JP2008140523A - Device and method for optical information recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device and a method for optical information recording, capable of easily setting proper recording power. <P>SOLUTION: This method includes the step S106 of executing, in a drive 100 for recording information in a disk 10 by emitting a blue laser of predetermined recording power, test recording where recording power is changed, and setting recording power based on an asymmetry value contained in the reproduced signal of the test recording, the step S110 of executing test recording where recording power is changed, and setting recording power based on the modulation degree (m) of a longest recording mark 8T contained in the reproduced signal of the test recording, and the step S104 of selecting either one of the steps S106 and S110 based on an OPC method recorded in the disk 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical information recording apparatus and an optical information recording method for recording information on an optical information recording medium writable by a blue laser such as BD-R and HD DVD-R.

Conventionally, as an optical information recording apparatus using a red laser, in order to set an optimum recording power that varies depending on the use environment of the optical information recording apparatus, the type of the optical information recording medium, etc. Test recording is performed at a plurality of levels of recording power considering the wavelength variation of the laser diode, and β values at each recording power are obtained from the RF signal of the test recording, and each β value is linearly approximated as shown in FIG. It is known that the recording power when the target β value β0 on the straight line is set as the optimum recording power P0 (see, for example, Patent Document 1).
JP-A-9-134403

  On the other hand, optical information recording devices and optical information recording media are required to have higher speeds and larger capacities. To meet this demand, optical information recording devices using blue lasers (hereinafter simply referred to as drives) and blue lasers are used. There is a corresponding optical information recording medium (hereinafter simply referred to as a disk).

  In the conventional drive, signal processing such as PRML (Partial Response Maximum Likelihood) is performed. Therefore, even if the recording power is controlled based on the β value in the RF signal, an appropriate recording power may not be set. An appropriate recording power was set based on the asymmetry value.

  However, in some discs corresponding to the blue laser, the asymmetry value does not change linearly with respect to the change in the recording power, so that an appropriate recording power can be set based on the asymmetry value in the RF signal. There was a problem that it was not possible.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical information recording apparatus and an optical information recording method capable of easily setting an appropriate recording power.

  In order to achieve the above object, the present invention performs test recording with varying recording power in an optical information recording apparatus that records information on an optical information recording medium by irradiating a blue laser with a predetermined recording power. Asymmetry value recording power setting means for setting the recording power based on the asymmetry value in the recording reproduction signal, and test recording with the recording power changed, and based on the modulation degree of the longest recording mark in the reproduction signal of the test recording Selection that selects either one of an asymmetry value recording power setting unit and a modulation degree recording power setting unit based on predetermined information recorded on the optical information recording medium, and a modulation degree recording power setting unit that sets recording power An optical information recording apparatus comprising means is proposed.

  According to this optical information recording apparatus, one of the asymmetry value recording power setting means and the modulation degree recording power setting means is selected based on the predetermined information recorded on the optical information recording medium. The recording power setting based on the recording length and the recording power setting based on the modulation depth of the longest recording mark are not performed, and the asymmetry value in the test recording playback signal does not change linearly with the change in recording power. Even in an information recording medium, the recording power can be set based on the modulation degree of the longest recording mark in the reproduction signal of the test recording.

  According to another aspect of the present invention, there is provided an optical information recording method for recording information on an optical information recording medium by irradiating a blue laser having a predetermined recording power in order to achieve the above object. To select one of the recording power setting based on the asymmetry value and the recording power setting based on the modulation factor, and change the recording power when the recording power setting based on the asymmetry value is selected. The recording power is set based on the asymmetry value in the reproduction signal of the test recording, and when the recording power setting based on the modulation degree is selected, the test recording is performed by changing the recording power, An optical information recording method is proposed in which the recording power is set based on the modulation degree of the longest recording mark in the reproduction signal of the test recording.

  According to this optical information recording method, one of a recording power setting based on an asymmetry value and a recording power setting based on a modulation degree is selected based on predetermined information recorded on the optical information recording medium. Therefore, the recording power setting based on the asymmetry value and the recording power setting based on the modulation length of the longest recording mark are not performed, and the asymmetry value in the test recording playback signal is linear with respect to the recording power change. Even in an optical information recording medium that does not change rapidly, the recording power can be set based on the modulation degree of the longest recording mark in the reproduction signal of the test recording.

