JP2008140451A - Optical disc apparatus and recording power value determination method - Google Patents

Abstract

An optimum recording power value is obtained for both an inner circumference OPC of a first recording layer and an inner circumference OPC of a second recording layer.
An asymmetry value for each test recording power value obtained by recording test data with a plurality of test recording power values from an optical pickup side to an inner test writing area of a first recording layer of an optical disc. The recording power value at the inner circumference OPC is determined according to the recording power value characteristic obtained from the above. Then, test data is recorded in the outer peripheral test writing area of the second recording layer based on the recording power value of the inner peripheral OPC, an asymmetry value is obtained from the reproduction signal, and the asymmetry value and the optical disc coefficient are obtained based on the obtained asymmetry value. The outer peripheral recording power value of the two recording layers is obtained.
[Selection] Figure 2

Description

  The present invention relates to an optical disc apparatus and a recording power value determination method for obtaining an optimum recording power value when data is recorded on an optical disc.

  When writing data on an optical disc, the irradiation intensity of the laser beam greatly affects the reliability of the written data. Therefore, it is necessary to control the irradiation intensity (recording power value) of the laser beam in order to improve the reliability of the written data.

  In order to control the recording power value, OPC (Optimum Power Calibration) is performed before writing data on the optical disc. This OPC is control for setting an optimum recording power value.

  In OPC, test data is written with a plurality of recording power values in a PCA (Power Calibration Area) provided on the optical disk. The β value is obtained for each recording power value from the reproduction signal of the written test data. Then, the recording power value that is the target β value is obtained from the recording power value characteristic of the β value.

By the way, in the case of writing data to a two-layer (DL) optical disc apparatus as a conventional method for obtaining the optimum recording power, the optimum recording power value is different between the first layer and the second layer. (For example, refer to Patent Document 1).
JP 2006-127593 A

  However, in the invention described in Patent Document 1, since the test data is recorded on each of the two recording layers with a plurality of recording power values to obtain the optimum value, the correct optimum value is obtained particularly in the second layer. There may not be.

  An object of the present invention is to provide an optical disc apparatus and a recording power value determination method capable of obtaining an optimum recording power value for writing data to an optical disc having two or more recording layers.

  In order to achieve the above object, an optical disc apparatus of the present invention includes an optical pickup device that moves an optical pickup head to an optical disc to record or reproduce data, a spindle motor that rotationally drives the optical disc, the optical pickup device, and A controller that controls the spindle motor to execute recording / reproduction of the optical disc, and the controller records test data with a plurality of test recording power values in the inner test writing area of the optical disc. An inner circumference recording power value is determined based on the reproduction signal, test data is recorded in the outer peripheral test writing area based on the inner circumference recording power value, an outer circumference recording power value is obtained based on the reproduction signal, and the outer circumference recording power is calculated. The optimum outer peripheral recording power value is obtained by correction.

  The recording power value determination method for the optical disc apparatus according to the present invention records test data with a plurality of test recording power values in the inner test writing area of the optical disc, and determines the inner recording power value based on the reproduction signal. Determine and record test data in the outer peripheral test writing area based on the inner recording power value, obtain the outer recording power value based on the reproduction signal, and correct the outer recording power to obtain the optimum outer recording power value. It is characterized by that.

  According to the present invention, it is possible to obtain an optimum recording power value for writing data on an optical disc having two or more recording layers.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a block diagram showing an optical disc apparatus according to an embodiment of the present invention.

  The optical disc apparatus ODD includes a spindle motor (SPM) 101 that rotates the optical disc 100, a pickup head 102, an RF amplifier 103, a signal detection circuit 111, a CPU 112, a recording control circuit 113, an encoder 114, a laser diode (LD) drive circuit 115, and a servo. A circuit 116, an interface (I / F) unit 117, a buffer memory 118, a β value calculation unit 119, a characteristic calculation unit 120, a memory 121, a peak detection unit 131, a bottom detection unit 132, and AD converters 141 to 143 are provided. To do. The pickup head 102 includes a laser diode, an optical system such as an objective lens, a focusing actuator, a tracking actuator, a photo detector, and a lens position sensor.

  The memory 121 stores various programs and various data.

  The recording surface of the optical disk 100 rotated by the spindle motor 101 is irradiated with a laser beam emitted from the laser diode of the pickup head (PUH) 101, and data recording / reproduction is performed. The reflected light reflected from the optical disc 100 is detected by the photodetector of the pickup head 102 and converted into an electric signal.

