JP3574430B2 - Optical disk recording and playback device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk recording and reproducing apparatus capable of recording data on an optical disk such as a CD-R or CD-RW.
[0002]
[Prior art]
As an optical disk recording / reproducing device for recording data on an optical disk, a compact disc-recordable (CD-R) device and a compact disc-rewritable (CD-RW) device are known.
[0003]
When writing data to an optical disk, the rotation of the optical disk is controlled by the so-called CLV (Constant Liner Velocity) method, which keeps the writing linear velocity constant so that the density of the written pits is constant, and the writing is performed. I have been. In the CLV method, in order to keep the linear velocity constant, the rotation speed increases when writing on the inner circumference side of the optical disc, and decreases as it moves toward the outer circumference side of the optical disc.
On the other hand, in recent optical disk recording / reproducing apparatuses, it is desired that data be written to the optical disk at a higher speed than in the past. The rotation speed becomes too high, and there is a problem that data cannot be reliably written on the inner peripheral side.
[0004]
Therefore, an optical disk recording / reproducing apparatus controlled by a zone CLV control method has been developed in order to shorten the writing time of the entire optical disk without increasing the rotation speed on the inner peripheral side of the optical disk and increase the writing speed as a whole.
In the zone CLV method, writing is performed at a constant low linear velocity on the inner peripheral side of the optical disk. Therefore, the rotational speed on the inner peripheral side is the same as that in the related art. This is a method of increasing the speed and increasing the rotation speed to increase the writing speed of the entire optical disc.
[0005]
FIG. 7 shows an example of writing by the zone CLV method.
In this example, writing is performed at 16 × speed on the inner circumference side of the optical disc 10, writing is performed at 20 × speed when moving to the outer circumference after elapse of a predetermined time, and writing is performed at 24 × speed after moving to the outer circumference after elapse of the predetermined time.
By adopting the zone CLV method, the inner peripheral side of the optical disk 10 rotates at the conventional rotational speed, so that no writing error occurs on the inner peripheral side, and the writing speed can be increased as a whole.
[0006]
The optical disk recording / reproducing apparatus performs a data writing test (so-called OPC (Optimum Power Control)) in a PCA area (see reference numeral 9 in FIG. 7) located at the innermost periphery of the recording surface of the optical disk when writing data to the optical disk. ) To set the power of the laser beam at the time of writing to an appropriate value.
Hereinafter, the power setting of the laser beam in the optical disk recording / reproducing apparatus will be described.
The optical disk recording / reproducing device first reads the ATIP from the optical disk. ATIP is where optical disk manufacturers record optical disk information.
The optical disc recording / reproducing apparatus reads out the optimum laser power value from a preset data table based on the information of the optical disc, and gradually increases the power of the laser light around the read optimum laser power value. Perform trial writing. The test-written data is read, and the vertical contrast (asymmetry: hereinafter, sometimes referred to as vertical contrast β) of the read light intensity waveform is confirmed. By confirming the vertical contrast, the laser power at the time of the best vertical contrast is set as the optimum laser power value of the optical disc.
[0007]
[Problems to be solved by the invention]
As described above, in the optical disk recording / reproducing apparatus, the OPC is performed in the innermost PCA area of the optical disk to set the optimum value of the laser power.
However, in the optical disk recording / reproducing apparatus adopting the zone CLV method, the linear velocity is increased on the outer peripheral side of the optical disk, so that the output value of the laser beam initially set in the PCA area is not the optimum power value. There is a problem that it cannot be said.
That is, in the example shown in FIG. 7, the laser power value is set at 16 times speed in the case of OPC, but when writing reaches the outer circumference of the optical disk, the linear speed becomes 20 times speed or 24 times speed, The optimum laser power value is different from the case where the laser speed is set at 16 times speed, and the higher the linear velocity, the more power is required.
[0008]
In such a case, even if the laser power deviates from the optimum laser power, it is not so large that writing cannot be performed. Therefore, it is possible to continue writing without changing the laser power as it is.
However, since writing is not performed with the optimum laser power, the quality and reliability of the written data may be reduced, for example, the data cannot be read when the written data is read.
[0009]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an optical disc recording / reproducing apparatus capable of optimizing a laser power when writing data to an optical disc by a zone CLV method. It is in.
