JPH09171632A - Recording power correction device for optical disk recorder and optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct recording power excellently forming a recording mark even when dust, scratch, finger mark, etc., exist on a disk surface, to control a laser so as not to emit light with excess power and to protect the laser by variably controlling target power in recording power. SOLUTION: The disk 51 is provided with an abnormal area imitating dust sticking to the test write area. The data on the disk 51 are reproduced by a data reproducing circuit 62 through a pickup 2 and read by a controller 65. Simultaneously, the level decline amount S7 of an RF signal detected by a level measurement circuit 61 is read by the controller 65 also. A recording power correction amount for the signal S7 is stored in a correction amount table 63, and the contents can be set by the controller 65. The correction amount from the correction amount table 63 and the recording power correction amount outputted from the controller 65 are switched by a selector 64. Then, when the RF signal level is lowered due to dust, etc., at the time of data recording, the power thereof is corrected by the recording power correction amount.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk recording apparatus for condensing a light beam on a recording surface of an optical disk to form a recording mark, and more particularly to a recording power correction apparatus and an optical disk for assisting the recording power correction. Regarding

[0002]

2. Description of the Related Art Recording power is controlled based on the intensity of a return laser beam (reflected light) when a pit is actually formed by a recording laser beam, so that optimum recording can be performed due to variations in the sensitivity of the medium and inclination. A control method is known in which recording can be performed with a laser power so that an optimum pit is always formed even if the power changes (JP-A-4-1).
No. 0237). In an optical disk recording apparatus that forms a recording mark by converging a light beam on the recording surface of an optical disk, dust, fingerprints, etc. may adhere to the disk surface,
If there are scratches, the light beam will be complicatedly scattered by these deposits, etc., so the measured reflected light intensity will be
The value does not necessarily reflect the state of pit formation.
Therefore, there is a possibility that the recording power cannot be controlled so that an optimum pit is formed.

Further, when dust, fingerprints, etc. adhere to the surface of the disc or are scratched, the intensity of the reflected light is greatly reduced. As one method for solving such a problem, there has been proposed a control method which sets the recording power to a high value so that the reflected light intensity becomes substantially constant (for example, Japanese Patent Laid-Open No. 4-10237). However, in this control method, a recording power exceeding the rating of the laser may be set, so that not only the life of the laser is shortened but also destruction may occur.

Furthermore, depending on the recording medium, the reflected light intensity when the pits are actually formed by the recording laser beam does not necessarily reflect the pit formation state. For example, in the case of "phase change" or "magneto-optical" media,
Since the pit formation state is not always reflected, it may be difficult to control at the optimum recording power level. In general, the term "pit" generally recalls a physical "hole", but in the case of a "phase change" or "magneto-optical" recording medium, it is not a "hole" but a "crystalline state / It means "amorphous state" or "state of magnetization direction". In the following description, these are all referred to as a "mark".

[0005]

A first object of the present invention is to correct the recording power so that a recording mark can be formed well even if dust, scratches, fingerprints, etc. are present on the disk surface. . The second problem is to protect the laser by controlling it so that it does not emit light with excessive power.
The third problem is that even for discs with different recording characteristics,
This is to ensure that the recording mark is formed well.

[0006]

A recording power correction apparatus according to claim 1 is a recording power correction apparatus in an optical disk recording apparatus for forming a recording mark by converging a light beam on a recording surface of an optical disk. In accordance with the series, recording power control means for modulating the intensity of the light beam at the target recording power, a pickup for detecting the reflected light from the recording surface of the light beam to generate a reproduction signal, and a reproduction signal for recording. A level detecting means for detecting the level decrease amount, a power changing means for changing the target recording power according to the level decrease amount, and a memory means for storing a plurality of sets of variable amounts of the target recording power for the level decrease amount in advance, The power varying means refers to the memory means to vary the target recording power.

According to a second aspect of the present invention, there is provided a recording power correction apparatus according to the first aspect, wherein the level detecting means is
The low frequency component of the reproduction signal being recorded is sampled when the low frequency component decreases at a rate of change of a predetermined value or more.

According to a third aspect of the present invention, there is provided a recording power correction apparatus according to the first aspect, wherein the level detecting means is
The amplitude component of the reproduction signal being recorded is sampled when the amplitude component decreases at a rate of change equal to or higher than a predetermined value.

A recording power correction apparatus according to a fourth aspect is the recording power correction apparatus according to any one of the first to third aspects, wherein the memory means preliminarily provides information on the variable amount of the target power with respect to the level reduction amount for each disc type. A plurality of sets are stored, and the power varying means selectively refers to the information regarding the varying amount stored in the memory means for each type of the disc loaded in the optical disc recording apparatus.

The optical disk of claim 5 is an optical disk capable of recording information by converging a light beam, and has a reflectance and recording sensitivity different from those of the data recording area in a test area outside the normal data recording area. A trial writing area is provided.

