JP2011175734A - Multilayer recording type optical disk, and recording method and recording device for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow random access in a multilayer optical disk and a recording method, and to record data by optimal recording power when it is expected that recorded and unrecorded places randomly occur in an upper layer of a recording layer. <P>SOLUTION: Each layer includes a data recording area and a trial writing area divided into a plurality of small areas. In the small area of the trial writing area, data is recorded beforehand to allow combination of recording and unrecording in other each layer with respect to the small area for executing OPC of an OPC-executing layer, and OPC is executed for each small area where a combination of recording and unrecording of other each layer is different. The data recording area is divided for each of the plurality of small areas, and information on a combination of recording and unrecording states of each layer is recorded in a disk for each area. During recording of user data, according to this information, a result of OPC under a condition where recording and unrecording states of each layer match is set as optimal power. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a multilayer recording type optical disc, and more particularly to a method for obtaining an optimum value of laser power for recording on a multilayer recording type optical disc.

  When recording information on an optical disk having a multi-layer structure that can be additionally written or rewritten, a method of adjusting the laser output during recording to an optimum recording power value for the data area of the layer in which information is written (Optimum Power Control, hereinafter “ The method of Patent Document 1 is known as “OPC”).

JP 2000-31346 A

  When recording information by irradiating a multilayer recording type optical disc with laser light, the upper layer transmittance near the laser light incident surface differs depending on whether the upper layer is recorded or unrecorded, Even when laser light having the same power is emitted, the power of the laser light applied to the lower layer far from the incident surface is different. Also, the optimum recording power may fluctuate due to the influence of crosstalk from information recorded on other recording layers.

  In Patent Document 1, OPC is performed in a “lower layer test writing region” with a laser beam that has passed through a “higher layer test writing region” on which a random pattern has been recorded. However, the “optimal recording power value” obtained in this way is not suitable for recording in the “lower layer data area” with laser light that has passed through the unrecorded “upper layer data area”. Absent.

  In recent years, optical discs capable of recording data on an arbitrary layer of a multilayer recording type optical disc have appeared. In such an upper layer data area of the optical disc, there are cases where an area where data is recorded and an area where data is not recorded are mixed. For this reason, when recording data in the lower layer, there is a case where data is recorded in the “lower layer data area” with a laser beam that has passed through an unrecorded “upper layer data area” and a recorded “upper layer data area”. May be recorded in the “lower-layer data area” with the laser beam that has passed “ However, since the “optimal recording power value” obtained by OPC in Patent Document 1 is an optimum value for one, it is not effective for the other, and does not contribute to an improvement in data recording quality in any situation. There was a problem.

  The above problems are solved by the invention described in the claims.

  Even if recording is performed randomly on a multi-layer disc, even if the recorded and unrecorded locations of each layer are randomly distributed and the transmittance varies, writing can be performed with good power, and the data recording quality can be improved. Can be improved.

The figure which shows the 1st Example which is the multilayer recording type optical disk of this invention. The figure which shows the 2nd Example which is the recording method of the multilayer recording type optical disk of this invention. The figure which shows the 3rd Example which is the recording method of the multilayer recording type optical disk of this invention. The figure which shows the 4th Example which is the recording method of the multilayer recording type optical disk of this invention. The figure which shows the 5th Example which is the recording device of the multilayer recording type optical disk of this invention. The figure which shows an example of the recorded / unrecorded information area of a 1st Example.

  With reference to FIG. 1, a multi-layer recording optical disk according to the first embodiment of the present invention will be described by taking a four-layer recording optical disk as an example.

  FIG. 1 is a cross-sectional view of a multi-layer recording optical disc that can be recorded or reproduced from one side, with the right side being the inner peripheral side of the optical disc and the left side being the outer peripheral side of the optical disc. Laser light for recording or reproducing each layer of the optical disc is incident from above. Hereinafter, the layers are referred to as a first layer, a second layer, a third layer, and a fourth layer in order from the laser light incident surface.

  Each layer has, as a recordable area, a test writing area PCA (Power Calibration Area) for obtaining an optimum power by performing OPC, and a data recording area for writing user data. In other words, in FIG. 1, there are four PCAs: the first layer PCA, the second layer PCA, the third layer PCA, and the fourth layer PCA. The PCA of each layer is subdivided into a plurality of small regions (areas) in the radial direction such as a, b, c, d, e, f, g, h,. In this embodiment, the PCA of each layer is described as being provided in a spiral shape, but the PCA may be provided in a concentric shape.

