustment in each information recording layer becomes unnecessary, and the time until reproduction in each information recording layer can be shortened.

  In the optical information recording medium 20 according to the present embodiment, the reproduction apparatus has reproduction information for reproducing the content recorded in each information recording layer in the lead-in area R in the first information recording layer 3. It is preferable to record only prepits longer than the length of the optical system resolution limit.

  Thereby, in the lead-in area R in the first information recording layer 3, since the reproduction information for reproducing the content recorded in each information recording layer is recorded only with the pre-pits for the non-super-resolution optical information recording medium, Even if it is a multilayer super-resolution optical information recording medium, the first information recording layer 3 can be focused as long as the reproducing system 100 can reproduce the single-layer non-super-resolution optical information recording medium. It is possible to reproduce the reproduction information for reproducing the content recorded in. As a result, reproduction can be started under optimum reproduction conditions in each information recording layer, and reproduction light power adjustment in each information recording layer becomes unnecessary, and the time until reproduction in each information recording layer can be shortened.

  Further, in the optical information recording media 10, 20, and 30 of the present embodiment, in the multi-layer super-resolution optical information recording medium, the first information recording layers 3, 23, and 33 are longer than the length of the optical system resolution limit of the reproducing apparatus. A non-super-resolution optical information recording medium having a reflectance equal to that of a single-layer reproduction-only optical information recording medium having only prepits for a long non-super-resolution optical information recording medium or longer than the optical system resolution limit length of the reproducing apparatus It has a reflectance equal to that of a single-layer recording type optical information recording medium in which information is recorded using only recording marks for the medium.

  For this reason, even if it is a multi-layer super-resolution optical information recording medium, if the reproducing apparatus can reproduce the single-layer non-super-resolution optical information recording medium, the first information recording layer can be focused and its contents can be read. it can.

  In the present embodiment, the first information recording layers 3, 23, and 33 reproduce the medium information indicating the types of the optical information recording media 10, 20, and 30 and the content recorded in each information recording layer. It is possible that the reproduction information for recording is recorded only with prepits longer than the length of the optical system resolution limit of the reproduction apparatus.

  For this reason, even if it is a multilayer super-resolution optical information recording medium according to the medium information indicating the type of optical information recording medium recorded with the pre-pits for the non-super-resolution optical information recording medium in the first information recording layers 3, 23, 33, If the reproducing apparatus can reproduce the single-layer non-super-resolution optical information recording medium, the first information recording layer can be focused, and the contents are read and the optical information recording medium set in the reproducing system 100 is non-super. It is possible to identify the type of the resolution optical information recording medium or the super resolution optical information recording medium.

  In addition, the multi-layer super-resolution optical information recording is performed according to the reproduction information for reproducing the content recorded in each information recording layer, which is recorded in the first information recording layers 3, 23, and 33 with the prepits for the non-super-resolution optical information recording medium. Even if it is a medium, the reproduction system 100 capable of reproducing a single-layer non-super-resolution optical information recording medium can focus on the first information recording layers 3, 23, and 33. Reproduction information for reproducing the recorded content can be reproduced. As a result, reproduction can be started under optimum reproduction conditions in each information recording layer, and reproduction light power adjustment in each information recording layer becomes unnecessary, and the time until reproduction in each information recording layer can be shortened.

  Therefore, the optical information recording medium 10/20 that can easily identify the type of the super-resolution optical information recording medium or the non-super-resolution optical information recording medium in the multilayer reproduction-only or multilayer recording type optical information recording medium. 30 can be provided.

  In addition, the reproduction system 100 according to the present embodiment performs reproduction using reproduction information of other information recording layers recorded in the first information recording layers 3, 23, and 33. Accordingly, it is possible to provide the reproducing system 100 that can easily identify the type of the super-resolution optical information recording medium or the non-super-resolution optical information recording medium.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Such embodiments are also included in the technical scope of the present invention.