According to a sixth aspect of the present invention, in the optical disc according to the fifth aspect, the trial writing area has physical characteristics that imitate changes in reflectance and recording sensitivity that are subsequently generated in the optical disc.

According to a seventh aspect of the present invention, there is provided a recording power correction device, wherein a test area outside a normal data recording area is provided with a test writing area having a reflectance and a recording sensitivity different from those of the data recording area. A recording power correction device in an optical disk recording device for condensing a light beam to form a recording mark, and recording power control means for modulating the intensity of the light beam with a target power according to a recording data series, and recording of the light beam. A pickup that detects the reflected light from the surface to generate a reproduction signal, a level detection unit that detects the level reduction amount of the reproduction signal during recording, and a power variable unit that changes the target power according to the level reduction amount. A learning means for performing trial writing in the trial writing area to obtain the relationship between the level reduction amount and the optimum variable amount of the target power for the level reduction amount,
The power varying means is configured to vary the target power in the data recording area by referring to the relationship of the varying amount of the target power with respect to the level reduction amount obtained by the learning means.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a recording power correction device for an optical disk recording apparatus and an optical disk according to the present invention will be described.
Embodiments will be described in detail with reference to the drawings. The recording power correction device of the optical disk recording device will be described in the first to third embodiments, and the optical disk of the fourth embodiment is the recording power correction device using this optical disk. The device will be described in the fifth embodiment.

First Embodiment Although the first embodiment corresponds to the inventions of claims 1 and 2, the invention of claim 1 is a basic invention. In the first embodiment, when the average level of the reproduced signal during recording is lowered, the reduction amount is sampled, and the relationship between the level reduction amount and the recording power increase amount is stored in advance as a table. With reference to, the information about the recording power increase amount is obtained from the sampled level decrease amount, and is added to the target recording power for correction.

FIG. 1 is a functional block diagram showing an example of an embodiment of the main configuration of the optical disk device of the present invention. In the figure, 1 is an optical disc, 2 is a pickup, 3 is a first low-pass filter, 4 is a second low-pass filter, 5 is a dividing circuit, 6 is a differentiating circuit, 7 is a timing generating circuit, and 8 is a threshold value. Circuit, 9 is a sampling circuit, 1
0 is a correction amount table, 11 is an addition circuit, 12 is a recording power control circuit, LB is a light beam, Pw is a target power, and ΔP.
w is the correction amount of the recording power, Pw ′ is the corrected target power, W
write Data is a recording data series, S1 is the output of the first low-pass filter 3, S2 is the output of the second low-pass filter 4, S3 is the output of the division circuit 5, S4 is the output of the differentiation circuit 6, and S5 is sampling. A pulse, S6 is a reset pulse, and S7 is a sampling output.

In the optical disk device of FIG. 1, when the average level of the reproduction signal during recording is lowered, the amount of reduction is sampled. Further, the relationship between the level decrease amount and the recording power increase amount is stored in advance in a memory as a table, and the recording power increase amount is referred to according to the sampled decrease amount, and added to the target recording power for correction. To do.
Here, the pickup 2 will be briefly described.

FIG. 2 is a structural diagram showing a main part of the pickup 2. Reference numerals in the figure are the same as those in FIG. 1, 21 is an objective lens, 22 is a half mirror, 23 is a laser diode (LD), and 24 is a photodetector.

As shown in FIG. 2, the pickup 2
Is a laser diode (LD) 23, an objective lens 21,
It is composed of a half mirror 22, a photodetector 24, and the like. The laser diode 23 includes a recording power control circuit 1 shown in FIG.
The LD drive current Iw output from 2 is given, and light is emitted with a power proportional to this drive current Iw. The light beam LB emitted from the laser diode 23 is the objective lens 2
The light beam is focused at 1 and focused on the recording surface of the optical disc 1. Light beam L reflected on the recording surface of the optical disc 1
B is incident on the photodetector 24 via the half mirror 22, is photoelectrically converted by the photodetector 24, and is reproduced signal RF.
Is generated.

A recording film is formed on the recording surface of the optical disc 1. Recording marks having different reflectances are formed on the recording film by the intensity modulation of the focused light beam LB. For example, in a widely known "phase change" film, recording marks having different reflectances are formed depending on the LD power level, as shown in FIG.

FIG. 3 is a time chart explaining the LD power at the time of forming marks on the "phase change" film. The symbols attached to the waveforms in the figure correspond to the symbol positions in FIG.
w1 and Pw2 are two LD power levels, which are the recording power level and Pr is the reproducing power level.

