JP4335832B2 - Optical recording medium, information recording apparatus, and information reproducing apparatus - Google Patents

Description

  The present application belongs to the technical field of an optical recording medium capable of recording information, an information recording apparatus for recording information on the optical recording medium, and an information reproducing apparatus for reproducing information from the optical recording medium.

  For example, in optical recording media such as CD-ROM (Compact Disc-Read Only Memory), CD-R (Compact Disc-Recordable), DVD-ROM, and DVD-R, as disclosed in Patent Documents 1 and 2. An optical recording medium such as a multilayer type or dual layer type optical disc in which a plurality of recording layers are laminated or bonded on the same substrate has also been developed. In an information recording apparatus such as a DVD recorder that performs recording on such a dual-layer type, that is, a two-layer type optical disc, the foremost side when viewed from the laser beam irradiation side (that is, the side close to the optical pickup) The recording laser beam is focused on the first recording layer (referred to as “L0 layer” in this application as appropriate) located at, thereby irreversible change recording method or rewriting by heating or the like to the L0 layer. A second recording layer (which is appropriately referred to as “L1 layer” in the present application) that is recorded in a possible manner and is located on the far side of the L0 layer (that is, the side far from the optical pickup) when viewed from the laser beam irradiation side through the L0 layer or the like. By focusing the laser beam, the information is recorded on the L1 layer by a non-reversible change recording method such as heating or a rewritable method.

In addition, when information is recorded on the L1 layer in a DVD-R dual-layer disc, information must be recorded on the L0 layer at the same radial position as the L1 layer to be recorded. If even a portion where no information is recorded on the L0 layer is applied to the radial position where information is recorded on the L1 layer, the recording sensitivity of the L1 layer above changes due to the change in the transmittance of the L0 layer. This is because of variations. However, since the optical disc has misalignment, eccentricity, and the like, when information is recorded from the same address in the L1 layer after information is recorded in the L0 layer, information is not recorded in the L0 layer. There arises a problem that information of the L1 layer is recorded. Therefore, in order to comply with the DVD standard, the address position of the L1 layer corresponding to the same address as the L0 layer is offset by about 105 μm to the inner peripheral side from the L0 layer to avoid problems due to bonding misalignment, eccentricity, and the like. .
JP 2000-31346 A Japanese Patent Laid-Open No. 2001-23237

  By the way, since DVD is recorded by CLV (Constant Linear Velocity: constant linear velocity), the inner peripheral side moves by a longer radius than the outer peripheral side as it advances the same address. Therefore, in order to reach the same address position on the L1 layer as the certain address position on the L0 layer, the L1 layer needs to go further to the inner circumference side than the L0 layer. If the address position is offset, the offset amount is about 260 μm on the inner circumference side, and there is room in the area for OPC (Optimum Power Control) and RMD (Recording Management Data) recording on the inner circumference side. There is no. Although a method in which the drive calculates the relationship between the address and the radius while referring to the data table can be considered, there is a problem that the operation becomes complicated.

  The present application has been made in consideration of the above circumstances, and an example of the problem is an optical recording medium that can reduce the deviation of the relative positional relationship on the inner peripheral side between a plurality of recording layers, and uses this An information recording apparatus and an information reproducing apparatus are provided.

In order to solve the above problems, a first recording layer for optically recording information, a second recording layer for optically recording the information by a light beam that has passed through the first recording layer, The information is recorded at a constant linear velocity in the first recording layer and the second recording layer, and addresses corresponding to each other in the first recording layer and the second recording layer. When the position is relatively offset so that the address position of the second recording layer is on the inner circumference side, the offset value over the entire radial direction is set to the track pitch in the recording track formed on the second recording layer. It is characterized by being narrowed within a range of 0.1 to 0.6% with respect to the track pitch in the recording track formed in the first recording layer so as to be 200 μm or less .

An information recording apparatus according to claim 3 is an information recording apparatus for optically recording information on the optical recording medium according to claim 1 or 2 , wherein a recording track formed on the first recording layer is provided. Irradiation means for irradiating one of the recording tracks formed on the second recording layer with the light beam, rotation driving means for rotating the optical recording medium at a predetermined speed, and the rotating optical recording medium And a recording control means for controlling recording by the light beam.

Furthermore, an information reproducing apparatus according to claim 4 is the information reproducing apparatus for optically reproducing information from the optical recording medium according to claim 1 or 2 , wherein the recording track formed on the first recording layer and the first Two irradiating means for irradiating one of the recording tracks formed on the recording layer with the light beam, rotation driving means for rotating the optical recording medium at a predetermined speed, and from the rotating optical recording medium And reproducing means for receiving reflected light of the light beam and reproducing information recorded on the optical recording medium.

  Hereinafter, an embodiment of an optical recording medium according to the present application will be described with reference to the drawings. In the following embodiment, a case where a dual-layer DVD-R is applied to an optical disc will be described.

