JP2005259227A - Optical information recording and reproducing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical information recording and reproducing device which does not require readjustment from scratch and makes a quick adjustment without becoming unadjustable even if a disturbance occurs. <P>SOLUTION: The optical information recording and reproducing device is provided with; a reproduction signal amplitude measuring circuit 13 which measures the amplitude of an reproduction signal; an offset generation circuit 12 which sets the offset of a servo control means based on the reproduction amplitude thus measured; and a correction circuit 14 which corrects a reproduction signal amplitude, during measuring the reproduction signal amplitude, according to the size of a focus error signal having a correlation with the reproduction signal amplitude. In addition, the reproduction signal amplitude is corrected, during measuring the reproduction signal amplitude, according to the size of a focus error signal having a correlation with the reproduction signal amplitude when adjusting a parameter such as reproduction power and the like relating to recording or reproduction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical information recording / reproducing apparatus for recording information on an information recording medium such as an optical disk or reproducing the recorded information, and in particular, various parameters such as servo offset and reproduction power are optimal values based on reproduction signal quality. The present invention relates to a technique for dealing with disturbances during reproduction quality measurement in the case of determining the level of reproduction.

  Conventionally, in such an optical information recording / reproducing apparatus, in order to position the light spot in an optimum state on the information track, the offset of control such as focus and tracking is set to maximize the amplitude of the information reproducing signal or minimize the jitter. It has been adjusted to such a point. For example, Japanese Patent Laid-Open No. 8-7311 discloses a case where astigmatism occurs when the focus offset is sequentially changed to obtain a focus offset that maximizes the amplitude of the information reproduction signal and is given to the focus control unit. A method of always performing optimum focus control is described (Patent Document 1).

This conventional method does not describe a method for dealing with a disturbance caused by vibration or the like when the amplitude of the reproduction signal is measured by sequentially changing the focus offset. Japanese Laid-Open Patent Publication No. 2002-228561 describes that when a disturbance is detected by vibration detection or the like, the adjustment is restarted from the beginning (Patent Document 2).
JP-A-8-7311 JP-A-8-287494

  In the method of re-adjusting from the beginning when a disturbance is detected during measurement of the reproduction quality such as the amplitude of the reproduction signal as in Patent Document 2, the adjustment time becomes long, and in particular, many adjustments are performed when the drive is started. There was a problem that the startup time of the drive became long. In addition, when an optical disk device is installed in a portable device such as a video camera or music player, the operation may be repeated each time depending on the relationship between the period of intermittent disturbance caused by the movement of the operating person, walking, running, etc., and the adjustment time. In the worst case, the adjustment did not converge.

  The present invention has been made in view of the above-mentioned conventional problems, and the purpose thereof is an optical that can be adjusted quickly without being redone from the beginning or being unable to be adjusted even when there is a disturbance. An object is to provide an information recording / reproducing apparatus.

  In order to achieve the above object, the present invention irradiates an information recording medium with spot light and receives reflected light from the recording medium to record information or reproduce recorded information. A light receiving element for receiving reflected light from the recording medium, a means for detecting a servo error signal based on a light receiving signal of the light receiving element, a means for performing servo control based on the servo error signal, and the light receiving Means for detecting a reproduction signal based on a light reception signal of the element; means for measuring a reproduction index indicating the quality of the reproduction signal; and setting an offset of the servo control means based on the reproduction index measured by the measurement means And means for correcting the reproduction index according to the magnitude of a predetermined error signal having a correlation with the reproduction index.

  The present invention also provides an optical information recording / reproducing apparatus for irradiating an information recording medium with spot light and receiving reflected light from the recording medium to record information or reproduce recorded information. A light receiving element that receives reflected light from the light receiving means, a means for detecting a reproduction signal based on a light reception signal of the light receiving element, a means for measuring a reproduction index indicating the quality of the reproduction signal, and a measurement means It is characterized by comprising means for adjusting parameters relating to information recording or reproduction based on the reproduction index, and means for correcting the reproduction index in accordance with the magnitude of a predetermined error signal correlated with the reproduction index.

  In the above configuration, when a disturbance such as vibration occurs during measurement of the reproduction index indicating the reproduction quality for determining the offset of the servo control means or the adjustment amount of the parameter adjustment means, the amount of the disturbance is determined as a predetermined error signal. Further, by correcting the reproduction index being measured in accordance with the obtained size, it is possible to minimize the influence of disturbance and to perform quick adjustment without having to redo the adjustment.