As shown in FIG. 3, when modulated at the levels of Pw1 and Pw2, a mark having low reflectance is formed on the "phase change" film, and when only the level of Pw2 is given, the reflectance of High marks are formed. Note that at the low reproduction power level Pr, mark formation is not performed, and only the reproduction operation is possible. The recording power control circuit 12 intensity-modulates the laser diode 23 with a power proportional to the corrected target power Pw ′ according to the recording data series Write Data.

The recording power control in this case is performed, for example, by detecting the emission power by the emission power monitor means (not shown) and controlling the LD drive current Iw so that the emission power and the target power Pw match. Done. Further, the emphasis modulation is performed by, for example, Write D in FIG.
As indicated by "ata", when the recording data series is at the "H" level, it is modulated at a high speed between Pw1 and Pw2, and becomes "L".
At the level, it is controlled to emit light at Pw2.

The relation with the corrected target power Pw 'is to make Pw1 and Pw2 proportional to Pw', for example, Pw1 = Pw 'Pw2 = Pw' / K (K is a constant). The enhancement modulation method is not limited to the method described in the first embodiment, and various known methods can be used depending on the characteristics of the recording film, design choices, and the like. Needless to say.

The reproduction signal RF output from the photodetector 24 of the pickup 2 has its high-frequency component cut by the first low-pass filter 3 to obtain an output signal S1 of the first low-pass filter 3. This output signal S1 is further output to the second
Is sent to the low-pass filter 4 of
The output signal S2 of the second low pass filter 4 is generated. In this case, the time constant of the first low-pass filter 3 is longer than the modulation cycle of the recording data series WriteData, and the RF when scanning a place on the optical disc 1 where dust of several tens of μm to several mm is present. Set it short enough to follow signal changes.

The time constant of the second low pass filter 4 is
The time constant is set to be sufficiently longer than the time constant of the first low-pass filter 3 so as not to follow the change of the RF signal due to dust of several mm on the optical disc 1. By setting such a time constant, the output S2 of the second low pass filter 4 becomes R
It is possible to reflect almost the DC level of the F signal. Therefore, the RF signal, the signal S1, and the signal S2 during the recording operation
Microscopically, this state is as shown in FIG.

That is, the RF signal has an L level due to the high frequency attenuation due to the spatial frequency characteristic of the pickup optical system and the frequency characteristic of the photodetector 24 and the preamplifier (not shown).
The D power waveform has a smoothed waveform. Further, although the reflectance of the optical disc 1 is also reflected, whether or not the reflectance change in the process of forming individual recording marks is reflected depends on the characteristics of the recording film.

For example, as described above as a conventional example, a recording film in which the pit formation state is reflected is known (Japanese Patent Laid-Open No. 10237/1992), and there is a recording film which is hardly reflected. . However, in the present invention, such a microscopic change in reflected light is irrelevant and is regarded as an average change in reflected light, so that the desired effect can be obtained regardless of the characteristics of the recording film. The output signal S1 of the first low-pass filter 3 and the output signal S2 of the second low-pass filter 4 have waveforms obtained by further smoothing the RF signal, as shown in FIG.

In FIG. 3, the output signal S1 and the output signal S
2 shows a microscopic view of several marks,
Both have the same waveform (the average level of the RF signal). For example, the “H” level time shown at the beginning of the Write Data in FIG. 3 is on the order of 100 ns. This state is shown in a longer time range as shown in FIG.

FIG. 4 shows RF signals and output signals S1 to S1 of FIG.
It is a time chart which shows the detail about the relation between output signal S6 and LD power. In the figure, point A indicates the zero-cross position of the output signal S4, point B indicates the end point of power correction, and TH1 and TH2 indicate threshold values (slice levels).

The output signal S1 and the output signal S2 shown in FIG. 3 have the waveforms shown in the uppermost stage of FIG.
In this FIG. 4, the output signal S2 is of the order of 100 μs to ms. In FIG. 4, it is assumed that there is dust on the optical disc 1 and the RF signal drops for several 100 μs to several ms when scanning this place. The size of dust is, for example, when the scanning linear velocity is 1 m / s,
If dust with a diameter of 1 mm is present, it is calculated that a decrease in reflected light occurs for about 1 ms.

Then, as shown in the uppermost part of FIG. 4, the signal S1 drops following the decrease in the average level of the RF signal,
The signal S2 does not follow this and almost maintains the level when there is no dust. Here, referring again to FIG. 1, the output signal S1 of the first low-pass filter 3 and the output signal S2 of the second low-pass filter 4 are input to the division circuit 5. The division circuit 5 calculates S1 / S2 of the two input signals to generate an output signal S3.

The output signal S3 of the division circuit 5 indicates the average RF signal level at the dust portion with respect to the average RF signal level when there is almost no dust. Therefore, if this output signal S3 is sampled at an appropriate timing,
The amount of decrease in the average RF signal level due to dust can be obtained. When the output signal S1 is differentiated by the differentiating circuit 6 to obtain this sampling timing, the output signal S4 of the differentiating circuit 6 is obtained.