[0010]
[Means for Solving the Problems]
That is, according to the optical disk recording / reproducing apparatus of the present invention, the optical disk recording / reproducing is controlled by the zone CLV system in which the linear velocity at the time of writing is increased stepwise toward the outer peripheral side of the optical disk so that writing is possible. In the apparatus, a laser diode for irradiating a laser, laser control means for controlling a laser power of the laser diode to increase by a preset correction value when increasing a linear velocity at the time of writing, and the correction value Storage means for storing in advance, the correction value is a low temperature based on the magnitude of the linear velocity after increasing the linear velocity, the type of optical disc mounted, and the temperature state during the OPC operation , A value preset in each of combinations of temperature states classified into three stages of high temperature and high temperature as a data table. The laser control means reads the ATIP information of the optical disc when the optical disc is loaded, specifies the type of the loaded optical disc, and changes the laser power in the OPC operation while changing the laser power. The vertical symmetry β of the waveform is measured, the change amount k of the vertical symmetry β with respect to the change amount of the laser power is calculated, and the change amount k of the vertical symmetry β is stored in advance and has a relationship of x <y. By comparing two predetermined values x and y, the temperature state is low when k> y, the temperature state is normal when x <k <y, and the temperature state when k <x. Is determined to be a high temperature, the linear velocity after the linear velocity is increased, the type of the optical disk specified when the optical disk is mounted, and a correction value that is compatible with all of the temperature states determined during the OPC operation. From the storage means Out look is characterized by controlling so as to increase the laser power of the only laser diode readout correction value.
[0011]
The operation by adopting this configuration is as follows.
That is, since the laser power is changed each time the linear velocity at the time of writing is changed by the zone CLV control, the quality and reliability of the written data can be improved as compared with the related art.
In addition, although there are various manufacturers and various types of optical disks, it is possible to change the laser power to a laser power suitable for each of them, so that higher quality and more reliable data can be provided.
Furthermore, considering the characteristic of the laser diode that the output value varies depending on the temperature state even when the voltage value applied to the laser diode is constant, the magnitude of the correction value can be selected according to the temperature state. Laser power can be maintained at an appropriate value. For this reason, data with higher quality and higher reliability can be provided.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
First, FIG. 1 shows an explanatory diagram of a first embodiment of an optical disk recording / reproducing device (hereinafter, may be simply referred to as an optical disk device), and an operation principle will be described.
FIG. 1 is a graph in which the horizontal axis represents the writing time when writing data to one optical disk, and the vertical axis represents the laser power during writing data.
As described in the related art, when data is written on an optical disk by the zone CLV method, the linear velocity is increased stepwise.
In the present embodiment, first, data is written at 16 times speed. The laser power at this time is P1. P1 is a value determined by OPC before writing data.
[0013]
After a lapse of time t1 from the start of data writing, the linear velocity is switched to 20-times velocity. At this time, the laser power is also switched to the power adjusted to 20 times speed. It is assumed that the laser power at this time is P2. The switching of the laser power is performed such that a preset correction value α is added to P1.
[0014]
Further, after a lapse of time t2 from the start of data writing, the linear velocity is switched to 24 times speed. At this time, the laser power is also switched to the power corresponding to the 24 × speed. It is assumed that the laser power at this time is P3. The switching of the laser power is performed such that a preset correction value γ is added to P2.
[0015]
Since the optical disk device operates as described above, even if the linear velocity increases stepwise, the laser power is also increased stepwise in accordance with the linear velocity, and data can be written with an appropriate laser power value.
[0016]
Next, FIG. 2 shows a block diagram of the internal structure of the optical disk device, and the configuration of the device of the present embodiment will be described based on the block diagram.
The optical disk device 30 is a device that can write data on a CD-R or CD-RW as an example of an optical disk.
[0017]
The optical disc device 30 includes a laser diode 12 (hereinafter, sometimes simply referred to as an LD) that oscillates a laser beam for irradiating the optical disc 10, a laser driver 14 that supplies a drive current for driving the LD 12 to the LD 12, and a laser driver 14 (Auto Power Control) circuit 16 for controlling the voltage of the APC.
The LD 12 is built in the optical pickup 11 and moves from the inner peripheral side to the outer peripheral side of the optical disk 10 together with the optical pickup 11 to write data on the optical disk 10. The LD 12 is connected to a laser driver 14, and its laser power is controlled by current control by the laser driver 14.
