JP2002140818A - Device and method for recording by optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk recorder capable of recording information signals on an optical disk while confirming whether the information signals are exactly written or not in comparatively simple configuration. SOLUTION: When irradiating the optical disk with a light beam, reflected light is received and a tracking error signal is detected. In the case of recording, an S-shaped amplitude A1 of the tracking error signal in recording and a maximum value B1 of the tracking error signal in a tracking control state are detected and when the value of B1/A1 exceeds a preset threshold, by controlling the irradiation power of the light beam, so as to suppress it at the time of recording, recording on the optical disk is possible while confirming whether writing is exact or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical disk recording apparatus and a recording method using an optical disk as a recording medium.

[0002]

2. Description of the Related Art With the development of optical information recording technology in recent years, various optical recording / reproducing devices have been developed and have come into widespread use, for example, as storage devices for computers. Optical recording / reproducing devices mainly include, for example, CD-R (CD-Recordable), DVD-
R (DVD-Recordable) or other write-once optical discs that can be recorded only once, or CD-RW (CD-Rewritabl)
e), DVD-RAM, DVD-RW (DVD-Rewritabl)
e), a type using a rewritable optical disk such as a DVD + RW (DVD + Rewritable) that can be recorded many times is known. In these optical recording / reproducing apparatuses (hereinafter, optical disk recording / reproducing apparatuses), an optical head for irradiating a recording surface of the optical disk with a light beam is used to record an information signal on the optical disk.

[0003] When a high-power beam from a semiconductor laser incorporated in an optical head is irradiated via an objective lens along a guide groove (groove or land) provided on a recording surface of an optical disk in advance, once. In a write-once optical disc capable of recording only, a recording layer composed of an organic dye layer is heated and melted by a high-power beam to cause a chemical change, thereby forming a pit and recording an information signal. On the other hand, in the case of an optical disc that can be rewritten a number of times, a so-called phase change method is used, in which the recording layer becomes amorphous due to the rapid heating / cooling action of the beam and another part due to the slow heating / cooling action of the beam. A pit is formed by generating a portion that is in a crystalline state, and an information signal is recorded.

In recording information on such an optical disk, the optical disk recording / reproducing apparatus generally photoelectrically converts return light reflected from the optical disk by a photodetector built in an optical head, and converts the return light into return light. A corresponding signal is generated. Then, based on a servo signal obtained by calculating this signal, a drive current is passed to an actuator that drives the objective lens in two axial directions (focus direction and tracking direction), and the recording surface of the rotating optical disc is The objective lens is driven to follow.

In order for a beam from a semiconductor laser to follow a spiral track defined on a recording surface of an optical disk,
In the servo in the tracking direction for suppressing the deviation between the center of the track and the center of the optical axis of the beam (hereinafter referred to as tracking servo), a signal corresponding to the return light diffracted by the guide groove on the recording surface of the optical disk is generated. A tracking error signal is obtained by calculating the generated signal. The level of this tracking error signal corresponds to the deviation between the center of the track and the center of the optical axis of the beam. That is, when the tracking error signal is 0, the center of the optical axis of the beam is at the center of the track, and the tracking servo performs control so as to secure this state.

Referring to FIG. 6, a conventionally known push-type tracking servo will be described. In this tracking servo, the light receiving surface of the photodetector 8 is divided into four in the track direction and the radial direction of the optical disc (represented as 8a, 8b, 8c, and 8d in the figure, respectively). Signals A and D acquired at light receiving surfaces 8a and 8d for receiving return light P from a closer portion
Is added (A + D), and the light receiving surface 8 for receiving the return light P from the portion near the outer periphery of the track where the information signal is being recorded.
The signals B and C obtained at b and 8c are added (B + C). The output signal obtained by the addition is input to the head amplifier circuit 9, where a tracking error signal corresponding to the difference (A + D)-(B + C) is generated. When the center of the optical axis of the beam is at the center of the track, the difference is zero.

Normally, recording of an information signal is performed from the inner circumference side of the optical disc. When an information signal is recorded on a certain track, an adjacent track on the inner circumference side is already recorded. As a result, the light receiving level on the inner peripheral side is lower than that on the outer peripheral side, whereby the sum of the output signals on the inner peripheral side (A + D) becomes the sum of the output signals on the outer peripheral side (B + C).
Smaller. Therefore, (A + D)-(B + C)
(A + D) and (B + C) are not equal at the center of the track.
In order to correct this, the light beam spot is moved to a position where (A + D) and (B + C) are equal, so that off-track occurs near the inner circumference. Therefore, in practice, pits tend to be formed closer to the inner periphery than the desired position. For example, the offset amount of the pit from the center of the track also differs depending on the material of the layer constituting the optical disk, and it is difficult to manage the offset amount according to the characteristics of the optical disk.