This output signal S4 is input to the timing generation circuit 7. The timing generation circuit 7 detects the zero cross (point A in FIG. 4) of the input signal S4 and generates the sampling pulse S5. The timing generation circuit 7 can be composed of, for example, a comparator and a logic circuit.

FIG. 5 shows the timing generation circuit 7.
It is a functional block diagram which shows the detailed structural example. In the figure, 31 and 32 are comparators, and 33 is a logic circuit.

The comparators 31 and 32 shown in FIG.
And the threshold value T of the input signal S4
Compare with H2 (<0) and zero (= 0). The comparison result in this case is the logic of S4 <TH2 S4> 0. The comparison result is input to the logic circuit 33. The logic circuit 33 can be configured by, for example, a two-state sequential circuit as shown in FIG.

FIG. 6 is a diagram showing the configuration of the logic circuit 33 which is a two-state sequential circuit. Reference numerals in the drawings are the same as those in FIGS. 1 and 5.

As shown in FIG. 6, state: Wait_TH2 wait until S2 <TH2. Wait for S2 <TH2 to wait_0. Wait for state: Wait_0 S2> TH2. Output S5 pulse when S2> 0. Wait_T
You can set it to H2.

If such a logic circuit 33 is used,
The signal S5 is output at the zero-cross point after the signal S4 becomes equal to or less than the constant value (TH2). This physical meaning is the sampling point of the minimum point (sampling pulse S after the average RF signal S1 is lowered to some extent at a rapid change rate).
It means to get 5). With this function, R
When the change in the F signal level is small, it is possible to perform control so as not to perform power correction, and it is possible to obtain an effect of suppressing undesired power correction operation due to noise or small dust that does not pose a problem.

The sampling circuit 9 samples the signal S3 at the timing of the sampling pulse S5.
As a result, the signal S7 holds the level of the signal S3 at the point A after the point A in FIG. This signal S7 is input to the correction amount table 10. In the correction amount table 10, the relationship of the correction amount ΔPw with respect to the signal S7 level is stored in advance.

The signal S7 takes a value of "1" when the RF signal level is not lowered and takes a value between "0" and "1" when the level is lowered. As an example of the correction amount table 10, when the signal S7 is "1", no correction is necessary, so ΔP
w = 0, and thereafter, as the signal S7 becomes smaller, ΔPw
Set to a large value. In this case, ΔP is set so that the recording laser does not emit light with excessive power and is not destroyed.
It is preferable to limit w to a fixed value.

In the correction amount table 10, dust is attached on the optical disc 1 as a test at the time of designing the device, data is recorded on that portion, and a recording power correction amount that minimizes an error in reproduced data is obtained. Signal S at the dust part
It can be calculated from the value of 7. Since the power correction amount for the signal S7 differs depending on the size of dust and other physical characteristics, the same experiment is performed for many dust patterns, and the relationship between the multipoint signal S7 and the correction amount ΔPw is stored in a table. It is preferable to set.

As described above, it is possible to appropriately correct the recording power for many dust patterns. Such correction can be similarly performed on fingerprints and scratches.
The correction amount ΔPw of the recording power is added to the target power Pw by the adder circuit 11 to obtain the corrected target power Pw ′. Then, when the dust section ends, the RF signal level is restored. When the RF signal level is restored, the level of the signal S3 increases.

This signal S3 is applied to the threshold circuit 8, the level thereof is detected by the threshold circuit 8 to generate a reset pulse S6, and the reset circuit S6 resets the sampling circuit 9 to the level "1". . By resetting the sampling circuit 9, the sampling output S7 becomes S7 = 1, the correction amount ΔPw = 0, and the power correction ends. Further, the threshold circuit 8 is
The signal S3 is compared with a predetermined threshold value TH1, and S3> TH
When it becomes 1, a reset pulse S6 is output.

It is assumed that the sampling circuit 9 is reset to "1" even before entering the dust section. Here, referring to FIG. 4 above, at point A shown in S3 of FIG.
When the signal S3 is sampled, the LD power increases by ΔPw (an amount corresponding to it) according to this level. Then, at the point B shown in S3 of FIG. 4, the power correction is completed,
LD power returns to the original level.

On the other hand, when such a correction is not performed, the signal S between the points A and B shown in S3 of FIG.
The level of 3 is lowered. As described above, in the first embodiment, the target power is variably controlled by referring to the memory means in which a plurality of sets of variable amounts of the target recording power with respect to the reproduction level decrease amount during recording are stored in advance. Therefore, the effective reduction of the recording power due to dust, fingerprints, scratches, etc. attached on the disc is appropriately compensated, and the recording marks are formed well even if they are present. Further, since the correction amount of the recording power can be limited depending on the contents of the memory, it is possible to protect the laser by preventing the recording laser from emitting light with an excessive power.