  According to the present invention, in various servo offset adjustment operations such as focus offset adjustment and tracking offset adjustment, or adjustment to obtain the optimum point by measuring the quality of the reproduction signal, such as spherical aberration amount adjustment, reproduction power adjustment, equalization filter adjustment, Reproduce signal quality indicators such as amplitude, jitter, and error rate of the reproduction signal according to the magnitude of the focus error signal, tracking error signal, lens position signal, spherical aberration error signal, etc. By correcting with the correction table and the correction function, the influence of disturbance can be suppressed to the minimum, and quick adjustment without having to redo the adjustment can be performed.

  Next, the best mode for carrying out the invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a first embodiment of an optical information recording / reproducing apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes an optical disc as an information recording medium, and 2 denotes an optical pickup unit for irradiating the optical disc 1 with a light beam and detecting reflected light to record information or reproduce recorded information. The optical pickup unit 2 includes a semiconductor laser as a light source, an objective lens for condensing the laser beam on the disc, a photosensor for receiving reflected light from the optical disc 1, a focus actuator or objective lens for driving the objective lens in the focus direction. It consists of a tracking actuator that drives in the tracking direction.

  Reference numeral 3 denotes a detection circuit that converts the outputs of a plurality of light receiving elements constituting the optical sensor in the optical pickup unit 2 into electrical signals. Reference numeral 4 denotes a focus error generation circuit that generates a focus error signal from the output signal of the detection circuit 3. An offset addition circuit 5 applies an offset to the focus servo loop, and a phase compensation circuit 6 performs phase compensation of the focus servo loop. A focus driver 7 drives a focus actuator in the optical pickup unit 2.

  Further, 8 is a tracking error generation circuit that generates a tracking error signal based on the output of the detection circuit 3, 9 is an offset addition circuit that applies an offset in the tracking servo loop, and 10 is a phase that performs phase compensation of the tracking servo loop. A compensation circuit 11 is a tracking driver that drives a tracking actuator in the optical pickup unit 2. Reference numeral 12 denotes an offset generation circuit that generates an offset to be applied to the focus servo loop and the tracking servo loop. Reference numeral 13 denotes an output signal (reproduction signal) from the detection circuit 3, that is, a reproduction signal for measuring the amplitude of the reproduction signal reproduced from the optical disc 1. An amplitude measurement circuit, 14 is a correction circuit, 15 is a controller for controlling each unit, and 16 is a spindle motor that rotationally drives the optical disk 1.

  The optical disk 1 is fixed to a spindle motor 16 and rotates at a predetermined rotational speed. Laser light emitted from a semiconductor laser (not shown) in the optical pickup unit 2 is condensed on the optical disk 1 by the objective lens, and reflected light reflected from the optical disk 1 passes through the objective lens in the optical pickup unit 2 again. Light is received by an optical sensor composed of a plurality of light receiving elements.

  Outputs of a plurality of light receiving elements constituting the optical sensor are converted into electrical signals by the detection circuit 3 and input to the focus error generation circuit 4 and the tracking error generation circuit 8. A focus error signal is generated from the plurality of electrical signals from the detection circuit 3 by a predetermined calculation process in the focus error generation circuit 4. Similarly, a tracking error signal is generated by a predetermined calculation process in the tracking error generation circuit 8. The predetermined calculation processing is, for example, the difference between the sums of the diagonals of the four-part light receiving element by the astigmatism method in the case of focus, and the sum of the sums in the track direction of the four-part light receiving element in the push-pull method for tracking The error signal may be detected by any method.

  In addition, the output signal (reproduction signal) of the detection circuit 3 is input to a reproduction signal processing circuit (not shown), and information recorded on the optical disc 1 is reproduced by this circuit. The reproduction signal is input to the reproduction signal amplitude measuring circuit 13 and the reproduction signal amplitude is measured as described above.

  The focus error signal output from the focus error generation circuit 4 is added with a predetermined offset by the offset addition circuit 5 and input to the phase compensation circuit 6. The focus error signal to which the offset is added is also input to the correction circuit 14. The signal phase-compensated by the phase compensation circuit 6 is input to the focus driver 7, the focus actuator in the optical pickup unit 2 is driven, and focus servo control is performed to focus the light spot on the information surface of the optical disk 1.

  On the other hand, the tracking error signal output from the tracking error generation circuit 8 is added with a predetermined offset by the offset addition circuit 9 and input to the phase compensation circuit 10. The signal compensated by the phase compensation circuit 10 is input to the tracking driver 11, and a tracking actuator (not shown) in the optical pickup unit 2 is driven to perform tracking servo control so that the light spot follows the information track of the optical disk 1. Let

  Next, the optimum tracking offset adjustment method according to the present embodiment will be described with reference to the flowchart of FIG. The optimum tracking offset adjustment is performed in a state where focus and tracking control are applied in the same manner as in the normal mode on an adjustment track on which a predetermined signal is recorded in advance.

