JP3413013B2 - Information recording device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording device such as an optical disk device, and more particularly to a recording power correction device and a rotation control device for the information recording device.

[0002]

2. Description of the Related Art In an information recording apparatus such as an optical disk apparatus that forms an information recording mark by irradiating a disk with a light beam, it is necessary to accurately control the recording power emitted from a laser. The first method for correcting the recording power is
In the prior art, the test power is changed by changing the recording power of the laser in several steps, the area in which the test write is performed is reproduced, and the area in which the index showing the quality of the reproduction signal shows the best value is tested. An optical disk device in which the writing power is set to the optimum recording power has already been proposed (for example, JP-A-5-109077). In this optical disk device, the second harmonic component is used as an index indicating the quality of the reproduction signal, and the power when this is the minimum is the optimum power. According to this optical disk device, it is possible to set the optimum recording power according to the difference in recording sensitivity between disks and the difference in sensitivity due to ambient temperature.

As a second conventional technique, recording power is controlled by controlling the recording power based on the intensity of the returning laser beam (reflected light) when pits are formed during the actual recording operation by the recording laser beam. A control method of a recording laser beam has been already proposed in which optimum pits are always formed even if the optimum recording power changes due to variations in the sensitivity of the medium, tilts, etc. (for example, Japanese Patent Laid-Open No. 4-10).
237). According to this recording laser beam control method, it is possible to compensate for a difference in recording sensitivity in the disc, a laser wavelength variation that occurs during an actual information recording operation, and a variation in recording efficiency due to a beam positioning error.

[0004]

According to the above-mentioned first prior art, the recording power is set by changing the recording power of the laser in several steps and executing the trial writing. It is possible to set the optimum recording power according to the difference in sensitivity and the difference in sensitivity due to the ambient temperature. However, there remains a problem that it is not possible to compensate for a difference in recording sensitivity within the disc, a laser wavelength variation that occurs during an actual information recording operation, and a variation in recording efficiency due to a beam positioning error.

When the recording power that minimizes the second harmonic in the trial writing reaches the upper limit of the changed recording power range, the actual optimum power is probably higher than the detected power. Imagine being there. Therefore, if recording is performed in the upper limit state of the detected recording power range, a recording mark with insufficient power is generated and a reproduction error increases. Even with this method, it is possible to obtain the optimum power by extrapolation, but in that case,
There may be levels where its power exceeds the rating of the laser, which can cause laser breakdown.

On the other hand, in the second prior art, since the power of the state where the pits are formed during the actual recording operation is detected by the recording laser beam, the difference in the recording sensitivity in the disk and the actual information are recorded. It is possible to compensate for variations in recording efficiency due to variations in laser wavelength and beam positioning errors that occur during recording operations. However,
Also in the second conventional technique, the recording power requirement may exceed the laser rating as in the first conventional technique. Therefore,
In general, for example, CD-R (CD Recordable
e) In an optical disk device such as a device, a method of determining the optimum power by trial writing as in the first conventional technique and a method of correcting the power during the recording operation as in the second conventional technique are combined. I am trying to use it. Further, in order to avoid such a problem, if the recording power is restricted so that it can be set within the laser rating, the original power requirement cannot be met, and good recording marks cannot be formed. is there.

Further, in both the first and second conventional techniques, the rotational speed of the disk during recording, that is, the linear velocity remains at a predetermined value and does not change. However, if the optimum power determined by trial writing is lower than the rated upper limit, the linear velocity can be further increased and the recording time can be shortened in principle if the device is used at the full rated power. To summarize the above, an apparatus having a function of determining the optimum power by trial writing described in the first conventional technique and a second device
The device equipped with the function to correct the power during recording described in the above-mentioned prior art, or the device equipped with a combination of both functions, does not make full use of the original laser performance and is used in a state where the efficiency is reduced. You are doing it.

An object of the present invention is to solve the problems in the first and second prior arts. Specifically, firstly, due to the difference in recording sensitivity of the disc and the difference in ambient temperature. That is, even if the optimum recording power is different, a good recording mark can be formed . A second problem is to prevent laser breakage even if the optimum recording power exceeds the laser rating due to the difference in recording sensitivity between disks and the difference in ambient temperature . A third problem is to perform high-speed recording when the recording power has a margin due to the difference in recording sensitivity of the disc and the difference in ambient temperature .

The fourth problem is that even if the recording efficiency fluctuates due to the difference in the recording sensitivity in the disc, the laser wavelength fluctuation, the beam positioning error, etc. during the actual recording of information, it is always good. That is, it is possible to form various recording marks . The fifth problem is that while the information is actually being recorded, even if the recording efficiency fluctuates due to the difference in the recording sensitivity in the disc, the laser wavelength fluctuation, the beam positioning error, etc., the recording power request is required. It is to prevent laser damage by not exceeding the laser rating .
A sixth problem is to perform high-speed recording when the recording power has a margin during the actual recording of information .

