Source: http://www.google.com/patents/US20020136122?dq=7800613
Timestamp: 2016-05-29 09:44:23
Document Index: 315601018

Matched Legal Cases: ['art. 4', 'art 12', 'art 12', 'art 12', 'art 12', 'arts 37', 'arts 38', 'arts 38']

Patent US20020136122 - Optical information record medium, method of recording information on ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsIn recording on a second or deeper information recording layer of an optical information record medium having a plurality of recording layers, power of a recording laser beam is appropriately controlled even when quantity of transmitting beam is changed depending on recording states of information recording...http://www.google.com/patents/US20020136122?utm_source=gb-gplus-sharePatent US20020136122 - Optical information record medium, method of recording information on optical information record medium, and information recording apparatusAdvanced Patent SearchPublication numberUS20020136122 A1Publication typeApplicationApplication numberUS 10/100,022Publication dateSep 26, 2002Filing dateMar 19, 2002Priority dateMar 21, 2001Also published asEP1244096A2, EP1244096A3Publication number100022, 10100022, US 2002/0136122 A1, US 2002/136122 A1, US 20020136122 A1, US 20020136122A1, US 2002136122 A1, US 2002136122A1, US-A1-20020136122, US-A1-2002136122, US2002/0136122A1, US2002/136122A1, US20020136122 A1, US20020136122A1, US2002136122 A1, US2002136122A1InventorsKazuhiko NakanoOriginal AssigneeKazuhiko NakanoExport CitationBiBTeX, EndNote, RefManPatent Citations (2), Referenced by (152), Classifications (18), Legal Events (1) External Links: USPTO, USPTO Assignment, EspacenetOptical information record medium, method of recording information on optical information record medium, and information recording apparatus
US 20020136122 A1Abstract
In recording on a second or deeper information recording layer of an optical information record medium having a plurality of recording layers, power of a recording laser beam is appropriately controlled even when quantity of transmitting beam is changed depending on recording states of information recording layers positioned on the incidence side of the information recording layer in which information is to be recorded. The optical information record medium is provided with recording power test areas respectively in the second and deeper information recording layers, separately from user data recording areas. Those recording power test areas are used for testing a recording power of the recording laser beam. Further, before recording on a user data recording area in a second or deeper information recording layer, the recording power test area in the recording layer in question is used to test the recording power, to obtain a reference power and a level of a return beam at that time. Then, in recording on an arbitrary location in the user data area of the recording layer in question, the optimum recording power for the mentioned arbitrary location is calculated using a level of a return beam detected in recording on a location in the neighborhood of the mentioned arbitrary location, the reference power obtained in the test of the recording power, and the level of the return beam obtained at that time. The power of the recording laser beam is controlled such that recording on the mentioned arbitrary location is performed with that optimum recording power. Images(7) Claims(9)
What is claimed is: 1. An optical information record medium having two or more information recording layers, wherein: said optical information record medium has recording power test areas respectively in second and deeper information recording layers from a recording laser beam incidence side, said recording power test areas being different from user data recording areas and used for testing a recording power. 2. The optical information record medium according to claim 1, wherein: said recording power test areas provided respectively in the second and deeper information recording layers are located not to overlap each other seen from the laser beam incidence side. 3. The optical information record medium according to claim 1, wherein: in each information recording layer positioned on the recording laser beam incidence side of an information recording layer provided with said recording power test area, said each information recording layer is provided with a part in a state of a lowest transmittance or a highest transmittance and a recording laser beam for irradiating said recording power test area is transmitted through said part. 4. The optical information record medium according to claim 3, wherein: each of said second and deeper information recording layers is provided with both said recording power test area in the state of the lowest transmittance and said recording power test area in the state of the highest transmittance. 5. An information recording method in which a recording laser beam is used for recording information on an optical information record medium having two or more information recording layers, wherein: said optical information record medium has recording power test areas respectively in second and deeper information recording layers from a recording laser beam incidence side, said recording power test areas being different from user data recording areas and used for testing a recording power; and said information recording method comprises steps of: testing the recording power using a recording power test area in a second or deeper information recording layer before recording on a user data recording area of said information recording layer, to obtain a reference power and a level of a return beam at that time; calculating an optimum recording power for an arbitrary location in the user data recording area of said information recording layer before recording on said arbitrary location, with said optimum recording power being calculated using a recording power used for recording on a location in neighborhood of said arbitrary location, a level of a return beam detected at that time, the reference power obtained in said step of testing the recording power, and the level of the return beam obtained at that time; and controlling the recording power such that recording on said arbitrary location is performed with said optimum recording power. 6. The information recording method according to claim 5, wherein: the recording power is controlled such that the optimum recording power Popt for said arbitrary location satisfies following expressions: P opt =P 0�(I E /I' B)0.5 I' B =I B�(P B /P 0)2 in which P0 is the reference power obtained in said step of testing the recording power, IE is the level of the return beam obtained at that time, PB is the recording power used for recording on the location in the neighborhood of said arbitrary location, and IB is the level of the return beam detected at that time. 7. The information recording method according to claim 5, wherein: in each information recording layer positioned on a recording laser beam incidence side of the information recording layer provided with said arbitrary location and said location in the neighborhood, a positional deviation between a part through which the recording laser beam irradiated for recording on said arbitrary location is transmitted and a part through which the recording laser beam irradiated for recording on said location in the neighborhood is within a predetermined range. 8. An information recording apparatus using a recording laser beam for recording information on an optical information record medium that has two or more information recording layers and recording power test areas provided respectively in second and deeper information recording layers from a recording laser beam incidence side, with said recording power test areas being different from user data recording areas and used for testing a recording power of the recording laser beam, wherein: said information recording apparatus comprises: a laser source; an irradiation means that irradiates a recording laser beam from said laser source onto the optical information record medium; a photo detection means for detecting a return beam of said recording laser beam; and a control unit; and said control unit: tests the recording power using a recording power test area in a second or deeper information recording layer before recording on a user data recording area of said information recording layer, to obtain a reference power and a level of a return beam at that time; calculates an optimum recording power for an arbitrary location in the user data recording area of said information recording layer before recording on said arbitrary location, with said optimum recording power being calculated using a recording power used for recording on a location in neighborhood of said arbitrary location, a level of a return beam detected at that time, the reference power obtained in said step of testing the recording power, and the level of the return beam obtained at that time; and controls the recording power such that recording on said arbitrary location is performed with said optimum recording power. 9. The information recording apparatus according to claim 8, wherein: said control unit controls the recording power such that the optimum recording power Popt for said arbitrary location satisfies following expressions: P opt =P 0�(I E /I' B)0.5 I' B =I B�(P B /P 0)2 in which P0 is the reference power obtained in said step of testing the recording power, IE is the level of the return beam obtained at that time, PB is the recording power used for recording on the location in the neighborhood of said arbitrary location, and IB is the level of the return beam detected at that time. Description
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an optical information record medium provided with a plurality of information recording layers, and a method of recording information to this optical information record medium. [0003] 2. Related Art Statement [0004] Recently, practical use of a mass storage and high density optical information disk is advancing. As a reproduction-only medium, mainly a compact disk (CD), a laser disk (LD), and the like are widely spread. Further, as a record and reproduction disk, a phase change type disk utilizing reflectance change between amorphous and crystal states, a magneto-optical disk (MO) utilizing thermomagnetic recording and magneto-optic effects, and the like are being established as external storage media for a computer. Further, CD-R, which can record only once and can be played back on a CD drive or a CD-ROM drive, is being established as an experimental disk in an authoring stage or as a master disk. [0005] Further, as a next-generation multimedia medium, is proposed an optical disk that covers audio data usually recorded in a CD, high quality video data usually recorded in an LD, and computer data usually recorded in a CD-ROM, and integrates a reproduction-only disk and a record medium. This type of medium was standardized as DVD (Digital Versatile Disk) by a working group (DVD consortium) in August 1996. [0006] DVD employs some new techniques in order to store a digital video signal and mass data for computer, namely, in order to increase a recording density of a disk more than the conventional ones. A size of a pit in DVD is a little smaller than a half, both in the radial and circumferential directions, in comparison with CD. Further, in order to remove effect of deterioration in reproduction owing to a tilt of a disk, thickness of its substrate is determined to be 0.6 mm. And, to secure mechanical strength, a DVD is structured such that two substrate of 0.6 mm are stuck together. Information may be recorded on one or both of the substrate that have been stuck, and disk structure may be single-side reproduction, double-side reproduction, or single-sided two layers, double-sided two layers. Even in the case of a single-sided single layer disk, its recording density is six times the recording density of a CD. Or, in other words, it can record two hours' moving image having quality equivalent or superior to the laser disk. [0007] Further, phase change disks such as DVD-RAM and DVD-RW are coming into wide use. In these disks, an end user himself can record, reproduce and erase information. For example, mass information such as a digital moving image can be treated using such a phase change disk, and, if necessary, random access is possible to record and reproduce the information. Thus, it is expected that a phase change disk is used for a home vide recorder that will replace VCR (Video Cassette Recorder) of the present mainstream. [0008] In order that such DVD-RAM, DVD-RW etc. substitute videotape, it is desired to make them have a higher density and larger capacity. Capacity of the current DVD is 4.7 GB for one side, and can record about two hours' NTSC moving image. However, when it is considered as a substitute of videotape, recording time of 4-6 hours or more is required. Further, in order to record