  It is assumed that the optimum focus offset adjustment has been completed before performing this adjustment, and the offset generation circuit 12 supplies the focus offset adjustment value to the offset addition circuit 5. The value to be added is 0 before adjustment.

  The controller 15 starts the adjustment operation in synchronization with the rotation synchronization signal from the spindle motor 16. First, an initial track offset amount is given to the offset generation circuit 12 (S201). The offset generation circuit 12 can give different offsets to tracking and focus. The focus offset amount is fixed to a predetermined value except during the focus offset adjustment including the tracking offset adjustment. The focus offset amount has been adjusted since the adjustment has already been completed. Next, during a certain period, the output of the reproduction signal amplitude measurement circuit 13 is integrated into a memory (not shown) in the controller 15 via the correction circuit 14 (S202, S203). The correction method of the correction circuit 14 will be described in detail later.

  The fixed period is set to a time of about 1/10 of one rotation of the spindle motor 16 so that the offset process can be performed within one rotation. For example, if the rotation speed of the spindle motor 16 is 25 Hz, one rotation is 40 mS, and the fixed period is about 4 mS. This value may be set appropriately according to the item to be adjusted. In the tracking offset adjustment of this embodiment, this time is set in consideration of the response time of the servo after the offset is changed.

  The reproduction signal amplitude measurement circuit 13 measures and outputs the amplitude of the reproduction signal every predetermined period. For example, the amplitude can be detected by applying a reproduction signal to a peak hold circuit and a bottom hold circuit (not shown). The predetermined period is appropriately determined by a period equal to or higher than the signal frequency recorded on the adjustment track of the optical disc 1. For example, if a signal of about 10 MHz is recorded on the adjustment track, the amplitude can be measured if the predetermined period is 0.1 μs or more. For example, if the period is 1 μs and the offset one step is about 4 ms, 4000 points can be integrated.

  Thereafter, the controller 15 determines whether or not the ninth process has been completed (S204). If the ninth process has not been reached, the tracking offset amount is changed (S205), and the process returns to S202 again. Thereafter, the same processing is repeated with the offset amount changed, and the process is terminated when the ninth time is reached in S204. Here, the amount of offset is set to an appropriate range in consideration of the adjustment range, and is divided into eight equal parts from the minimum value to the maximum value around electrical zero. For example, it is set to be 0.01 μm from −0.04 μm to 0.04 μm.

  Next, the controller 15 detects the offset amount with the largest reproduction amplitude from the nine integrated data, sets it in the offset generation circuit 12, and ends the adjustment process (S206).

  Next, a correction method of the correction circuit 14 will be described. FIG. 3 is a diagram showing a standard relationship between the focus offset and the reproduction signal amplitude when the focus point is moved with the optimum focus point being zero. As is apparent from FIG. 3, it can be seen that the amplitude at the point of focus offset 0 is the maximum, and the amplitude increases and the amplitude decreases regardless of the polarity of the offset.

  A curve A in FIG. 4 shows the reciprocal of the reproduction signal amplitude of this characteristic. It is possible to correct the measurement error due to the focus offset by tabulating the reciprocal as shown by the curve A in FIG. 4 and multiplying it by the reproduction signal amplitude measured according to the focus offset amount. The horizontal axis in FIG. 4 represents the focus offset amount, but this may be considered to be the same as the magnitude of the focus error signal.

  For example, if the focus error that is the output of the focus addition circuit 5 is 0, the reproduction amplitude is multiplied by 1 as it is and stored in the controller 15, and when the focus error is +0.25 μm (point a in FIG. 4), The value is about 1.25, and the reproduction amplitude is multiplied by 1.25 and stored in the controller 15.

  The correction circuit 14 multiplies the reproduction signal amplitude output by the reproduction signal amplitude measurement circuit 13 at a predetermined cycle by a table value corresponding to the focus error value at that time, and outputs the result to the controller 15. For example, if there are 4000 points of amplitude data within an amplitude capture period of 4 mS with a predetermined tracking offset, each of them is multiplied by a table value based on the focus offset at that time and accumulated in the controller 15.

  That is, even if the reproduction amplitude value accumulated by the controller 15 within a certain period does not show the original value temporarily due to the focus offset due to disturbance such as vibration, that is, the focus error signal of the focus error signal at that time. Since the amplitude value is corrected by the value, it is possible to minimize the influence of vibration or the like.

  In the present embodiment, the correction table is a fine table as shown by curve A in FIG. 4, but the correction table is divided into predetermined focus error ranges, and the correction values are the same as long as they are within that range. Alternatively, a stepped table may be used. FIG. 4B shows an example of this, and shows a case where the table is set step by step so that the average value in the range is used as the table value every 0.05 μm. In that case, the number of tables can be reduced, and the circuit can be simplified.