  As shown in FIG. 1, the areas a to h of the fourth layer PCA are all unrecorded, but the first layer PCA, the second layer PCA, and the third layer PCA are as shown in Table 1. A random pattern is recorded in

  By recording a random pattern from the first layer to the third layer PCA according to Table 1, all combinations of recorded / unrecorded from the first layer PCA to the third layer PCA can be prepared.

  If OPC is performed on eight areas a to h of the fourth layer PCA, the first layer to the third layer generated when recording the data recording area of the fourth layer of the optical disc that allows random recording. It is possible to know the optimum value of the recording power for all combinations of recorded / unrecorded.

  On the other hand, the data recording area is divided into a plurality of areas A, B, C, D, E, and F, and information indicating the recorded / unrecorded combination state for each layer of each area is stored in area A of the first layer. Record (recorded / unrecorded information recording area). In this example, information indicating the recorded / unrecorded combination state of each layer in each area is recorded in area A of the data recording area of the first layer. This information may be recorded in any area.

  When user data is recorded in the data recording area of the fourth layer, the optimum recording power obtained in the same combination as the information indicated by the recorded / unrecorded information recording areas of the first to third layers of the area scheduled to be recorded Recording in a predetermined area facilitates recording with an appropriate recording power.

  Similarly, eight areas corresponding to the recorded / unrecorded combinations of the second to fourth layers are prepared in the first layer PCA, and the first, third, and second layers are prepared in the second layer PCA. Eight areas corresponding to the recorded / unrecorded combinations of the four layers are prepared, and the eight areas corresponding to the recorded / unrecorded combinations of the first layer, the second layer, and the fourth layer are prepared in the PCA of the third layer. Is prepared, and all recorded / unrecorded combinations of other layers can be prepared for any of the first to third layers by appropriately arranging recorded / unrecorded in each area. .

As described above, if PCA is subdivided into 32 areas (4 × 2 ^4-1 ), recorded / unrecorded of the other three recording layers that may occur when recording an arbitrary recording layer of a four-layer recording type optical disc. An optical disc with all combinations of recordings can be provided. If this is generalized, it is understood that an m × 2 ^m-1 area should be prepared in the case of an m-layer optical disc. As described above, in the case of an m-layer optical disc, if OPC is performed on the prepared m × 2 ^m-1 area, the mth layer data recording area of the optical disc that allows random recording is recorded. It is possible to know the optimum value of the recording power in all the combinations of recorded / unrecorded except the m layer. When user data is recorded in the data recording area of the m-th layer, it is the same combination as the information indicating the recorded / unrecorded state recorded in the recorded / unrecorded information recording area corresponding to the recording scheduled area. Recording in a predetermined area with the obtained optimum recording power makes it easy to perform recording with an appropriate recording power.

  In the above, since the recorded / unrecorded combination of the lower recording layer far from the incident surface of the laser beam was taken into consideration, the PCA was subdivided into 32 areas. However, since the influence of the crosstalk from the lower recording layer on the recording of the upper recording layer is small, the PCA may be subdivided considering only the recorded / unrecorded state of the upper recording layer. That is, 2 areas considering the first layer for the second layer, 4 areas considering the first to second layers for the third layer, and 8 considering the first to third layers for the fourth layer A total of 14 areas may be prepared, and recorded / unrecorded information may be appropriately arranged in each area.

  In this way, if OPC is performed on each area of the PCA subdivided into 14 areas, all recorded / unrecorded upper layers that can occur when recording an arbitrary recording layer of a four-layer recording type optical disc are recorded. It is possible to know the optimum value of the recording power of the combination. Recorded / unrecorded information corresponding to the area scheduled to be recorded on each layer Recorded / unrecorded information The information indicating the recorded / unrecorded status and the upper layer are recorded in the specified area with the optimum recording power obtained in the same combination. Recording makes it easy to perform recording with an appropriate recording power.

  In the above description, an optical disk having a four-layer structure has been described as an example. However, the application target of the present invention is not limited to this, and the present invention can be applied to an optical disk having an arbitrary number of recording layers. .