high-definition digital moving image of two or more hours, recording capacity of 15-30 GB is required. [0009] As a method of increasing recording capacity of an optical disk, may be mentioned a method in which a plurality of information recording layers are used, in addition to a method in which laser of a shorter wave length is used to increase a recording density, and a method in which an object lens having larger NA (numerical aperture) is used to increase a recording density. With respect to the current DVD, a working group proposes a multi-layer disk such as DVD-9 and DVD-18, in which information can be reproduced from two information recording layers on one side. Such a disk realizes larger recording capacity in comparison with a single layer disk. SUMMARY OF THE INVENTION [0010] In the case of a plurality of information recording layers that can record information, the following problems exist. For example, in the case of a two-layer disk in which record and reproduction can be performed from one side, information can be recorded in a way similar to the conventional single layer disk when the information is recorded on a first information recording layer closer to the laser beam incidence side. When, however, information is recorded on a second information recording layer, laser beam that has been transmitted through the first information recording layer is used to record the information on the second information recording layer, and accordingly, the recording into the second information recording layer is affected by the transmittance of the first information recording layer. The transmittance of the first information recording layer changes depending on its state (erased state/recorded state), and as a result, quantity of beam reaching the second information recording layer changes depending on the sate of the first information recording layer. [0011] [0011]FIG. 9 is a diagram for explaining the case where information is recorded on an optical information record medium having two information recording layers. In the figure, a reference numeral 21 refers to an optical information record medium, 22 to a substrate, 23 to a first information recording layer, 24 to an intermediate layer, 25 to a second information recording layer, 26 to a recording laser beam, and 27 to a spot. [0012] The first information recording layer 23 is formed on one side of the substrate 22 of the optical information record medium 21. The first information recording layer 23 is made of a phase change material (for example, a GeTeSb (germanium-tellurium-antimony family material)), whose crystal state (higher reflectance and lower transmittance) defines an erased state and amorphous state (lower reflectance and higher transmittance) defines a recorded state for example. On the first information recording layer 23, is formed the second information recording layer 25 via the intermediate layer (for example, an ultraviolet curing resin layer) 24. The second information recording layer 25 is made of a phase change material (for example, a GeTeSb family material), which defines an erased state by its crystal state and a recorded state by its amorphous state similarly to the first information recording layer 23, for example. When information is recorded on the first information recording layer 23 and second information recording layer 25 of such an optical information record medium 21, areas of record marks become an amorphous state and areas other than the record marks become a crystal state. In other words, in the first information recording layer 23 and second information recording layer 25, areas where no information is recorded have the lower transmittance since they are in the crystal state, and areas where information is recorded have the higher transmittance than the areas where no information is recorded, since recording marks in the amorphous state are formed there. [0013] Thus, in a phase change disk such as DVD-RAM, usually an erased area is in a crystal state and a recorded area is in an amorphous state, and recording and reproduction are realized by a change in its optical constant, i.e., a change in the reflectance. When the first information recording layer 23 is in the unrecorded state (i.e., the crystal state), its transmittance is low, and quantity of recording laser beam reaching the second information recording layer 25 becomes smaller. On the contrary, when the first information recording layer 23 is in the recorded state (i.e., the amorphous state), its transmittance is high, and quantity of recording laser beam reaching the second information recording layer 25 becomes larger. When recording power is adjusted to either state, deviation from the desired recording power is caused depending on the recorded or unrecorded state of the first information recording layer 23. Fluctuation in the recording power causes deterioration of recording characteristics such as jitter and error rate properties of the second information recording layer 25. [0014] Here, referring to FIG. 9, recording power in the second information recording layer 25 will be described. When information is to be recorded on the second information recording layer 25 of an optical information record medium 21, a recording laser beam 26, whose recording power is modulated according to the information to be recorded, is irradiated onto the second information recording layer 25 via a substrate 22. The recording laser beam 26 is controlled to focus on the second information recording layer 25. At that time, the recording laser beam 26 is transmitted through the first information recording layer 23 to reach the second information recording layer 25. Accordingly, the quantity of the recording laser beam 26 reaching the second information recording layer 25 changes depending on the state of the first information recording layer 23 at a part (a spot 27) on which the recording laser beam 26 is irradiated. [0015] [0015]FIG. 10 is a diagram for explaining states of the area (spot 27) in the first information recording layer 23, on which the recording laser beam 26 is irradiated, when the recording laser beam 26 is used to record information on the second information recording layer 25. There are three cases with respect to the state of this spotted area 27, i.e., a case (A) where all the area is in the erased state, a case (B) where a part of the area is in the erased state and the other part is in the recorded state, and a case (C) where all the area is in the recorded state. Here, however, in the case (B) where a part of the area is in the erased state and the other part is in the recorded state, the ratio between the erased area and the recorded area is not constant, and changes depending on the recorded state. [0016] Assuming that T1 is the transmittance in the case (A), T2 (T2 varies according to the ratio between the erased area and the recorded area) in the case (B), and T3 in the case (C), then, T1<T2<T3. [0017] A multi-layer optical disk described in Japanese Unexamined Patent Laid-Open No. 11-195243 copes with this problem by limiting a film thickness of each layer or optical absorption coefficient to lessen decay of the recording laser beam due to the first information recording layer. However, it is impossible to have the same transmittance between a recorded area and an erased area of the first information recording layer. Thus, it is inevitable that recording of information on the second information recording layer is affected by a state of the first information recording layer. [0018] This will be described taking an example. It is assumed that the transmittance TE of the first information recording layer 23 of the optical information record medium 21 shown in FIG. 9 is 10% when all the area irradiated by the recording laser beam 26 is in the erased state (i.e., the crystal state), and that the transmittance TR is 40% when all the area irradiated by the recording laser beam 26 is in the recorded state (i.e., the amorphous state at a record mark area). Here, it is assumed that the optimum recording power P0 for the second information recording layer 25 is 1 mW when the first information recording layer 23 is in the erased state (the state in which the transmittance is lowest). Then, it is required that the recording power of the recording laser beam 26 is 10 mW (10 mW�0.1=1 mW, since the transmittance of the first information recording layer 23 is 10%). On the other hand, when the power of the recording laser beam 26 is 10 mW and all the area irradiated by the recording laser beam 26 in the first information recording layer 23 is in the recorded state (the state in which the transmission is highest), then, the recording power reaching the second information recording layer 23 becomes 4 mW (10 mW�0.4=4 mW), which is over power. [0019] Here, the recording power of the recording laser beam 26 can be controlled if it is possible to know previously the transmittance TR for the case where the first information recording layer 23 is in the recorded state. However, as described referring to FIG. 10, the transmittance of an area within a spot 27 of the recording laser beam 26 changes depending on the ratio of the recorded area to the erased area. Thus, the transmittance TR of the first information recording layer 23 can not be known in advance. [0020] The present invention has been made taking the above situation into consideration. An object of the present invention is to control suitably the power of the recording laser beam when information is recorded on a second or deeper information recording layer in an optical information record medium having two or more information recording layers, even if quantity of transmitted beam is changed depending on a recording state of a recording layer positioned on the incidence side of the information recording layer on which the information is to be recorded. [0021] To solve the above-described problems, the present invention provides an optical information record medium having two or more information recording layers, wherein: said optical information record medium has recording power test areas respectively in second and deeper information recording layers from a recording laser beam incidence side, said recording power test areas being different from user data recording areas and used for testing a recording power. Here, it is favorable that the recording power test areas are located not to overlap each other seen from the laser beam incidence side. [0022] Further, in an information recording method of the present invention, information is recorded on the optical information record medium having the above-described configuration, using a recording laser beam. Before recording on a user data recording area in a second or deeper information recording layer, the recording power test area in the recording layer in question is used to test the recording power, to obtain a reference power and a level of a return beam at that time. Then, in recording on an arbitrary location in the user data recording area of the information recording layer in question, the optimum recording power for the mentioned arbitrary location is calculated using a record power used for recording on a location in the neighborhood of said arbitrary location, a level of a return beam detected at that time, the reference power obtained in the test of the recording power, and the level of the return beam obtained at that time. The power of the recording laser beam is controlled such that recording on the mentioned arbitrary location is performed with that optimum recording power. [0023] Further, an information recording apparatus according to the present invention records information on the optical information record medium having the above-described configuration, using a recording laser beam, and comprises: a laser source; an irradiation means that irradiates a recording laser beam coming out of said laser source onto the optical information record medium; a photo detection means for detecting a return beam of said recording laser beam; and a control unit; [0024] The control unit tests the recording power using a recording power test area in a second or deeper information recording layer before recording on a user data recording area of said information recording layer, to obtain a reference power and a level of a return beam at that time. Further, the control unit calculates an optimum recording power for an arbitrary location in the user data recording area of said information recording layer before recording on said arbitrary location, with said optimum recording power being calculated using a recording power used for recording on a location in neighborhood of said arbitrary location, a level of a return beam detected at that time, the reference power obtained in said step of testing the recording power, and the level of the return beam obtained at that time; and controls the recording power such that recording on said arbitrary location is performed with said optimum recording power.
