JP2002358643A - Information recorder and information recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a laser beam of a desired light quantity to always be outputted from a laser beam source, even in the case where the laser beam emitted from the laser beam source is deteriorated with the lapse of time, or the media performance of an optical disk and the performance of the laser beam source are changed by high temperature of laser beam at the time of recording information. SOLUTION: A system controller 15 figures out a relational expression between a laser emission driving current supplied by a laser control part 6 and a light quantity measured by a front PD 4 and a light quantity acquisition part 8 before data recording to an optical disk medium 20 and stores it in a RAM 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optimum laser power calibration (abbreviated as "OPC") for measuring a recording condition by setting a multi-step recording power on a recording medium such as an optical disk which is recordable or rewritable. The present invention relates to an information recording apparatus and an information recording method for realizing an accurate recording power output when performing recording and setting a recording power suitable for a recording medium.

[0002]

2. Description of the Related Art In recording information on a recordable or rewritable optical disk, the information must be applied to a laser light source according to conditions such as media characteristics of the optical disk and characteristics of a laser light source (LD) of an information recording apparatus (recording drive). The laser emission drive current is floating. In general, before performing recording in an actual data area, a recording power (that is, a “laser emission drive current”) is applied to a power calibration area (abbreviated as “PCA”) on the innermost circumference of the optical disc.
The optimum recording power is determined by performing OPC for trial writing while changing step by step.

[0003] CD-RW, CD-R, and DV
In a recording medium such as a D-RW, the recording power to be applied to a laser light source differs for each type of the medium. In an information recording apparatus capable of recording information on a plurality of types of recording media, the medium It is necessary to change the laser emission drive current applied to the laser light source every time according to the type of the laser light source.

As described above, the information recording apparatus requires control for setting an optimum recording power when recording information on a recording medium, but conventionally, a laser emission driving current is supplied to a laser light source. Setting a predetermined value in a laser driver (laser control unit) that performs laser control, and calculating an optimum recording power value assuming that laser light corresponding to the predetermined value is emitted from a laser light source; or The laser adjustment is performed so that the calculation can be performed on the assumption (for example, see Japanese Patent Application Laid-Open No. 7-129961).

[0005]

However, in the above-described conventional information recording apparatus, the recording power output by the OPC is converted from the value set by the laser control unit (that is, the recording power is output from the OPC).
The setting value for the laser control unit is fixedly calculated based on the design specifications and adjustment of the laser control unit), and the optimum recording power value is calculated by processing such as the γ method or the β method. Even if a constant laser emission drive current is applied to the laser light source, such as when the laser light has deteriorated over time, or when the media characteristics of the optical disc and the characteristics of the laser light source have changed due to high temperature during information recording. If the amount of laser light changes, there is a problem that the optimum recording power value cannot be calculated accurately.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the laser light emitted from a laser light source is deteriorated with the passage of time, or a high temperature state occurs at the time of information recording, and the media characteristics of the optical disk and the It is an object of the present invention to always output a desired amount of laser light from a laser light source even when the characteristics of the light source fluctuate.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention irradiates a recording medium with a laser beam generated from a laser light source based on a light quantity and a light emission pattern to record and reproduce information. In the recording apparatus, a laser emission drive current supply unit that supplies a laser emission drive current according to the light quantity and the emission pattern to the laser light source, and receives the laser light generated from the laser light source and adjusts the light quantity of the laser light. A light quantity measuring means for measuring, and before recording information on the recording medium, a laser light emission drive current supplied by the laser light emission drive current supply means and a light quantity measured by the light quantity measurement means when the laser light emission drive current is supplied. The laser emission drive current that calculates and stores the relationship information of
It is provided with a light amount related information calculation storage means.

In the information recording apparatus described above, the laser light emission drive current / light amount relation information calculation storage means stores the light amount exceeding the steady light emission threshold and the light amount when the light amount is measured. It is preferable to provide a means for calculating the relation information based on the laser emission drive current. Further, in the information recording apparatus as described above, the laser light emission drive current / light amount relationship information calculation storage means uses the laser light emission drive current and the light amount measured at the time of supply of the laser light emission drive current in a plurality of relations. Means for calculating information in a linear format may be provided.

In the above information recording apparatus, the laser emission driving current / light amount relationship information calculating and storing means stores the laser emission driving current / light amount so as to cause the laser light source to emit a constant amount of light when calculating the relationship information. Means for controlling the supply of the laser emission drive current by the supply means may be provided. Further, in the information recording apparatus as described above, the laser light emission drive current / light amount relation information calculation / storage means is configured not to irradiate the recording area of the recording medium with the laser light at the time of calculating the relation information. It is preferable to provide means for controlling the light amount of the laser light from the laser light source by the means.