For example, when the total number of recording layers is m, if each PCA from the first layer to the (m−1) th layer is subdivided into 2 ^m−1 , the upper layer that can occur during the mth layer recording. All recorded / unrecorded combinations from the first layer to the (m−1) th layer can be prepared. Further, if the PCA of each layer from the first layer to the (m−2) th layer is subdivided into 2 ^m−2 , the upper first layer to the second layer can be generated at the time of recording the (m−1) th layer. All combinations of recorded / unrecorded up to the (m-2) layer can be prepared. Similarly, it is possible to be subdivided PCA of the first layer to 2 ^1, it can occur during the recording of the second layer of the upper, providing all combinations of the recorded / unrecorded.

That is, when the number of recording layers is m, if the PCA of each layer is subdivided into 2 ^m−1 +2 ^m−2 +... +2 ² +2 ¹ , All combinations of recorded / unrecorded recording layers can be prepared in advance.

As described above, if OPC is performed on each area of the PCA subdivided into 2 ^m−1 +2 ^m−2 +... +2 ² +2 ¹ areas, an arbitrary recording layer of an m-layer recording type optical disc is recorded. It is possible to know the optimum value of the recording power of all combinations of recorded / unrecorded upper layers that can occur when the recording is performed. Recorded / unrecorded information corresponding to the area scheduled to be recorded on each layer Recorded / unrecorded information The information indicating the recorded / unrecorded status and the upper layer are recorded in the specified area with the optimum recording power obtained in the same combination. Recording makes it easy to perform recording with an appropriate recording power.

  In this embodiment, the recorded / unrecorded information recording area is a part of the data recording area, but there is no difference in effect even if the data recording area and the area independent of the PCA are used.

  The unit for dividing the data recording area is the unit in which a plurality of ECC blocks or ECC blocks are collected for a DVD, and the unit for recording and reproduction is a unit for collecting a plurality of Physical Clusters or Physical Clusters in a Blu-ray Disc. Therefore, it is preferable.

  FIG. 2 is a flowchart showing a second embodiment which is a recording method of the multilayer recording type optical disk described as the first embodiment.

  Step 201 aligns the pick with the nth area of the mth layer PCA. In the first embodiment, the pick position is first aligned with the area a.

  Step 202 is execution of OPC. More specifically, recording is performed by sequentially changing the recording power, the recorded area is reproduced, and the recording power with the best reproduction quality is selected as the optimum recording power. The reproduction quality is determined using an error rate, jitter, waveform, etc. (for example, β).

  In step 203, the result of OPC in the nth area is stored as the optimum recording power.

  Step 204 performs n = n + 1 to change the area. That is, when combined with step 201, the area is changed sequentially. When step 201 and step 204 are combined, in the first embodiment, the pick position is changed in the order of areas a, b, c.

  Step 205 determines whether or not OPC has been executed for all combinations for the m-th layer. If not completed, the process returns to step 201 and continues. If completed, the process proceeds to the next step 206. In the first embodiment, it is determined whether the OPC has been executed in all the areas a, b, c, d, e, f, g, and h.

  Step 206 performs m = m + 1 to change the layer on which OPC is performed. In step 207, it is determined whether the OPC of all layers has been completed. If not completed, steps 201 to 206 are repeated. If completed, go to the next step 208.

  Step 208 is a process of waiting for a command for recording user data in the data recording area.

  When a user data recording command is issued, in step 209, recorded / unrecorded information at a recording scheduled position is read by the recording command. In the first embodiment, the recorded / unrecorded information of the other layer is read from the recorded / unrecorded information recording area of the disc.

  The optimum recording power obtained as a result of performing the OPC with the same combination as the recorded / unrecorded combination of the other layer based on the recorded / unrecorded information read in Step 210 is set as the recording power.

  Predetermined data is written with the recording power set in step 211.

  As described above, according to the present embodiment, an optimum recording power can be obtained even when random access including interlayers is permitted in a multilayer recording type optical disc. Specifically, by performing OPC in this way, it is possible to obtain an appropriate laser power for all combinations that can occur when recording on a desired recording layer, and when randomly recording on any recording layer Even so, it is possible to perform recording using an appropriate laser power by using information on the recording state of the recorded / unrecorded information recording area from the laser power obtained by each OPC.

  In this embodiment, the PCA for the m-th layer is provided with all the combination areas where other layers are recorded and unrecorded, and the OPC is performed for all of them. From the viewpoint of transmittance, the m-th layer A combination area selected for all recorded and unrecorded combinations in the upper layer is provided for the PCA for OPC and OPC is performed. Results may be selected. In this embodiment, the optimum power is adjusted in step 202 for each combination. However, the recording waveform may be further adjusted.