BRIEF DESCRIPTION OF THE DRAWINGS [0025] [0025]FIG. 1 is a block diagram showing a basic configuration of an information recording apparatus used in an embodiment of the present invention; [0026] [0026]FIG. 2 is a schematic diagram showing levels of a return beam of a laser beam when information is recorded on a first information recording layer; [0027] [0027]FIG. 3 is a schematic diagram showing levels of a return beam of a laser beam when information is recorded on a second information recording layer; [0028] [0028]FIG. 4 is a view showing appearance for an optical information record medium used in an embodiment of the present invention; [0029] [0029]FIG. 5 is a schematic view showing recording power test areas of an optical information record medium having three information recording layers; [0030] [0030]FIG. 6 is a schematic view showing recording power test areas of an optical information record medium having three information recording layers; [0031] [0031]FIG. 7 is a cross section showing recording power test areas of the optical information record medium shown in FIG. 6; [0032] [0032]FIG. 8 is a flowchart of a recording power test; [0033] [0033]FIG. 9 is a view for explaining a case where information is recorded on an optical information record medium having two information recording layers; and [0034] [0034]FIG. 10 is a diagram for explaining recording states of an area where spot is irradiated.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0035] Embodiments of the present invention will be described referring to drawings. [0036] [0036]FIG. 1 is a block diagram showing a basic configuration of an information recording apparatus to which an embodiment of the present invention is applied. In the figure, the reference numeral 1 refers to a laser source, 2 to a pickup, 3 to a laser driver; 4 to a photodetector, 5 to a control unit, and 28 to an optical information record medium having a plurality of information recording layers. [0037] As the laser source 1, is used a semiconductor laser, a gas laser, or the like. As the wavelength of the laser, a CD uses a wavelength of 780-830 nm, and a DVD uses a wavelength of 630-650 nm. In order to increase a recording density of the optical information record medium 28, a spot diameter of a laser beam used for recording and reproduction should be smaller. A spot diameter is proportional to the wavelength (λ) of the laser and inversely proportional to the numerical aperture (NA) of the object lens. Here, as an optical disk makes progress toward a higher density, the laser source 1 is required to have a shorter wavelength. And, in the case of a next-generation post-DVD high density optical disk, employment of bluish purple semiconductor laser of 400 nm is considered. [0038] The pickup 2 is an optical system for focusing a laser beam from the laser source 1 on a recording film surface of the optical information record medium 28. Usually, the pickup 2 is integrated with the laser source 1. As mentioned above, the recording density of an optical disk is proportional to the numerical aperture (NA) of the object lens. Thus, as an optical disk becomes of a higher density, the numerical aperture becomes larger. NA is about 0.45 for a CD and about 0.6 for a DVD, while it is considered that NA is about 0.65-0.85 for a next-generation high density optical disk. Of course, any appropriate optical system may be used as a laser irradiation means. [0039] The laser driver 3 is a circuit for driving the laser source 1. Usually, the laser driver 3 is integrated with the laser source 1 and the pickup 2. [0040] The photodetector 4 transforms a return beam of a recording laser beam from the optical information record medium 28, into an electric signal. Based on this return beam, the photodetector 4 detects a reproduction signal recorded on the optical information record medium 28, a servo signal for positioning the focal position of a laser beam irradiated through the pickup 2 onto the information recording surface, and a servo signal for tracing recorded marks. Here, a servo circuit, etc. are not shown. [0041] The control unit 5 performs calculation based on the detection output of the photodetector 4, and, based on the calculation result, generates a control signal for power control of the laser driver 3, controls various component units, and performs other operations. Ordinarily, the control unit 5 comprises a CPU and a memory. [0042] When, in the information recording apparatus having the above-described configuration, information is to be recorded on the first information recording layer of the optical information record medium 28 from the side of the recording laser beam incidence, the control unit 5 controls the laser driver 3 such that the power of the recording laser beam from the laser source 1 becomes predetermined recording power, and controls a drive system of the pickup 2 such that the focal position is adjusted on the first information recording layer. [0043] On the other hand, when information is to be recorded on the second or deeper information recording layer of the optical information record medium 28 from the side of the recording laser beam incidence, the control unit 5 controls the laser driver 3 such that the recording power of the recording laser beam becomes predetermined recording power, based on the optimum (reference) power of the recording laser beam and the return beam of the recording laser beam from the optical information record medium 28. The optimum (reference) power of the recording laser beam has been determined in advance by the below-mentioned recording power test concerning the information recording layer as a target of the recording, and the return beam is detected by the photodetector 4. [0044] Here, no problem will occur if the calculation based on the detection result of the photodetector 4 is finished instantaneously, as well as the power control of the laser driver 3 based on the calculation result. As a matter of fact, however, the laser control is delayed by a time required for such feedback. Thus, at the time of recording on the second or deeper information recording layer of the optical information record medium 28 from the side of the recording laser beam incidence, the control unit 5 stores a power value of a return beam detected by the photodetector 4 at a location where information is recorded, for at least one circumference (one track) of the optical information record medium 28, into a buffer such as a memory. Then, when information is to be recorded at an arbitrary location of the optical information record medium 28, a power value of the return beam in recording at a neighbor location to the above-mentioned arbitrary location where the information is to be recorded is read from the buffer. Then, the laser beam used for recording at the above-mentioned arbitrary location is controlled in its power, based on the power value of the return beam and the optimum power that has been determined in advance concerning the information recording layer as the target of the recording. [0045] Here, the above-mentioned arbitrary location is a location at which the information is to be recorded on the second or deeper information recording layer of the optical information record medium 28. Further, the above-mentioned neighbor location is a location where information was recorded a predetermined time before in relation to the above-mentioned arbitrary location (the location at which the information is to be recorded). [0046] With respect to an arbitrary location on an arbitrary track of an information recording layer of the optical information record medium 28, the above-mentioned neighbor location is a location at which information was recorded the predetermined time before on the same track. Or, with respect to a track including the location (the above-mentioned arbitrary location) at which the information is to be recorded in the information recording layer of the optical information record medium 28, the above-mentioned neighbor location is a location at which information was recorded in a track other than the above-mentioned track. The present embodiment will be described assuming that the arbitrary location lies in an arbitrary track in the second or deeper information recording layer of the optical information record medium 28, and the neighbor location lies in a track (a neighbor track) in the neighborhood of the mentioned arbitrary track. [0047] In the case where data such as video data or audio data are recorded consecutively from an inner track, the control unit 5 controls the power of the recording laser beam for a track in which information is to be recorded, based on a power value of a return beam from the track that lies inwardly next to the above-mentioned track, and the optimum power of the recording laser beam, which has been determined in advance concerning the information recording layer as the target of the recording. [0048] In that case, the power of the recording laser beam is controlled based not on the power value of the return beam from the track in which the information is to be recorded, but on the power value of the return beam from the track that lies inwardly next to that track. Here, when, for example, NA of the object lens is 0.6 and the layer pitch is 50 μm, then, the spot size of the recording laser beam is 60 μm in an information recording layer positioned on the near side (the recording laser beam incidence side) of the information recording layer (which is the second or deeper information recording layer from the side of the recording laser beam incidence) on which the information is to be recorded. Accordingly, when the track pitch of the optical information record medium 28 is 0.74 μm, 80 or more tracks lies in this spot. Thus, it is considered that, even if there exists discrepancy of one track, the power value of the return beam is not largely affected (or, does not differ largely). [0049] Thus, the power value used for controlling the power of the recording laser beam should not necessarily be the power value of the return beam of recording in the neighbor track to the track in which the information is to be recorded. A power value of a return beam of a track several tracks distant from the track in which the information is to be recorded may be used, as far as it is in a predetermined range (for example, a range of errors within several percent) not largely different from the power value of the return beam obtained for the track in which the information is to be recorded by irradiation of the recording laser beam. Here, the difference from the power value of the return beam obtained for the track in which the information is to be recorded by irradiation of the recording laser beam is determined by positional deviation of the portion where the recording laser beam passes in each information recording layer on the laser beam incidence side of the information recording layer as the target of the recording. [0050] Next, operation of controlling the recording power by detection of the return beam will be described in detail, referring to FIGS. 2 and 3. In the following, description is given taking an example where the optical information record medium 28 has two information recording layers. Of course, it can be applied similarly to the case where the optical information record medium 28 has three or more information recording layers. [0051] As described above referring to FIG. 10, a return beam from the second or deeper information recording layer from the side of the recording laser beam incidence is changed in its level (its power value), as an information recording layer positioned on the near side (the laser beam incidence side) of the information recording layer in question changes its transmittance depending on its recording state. [0052] [0052]FIG. 2 is a schematic diagram showing levels of a return beam 11 of the recording laser beam when information is recorded on the first information recording layer from the side of the recording laser beam incidence in the optical information record medium 28. It is seen that a return beam of the recording laser beam