  The present invention can be applied to various kinds of optically readable discs such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RW, BD, BD-ROM, magneto-optical disc, phase change disc, etc. The present invention can be applied to an optical information recording medium and an optical information recording medium driving device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an embodiment of an optical information recording medium according to the present invention, with a main part of a super-resolution optical information recording medium broken away. FIG. 10 is a perspective view showing another configuration of the optical information recording medium, with a main part of the super-resolution optical information recording medium broken away. FIG. 10 is a perspective view showing still another configuration of the optical information recording medium, with a main part of the super-resolution optical information recording medium broken away. It is sectional drawing which shows the detailed structure of the said super-resolution optical information recording medium. It is a block diagram which shows the structure of the reproduction | regeneration system which reproduces | regenerates the said optical information recording medium. It is a wave form diagram which shows the focus error signal waveform at the time of the focus search in the reproduction | regeneration system when reproducing | regenerating the said super-resolution optical information recording medium. (A) is a timing chart which shows the condensing position of the objective lens in the case of performing a layer jump from the first information recording layer to the fourth information recording layer, and (b) is a super-resolution optical information recording medium corresponding to (a) FIG. 6 is a waveform diagram showing a focus error signal waveform at the time of focus search in the playback system when playing back. It is a follow chart which shows operation | movement of the said reproduction | regeneration system. (A) and (b) are the perspective views which fracture | rupture and show the principal part of the conventional super-resolution optical information recording medium.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light transmission layer 2 Intermediate | middle layer 3 1st information recording layer (information recording layer)
3a First reproduction film 3b First light absorption film 4 Second information recording layer (information recording layer)
4a Second reproduction film 4b Second light absorption film 5 Substrate 10 Optical information recording medium 20 Optical information recording medium 23 First information recording layer (information recording layer)
24 Second information recording layer (information recording layer)
25 substrate 30 optical information recording medium 33 first information recording layer (information recording layer)
34 Second information recording layer (information recording layer)
35 Substrate 100 Playback System (Optical Information Recording Medium Drive Device)
102a Objective lens 105 Focus control circuit 106 Tracking control circuit 107 Phase difference detection circuit D Data area R Lead-in area

Claims (7)

Information is recorded by prepits consisting of at least one of concave and convex, and there are two or more information recording layers in which one or more thin films are laminated on the prepits, and each information recording layer has a reproducing device. An optical information recording medium dedicated to multilayer reproduction having the pre-pit having a length that includes a length shorter than the length of the optical system resolution limit,
The first information recording layer closest to the reproduction light incident surface has a reflectance equal to that of a single layer reproduction-dedicated optical information recording medium having only a prepit longer than the optical system resolution limit length of the reproduction apparatus, or is reproduced. The apparatus has a reflectance equal to that of a single-layer recording type optical information recording medium in which information is recorded only by a recording mark longer than the length of the optical system resolution limit of the apparatus, and
The optical information recording medium, wherein the first information recording layer further has a wider area than a thin film of another information recording layer different from the first information recording layer. Multi-layer recording type optical information having two or more information recording layers on which content is recorded by forming a recording mark having a length shorter than the optical system resolution limit length of the reproducing apparatus on the thin film A recording medium,
The first information recording layer closest to the reproduction light incident surface is equal to a single-layer reproduction-dedicated optical information recording medium having only a prepit consisting of at least one of a concave and a convex longer than the optical system resolution limit length of the reproduction apparatus. While having a reflectance, or having a reflectance equal to that of a single-layer recording type optical information recording medium in which content is recorded only by a recording mark longer than the length of the optical system resolution limit of the reproducing apparatus,
The optical information recording medium, wherein the first information recording layer further has a wider area than a thin film of another information recording layer different from the first information recording layer.   3. The first information recording layer according to claim 1, wherein the first information recording layer has a wider area on the inner peripheral side than a thin film of another information recording layer different from the first information recording layer. Optical information recording medium.   In the first information recording layer, in a wider area than the thin film of another information recording layer different from the first information recording layer, medium information indicating the type of the optical information recording medium is provided in the optical system of the reproducing apparatus. 4. The optical information recording medium according to claim 1, wherein the optical information recording medium is recorded only with a prepit longer than a resolution limit length.   In the first information recording layer, reproduction information for reproducing the content recorded in each information recording layer is recorded only with prepits longer than the optical system resolution limit length of the reproduction apparatus. The optical information recording medium according to claim 1, wherein the optical information recording medium is a recording medium.   In the first information recording layer, in a wider area than the thin film of the other information recording layer different from the first information recording layer, reproduction information for reproducing the content recorded in each information recording layer, The optical information recording medium according to any one of claims 1 to 4, wherein the optical information recording medium is recorded only with prepits longer than a length of an optical system resolution limit of the reproducing apparatus. An optical information recording medium driving device for reproducing the optical information recording medium according to claim 1,
An optical information recording medium driving apparatus for performing reproduction using reproduction information of each of the other information recording layers recorded on the first information recording layer.

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