[0010]

[0011]

[0012]

According to a first aspect of the invention, in an information recording apparatus for forming an information recording mark by irradiating a disk with a light beam, a recording power level indicating a state of formation of the information recording mark during a recording operation. A reproduction means for obtaining a reproduction signal at the time of light emission, a comparison means for comparing the level of the reproduction signal with a predetermined value, and a control means for varying the power of the light beam and the rotation speed of the disk according to the comparison result are provided. ing.

According to a second aspect of the invention, a light beam is applied to the disk.
To an information recording device that irradiates the light to form an information recording mark.
The information recording mark formation status during the recording operation.
Reproduction means for obtaining a reproduction signal, and the level and position of the reproduction signal
Comparing means for comparing the value, when the light beam power during a recording operation controlled by the comparison result is within a predetermined range, by varying the power of the light beam by the comparison result, and out of the predetermined range Tokoro the light beam power is when it comes
There is provided control means for varying the rotation speed of the disk according to the comparison result in a state where the value is constant within a fixed range .

[0014]

[0015]

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the information recording apparatus of the present invention will be described in detail with reference to the drawings.

First Embodiment The first embodiment is characterized in that the recording power is varied to perform trial writing, and the rotation speed at the time of information recording is determined based on the result. In this way, the recording power is made variable and trial writing is performed to determine the rotation speed.
The reason is that, as described above, a good recording mark can be formed even if the optimum recording power is different due to the difference in recording sensitivity of the disc and the difference in ambient temperature. The second reason is to prevent laser breakage even if the optimum recording power exceeds the laser rating due to a difference in recording sensitivity between disks and a difference in ambient temperature. The third reason is to perform high-speed recording when the recording power has a margin due to the difference in recording sensitivity of the disc and the difference in ambient temperature. First, the information recording apparatus of the present invention will be described.

FIG. 1 is a functional block diagram showing an example of an embodiment of the main configuration of the information recording apparatus of the present invention. In the figure, 1 is a disk, 2 is a rotation motor, 3 is an optical head, 4 is a reproduction signal detecting means, 5 is an upper and lower amplitude detecting means, 6 is a laser power control means, 7 is a rotation control means, and 8 is a controller, WData indicates write data.

In the information recording apparatus shown in FIG. 1, a vertical amplitude detecting means 5 is added, and a controller 8 is provided.
The basic configuration is the same as that of the conventional device except that the control is performed according to the flow of FIG. Also in the second embodiment, the hardware configuration is the same, and the controller 8 controls according to the flow of FIG. 4 described later. The configuration and operation of each part will be briefly described. The disk 1 is rotationally driven by the rotary motor 2. The optical head 3 is composed of a laser light source, an optical system, and the like, which are not shown, and can access any information track of the disc 1. A recording mark is formed on the recording surface of the disc 1 by the heat of the laser beam emitted from the optical head 3.

The reflected light of the laser beam is also detected by the optical head 3, and the reproduction signal detecting means 4 converts the reflected light from the recording mark into an electric signal. Normally, a strong power laser beam is emitted during recording to form a recording mark, and reading is performed with a weaker power during reproduction. From the output of the reproduction signal detecting means 4,
The upper and lower envelope levels of the reproduced signal are detected by the upper and lower amplitude detecting means 5. The upper and lower envelope levels can be read by the controller 8.

The controller 8 is composed of a known microprocessor, A / D converter, D / A converter and the like. Further, the controller 8 is the laser power control means 6
A recording power command is output to. The laser power control means 6 causes the laser of the optical head 3 to emit light at the recording power in synchronization with the recording data (write data WData) based on this recording power command value. More specifically, the laser power control means 6 comprises a power detection means for detecting the laser emission power and a comparison means for comparing the recording power command value with the detected emission power, and the recording laser based on the comparison result. Is configured to drive. Therefore, the recording laser can emit light with a power proportional to the recording power command value.

The controller 8 not only outputs a recording power command value to the laser power control means 6, but also outputs a rotation command to the rotation control means 7. The rotation control means 7 rotates the rotation motor 2 based on the rotation command value. More specifically, the rotation control means 7 is
It is provided with a detecting means for detecting the rotational speed or linear velocity of the disk 1 and a comparing means for comparing the rotational command value with the detected rotational speed or linear velocity, and drives the rotary motor 2 based on the comparison result. Has been done. Therefore, the rotary motor 2 can rotate at an angular velocity or a linear velocity proportional to the rotation command value.

FIG. 2 is a flow chart showing a main processing flow for determining the number of revolutions at the time of recording information by varying the recording power in the information recording apparatus shown in FIG. In the figure, # 1 to # 6 indicate steps.