is obtained without level fluctuation, and the maximum level Itop and the minimum level Ibottom of the return beam can be considered as constant. The maximum level Itop and the minimum level Ibottom are slightly affected by the length of a record mark and an interval between record marks under recording. However, this influence is limited to an ignorable extent. [0053] [0053]FIG. 3 is a schematic diagram showing levels of a return beam 11 of the recording laser beam when information is recorded on the second information recording layer from the side of the recording laser beam incidence in the optical information record medium 28. The recording laser beam is transmitted through the first information recording layer and reflected by the second information recording layer. This reflected beam is transmitted again through the first information recording layer, and becomes a return beam 12. Thus, the return beam 12 is affected by the recording state of the first information recording layer. [0054] Namely, when a part through which the recording laser beam passes in the first information recording layer is in an entirely unrecorded state, the transmittance of the first information recording layer is lower, and accordingly, quantity of recording laser beam reaching the second information recording layer becomes smaller. As a result, as shown by the part 12 e of FIG. 3 for example, the level of the return beam becomes lower both at the maximum level ItopE and at the minimum level IbottomE. On the other hand, when a part through which the recording laser beam passes in the first information recording layer is in an entirely recorded state, the transmittance of the first information recording layer is higher, and accordingly, quantity of recording laser beam reaching the second information recording layer becomes larger. As a result, as shown by the part 12 r of FIG. 3, the level of the return beam becomes higher both at the maximum level ItopR and at the minimum level IbottomR. [0055] Here, in the part through which the recording laser beam passes in the first information recording layer, the recording laser beam is defocused, and accordingly, the transmittance reflects recording states of a plurality of tracks in the first information recording layer. Thus, transmittance in the first information recording layer changes continuously in the radial direction of the second information recording layer (in other words, in the case (B) shown in FIG. 10, the ratio between the recorded part and the unrecorded part changes continuously). The transmittance of the first information recording layer is proportional to the power of the recording laser beam reaching the second information recording layer, and as a result, the transmittance of the first information recording layer is reflected in the return beam detected by the photodetector 4. Thus, as a matter of fact, in FIG. 3, the level of the return beam changes continuously between the unrecorded part 12 e and the recorded part 12 r of the first information recording layer. [0056] Here, it is assumed, for example, that the initial (reference) power of the recording laser beam is the power P0 that is optimum for recording on the second information recording layer when a part through which the recording laser beam passes in the first information recording layer is in an entirely unrecorded state. When a symbol TR refers to the transmittance of a part through which the recording laser beam is transmitted in the first information recording layer when that part is in an entirely recorded sate, TE to the transmittance of the part through which the recording laser beam is transmitted when that part is in an entirely unrecorded state, and ItopR and ItopE to the maximum levels of the return beam in the states of the transmittances TR and TE, respectively, then, the following expression is obtained, since the recording laser beam passes the first information recording layer twice to become the return beam. I
E [0057] Thus, the following expression shows the rising in the power of the recording laser beam from the case where the recording laser beam transmitting part in the first information recording layer is in the entirely unrecorded state to the case where that part is in the entirely recorded state. (T R /T E)=(I topR /I topE)0.5 [0058] And, the following expression determines the optimum power Popt of the recording laser beam when the recording laser beam transmitting part in the first information recording layer is in the entirely recorded state. P opt =P 0=(T E /T R)=P 0�(I topE /I topR)0.5 [0059] Accordingly, in the present embodiment, the below-mentioned recording power test is performed to obtain the optimum power P0 for recording information on the second information recording layer when the recording laser beam transmitting part in the first information recording layer is in the entirely unrecorded state, and to obtain the level ItopE of the return beam in that case. These obtained values P0 and ItopE are stored into the buffer such as a memory. [0060] When information is to be recorded in a certain track A in the second information recording layer, these stored values P0 and ItopE are used together with a recording power PB used at the time when information was recorded on a track B in the neighborhood of the track A and the maximum level ItopB of the return beam detected at that time by the photodetector 4, for controlling the optimum power Popt of the recording laser beam for the track A to satisfy the following expression. P opt =P 0�(I topE /I' topB)0.5 [0061] where I'topB is the maximum level of the return beam when it is assumed that the recording power PB is same as the recording power P0, and can be obtained from the following expression derived from the above expression. I' topB =I topB�(P B /P 0)2 [0062] By this, the optimum recording can be realized without causing over power to the track A of the second information recording layer. In other words, the optimum recording for recording information on the second information recording area can be realized without depending on the recording state of the first information recording layer. [0063] When information has not been recorded in the track B in the neighborhood of the track A, i.e., when the maximum level ItopB of the return beam has not been obtained yet, then, the initial (reference) power P0 of the recording laser beam is used. [0064] Referring to FIG. 9, an example will be described. When information is to be recorded on the second information recording layer 25 of an optical information record medium 21, the return beam of the recording laser beam 26 is transmitted twice through the first information recording layer 23. First, when a recording laser beam transmitting part in the first information recording layer 23 is in an entirely unrecorded state, then, the transmittance TE of the part in question is unfluctuating value and can be known in advance. For example, it is assumed that TE is 10%. Then, when it is assumed that the optimum power P0 (recording power of the laser source 1) for recording information on the second information recording layer 25 is 10 mW in the case where the recording laser beam transmitting part of the first information recording layer 23 is in the entirely unrecorded state, then, the power PE of the recording laser beam reaching the second information recording layer 25 is 1 mW in that case. [0065] Further, when information is to be recorded on a certain track A of the second information recording layer 25, the transmittance TA of the recording laser beam reaching this track A through the transmitting part of the first information recording layer 23, is a fluctuating value that depends on the ratio between the recorded area and the unrecorded area of the part in question. For example, it is assumed that TA is 40%. In that case, when the recording power P0 (10 mW) of the recording laser beam is not controlled, then, the recording power reaching the track A of the second information recording layer 25 is 4 mW. In other words, it is four times as large as the power PE of the recording laser beam that reaches the second information recording layer 25 in the case where the recording laser beam transmitting part of the first information recording layer 23 is in the entirely unrecorded state. Namely, the ratio of both powers is 1:4. [0066] Now, the following expression calculates the maximum level ItopE of the return beam by the recording laser beam of the power value P0 in the case where the recording laser beam transmitting part of the first information recording layer 23 is in the entirely unrecorded state, assuming that the reflectance of the second information recording layer in an erased state is 50%. Namely, since the level ItopE is the level of the return beam obtained when the recording laser beam is transmitted through the first information recording layer 23, reflected by the second information recording layer 25, and is transmitted again through the first information recording layer 23, the following expression is obtained. I topE =P 0�0.1�0.5�0.1=10�0.005=0.05 mW [0067] Further, the following expression calculates the maximum level ItopA of the return beam by the recording laser beam of the power value P0, which is detected by the photodetector 4 when the recording is performed on a certain track A of the second information recording layer 25, assuming that the reflectance of the second information recording layer in an erased state is 50%. Namely, since the level ItopA is the level of the return beam obtained when the recording laser beam is transmitted through the first information recording layer 23, reflected by the second information recording layer 25, and is transmitted again through the first information recording layer 23, the following expression is obtained. I topA =P 0�0.4�0.5�0.4=10�0.08=0.8 mW [0068] Thus, it becomes 16 times as large as the maximum level ItopE of the return beam by the recording laser beam of the power value P0, which is obtained when the recording laser beam transmitting part of the first information recording layer 23 is in the entirely unrecorded state. Namely, the ratio of both return beam levels is 1:16. [0069] Accordingly, by raising each term of the ratio between the return beam levels to 0.5th power, the ratio becomes equal to the ratio between the recording powers (1:4). Thus, when the power of the recording laser beam is controlled such that information is recorded in the track A of the second information recording layer 25 at a recording power obtained by multiplying the optimum power P0 by (ItopE/I'topB)0.5 , then, information can be recorded with the optimum recording power on the second information recording layer 25 always (i.e., without depending on the recording state of the first information recording layer 23). Here, the power P0 is the optimum power of the recording laser beam in recording information on the second information recording layer 25 in the case where the recording laser beam transmitting part of the first information recording layer 23 is in the entirely unrecorded state. [0070] Further, as described above, ItopB is the maximum level of the return beam obtained when information is recorded in a track B in the neighborhood of the track A, assuming that the recording power PB in recording the information in the track B is same as the recording power P0. [0071] Hereinabove, has been described the case where the recording power on the second information recording layer is controlled by detecting the upper side (i.e., the value of the maximum level) of the waveform of the return beam 12 shown in FIG. 3. However, it is possible to control the recording power by detecting the value of the minimum level of the return beam 12. Similarly to the case where the value of the maximum level of the return beam 12 is used, when the symbol TR refers to the transmittance of a part through which the recording laser beam is transmitted in the first information recording layer when that part is in an entirely recorded state, TE to the transmittance of that recording laser beam transmitting part when that part is in an entirely unrecorded state, and IbottomR and IbottomE to the minimum levels of the return beam in the states of the transmittances TR and TE respectively, then, the following expression is obtained, since the recording laser beam passes the first information recording layer twice to become the return beam. I