  FIG. 3 is a flowchart showing a third embodiment which is a recording method of the multilayer recording type optical disk described as the first embodiment. In FIG. 3, step 201 to step 211 are the same as those in the third embodiment, and the description thereof will be omitted.

  Step 301 updates the recorded / unrecorded information in the recorded / unrecorded information recording area of the disc in the first embodiment, reflecting the data write in Step 211.

  As described above, according to the present embodiment, the optimum recording power can be obtained even when random access including the interlayer is permitted in the multilayer recording optical disk. In addition, every time user data is recorded in the data area, the recorded / unrecorded information in the recorded / unrecorded information recording area of the disc in the first embodiment is updated, so that the data is randomly included including the layers. Even if a light is added, the optimum recording power can be obtained each time. In this embodiment, the optimum power is adjusted in step 202 for each combination. However, the recording waveform may be further adjusted.

  FIG. 4 is a flowchart showing a fourth embodiment which is a recording method of the multilayer recording type optical disk described as the first embodiment. This embodiment embodies user data write processing. In FIG. 4, step 201 to step 208 are the same as those in the fourth embodiment, and a description thereof will be omitted. In step 401, the pickup comes to the head of the area which is a unit indicating the recorded / unrecorded state in the recorded / unrecorded information of the recorded / unrecorded information recording area of the disc in the first embodiment. It is to determine whether or not. If it is determined in step 401 that the pickup is at the head of the area, data writing to the disk is started in step 402. In step 403, it is determined whether the rear end of the area has been reached. If it is determined at step 403 that it is the rear end of the area, data writing to the disk is terminated at step 404. In step 301, as in the third embodiment, the data write in steps 401 to 404 is reflected, and the recorded / unrecorded information recording area of the disc in the first embodiment is recorded. Update information.

  As described above, according to the present embodiment, the user data is written to the data area in the recorded / unrecorded information recording area of the disc as recorded in the first embodiment. Since it is performed for each area, which is a unit indicating the state, it is possible to easily select an OPC result corresponding to recorded / unrecorded information in area units. In this embodiment, the recording is finished every time the rear end of the area is detected. However, when the capacity to be recorded is larger than the capacity of the area, the writing is continued until the rear end of the next area. It doesn't matter.

  FIG. 5 is a block diagram showing a fifth embodiment which is a recording apparatus for a multilayer recording type optical disk according to the present invention.

  In FIG. 5, 501 is an optical disk, 502 is a disk motor that rotates the optical disk 501, 503 is a laser that emits light for reading and writing of the optical disk 501, 504 is equipped with a laser 503, and a lens for focusing the laser light on the optical disk. The optical pickup 505 further includes an OEIC that converts an optical signal into an electric signal. A signal reproduction processing circuit 505 performs waveform equalization on the signal detected by the optical pickup 504 to reproduce a synchronous clock. Furthermore, jitter at each edge is detected.

  Reference numeral 506 denotes a test writing reproduction signal processing circuit, which derives the optimum recording power for each small area of the PCA, the processing shown in step 202 of the second embodiment, based on the jitter detected by the signal reproduction processing circuit 505. An optimum power storage circuit 507 stores the optimum recording power for each small area derived by the trial writing reproduction signal processing circuit 506. Reference numeral 508 denotes a decoder that performs demodulation processing and error correction processing in accordance with the format of data recorded on the disk. Reference numeral 509 denotes a circuit for detecting data relating to the recording state of each layer decoded by the decoder 508 in the recorded / unrecorded information recording area of the disc in the first embodiment. 515 is an optimum for selecting the optimum recording power obtained from the optimum recording power stored in the optimum recording power storage circuit 507 under the same condition as the recorded / unrecorded recording state of each layer at the scheduled recording location detected from 509. It is a power selection circuit.

  A servo control circuit 510 controls the rotation of the disk motor and the focus and tracking of the light beam. Reference numeral 511 denotes a laser beam control circuit that controls the emission intensity of the laser 503. Reference numeral 512 denotes a test writing recording signal processing circuit, which generates a signal pattern for performing test writing on the PCA. In this embodiment, a random pattern is generated as an example. In this embodiment, the test write recording signal processing circuit 512 is provided inside the test write processing circuit 516 together with the test write reproduction signal processing circuit 506. A recording signal processing circuit 513 performs error correction code addition and modulation processing when writing user data in the data recording area. Reference numeral 514 denotes a CPU which controls the signal reproduction processing circuit 505, the trial writing reproduction signal processing circuit 506, the servo control circuit 510, the laser beam control circuit 511, the trial writing recording signal processing circuit 512, and the recording signal processing circuit 513, and is optimal. The output of the power selection circuit 515 is used for control of the laser beam control circuit 511.