Further, in an information recording method for recording and reproducing information by irradiating a recording medium with a laser beam generated based on a light amount and a light emission pattern from a laser light source, it is preferable that the information is recorded on the recording medium before the information is recorded. Supplying a laser emission drive current according to the light quantity and the emission pattern to the laser light source,
The laser light generated from the laser light source is received, the light amount of the laser light is measured, and the relation information between the supplied laser emission driving current and the measured light amount at the time of supplying the laser emission driving current is calculated. A method for recording information to be stored is also provided.

In the above information recording method, the relation information is calculated based on a light amount exceeding a steady light emission threshold among the measured light amounts and a laser emission drive current when the light amount is measured. Good. In the information recording method as described above, the relation information may be calculated in a linear format using a plurality of the laser emission driving currents and the light amounts measured when the laser emission driving currents are supplied.

Further, in the information recording method as described above, it is preferable that the supply of the laser emission drive current is controlled so that the laser light source emits light at a constant light amount when the relation information is calculated. Furthermore, in the information recording method as described above, when calculating the related information, control is performed so that the recording area of the recording medium is not irradiated with the laser light so as to measure the amount of laser light from the laser light source. Good.

[0013]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 1 is a functional block diagram showing a configuration of an optical disk recording control device (optical disk drive device) according to an embodiment of the present invention.
1 shows a main part according to the present invention. In FIG. 1, solid arrows indicate the direction of data, and wavy arrows indicate control signals (commands).
, And a thick arrow from the drive motor 11 to the pickup unit 2 indicates the direction of drive control. The optical disk medium 20 is an optical disk such as a CD-R or CD-RW on which information (data) is recorded based on the intensity of a laser beam emitted from the pickup unit 2 and a light emission pattern. The optical disk medium 20 is rotated by the spindle drive unit 1 and has a circular recording groove called a track formed on the recording surface from the inner periphery to the outer periphery.

A pickup unit (PU unit) 2 is provided with a laser light source (Laser) for emitting a laser beam to the optical disk medium 20.
r Diode (LD) 3 and a rear PD (Photo Detector) 5 for receiving the reflected light that is reflected by the laser light from the LD 3 and returned to the optical disk medium 20.
The data is recorded or reproduced while following the track. The PU unit 2 also includes a front PD 4 that receives the laser light emitted from the LD 3 before reflection. The optical signal of the laser beam received by the front PD 4 and the rear PD 5 is passed as an electrical signal to the analog signal processor 9 for processing.
The optical signal received by the front PD 4 at the time of data recording becomes a digital numerical value representing the amount of light emitted by the A / D conversion block unit 10 via the analog signal processing unit 9.

At the time of data reproduction, the optical signal received by the rear PD 5 is transmitted to the data demodulation unit 12 via the analog signal processing unit 9.
And is converted to user data. The user data is temporarily stored in the RAM 14 and passed to the host computer through an external interface (not shown). On the other hand, data to be recorded is stored in a RAM 14 having a function as a data buffer from a host computer (not shown) through an external interface. After that, the data is converted into pit format data for recording by the data modulating unit 7 and further sent to the laser control unit 6 to apply a current of a pulse light emission pattern to the LD 3 of the PU unit 2 so that the laser beam is irradiated and recorded. You.

The system controller 15 issues a control command instructing switching of data and signal processing to other block units directly or indirectly and at a proper timing, so that a series of operations between each block unit can be performed. The above-described control operation is realized, and overall control of the entire optical disk recording control device is performed. A control procedure by the system controller 15 between the laser control unit 6, the analog signal processing unit 9, and the light quantity acquisition unit 8 including the A / D conversion block unit 10 has a feature according to the present invention. The system controller 15 stores the control procedure as a program in the RO.
It operates by transmitting and receiving data to and from the M13 and the RAM 14 as a work area. The system controller 15, the ROM 13, the RAM 14, the data modulator 7, and the data demodulator 12 are communicably connected to each other by a bus 16 for exchanging data and control.

That is, this optical disk recording control device corresponds to an information recording device that records and reproduces information by irradiating a recording medium with a laser beam generated from a laser light source based on a light amount and a light emission pattern. The laser control unit 6 functions as a laser emission drive current supply unit that supplies the laser light source with a laser emission drive current according to the light amount and the emission pattern. The front PD 4 and the light quantity acquisition unit 8 function as light quantity measuring means for receiving the laser light generated from the laser light source and measuring the light quantity of the laser light.
The system controller 15 compares the laser emission drive current supplied by the laser emission drive current supply unit with the light amount measured by the light amount measurement unit when the laser emission drive current is supplied before recording the information on the recording medium. It functions as a laser emission drive current / light amount relationship information calculation storage unit that calculates and stores relationship information.