E [0072] Thus, the following expression shows the rising in the power of the recording laser beam from the case where the recording laser beam transmitting part of the first information recording layer is in the entirely unrecorded state to the case where that part is in the entirely recorded state. (T R /T E)=(I bottomR /I bottomE)0.5 [0073] Here, similarly to the case where the value of the maximum level of the return beam 12 is used, P0 is the optimum power for recording on the second information recording layer when the recording laser beam transmitting part of the first information recording layer is in the entirely unrecorded state. Then, the following expression gives the optimum power Popt for the recording laser beam when the recording laser beam transmitting part of the first information recording layer is in the entirely recorded state. P opt =P 0�(T E /T R)=P 0�(I bottomE /I bottomR)0.5 [0074] Accordingly, in the present embodiment, the below-mentioned recording power test is performed to obtain the optimum power P0 for recording information on the second information recording layer when the recording laser beam transmitting part in the first information recording layer is in the entirely unrecorded state, and to obtain the minimum level IbottomE of the return beam in that case. These obtained values P0 and IbottomE are stored into the buffer such as a memory. [0075] When information is to be recorded in a certain track A in the second information recording layer, these stored values P0 and IbottomE are used together with a recording power PB used at the time when information was recorded on a track B in the neighborhood of the track A and the minimum level IbottomB of the return beam detected at that time by the photodetector 4, for controlling the optimum power Popt of the recording laser beam for the track A to satisfy the following expression. P opt =P 0�(I bottomE /I' bottomB)0.5 [0076] where I'bottomB is the minimum level of the return beam when it is assumed that the recording power PB is same as the recording power P0, and can be obtained from the following expression derived from the above expression. I' bottomB =I bottomB�(P B /P 0)2 [0077] By this, the optimum recording can be realized without causing over power to the track A of the second information recording layer. In other words, the optimum recording for recording information on the second information recording layer can be realized without depending on the recording state of the first information recording layer. [0078] Further, it is possible to control the recording power for the second information recording layer, by detecting the value of the average level of the waveform of the return beam 12 shown in FIG. 3. Similarly to the case where the value of the maximum level of the return beam 12 is used, when the symbol TR refers to the transmittance of a part through which the recording laser beam is transmitted in the first information recording layer when that part is in an entirely recorded state, TE to the transmittance of that recording laser beam transmitting part when that part is in an entirely unrecorded state, and IaveR and IaveE to the average levels of the return beam in the states of the transmittance TR and TE respectively, then, the following expression is obtained, since the return beam 12 has passed the first information recording layer twice. I
E [0079] Thus, the following expression shows the rising in the power of the recording laser beam from the case where the recording laser beam transmitting part of the first information recording layer is in the entirely unrecorded state to the case that part is in the entirely recorded state. (T R /T E)=(I aveR /I aveE)0.5 [0080] Here, similarly to the case where the value of the maximum level of the return beam 12 is used, P0 is the optimum power for recording on the second information recording layer when the recording laser beam transmitting part of the first information recording layer is in the entirely unrecorded state. Then, the following expression gives the optimum power Popt for the recording laser beam when the recording laser beam transmitting part of the first information recording layer is in the entirely recorded state. P opt =P 0�(T E /T R)=P 0�(I aveE /I aveR)0.5 [0081] Accordingly, in the present embodiment, the below-mentioned recording power test is performed to obtain the optimum power P0 for recording information on the second information recording layer when the recording laser beam transmitting part in the first information recording layer is in the entirely unrecorded state, and to obtain the average level IaveE of the return beam in that case. These obtained values P0 and IaveE are stored into the buffer such as a memory. [0082] When information is to be recorded in a certain track A in the second information recording layer, these store values P0 and IaveE are used together with a recording power PB used at the time when information was recorded on a track B in the neighborhood of the track A and the average level IaveB of the return beam detected at that time by the photodetector 4, for controlling the optimum power Popt of the recording laser beam for the track A to satisfy the following expression. P opt =P 0�(I aveE /I' aveB)0.5 [0083] where I'aveB is the average level of the return beam when it is assumed that the recording power PB is same as the recording power P0, and can be obtained from the following expression derived from the above expression. I' aveB =I aveB�(P B /P 0)2 [0084] The average level of the return beam 12 may be obtained by averaging the level of the return beam 12 detected by the photodetector 4, via a low-pass filter, for example. This low-pass filter may be included in the control unit 5. [0085] Hereinabove, the description has been given taking an example where the optical information record medium 28 has two information recording layers. However, the present invention can be applied similarly to a case where the optical information record medium 28 has three or more information recording layers. [0086] Now, is considered a case where information is recorded on the n-th information recording layer counting from the recording laser beam incidence side in an optical information record medium 28 having m information recording layers (2≦n≦m). Here, a symbol TR(n-1) refers to the transmittance of a recording laser beam transmitting part in the first through (n-1)-th information recording layers when that part is in an entirely recorded state, TE(n-1) to the transmittance of that part when that part is in an entirely unrecorded state, and ItopR and ItopE to the top levels of the return beam in the states of the transmittances TR(n-1) and TE(n-1) respectively. [0087] Then, in this case, the following expression shows the rising in the recording power of the laser beam from the case where the recording laser beam transmitting part in the first through (n-1)-th information recording layers is in the entirely unrecorded state to the case where that part is in the entirely recorded state. (T R(n-1) /T E(n-1))=(I topR /I topE)0.5 [0088] And, the following expression determines the optimum power Popt of the recording laser beam when the recording laser beam transmitting part in the first through (n-1)-th information recording layers is in the entirely recorded state. P opt =P 0�(T E(n-1) /T R(n-1))=P 0�(I topE /I topR)0.5 [0089] Accordingly, the below-mentioned recording power test is performed to obtain the optimum power P0 for recording information on the n-th information recording layer when the recording laser beam transmitting part in the first through (n-1)-th information recording layers is in the entirely unrecorded state, and to obtain the level ItopE of the return beam in that case. These obtained values are stored into the buffer such as a memory. [0090] When information is to be recorded in a certain track A in the n-th information recording layer, these stored values P0 and ItopE are used together with a recording power PB used at the time when information was recorded on a track B in the neighborhood of the track A and the maximum level ItopB of the return beam detected at that time by the photodetector 4, for controlling the optimum power Popt of the recording laser beam for the track A to satisfy the following expression. P opt =P 0�(I topE /I' topB)0.5 [0091] where I'topB is the maximum level of the return beam when it is assumed that the recording power PB is same as the recording power P0, and can be obtained from the following expression derived from the above expression. I' topB =I topB�(P B /P 0)2 [0092] By this, the optimum recording can be realized without causing over power to the track A of the n-th information recording layer. In other words, the optimum recording for recording information on the n-th information recording layer can be realized without depending on the recording states of the first through (n-1)-th information recording layers. [0093] As described above, the optimum power P0 is the optimum power of the recording laser beam in recording information on the n-th information recording layer in the case where the recording laser beam transmitting part of the first through (n-1)-th information recording layers is in the entirely unrecorded state. Further, the level ItopE (or, IbottomE or IavecE) is the maximum (minimum or average) level of the return beam obtained when the recording laser beam transmitting part in the first through (n-1)-th information recording layer is entirely in the unrecorded state. In the present embodiments, these levels are detected in advance by test writing or the like, and stored into the memory or the like provided to the control unit 5. Accordingly, the optical information record medium used in the present embodiments is provided with a test writing area (power test area) in each second or deeper information recording layer. [0094] [0094]FIG. 4 is a view showing appearance of an optical information record medium 28 used in an embodiment of the present invention. This optical information record medium 28 is provided with a power test area 29 inside the innermost part of a user data recording area 30 and/or outside the outermost part of the user data recording area 30. In the example shown, the power test area 29 is provided both inside and outside the user data recording area 30. According to a disk format, the user data recording area 30 and the power test area 29 may be mixed. [0095] In the present embodiment, recording power is tested not in the user data recording area 30 but in the power test area 29, before user data are recorded on the second or deeper information recording layer of the optical information record medium 28 having such structure, to determine the optimum power P0 and to detect the maximum level ItopE (or the minimum level IbottomE or the average level IaveE) of the return beam. The obtained optimum power P0 and the maximum level ItopE (or the minimum level IbottomE or the average level IaveE) of the return beam are stored into the memory or the like provided to the control unit 5. When user data is to be recorded on the second or deeper information recording layer, these data are used together with a recording power PB that was used at the time of recording on a track B just inside or outside the track in which the user data in question are to be recorded, and the maximum level ItopB (or the minimum level IbottomB or the average level IaveB) of the return beam detected at that time by the photodetector 4 in the case where the first layer is in an recorded state, in order to calculate the optimum power Popt of the recording laser beam according to the above-described operational expressions. Then, based on the calculation result, the power of the recording laser beam is