Second Embodiment This second embodiment corresponds to the invention of claim 3. The second embodiment is different only in that an RF signal amplitude detecting means (41 in FIG. 7 described later) is used instead of the first low-pass filter 3 shown in FIG. The configuration is similar to that of FIG.

FIG. 7 is a functional block diagram showing an example of the embodiment of the RF signal amplitude detecting means used in the optical disk device of the present invention. In the figure, 41
Is an RF signal amplitude detecting means, 42 is a peak holding means for holding the upper peak of the RF signal, 43 is a bottom holding means for bottom holding the lower peak, 44 is a subtracting circuit, and S1 'is the output of the subtracting circuit 44. , PH indicates the output of the peak hold means 42, and BH indicates the output of the bottom hold means.

As shown in FIG. 7, instead of the first low-pass filter 3 shown in FIG. 1, the RF signal amplitude detecting means 41 is used. The RF signal amplitude detection means 41 is
The upper peak of the RF signal is detected by the peak hold means 42, and the lower peak of the RF signal is detected by the bottom hold means 43, and the difference is calculated by the subtraction circuit 44. Then, the calculation result is output as a signal S1 '.

FIG. 8 is a time chart for explaining the operation of the RF signal amplitude detecting means shown in FIG. The symbols attached to the waveforms in the figure correspond to the symbol positions in FIG.

As shown in FIG. 8, the entire operation waveform is substantially the same as that obtained by replacing the signal S1 (amplitude of the RF signal) shown in FIG. 4 with the signal S1 '. In general,
It is assumed that the level decrease due to dust or the like appears more markedly in the amplitude level of the RF signal than in the average light intensity level of the RF signal. Therefore, by using the amplitude detecting means 31 as described above, it is possible to detect the level drop more sensitively, and it is possible to appropriately correct the recording power.

Third Embodiment The third embodiment corresponds to the invention of claim 4, but is also related to the inventions of claims 1 to 3.
In the invention of claim 4, the memory means is used, and a plurality of sets of information regarding the variable amount of the target power with respect to the level reduction amount are stored in advance in this memory means for each type of disk.

FIG. 9 is a diagram conceptually showing an example of the contents of the correction amount table 10 for the memory means used in the recording power correction device of the present invention. In the figure, S7 on the horizontal axis indicates sampling output, and ΔPw on the vertical axis indicates the correction amount.

FIG. 10 is a memory block diagram conceptually showing another example of the contents of the correction amount table 10.

As shown in FIGS. 9 and 10, the memory means stores a plurality of tables such as Table 1, Table 2, .... Each of these tables corresponds to a different type of disc. The optical disc recording device determines the type of disc loaded in the device, selects a table corresponding to each type of disc, and generates a correction amount ΔPw according to the signal S7 level. As described above, the reason why the correction amount table 10 is used for each type of disc is that the appropriate power correction amount is generally different depending on the characteristics of the recording film of the disc even in the same dust mode.

In the recording power correction apparatus of the present invention, as shown in FIGS. 9 and 10, by providing a function of selecting a table corresponding to each type of disc and generating the correction amount ΔPw, only the dust mode can be obtained. Without this, it is possible to perform appropriate power correction even for many disc modes. In this case, the disc type is classified by disc manufacturer, average reflectance, “phase change”, and “Wri”.
It is possible to perform various categorizations such as "te Once" and "magneto-optical" according to recording methods.

As a well-known method, the disc manufacturer may previously write the disc type, maker information, etc. at a predetermined portion of the disc, and the disc recording device may read it. Alternatively, there is also known a method in which the disk recording device measures the average amount of reflected light of the disk before recording and discriminates based on the level of the amount of reflected light. However, since the recording power correction device of the present invention has no feature in the configuration for such determination, detailed description thereof will be omitted.

As described above, according to the third embodiment, in the recording power correction device according to the first to third aspects, the level decrease amount stored in the memory means for each type of loaded disk is compared. The relationship of the variable amount of the target power is selectively referred to. Therefore, an appropriate power correction amount can be obtained even with respect to the difference in the characteristics of the recording film depending on the disc type.

Fourth Embodiment The fourth embodiment corresponds to the inventions of claims 5 and 6. The fourth embodiment is different from the inventions of claims 1 to 4 and relates to an optical disc.

FIG. 11 shows a disc of the present invention.
It is a schematic front view which shows an example of the embodiment. In the figure, 51 is a disk, 52 is a range outside the data area, and G1 to G6 are areas having reflectance and recording sensitivity different from those of the normal area.

The disk 51 has a normal recording film formed in a normal data area (for example, if the outer diameter is 120 mm, the diameter is in the range of 50 mm to 115 mm). Further, in the range 52 outside the area, abnormal areas G1 to G6 having reflectance and recording sensitivity different from those of the normal area are scattered. The areas G1 to G6 have different sizes. Each of these areas G1 to G6 is a data recording area in which an abnormal area that may occur in the future is provided in advance.