  According to the optical information recording apparatus of the present invention, both the recording power setting based on the asymmetry value and the recording power setting based on the modulation degree of the longest recording mark are not performed, and the asymmetry value in the reproduction signal of the test recording However, even in an optical information recording medium that does not change linearly with respect to the change in recording power, the recording power can be set based on the modulation degree of the longest recording mark in the reproduction signal of the test recording. The recording power can be set with time, and an appropriate recording power according to the optical information recording medium can be easily set.

  Further, according to the optical information recording method of the present invention, both the recording power setting based on the asymmetry value and the recording power setting based on the modulation degree of the longest recording mark are not performed. Even in an optical information recording medium in which the asymmetry value does not change linearly with respect to the change in recording power, the recording power can be set based on the modulation degree of the longest recording mark in the reproduction signal of the test recording. Therefore, the recording power can be set in a short time, and an appropriate recording power corresponding to the optical information recording medium can be easily set.

  1 to 6 show an embodiment of the present invention, FIG. 1 is a schematic block diagram of an optical information recording apparatus, FIG. 2 is a plan view for explaining the disk shown in FIG. 1, and FIG. 4 is a conceptual diagram showing the amplitude of the longest recording mark and the shortest recording mark, FIG. 4 is a flowchart of the recording power setting process, FIG. 5 is a graph showing the relationship between the recording power and the asymmetry value, and FIG. It is a graph which shows the relationship with the change rate of.

  As shown in FIG. 1, an optical information recording apparatus (hereinafter simply referred to as a drive) 100 includes an encoder 101, a strategy circuit 102, a laser oscillator 103, a collimator lens 104, a half mirror 105, an objective lens 106, a condenser lens 107, a light receiving element. Unit 108, signal detection circuit 109, code determination circuit 110, decoder 111, code determination circuit 112, asymmetry value detection circuit 113, modulation degree detection circuit 114, control circuit 115, and storage circuit 116, and recording is possible. Information is recorded or reproduced by irradiating an optical information recording medium (hereinafter simply referred to as a disk) 10 with a blue laser.

  The encoder 101 is for encoding a recording signal corresponding to predetermined recording information, and outputs recording data encoded by a predetermined encoding method, for example, 1-7PP modulation method, to the strategy circuit 102. .

  The strategy circuit 102 is for setting a light strategy, which is an irradiation condition of the blue laser, and various parameters for a predetermined light strategy are set. The strategy circuit 102 corrects various parameters of the strategy based on a control signal input from a control circuit 115 described later, and generates a recording pulse that will obtain a desired recording state on the disk 10. Is output.

  The laser oscillator 103 controls the intensity and pulse width of the blue laser output corresponding to the recording pulse, and the controlled blue laser is supplied at a constant linear velocity or angular velocity via the collimator lens 104, the half mirror 105, and the objective lens 106. The disk 10 rotating at a constant degree is irradiated. As a result, a recording mark string composed of recording marks and spaces (between the recording marks) is formed on the recording layer of the disk 10, and predetermined recording information is recorded.

  On the other hand, when reproducing the information recorded on the recording layer of the disk 10, the laser oscillator 103 uses a uniform reproduction blue laser through the collimator lens 104, the half mirror 105, and the objective lens 106 at a constant linear velocity or The rotating medium 10 is irradiated with a constant angular velocity.

  The reproduction blue laser uses a blue laser whose intensity is lower than that of the blue laser at the time of recording. The light receiving unit 108 reflects the reflected light from the medium 10 by the reproduction blue laser with an objective lens 106, a half mirror 105, and a condenser lens. Light is received via 107, converted into an electrical signal, and output to the signal detection circuit 109.

  As shown in FIG. 2, the electric signal output from the light receiving unit 108 is an OPC (Optical Power Control) method that represents a setting method of a medium ID and recording power recorded in the setting area 11 of the inner periphery of the disk 10. The signal detection circuit 109 detects an RF signal and a wobble signal included in the electric signal, and detects a sign determination circuit 110 and an asymmetry value detection circuit 113 described later. In addition, an RF signal is output to one of the modulation degree detection circuit 114 and a wobble signal is output to a code determination circuit 112 described later.