controlled. [0096] As described above, the optimum power P0 is the power of the recording laser beam that is optimum for recording information on the n-th information recording layer, when the recording laser beam transmitting part in the first through (n-1)-th information recording layers is in an entirely unrecorded state. Thus, the part (transmitting part) in the first through (n-1)-th layers, through which the laser beam is transmitted to reach the measuring part of the n-th layer, should be in the recording state of the lowest transmittance, i.e., the unrecorded state in the information recording layer concerned. Accordingly, dedicated power test areas provided respectively in the second and deeper information recording layers should be located in respective positions that do not overlap each other seen from the laser beam incidence side. [0097] [0097]FIG. 5 is a schematic view showing power test areas in the case where three information recording layers exist. In the figure, the reference numeral 31 refers to a power test area in the second information recording layer, and 32 to a power test area in the third information recording layer. Of course, power test areas may be formed similarly in the first information recording layer too. Further, a method of dividing a power test area is not limited to the shown method where an area is divided in the circumferential direction. Any dividing method may be employed as far as dedicated power test areas provided respectively in the information recording layers are located in respective positions that do not overlap each other seen from the laser beam incidence side. An appropriate dividing pattern may be employed, such as a pattern that is divided into areas located in different positions in the radial direction, for example. However, in the case of the optical information record medium 28 whose appearance is shown in FIG. 4, the medium 28 has two information recording layers. Accordingly, one power test area 29 is sufficient in this case, without requiring division as shown in FIG. 5. [0098] Hereinabove, the power test areas 29 are used to obtain the optimum power P0 for the n-th information recording layer when the recording laser beam transmitting part in the first through (n-1)-th information recording layers is in the state of the lowest transmittance, and to obtain the maximum level ItopE (or the minimum level IbottomE or the average level IaveE) of the return beam in that case. However, it is possible to obtain the optimum power P0 for the n-th information recording layer when the recording laser beam transmitting part in the first through (n-1)-th information recording layers is in the state of the highest transmittance (i.e., the part is in an entirely recorded state, namely, amorphous) and to obtain the maximum level ItopR (or the minimum level IbottomR or the average level IaveR) of the return beam in that case, storing the obtained values into the memory or the like provided to the control unit 5. When user data is to be recorded on the n-th or deeper information recording layer, these data are used together with a recording power PB that was used at the time of recording on a track B just inside or outside the track A in which the user data in question are to be recorded and the maximum level ItopB (or the minimum level IbottomB or the average level IaveB) of the return beam detected at that time by the photodetector 4, in order to calculate the optimum power Popt of the recording laser beam according to the following expression and to control the power of the recording laser beam based on the calculation result. P opt =P 0�(I' topB /I topR)0.5 [0099] where I'topB is the maximum level of the return beam when it is assumed that the recording power PB is same as the recording power P0, and can be obtained from the following expression. I' topB =I topB�(P B /P 0)2 [0100] Further, to improve the accuracy of adjustment of the power of the recording laser beam, both the optimum power P0 for the n-th information recording layer in the case where the recording laser beam transmitting part in the first through (n-1)-th information recording layers has the lowest transmittance (in an entirely unrecorded state) and the optimum power Pa for the n-th information recording layer in the case where that part has the highest transmittance (in an entirely recorded state) may be obtained. These data may be used to obtain the optimum power Popt of the recording laser beam for a track A in the n-th information recording layer, according to the following expression. P opt =P 0+((P a −P 0)/(I topR −I topE))�I' topB [0101] In this case, the power test areas become as shown in FIGS. 6 and 7 (in the case of three information recording layers). Here, FIG. 7 is a schematic cross section showing the power test areas of FIG. 6. In FIGS. 6 and 7, the reference numeral 33 refers to a P0 test area in the second information recording layer, 34 to a Pa test area in the second information recording layer, 35 to a P0 test area in the third information recording layer, and 36 to a Pa test area in the third information recording layer. Further, the reference numeral 37 refers to crystal parts, and 38 to amorphous parts. In comparison with FIG. 6, like reference numerals are used for like parts, omitting their explanation. [0102] Here, it is favorable that initialization to respective states of the crystal parts 37 and amorphous parts 38 is performed by an initialization apparatus and a drive. Further, the recorded state (of the amorphous parts 38) may be realized at the same time with formatting etc. when a user buys an optical information record medium and mounts it on the drive for the first time. Further, it is assumed that effect of a state (recorded state/unrecorded state) of the n-th information recording layer for which the power test is performed is sufficiently small in comparison with the effect of the state of the (n-1)-th information recording layer. [0103] Hereinabove, it is assumed that an information recording layer has a lower transmittance (higher reflectance) when it is in an unrecorded state, and has a higher transmittance (lower reflectance) when it is in a recorded state. However, the present invention can be applied similarly to a medium that has a higher transmittance (lower reflectance) in an unrecorded state and has a lower transmittance (higher reflectance) in a recorded state. [0104] Next, will be described operation of the recording power test in the information recording apparatus shown in FIG. 1. [0105] For the sake of simplicity, it is assumed here that the optical information record medium 28 is subjected to rotation control to have a constant linear velocity (CLV). Namely, it is assumed that power of the recording laser beam is same for a same circumference (track). [0106] [0106]FIG. 8 is a flowchart for explaining the operation of the recording power test in the information recording apparatus shown in FIG. 1. [0107] First, the control unit 5 starts the recording power test (Step 1), and controls the pickup 2 to seek a power test area 29 in the n-th information recording layer (n≧2) of the optical information record medium 28 (Step 2). Further, as a setting parameter of the value of the recording power of the recording laser beam, the control unit 5 sets the initial value of laser driving current to the laser driver 3. This makes the laser source 1 output the recording laser beam having the recording power of the initial value. The recording laser beam is irradiated on the power test area 29 of the n-th information recording layer, through the pickup 2. Then, the control unit 5 controls the pickup 2 and the laser driver 3 to record the test writing into the power test area 29 of the n-th information recording layer (Step 3). [0108] Here, it is favorable that the set value of the test writing is recorded with five recording points, i.e., the maker recommendation recording power recorded usually in a lead-in area or the like of the optical disk, and recording powers of �5% and �10%. Of course, use of the maker recommendation recording power, and �5% and �10% recording powers is an example, and the present invention is not limited to this example. Each time when the laser beam having recording power of a set value of the test writing is irradiated onto a power test area 29, the level of the return beam detected by the photodetector 4 is held temporally in control unit 5. [0109] Then, the control unit 5 controls the pickup 2 to read the data recorded in the power test area 29 for each set value of the test writing (Step 4). Then, for each set value of the test writing, a reproduced signal outputted from the photodetector 4 is used to measure and calculate data (such as asymmetry, for example) usable as a standard of the recording state (Step 5). [0110] Next, the control unit 5 selects an asymmetry value that is close to a prescribed optimum asymmetry value, out of the asymmetry values measured and calculated for each set value of the test writing (Step 6). When there is not an asymmetry value close to the prescribed optimum asymmetry value, then, as shown by the path of the dotted arrow in the figure, the flow returns to Step 3 to set again the recording powers in a wider range than the initially-set range, and Step 4 and the following steps are executed again. Here, as the criterion of judgment for determining the optimum power of the recording laser beam, jitter or pulse width of the reproduced signal may be used other than the above-mentioned asymmetry. [0111] Next, the control unit 5 decides the test writing set value corresponding to the selected asymmetry value as the optimum power P0 of the recording laser beam. And, this optimum power P0 and the maximum level ItopE (or the minimum level IbottomE or the average level IaveE) of the return beam at that time are stored into the memory or the like (Step 7). This finishes the recording power test. [0112] In the case of the constant angular velocity (CAV) disk rotation control, the linear velocity changes continuously in the radial direction. Thus, it is difficult to test the recording power at the linear velocity corresponding to a recording location (circumference or track). In that case, the recording power may be tested for the innermost track having the smallest linear velocity and for the outermost track having the largest linear velocity. And, then, interpolation is employed to obtain the optimum power for each track. For example, when a symbol Pin refers to the optimum power for the innermost track, Pout to the optimum power for the outermost track, LVin to the linear velocity at the innermost track, LVout to the linear velocity at the outermost track, and LVx to a linear velocity at a track x, then, the optimum power Px for the track x can be calculated by the following expression. P x =P in+((P out −P in)/(LV out −LV in))�LV x [0113] According to the present invention, as described above, when information is to be recorded on a second or deeper information recording layer of an optical information record medium having two or more information recording layers, it is possible to control appropriately the power of the recording laser beam, even if quantity of transmitted beam is changed depending on the recording state of the recording layers positioned on the incidence side of the information recording layer on which the information is to be recorded. Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS5614938 *Jun 5, 1995Mar 25, 1997Hitachi, Ltd.Three-dimensional recording and reproducing apparatusUS6052347 *Feb 24, 1997Apr 18, 2000Ricoh Company, Ltd.Method and apparatus for detecting optimum recording power for an optical disk* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS7035185Aug 27, 2004Apr 25, 2006Ricoh Company, Ltd.Optical information recording apparatus, information processing apparatus, optical information recording medium, optical information recording method, and computer-readable storage mediumUS7209420Aug 27, 2004Apr 24, 2007Ricoh Company, Ltd.Optical information recording on an optical information recording medium having multiple layersUS7245570 *Feb 9, 2004Jul 17, 2007Hitachi, Ltd.Information recording method and information recording apparatusUS7257063 *Aug 16, 2005Aug 14, 2007Samsung Electronics Co., Ltd.Apparatus for reproducing data from information storage medium having multiple storage layers with optimal power control (OPC) areas and buffer areasUS7257064 *Aug 16, 2005Aug 14, 2007Samsung Electronics Co., Ltd.Recording/reproducing apparatus which records/reproduces data with respect to multi-layer information storage medium having optical power control areasUS7257065 *May 11, 2006Aug 14, 2007Samsung Electronics Co., Ltd.Method of recording and/or reproducing data with respect to a multi-layer information storage medium having optimal power control areasUS7263045 *May 12, 2006Aug 28, 2007Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording and/or reproducing dataUS7269109 *May 12, 2006Sep 11, 2007Samsung Electronics Co., Ltd.Apparatus for reproducing data from information storage medium having multiple storage layers with optimal power control (OPC) areas and buffer areasUS7274638 *Jun 14, 2004Sep 25, 2007Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording and/or reproducing dataUS7286454 *Jun 25, 2004Oct 23, 2007Samsung Electronics Co., Ltd.Information storage mediumUS7286455 *Jun 16, 2005Oct 23, 2007Matsushita Electric Industrial Co., Ltd.Information recording medium, recording apparatus, recording method and reproduction method utilizing test areas of respective layers provided at different radial positionsUS7286456 *Aug 15, 2005Oct 23, 2007Samsung Electronics Co., Ltd.Information storage medium, method and apparatus reproducing data there fromUS7286457 *May 12, 2006Oct 23, 2007Samsung Electronics Co., Ltd.Information storage mediumUS7289403 *May 12, 2006Oct 30, 2007Samsung Electronics Co., Ltd.Information storage mediumUS7304929Sep 3, 2004Dec 4, 2007Ricoh Company, Ltd.Optical information recording medium, an optical information recording apparatus, an information processing apparatus, program and information recording methodUS7327650 *Jun 25, 2004Feb 5, 2008Samsung Electronics Co., Ltd.Multi-layer information storage medium having optimal power control areas, and an apparatus to record and/or read with respect to the information storage mediumUS7327652 *May 11, 2006Feb 5, 2008Samsung Electronics Co., Ltd.Method of recording data on a multi-layer information storage medium having optimal power control areasUS7327653 *May 12, 2006Feb 5, 2008Samsung Electronics Co., Ltd.Information storage medium having storage layer with optical power control area, and recording apparatus to record data with respect to information storage mediumUS7339865 *May 10, 2006Mar 4, 2008Samsung Electronics Co., Ltd.Method of reproducing data from information storage mediumUS7339866 *May 12, 2006Mar 4, 2008Samsung Electronics Co., Ltd.Method of recording data on Information storage medium having multiple storage layers with optimal power control (opc) areas and buffer areasUS7345973 *Jun 18, 2004Mar 18, 2008Koninklijke Philips Electronics N.V.Multi-layer writable optical record carrier with an optimum power calibration area, and method and apparatus for forming optimum power calibration areas on such a record carrierUS7355943 *May 11, 2006Apr 8, 2008Samsung Electronics Co., Ltd.Method of recording and/or reproducing data with respect to multi-layer information storage medium having optimal power control areasUS7376059Sep 17, 2007May 20, 2008Samsung Electronics Co., Ltd.Method of obtaining optimal recording condition with respect to information storage medium having storage layer with optical power control areaUS7382701 *May 10, 2006Jun 3, 2008Samsung Electronics Co., Ltd.Method to record data on and/or perform optimal power control for information storage mediumUS7382702 *May 10, 2006Jun 3, 2008Samsung Electronics Co., Ltd.Apparatus to reproduce data from a recordable information storage mediumUS7385891 *Dec 7, 2004Jun 10, 2008Samsung Electronics Co., Ltd.Method, a medium, and an apparatus to record/reproduce data on/from a portion of the medium through which a test beam is passed while determining an optimum powerUS7391705Nov 7, 2005Jun 24, 2008Ricoh Company, Ltd.Optical information recording apparatus, information processing apparatus, optical information recording medium, optical information recording method, and computer-readable storage mediumUS7403457 *Sep 30, 2004Jul 22, 2008Ricoh Company, Ltd.Method and apparatus for recording information with a multi-layer structureUS7408856Jul 6, 2007Aug 5, 2008Samsung Electronics Co., Ltd.Method of recording data on information storage medium having multiple storage layers with optimal power control (OPC) areas and buffer areasUS7408864Jul 20, 2007Aug 5, 2008Samsung Electronics Co., Ltd.Information storage medium having optimal power control areasUS7414937Sep 19, 2007Aug 19, 2008Samsung Electronics Co., Ltd.Information storage medium having multiple storage layers with optical power control areas, and recording apparatus to record data with respect to information storage mediumUS7423944Sep 13, 2007Sep 9, 2008Samsung Electronics Co., Ltd.Information storage medium having storage layer with optical power control area, and recording apparatus to record data with respect to information storage mediumUS7426162Jul 9, 2007Sep 16, 2008Samsung Electronics Co., Ltd.Method of recording and/or reproducing data with respect to multi-layer information storage medium having optimal power control areasUS7440368Apr 4, 2008Oct 21, 2008Samsung Electronics Co., Ltd.Information storage mediumUS7440369 *Dec 20, 2004Oct 21, 2008Pioneer CorporationInformation recording device and method, and computer programUS7450481Jul 6, 2007Nov 11, 2008Samsung Electronics Co., Ltd.Apparatus for reproducing data from information storage medium having multiple storage layers with optimal power control (OPC) areas and buffer areasUS7466641Jul 20, 2007Dec 16, 2008Samsung Electronics Co., Ltd.Information storage medium having optimal power control areasUS7483354 *Dec 20, 2005Jan 27, 2009Teac CorporationOptical disk apparatus for recording data on multilayer optical diskUS7489605 *Aug 17, 2005Feb 10, 2009Samsung Electronics Co., Ltd.Method and apparatus of reproducing data from an information storage mediumUS7489606Jul 19, 2007Feb 10, 2009Samsung Electronics Co., Ltd.Information storage medium having multiple storage layers with optimal power control (OPC) areas and buffer areasUS7492680Jul 6, 2007Feb 17, 2009Samsung Electronics Co., Ltd.Method of recording data on information storage medium having multiple storage layers with optimal power control (OPC) areas and buffer areasUS7492681Jul 9, 2007Feb 17, 2009Samsung Electronics Co., Ltd.Information storage mediumUS7496012Sep 17, 2007Feb 24, 2009Samsung Electronics Co., Ltd.Information storage medium having storage layer with optical power control area, and recording apparatus to record data with respect to information storage mediumUS7496013Apr 4, 2008Feb 24, 2009Samsung Electronics Co., Ltd.Information storage mediumUS7518962Jul 9, 2007Apr 14, 2009Samsung Electronics Co., Ltd.Method of recording and/or reproducing data with respect to a multi-layer information storage medium having optimal power control areasUS7522496Sep 13, 2007Apr 21, 2009Samsung Electronics Co., Ltd.Method of obtaining optimal recording condition with respect to information storage medium having multiple storage layers with optical power control areasUS7522497Feb 6, 2008Apr 21, 2009Samsung Electronics Co., Ltd.Apparatus for reproducing data from information storage medium having multiple storage layers with optimal power control (OPC) areas and buffer areasUS7522500Dec 17, 2007Apr 21, 2009Samsung Electronics Co., Ltd.Method of recording and/or reproducing data with respect to multi-layer information storage medium having optimal power control areasUS7522505 *Jun 16, 2005Apr 21, 2009Samsung Electronics Co., Ltd.Optical memory deviceUS7525888Apr 23, 2007Apr 28, 2009Ricoh Company, Ltd.Optical information recording medium, an optical information recording apparatus, an information processing apparatus, program and information recording methodUS7545717Feb 20, 2007Jun 9, 2009Ricoh Company, Ltd.Optical information recording apparatus for recording on an optical information recording medium having multiple layersUS7583573Jul 29, 2008Sep 1, 2009Samsung Electronics Co., Ltd.Information storage medium having multiple storage layers with optimal power control (OPC) areas and buffer areasUS7680020 *Mar 16, 2010Victor Company Of Japan, Ltd.Method of recording a signal on an information recording medium, and method of recording and reproducing a signal on and from an information recording mediumUS7715291 *Dec 5, 2006May 11, 2010Panasonic CorporationMulti-layered information recording medium, recording apparatus, and recording methodUS7719935Jul 22, 2008May 18, 2010Samsung Electronics Co., Ltd.Information storage medium having multiple information storage layers with optimal power control area, and recording apparatus to record data with respect to the information storage mediumUS7889610Dec 29, 2009Feb 15, 2011Panasonic CorporationMulti-layered information recording medium, recording apparatus, and recording methodUS7894315May 25, 2006Feb 22, 2011Ricoh Company, Ltd.Optical disk, recording method, recording medium, and optical disk unit, for recording information on multilayer optical diskUS8034530Feb 14, 2003Oct 11, 2011Tdk CorporationMethod of recording information in optical recording medium, information recording, apparatus and optical recording mediumUS8121002Dec 29, 2010Feb 21, 2012Panasonic CorporationMulti-layered information recording medium, recording apparatus, and recording methodUS8139455 *May 10, 2006Mar 20, 2012Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording/reproducing data on/from the sameUS8169883 *Jun 25, 2004May 1, 2012Panasonic CorporationOptical disk, method for manufacturing the same, and method for recording and method for reproducing data using optical diskUS8194516Mar 31, 2010Jun 5, 2012Pioneer CorporationInformation recording apparatus and methodUS8270271Sep 18, 2012Ricoh Company, Ltd.Optical recording medium and information recording methodUS8351314Jan 8, 2013Samsung Electronics Co., Ltd.Optical disc having plurality of recording layers, and method and apparatus for recording data thereonUS8369195 *Feb 5, 2013Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording/reproducing data on/from the sameUS8385167 *May 10, 2006Feb 26, 2013Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording/reproducing data on/from the sameUS8432778May 10, 2006Apr 30, 2013Samsung Electronics Co., Ltd.Optical disc having plurality of recording layers, and method and apparatus for recording data thereonUS8446805Dec 29, 2009May 21, 2013Victor Company Of Japan, Ltd.Method of recording information on a recording medium including the recordation of a test signal thereonUS8867326Nov 11, 2011Oct 21, 2014Victor Company Of Japan, Ltd.Apparatus for reproducing a signal from a disc-shaped information recording medium having a plurality of recording layers with different areasUS9286929 *Sep 30, 2009Mar 15, 2016Hitachi Consumer Electronics Co., Ltd.Multilayered optical disk and its recording methodUS20040085874 *Oct 24, 2003May 6, 2004Matsushita Electric Industrial Co., Ltd.Optical information recording medium, optical recording and reproducing method and optical recording and reproducing apparatusUS20040264317 *Jun 25, 2004Dec 30, 2004Samsung Electronics Co., Ltd.Information storage mediumUS20040264339 *Jun 25, 2004Dec 30, 2004Matsushita Electric Industrial Co., Ltd.Optical disk, method for manufacturing the same, and method for recording and method for reproducing data using optical diskUS20050013222 *Jun 14, 2004Jan 20, 2005Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording and/or reproducing dataUS20050013223 *Jun 25, 2004Jan 20, 2005Samsung Electronics Co., Ltd.Information storage mediumUS20050025012 *Aug 27, 2004Feb 3, 2005Teruyasu WatabeOptical information recording apparatus, information processing apparatus, optical information recording medium, optical information recording