[0008]

By the way, for example, DV
In a high-density recording type optical disc such as a DR or DVD-RAM, a track on a recording surface on which an information signal is recorded is defined by a very narrow pitch, and a margin for the track pitch and the laser spot diameter is very small. Has become smaller. For this reason, it is relatively difficult to match the center of the optical axis of the light beam with the center of the track.
In addition, when the conditions such as the film characteristics of the optical disc and the mechanical characteristics such as surface runout are not good, the center of the optical axis of the light beam may deviate from the center of the track, and pits may not be formed at desired positions. If pits are formed off the track, they affect the tracking servo when recording on an adjacent track that is an unrecorded track, increase crosstalk, and affect jitter (fluctuation in the time axis direction of a digital signal). Or In particular, in the case of a write-once optical disc, the recording sensitivity changes, or the light detector 58 is located between the light receiving faces 58a, 58d facing the inner circumference of the optical disc and the light receiving faces 58b, 58c facing the outer circumference. S / N of push-pull signal (signal to nois
Due to the deterioration of e), the tracking servo may become unstable.

It is known that the recording quality of an information signal on an optical disk depends on an external environment such as temperature and humidity of a drive device at the time of recording and mechanical characteristics such as film characteristics and surface runout of the optical disk. If recording is not performed using irradiation power suitable for these conditions, information signals may not be recorded correctly, and data may not be accurately read during reproduction. Conventionally, in order to avoid such a problem, there has been proposed an optical disk recording / reproducing apparatus having a function of obtaining an optimum irradiation power at the time of recording before recording an information signal on the optical disk. OPC processing (Optimu
m Power Control) is performed. In the OPC process, a predetermined area (PCA (Power Calibration Area)) provided on the optical disc is irradiated while the irradiation power is changed in a plurality of steps, and information signals are continuously recorded. Then, at the time of reproducing the information signal, the irradiation power at which an optimum recording signal can be obtained is determined by using evaluation criteria such as vertical symmetry and amplitude of the reproduced RF signal.

However, even in such OPC processing, the irradiation power is changed in a plurality of steps according to conditions such as the external environment of the drive device and the characteristics of the optical disk at the time of recording, so that pits are not formed at accurate positions. As the irradiation power is increased, the tracking servo performed when recording on an adjacent track, which is an unrecorded track, becomes unstable, and the influence of crosstalk increases, resulting in jitter of an RF signal (radio frequency). There is a problem that is worse.

SUMMARY OF THE INVENTION The present invention has been made in view of the above technical problems, and has a relatively simple configuration, and when recording an information signal, performs recording while confirming whether or not the information signal is correctly written. It is an object of the present invention to provide an optical disk recording device and a recording method capable of guaranteeing recording quality on an optical disk.

[0012]

According to a first aspect of the present invention, there is provided an optical disk recording apparatus for optically recording an information signal on a recording surface of an optical disk, wherein the information signal is recorded along a track defined on the recording surface of the optical disk. A light irradiating means for irradiating a light beam having a predetermined irradiation power, and a light detecting surface for detecting an intensity distribution of light reflected from the optical disk, the light detecting surface comprising at least a light receiving surface of the light beam divided along the track direction of the optical disk Means for detecting the offset amount of the light beam from the center of the track based on the intensity distribution detected by the light detection means, and then adjusting the center of the track to substantially coincide with the center of the optical axis of the light beam. Tracking control means for controlling the irradiation means; and tracking error corresponding to the offset amount of the light beam from the center of the track. Based on the signal, the maximum value A1 of the tracking error signal caused by the light beam during recording to the optical disk crosses at least one track pitch equivalent of the optical disc, the maximum value B of the tracking error signal generated after the control by the tracking control means
Detecting means for detecting the value of 1; calculating means for calculating B1 / A1; and irradiation power control for controlling the irradiation power of the light beam when B1 / A1 exceeds a preset threshold value. Means.

According to a second aspect of the present invention, there is provided an optical disk recording apparatus for optically recording an information signal on a recording surface of an optical disk, wherein a predetermined signal is formed along a track defined on the recording surface of the optical disk. Irradiating means for irradiating a light beam having an irradiating power, light detecting means for detecting an intensity distribution of light reflected from the optical disk, comprising at least a light receiving surface of a light beam divided along a track direction of the optical disk; Based on the intensity distribution detected by the light detecting means, the offset amount of the light beam from the center of the track is detected, and then the irradiating means is tracked so that the center of the track substantially coincides with the center of the optical axis of the light beam. Tracking control means for controlling the tracking error signal corresponding to the offset amount of the light beam from the center of the track. The maximum value A2 of the tracking error signal generated when the light beam traverses at least one track pitch of the optical disk during recording on the optical disk, and the maximum value B1 of the tracking error signal generated after the control by the tracking control means. Detecting means for detecting the light quantity; reflected light quantity detecting means for detecting the total light quantity AS1 of the return light at the time of reproduction with respect to the optical disc; and the total light quantity AS2 of the return light at the time of recording; Ratio of total light amount α (= AS1 / AS2)
Calculating means for approximately calculating the maximum value of the tracking error signal at the time of recording as B1 / (α · A2), and B1 / (α · A2) exceeding a preset threshold value In this case, there is provided an irradiation power control means for controlling so as to suppress the irradiation power of the light beam.

The invention according to claim 3 of the present application is the invention according to claim 1 or 2, further comprising: a dropout detecting means capable of detecting a signal dropout at the time of recording; Determining means for determining whether the detected dropout is caused by an offset of the light beam from the center of the track or a recording operation to an unrecordable area. It was done.