The recording device must properly correct the recording power in the abnormal area, but since the disk 51 is provided with the abnormal areas (abnormal areas G1 to G6) in advance, before recording normal data. In addition, it is possible to carry out trial writing in this abnormal area to obtain an appropriate power correction amount. In this case, in the abnormal areas G1 to G6,
It is practical and preferable to have optical characteristics that imitate abnormal areas such as dust, fingerprints, and scratches that will be attached to the disk 51 later. As the simplest method, it is assumed that a shield pattern having a low reflectance is printed on the disk surface. In addition, the number of abnormal regions provided in advance, the size, the variety of other optical characteristics, etc.,
It is not limited to the contents described in this embodiment.

As described above, in the fourth embodiment, the test writing area having the reflectance and the recording sensitivity different from those of the data recording area is provided in the test area outside the normal data recording area of the optical disc. (The optical disc of claim 5). Therefore, the recording device uses this test writing area to provide a test writing area having a reflectance and a recording sensitivity different from those of the data recording area in a test area outside the normal data recording area suitable for the abnormal area. The correction amount can be obtained for each disc.

Further, since the trial writing area has physical characteristics simulating the reflectance and the recording sensitivity change which are subsequently generated on the optical disc, the recording power correction for the abnormal area such as dust and fingerprints or scratches which are subsequently adhered. The amount can be more accurately obtained for each disc (the optical disc of claim 6).

Fifth Embodiment This fifth embodiment corresponds to the invention of claim 7. The fifth embodiment relates to a device using the disk 51 described in the fourth embodiment.

FIG. 12 is a functional block diagram showing an example of another embodiment of the main configuration of the optical disk device of the present invention. The reference numerals in the figure are the same as those in FIG.
Reference numeral 1 is a level measuring circuit, 62 is a data reproducing circuit, 63 is a correction amount table, 64 is a selector, and 65 is a controller.

The disk 51 is the disk shown in FIG. 9, that is, an abnormal area simulating the adhesion of dust is provided in the trial writing area. To simplify the drawing, the first part of FIG.
The low-pass filter 3, the second low-pass filter 4, the division circuit 5, the differentiator 6, the timing generation means 7, the threshold value circuit 8, and the sampling circuit 9 of FIG.
This is indicated by 1. The data reproducing circuit 62 has a function of reproducing recorded data, and reproduces the reproduced data Re.
The ad Data can be read by the controller 65. Further, the level decrease amount S7 of the RF signal can also be read by the controller 65.

The correction amount table 63 is the same as the correction amount table 10 of FIG. 1 in that the recording power correction amount for the signal S7 is stored, but the contents are the same as that of the controller 6.
It can be set from 5. The controller 65 can also independently output the recording power correction amount ΔPw ′, and can switch between the correction amount ΔPw output from the correction amount table 63 and the selector 64.

The optical disc apparatus shown in FIG. 12 is
When a disc is newly loaded (inserted in the device),
Writing is performed in the abnormal areas G1 to G6 of the trial writing area of the disc while changing the recording power correction amount, and this is reproduced to store the recording power correction amount that minimizes the error rate and the signal S7 value at that time. . By such processing, the signal S7 and the optimum recording power correction amount are obtained for each of the abnormal areas G1 to G6, and the contents thereof are set in the correction amount table 63.

Thereafter, the recording power correction amount ΔPw output from the correction amount table 63 is used to automatically perform the power correction when the RF signal level is lowered due to dust or the like during the actual data recording. Next, a process when the controller 65 of FIG. 12 updates the correction amount table 63 by trial writing will be described with a flow. Here, it is assumed that the selector 64 selects the correction amount ΔPw output by the controller 65.

FIG. 13 is a flow chart showing an algorithm example when the controller 65 updates the correction amount table 63 by trial writing. # 1 to # 11 indicate steps.

Steps # 1 to # 10 are a loop for the abnormal area Gi (I = 1, ..., 6).
In steps # 3 to # 8, the recording power correction amount Δ
This is a loop that changes Pw ′ in six ways.

In step # 4, 1 out of the power correction amounts
Choose one. In this case, f1 (j) is an appropriate monotone function and may be stored in a table. For example, a table as shown in FIG. 14 below is created.

FIG. 14 is a diagram showing an example of the f1 (j) table.

In step # 4, the data is written in the abnormal area Gi using the recording power correction amount ΔPw 'determined in step # 3. At this time, since the signal S7 value is measured, the value is stored. In step # 5, the data of the abnormal area Gi written in the previous step # 4 is reproduced. In step # 6, the error rate of the data reproduced in step # 5 is calculated.