  Further, only a value of every 0.05 μm is provided, and the value between them may be obtained by linear approximation. Furthermore, the correction amount may be obtained by calculation without using the correction table by approximating the relationship between the magnitude of the error signal and the correction amount with a function.

  Furthermore, in the present embodiment, the correction table is a standard table. However, when the focus offset adjustment is performed in the same procedure as the tracking offset adjustment prior to the tracking offset adjustment, the horizontal axis is obtained from the nine accumulated data. Thus, a relationship similar to that in FIG. 3 can be measured, with focus offset and vertical axis representing reproduction amplitude. The reciprocal of the measurement data may be used as a correction table. In this case, since the optical disk 1 and the optical pickup unit 2 that are actually used are used, the accuracy of correction can be made more accurate.

  Also, in the pre-shipment adjustment process at the factory, the reproduction amplitude is measured by changing the offset using a standard disk, the reciprocal table value based on the value is stored in the EEPROM or the like, and the value is used. good. The relationship between the servo offset and the amplitude is more affected by the difference in the optical pickup unit than the effect by the difference in the disk. Therefore, a standard table is created by creating a reciprocal table for each optical pickup unit at the time of shipment from the factory. Compared with the method using the method, correction considering the difference of the optical pickup unit is possible, and more accurate correction can be performed.

  Furthermore, the focus error signal used in the correction circuit 14 is averaged over the same period as the reproduction signal amplitude measurement period (1 μs in the present embodiment) or a period during which the influence of disturbance such as vibration can be detected. May be. In that case, more accurate correction without the influence of noise or the like is possible.

  Further, in this embodiment, the reproduction signal amplitude is corrected according to the magnitude of the focus error signal during the tracking offset adjustment. However, the error signal that causes correction is not limited to the magnitude of the tracking error signal or the objective lens. The magnitude of the lens position signal, the magnitude of the spherical aberration error signal, etc. may be used, and any error signal may be used as long as the horizontal axis of the table or function related to the reproduction signal amplitude as shown in FIG.

  In this embodiment, the reproduction signal amplitude is used as a reproduction index as a signal quality evaluation means. However, any index that changes depending on the magnitude of the servo error signal, such as a jitter value or an error rate, may be used.

  Furthermore, the adjustment item is not limited to the tracking offset, and any adjustment is possible as long as the signal quality is adjusted as a reproduction index, such as various servo offsets, spherical aberration amount adjustment, reproduction power adjustment, and equalization filter adjustment. This spherical aberration amount adjustment, reproduction power adjustment, and equalization filter adjustment will be described in detail in another embodiment.

  In addition, the magnitude of the focus error signal is seen as an item for correcting the influence of disturbance, but at the same time, the magnitude of the tracking error signal may be observed and both corrections may be performed simultaneously. In that case, it is possible to minimize the influence of both the focus and tracking disturbances.

  Further, other correction items, for example, correction based on the lens position or the like may be performed simultaneously. Further, it is also possible to detect a change in the spherical aberration of the spot on the medium caused by a change in the thickness of the disc transmission substrate, and to correct the amplitude value of the reproduction signal based on the detected value of the spherical aberration.

  As described above, according to the present embodiment, even when the focus error instantaneously increases due to disturbance such as vibration during the tracking offset adjustment operation, the reproduction signal amplitude value corrected by the correction table is used. It is possible to minimize the influence of disturbance. In addition, since the adjustment is not performed again from the beginning due to vibration, the adjustment can be completed within a certain time. Further, since the index can be detected even under continuous vibration, the adjustment does not converge.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the first embodiment, the purpose is to suppress the influence of disturbance such as vibration on the focus at the time of tracking offset adjustment, but in this embodiment, the influence of disturbance on the focus at the time of focus offset adjustment is suppressed. The configuration and normal operation of the second embodiment are the same as those of the first embodiment.

  Next, a method for adjusting the optimum focus offset will be described with reference to the flowchart of FIG. As in the case of the tracking offset, the optimum focus offset adjustment is performed in a state where focus and tracking control are applied in the same manner as in the normal mode on an adjustment track on which a predetermined signal is recorded in advance. The controller 15 starts the adjustment operation in synchronization with the rotation synchronization signal from the spindle motor 16. First, an initial focus offset amount is given to the offset generation circuit 12 (S501). The tracking offset amount is 0 because it is before adjustment. Next, for a certain period, the output of the reproduction signal amplitude measurement circuit 13 is integrated into the memory in the controller 15 via the correction circuit 14 (S502, S503). Thereafter, the same processing as in the first embodiment is performed except that the focus offset is changed instead of the tracking offset.