Further, according to a fourth aspect of the present invention, in any one of the first to third aspects of the present invention, the irradiation power control means controls the irradiation power of a predetermined intensity during test recording on an optical disk. During the irradiation, the control process is executed.

According to a fifth aspect of the present invention, there is provided an optical disk recording method for optically recording an information signal on a recording surface of an optical disk, wherein the information signal is recorded along a track defined on the recording surface of the optical disk. An irradiation step of irradiating a light beam having a predetermined irradiation power, and a light detection step of detecting an intensity distribution of light reflected from the optical disk by using at least a light receiving surface of the light beam divided along a track direction of the optical disk. And, based on the light intensity distribution detected in the light detection step, after detecting the offset amount of the light beam from the center of the track, so that the center of the track substantially coincides with the center of the optical axis of the light beam. A tracking control step for performing tracking control, and a tracking error corresponding to an offset amount of the light beam from the center of the track. Based on the signal, the light beam when recording the information signal on the optical disk is the optical disk at least 1
A detection step of detecting a maximum value A1 of a tracking error signal generated by traversing a portion corresponding to a track pitch and a maximum value B1 of a tracking error signal generated after control in the tracking control step;
A calculating step of calculating A1; and an irradiation power control step of controlling the irradiation power of the light beam to be suppressed when B1 / A1 exceeds a preset threshold value. It was done.

Further, the invention according to claim 6 of the present application is directed to an optical disk recording method for optically recording an information signal on a recording surface of an optical disk, wherein the information signal is recorded along a track defined on the recording surface of the optical disk. An irradiation step of irradiating a light beam having a predetermined irradiation power, and a light detection step of detecting an intensity distribution of light reflected from the optical disk by using at least a light receiving surface of the light beam divided along a track direction of the optical disk. And, based on the light intensity distribution detected in the light detection step, after detecting the offset amount of the light beam from the center of the track, so that the center of the track substantially coincides with the center of the optical axis of the light beam. A tracking control step for performing tracking control, and a tracking error signal corresponding to an offset amount of the light beam from the track. The maximum value A2 of the tracking error signal generated when the light beam crosses at least one track pitch of the optical disk when the information signal is recorded on the optical disk, and the maximum value of the tracking error signal generated after the control in the tracking control step. A detecting step for detecting the value B1; a reflected light amount detecting step for detecting the total light amount AS1 of return light at the time of reproduction on the optical disc; and a reflected light amount detecting step of detecting a total light amount AS2 of return light at the time of recording. Ratio of the total amount of return light α (=
AS1 / AS2), a calculation step of approximately calculating the maximum value of the tracking error signal at the time of recording as B1 / (α · A2), and B1 / (α · A2) are preset. An irradiation power control step of controlling the irradiation power of the light beam to be suppressed when the threshold value is exceeded.

Further, the invention according to claim 7 of the present application is the invention according to claim 1 or 2, further comprising: a dropout detecting step capable of detecting a signal dropout at the time of recording; Determining whether the dropout detected in the step is caused by an offset of the light beam from the center of the track or a recording operation to an unrecordable area. It is a characteristic.

Further, in the invention according to claim 8 of the present application, in any one of the inventions according to claims 5 to 7, the irradiation power control step includes the step of controlling the irradiation power of a predetermined intensity at the time of test recording on the optical disk. It is characterized in that it is executed during irradiation.

[0020]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Embodiment 1 FIG. FIG. 1 is a block diagram showing an optical disc recording apparatus according to Embodiment 1 of the present invention. The figure mainly shows a configuration for performing tracking servo and irradiation power control. The recording device 10 includes a spindle motor 2 for rotating the optical disk 1, a semiconductor laser 3 for emitting a beam for irradiating the optical disk 1, a condensing lens 4 for condensing the light of the semiconductor laser 3, and a condensing lens 4 The objective lens 5 that irradiates the light collected in the step on the recording surface of the optical disc 1 in a spot shape, the beam splitter 6 that splits the light reflected from the optical disc 1, and the reflected light is condensed on the photodetector 8. The detection lens 7 and the return light transmitted through the detection lens 7 are photoelectrically converted,
A photodetector 8 for generating an electric signal. In the recording apparatus 10, the components denoted by reference numerals 3 to 8 are integrated to form an optical head (also referred to as an optical pickup).

The recording apparatus 10 amplifies a signal from the photodetector 8 and outputs the amplified signal as a tracking error signal, and a tracking circuit for detecting a tracking error signal generated by the head amplifier circuit 9. It has an error detection circuit 11 and a tracking servo circuit 12 that supplies a drive signal to the optical head in accordance with the detected tracking error signal. Further, the recording device 1
0 indicates that the maximum value (S-shaped amplitude) A1 of the tracking error signal during the recording of the information signal is detected for each light beam irradiation power (irradiation power), and the peak value B1 of the tracking error amount in the tracking servo control state is detected. B1 is used to calculate B1 / A1 from the values of A1 and B1.
/ A1 determination processing circuit 13 and laser power control circuit 1 for controlling irradiation power based on the value of B1 / A1
4 and a laser drive circuit 15 for driving the semiconductor laser 3 based on a control signal from the laser power control circuit 14.