  The output signal of the pickup head 102 is amplified by the RF amplifier 103. The signal amplified by the RF amplifier 103 is input to the signal detection circuit 111 via the AD converter 143, and is input to the peak detection unit 131 and the bottom detection unit 132.

  The signal detection circuit 111 extracts a wobble component from the input signal. The signal detection circuit 111 detects the track address of the optical disc 100 irradiated with the laser beam based on the extracted wobble component, and outputs the detected address to the CPU 112. The CPU 112 recognizes the radial recording position of the optical disc 100 from the input address, and outputs a control signal corresponding to the recording position to the recording control circuit 113.

  Further, data D1 sequentially given from the host computer PC is taken in via the interface unit 117 and is sequentially stored in the buffer memory 118. The encoder 114 modulates the data stored in the buffer memory 118 in accordance with the format of the optical disc, for example, if it is a CD, based on the EFM modulation (Eight Fourteen Modulation) method, and outputs the modulated signal to the recording control circuit 113.

  The recording control circuit 113 outputs a drive control signal to the laser diode drive circuit 115 and the servo circuit 116 based on the modulation signal from the encoder 114 and the control signal from the CPU 112. The servo circuit 116 controls the rotation of the spindle motor 101 and sets the position of the pickup head 102 to an appropriate position. The laser diode drive circuit 115 energizes the laser diode of the pickup head 102 based on the drive control signal, and irradiates the optical disc 100 with a laser beam from the laser diode.

  A procedure of OPC (Optimum Power Calibration) when data is recorded on the optical disc 100 by the optical disc apparatus ODD shown in FIG. 1 will be described with reference to the flowchart of FIG.

  First, the CPU 112 notifies the recording control circuit 113 of the recording speed in accordance with the value designated by the recording command sent from the host computer PC. Next, the CPU 112 acquires the ID number and the total number information recorded in the lead-in area of the optical disc 100 that records data, and determines the type of the optical disc 100 from the ID number (step S11).

  Next, the CPU 112 acquires a start recording power value and a step value corresponding to the recording speed from a table stored in the memory 121, and an inner circumference PCA (Power Calibration Area: trial writing area) of the first recording layer (L0). ) Is determined (step S12).

  The CPU 112 changes the recording power value by 15 steps from the selected start recording power value in units of step values, and records test data on the inner circumference PCA (trial writing area) of the first recording layer of the optical disc 100 (step S13). ).

  Next, the test data recorded on the inner circumference PCA of the first recording layer of the optical disc 100 is reproduced (step S14). During reproduction, an RF signal corresponding to the reflected light from the optical disc 100 received by the pickup head 102 is input to the RF amplifier 103. The RF amplifier 103 amplifies the input RF signal, and the amplified RF signal is input to the peak detection unit 131 and the bottom detection unit 132.

  The peak detector 131 detects the peak value of the RF signal and supplies it to the AD converter 141. The AD converter 141 converts the supplied peak value (A) into a digital signal and supplies it to the β value calculation unit 119. Similarly, the bottom detector 132 detects the bottom value (B) of the RF signal and supplies it to the AD converter 142. The AD converter 142 converts the supplied bottom value (B) into a digital signal, and supplies the digital signal to the β value calculation unit 119. The β value calculator 119 calculates a β value (asymmetry value) for each of the 15 recording power values (step S15).

  That is, the β value calculation unit 119 calculates a β value for each recording power value according to the input peak value (A) and bottom value (B), and supplies the result to the characteristic calculation unit 120. The β value is calculated using the following formula:

β = (A + B) / (A−B)
Next, the characteristic calculator 120 calculates the recording power value characteristic of the β value from the β value obtained for each recording power value (step S16). The characteristic calculation unit 120 calculates an approximate expression indicating the relationship between the recording power value and the β value as the characteristic, and supplies the approximate expression to the CPU 112.

  The CPU 112 reads the target β value corresponding to the recording speed recorded in the memory 121, and determines the optimum inner circumference recording power value in the inner circumference OPC using the supplied approximate expression (step S17). The determined inner recording power value is stored in the memory 121 and supplied to the recording control circuit 113.

  Next, the CPU 112 determines whether or not the optical disc 100 has two recording layers (DL) from the type of the optical disc 100 acquired in step S11 (step S18).

  When it is determined that there are two recording layers (Yes in step S18), the CPU 112 executes the outer periphery OPC in the second recording layer. Hereinafter, the processing of the outer periphery OPC in the second recording layer will be described.

  First, the CPU 112 reads a coefficient corresponding to a predetermined disk type from the memory 121. The read coefficient and the inner recording power value of the first recording layer determined in step S105 are calculated (multiplied), and the calculation result is used as the test recording power value for the second recording layer.