In the flow of FIG. 2, steps # 1 to # 3
The processing itself is known, and is characterized by the processing of steps # 4 to # 6. In step # 1, the recording power Pw is set to the lower limit L.
By varying from lim to the upper limit Ulim, test recording patterns are sequentially recorded in a predetermined trial writing area of the disk 1. At this time, the controller 8 outputs a recording power command to the laser power control means 6 in order to change the recording power Pw. As the recording pattern, for example, random recording data digitally modulated based on a predetermined recording modulation method is used. Further, the variable amount (step) of the recording power Pw is indicated by Pd.

Here, the power lower limit Llim and the power upper limit U
As an example of specific values of lim and the variable amount (step) Pd, Llim = 6 mw, Ulim = 10 mw, Pd =
It can be set as 0.5 mw. Then, in this case, it is possible to sequentially record with 9 kinds of recording powers Pw. It is preferable that the upper limit of power Ulim is set near the rated value of the laser because it can deal with a wide range of discs having different sensitivities within a range that does not damage the laser.

In step # 2, the previously recorded trial writing area is sequentially reproduced to detect an index (called β) of reproduced signal quality. Since this reproduction signal quality index β is obtained for each recording power Pw, a table of Pw vs β can be obtained. Although this index β will be described in detail later, this index β is a negative value when the recording power Pw is insufficient, a positive value when it is excessive, and monotonically increases with respect to the recording power Pw. It is an index. In the next step # 3,
The optimum recording power Pwo is obtained from the obtained Pw vs. β table. For example, Pw where β = 0 is the optimum power.
This optimum recording power Pwo can be obtained by obtaining an appropriate approximate straight line or curve from the above Pw vs. β table data.
It can be calculated easily.

As described above, this first embodiment is characterized by the processing of steps # 4 to # 6 below.
The controller 8 manages the control. In step # 4, it is determined whether the previously obtained optimum recording power Pwo does not exceed the power upper limit Ulim. Optimal recording power Pwo
Is above the power upper limit Ulim, the process proceeds to step # 5, the recording power Pw is set to the upper limit Ulim, and the disc rotation speed is corrected.

For example, if the normal rotational speed (or linear velocity) of the disk is fo, then the rotational speed fo'of the disk is

[Equation 1] fo '= fo * (Ulim / Pwo) ² ... Correction is made as in the equation (1) of (1). Therefore, the rotation speed in this case is reduced in proportion to the square of the shortage of the recording power. In this state, the recording power Pw should be the power upper limit Ulim (Pw = Ulim).

Generally, the required recording energy of a recordable rotary optical disk is almost proportional to the square root of the linear velocity. Therefore, if the number of rotations is lowered according to the above equation (1), good recording becomes possible. , Favorable results are obtained. If the optimum recording power Pwo does not exceed the power upper limit Ulim (less than or equal to the power upper limit Ulim value) as a result of the determination in step # 4, the process proceeds to step # 6.
The optimum recording power Pwo is directly used as the recording power Pw,
The rotation speed is also kept at the normal rotation speed (or linear velocity) fo of the disk.

In the above embodiments, the number of revolutions of the disk has been mainly described. However, in the case of a recording system with a constant linear velocity, "linear velocity" may be adopted instead of "revolution number". . The information recording apparatus of the present invention can be applied to any system of constant rotation speed (angular velocity) or constant linear velocity. In the following description, the same applies to all cases, and the description will be made centering on the “rotation speed”, but it is also possible to apply to the “linear velocity”, and it goes without saying that both are included. By the processes of the above steps # 1 to # 6, particularly the latter half steps # 4 to # 6, the laser power is controlled so as not to exceed the power upper limit Ulim value, and as a result, laser breakage is also prevented. In addition, the optimum recording state, on the other hand, by selecting the recording power Pw,
On the other hand, they are each realized by selecting the number of revolutions. Next, the reproduction signal quality index β described above will be described in detail.

FIG. 3 explains the β value as one of the indexes of the reproduced signal quality. (1) is a case where the recording power is insufficient, (2) is a proper case, and (3) is an excessive case. FIG. The horizontal axis of the figure is time t, and the vertical axis is a high frequency signal (reproduction signal).
HF Signal, A1 indicates the level of the upper envelope, and A2 indicates the level of the lower envelope.

The reproduced signal is detected by a signal called a high frequency signal HF Signal, as shown on the vertical axis of FIG. There are generally a plurality of types of recording marks, from short marks to long marks. In FIG. 3, a waveform when the high-frequency signal HF Signal is AC-coupled (a signal in which a DC component is cut off) and reproduced is schematically shown.

For example, as shown in FIG. 3 (1), when the recording power is insufficient, the level A1 of the upper envelope and the level A2 of the lower envelope are shifted to the lower side, and vice versa. Three
As in (3), when the recording power is excessive, the level A1 of the upper envelope and the level A2 of the lower envelope are shifted upward. Here, the β value is an amount obtained by normalizing the shift amount with the amplitude, and

## EQU00002 ## .beta. = (A1 + A2) / (A1-A2) ... Defined as in the equation (2) of (2). Therefore, if appropriate,
It becomes approximately β = 0. Instead of such a value of the index β, it is also possible to use an index of the reproduced signal second harmonic component as described in the prior art (Japanese Patent Laid-Open No. 5-109077). In short, it is sufficient to use a method in which the optimum recording power Pwo can be obtained from the reproduction signal of the trial writing area recorded while changing (pretending) the power.