Further, the system controller 15 includes:
Means for calculating the relational information based on the light amount exceeding the steady light emission threshold among the measured light amounts and the laser light emission drive current when the light amount is measured; and the laser light emission drive current and the laser light emission drive current Means for calculating the relationship information in a linear form by using a plurality of light amounts measured at the time of supply, and a laser by the laser emission drive current supply means so as to cause the laser light source to emit a constant amount of light when calculating the relationship information. Means for controlling the supply of the light emission drive current;
When calculating the related information, the function of controlling the light amount measuring means to control the light amount of the laser light from the laser light source so as not to irradiate the recording area of the recording medium with the laser light.

Next, a control process according to the present invention performed in setting the laser power by changing the type of the OPC or the optical disk medium in the optical disk recording control device shown in FIG. 1 will be described. FIG. 2 is a flowchart showing a laser emission drive current / light amount relationship information calculation storage control process in the optical disk recording control device shown in FIG. FIG. 3 is a diagram showing a general relationship between a laser emission driving current applied to a laser light source (semiconductor laser) and an emitted light amount.

As shown in FIG. 2, the system controller 15 performs the processing according to the first and sixth aspects of the present invention.
Before recording the actual data on the optical disk medium 20,
In step (indicated by "S" in the figure) 1, a preset value (initial value) of a predetermined laser emission drive current is set in the laser control unit. Then, in step 2, the PU unit is set to the recording state.
In step 3, the laser light emitted from the LD in the PU unit is also received by the front PD in the PU unit, processed by the analog signal processing unit and the A / D conversion block unit, and the light emission amount (light amount) is acquired. Perform sampling processing.

Next, it is determined whether or not the light quantity acquired in step 4 exceeds a preset LD threshold (steady light emission threshold). The LD threshold is a threshold light emission amount (Pth) of the LD as shown in FIG.
It is known that when a laser emission drive current exceeding th) is applied, steady emission occurs. If the value of the sampled light amount does not exceed the threshold light emission amount (Pth) of the LD in the judgment of step 4, it is excluded from the sampling value and the process proceeds to step 6. Then, the number of times of sampling is incremented by 1, and the process proceeds to step 6.

In step 6, it is determined whether or not the number of times of sampling exceeds a predetermined number. At this time, the predetermined number may be arbitrarily set to a value of 2 or more. If it is determined in step 6 that the number of samplings does not exceed the predetermined number, the process returns to the first step 1, and the laser light emission drive current value different from the previous one is set, and the light amount sampling is repeated. If the number exceeds the predetermined number, the process proceeds to step 7 where a relational expression is calculated as relational information between the laser emission drive current and the light amount and stored in the RAM. For calculating the relational expression, a known technique such as an approximation method may be used as long as data of a set of sampling values is referred to. As described above, an accurate output light power can be set in the next actual recording using the relational expression between the laser emission drive current and the light amount obtained in step 7.

In the control processing according to the second and seventh aspects of the present invention, the laser emission drive is performed by omitting a sample at a position deviating from the actual light emission amount so as not to emit light in a steady state in the determination processing of the step 4. The relational expression between the set value of the current and the light amount of the laser beam can be obtained more easily. Further, as the control processing according to claims 2 and 7 of the present invention, since the applied current and the light quantity are substantially linear as shown in FIG. From the sample values at two or more points, the relational expression between the power setting value and the light amount in the laser control unit 6 can be easily determined by a linear expression. The process of step 2 may be controlled and executed prior to the process of step 1, and the light amount may be sampled while changing the set value in the recording state.

Next, in the multi-pulse recording, which is the usual recording method conventionally used in the above processing, the power may fluctuate at high speed and sampling may be difficult. In the control process according to the fourth and ninth aspects, when calculating the above relational expression, the laser emission drive is performed by the system controller 15 so that the laser control unit 6 causes the LD 3 to enter a DC emission state in which the LD 3 emits light at a constant power (a constant light amount). By controlling the current supply, it is possible to easily obtain the light emission amount if the light emission is performed at a constant power.

Next, claim 5 and claim 10 of the present invention.
For example, when calculating the above relational expression, the system controller 15 moves the PU unit 2 by the drive motor 11 so that at least the optical disk medium 2
Sampling is performed by moving the recording area 0 to a position where light is not irradiated. Alternatively, defocus may be performed sufficiently so as not to form a mark even in the recording area, or the focus servo may be turned off. In this way, the emitted light at the recording level does not converge on the recording area of the optical disc medium 20, so that the PC
The above relational expression can be obtained without using a special area such as A and without destroying the area.

Since this optical disk recording control device calculates and stores the relational expression between the laser emission drive current and the amount of laser light before data recording, the laser light emitted from the laser light source in the next actual recording is performed. Even if the optical disk deteriorates over time or becomes high temperature during information recording and the media characteristics of the optical disk or the characteristics of the laser light source fluctuate, the emitted light power (recording power) of the laser light can be accurately determined based on the relational expression. Can be set. In addition, when calculating the relational expression, a sample value of the light amount at a position deviating from the actual light emission amount that does not cause steady light emission is omitted, so that the relational expression between the set value of the laser light emission drive current and the light amount of the laser light is improved. It can be easily obtained.