An APC circuit 16 is connected to the laser driver 14. The APC circuit 16 adjusts the voltage applied to the laser driver 14 so that a constant laser power is output so that the set laser power value does not fluctuate.
[0018]
Light reflected from the optical disk 10 is input to the RF amplifier 18 as a reflected signal via a detector (not shown) and is amplified.
The reflection signal from the optical disk 10 input to the RF amplifier 18 is input to the servo processor 20. The servo processor 20 performs servo control such as rotation of the spindle motor 22 and focusing and tracking of an optical pickup (not shown) based on the reflection signal.
[0019]
The CPU 24 receives the reflection signal from the RF amplifier 18 and controls the APC circuit 16. Here, the operation of the CPU 24 as described below is performed based on a control program, and such a control program is stored in advance in a memory (not shown) as firmware.
A storage means 26 such as a ROM is connected to the CPU 24. A data table A is constructed in the storage means 26.
The CPU 24 reads the data stored in the data table A, and based on this data, can set the laser power at the time of OPC and change the laser power when the linear velocity is changed.
In the present embodiment, the laser driver 14, the APC circuit 16, and the CPU 24 constitute a laser control unit 28.
[0020]
The contents of the data table A will be described.
The contents of the data table A are preset before shipment of the optical disk device 30. In the data table A, an optimum value P0 (Company A to each company) of the laser power when OPC is first performed is stored in correspondence with the type of the optical disc. P0 is an optimum laser power value used as a reference when performing OPC, and writing is not actually started with this value P0. Since the operation of the OPC has been described in the related art, the description is omitted here. However, in the OPC, a writing test is performed based on P0, and the control laser power P1 is calculated when actually writing.
Here, the value of P0 is shown only for different manufacturers, but it is obvious that the value of P0 differs depending on the type of optical disk even if the manufacturer is the same. However, FIG. 2 shows only each maker, and the case where the maker is the same but the type is different and the value of P0 is different is omitted.
[0021]
In the data table A, a correction value α to be added to the laser power P1 when the linear velocity is changed by the operation of the zone CLV is set in advance corresponding to the type of each optical disc. The value obtained by adding the correction value α to the laser power P1 is P2 (see FIG. 1).
Further, a correction value to be further added from the laser power P2 is γ.
The value obtained by adding the correction value γ to the laser power P2 is P3 (see FIG. 1).
The correction value α and the correction value γ are set in advance and recorded in the data table A before shipment of the optical disk device.
These correction values α and γ also show only different values for each maker. However, even if the maker is the same, some correction values are different depending on the type of optical disk. However, like P0, it is not shown here.
[0022]
How the optical disc device 20 is controlled based on the contents of the data table A will be described with reference to the flowchart of FIG.
First, in step S100, when the optical disk 10 is loaded to write data, the optical pickup 11 reads the ATIP previously written on the optical disk by the optical disk manufacturer.
The CPU 24 that has read the ATIP reads the appropriate laser power value P0 recorded in the data table A and corresponding to the type of the mounted optical disc.
The CPU 24 executes OPC based on the read value of P0, and sets a laser power value P1 when data is first written.
[0023]
In the next step S102, the CPU 24 starts writing data at the set laser power value P1.
Next, in step S104, if the speed is not changed, writing is continued with the laser power as it is, and if the speed is changed, the process proceeds to step S106.
[0024]
In step S106, the CPU 24 reads out the correction value corresponding to the type of the mounted optical disk recorded in the data table A. At this time, the correction value α is read when the speed is changed from 16 × to 20 ×, and the correction value γ is read when the speed is changed from 20 × to 24 ×.
Although the correction value α and the correction value γ differ depending on the type of the optical disk, the type of the optical disk is determined when the ATIP is first read, so that the correction value α and the correction value γ can be obtained from the data table A based on this. The CPU 24 that reads the data changes the laser power by controlling the APC circuit 16 so that the correction value read from the data table A is added to the value of the laser power emitted before the speed change.
[0025]
Then, in step S108, the process ends when all data writing is completed.
[0026]
Next, the operation principle of the second embodiment of the present invention will be described.
The present embodiment is characterized in that the value of the correction value added to the laser power can be set according to the temperature state at that time.
That is, as a characteristic of the laser diode, the laser diode is output only at a power lower than the set laser power when the temperature is high, and is output at a power higher than the set laser power when the temperature is low.