The recording operation of the recording apparatus 10 having the above configuration will be schematically described. The semiconductor laser 3 irradiates the optical disc 1 with a light beam having an intensity corresponding to the current input from the laser drive circuit 15. This light beam is irradiated along a direction perpendicular to the recording surface of the optical disk 1, and is irradiated on the optical disk 1 in a spot shape through a condenser lens 4, a beam splitter 6 and an objective lens 5. If the recording medium is a write-once optical disc,
The recording layer is composed of an organic dye layer. When the intensity of the light beam is equal to or higher than a predetermined value, pits are formed on the recording surface of the optical disc 1. When the intensity of the light beam is lower than the predetermined value, pits are formed. Not done.

The light reflected from the optical disk 1 (hereinafter referred to as “return light”) due to the light beam irradiation enters the beam splitter 6 through the objective lens 5.
In the beam splitter 6, part of the return light is reflected in a direction perpendicular to the incident direction, and is incident on the photodetector 8 through the detection lens 7. In the light detector 8, FIG.
, An output signal corresponding to the difference between the signal obtained on the inner circumference side of the optical disc 1 and the signal obtained on the outer circumference side is generated. This output signal is further
After being input to the head amplifier circuit 9 and amplified, it is input to the tracking error detection circuit 11.

The tracking error detection circuit 11 obtains a tracking error signal by calculating an output signal corresponding to the intensity distribution of the return light detected by the photodetector 8. This tracking error signal is supplied to the tracking servo circuit 12 and the B1 / A determination processing circuit 13
Output to The tracking servo circuit 12 generates a drive signal for driving the objective lens 5 of the optical head based on the input tracking error signal.
In the first embodiment, as is apparent from the configuration of the photodetector 8 described above with reference to FIG. 6, the push-pull method is adopted as the tracking servo, and the light beam is
The tracking control is performed such that the center of the optical axis is moved in a direction coinciding with the center of the track, that is, in a direction in which the tracking error signal decreases.

The B1 / A1 determination processing circuit 13 calculates the peak value B1 of the tracking error amount in the tracking servo control state in order to monitor the offset amount of the light beam with respect to the track center in the tracking servo control state during the recording of the information signal. To detect. Further, the B1 / A1 determination processing circuit 13 detects the maximum tracking error (S-shaped amplitude) A1 during recording of the information signal for each irradiation power. Since the tracking error maximum value A1 is an off-track amount corresponding to a pitch of one track, the off-track amount can be accurately monitored by calculating B1 / A1. Note that the B1 / A1 determination processing circuit 13 may set the tracking error maximum value A1 in advance without detecting it for each irradiation power.

In the B1 / A1 determination processing circuit 13, a threshold value of B1 / A1 is set, and the calculated B1 / A1 is determined based on the threshold value. The threshold value of B1 / A1 can be set arbitrarily. Then, when the calculated B1 / A1 exceeds a preset threshold value, the laser power control circuit 14 is controlled so that the irradiation power is suppressed. For example, when the threshold value of B1 / A1 is set to 0.4,
When the calculated B1 / A1 exceeds 0.4, a command signal is issued to the laser power control circuit 14 to lower (or stop) the irradiation power by 0.5 mW.

For example, as described above, the level of the irradiation power can be controlled by changing the threshold value of B1 / A1 according to the tracking servo gain or the occurrence of vibration. Thus, when the pits gradually go off-track in the tracking direction under unfavorable conditions such as external vibrations and resonance of the optical disk, by reducing or stopping the irradiation power instantaneously, undesired pits are formed. It is possible to prevent the problem that the recording is not performed accurately. Further, by controlling the irradiation power level P0, thermal interference and heat accumulation of the pits formed on the recording surface of the optical disk are reduced, and desired pits are formed. As a result, stable recording quality can be ensured in the recording operation. In particular, in the case of a write-once optical disc, writing twice is not allowed as in a rewritable optical disc.
This effect is very beneficial.

FIG. 2 is a diagram showing a relationship between a signal waveform used when recording an information signal in the optical disk recording apparatus 10 and a pit shape formed on a recording surface. A case where a write-once optical disc DVD-R is used as a recording medium will be described. 2A shows recording data, and FIG. 2B shows a recording pulse of irradiation power for irradiating the optical disc 1. The mark section of the recording pulse is composed of a top pulse 20 and a multi-pulse train 21 along the time axis direction, and is composed of a combination of a top pulse width (3T) and a channel clock period (T) according to the recording data length. . The multi-pulse train 21 extends from a position delayed by 3T from the rising edge of the recording data to the trailing edge of the recording data. The shape of the pits formed on the optical disc 1 differs depending on the level (P0) of the irradiation power of the recording data.

FIG. 2C shows the shapes of pits formed along the tracks of the optical disc 1 according to various levels of the irradiation power. The tracks and pits of the optical disc 1 are actually curved at a predetermined curvature, but are drawn in a substantially straight line in this figure for simplification of the drawing. In this embodiment, a DVD-R is used as a recording medium, and pits are formed by thermal energy of irradiation power. When the irradiation power level P0 is optimally set, desired pits 25 are formed. On the other hand, when the irradiation power level P0 is too low,
A pit 23 that does not reach the prescribed width is formed.
If the level P0 is too high, pits 24 exceeding the specified width are formed. When these pits 23 and 24 are formed, there is a fear that the recording layer or the reflective layer composed of the organic dye layer may be damaged, or the recording may be offset by the influence of an adjacent track.