  The code determination circuit 110 generates a clock signal having a predetermined period T from the encoded RF signal by encoding the RF signal by binarization processing such as the above-described PRML, and sends the encoded RF signal to the decoder 111. Output.

  The decoder 111 further decodes the encoded RF signal and outputs it as a reproduction signal.

  The code determination circuit 112 outputs the media ID and the OPC method included in the wobble signal input from the signal detection circuit 109 to the control circuit 115.

  The asymmetry value detection circuit 113 detects the asymmetry value in the RF signal input from the signal detection circuit 109 and outputs it to the control circuit 115.

  The modulation degree detection circuit 114 detects the modulation degree of the longest recording mark in the RF signal input from the signal detection circuit 109, calculates the change rate of the detected modulation degree with respect to the recording power, and controls the calculated modulation degree change rate. It is output to the circuit 115.

  The control circuit 115 is a well-known microprocessor having a CPU, a memory such as a RAM, a ROM, etc., and operates based on an input signal and a program stored in advance in its own memory to determine a selection unit 115a and a strategy. Part 115b. The selection unit 115a is for selecting a recording power setting method suitable for the disk 10, and based on the OPC method input from the code determination circuit 112, the signal detection circuit 109 and the asymmetry value detection circuit 113 and the modulation degree are selected. A control signal is output to the signal detection circuit 109 so as to output an RF signal to any one of the detection circuits 114, and the medium ID input from the code determination circuit 112 and the information stored in the storage circuit 116 are strategies. The data is output to the determination unit 115b. The strategy determination unit 115b is for determining the write strategy corresponding to the disk 10, and is stored in the storage circuit 116 and the media ID input from the selection unit 115a and the information stored in the storage circuit 116. Based on the standard recording conditions and the asymmetry value input from the asymmetry value detection circuit 113 or the modulation rate change rate input from the modulation level detection circuit 114, the recording power is recorded so that the β value of the reproduction signal becomes the target β value. A control signal is output to the strategy circuit 102 so that the strategy circuit 102 generates a pulse.

  The storage circuit 116 is composed of a rewritable recording element such as an EEPROM and the like. The recording circuit 116 is set for each media ID recorded on the disk 10 and has a recording condition for obtaining an appropriate reproduction signal with a standard drive and a standard disk. A standard recording condition to be expressed, a target asymmetry value A0 representing an asymmetry value at an optimum recording power, a target modulation degree change rate dm0 / dP representing a modulation degree change rate at a predetermined recording power, and constants for obtaining an optimum recording power. A recording power coefficient ρ is stored.

  The record mark string formed on the disk 10 theoretically has a length of nT (n is a positive integer) with respect to the period T of the clock signal generated by the sign determination circuit 110 of the drive 100. For example, a plurality of recording marks having different lengths such as n = 2 to 8 may be formed for each medium ID recorded in 10. A recording pulse corresponding to each recording mark is set by the strategy circuit 102. In the following description, unless otherwise specified, a recording mark having a length nT (n = 2 to an integer of 2 to 8) corresponds to a media ID.

  Here, as shown in FIG. 3, the asymmetry value A detected by the asymmetry value detection circuit 113 includes the high level amplitude I2H and the low level amplitude I2L in the shortest recording mark 2T of the RF signal, and the longest recording of the RF signal. The high level amplitude I8H and the low level amplitude I8L in the mark 8T are expressed by the following equation (1).

A = {(I8H + I8L) − (I2H + I2L)} / {2 × (I8H−I8L)} (1)
The modulation degree m detected by the modulation degree detection circuit 114 is expressed by the following equation (2) from the high level amplitude I8H and the low level amplitude I8L in the longest recording mark 8T of the RF signal.

m = (I8H-I8L) / I8H (2)
In such a recording system composed of the drive 100 and the disk 10, the target recording power setting process S100 is executed before recording predetermined recording information in the recording area 12 of the disk 10.