  The controller 15 repeats the same operation while changing the offset amount, and ends the process at the ninth time (S504, S505). The amount of the focus offset is set to an appropriate range in consideration of the adjustment range, and is divided into eight equal parts from the minimum value to the maximum value around electrical zero. For example, it is set to every 0.1 μm from −0.4 μm to 0.4 μm.

  Next, the controller 15 detects the offset amount with the largest reproduction amplitude from the nine integrated data, sets it in the offset generation circuit 12, and ends the adjustment process (S506).

  Next, the correction circuit 14 will be described. The difference from the first embodiment is that, since the focus offset is adjusted, the optimum focus position is not yet known, and the zero point of the correction table and the optimum point are not present. Therefore, in the present embodiment, prior to the detailed measurement, a rough measurement is performed to measure the amplitude of the reproduction signal with two significantly different offset values of ± 0.15 μm, and the value and a standard table (or a standard table) The approximate zero point is obtained from the function), and the correction is made with that point as the zero point of the table. Although it takes extra time for rough adjustment, the accuracy of correction during vibration is improved. Subsequent processing is the same as in the first embodiment.

  As described above, even in this embodiment, even if the reproduction amplitude value integrated by the controller 15 within a certain period does not temporarily show an original value due to a focus offset due to disturbance such as vibration, the focus error signal at that time Since the amplitude value is corrected by the value, it is possible to minimize the influence of vibration.

  Also, in the pre-shipment adjustment process at the factory, the offset is changed using a standard disk and the reproduction amplitude is measured. The optimum offset value based on the value is stored in an EEPROM or the like, and the value is stored in the zero point of the table. It may be used as.

  The optimum value of the focus offset is more influenced by the difference of the optical pickup unit than the effect of the difference of the disc. Therefore, by storing the optimum focus offset value at the time of shipment from the factory, 0 point is obtained by rough measurement. Even if the operation is omitted, accurate correction can be made and no extra time is required.

  Further, in the pre-shipment adjustment process at the factory, the reproduction amplitude may be measured by changing the offset using a standard disk, the reciprocal table value based on the value may be stored in the EEPROM or the like, and the value may be used. .

  The relationship between the servo offset and the amplitude is more affected by the difference of the optical pickup unit than the effect of the difference of the disk, so a standard table can be created by creating a reciprocal table for each optical pickup unit at the factory shipment. The correction can be performed in consideration of the difference between the optical pickups compared to the method used, and more accurate correction can be performed. Further, since the adjustment is not repeated from the beginning due to vibration, the adjustment can be completed within a certain time.

  Furthermore, in this embodiment, the reproduction signal amplitude is corrected according to the magnitude of the focus error signal during the focus offset adjustment. However, the present invention is not limited to this, and the offset amount to be adjusted and the error signal that causes the correction are track errors. It may be the magnitude of the signal, the magnitude of the lens position signal, or the like, and any error signal can be used as long as it has a table or function related to the reproduction signal amplitude.

  In addition, although the reproduction signal amplitude is used as a reproduction index as a means for evaluating the signal quality, any index that varies depending on the magnitude of the servo error signal such as a jitter value and an error rate may be used. In addition, the magnitude of the focus error signal is seen as an item for correcting the influence of disturbance, but at the same time, the magnitude of the tracking error signal may be observed and both corrections may be performed simultaneously. In that case, it is possible to minimize the influence of both the focus and tracking disturbances.

  Further, other correction items, for example, correction based on the lens position of the objective lens may be performed simultaneously.

  As described above, according to the present embodiment, during the focus offset adjustment operation, even if the focus error instantaneously increases due to disturbance such as vibration, the reproduction signal amplitude value corrected by the correction table is used. It is possible to minimize the influence of the disturbance. In addition, since the adjustment is not performed again from the beginning due to vibration, the adjustment can be completed within a certain time. Further, since the index can be detected even under continuous vibration, the adjustment does not converge.

(Third embodiment)
Next, a third embodiment of the present invention will be described. FIG. 6 is a block diagram showing the configuration of the present embodiment. In FIG. 6, the same parts as those in FIG. The difference from FIG. 1 is that a spherical aberration generator driver 17 is added. As a spherical aberration amount generator, for example, a spherical aberration is generated by moving a coupling lens provided between an objective lens and a semiconductor laser as described in JP-A-10-106010. Can be used.

  The spherical aberration generator driver 17 drives a stepping motor connected to a coupling lens (not shown) in the optical pickup unit 2 according to an instruction from the controller 15.

  Next, the adjustment of the spherical aberration amount of the present embodiment will be described with reference to the flowchart of FIG. Optimal spherical aberration amount adjustment is performed in a state where focus and tracking control are applied in the same manner as in the normal mode on an adjustment track on which a predetermined signal is recorded in advance, as in the first and second embodiments.