Second Embodiment In this second embodiment as well, the hardware configuration is the same as in FIG. 1 described above, and the control (algorithm) by the controller 8 is the same as in the first embodiment described above. Is only different. Next, the operation of the second embodiment is shown in the flow chart.

FIG. 4 is a flow chart showing the main processing flow in the information recording apparatus shown in FIG. 1 when the recording power is changed and the number of rotations is determined during information recording according to the second embodiment. In the figure, # 11 to # 16 indicate steps.

The processing from step # 11 to step # 14 is the same as step # 1 to step # 4 in FIG. That is, the optimum recording power Pwo is obtained by the processing from step # 11 to step # 13.
Then, in step # 14, it is determined whether the obtained optimum recording power Pwo does not exceed the power upper limit Ulim.

In the second embodiment, if the optimum recording power Pwo exceeds the power upper limit Ulim as a result of the determination in step # 14, the process proceeds to step # 15, and the linear velocity (or the rotation speed) is changed. Decrease by a certain value.
After that, the process returns to the previous step # 11, and the same processing is repeated until the optimum recording power Pwo does not exceed the power upper limit Ulim (trial writing repetition procedure).
Dan) . By such processing, the optimum recording power Pw
When the value o does not exceed the power upper limit Ulim, the process exits this loop and the recording power Pwo is set in step # 16.
Set to. Other processes are the same as those in FIG.
Therefore, within a range in which the optimum recording power does not exceed the upper limit Ulim, the required number of rotations is reduced and a good recording state can be obtained. Since the value obtained directly from the Pw vs. β table is adopted as the optimum power in the effect of the second embodiment, the optimum optimum recording state is more accurate than the algorithm for performing the processing of FIG. The point is that you can get it. Also,
In the processing described with reference to FIG. 2 and FIG. 4 above, when the recording power is insufficient, the power is limited to almost the upper limit, so that laser destruction is not caused and the laser power is utilized to the maximum extent. In addition, it is possible to obtain an effect that the recording speed is not unnecessarily slowed down . Here, the relationship between the reproduction signal quality index β and the recording power Pw described with reference to FIG. 3 will be described.

FIG. 5 is a characteristic diagram showing the relation between the recording power Pw and the index β. (1) is a diagram for explaining that there are a plurality of relations of Pw and β, and (2) is the case where the linear velocity is small. It is a figure explaining that the characteristic of Pw vs. β shifts to the upper direction. The horizontal axis of the figure shows the recording power Pw, and the vertical axis shows the index β.

FIG. 5 (1) shows that there are a plurality of Pw to β relationships due to the difference in recording sensitivity of the disc, the ambient temperature, and the like. In FIG. 5 (1), three characteristic curves are shown, but which characteristic is determined by the difference in recording sensitivity of the disc, the ambient temperature, and the like.
Further, FIG. 5 (2) shows that when the linear velocity is changed, when the linear velocity is decreased, the characteristic curve of Pw vs. β is shifted upward.

For example, when the optimum recording power Pwo is calculated for the bottom plot having the highest linear velocity, the power upper limit Ulim is exceeded. Therefore, if the recording power Pw is set in this state, there is a risk of laser breakage. Therefore, when the linear velocity is slowed down, the plot is shifted upward, for example, like the characteristic curve shown in the center, and the optimum recording power Pwo comes below the power upper limit Ulim. The control (algorithm) by the controller 8 shown in FIG. 2 and FIG.
The characteristics shown in are used.

Third Embodiment In the first and second embodiments, the case has been described in which the recording power is changed to perform the trial writing, and the rotation speed at the time of information recording is determined based on the result. The third embodiment is characterized in that the recording power is kept constant, the rotational speed of the disk is varied to perform trial writing, and the rotational speed at the time of information recording is determined based on the result. in this way,
The reason why the rotation speed of the disc is changed and trial writing is performed, and the rotation speed at the time of recording information is determined based on the result is the same as in the first and second embodiments.

That is, the first reason is that, as described above, a good recording mark can be formed even if the optimum recording power is different due to the difference in recording sensitivity of the disc and the difference in ambient temperature. This is because. The second reason is to prevent laser breakage even if the optimum recording power exceeds the laser rating due to a difference in recording sensitivity between disks and a difference in ambient temperature. The third reason is that due to the difference in recording sensitivity of the disc and the difference in ambient temperature,
This is to perform high-speed recording when there is enough recording power. Also in the third embodiment, the hardware configuration is
Similar to FIG. 1 above, but in this case the recording power P
Let w be a predetermined value. For example, it is set near the power upper limit Ulim as described above.