(Embodiment of optical recording medium)
FIG. 1 is a sectional view showing an embodiment of the optical recording medium of the present application.

  As shown in FIG. 1, an optical disk 10 as an optical recording medium has a cover layer 11 and a first recording layer L0 on which a first recording track 12 for recording information is formed in order from the incident surface side of the laser beam LB. (The recording layer on the side close to the optical pickup), the second recording layer L1 on which the second recording track 14 for recording the recording information is formed via the intermediate layer 13 and the first recording layer L0 (the side far from the optical pickup) Recording layer) and a PC (polycarbonate) substrate 15 are laminated. At the time of recording / reproduction of the optical disc 10, depending on whether the condensing position of the laser beam LB irradiated from the lower side to the upper side is matched with the recording layer of the first recording layer L0 or the second recording layer L1 Recording / reproduction is performed on the first recording layer L0 or recording / reproduction is performed on the second recording layer L1.

  In the optical disc 10 of the present embodiment, the first recording layer L0 and the second recording layer L1 record information at a constant linear velocity, and the first recording layer L0 and the second recording layer are compliant with the DVD standard. This is an optical disc in which the address positions are offset between the first recording layer L0 and the second recording layer L1 based on the relative positional relationship between each address position and the radius of the layer L1. That is, in the optical disc 10, the address position of the second recording layer L1 corresponding to the same address position as the first recording layer L0 is relatively offset.

  Further, the optical disc 10 is such that the ratio (TP1 / TP2) of the track pitch TP2 in the second recording track 14 to the track pitch TP1 in the first recording track 12 exceeds 1. In other words, the optical disk 10 is such that the track pitch TP2 in the second recording track 14 is narrower than the track pitch TP1 in the first recording track 12 so that the offset value over the entire radial direction is within a predetermined range. Here, the track pitch is an interval in the radial direction of the first or second recording track 12, 14 of the optical disc 10 (the unit is, for example, (μm / track)). Further, the below-mentioned predetermined value is, for example, 200 μm or less as will be described later.

  Since the two-layer type optical disc 10 is configured as described above, when recording or reproducing the optical disc 10, the optical beam is emitted by an optical pickup 23 as an irradiation means of an information recording / reproducing apparatus described later. The laser beam LB is irradiated from the cover layer 11 side, that is, from the lower side to the upper side in FIG. 1, the focal length and the like are controlled, and the moving distance and direction in the radial direction of the optical disc 10 are controlled. Is done. Thereby, data is recorded on each recording layer, or recorded data is reproduced.

  As described above, in the optical disc 10 of the present embodiment, the first recording layer L0 and the second recording layer L1 are based on the relative positional relationship between the address positions and the radii of the first recording layer L0 and the second recording layer L1. An optical disk with the address position relatively offset, and the track pitch TP2 in the second recording track 14 is larger than the track pitch TP1 in the first recording track 12 so that the offset value in the entire radial direction is 200 μm or less. By narrowing, the shift of the relative positional relationship between the address and the radius of the first recording layer L0 and the second recording layer L1 can be reduced. As a result, it is possible to provide a margin for the OPC area and the RMD recording area.

(Example)
Next, based on FIG. 2 to FIG. 5, when the track pitch ratio TP1 / TP2 is not changed (TP ratio 1, indicated by a broken line) and when each% difference is indicated (shown by a solid line), the radius and An example in which the relative positional deviation between the first recording layer L0 and the second recording layer L1 is compared will be described.

  FIG. 2 shows a case where the offset amount at the position where the radius r is 24 mm is 200 μm and the track pitch ratio is 0.1%. According to FIG. 2, the track pitch ratio (TP1 / TP2) indicated by the broken line is not changed, and the track pitch ratio of the second recording layer L1 to the first recording layer L0 indicated by the solid line is narrowed by 0.1%. In comparison with the case, when the track pitch ratio is narrowed by 0.1%, the relative displacement on the inner peripheral side is as low as 200 μm, and the address and radius of the first recording layer L0 and the second recording layer L1 are reduced. It can be seen that the relative positional deviation can be reduced. Here, the above-mentioned offset amount of 200 μm means that the address position of the second recording layer L1 corresponding to the same address as the first recording layer L0 is offset by 200 μm from the first recording layer L0 to the inner peripheral side.

  FIG. 3 shows a case where the offset amount at the position where the radius r is 24 mm is 116 μm and the track pitch ratio is 0.28%. According to FIG. 3, the track pitch ratio (TP1 / TP2) indicated by the broken line is not changed, and the track pitch ratio of the second recording layer L1 to the first recording layer L0 indicated by the solid line is narrowed by 0.28%. As compared with the case, when the track pitch ratio is narrowed by 0.28%, the relative displacement is remarkably reduced on both the inner and outer peripheral sides, and the first recording layer L0 and the second recording layer L1 are reduced. It can be seen that the relative positional deviation between the address and the radius can be extremely small.

