JP2006099889A - Optimal power recording method in optical disk memory device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize the precision laser power, when performing disk-at-once recording by setting up a test recording area close to the recording position. <P>SOLUTION: This method calculates the amount of data to record before starting, to record and finds the area not to use to record from the calculated results and the recordable capacity of the disk, when performing disk-at-once recording, then decides to use this area for making test writing to optimize the recording laser power. In this configuration, test writing becomes possible, in the location close to the actual recoding area by utilizing the wasteful area caused by disk at once recording, and optimum laser power can be found accurately. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a method for recording data on an optical disc with laser light.

When recording information on a recordable optical disk such as a DVD, if the irradiation energy of the laser beam applied to the recording layer is too large or too small, the shape and edge of the formed recording mark are distorted, and the recorded data The reproduction characteristics of are deteriorated. Therefore, when recording data, it is necessary to set the power of the laser beam to a value suitable for writing. However, laser diodes that output laser light have the property that the wavelength variation is very large due to temperature changes. In addition, the sensitivity characteristics of the recording layer also vary from one optical disc to another. In order to solve this problem, OPC (Optimum Power Control Optimum Power Control) technology has been conventionally used. In this technology, a test writing area PCA (Power Calibration Area) for adjusting recording power is provided on a disk, and test data is written on the test writing area at the time of data recording. The actual data is recorded after obtaining the recording power with which sufficient data reproduction characteristics can be obtained based on the result of reading the data.

FIG. 3 shows the configuration of an optical disc apparatus that performs recording / reproduction using a single pickup. The encoder 5 converts information to be written into an EFM (Eight to Fourteen Modulation) signal and outputs it to the recording control circuit 4. The recording control circuit 4 inputs an EFM signal from the encoder 5, a control signal from the CPU 6, and a control signal from the servo circuit 7, and outputs a drive control signal to the laser drive circuit 3. The laser drive circuit 3 supplies power to the laser diode in the optical pickup 1 based on the drive control signal from the recording control circuit 4 and causes the optical disc 2 to emit laser light. The servo circuit 7 controls the position of the optical pickup 1.

The RF amplifier circuit 10 outputs an RF signal obtained by amplifying the reflected light from the optical disk 1 received by the optical pickup 1 during the reproduction operation to the jitter detection circuit 8 and the β detection circuit 9. The β detection circuit 9 measures the peak value of the input RF signal, that is, the maximum value A and the minimum value B, and calculates (A + B) / (A−B). The calculated result is output to the CPU 6 as a β value. The CPU 6 obtains the optimum laser power from the input from the jitter detection circuit 8 and the β value and outputs it to the recording control circuit 4. FIG. 4 shows an example of the physical format of the recordable optical disk. In the information recording area of the optical disc, an XAA (eXtended ATIP Area), a PCA (Power Calibration Area), a PMA (Program Memory Area), a lead-in area, a program area, and a lead-out area are formed in order from the inner circumference side. Yes.

In the XAA, for example, additional information such as dye information of the recording layer, a disc manufacturer ID that manufactured the optical disc, and an initial value of the recording power is recorded.
PCA is a test writing area for adjusting recording power, and is an area in which test data is test-written to adjust the recording power of laser light. Details of the PCA are shown in FIG. The PCA is composed of a test area and a count area. The test area is an area where test writing data is written. The count area is an area for identifying a partition (area) used for test writing in the test area. is there. In the figure, 100 partitions are set in the PCA.

The PMA is an area in which address information necessary for adding data is temporarily recorded. The lead-in area and the lead-out area are areas where TOC (Table Of Contents) is recorded, and the program area is an area where actual data is recorded. As described above, the recordable optical disc is provided with the PCA on the inner peripheral side of the disc, but there is also an optical disc provided with the PCA on the outer peripheral side of the disc.