FIG. 6 is a flow chart showing the main processing flow in the information recording apparatus shown in FIG. 1 for varying the rotation speed of the disk according to the third embodiment to determine the rotation speed at the time of information recording. is there. In the figure, # 21 to # 2
3 shows a step.

In step # 21, the linear velocity (or rotational speed) is varied from the lower limit Llim to the upper limit Ulim,
Test recording patterns are sequentially recorded in a predetermined trial writing area of the disk 1. In step # 22, the trial recording areas previously recorded are sequentially reproduced to obtain a table of "linear velocity" vs. "reproduction signal quality index (β)". In the next step # 23,
The optimum linear velocity Vo is calculated from the obtained table of "linear velocity" vs. "reproduction signal quality index (β)" (optimum recording linear velocity
Determining method) . As a method of calculating this optimum Vo, an appropriate approximation method as described in the control (algorithm) of FIG. 2 can be used.

The value of Vo thus obtained is used as a linear velocity to issue a rotation command, and actual data recording is performed. By such control, recording can be performed at the optimum linear velocity near the power upper limit Ulim. In this case, when the normal linear velocity (or the number of rotations) is set, if the recording power Pw has a margin, it should be possible to perform recording at a higher linear velocity as the performance. This third
In the embodiment, since the linear velocity as high as possible is set in the vicinity of the upper limit Ulim of the recording power, high speed recording can be performed.

In the flow of FIG. 6 described above, since the variable control of the recording power is not performed, the device configuration is simpler than that of the device of FIG. 1, and the cost is reduced accordingly. Further, it is possible to easily change the flow shown in FIG. 2 to “if the recording power Pw has a margin, increase the number of rotations”. For example, step # 4 (processing to determine whether the previously obtained optimum recording power Pwo does not exceed the power upper limit Ulim) and step # 6
(The process of keeping the optimum recording power Pwo as the recording power Pw as it is and the rotation speed as the normal rotation speed fo of the disk) is deleted, and after the processing of step # 3, the process moves to step # 5. do it.

The process of step # 5 is a process of setting the recording power Pw to its upper limit value Ulim and correcting the disc rotation speed. Whenever you have enough power,
Since the recording power Pwo <power upper limit Ulim, (Uli
m / Pwo)> 1 and the rotational speed is increased. By the way, if the linear velocity is increased, the value of the index β decreases. This relationship is shown in FIG. 7 below.

FIG. 7 is a characteristic diagram showing the relationship between the linear velocity and the index β. The horizontal axis of the figure shows the linear velocity, and the vertical axis shows the index β.

As shown in FIG. 7, the reproduction signal quality index β has a characteristic that it decreases on the contrary when the linear velocity increases. The characteristic shown in FIG. 7 is an example of “linear velocity” versus “β value” used in the control (algorithm) shown in FIG. As described above many times, the embodiment of the present invention mainly describes the case of using the reproduction signal quality index β, but the present invention is not limited to such a β value, and another It is possible to use an indication of the quality of the reproduced signal.

However, since this β value can be measured by a simple envelope detection circuit and a microcomputer, the device is much simpler than the method of measuring the second harmonic or the reproduction error rate and using it as an index. It is possible to configure. Therefore, it goes without saying that utilizing this β value is a very preferable method in practice.

Fourth Embodiment This fourth embodiment corresponds to the inventions of claims 1 and 2 . In the above-described first to third embodiments, the case has been described in which the recording power is changed or the rotation speed of the disk is changed to perform trial writing, and the rotation speed at the time of information recording is determined based on the result. The fourth embodiment is characterized in that, during the recording operation, one or both of the recording power and the rotational speed of the disk are changed according to the result of comparison between the level of the reproduction signal from the recording mark and a predetermined value. is doing.

Therefore, during the actual recording of information, the difference in the recording sensitivity in the disc, the fluctuation of the laser wavelength,
Even if the recording efficiency fluctuates due to a beam positioning error or the like, an effect that a good recording mark can be always formed can be obtained. Specifically, the B level indicating the mark formation state is set as a reference, the recording actually performed is reproduced, and the reproduction signal level is sampled and compared with this B level.

FIG. 8 is a functional block diagram showing an example of the main configuration of the fourth embodiment of the information recording apparatus of the present invention. The reference numerals in the figure are the same as those in FIG.
Is a B level detecting means, 12 is a comparator, 13 is a first integrator, 14 is a second integrator, and 15 is a controller.
Pw is a target power command and V is a rotation command value.

The information recording apparatus shown in FIG. 8 is the same as that shown in FIG.
Blocks 11 to 14 are provided instead of the upper and lower amplitude detection means 5. The controller 15
The basic control operation is almost the same as that of the controller 8 of FIG. 1, but the control is different, and therefore different reference numerals are given. The B level detecting means 11 samples the reproduction signal level when the laser is emitting light at the recording power level, and outputs a signal called B level. As described above, this B-level signal is a signal indicating the mark formation state. For example, when the mark formation is insufficient, the B level becomes a high level, and conversely, when the mark formation is excessive, B
The level will be low.