The optimum irradiation power for forming the desired pits 25 changes according to various conditions such as the recording sensitivity of the optical disk 1, the laser wavelength of the drive device for recording, and the light beam intensity. In the device 10, the OPC process is performed before the necessary information signal is recorded. In the OPC process, a predetermined area (PCA) provided on the optical disc 1 is irradiated while the irradiation power is changed in a plurality of steps, and information signals are continuously recorded. Then, at the time of reproducing the information signal, using the evaluation criteria such as the vertical symmetry and the amplitude of the reproduced RF signal,
Irradiation power for obtaining an optimum recording signal is required.

FIG. 3 is a flowchart of the OPC process. In the OPC process, the optical disc 1 is
It is executed every time it is set to 0. In this flow, first, the range of the irradiation power in the PCA is set (S1).
1). For example, when the optimal irradiation power is 10 mW,
The drive device sets in advance to record and reproduce from 8 mW to 12 mW every 1 mW. Next, pits are formed in the PCA (S12). At this time, as the recording pulse waveform, parameter data stored in the optical disk in advance or parameters stored in the memory in the optical disk recording device 10 are used.

Subsequently, the return light from the optical disk 1 during recording is detected by the photodetector 8 (S13), and a tracking error signal during recording is detected (S14). Thereafter, the maximum values A1 and B1 of the tracking error signal at this time are detected and B1 / A1 is calculated (S15). Then, it is determined whether or not the calculated B1 / A1 is within the allowable range (S16). As a result, if the calculated B1 / A1 is within the allowable range, the process proceeds to S17, and on the other hand, the calculated B1 / A1
Is not within the allowable range, the irradiation power is instantaneously limited (that is, the irradiation power is reduced or stopped), and the process proceeds to S20.

In S17, it is determined whether or not recording in the range of the irradiation power set in S11 has been completed. As a result, when it is determined that the recording has been completed, the process proceeds to S19. On the other hand, when it is determined that the recording has not been completed, the power of the pulse train is increased by one unit, and then the process proceeds to S12.
Repeat the following steps.

In S19, the optimum irradiation power is detected from the set irradiation power. Thereafter, the information signal recorded in S12 is continuously reproduced (S20). The jitter measurement or the asymmetry measurement is performed, the optimum irradiation power is obtained, and the OPC process ends (S21). S18
In the case where the irradiation power is limited, the recording operation is interrupted in the middle, so that as the optimum irradiation power, jitter or asymmetry should be selected from the recorded irradiation power to select a better irradiation power. I do.

In the running OPC process for a write-once optical disc such as a CD-R or DVD-R, the reflected light intensity during the OPC process and the reflected light intensity during recording are usually compared. The recording is performed while correcting based on the light beam intensity obtained at the time of the processing. In the running OPC processing, if the B1 / A1 determination processing circuit 13 is employed, the optimum irradiation power for performing the recording on the optical disc 1 is obtained. By performing the test recording by using the irradiation power of a predetermined intensity, the irradiation power is limited so that the recording quality in the running OPC process can be guaranteed.

Next, another embodiment of the present invention will be described. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and further description is omitted. Embodiment 2 FIG. FIG. 4 is a block diagram showing a configuration of an optical disc recording apparatus according to Embodiment 2 of the present invention. As in FIG. 1 showing Embodiment 1, mainly the tracking control unit and the irradiation power control unit are shown. The configuration is shown. In the first embodiment, as in the rewritable type, it is possible to start the recording on the disk after detecting the maximum value of the tracking error (S-shaped amplitude) by performing the tracking off once with the irradiation power, but the write-once type. Optical discs do not allow overwrite recording like rewritable optical discs,
When test recording such as OPC processing is performed, the writable capacity of the optical disk is reduced. Therefore, it is preferable that the OPC processing be limited.

In the second embodiment, the B1 / (α · A2) determination processing circuit 33 is provided to monitor the offset amount of the laser with respect to the center of the track in the tracking servo state at the time of recording. This B1 / (α · A
2) The determination processing circuit 33 detects the peak value B1 of the tracking error amount in the tracking servo control state in order to monitor the offset amount with respect to the track center in the tracking servo control state during recording. Also, B1
In the / (α · A2) determination processing circuit 33, the tracking error maximum value (S-shaped amplitude) A2 at the time of reproduction is determined so that the tracking servo is turned off in order to count the tracks when accessing a predetermined position on the optical disk. Since the operation is performed, it is easily detected. This A2 needs to be converted into an off-track amount during recording based on an off-track amount corresponding to one track pitch during reproduction.

In the second embodiment, in order to convert A2 into an off-track amount at the time of recording, a reflected light amount detection circuit 32 capable of detecting the amount of return light from the output signal from the head amplifier circuit 9 is provided. Have been. The reflected light amount detection circuit 32 detects the total amount of light reflected from the optical disk 1 during recording and reproduction based on an output signal from the head amplifier circuit 9. Set the amount of return light during recording to AS
1. Assuming that the total amount of return light during reproduction is AS2, the return light amount ratio α can be obtained from α = AS1 / AS2. By using this α, the maximum value (S-shaped amplitude) of the tracking error signal at the time of recording is (α
A2) can be approximated. That is, at the time of access, the maximum tracking error value during reproduction (amplitude at S) A
2 and the total light amount AS2 at the time of reproduction are detected and stored. Since the total light amount AS1 is detected during recording, α = A during recording.
S1 / AS2 is determined. Thereby, B1 / (α · A2) can be calculated as an approximate value of the maximum value (S-shaped amplitude) of the tracking error signal at the time of recording. This makes it possible to accurately monitor the off-track amount of the laser with respect to the center of the track.