  That is, as shown in FIG. 4, when the disk 10 is loaded in the drive 100, the laser oscillator 103 irradiates the setting area 11 of the disk 10 with the reproduction blue laser to reproduce the information in the setting area 11, and the selection unit 115a. Acquires the media ID input from the code determination circuit 112, and the strategy determination unit 115b acquires the media ID from the selection unit 115a (step S101).

  Next, the strategy determination unit 115b reads and sets the standard recording condition corresponding to the acquired media ID from the storage circuit 116 (step S102), and the selection unit 116a acquires the OPC method input from the code determination circuit 112 ( Step S103).

  Next, the selection unit 115a determines whether or not the acquired OPC method is a recording power setting based on an asymmetry value of the RF signal (step S104).

  As a result of the determination in step S104, when the OPC system sets the recording power based on the asymmetry value of the RF signal, the recording power is changed from the standard recording condition, and the recording condition includes the recording pulses of the shortest recording mark 2T and the longest recording mark 8T. Then, the laser oscillator 103 irradiates the setting area 11 of the disk 10 with a blue laser to perform test recording (step S105).

  Next, the laser oscillator 103 irradiates the reproduction blue laser to the setting area 11 of the disk 10 to reproduce the test recording, and the selection unit 115a signals that the signal detection circuit 109 outputs the RF signal to the asymmetry value detection circuit 113. In addition to outputting a control signal to the detection circuit 109, the target asymmetry value A0 corresponding to the media ID is read from the storage circuit 116 and output to the strategy determination unit 115b. The asymmetry value detection circuit 113 is an RF input from the signal detection circuit 109. The asymmetry value A represented by the above-described equation (1) is detected from the signal and output to the strategy determining unit 115b (step S106).

  The strategy determination unit 115b uses the recording power P0 when the asymmetry value A input from the asymmetry value detection circuit 113 becomes the target asymmetry value A0 input from the selection unit 115a to the recording area 12 of the disc 10 as predetermined recording information. Is set as the recording power for recording (step S107).

  Here, in the case of the disc 10 in which the OPC method is set to the asymmetry value of the RF signal, the asymmetry value A of the RF signal detected by the asymmetry value detection circuit 113 is a change in the recording power P as shown in FIG. On the other hand, it changes linearly. Thereby, the optimum recording power can be set.

  As a result of the determination in step S104, when the OPC method is to set the recording power based on the modulation degree of the longest recording mark of the RF signal, the recording power is changed from the standard recording condition, and the recording including the recording pulse of the longest recording mark 8T is performed. Under the condition, the laser oscillator 103 irradiates the setting area 11 of the disk 10 with a blue laser to perform test recording (step S108).

  Next, the laser oscillator 103 irradiates the reproduction blue laser to the setting area 11 of the disk 10 to reproduce the test recording, and the selection unit 115a signals that the signal detection circuit 109 outputs the RF signal to the modulation degree detection circuit 114. In addition to outputting a control signal to the detection circuit 109, the target modulation degree change rate dm0 / dP and the power recording coefficient ρ corresponding to the media ID are read from the storage circuit 116 and output to the strategy determination unit 115b. Detects the modulation degree m of the longest recording mark 8T represented by the above-described equation (2) from the RF signal input from the signal detection circuit 109 (step S109), and records the detected modulation degree m of the longest recording mark 8T. The modulation factor change rate dm / dP with respect to power is calculated and output to the strategy determining unit 115b (step S110).

  The strategy determining unit 115b obtains the recording power Pt when the modulation degree change rate dm / dP input from the modulation degree detection circuit 114 becomes the target modulation degree change rate dm0 / dP input from the selection unit 115a. The recording power P0 represented by the following equation (3) is set as the recording power for recording predetermined recording information in the recording area 12 of the disk 10 (step S111).