  FIG. 4 shows a case where the offset amount at the position where the radius r is 24 mm is 105 μm, and the track pitch ratio is different by 0.5%. According to FIG. 4, the track pitch ratio (TP1 / TP2) indicated by the broken line is not changed, and the track pitch ratio of the second recording layer L1 to the first recording layer L0 indicated by the solid line is narrowed by 0.5%. In comparison with the case, when the track pitch ratio is reduced by 0.5%, the relative displacement on the outer peripheral side slightly increases, but the relative displacement on the inner peripheral side becomes lower, and the first recording layer L0 and the first recording layer L0. It can be seen that the deviation in the relative positional relationship between the address and the radius of the two recording layers L1 can be reduced. In this case, substantially the same result was obtained even when the track pitch ratio was reduced by 0.6%.

  FIG. 5 shows a case where the offset amount at the position where the radius r is 24 mm is 105 μm and the track pitch ratio is different by 1%. According to FIG. 5, when the track pitch ratio (TP1 / TP2) indicated by the broken line is not changed, and when the track pitch ratio of the second recording layer L1 to the first recording layer L0 indicated by the solid line is reduced by 1%. When the track pitch ratio is narrowed by 1%, the relative displacement increases to about 280 μm on the outer peripheral side, and the relative positional relationship between the address and the radius of the first recording layer L0 and the second recording layer L1 is shifted. It became clear that it was not possible to make it smaller.

  According to the embodiment as described above, the first recording layer L0 and the second recording layer L1 record information at a constant linear velocity, and the second recording layer L1 corresponding to the same address as the first recording layer L0. The address position is offset in the range of 105 to 116 μm on the inner peripheral side from the first recording layer L0, and the track pitch TP2 in the second recording layer L1 is set to 0.1 to 0 with respect to the track pitch TP1 in the first recording layer L0. If it is made narrow within the range of .6%, it is possible to reduce the deviation of the relative positional relationship between the address and the radius of the first recording layer L0 and the second recording layer L1. In particular, when the offset amount is 116 μm and the track pitch ratio of the second recording layer L1 to the first recording layer L0 is narrowed by 0.28%, the address and radius of the first recording layer L0 and the second recording layer L1. It has been found that the deviation of the relative positional relationship with can be made extremely small.

  Note that when the ratio of the track pitch TP2 in the second recording layer L1 to the track pitch TP1 in the first recording layer L0 is narrowed by less than 0.1, as in the case where the track pitch ratio is not changed, on the inner peripheral side. The relative displacement of the first recording layer L0 increases beyond 200 μm, and the deviation of the relative positional relationship between the address and the radius of the first recording layer L0 and the second recording layer L1 cannot be reduced.

  Further, when the ratio of the track pitch TP2 in the second recording layer L1 to the track pitch TP1 in the first recording layer L0 is made narrower than 0.6, the ratio of the track pitch is not changed. On the contrary, the relative displacement on the outer peripheral side increases to 280 μm or more, and the deviation of the relative positional relationship between the address and the radius of the first recording layer L0 and the second recording layer L1 cannot be reduced.

(Example of application to information recording / reproducing device)
Next, the case where information recording / reproduction is performed on the optical recording medium configured as described above using the information recording / reproducing apparatus 20 shown in FIG. 6 will be described. That is, the information recording / reproducing apparatus 20 is an apparatus that records information on the optical disc 10 and reads information recorded on the optical disc 10 under the control of the controller 24.

  As shown in FIG. 6, in the information recording / reproducing apparatus 20, the optical disk 10 is rotated at a predetermined speed by a spindle motor 21 serving as a rotation driving means. The spindle motor 21 is driven by a rotation control unit 22 to be described later, and rotates the optical disc 10 at a predetermined rotation speed.

  The optical disk 10 is irradiated with a laser beam LB whose amount of light is controlled from the optical pickup 23 of the information recording / reproducing apparatus 20. The laser beam LB reflected by the optical disk 10 is applied to a light detection unit (not shown) of the optical pickup 23. This light detection unit is configured by using a split light detector or the like, and generates a focus error signal, a tracking error signal, and a reproduction signal during reproduction from the reflected light of the laser beam LB described above by photoelectric conversion and current-voltage conversion. Generate. The focus error signal, tracking error signal, and reproduction signal are supplied to a controller 24 that controls the entire information recording / reproducing apparatus 20. The reproduction signal is also supplied to the reproduction signal processing circuit 25, where the signal is reproduced.

  The controller 24 generates a tracking control signal for controlling an objective lens (not shown) of the optical pickup 23 based on the supplied tracking error signal and supplies the tracking control signal to the tracking servo 26.