  The CPU 112 records test data on the outer peripheral PCA (Power Calibration Area) of the second recording layer of the optical disc 100 using the test recording power value determined in Step S19 (Step S20). Next, the CPU 112 reproduces the test data recorded on the outer peripheral PCA of the second recording layer (step S21). Then, the β value is calculated in the same manner as the inner circumference OPC of the first recording layer (step S22).

  The CPU 112 determines a correction amount for correcting the deviation of the recording state from the test recording power value and β value at the outer periphery OPC of the second recording layer and the approximate expression of the inner periphery OPC obtained at step S16 (step S23).

  That is, the CPU 112 obtains the slope at the target β value from the above-described approximate expression of the inner circumference OPC. Then, a linear expression of the obtained inclination is obtained through the intersection of the test recording power value at the outer periphery OPC determined in step S19 and the β value calculated in step S22.

  Then, the optimum outer peripheral recording power value is determined from the obtained linear expression and the target β value (step S24). The determined optimum outer peripheral recording power value is stored in the memory 121 and supplied to the recording control circuit 113.

  FIG. 3 shows a recording power curve of the second recording layer obtained by the outer periphery OPC. The curve shown by the solid line in FIG. 3 is the recording power at each position of the disk according to the result of the inner circumference OPC and the power curve determined for each disk in advance. Recording can be performed with high recording quality on the second recording layer by adding correction by the outer periphery OPC to the recording power of the solid line and changing the recording power as shown by the dotted line.

  Although the slope of the power value β varies depending on the power level, in the embodiment, the outer peripheral OPC is performed on the second recording layer using a coefficient and a test recording power value determined in advance for each disk. The power is near the β value.

  After step S24 or when it is determined in step S18 that the recording layer is not two layers (No in step S18), data recording is started (step S25).

With the above processing, the optimum recording power value can be obtained for both the inner circumference OPC of the first recording layer and the outer circumference OPC of the second recording layer. The test data is recorded by the outer periphery OPC of the second recording layer only once using the recording power value determined in step S19, and the temperature increase of the optical disk can be suppressed. As a result, it is possible to obtain the optimum recording power value for both the first recording layer and the second recording layer. The present invention is not limited to the above-described embodiment as it is, and does not depart from the spirit of the invention in the implementation stage. The component can be modified and embodied. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

1 is a block diagram showing an outline of an optical disc apparatus according to an embodiment of the invention. 6 is a flowchart showing an OPC processing procedure of the optical disc apparatus of the embodiment. The figure which shows the recording power curve of the 2nd recording layer obtained by outer periphery OPC of embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Optical disk, 101 ... Spindle motor, 102 ... Pickup head, 103 ... RF amplifier, 111 ... Signal detection circuit, 112 ... CPU, 113 ... Recording control circuit, 114 ... Encoder, 115 ... Laser drive circuit, 116 ... Servo circuit, DESCRIPTION OF SYMBOLS 117 ... Interface part, 118 ... Buffer memory, 119 ... (beta) value calculating part, 120 ... Characteristic calculating part, 121 ... Memory, 131 ... Peak detecting part, 132 ... Bottom detecting part, 141 ... AD converter

Claims (3)

An optical pickup device for recording or reproducing data by moving an optical pickup head to an optical disc;
A spindle motor that rotationally drives the optical disc;
A controller for controlling the optical pickup device and the spindle motor to execute recording / reproduction of the optical disc,
The controller records test data with a plurality of test recording power values in the inner circumference test writing area of the optical disc, determines an inner circumference recording power value based on the reproduction signal, and determines an outer circumference according to the inner circumference recording power value. An optical disc apparatus characterized in that test data is recorded in a test writing area, an outer peripheral recording power value is obtained based on a reproduction signal, and the outer peripheral recording power is corrected to obtain an optimum outer peripheral recording power value. A storage device for storing a coefficient corresponding to the type of the optical disc;
2. The optical disc apparatus according to claim 1, wherein the controller calculates the outer peripheral recording power by calculating a coefficient corresponding to the type of the optical disc read from the storage device and the inner recording power value. Recording test data with a plurality of test recording power values for the inner test writing area of the optical disc,
The inner recording power value is determined based on the reproduction signal,
Record test data in the outer periphery test writing area by the inner periphery recording power value,
Obtain the outer peripheral recording power value based on the reproduction signal,
A method for determining a recording power value of an optical disc apparatus, wherein the outer peripheral recording power is corrected to obtain an optimum outer peripheral recording power value.

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