method, and computer-readable storage mediumUS20050025013 *Sep 3, 2004Feb 3, 2005Norihiro YamamotoStable write trial process with respect to optical record mediumUS20050025014 *Aug 27, 2004Feb 3, 2005Teruyasu WatabeOptical information recording apparatus, optical information recording medium, optical information recording method, and computer-readable information storage mediumUS20050030862 *Sep 3, 2004Feb 10, 2005Masaki NinomiyaOptical information recording medium, an optical information recording apparatus, an information processing apparatus, program and information recording methodUS20050041555 *Sep 30, 2004Feb 24, 2005Ippei OgawaOptical recording medium and information recording methodUS20050073935 *Feb 14, 2003Apr 7, 2005Hideaki MiuraMethod for reproducing information from optical recording medium, information reproducer, and optical record mediumUS20050088953 *Feb 9, 2004Apr 28, 2005Hitachi., Ltd.Information recording method and information recording apparatusUS20050089798 *Feb 14, 2003Apr 28, 2005Hideaki MiuraMethod for recording information on optical recording medium, information recorder, and optical recording mediumUS20050195709 *Dec 7, 2004Sep 8, 2005Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording/reproducing data on/from the sameUS20050226133 *Mar 16, 2005Oct 13, 2005Victor Company Of Japan, Ltd.Information recording medium, and method and apparatus for recording a signal thereonUS20050232108 *Jun 16, 2005Oct 20, 2005Matsushita Electric Industrial Co., Ltd.Information recording medium, recording apparatus, reproduction apparatus, recording method, and reproduction methodUS20050237883 *Dec 16, 2004Oct 27, 2005Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording/reproducing data on/from the sameUS20050270933 *Aug 15, 2005Dec 8, 2005Samsung Electronics Co., Ltd.Information storage medium, method and apparatus reproducing data there fromUS20050270934 *Aug 16, 2005Dec 8, 2005Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording and/or reproducing dataUS20050270935 *Aug 16, 2005Dec 8, 2005Samsung Electronics Co., Ltd.Information storage mediumUS20050276188 *Aug 17, 2005Dec 15, 2005Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording/reproducing data on/from the sameUS20050281153 *Jun 16, 2005Dec 22, 2005Yukihisa NakajoOptical memory deviceUS20050286364 *Aug 17, 2005Dec 29, 2005Samsung Electronics Co., Ltd.Optical disc having plurality of recording layers, and method and apparatus for recording data thereonUS20050286399 *Oct 18, 2004Dec 29, 2005Samsung Electronics Co, Ltd.Optical disc having plurality of recording layers, and method and apparatus for recording data thereonUS20060062113 *Nov 7, 2005Mar 23, 2006Teruyasu WatabeOptical information recording apparatus, information processing apparatus, optical information recording medium, optical information recording method, and computer-readable storage mediumUS20060140085 *Dec 20, 2005Jun 29, 2006Teac CorporationOptical disk apparatus for recording data on multilayer optical diskUS20060181983 *Mar 11, 2004Aug 17, 2006Koninklijke Philips Electronics N.V.Optimum power control for multilayer optical discUS20060198266 *May 8, 2006Sep 7, 2006Samsung Electronics Co., Ltd.Optical disc having plurality of recording layers, and method and apparatus for recording data thereonUS20060203648 *May 10, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording/reproducing data on/from the sameUS20060203649 *May 10, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording/reproducing data on/from the sameUS20060203650 *May 10, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording/reproducing data on/from the sameUS20060203651 *May 10, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording/reproducing data on/from the sameUS20060203652 *May 11, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Information storage mediumUS20060203653 *May 11, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Information storage mediumUS20060203654 *May 11, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Information storage mediumUS20060203655 *May 12, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Information storage mediumUS20060203656 *May 12, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording and/or reproducing dataUS20060203657 *May 12, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording and/or reproducing dataUS20060203658 *May 12, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Information storage mediumUS20060203659 *May 12, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording and/or reproducing dataUS20060203671 *May 10, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Optical disc having plurality of recording layers, and method and apparatus for recording data thereonUS20060203672 *May 10, 2006Sep 14, 2006Samsung Electronics Co., Ltd.Optical disc having plurality of recording layers, and method and apparatus for recording data thereonUS20060227685 *May 10, 2006Oct 12, 2006Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording/reproducing data on/from the sameUS20060227689 *May 10, 2006Oct 12, 2006Samsung Electronics Co., Ltd.Information storage medium and method and apparatus for recording/reproducing data on/from the sameUS20060233076 *May 12, 2006Oct 19, 2006Samsung Electronics Co., Ltd.Information storage mediumUS20070041308 *Oct 1, 2004Feb 22, 2007Eiji MuramatsuInformation recording medium, information recording device and methodUS20070064560 *Dec 20, 2004Mar 22, 2007Eiji MuramatsuInformation recording device and method, and computer programUS20070086325 *Dec 5, 2006Apr 19, 2007Matsushita Electric Industrial Co., Ltd.Multi-layered information recording medium, recording apparatus, and recording methodUS20070104057 *Jun 18, 2004May 10, 2007Koninklijke Philips Electronics N.V.Multi-layer writable optical record carrier with an optimum power calibration area, and method and apparatus for forming optimum power calibration areas on such a record carrierUS20070104058 *Sep 28, 2004May 10, 2007Kunihiko HorikawaInformation recording medium, information recording device and method, information recording/reproducing device and method, and computer programUS20070147208 *Feb 20, 2007Jun 28, 2007Teruyasu WatabeOptical information recording apparatus, optical information recording medium, optical information recording method, and computer-readable information storage mediumUS20070206482 *Mar 2, 2007Sep 6, 2007Tdk CorporationMethod and apparatus for reproducing optical recording mediumUS20070223347 *Apr 23, 2007Sep 27, 2007Masaki NinomiyaOptical information recording medium, an optical information recording apparatus, an information processing apparatus, program and information recording methodUS20070258342 *Jul 20, 2007Nov 8, 2007Samsung Electronics Co., Ltd.Information storage mediumUS20080002543 *Sep 13, 2007Jan 3, 2008Samsung Electronics Co., Ltd.Method of obtaining optimal recording condition with respect to information storage medium having multiple storage layers with optical power control areasUS20080002544 *Sep 13, 2007Jan 3, 2008Samsung Electronics Co., Ltd.Information storage medium having storage layer with optical power control area, and recording apparatus to record data with respect to information storage mediumUS20080008068 *Sep 17, 2007Jan 10, 2008Samsung Electronics Co., Ltd.Information storage medium having storage layer with optical power control area, and recording apparatus to record data with respect to information storage mediumUS20080008069 *Sep 19, 2007Jan 10, 2008Samsung Electronics Co., Ltd.Information storage medium having multiple storage layers with optical power control areas, and recording apparatus to record data with respect to information storage mediumUS20080013419 *Jul 6, 2007Jan 17, 2008Samsung Electronics Co., Ltd.Method of recording data on information storage medium having multiple storage layers with optimal power control (opc) areas and buffer areasUS20080013420 *Jul 6, 2007Jan 17, 2008Samsung Electronics Co., Ltd.Method of recording data on information storage medium having multiple storage layers with optimal power control (opc) areas and buffer areasUS20080013421 *Jul 9, 2007Jan 17, 2008Samsung Electronics Co., Ltd.Information storage mediumUS20080013422 *Jul 9, 2007Jan 17, 2008Samsung Electronics Co., Ltd.Method of recording and/or reproducing data with respect to multi-layer information storage medium having optimal power control areasUS20080013423 *Jul 19, 2007Jan 17, 2008Samsung Electronics Co., Ltd.Information storage medium having multiple storage layers with optimal power control (opc) areas and buffer areasUS20080013425 *Jul 6, 2007Jan 17, 2008Samsung Electronics Co, Ltd.Apparatus for reproducing data from information storage medium having multiple storage layers with optimal power control (opc) areas and buffer areasUS20080013426 *Jul 9, 2007Jan 17, 2008Samsung Electronics Co., Ltd.Method of recording and/or reproducing data with respect to a multi-layer information storage medium having optimal power control areasUS20080043591 *Sep 17, 2007Feb 21, 2008Samsung Electronics Co., LtdMethod of obtaining optimal recording condition with respect to information storage medium having storage layer with optical power control areaUS20080068948 *May 25, 2006Mar 20, 2008Masaki KatoOptical Disk, Recording Method, Recording Medium, And Optical Disk UnitUS20080074972 *Sep 7, 2005Mar 27, 2008Pioneer CorporationInformation Recording Medium, Information Recording Device and Method and Computer ProgramUS20080094973 *Dec 17, 2007Apr 24, 2008Samsung Electronics Co., Ltd.Method of recording and/or reproducing data with respect to multi-layer information storage medium having optimal power control areasUS20080144457 *Feb 6, 2008Jun 19, 2008Samsung Electronics Co., Ltd.Apparatus for reproducing data from information storage medium having multiple storage layers with optimal power control (opc) areas and buffer areasUS20080181068 *Apr 4, 2008Jul 31, 2008Samsung Electronics Co., Ltd.Information storage mediumUS20080273431 *Jul 22, 2008Nov 6, 2008Samsung Electronics Co., Ltd.Information storage medium having storage layer with optical power control area, and recording apparatus to record data with respect to information storage mediumUS20080279065 *Jul 29, 2008Nov 13, 2008Samsung Electronics Co., Ltd.Information storage medium having multiple storage layers with optimal power control (opc) areas and buffer areasUS20090154320 *May 6, 2008Jun 18, 2009Ippei OgawaOptical recording medium and information recording methodUS20100103787 *Dec 29, 2009Apr 29, 2010Panasonic CorporationMulti-layered information recording medium, recording apparatus, and recording methodUS20100110852 *Dec 29, 2009May 6, 2010Victor Company Of Japan, Ltd.Information recording medium, and method and apparatus for recording a signal thereonUS20100188950 *Mar 31, 2010Jul 29, 2010Pioneer CorporationInformation recording apparatus and methodUS20100290331 *Mar 19, 2010Nov 18, 2010Yasuhiro KaizakiWiring structure and optical disk apparatusUS20100309764 *Dec 9, 2010Harukazu MiyamotoMultilayered optical disk and its recording methodUS20110090771 *Dec 29, 2010Apr 21, 2011Panasonic CorporationMulti-layered information recording medium, recording apparatus, and recording methodUSRE41246Jan 30, 2009Apr 20, 2010Panasonic CorporationInformation recording medium, recording apparatus, reproduction apparatus, recording method, and reproduction methodCN1890717BOct 1, 2004May 12, 2010日本先锋公司Information recording apparatus and method* Cited by examinerClassifications U.S. Classification369/47.53, G9B/7.101, G9B/7.033, G9B/7.014, G9B/7.168International ClassificationG11B7/125, G11B7/24038, G11B7/24, G11B7/007, G11B7/0045Cooperative ClassificationG11B7/24038, G11B7/00454, G11B7/00736, G11B7/1267European ClassificationG11B7/1267, G11B7/24038, G11B7/007R, G11B7/0045PLegal EventsDateCodeEventDescriptionMar 19, 2002ASAssignmentOwner name: NIPPON COLUMBIA CO., LTD., JAPANFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:NAKANO, KAZUHIKO;REEL/FRAME:012713/0641Effective date: 20020305RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google 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