  The controller 15 starts the adjustment operation in synchronization with the rotation synchronization signal from the spindle 16. First, an instruction is given to the spherical aberration generator driver 17, and the position of the coupling lens is set to the initial position (S701). Next, during a certain period, the output of the reproduction signal amplitude measurement circuit 13 is integrated into the memory in the controller 15 via the correction circuit 14 (S702, S703). Thereafter, the controller 15 changes the instruction to the spherical aberration generator driver 17 by a predetermined amount, repeats the same operation, and ends at the ninth time (S704, S705).

  The indication amount to the spherical aberration generator driver 17 is set to an appropriate range in consideration of the adjustment range of the optical system, and is divided into eight equal parts from the minimum value to the maximum value around the optimum point in the design. Next, the controller 15 detects the spherical aberration position with the largest reproduction amplitude from the nine accumulated data, sets it to the spherical aberration generator driver 17, and ends the adjustment process (S706).

  The correction circuit 14 multiplies the reproduction signal amplitude output by the reproduction signal amplitude measurement circuit 13 at a predetermined period by a table value corresponding to the focus error value at that time, and outputs the result to the controller 15. The operation of the correction circuit 14 is the same as that in the first embodiment.

  Also in this embodiment, when the focus offset adjustment is performed prior to the spherical aberration amount adjustment, the relationship between the focus offset amount and the reproduction signal amplitude can be measured, so that the data may be used as a correction table. . In this case, since the optical disk and the optical pickup unit that are actually used are used, the correction accuracy can be made more accurate.

  Also, in the pre-shipment adjustment process at the factory, the reproduction amplitude is measured by changing the offset using a standard disk, the reciprocal table value based on the value is stored in the EEPROM or the like, and the value is used. good. In this case, since the relationship between the servo offset and the amplitude is more affected by the difference in the optical pickup than the effect due to the difference in the disk, the correction considering the difference in the optical pickup is more effective than the method using the standard table. This makes it possible to perform more accurate correction.

  In this embodiment, the magnitude of the focus error signal is viewed as an item for correcting the influence of disturbance. However, the magnitude of the tracking error signal may be observed at the same time, and both corrections may be performed simultaneously. In that case, it is possible to minimize the influence of both the focus and tracking disturbances.

  Further, other correction items, for example, correction based on the lens position of the objective lens may be performed simultaneously.

  As described above, according to the present embodiment, even when the focus error momentarily increases due to disturbance such as vibration during the spherical aberration amount adjustment operation, the reproduction signal amplitude value corrected by the correction table is used. It is possible to minimize the influence of disturbance. In addition, since the adjustment is not performed again from the beginning due to vibration, the adjustment can be completed within a certain time. Further, since the index can be detected even under continuous vibration, the adjustment does not converge.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. Although the configuration of the fourth embodiment is the same as that of FIG. 1, in this embodiment, the reproduction power adjustment will be described with reference to FIGS. Similar to the first embodiment, the reproduction power adjustment is performed in a state in which focus and tracking control are applied in the same manner as in the normal mode on an adjustment track on which a predetermined signal of the optical disk is recorded in advance.

  First, the controller 15 starts an adjustment operation in synchronization with the rotation synchronization signal from the spindle motor 16. That is, an instruction is given to a laser control circuit (not shown), and the power of the semiconductor laser in the optical pickup unit 2 is set to an initial value (S801 in FIG. 8). Next, during a certain period, the output of the reproduction signal amplitude measurement circuit 13 is integrated into the memory in the controller 15 via the correction circuit 14 (S802, S803). Thereafter, the controller 15 changes the instruction to the laser control circuit by a predetermined amount, repeats the same operation, and ends at the ninth time (S804, S805).

  The instruction amount to the laser control circuit is set to an appropriate range in consideration of the adjustment range, and is divided into eight equal parts from the minimum value to the maximum value around the optimum point in the design. The controller 15 detects the reproduction power with the largest reproduction amplitude from the nine integrated data, sets it in the laser control circuit, and ends the adjustment process (S806).

  The correction circuit 14 multiplies the reproduction signal amplitude output by the reproduction signal amplitude measurement circuit 13 at a predetermined period by a table value corresponding to the focus error value at that time, and outputs the result to the controller 15. The operation of the correction circuit 14 is the same as that in the first embodiment.

  Also in this embodiment, when the focus offset adjustment is performed prior to the reproduction power adjustment, the relationship between the focus offset amount and the reproduction signal amplitude can be measured, so that data may be used as a correction table. . In this case, since the optical disk and the optical pickup unit that are actually used are used, the correction accuracy can be made more accurate.