The optimum recording state is when the B level is a predetermined value. The predetermined B level is set as a target level, and the actual B level is compared by the comparator 12. The comparison result is sent to the first integrator 13 and the second integrator 14. First, one of the first integrators 13 is
The detected B level is integrated and the target power command Pw is output. In this state, when the detected B level becomes lower than the target B level, the target power command Pw is decreased to control so that the mark formation does not become excessive.

Therefore, the detected B level is raised and coincides with the target B level. The other second integrator 14 integrates the target B level and outputs the rotation command value V. Then, when the detected B level becomes lower than the target B level, the rotation command value V increases, the rotation of the disk becomes faster, and control is performed so that mark formation is not excessive. Therefore, the detected B level is increased and coincides with the target B level.

The first integrator 13 and the second integrator 14 stop the integration in response to a holding command from the controller 15, and hold the immediately preceding integrated value. When the hold command is released, integration is performed. Controller 15
Inputs the output (Pw) of the first integrator 13 and the output (V) of the second integrator 14, and outputs the first and second
The respective holding commands are output to the integrators 13 and 14. In this state, one of the first and second integrators 13 and 14 is operated according to the current recording power (Pw) and the rotation speed (V), and the other is held. That is, the current recording power (Pw) and the number of revolutions (V) are monitored, and when they differ from the power target value, the recording power (Pw) and the number of revolutions (Pw) are detected by comparing the detected B level and the target B level. V) is variably controlled.

More specifically, the recording power (Pw)
Is about to exceed the upper limit Ulim, the first integrator 13 is held so that the power does not rise further, and the second integrator 14 is turned on to start integration.
As a result, the number of rotations is reduced, and the recording state becomes appropriate. After that, when the recording state becomes excessive, the rotation speed starts to increase, and when a certain rotation speed (for example, the first normal rotation speed) is reached, the second integrator 14 is brought into the holding state and the first The integrator 13 is turned on to start integration.
This relationship is shown in the state transition diagram of FIG.

FIG. 9 is a state transition diagram of the controller 15 according to the fourth embodiment. In the figure, S1 and S2
Is the state, int1 is the first integrator 13, and int2 is the second
Ulim is an upper limit value of the power Pw, Vlim
n indicates a normal rotation speed (nominal).

As shown in FIG. 9, the controller 15 of FIG. 8 has a sequential circuit configuration having two states S1 and S2. First, in the state S1, int1 (first integrator 13) is turned on and int2 (second integrator 14) is held. When the relationship between the target power command Pw and the power upper limit Ulim is Pw <Ulim, the state S1
If Pw ≧ Ulim, the state S2 is set.
In the state S2, conversely, int1 (first integrator 13) is held and int2 (second integrator 14) is turned on.

In this state S2, the relationship between the rotation command value V and the actual rotation speed (detected rotation speed) is maintained while V <Vn (first normal rotation speed), and the relationship between the two is V ≧ V
When it becomes n, the state S1 is set. By the controller 15 performing such an operation, the power Pw becomes the upper limit U.
Until reaching lim, the power Pw is controlled by the comparison result between the target B level and the detected B level, and when the power Pw reaches the upper limit Ulim, the rotation speed V is determined by the comparison result between the target B level and the detected B level. Can be controlled. When the relationship between the recording power Pw and the rotation speed V in this case is shown in a waveform diagram, it changes as shown in FIG.

FIG. 10 is a waveform diagram showing the relationship between the recording power Pw and the rotation speed V based on the state transition of the controller 15 in the fourth embodiment. The horizontal axis of the figure is time t,
The waveform Pw indicates the recording power Pw, V indicates the rotation speed V, and S1
And S2 are states, Ulim is an upper limit value of power, and Vn is a normal rotation speed.

As is apparent from FIG. 10, initially, the rotation speed V is constant and the recording power Pw is sequentially increased. When the recording power Pw reaches the upper limit Ulim, the recording power Pw becomes constant and the rotation speed V decreases. When the rotation speed V decreases, the recording power Pw has a margin, so that the rotation speed V once decreases to the lowest level, but then increases. When the rotation speed V returns to the normal rotation speed Vn, it becomes constant thereafter, and the recording power Pw becomes the upper limit Uli.
will fall from m.

The state during this time is as shown in the state transition diagram of FIG. 9, and the state changes as S1 → S2 → S1 → S2. As described above, when the recording power is insufficient, the number of revolutions of the disc decreases, and when the recording power has a margin, the number of revolutions of the disc increases, so that the recording power can always be set to a level close to the upper limit. .