In step # 8, the power correction amount that minimizes the error rate is stored as ΔPw (i) from the error rates for the respective power correction amounts obtained in the loop from step # 2 to step # 7. . Further, the signal S7 value at that time is stored as S7 (i). When the loop from step # 1 to step # 9 is exited, for example, as shown in FIG.
A table as shown in Fig. 5 is obtained.

FIG. 15 is a diagram showing an image of the correction amount table 63.

In the correction amount table 63 of FIG. 15, 6
For each of the one abnormal area G1 to G6, one set of signal S7 corresponds to the recording power correction amount ΔPw. When setting such data in the table, interpolation and extrapolation may be appropriately complemented and set.

Further, in order to avoid destruction of the LD due to excessive laser power, it is preferable to limit the recording power correction amount ΔPw value as appropriate. In this way,
Each time a disc is inserted, writing is performed in an abnormal area imitating dust in the trial writing area, and an appropriate recording power correction amount is obtained. With this recording power correction amount, it is possible to compensate for the recording characteristics that differ from disk to disk, the difference in the scattering state of the recording light due to dust, etc., and to perform appropriate power correction.

In the flow of FIG. 13, in step # 10,
The data shown in FIG. 15 is used as the correction amount table 63.
Write to. In step # 11, the selector 64 is switched to the correction amount table 63 side, and the flow of FIG. 13 ends.

As described above, in the fifth embodiment, the test area outside the normal normal data recording area is
An optical disc provided with a test writing area having a reflectance and recording sensitivity different from that of the data recording area is used, and test writing is performed in this test writing area to reduce the reproduction signal level decrease during recording and the target recording power for that. Learning means for determining the relationship of the optimum variable amount is provided, and the power varying means changes the target power by referring to the relationship of the variable amount of the target power with respect to the level reduction amount recognized by the learning means in the data recording area. ing. Therefore, it is possible to obtain an appropriate recording power correction amount by performing writing in an abnormal area imitating dust in the trial writing area each time the disc is inserted. Since different recording characteristics and differences in the recording light scattering state due to dust and the like are compensated for, appropriate power correction is possible.

[0081]

According to the recording power correction apparatus of the optical disk recording apparatus of the first aspect, the target power can be varied by referring to the memory means in which a plurality of variable amounts of the target recording power with respect to the reduction amount of the reproduction level during recording are stored in advance. Have control. Therefore, effective reduction of the recording power due to dust, fingerprints, scratches, etc. adhering to the disc is properly compensated, and even if there is any, the recording mark is formed well.
Also, the correction amount of the recording power can be limited by the contents of the memory so that the recording laser does not emit light with excessive power,
The laser can be protected.

According to a second aspect of the present invention, there is provided a recording power correction apparatus according to the first aspect, wherein the reproduction level is lowered during recording when the low frequency component of the reproduction signal during recording is reduced at a predetermined rate or more. Is detected by sampling the low frequency component of. Therefore, an appropriate recording power correction can be performed with a simple configuration.

According to a third aspect of the present invention, there is provided a recording power correction apparatus according to the first aspect, in which the reproduction level is reduced during recording when the amplitude component of the reproduction signal during recording is reduced at a rate of change of a predetermined value or more. , Amplitude component is detected by sampling. Therefore, it is possible to detect the level drop more accurately and perform appropriate recording power correction.

According to a fourth aspect of the present invention, in the recording power compensation apparatus according to the first to third aspects, the target power is varied with respect to the level reduction amount stored in the memory means for each type of loaded disc. We decided to selectively refer to the quantity relationship. Therefore, an appropriate power correction amount can be obtained even with respect to the difference in the characteristics of the recording film depending on the disc type.

According to the fifth aspect of the invention, a test writing area having a reflectance and a recording sensitivity different from those of the data recording area is provided in a test area outside the normal data recording area of the optical disk. Therefore, the recording device uses this test writing area to provide a test writing area having a reflectance and a recording sensitivity different from those of the data recording area in a test area other than the normal data recording area for the abnormal area. The quantity can be obtained for each disc.

In the optical disc of claim 6, the test writing area has physical characteristics simulating the reflectance and the recording sensitivity change that occur later on the optical disc, so that the dust / fingerprints or the abnormalities such as scratches that are attached later are abnormal. The recording power correction amount for the area can be obtained more accurately for each disc.

According to a seventh aspect of the present invention, there is provided a recording power correction apparatus which uses an optical disc having a test writing area having a reflectance and a recording sensitivity different from those of the data recording area in a test area outside a normal data recording area. There is provided learning means for performing trial writing in this trial writing area to obtain the relationship between the reproduction signal level reduction amount during recording and the optimum variable amount of the target recording power for the reduction, and the power varying means is provided in the data recording area. The target power is made variable by referring to the relationship of the amount of change in the target power with respect to the level reduction amount recognized by. Therefore, each time a disc is inserted,
By writing in an abnormal area simulating dust in the trial writing area, it is possible to obtain an appropriate recording power correction amount. Depending on the obtained recording power correction amount, different recording characteristics for each disc and recording due to dust etc. Since the difference in the light scattering state and the like are compensated, appropriate power correction becomes possible.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing an example of an embodiment of a main part configuration of an optical disk device of the present invention.