Therefore, when the linear velocity during the zone CLV control is changed, the laser power is not increased by always adding a constant correction value, but is changed according to the temperature at that time (in the present embodiment, during the OPC operation). If the correction value is added, writing can be performed with a more appropriate laser power, and the quality of data written to the optical disc can be improved.
[0027]
In the present embodiment, the correction values are divided into three stages according to the temperature state at that time, and the corresponding correction values are set in advance at low, normal, and high temperatures.
However, the division of the correction value according to the temperature condition is not limited to three stages, and may be set according to a more detailed temperature condition. Furthermore, the correction value may not be set for each temperature step, but may be set according to the temperature at that time.
[0028]
FIG. 4 illustrates how the correction value is set according to the temperature change.
The graph shown in FIG. 4 shows that when determining the laser power at the time of the OPC operation, the laser power is changed from P01 to P02 around the optimum laser power value P0, and the vertical contrast β of the reflected light waveform is changed. It is what is being measured.
As described in the prior art, in order to set the laser power at the time of writing, first, the optimum laser power value P0 is read from the data table, and a test write is performed in the PCA area of the optical disk while changing the power centering on P0, The power corresponding to the optimum vertical contrast β previously stored in the data table is defined as P1, and this P1 is used as a laser power value to write data on the optical disk.
[0029]
In the present embodiment, the amount of change in the vertical contrast β when the laser power is changed, that is, the slope in FIG. 4 is measured, and the temperature condition at that time is determined based on the slope.
That is, it has already been found that the inclination of the up-down contrast β when the laser power is changed becomes larger at a low temperature than at a normal time, and becomes smaller at a high temperature than at a normal time.
Therefore, in this embodiment, the temperature state is measured by measuring the amount of change in the vertical contrast β when the laser power is changed during the OPC operation.
[0030]
Here, when the inclination in FIG. 4 is k, and when the laser power is changed from P01 to P02, the up-down contrast β changes from β01 to β02,
k = β02-β01 / P02-P01
Then, the slope k is calculated.
Here, k is compared with predetermined comparison values x and y. The comparison values x and y are set in advance and stored in storage means such as a memory.
If k> y, it is determined that the temperature is low. If x <k <y, it is determined that the temperature is normal. If k <x, it is determined that the temperature is high. Is done.
[0031]
Next, FIG. 5 is a block diagram showing the internal configuration of the optical disk device according to the second embodiment, and the configuration of the optical disk device will be described.
Note that the same reference numerals are given to the components described in the above-described embodiment, and the description is omitted. Therefore, only the data table B constructed in the storage unit 32 will be described here.
The data table B is set before shipment of the optical disk device 30. The data table B stores an optimum value P0 (Company A to each company) of the laser power when the OPC is first performed, corresponding to the type of the optical disc. P0 is an optimum laser power value to be a reference when performing OPC.
[0032]
In the data table B, a correction value α to be added to the laser power P1 when the linear velocity is changed by the operation of the zone CLV is set in advance in accordance with the type of each optical disc.
The correction value α is provided in three stages from α1 to α3 depending on the temperature. That is, any one of the correction values α1 to α3 is adopted depending on the temperature state determined by measuring the change amount of the upper and lower contrast β when the laser power is changed during the OPC operation.
The value obtained by adding the correction value α1 or α2 or α3 to the laser power P1 is P2 (see FIG. 1).
[0033]
Further, a correction value to be further added from the laser power P2 is γ.
The correction value γ is also provided in three stages from γ1 to γ3 depending on the temperature. That is, one of the correction values γ1 to γ3 is adopted depending on the temperature state determined by measuring the change amount of the upper and lower contrast β when the laser power is changed during the OPC operation.
It is assumed that the correction values α and γ are set in advance and recorded in the data table B before shipment of the optical disk device.
[0034]
Next, how the optical disc device 20 of the second embodiment is controlled based on the contents of the data table B will be described with reference to the flowchart of FIG.
First, in step S200, when the optical disk 10 is loaded to write data, the optical pickup 11 reads the ATIP previously written on the optical disk by the optical disk manufacturer.
The CPU 24 that has read the ATIP reads the appropriate laser power value P0 recorded in the data table B and corresponding to the type of the mounted optical disc.