The OPC is performed before actual data is recorded or when a predetermined time has elapsed since the recording was started. When OPC is started, the CPU 6 of the optical disc recording / reproducing apparatus sets the initial value of the laser power to P1. The optical pickup is moved to the test area of the PCA, one unused area is selected from the test area shown in FIG. 5A, and this area is determined as the test writing area. For example, as shown in FIG. 5B, the selected region is divided into three frames, and writing is performed on the first frame with the first laser power P1. Thereafter, writing is performed by sequentially changing the laser power from the second frame to the third frame. In the example shown in FIG. 5B, the first frame is set to the minimum laser power P1, the laser power is sequentially increased from the second frame to the third frame, and the third frame is set to the maximum laser power P3. It is.

When the writing of the test data to all the frames is completed, the written test data is reproduced, the maximum value A and the minimum value B of the reproduced RF signal are obtained, and the calculation formula of (A + B) / (A−B) Then, the β value for each frame is calculated. Each disk is previously written with a β value (β ₀ ) optimum for the disk. This optimum value is read from the disk, and based on the measured three β values, a laser power is obtained so that the written β value becomes β ₀ and applied to the laser diode to output the laser power. Determine the voltage to be used.

For example, data is recorded on and read from the optical disk by a CLV (Constant Linear velocity constant) control method, a zone CLV control method, or the like. The CLV control method is a method of recording data so that the linear velocity is constant over the entire surface of the disk, and the rotational speed of recording and reproduction is gradually decreased toward the outer peripheral side of the radius. In the zone CLV control method, the recording area of the disc is divided into a plurality of zones in the radial direction, and data is recorded / reproduced at a constant linear velocity within each zone. This is a method in which the linear velocity is varied so as to be faster than the inside.

If the recording characteristics are constant over the entire disk surface, the optimum value of the recording power with respect to the linear velocity is constant regardless of the disk radial position. Therefore, when data is recorded on the optical disk with the recording characteristics constant over the entire surface of the disk by the CLV control method, OPC is performed using the PCA provided on the inner circumference side, and the highest recording power is obtained from the innermost circumference by the required recording power. Data can be recorded up to the outer periphery. When data is recorded by the zone CLV control method, the innermost zone is recorded with the recording power determined by the OPC using the PCA provided on the inner circumference side, and other zones are recorded. A method of recording data with a recording power obtained by correcting the recording power determined by the above OPC, or each time a zone is changed, OPC is performed at the linear velocity of the zone to determine the optimum recording power for each zone. Etc. are possible.

However, due to the mechanical characteristics of the disk device, the difference in thermal expansion of the optical disk, uneven coating of the organic dye for recording on the optical disk, etc., the recording characteristics of the optical disk are not constant over the entire disk surface. Often fluctuate. As a countermeasure, ROPC is used in which data is recorded in the user data area of the optical disc, and the recording laser power is controlled based on this information while detecting the amount of reflected light (return light) from the recorded optical disc. . However, with this method, it is difficult to correct the deviation of the optimum recording power with respect to the fluctuation of the laser wavelength.

As a modification of OPC, there is a technique in which PCAs are provided on the inner and outer circumferences of a disk as shown in FIG. In this technology, when data is recorded, it is determined whether the data recording position is closer to the inner PCA or the outer PCA, and OPC is performed using the PCA closer to the data recording position. It is. Compared to the case where OPC is performed using only the inner PCA, the use of the inner PCA and the outer PCA makes it possible to obtain a recording power that is more suitable for the characteristics of the recording position.
The technical literature on OPC includes the following.

Japanese Patent No. 26739779 JP 2003-168216 A JP-A-6-5010 JP 2001-344794 A

Japanese Patent No. 2673979 describes a technique in which, in a rewritable optical disk, a data recording area is grasped in advance and OPC is performed in the middle of the area.
Japanese Patent Laid-Open No. 2003-168216 describes a technique for setting an inner peripheral OPC region and an outer peripheral OPC region.
Japanese Patent Application Laid-Open No. 6-5010 describes a technique for interrupting recording during a recording operation, monitoring the quality of the recording, and correcting the writing parameters.
Japanese Laid-Open Patent Publication No. 2001-344794 describes a technique for adjusting a laser power by interrupting a recording operation and moving to a preset OPC area.