  The tracking servo 26 drives the objective lens of the optical pickup 23 according to the supplied tracking control signal, so that the laser beam LB is irradiated along the first recording track 12 or the second recording track 14.

  Further, the controller 24 controls the objective lens of the optical pickup 23 based on the focus error signal so that the focal position of the laser beam LB becomes a desired position of the first recording layer L0 or the second recording layer L1. A focus control signal is generated and supplied to the focus servo 27.

  Based on the address information recorded in the pre-pits read from the tracking error signal, the controller 24 moves the focal position of the laser beam LB from the first recording layer L0 to the second recording layer L1 or from the second recording layer L1. A focus control signal for controlling the objective lens of the optical pickup 23 is generated and output to the focus servo 27 so as to be one recording layer L0.

  The focus servo 27 is controlled so that the focal position of the laser beam LB becomes a desired position of the recording layer L0 or L1 by driving the objective lens of the optical pickup 23 in accordance with the output focus control signal. Is done.

  Further, the controller 24 generates a rotation control signal for controlling the spindle motor 21 and outputs the rotation control signal to the rotation control unit 22. The rotation control unit 22 drives the spindle motor 21 according to the output rotation control signal, whereby the rotation speed of the optical disc 10 is controlled to a predetermined rotation speed.

  In addition, this application is not limited to the said embodiment, A various change is possible. For example, the optical disc 10 of the present application is not limited to two-layer single-sided, that is, dual layer, but may be double-sided, that is, dual-layer double side. Further, as described above, the optical disk is not limited to an optical disk having two recording layers, and may be a multilayer optical disk having three or more layers. In the case of three or more layers, a track pitch ratio corresponding to the offset amount of each layer is set. As a result, the applicable range for the optical disc of the present application can be expanded. The present invention can also be applied to a large-capacity recording medium such as a disk using a blue laser for recording and reproduction.

It is a section lineblock diagram showing one embodiment of an optical recording medium of this application. It is a graph which shows the shift | offset | difference of the relative positional relationship of a 1st recording layer and a 2nd recording layer in track pitch ratio and a radius. It is a graph which shows the shift | offset | difference of the relative positional relationship of a 1st recording layer and a 2nd recording layer in track pitch ratio and a radius. It is a graph which shows the shift | offset | difference of the relative positional relationship of a 1st recording layer and a 2nd recording layer in track pitch ratio and a radius. It is a graph which shows the shift | offset | difference of the relative positional relationship of a 1st recording layer and a 2nd recording layer in track pitch ratio and a radius. It is a block diagram which shows the information recording / reproducing apparatus to which this application is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Optical disk 12: 1st recording track 13: Intermediate | middle layer 14: 2nd recording track 15: PC board | substrate 20: Information recording / reproducing apparatus 21: Spindle motor 22: Rotation control part 23: Optical pick-up 24: Controller L0: 1st recording Layer L1: Second recording layer TP1: Track pitch TP2: Track pitch

Claims (4)

An optical recording medium comprising at least a first recording layer for optically recording information and a second recording layer for optically recording the information by a light beam that has passed through the first recording layer ,
In the first recording layer and the second recording layer, the information is recorded at a constant linear velocity, and the address positions corresponding to each other in the first recording layer and the second recording layer are the addresses of the second recording layer. When the relative offset is made so that the position is on the inner circumference side,
The track pitch in the recording track formed in the second recording layer is 0.1 relative to the track pitch in the recording track formed in the first recording layer so that the offset value in the entire radial direction is 200 μm or less. An optical recording medium characterized by being narrowed within a range of ˜0.6% . The optical recording medium according to claim 1,
When the address position of the second recording layer corresponding to the same address as the first recording layer is offset in the range of 105 to 116 μm to the inner peripheral side from the first recording layer,
An optical recording medium , wherein the track pitch in the second recording layer is narrowed by 0.28% with respect to the track pitch in the first recording layer . In the information recording apparatus which records information optically with respect to the optical recording medium of Claim 1 or 2,
  Irradiating means for irradiating the light beam to any one of a recording track formed on the first recording layer and a recording track formed on the second recording layer;
  Rotation driving means for rotating the optical recording medium at a predetermined speed;
  Recording control means for controlling recording by the light beam on the rotating optical recording medium;
  An information recording apparatus comprising: In the information reproducing | regenerating apparatus which reproduces | regenerates information optically from the optical recording medium of Claim 1 or 2,
  Irradiating means for irradiating the light beam to any one of a recording track formed on the first recording layer and a recording track formed on the second recording layer;
  Rotation driving means for rotating the optical recording medium at a predetermined speed;
  Reproducing means for receiving reflected light of the light beam from the rotating optical recording medium and reproducing information recorded on the optical recording medium;
  An information reproducing apparatus comprising:

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