In the B1 / (α · A2) determination processing circuit 13, a threshold value of B1 / (α · A2) is set.
(Α · A2) is determined. The threshold value of B1 / (α · A2) can be set arbitrarily. Then, the calculated B1
When / (α · A2) exceeds a preset threshold,
The laser power control circuit 14 is controlled so that the irradiation power is suppressed. For example, when the threshold value of B1 / A1 is set to 0.4, the calculated B1 / A1
Exceeds 0.4, a command signal is issued to the laser power control circuit 14 so as to reduce (or stop) the irradiation power by 0.5 mW.

As described above, by changing the threshold value of B1 / (α · A2), the level of the irradiation power can be controlled, and particularly under the unfavorable conditions such as external vibration and optical disk resonance. In the case where the pits gradually go off-track in the tracking direction, by reducing or stopping the irradiation power instantaneously, it is possible to prevent the occurrence of a problem that undesired pits are formed and recording is not performed accurately. Can be. As a result, stable recording quality can be ensured in the recording operation.

Embodiment 3 FIG. 5 is a block diagram showing a configuration of an optical disc recording apparatus according to Embodiment 3 of the present invention. Similar to FIG. 1 showing the first embodiment, mainly the configurations of a tracking control unit and an irradiation power control unit are shown. In the third embodiment, a drop-out detection circuit 42 is provided for detecting a signal drop-out from the output signal of the head amplifier circuit 9 (a decrease in the output signal level during recording data reproduction causes a process error). Have been. In the dropout detection circuit 42, during recording, if there is an unrecordable area due to scratches on the light beam incident surface of the optical disc, adhesion of dust, defects in the recording layer, etc., the light reflected from that area A dropout of the acquired signal is detected. The detection of such a dropout can be determined by the signal level of the return light at the time of recording. Dropout is detected when the level of the return light exceeds an arbitrarily settable threshold. In the dropout detection section, the recording operation is suspended, and the servo is held at the value before detection.
Then, after the end of the dropout section is detected, the recording operation is started again.

When the pits are formed only in the section where the pit is offset, since it is not detected that only the dropout is detected, the pit is recorded as it is in the offset section.
Recording quality will be degraded. In order to cope with this, in the third embodiment, the determination circuit 16 is provided which can determine the cause of the dropout by utilizing the fact that the offset amount can be monitored during recording. That is, in the determination circuit 19, based on the output signals from the dropout detection circuit 42 and the tracking error detection circuit 11, the dropout is caused by the offset of the light beam from the center of the track or the recording operation in the unrecordable area. It is determined which one is the cause. As a result, more accurate dropout determination can be performed in the recording operation, and recording accuracy can be improved.

The present invention is not limited to the illustrated embodiment, and it goes without saying that various improvements and design changes can be made without departing from the spirit of the present invention.

[0044]

As is clear from the above description, according to the first aspect of the present invention, in an optical disk recording apparatus for optically recording an information signal on a recording surface of an optical disk, the center of the track of the optical disk is measured. Based on the tracking error signal corresponding to the offset amount of the light beam,
Detection for detecting a maximum value A1 of a tracking error signal generated when a light beam crosses at least one track pitch of the optical disk during recording on the optical disk and a maximum value B1 of a tracking error signal generated after control by the tracking control means. Means and B1 /
A calculation means for calculating A1 and an irradiation power control means for controlling the irradiation power of the light beam when B1 / A1 exceeds a preset threshold value are provided. With this configuration, at the time of recording on the optical disk, recording can be performed while confirming whether or not the information signal is correctly written. As a result, stable recording quality on the optical disc can be guaranteed.

According to the invention of claim 2 of the present application, in an optical disk recording apparatus for optically recording an information signal on a recording surface of an optical disk, the information signal corresponds to the offset amount of the light beam from the center of the track of the optical disk. Based on the tracking error signal, the maximum value A2 of the tracking error signal generated when the light beam crosses at least one track pitch of the optical disk at the time of recording on the optical disk and the maximum value B1 of the tracking error signal generated after the tracking control are determined. Detecting means for detecting;
Total light amount AS1 of return light at the time of reproduction from the optical disk
A reflected light amount detecting means for detecting the total light amount AS2 of the return light at the time of recording, and a ratio α (= AS1 / AS2) of the total light amount of the return light at the time of reproduction and recording of the optical disk. The maximum value of the tracking error signal at the time is B1 / (α ·
A2) an operation means for approximately calculating as A2), and B1 / (α
An irradiation power control means for controlling the irradiation power of the light beam when A2) exceeds a preset threshold value is provided;
When recording on an optical disc, recording can be performed while confirming whether or not the information signal is correctly written. As a result, stable recording quality on the optical disc can be guaranteed. Further, according to the present invention, the irradiation power of the light beam suitable for recording can be obtained without the need for test recording, so that the recording operation can be simplified.