In the above embodiment, the B level is used to detect the mark formation status during recording. However, the B level quantity is not necessarily used for the mark formation status during recording. It is not necessary to hire. For example, in the recording laser beam control method described above as the second conventional technique (Japanese Patent Laid-Open No. 4-10237),
The initial intensity of the reproduction signal during the emission of the recording pulse as shown in FIGS. 1 and 2 (VA: before the mark formation process)
And the difference between the latter half intensity (VB: after the mark formation process) is normalized by the initial intensity (VA). Also in the information recording apparatus of the present invention, instead of the amount of B level described above, the initial intensity (VA) and the latter half intensity (VB) of the reproduction signal during the emission of the recording pulse used in the second prior art. It is clear that the same effect can be obtained by using the amount (modulation degree) obtained by normalizing the difference from (after the mark formation process) with the initial intensity (VA).

Fifth Embodiment This fifth embodiment also corresponds to the inventions of claims 1 and 2 . In the above-described fourth embodiment, the case where the rotation speed V serving as the determination reference in the state S2 is the normal rotation speed Vn has been described. In the fifth embodiment, this rotation speed V is
It is characterized in that it is set to Vn2, which is higher than the normal rotation speed Vn. In the fifth embodiment as well, the hardware configuration is the same as that in FIG. 8 described above, but the control by the controller 15 is different.

As in the fifth embodiment, the state S2
When the recording speed Pw has a margin after the recording power Pw is limited to the upper limit Ulim by increasing the rotation speed V, which is the criterion for the judgment, from the normal rotation speed (Vn2> Vn), when the recording power Pw has a margin. Instead of lowering Pw, it is possible to increase the rotation speed V above the normal Vn, so that high-speed recording can be performed. This relationship is shown in the state transition diagram of FIG.

FIG. 11 is a state transition diagram of the controller 15 according to the fifth embodiment. Reference numerals in FIG.
Vn2 indicates a reference rotation speed higher than the normal rotation speed.

The state transition diagram of FIG. 11 is almost the same as the state transition diagram of FIG. 9 described above, but the rotation speed V serving as a criterion for the state S2 is Vn higher than the normal rotation speed Vn.
It is 2. The state S1 is the same as that shown in FIG.
1 (first integrator 13) is turned on, and int2 (second integrator 14) is held. Then, the target power command P
When the relationship between w and the upper limit of power Ulim is Pw <Ulim, the state S1 is maintained, and when Pw ≧ Ulim, the state S2 is set.

In the state S2, conversely, int1 (first integrator 13) is held and int2 (second integrator 14) is held.
Turn on. In this state S2, the relationship between the rotation command value V and the actual rotation speed Vn2 is maintained while V <Vn2,
When the relationship between them becomes V ≧ Vn2, the state S1 is set.
By the controller 15 performing such an operation,
Until the power Pw reaches the upper limit Ulim, the power Pw is controlled according to the comparison result between the target B level and the detected B level, and when the power Pw reaches the upper limit Ulim, the comparison result between the target B level and the detected B level. Thus, the rotation speed V can be controlled.

With this setting, after the recording power Pw is limited by the power upper limit Ulim, if the recording power has a margin, the recording power Pw is not lowered but the disc rotation speed is set to be higher than the normal rotation speed Vn. It becomes possible to raise. Therefore, the recording operation can be performed at a higher speed than in the case of the fourth embodiment. The relationship between the recording power Pw and the rotation speed V in this case is shown in a waveform diagram in FIG.

FIG. 12 is a waveform diagram showing the relationship between the recording power Pw and the rotation speed V based on the state transition of the controller 15 in the fifth embodiment. The horizontal axis of the figure and the symbols of the waveforms are the same as in FIG. 10, and Vn2 indicates a reference rotation speed higher than the normal rotation speed.

Also in the case of FIG. 12, during the state S1,
This is similar to FIG. 10 above. In this state S1, when the recording power Pw reaches the upper limit Ulim, the state is switched to the state S2, the recording power Pw becomes constant, and the rotation speed V decreases. In this state S2, if the recording power Pw has a margin, the disc rotation speed V is increased. In this case, even if the normal rotation speed Vn is reached, if the recording power Pw has a margin, the rotation speed V is further increased, and the rotation speed V is kept until the preset switching reference rotation speed Vn2 is reached. Can be raised.

Here, if the reference rotational speed Vn2 is set to be sufficiently large, it is possible to rotate as fast as possible with the recording power Pw stuck to the upper limit Ulim (maximum power). Therefore, the recording operation can be performed at high speed. If the reference rotational speed Vn2 is set to a value that is too large, head positioning control becomes a problem, so it goes without saying that a value that is as large as possible is selected according to the performance of the apparatus.