Further, since the current applied to the LD and the light quantity are substantially linear when the current is equal to or greater than the threshold value, the relational expression between the laser emission drive current and the light quantity in the laser control unit based on the sample values at two or more points. Can be easily calculated by a linear equation. In addition, since the light emission is performed at a constant power when sampling the light emission amount of the laser light, an accurate light emission amount can be easily obtained. Further, since the emitted light at the level to be recorded does not converge on the recording area of the optical disk medium, the above relational expression can be obtained without using a special area such as PCA or destroying the area.

[0028]

As described above, according to the information recording apparatus and the information recording method of the present invention, the laser light emitted from the laser light source deteriorates with the passage of time or the temperature becomes high during the information recording. Even when the media characteristics of the optical disk and the characteristics of the laser light source fluctuate, the laser light source can always output a desired amount of laser light.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of a portion related to the present invention of an optical disk drive device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a laser emission drive current / light amount relationship information calculation storage control process in the optical disc recording control device shown in FIG. 1;

FIG. 3 is a diagram showing a general relationship between a laser emission drive current applied to a laser light source (semiconductor laser) and an emitted light amount.

[Explanation of symbols]

 1: spindle drive section 2: pickup section 3: laser light source (LD) 4: front PD 5: rear PD 6: laser control section 7: data modulation section 8: light quantity acquisition section 9: analog signal processing section 10: A / D Conversion block unit 11: Drive motor 12: Data demodulation unit 13: ROM 14: RAM 15: System controller 16: Bus 20: Optical disk medium

Claims (10)

[Claims] 1. An information recording apparatus for recording and reproducing information by irradiating a recording medium with a laser beam generated based on a light amount and a light emission pattern from a laser light source, wherein the laser light source responds to the light amount and the light emission pattern. A laser emission drive current supply unit for supplying the laser emission drive current, a light amount measurement unit for receiving the laser light generated from the laser light source and measuring the amount of the laser light, and recording information on the recording medium. A laser light emission drive current and a light amount for calculating and storing relation information between the laser light emission drive current supplied by the laser light emission drive current supply means and the light quantity measured by the light quantity measurement means at the time of supply of the laser light emission drive current; An information recording device comprising a relation information calculation storage means. 2. The information recording apparatus according to claim 1, wherein the laser light emission drive current / light amount relation information calculation storage means stores the light amount exceeding a steady light emission threshold and the light amount among the measured light amounts. An information recording device provided with means for calculating the relation information based on the laser emission drive current. 3. The information recording apparatus according to claim 1, wherein the laser emission drive current / light quantity relationship information calculating and storing means stores the laser emission drive current and the quantity of light measured when the laser emission drive current is supplied. An information recording apparatus, comprising: means for calculating the relationship information in a linear format using a plurality of pieces. 4. The information recording apparatus according to claim 1, wherein the laser light source is controlled to have a constant light amount when calculating the relation information. An information recording apparatus, comprising: means for controlling supply of a laser emission drive current by the laser emission drive current supply means so as to emit light. 5. The information recording apparatus according to claim 1, wherein said laser light emission drive current / light amount relation information calculation storage means stores said relation information in a recording area of said recording medium when said relation information is calculated. An information recording apparatus, comprising: means for controlling so as not to irradiate the laser light so that the light quantity measuring means measures the light quantity of the laser light from the laser light source. 6. An information recording method for recording and reproducing information by irradiating a recording medium with a laser beam generated based on a light amount and a light emission pattern from a laser light source, wherein: before recording information on the recording medium, A laser emission driving current is supplied to the laser light source in accordance with the light intensity and the light emission pattern, a laser light generated from the laser light source is received, the light intensity of the laser light is measured, and the supplied laser emission driving current and An information recording method, comprising calculating and storing information relating to the measured light amount when the laser emission drive current is supplied. 7. The information recording method according to claim 6, wherein the relation information is calculated based on a light amount exceeding a steady light emission threshold among the measured light amounts and a laser light emission drive current when the light amount is measured. An information recording method, comprising: 8. The information recording method according to claim 6, wherein the relation information is calculated in a linear form by using a plurality of the laser emission drive currents and light amounts measured when the laser emission drive currents are supplied. The information recording method characterized by the above-mentioned. 9. The information recording method according to claim 6, wherein supply of the laser emission drive current is controlled so that the laser light source emits light at a constant light amount when calculating the related information. An information recording method, characterized in that: 10. The information recording method according to claim 6, wherein at the time of calculating the related information, the recording area of the recording medium is not irradiated with the laser light so that the laser light from the laser light source is not irradiated. An information recording method, comprising controlling to measure the amount of laser light.