JP2009157976A - Optical disk drive and equalizer adjusting method of optical disk drive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further efficiently perform equalizer adjustment to an RF signal detected by a multiple division type photodetector in an optical pickup for a short time. <P>SOLUTION: An optical disk device 10A is provided, wherein a control part 11 repeats change of boosting amounts of three points and detection of jitter values of three points until a jitter value of a second point is made to be the minimum by shifting and setting again the gradual decrease or increase range of the boosting amounts of three points on a waveform equalizer 81A when the jitter value jt2 of the second point is not the minimum value in the jitter values jt1, jt2 and jt3 of the three points to the boosting amounts bt1, bt2 and bt3 of the three points measured by a jitter value measuring device 85, then approximating the jitter values of three points to the boosting amounts of the three points by a quadratic curve and obtains an optimal boosting amount bt-best where the jitter value of the quadratic curve is the minimum to set the optimal boosting amount on the waveform equalizer 81A. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  In the present invention, when an information signal recorded on the signal surface of an optical disc is reproduced by an optical pickup, a jitter value is obtained with respect to an RF signal obtained by receiving return light from the optical disc with a multi-division photo detector in the optical pickup. The present invention relates to an optical disc apparatus and an equalizer adjustment method for an optical disc apparatus that can perform the equalizer adjustment more efficiently and in a short time when performing the equalizer adjustment so as to be minimized.

  Generally, a disc shape such as a CD (Compact Disc), a DVD (Digital Versatile Disc) with a higher density than a CD, or a BD (Blu-ray Disc) with a higher density than a DVD. This optical disc records information signals such as music data, video data, and computer data on a track formed in a spiral or concentric pattern on the signal surface of the optical disc substrate, and when a recorded track is reproduced, It is often used because of its high-speed access.

  At this time, the optical disc can be roughly classified into a reproduction-only type and a recording / reproduction type.

  Here, the read-only optical disk is formed by forming a track spirally or concentrically with a concavo-convex pit row on the signal surface of a disk-shaped disk substrate by injection molding using a resin material. A signal surface is formed by forming a reflective film such as aluminum on the pit row.

  The read-only optical disc irradiates the signal surface with a reproduction laser beam spot emitted through an objective lens from an optical pickup provided so as to be movable in the radial direction of the optical disc in the optical disc device. The data is reproduced by receiving the return reflected light reflected from the light by the multi-divided photodetector.

  On the other hand, recording / reproducing type optical discs are formed in advance in a spiral or concentric pattern alternately with concave and convex grooves and lands on the signal surface of a disc-shaped disc substrate by injection molding using a resin material. A signal layer is formed by sequentially forming a recording layer and a reflective layer on the grooves and lands.

  The recording / reproducing type optical disc transmits an information signal to the recording layer of the signal surface by a recording laser beam spot emitted through an objective lens from an optical pickup provided so as to be movable in the radial direction of the optical disc in the optical disc apparatus. After recording, the recorded signal surface is reproduced with a reproducing laser beam spot whose laser power is smaller than that of the recording laser beam spot.

  Here, when the information signal recorded on the signal surface of each of the above-mentioned various optical discs is reproduced by an optical pickup provided in the optical disc apparatus, the return light from the optical disc is received by a multi-segment photo detector in the optical pickup. In order to compensate for the deterioration of the signal waveform of the RF signal among the obtained TE signal (tracking error signal), FE (focus error signal), and RF (Radio Frequency) signal, an equalizer adjustment is performed on the RF signal. Is well known.

  Generally, various frequency components are included in the above-described RF signal, and the higher the frequency, the lower the level. If the level remains low, the jitter of the RF signal deteriorates. In addition, when there is a frequency other than the necessary frequency component included in the RF signal, the jitter is also deteriorated.

  Therefore, boosting low frequency components in the RF signal or cutting components above or below a certain frequency in the RF signal to adjust the frequency characteristics of the RF signal so as to reduce jitter. It is called “adjustment”.

  The equalizer adjustment described above is performed by combining both the adjustment of the boost amount for the RF signal and the adjustment of the cutoff frequency for the RF signal.