Further, according to the invention of claim 3 of the present application, further, a dropout detecting means for detecting a dropout of a signal at the time of recording, and a dropout detected by the dropout detecting means, Determination means for determining whether the operation is caused by an offset of the light beam from the center of the light beam or a recording operation to an unrecordable area is provided, so that the recording operation to the unrecordable area is avoided. And stable recording can be performed on the optical disc.

Further, according to the invention according to claim 4 of the present application, the irradiation power control means executes the control processing while irradiating a predetermined intensity of irradiation power during test recording on the optical disk. , The recording quality in the OPC process can be guaranteed.

According to a fifth aspect of the present invention, in an optical disk recording method for optically recording an information signal on a recording surface of an optical disk, an offset amount of a light beam from a center of a track of the optical disk is determined. Based on the corresponding tracking error signal, the maximum value A1 of the tracking error signal generated when the light beam crosses at least one track pitch of the optical disk when the information signal is recorded on the optical disk, and the maximum value of the tracking error signal generated after the tracking control. When the maximum value B1 is detected, B1 / A1 is calculated, and when B1 / A1 exceeds a preset threshold, control is performed so as to suppress the irradiation power of the light beam. , Record while checking whether the information signal is written correctly It can be. As a result, stable recording quality on the optical disc can be guaranteed.

According to a sixth aspect of the present invention, in an optical disk recording method for optically recording an information signal on a recording surface of an optical disk, the method corresponds to an offset amount of a light beam from a track of the optical disk. Based on the tracking error signal, the maximum value A2 of the tracking error signal generated when the light beam crosses at least one track pitch of the optical disk when the information signal is recorded on the optical disk, and the tracking generated after the control in the tracking control step. The maximum value B1 of the error signal is detected, the total light amount AS1 of the return light at the time of reproduction to the optical disc and the total light amount AS2 of the return light at the time of recording are detected, and the total amount of the return light at the time of reproduction and recording is detected. Light amount ratio α (= A
After calculating S1 / AS2), the maximum value of the tracking error signal at the time of recording is approximately calculated as B1 / (α · A2), and B1 / (α · A2) is set to a predetermined threshold value. If it exceeds, control is performed so as to suppress the irradiation power of the light beam, so that it is possible to perform recording while confirming whether or not the information signal is correctly written when recording on the optical disc. As a result, stable recording quality on the optical disc can be guaranteed. Further, according to the present invention, the irradiation power of the light beam suitable for recording can be obtained without the need for test recording, so that the recording operation can be simplified.

Further, according to the invention according to claim 7 of the present application, further, a dropout of a signal at the time of recording is detected, and the detected dropout is an offset of the light beam from the center of the track or the recording. Since it is determined which of the recording operations to the unrecordable area is caused, the recording operation to the unrecordable area can be avoided, and stable recording can be performed on the optical disc.

Further, according to the invention of claim 8 of the present application, the irradiation power control step is executed while irradiating a predetermined intensity of irradiation power at the time of test recording on the optical disk. Recording quality can be guaranteed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an optical disc recording device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a signal waveform used for recording an information signal by the optical disc recording apparatus and a mark shape formed on a recording surface.

FIG. 3 is a block diagram illustrating a configuration of an optical disc recording device according to a second embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of an optical disc recording device according to a third embodiment of the present invention.

FIG. 5 is a flowchart of an OPC process according to Embodiment 4 of the present invention.

FIG. 6 is an explanatory diagram conceptually showing a conventionally known push-pull tracking servo.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Optical disk 2 ... Spindle motor 3 ... Semiconductor laser 4 ... Condensing lens 5 ... Objective lens 6 ... Beam splitter 7 ... Detection lens 8 ... Photodetector 8a, 8d ... Light receiving surface on the inner peripheral side of an optical disk 8b, 8c ... Outer periphery of an optical disk 9: Head amplifier circuit 10: Laser drive circuit 11: Tracking error detection circuit 12: Tracking servo circuit 13: B1 / A1 determination processing circuit 14: Laser power control circuit 15: Laser drive circuit 32: Reflected light amount detection circuit 33: B1 / (α · A2) determination processing circuit 42: dropout detection circuit 43: determination circuit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kenji Koishi 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5D090 AA01 BB04 CC02 DD03 EE03 KK03 5D118 AA16 BA01 BB02 BF03 CD03 CD11 CF03 CF06 CG02 5D119 AA23 BA01 BB03 DA01 EA02 HA44

Claims (8)