FIG. 2 is a structural diagram showing a main part of a pickup 2.

FIG. 3 is a time chart explaining LD power at the time of forming marks on a “phase change” film.

4 is the RF signal of FIG. 1, output signal S1 to output signal S
6 is a time chart showing the details of the relationship between LD power.

5 is a functional block diagram showing a detailed configuration example of the timing generation circuit 7. FIG.

FIG. 6 is a diagram showing a configuration of a logic circuit 33 including a 2-state sequential circuit.

FIG. 7 is a functional block diagram showing an example of an embodiment of RF signal amplitude detection means used in the optical disk device of the present invention.

FIG. 8 is a time chart for explaining the operation of the RF signal amplitude detection means shown in FIG.

FIG. 9 is a diagram conceptually showing an example of the contents of a correction amount table 10 for the memory means used in the recording power correction device of the present invention.

FIG. 10 is a memory configuration diagram conceptually showing another example of the contents of the correction amount table 10.

FIG. 11 is a schematic front view showing an example of an embodiment of the disc of the present invention.

FIG. 12 is a functional block diagram showing an example of another embodiment of the main configuration of the optical disc device of the present invention.

FIG. 13 is a flowchart showing an algorithm example when the controller 65 updates the correction amount table 63 by trial writing.

FIG. 14 is a diagram showing an example of a table of f1 (j).

FIG. 15 is a diagram showing an image of a correction amount table 63.

[Explanation of symbols]

 1 Optical Disc 2 Pickup 3 First Low-pass Filter 4 Second Low-pass Filter 5 Division Circuit 6 Differentiation Circuit 7 Timing Generation Circuit 8 Threshold Circuit 9 Sampling Circuit 10 Correction Amount Table 11 Addition Circuit 12 Recording Power Control Circuit

Claims (7)

[Claims] 1. A recording power correction apparatus in an optical disk recording apparatus for forming a recording mark by converging a light beam on a recording surface of an optical disk, wherein the intensity of the light beam is set to a target recording power in accordance with a recording data series. A recording power control unit that modulates with, a pickup that generates a reproduction signal by detecting reflected light from the recording surface of the light beam, and a level detection unit that detects a level reduction amount of the reproduction signal during recording, The power varying means for varying the target recording power according to the level reduction amount; and the memory means for storing a plurality of sets of variable amounts of the target recording power for the level reduction amount in advance. A recording power correction apparatus, wherein the target recording power is varied with reference to the means. 2. The recording power correction device according to claim 1, wherein the level detection means samples the low frequency component when the low frequency component of the reproduction signal being recorded is reduced at a change rate of a predetermined value or more. A recording power correction device characterized by the above. 3. The recording power correction apparatus according to claim 1, wherein the level detecting means samples the amplitude component of the reproduction signal being recorded when the amplitude component decreases at a rate of change of a predetermined value or more. Characteristic recording power correction device. 4. The recording power correction device according to claim 1, wherein the memory means stores in advance a plurality of sets of information regarding the variable amount of the target power with respect to the level reduction amount for each type of disc. The recording power correction device, wherein the power varying means selectively refers to information on the varying amount stored in the memory means for each type of disc loaded in the optical disc recording device. 5. An optical disk capable of recording information by converging a light beam, wherein a test writing area having a reflectance and a recording sensitivity different from those of the data recording area is provided in a test area outside a normal data recording area. An optical disc characterized by being provided with. 6. The optical disc according to claim 5, wherein the trial writing area has physical characteristics simulating a reflectance and a recording sensitivity change which are subsequently generated in the optical disc. 7. A light beam is focused on a recording surface of an optical disc having a test writing area having a reflectance and a recording sensitivity different from those of the data recording area in a test area outside the normal data recording area. A recording power correction device in an optical disk recording device for forming a recording mark, comprising: recording power control means for modulating the intensity of the light beam with a target power in accordance with a recording data series; and reflected light from the recording surface of the light beam. A pickup for generating a reproduction signal, a level detecting means for detecting a level reduction amount of the reproduction signal being recorded, a power varying means for varying the target power according to the level reduction amount, A test means is provided for performing trial writing in a trial writing area to obtain a relationship between the level decrease amount and an optimum variable amount of a target power for the level decrease amount. The recording power correction device, wherein the changing means changes the target power in the data recording area with reference to the relationship between the level decrease amount obtained by the learning means and the variable amount of the target power.