P0 = ρ × Pt (3)
Here, in the case of the disk 10 in which the OPC method is set to the modulation degree of the longest recording mark of the RF signal, the modulation degree calculated as the modulation degree m of the longest recording mark 8T of the RF signal detected by the modulation degree detection circuit 114. The degree change rate dm / dP changes as shown in FIG. Thus, both the setting of the recording power based on the asymmetry value and the setting of the recording power based on the modulation degree of the longest recording mark are not performed, and the asymmetry value A in the test recording reproduction signal corresponds to the change in the recording power. Even with the disk 10 that does not change linearly, the recording power P0 can be set based on the modulation degree m of the longest recording mark 8T in the RF signal of the test recording.

  As described above, according to the present invention, based on the OPC method recorded in the setting area 11 of the disc 10, any one of the setting of the recording power based on the asymmetry value and the setting of the recording power based on the modulation degree of the longest recording mark is performed. Therefore, the recording power setting based on the asymmetry value and the recording power setting based on the modulation degree of the longest recording mark are not performed, and the asymmetry value A in the reproduction signal of the test recording is the recording power. Even in the case of the disk 10 that does not change linearly with respect to the change in the recording power, the recording power P0 can be set based on the modulation degree m of the longest recording mark 8T in the RF signal of the test recording. The recording power P0 can be set, and an appropriate recording power corresponding to the disk 10 can be easily set.

  The configuration and operation of the present invention are not limited to the above-described embodiments, and various modifications may be made without departing from the scope of the present invention.

Schematic block diagram of optical information recording device FIG. 2 is a plan view illustrating the disk shown in FIG. Conceptual diagram showing the amplitude of the longest record mark and the shortest record mark in the playback signal Flow chart of recording power setting process Graph showing the relationship between recording power and asymmetry value Graph showing the relationship between recording power, modulation factor, and modulation rate change rate Graph showing the relationship between recording power and β value in the conventional recording power setting

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Disk, 100 ... Drive, 113 ... Asymmetry value detection circuit, 114 ... Modulation degree detection circuit, 115a ... Selection part, 115b ... Strategy determination part.

Claims (6)

In an optical information recording apparatus for recording information on an optical information recording medium by irradiating a blue laser with a predetermined recording power,
Asymmetry value recording power setting means for performing test recording with varying recording power and setting recording power based on an asymmetry value in a reproduction signal of the test recording;
Modulation degree recording power setting means for performing test recording with varying recording power and setting the recording power based on the modulation degree of the longest recording mark in the reproduction signal of the test recording;
An optical information recording comprising: selection means for selecting one of an asymmetry value recording power setting means and a modulation degree recording power setting means based on predetermined information recorded on an optical information recording medium apparatus. The asymmetry value recording power setting means includes means for setting a recording power when an asymmetry value in a reproduction signal of a test recording becomes a target asymmetry value set for an optical information recording medium. 2. The optical information recording apparatus according to 1. The modulation degree recording power setting means calculates a change rate with respect to the recording power of the modulation degree of the longest recording mark in the reproduction signal of the test recording, and the calculated modulation degree change rate is set for the optical information recording medium. The optical information recording apparatus according to claim 1, further comprising means for setting a recording power based on a recording power at which the modulation factor change rate is reached. In an optical information recording method for recording information on an optical information recording medium by irradiating a blue laser with a predetermined recording power,
Based on the predetermined information recorded on the optical information recording medium, select either one of the setting of the recording power based on the asymmetry value and the setting of the recording power based on the modulation degree,
When the recording power setting based on the asymmetry value is selected, the test recording is performed by changing the recording power, and the recording power is set based on the asymmetry value in the reproduction signal of the test recording,
When recording power setting based on the modulation degree is selected, test recording is performed by changing the recording power, and the recording power is set based on the modulation degree of the longest recording mark in the reproduction signal of the test recording. An optical information recording method. 5. The recording power at which the asymmetry value in the reproduction signal of the test recording becomes a target asymmetry value set for the optical information recording medium when the recording power is set based on the asymmetry value is set. The optical information recording method according to 1. When setting the recording power based on the modulation factor, the rate of change of the modulation factor of the longest recording mark in the reproduction signal of the test recording with respect to the recording power is calculated, and the calculated modulation factor change rate is set for the optical information recording medium. The optical information recording method according to claim 4, further comprising: setting a recording power based on a recording power at which the target modulation degree change rate is reached.

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