However, even in the conventional technique, the difference between the optimum recording power obtained by using the inner PCA and the actual optimum recording power in the data recording area increases as the data recording area goes to the outer periphery of the disk. Further, the optical disc has a larger surface deviation as it goes to the outer periphery. Therefore, in the OPC using the outer PCA provided on the outermost periphery of the optical disc, there is a large error in the recording and reading of the test data itself, and the error tends to be large in the obtained recording power value. Further, when a difference occurs in the absorption sensitivity with respect to the laser power due to the difference in the composition, thickness, etc. of the photoreactive dye on the optical disk surface, the difference becomes larger as the place is separated. For this reason, the difference between the optimum recording power value obtained by the PCA provided on the innermost circumference or the outermost circumference of the disc and the optimum recording power value in the actual data recording area in the central portion of the disc increases, and the actual data recording is performed. Therefore, the laser power used for the recording becomes inconsistent with the power of the proper quality, and the recording quality is deteriorated.

The present invention does not change the format of a conventional optical disc and does not affect the recording of actual data, and the PCA area is within the actual data recording area and close to the actual data recording location to be actually written. Thus, the OPC is executed in a situation close to the actual data recording area, and the laser power used for recording the actual data is set to a power that provides an appropriate quality for recording. In addition, the present invention is suitable for following the above fluctuation even when the optimum recording power value fluctuates due to a change in the disk environment or the like during the recording of the disk-at-once method. The present invention provides a recording method capable of writing with a large power value.

As a format for recording data on a disc, there is a format called single session or disc at once. Disk at Once (DAO) is a method of recording one session on a single disk with one write. “Write-in recording → data recording → reading with one write”. This is a writing method in which a series of session creation operations called “recording out” is performed only once from the inside to the outside of the disc. Therefore, even if the total amount of data recorded by one writing is less than the amount of data that can be recorded on the disc, and there is space on the disc after recording is completed, data cannot be added later. The address area is left unused without being used.

When requesting recording by disk-at-once, the requesting side determines all data to be recorded, and after making preparations, issues a recording request to the disk device. Therefore, when a disk-at-once request is issued, the amount of data to be recorded including the lead-in and lead-out portions is determined, and the position at which recording ends on the disk can also be determined. In the present invention, in a disc recorded with disc-at-once, an unrecorded portion that is not used at all after recording is used as the PCA area of OPC.

Recording with disc-at-once records a large amount of data continuously at a time, so the temperature of the device rises during recording and the characteristics of the writing laser diode change greatly, or the disc itself deforms and picks up And the distance between the disk surfaces changes. For this reason, it is difficult to obtain sufficient reproduction quality if recording is continued with the laser power value determined by OPC performed at the start of writing. The present invention provides a means for measuring the elapsed time since the start of recording by disk-at-once, a means for measuring the total amount of data recorded on the disk after the start of recording, or a recording operation One of the means for detecting the change of the recording zone of the zone CLV or a plurality of means for monitoring the change in the temperature of the inside apparatus is provided in the apparatus, and the recording data amount is constant for a certain period of time. When a certain amount has been reached, or when a situation such as the temperature change from the start of recording has exceeded a certain amount, OPC is executed and a means for discriminating the power value suitable for the new environment is provided. .

FIG. 1 shows each area of the disc using the unrecorded portion after the user data is recorded by the disc at once as the PCA area. As shown in FIG. 1, since the user data is recorded from the inner circumference side, the free area is generated on the outer circumference side after the area where the user data is recorded. In the present invention, this free area is used as PCA for OPC. In order to know the optimum laser power value for actual data recording, it is necessary to perform trial writing near the actual data writing location. For this reason, the PCA is preferably set continuously in an area where actual data in a free area is recorded. FIG. 2 shows a processing flow of the present invention.