The CPU 24 executes OPC based on the read value of P0, and sets a laser power value P1 when data is first written.
[0035]
Next, in step S202, the CPU 24 calculates a change amount (slope) k of the up-down contrast β when the laser power is changed.
The CPU 24 determines the current temperature based on k and predetermined determination values x and y. Here, if x <y, if k> y, it is determined that the temperature is low. If x <k <y, it is determined that the temperature is normal. If k <x, the temperature is low. Is determined to be at a high temperature.
In the subsequent step S204, the CPU 24 starts writing data at the set laser power value P1.
Next, in step S206, if the speed is not changed, writing is continued with the same laser power, and if the speed is changed, the process proceeds to step S208.
[0036]
In step S208, the CPU 24 reads a correction value corresponding to the type of the mounted optical disc recorded in the data table B. Based on the temperature determined in step S202, one of the correction values α1 to α3 is selected when changing the speed from 16 × to 20 ×, and the correction value is used when changing the speed from 20 × to 24 ×. One of γ1 to γ3 is selected.
The CPU 24 controls the APC circuit 16 so that the correction value read from the data table B is added to the value of the laser power irradiated before the speed change, and changes the laser power.
[0037]
Then, in step S210, the process ends when all data writing is completed.
[0038]
Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the embodiments, and it is needless to say that many modifications can be made without departing from the spirit of the invention. .
[0039]
【The invention's effect】
According to the optical disc recording / reproducing apparatus according to the present invention, when the linear velocity at the time of writing is changed stepwise, the laser power for writing is controlled to be increased by a preset correction value, At this time, it is suitable for various manufacturers and types of optical discs, and it is possible to accurately judge the temperature condition and raise the temperature by a correction value suitable for the temperature condition. And reliability can be increased.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram illustrating an operation of an optical disc recording / reproducing apparatus according to the present invention.
FIG. 2 is a block diagram for explaining a configuration of a first embodiment of an optical disc recording / reproducing apparatus according to the present invention.
FIG. 3 is a flowchart illustrating a laser power control method of the optical disc recording / reproducing apparatus according to the present invention.
FIG. 4 is an explanatory diagram for determining a temperature condition in a second embodiment of the optical disc recording / reproducing apparatus according to the present invention.
FIG. 5 is a block diagram illustrating a configuration of a second embodiment of the optical disc recording / reproducing apparatus according to the present invention.
FIG. 6 is a flowchart for explaining an operation of a second embodiment of the optical disc recording / reproducing apparatus according to the present invention.
FIG. 7 is an explanatory diagram illustrating a zone CLV method.
[Explanation of symbols]
9 PCA area 10 Optical disk 11 Optical pickup 12 Laser diode 14 Laser driver 16 APC circuit 18 RF amplifier 20 Servo processor 22 Spindle motor 24 CPU
26, 32 storage means 28 laser control means 30 optical disk recording / reproducing apparatus

Claims (1)

In an optical disc recording / reproducing apparatus controlled by a zone CLV system in which the linear velocity at the time of writing is increased stepwise toward the outer peripheral side of the optical disc to enable writing,
A laser diode for irradiating a laser,
When increasing the linear velocity at the time of writing, laser control means for controlling the laser power of the laser diode to increase by a preset correction value,
Storage means for storing the correction value in advance,
The correction value is determined based on the magnitude of the linear velocity after the linear velocity is increased, the type of the loaded optical disc, and the temperature state during the OPC operation. Values set in advance by the combination are stored in the storage means as a data table,
The laser control means,
When the optical disk is mounted, the type of the mounted optical disk is specified by reading the ATIP information of the optical disk,
In the OPC operation, the vertical symmetry β of the reflected light waveform is measured while changing the laser power, the change amount k of the vertical symmetry β with respect to the change amount of the laser power is calculated, and the change amount k of the vertical symmetry β is calculated. Is compared with two predetermined values x and y which are stored in advance and have a relation of x <y, so that if k> y, the temperature state is low, and if x <k <y, the temperature state is low. If the state is usually k <x, it is determined that the temperature state is high,
From the storage means, a correction value suitable for all of the magnitude of the linear velocity after the linear velocity was increased, the type of the optical disk specified at the time of mounting, and the temperature state determined at the time of the OPC operation was read out. An optical disc recording / reproducing apparatus which controls so as to increase the laser power of a laser diode by a correction value.

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