  The operation when the recording apparatus of this embodiment performs recording on the optical disk of the first embodiment by the recording method of the second embodiment will be described below.

  First, in response to step 201 of the second embodiment, the pick is moved to the area a of the mth layer under the control of the servo control circuit 510.

  Next, corresponding to step 202, two processes of writing and reading are performed. First, in the write process, a random pattern generated by the test writing recording signal processing circuit 511 is recorded in this area while the laser beam control circuit 511 sequentially changes the light emission power of the laser 503. In the next read process, the signal reproduction processing circuit 505 detects jitter for each emission power from the signal detected by reproducing the recorded signal with the optical pickup 504. The test writing reproduction signal processing circuit 506 sets the light emission power that minimizes the jitter as the optimum recording power, and stores the result in the optimum power storage circuit 507. Control returning from step 203 to step 201 via step 204 is realized by the servo control circuit 509 moving the pick sequentially to the areas b, c, d,... Of the first embodiment.

  Corresponding to step 205, when the CPU 514 determines that the OPC for all the combinations has been completed, that is, when the OPC in the areas a to h is completed, the OPC process for other layers is performed corresponding to step 206. In step 207, the processing is repeated until it is determined that OPC for all layers has been completed.

  When a data recording command is issued by the CPU 514 after all layers of OPC are completed, the signal reproduction processing circuit 505 reproduces the data and the synchronous clock, and the decoder 508 performs decoding according to the format. From the reproduced data, the recording state detection circuit 509 performs processing 209 for detecting recorded / unrecorded information in the recorded / unrecorded information recording area of the disc as in the first embodiment. The optimum power selection circuit selects the result of the OPC performed under the condition matching the recorded / unrecorded information of each layer at the scheduled recording location detected by 509 from the optimum power stored in 507. The selected optimum recording power is sent to the CPU 514, and the CPU 514 controls the laser beam control circuit 511 based on the optimum power.

  As described above, according to the present embodiment, it is possible to provide a recording apparatus capable of obtaining an optimum recording power in each layer with respect to a multilayer recording optical disc that permits random access including the layers.

  In the present embodiment, the case where the evaluation of the reproduction quality of the trially written signal is performed using jitter. However, when the waveform information such as β is used, β is detected by the signal reproduction processing circuit 505. The test writing reproduction signal processing circuit 506 sets the light emission power that gives the target β value as the optimum recording power. In this embodiment, the optimum power is adjusted, but the recording waveform may be further adjusted. In this case, the recording waveform is controlled by the laser beam control circuit 511.

  FIG. 6 is a diagram showing an example of the multilayer recording type optical disc of the first embodiment and a table recorded in the recorded / unrecorded information area.

  (A) is a recording type optical disc having a four-layer structure according to the first embodiment, in which the first layer 4 area C, the second layer area B and the area C of the data recording area have been recorded, The case where it is not recorded is shown. The table at this time is shown in (b). In the first layer, area A and area C are recorded, and the others are unrecorded. The area A is recorded because the area A is assigned to the recorded / unrecorded information area, and therefore data consisting of this table is recorded. In the second layer, as shown in (a), areas B and C are recorded, and the others are unrecorded. As shown in (a) of the third layer, all areas are unrecorded. In the fourth layer, as shown in (a), all areas are unrecorded. With such a table, the recorded / unrecorded state of each area and each layer can be shown.

  501 ... Optical disk, 502 ... Disk motor, 503 ... Laser, 504 ... Optical pickup, 505 ... Signal reproduction processing circuit, 506 ... Trial writing reproduction signal processing circuit, 507 ... Optimal power storage circuit, 508 ... Decoder, 509 ... Recording state detection Circuit 511 ... Laser beam control circuit 512 ... Test writing recording signal processing circuit 513 ... Recording signal processing circuit 515 ... Optimum power selection circuit

Claims (6)