Step 200: It is determined whether or not the data write request is a disk-at-once write. If it is not a disk-at-once, the process proceeds to a normal write process (not shown).
Step 201: Calculate the maximum capacity that can be recorded on the disc. Since disks with different recordable capacities are mixed, the maximum capacity that can be recorded on the disc inserted into the apparatus from XAA or ATIP is identified.
Step 202: Calculate the total amount of data written to the disk from the amount of user data requested to be written and additional information such as lead-in and lead-out.
Step 203: From the amounts calculated in Step 200 and Step 201, the capacity of the unrecorded portion of the program area in which user data generated after user data writing is not recorded and the start address of the unrecorded portion are determined. To do. Since this area is used as a new PCA, the head address of the unrecorded part is stored in the storage unit of the disk device, and information indicating the test area and count area is set. The number of hearts to be set in the new PCA can be set according to the size of the empty area, but is set to 100, for example, as in the conventional OPC.
Step 204: Determine the optimum power when starting to write actual data by OPC. The PCA of OPC can use the conventional inner PCA or the outer PCA, or can use the new PCA set in step 203. Since user data is recorded from the inside of the user area, it is desirable to perform OPC using the inner PCA.
Step 205: A predetermined amount of data is recorded with the determined optimum laser power, and the recorded data is integrated and the elapsed time is integrated.
Step 206: Collect information for determining whether or not it is necessary to re-execute OPC, such as measurement of accumulated data amount, accumulated time, and temperature in the apparatus. The amount of data recorded since the previous OPC was executed has reached a predetermined amount, a predetermined time has elapsed since the previous OPC was executed, the zone where the data is to be recorded has changed, and the temperature in the device has been changed to the previous OPC. It is inspected whether or not an event that affects the recording laser power has occurred, for example, a predetermined amount has changed. If it is detected that an event has occurred, the process proceeds to step 207 to execute a new OPC. If no event has occurred, the process proceeds to step 209.
Step 207: The start address of the new PCA area stored in step 203 is read, and the pickup is moved to the new PCA area based on this address. An unused test partition is selected from the new PCA area as the partition to be used this time.
Step 208: Set the rotation speed of the test writing to the rotation speed at which actual data is recorded, and execute OPC. By making the rotation speed when writing test data the rotation speed used when recording actual data, OPC is possible in an environment close to the actual data writing environment. The laser power value obtained by this OPC is set to the leather power value of actual data writing.
Step 209: discriminates whether or not recording of data to be recorded has been completed by disc-at-once. If data to be recorded still remains, return to step 205, and the laser determined by OPC in step 208 Record using power values. When all the data has been recorded, the process proceeds to step 210 to execute the final process.

The present invention has the following effects because an unrecorded area that is not required for recording by disk-at-once is used as the PCA area of OPC.
1. The outermost area of the area where data is recorded is the part where the linear velocity during recording is the fastest and it is most difficult to ensure proper reproduction quality after recording. In the present invention, OPC is performed on the disk surface adjacent to the most severe part. Therefore, it is possible to determine a laser power value that ensures good reproduction quality even in a data area where it is difficult to determine an optimum power value in the PCA area on the inner circumference side.
2. The present invention is not an outermost circumference with a large disc warp or shakiness, but is an area where user data is originally recorded, but an area that is wasted as a non-use area due to the characteristics of recording by disk-at-once. This is a configuration used as an area. For this reason, warpage which becomes a problem when the PCA area set on the outermost periphery of the disk is used, the influence of surface blurring is reduced, and good OPC is possible.
3. Unlike ROPC, which detects the amount of reflected light (returned light) from the recorded optical disk and controls the recording laser power based on this information, the recording laser power is determined by actually recording the data in the actual data recording area. The optimum laser power can be obtained every time regardless of the influence of fluctuations in the laser wavelength.

The figure which shows the data area of the optical disk to which this invention was applied Flow chart of recording laser power optimization according to the present invention Optical disc recording / reproducing device Diagram of data area of prior art optical disc Diagram of test writing area for recording laser power optimization Diagram showing data area of optical disc

Claims (2)

An optimum power recording method in an optical disk storage device,
Determining a start address of an unrecorded portion of a program area in which user data generated when recording is completed is recorded from the amount of data recordable on the optical disc and the amount of user data recorded on the optical disc;
Performing test writing on the unrecorded portion before starting recording data to obtain optimum recording power;
Recording data with the obtained optimum recording power;
A method characterized by comprising: The method of claim 1, comprising:
The method further comprises the step of performing the trial writing before the end of data recording and obtaining the optimum recording power in the unrecorded portion.

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