In the fifth embodiment and the fourth embodiment described above, either the recording power Pw or the rotation speed V is changed depending on the comparison result between the target B level and the detected B level. The case of controlling has been described. However, both the recording power Pw and the rotation speed V can be variably controlled at the same time depending on the comparison result between the target B level and the detected B level. In this case, both the first integrator 13 and the second integrator 14 shown in FIG. 8 are turned on.
At this time, if the integral gain of the first integrator 13 is set to be higher than the integral gain of the second integrator 14, the recording power can be changed in response to a rapid change in the recording power request (that is, B level change). It can be configured such that Pw follows and the rotary motor follows the slow change in the recording power demand (change in the rotation speed V). Needless to say, the upper limit Ulim is set for the recording power Pw in order to prevent laser destruction.

According to this structure, basically, the operation for increasing the rotational speed V as much as possible is realized in the state where the recording power Pw has reached almost the upper limit Ulim. Then, when the recording power demand is rapidly changed (in this case, the recording power Pw is changed to be lowered), the recording power Pw is promptly controlled. It will be possible to maintain. Also in the fifth embodiment, instead of the amount of B level, the initial intensity (VA) and the latter half intensity (V) of the reproduction signal during the emission of the recording pulse used in the second conventional technique are used.
B: It is possible to use the amount (modulation degree) obtained by normalizing the difference from (after the mark formation process) with the initial intensity (VA). Therefore, the information recording apparatus of the present invention can be used in the case of the embodiment. It is not limited.

In the present invention, during the recording operation, the recording power and the rotational speed of the disc are made variable according to the result of comparison between the level of the reproduction signal from the recording mark and a predetermined value. Therefore, while recording the actual information, the difference in the recording sensitivity in the disc, the laser wavelength fluctuation,
Even if the recording efficiency fluctuates due to a beam positioning error or the like, it is possible to always form a good recording mark. Further, when the recording power is insufficient, the number of revolutions decreases, so that a disc outside the range covered by the laser power can be used, and many types of discs can be handled, improving compatibility. . In addition, low-power lasers can be used, and the power efficiency tolerance range can be widened due to variations in the emission optical system.As a result, it is possible to use inexpensive parts and reduce product costs. Will be realized. In addition, during recording of actual information, if the recording power has a margin, the rotation speed is increased, so that high-speed recording can be performed.

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[Brief description of drawings]

FIG. 1 is a functional block diagram showing an example of an embodiment of the main configuration of an information recording apparatus of the present invention.

FIG. 2 is a flow chart showing a main processing flow of determining the number of rotations at the time of information recording by varying the recording power in the information recording apparatus shown in FIG.

FIG. 3 is a diagram illustrating a β value as one of indexes of reproduced signal quality.

FIG. 4 is a flowchart showing the main processing flow in the information recording apparatus shown in FIG. 1 when the recording power is changed and the number of rotations is determined during information recording according to the second embodiment.

FIG. 5 is a characteristic diagram showing the relationship between the recording power Pw and the index β.

FIG. 6 is a flowchart showing a main processing flow for determining the number of revolutions at the time of information recording by changing the number of revolutions of the disc in the information recording apparatus shown in FIG. 1 according to the third embodiment.

FIG. 7 is a characteristic diagram showing a relationship between a linear velocity and an index β.
The horizontal axis of the figure shows the linear velocity, and the vertical axis shows the index β.

FIG. 8 is a functional block diagram showing an example of a main configuration of a fourth embodiment of the information recording apparatus of the present invention.

FIG. 9 is a state transition diagram of the controller 15 according to the fourth embodiment.

FIG. 10 shows a controller 1 according to the fourth embodiment.
6 is a waveform diagram showing the relationship between the recording power Pw and the rotation speed V based on the state transition of FIG.

FIG. 11 is a state transition diagram of the controller 15 according to the fifth embodiment.

FIG. 12 is a controller 1 according to the fifth embodiment.
6 is a waveform diagram showing the relationship between the recording power Pw and the rotation speed V based on the state transition of FIG.

[Explanation of symbols]

1 disc 2 rotation motor 3 optical head 4 Playback signal detection means 5 Vertical amplitude detection means 6 Laser power control means 7 Rotation control means 8 controller 11 B level detection means 12 Comparator 13 First integrator 14 Second integrator 15 Controller

Claims (2)

(57) [Claims] 1. An information recording apparatus for forming an information recording mark by irradiating a disc with a light beam, and reproducing means for obtaining a reproduction signal at the recording power level emission indicating the information recording mark formation status during a recording operation. An information recording apparatus comprising: comparison means for comparing the level of the reproduction signal with a predetermined value; and control means for varying the power of the light beam and the rotation speed of the disk according to the comparison result. 2. Information recording by irradiating a disk with a light beam
In an information recording apparatus for forming marks, a reproduction signal indicating the information recording mark formation status during the recording operation.
Reproducing means and, comparing means for comparing the level with a predetermined value of the reproduction signal to obtain the No.
If, when the light beam power during a recording operation controlled by the comparison result is within a predetermined range, by varying the power of the light beam by the comparison result,-out <br/> with a predetermined range Is a control for changing the rotation speed of the disk according to the comparison result with the light beam power being a constant value within a predetermined range.
Information recording apparatus comprising: the control means.