A multilayer recording type optical disc having m recording layers (m is an integer of 2 or more) having a test writing area and a data recording area,
The test writing area of each layer provided in a spiral shape is divided from the first small area to the nth small area (n is an integer of 2 or more) from the inner periphery to the outer periphery of the optical disc.
For an unrecorded small area of a predetermined recording layer, a combination of recorded / unrecorded data in (m−1) small areas at the same radial position of another recording layer is the (m− 1) Unlike the combination of recorded / unrecorded data in a small area,
A multilayer recording type optical disc, further comprising an area for recording information indicating a recorded / unrecorded combination state of each layer at each position of the data recording area. A multilayer recording type optical disc having m recording layers (m is an integer of 2 or more) having a test writing area and a data recording area,
The test writing area of each layer provided in a spiral shape is divided from the first small area to the nth small area (n is an integer of 2 or more) from the inner periphery to the outer periphery of the optical disc.
For an unrecorded small area of a predetermined recording layer, a combination of recorded / unrecorded data in (m−1) small areas at the same radial position of another recording layer is the (m− 1) Unlike the combination of recorded / unrecorded data in a small area,
The data recording area is further divided into a plurality of groups at the same position when viewed from the top, and further includes an area for recording information indicating a recorded / unrecorded combination state of each layer in each divided area Multi-layer recording type optical disc. The recording layer having a test writing area and a data recording area is provided with m recording layers (m is an integer of 2 or more), and the test writing area of each layer provided in a spiral shape is a first small area from the inner periphery to the outer periphery of the optical disc. Are divided into n-th small areas (n is an integer equal to or greater than 2), and (m−1) small areas at the same radial position of other recording layers are compared with unrecorded small areas of a predetermined recording layer. The multi-layer recording type optical disc has a combination of recorded / unrecorded data and an optical disc having a trial write area different from the recorded / unrecorded combination of data in (m-1) small areas at other radial positions. A recording method,
A process of performing test writing in a test writing area of a predetermined recording layer and obtaining each optimum recording power in each small area in the test writing area;
A recording method for a multi-layer recording type optical disk, characterized in that, when performing data recording, a recording process is performed with an optimum recording power obtained under the same conditions as the combination of recorded / unrecorded in other recording layers. The recording layer having a test writing area and a data recording area is provided with m recording layers (m is an integer of 2 or more), and the test writing area of each layer provided in a spiral shape is a first small area from the inner periphery to the outer periphery of the optical disc. Are divided into n-th small areas (n is an integer equal to or greater than 2), and (m−1) small areas at the same radial position of other recording layers are compared with unrecorded small areas of a predetermined recording layer. The recorded / unrecorded combination of data includes a trial writing area different from the recorded / unrecorded combination of data in the (m−1) small areas at other radial positions,
An optical disc further comprising an area for recording information indicating a recorded / unrecorded combination state of each layer in each divided area by dividing the data recording area from the upper surface into the same group at the same position. A recording method for a multilayer recording type optical disc,
A process of performing test writing in a test writing area of a predetermined recording layer and obtaining each optimum recording power in each small area in the test writing area;
When performing data recording, a process of reading information indicating the recorded / unrecorded combination status of each layer at a recording scheduled location, information indicating the recorded / unrecorded combination status, and recorded information of other recording layers / The process of recording the unrecorded combination with the optimum recording power obtained under the same conditions,
A recording method for a multi-layer recording type optical disc, comprising: a process of updating information indicating a recorded / unrecorded combination state of each layer of the data recording area after the data recording process.   5. The recording method for a multi-layer recording type optical disk according to claim 4, wherein the user data is written to the data recording area in the divided areas. The recording layer having a test writing area and a data recording area is provided with m recording layers (m is an integer of 2 or more), and the test writing area of each layer provided in a spiral shape is a first small area from the inner periphery to the outer periphery of the optical disc. Are divided into n-th small areas (n is an integer equal to or greater than 2), and (m−1) small areas at the same radial position of other recording layers are compared with unrecorded small areas of a predetermined recording layer. The recorded / unrecorded combination of data is different from the recorded / unrecorded combination of data in the (m−1) small areas at other radial positions, and the recorded data of each layer at each position in the data recording area A recording device for a multi-layer recording optical disc further comprising an area for recording information indicating a state of an unrecorded combination,
A laser for irradiating the optical disc with a laser beam;
A laser beam control circuit for controlling the laser;
A test writing process circuit that performs test writing in a test writing area of a predetermined recording layer and obtains each optimum recording power in each small area in the test writing area;
An optimum recording power selection means for selecting an optimum recording power at a recording scheduled position of the layer in accordance with information indicating a recorded / unrecorded combination state of each layer from each obtained optimum recording power;
A recording apparatus for a multilayer recording type optical disc, comprising:

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