[Claims] 1. An optical disk recording apparatus for optically recording an information signal on a recording surface of an optical disk, comprising: an irradiation device for irradiating a light beam having a predetermined irradiation power along a track defined on the recording surface of the optical disk. Means, at least a light receiving surface of a light beam divided along a track direction of the optical disc, a light detecting means for detecting an intensity distribution of light reflected from the optical disc, and an intensity distribution detected by the light detecting means. A tracking control unit that performs tracking control on the irradiation unit so that the center of the track and the center of the optical axis of the light beam substantially coincide with each other after detecting an offset amount of the light beam from the center of the track; Based on the tracking error signal corresponding to the offset amount of the light beam from the center, the light Detecting means for detecting a maximum value A1 of a tracking error signal generated when the laser beam crosses at least one track pitch of the optical disk, and a maximum value B1 of the tracking error signal generated after control by the tracking control means; Calculating means for calculating / A1, when B1 / A1 exceeds a preset threshold value,
An optical disc recording apparatus, comprising: an irradiation power control unit that controls so as to suppress the irradiation power of the light beam. 2. An optical disk recording apparatus for optically recording an information signal on a recording surface of an optical disk, comprising: an irradiation device for irradiating a light beam having a predetermined irradiation power along a track defined on the recording surface of the optical disk. Means, at least a light receiving surface of a light beam divided along a track direction of the optical disc, a light detecting means for detecting an intensity distribution of light reflected from the optical disc, and an intensity distribution detected by the light detecting means. A tracking control unit that performs tracking control on the irradiation unit so that the center of the track and the center of the optical axis of the light beam substantially coincide with each other after detecting an offset amount of the light beam from the center of the track; Based on the tracking error signal corresponding to the offset amount of the light beam from the center, the light Detecting means for detecting a maximum value A2 of a tracking error signal generated when the laser beam crosses at least one track pitch of the optical disk, and a maximum value B1 of a tracking error signal generated after control by the tracking control means; Total light amount AS1 of return light at the time of reproduction from the optical disk
A reflected light amount detecting means for detecting the total light amount AS2 of the return light at the time of recording; and a ratio α of the total light amount of the return light at the time of reproduction and recording of the optical disk.
(= AS1 / AS2), and calculating means for approximately calculating the maximum value of the tracking error signal at the time of recording as B1 / (α · A2), and B1 / (α · A2) are preset. An irradiation power control unit for controlling the irradiation power of the light beam when the threshold value exceeds the threshold value. 3. A dropout detecting means for detecting a dropout of a signal at the time of recording, and a dropout detected by the dropout detecting means,
3. The apparatus according to claim 1, further comprising: a determination unit configured to determine whether the light beam is caused by an offset of a light beam from a center of a track or a recording operation on an unrecordable area. An optical disc recording apparatus according to claim 1. 4. The method according to claim 1, wherein said irradiation power control means executes a control process while irradiating a predetermined intensity of irradiation power during test recording on an optical disk. An optical disc recording apparatus according to claim 1. 5. An optical disk recording method for optically recording an information signal on a recording surface of an optical disk, comprising: irradiating a light beam having a predetermined irradiation power along a track defined on the recording surface of the optical disk. A light detecting step of detecting an intensity distribution of light reflected from the optical disk using at least a light receiving surface of the light beam divided along a track direction of the optical disk; and a light detected in the light detecting step. A tracking control step of detecting the offset amount of the light beam from the center of the track based on the intensity distribution, and performing tracking control so that the center of the track and the center of the optical axis of the light beam substantially coincide with each other; Information signal to the optical disk based on the tracking error signal corresponding to the offset amount of the light beam from the optical disk. For detecting a maximum value A1 of a tracking error signal generated by a light beam traversing at least one track pitch of the optical disc at the time of recording, and a maximum value B1 of a tracking error signal generated after control in the tracking control step. A step of calculating B1 / A1; and a step of calculating B1 / A1 when B1 / A1 exceeds a preset threshold value.
An irradiation power control step of controlling the irradiation power of the light beam to be suppressed. 6. An optical disk recording method for optically recording an information signal on a recording surface of an optical disk, comprising: irradiating a light beam having a predetermined irradiation power along a track defined on the recording surface of the optical disk. A light detecting step of detecting an intensity distribution of light reflected from the optical disk using at least a light receiving surface of the light beam divided along a track direction of the optical disk; and a light detected in the light detecting step. A tracking control step of detecting the offset amount of the light beam from the center of the track based on the intensity distribution, and performing tracking control so that the center of the track and the center of the optical axis of the light beam substantially coincide with each other; Based on the tracking error signal corresponding to the offset amount of the light beam, the information signal is recorded on the optical disc. A detection step for detecting a maximum value A2 of a tracking error signal generated when the light beam crosses at least one track pitch equivalent of the optical disk, and a maximum value B1 of the tracking error signal generated after the control in the tracking control step. The total amount of return light AS1 upon reproduction from the optical disk,
A reflected light amount detecting step of detecting the total light amount AS2 of the return light at the time of recording; and a ratio α (= AS) of the total light amount of the return light at the time of the reproduction and the recording.
1 / AS2), and a calculation step of approximately calculating the maximum value of the tracking error signal at the time of recording as B1 / (α · A2); and B1 / (α · A2) is set in advance. An irradiation power control step of controlling the irradiation power of the light beam to be suppressed when the threshold value is exceeded. 7. A dropout detecting step capable of detecting a dropout of a signal at the time of recording, and the dropout detected in the dropout detecting step is determined by an offset of a light beam from a center of a track or a recording failure. 7. The optical disk recording apparatus according to claim 5, further comprising: a determination step of determining which of the recording operations is performed in a possible area. 8. The optical disk recording according to claim 5, wherein the irradiation power control step is performed during irradiation of a predetermined intensity of irradiation power during test recording on the optical disk. Method.