  Further, in the pre-shipment adjustment process at the factory, the reproduction amplitude may be measured by changing the offset using a standard disk, the reciprocal table value based on the value may be stored in an EEPROM or the like, and the value may be used. . In this case, the relationship between the servo offset and the amplitude is more influenced by the difference in the optical pickup than the effect due to the difference in the disk. Therefore, the difference in the optical pickup is considered rather than the method using the standard table. Correction can be performed, and more accurate correction can be performed.

  Furthermore, in the present embodiment, the magnitude of the focus error signal is viewed as an item for correcting the influence of disturbance, but at the same time, the magnitude of the tracking error signal may be observed and both corrections may be performed simultaneously. In that case, it is possible to minimize the influence of both the focus and tracking disturbances.

  Further, other correction items, for example, correction based on the lens position of the objective lens may be performed simultaneously.

  As described above, according to the present embodiment, even when the focus error instantaneously increases due to disturbances such as vibration during the reproduction power adjustment operation, the reproduction signal amplitude value corrected by the correction table is used. It is possible to minimize the influence of disturbance. In addition, since the adjustment is not performed again from the beginning due to vibration, the adjustment can be completed within a certain time. Further, since the index can be detected even under continuous vibration, the adjustment does not converge.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. FIG. 9 is a block diagram showing the configuration of the fifth embodiment, and FIG. 10 is a circuit diagram showing the configuration of the equalization filter. In FIG. 9, the same parts as those in FIG. In this embodiment, equalization filter adjustment will be described.

  In this embodiment, before and after the correction circuit 14 is different from that in FIG. 1, the reproduction signal is directly input to the correction circuit 14 without passing through the amplitude measurement circuit, and the corrected output is input to the equivalent filter 18. Further, the waveform equalized signal is input to a reproduction signal processing circuit (not shown) and also input to the reproduction signal amplitude measuring circuit 13, and the measured reproduction amplitude after the equalization filter is input to the controller 15.

  Similar to the first embodiment, the equalization filter adjustment is performed in a state where focus and tracking control are applied in the same manner as in the normal mode on an adjustment track on which a predetermined signal is recorded in advance.

  The equalization filter 18 is composed of an N-tap FIR type adaptive filter as shown in FIG. 10, and the reproduction signal x (n) has N−1 delay units 21 and N coefficient multipliers 22. The sum of the outputs of the multipliers (the output of the adder 23) is the filter output y (n). Reference numeral 24 denotes a coefficient update circuit, and 25 denotes an error signal generation circuit.

  The equalization filter adjustment operation is performed as follows. First, the reproduction signal x (n) that is the output of the correction circuit 14 is output as a filter output y (n) that has passed through an N-tap FIR filter, and the output is a Viterbi decoder (not shown) and Input to the error signal generation circuit 25. When the coefficient update operation of the equalization filter is permitted by the controller 15, the error signal generation circuit 25 calculates the difference between the ideal waveform and the filter output y (n), and applies the predetermined coefficient to the coefficient update circuit 24. .

  When reproducing a test pattern recorded in advance in a predetermined location on the optical disc 1 as in the present embodiment, the ideal waveform is known in advance, so if the ideal waveform is output and compared with the reproduced test pattern, Good.

  The coefficient update circuit 24 multiplies the output signal of the error signal generation circuit 25 and the input signal of each coefficient multiplier 22 and adds the result to the current coefficient to obtain the next coefficient.

  As this operation continues, the coefficients are optimized, the error approaches zero, and the equalization filter adjustment operation converges. At the time of convergence, the controller 15 prohibits the coefficient update operation (the output of the error signal generation circuit is 0 regardless of the input signal).

  During this adjustment, the correction circuit 14 multiplies the reproduction signal output from the detection circuit 3 by a table value corresponding to the value of the focus error at that time, and outputs the reproduction signal whose amplitude is corrected to the equalization filter 18. Thus, the equalization filter that is permitted to update the coefficient performs the updating operation based on the corrected reproduction signal.

  The operation of the correction circuit 14 is almost the same as that of the first embodiment. In the first embodiment, the amplitude of the reproduction signal measured at a predetermined period is multiplied by the value of the correction table. Then, the reproduction signal is multiplied by the correction table in real time.

  Also in this embodiment, when the focus offset adjustment is performed prior to the equalization filter adjustment, the relationship between the focus offset amount and the reproduction signal amplitude can be measured, so that data can be used as a correction table. good. In this case, since the optical disk and the optical pickup that are actually used are used, the correction accuracy can be made more accurate.

  Also, in the pre-shipment adjustment process at the factory, the reproduction amplitude is measured by changing the offset using a standard disk, the reciprocal table value based on the value is stored in the EEPROM or the like, and the value is used. good. In this case, since the relationship between the servo offset and the amplitude is more affected by the difference in the optical pickup than the effect due to the difference in the disk, the correction considering the difference in the optical pickup is more effective than the method using the standard table. This makes it possible to perform more accurate correction.

  Furthermore, in this embodiment, the magnitude of the focus error signal is viewed as an item for correcting the influence of disturbance, but the magnitude of the tracking error signal may be observed at the same time, and both corrections may be performed simultaneously. In that case, it is possible to minimize the influence of both the focus and tracking disturbances.

  Further, other correction items, for example, correction based on the lens position of the objective lens may be performed simultaneously.

  As described above, according to the present embodiment, during the equalizing filter adjustment operation, even if the focus error is instantaneously increased due to disturbance such as vibration, the reproduction signal corrected by the correction table is used. It is possible to minimize the influence of. In addition, since the adjustment is not performed again from the beginning by vibration, the adjustment can be completed within a certain time. Furthermore, since the index can be detected even under continuous vibration, the adjustment does not converge.

1 is a block diagram of a first embodiment of an optical information recording / reproducing apparatus according to the present invention. FIG. It is a flowchart which shows operation | movement of 1st Embodiment. It is a figure which shows the standard relationship of a focus offset and reproduction signal amplitude when a focus point is moved by making the optimal point of focus into 0. It is a figure which shows the reciprocal number of a focus offset and a reproduction signal amplitude. It is a flowchart explaining the 2nd Embodiment of this invention. It is a block diagram which shows the 3rd Embodiment of this invention. It is a flowchart which shows operation | movement of 3rd Embodiment. It is a flowchart explaining the 4th Embodiment of this invention. It is a block diagram which shows the 5th Embodiment of this invention. It is a circuit diagram which shows an equalization filter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical disk 2 Optical pick-up unit 3 Detection circuit 4 Focus error generation circuit 5 Offset addition circuit 6 Phase compensation circuit 7 Focus driver 8 Tracking error generation circuit 9 Offset addition circuit 10 Phase compensation circuit 11 Tracking driver 12 Offset generation circuit 13 Reproduction signal amplitude measurement Circuit 14 Correction circuit 15 Controller 16 Spindle motor 17 Spherical aberration generator driver 18 Equalization filter 21 Delay device 22 Coefficient multiplier 23 Adder 24 Coefficient update circuit 25 Error signal generation circuit

Claims (9)

In an optical information recording / reproducing apparatus for recording information or reproducing recorded information by irradiating the information recording medium with spot light and receiving reflected light from the recording medium, the reflected light from the recording medium is received. A light receiving element for detecting the servo error signal based on the light receiving signal of the light receiving element, a means for performing servo control based on the servo error signal, and a reproduction signal based on the light receiving signal of the light receiving element. Means for measuring a reproduction index indicating the quality of the reproduction signal, means for setting an offset of the servo control means based on the reproduction index measured by the measurement means, and correlation with the reproduction index An optical information recording / reproducing apparatus comprising: means for correcting the reproduction index according to the magnitude of a predetermined error signal. In an optical information recording / reproducing apparatus that records information or reproduces recorded information by irradiating the information recording medium with spot light and receiving reflected light from the recording medium, the reflected light from the recording medium is received. Information on the basis of the reproduction index measured by the measuring means An optical information recording / reproducing apparatus comprising: means for adjusting a parameter relating to recording or reproduction; and means for correcting the reproduction index in accordance with a magnitude of a predetermined error signal correlated with the reproduction index. 3. The optical information recording / reproducing apparatus according to claim 1, wherein the predetermined error signal is a focus error signal, a tracking error signal, a lens position signal of an objective lens, or a spherical aberration error signal. The optical information recording / reproducing apparatus according to claim 1, wherein the correction unit performs correction according to a correction table corresponding to the predetermined error signal. The optical information recording / reproducing apparatus according to claim 1, wherein the correction unit performs correction according to a correction function corresponding to the predetermined error signal. The optical information recording / reproducing apparatus according to claim 4, wherein the correction table is created based on a result of measuring a relationship with the predetermined error signal in advance. The optical information recording / reproducing apparatus according to claim 1, wherein the correction unit performs correction during measurement of the reproduction index. 3. The optical information recording / reproducing apparatus according to claim 1, wherein the reproduction index is an amplitude value of a reproduction signal, a jitter value of the reproduction signal, or an error rate of the reproduction signal. The optical information recording / reproducing apparatus according to claim 2, wherein the parameter adjustment unit adjusts spherical aberration, adjustment of reproduction power, or adjustment of an equalization filter.

Images