  That is, the adjustment of the boost amount with respect to the RF signal is to determine the amount to increase the gain by boosting the RF signal around a certain frequency in the RF signal.

  On the other hand, the adjustment of the cut-off frequency with respect to the RF signal is to determine a frequency that is a point at which a component having a frequency width greater than or less than a certain frequency or a certain frequency width is reduced by 3 dB from the reference level.

  At this time, when the equalizer adjustment is performed on the RF signal in the optical disc apparatus, there is a technique in which both the adjustment of the boost amount for the RF signal and the adjustment of the cutoff frequency for the RF signal are combined (for example, patents). Reference 1 and Patent Document 2).

  First, in the optical disc apparatus and the reproducing method disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2001-23167) described below, the illustration thereof is omitted, and a simple description with reference to Patent Document 1 is as follows. Then, the cutoff frequency is set to α, the jitter amount at the three boost amounts is detected, the jitter amount is approximated by a quadratic function f of the boost amount, and the boost amount at the minimum point D is calculated. Thereafter, the cutoff frequency is set to α + β, the jitter amount at the three boost amounts is detected, the jitter amount is approximated by a quadratic curve f2 of the boost amount, and the boost amount at the minimum point H is calculated. Then, the boost amount is approximated by a straight line g passing through the points D and H as a function of the cutoff frequency, and a point I on the straight line g is calculated. Further, by changing the cutoff frequency of the low-pass filter and the boost amount of the equalizer, the jitter amount at points D, H, and I is detected, and the jitter amount is approximated by a quadratic function h of the cutoff frequency. By calculating the cut-off frequency and the boost amount at J, it is possible to accurately optimize the cut-off frequency of the low-pass filter and the boost amount of the equalizer by measuring the jitter amount at nine points. It is described that the adaptive equalization of the reproduction waveform can be performed by the measurement.

  Next, the equalizer adjustment method of the optical disk reproducing apparatus disclosed in the following Patent Document 2 (Japanese Patent Laid-Open No. 2002-8243) was previously proposed by the present applicant in order to perform the equalizer adjustment efficiently and in a short time. This will be omitted, and will be described briefly with reference to Patent Document 2. First, in step S1, the cutoff frequency is fixed, and the boost amount is sequentially increased from the first initial value. Differently, the boost amount with the least jitter is provisionally determined as the optimum value of the boost amount. Next, in step S2, the boost amount is fixed, the cutoff frequency is sequentially changed from the second initial value, and the cutoff frequency with the smallest jitter is provisionally determined as the optimum value of the cutoff frequency. Next, in step S3, the first initial value and the second initial value are averaged by measuring and averaging the optimum boost amount and cut-off frequency in each of the plurality of optical disks, thereby adjusting the equalizer. It is described that can be performed efficiently in a short time.

JP 2001-23167 A JP 2002-8243 A

  By the way, according to the optical disc apparatus and the reproduction method disclosed in Patent Document 1 described above, jitter is measured a total of nine times for a plurality of boost amounts and a plurality of cut-off frequencies, and the boost amount and cut-off frequency with the smallest jitter are measured. Therefore, there is a problem that the equalizer adjustment always takes a certain time, and the equalizer adjustment cannot be performed in a short time.

  Further, according to the equalizer adjustment method of the optical disk reproducing device disclosed in Patent Document 2, the equalizer adjustment time can be reduced as compared with Patent Document 1 described above. Since both the cutoff frequency is provisionally determined, the equalizer adjustment cannot be performed more efficiently and in a short time.

  Therefore, when the information signal recorded on the signal surface of the optical disk is reproduced by the optical pickup, the jitter value is minimum with respect to the RF signal obtained by receiving the return light from the optical disk with the multi-division photo detector in the optical pickup. Therefore, there is a demand for an optical disc apparatus and an equalizer adjustment method for the optical disc apparatus that can perform the equalizer adjustment more efficiently and in a short time.

The present invention has been made in view of the above-mentioned problems, and the first invention is that when the information signal recorded on the signal surface of the optical disc is reproduced by the optical pickup, the return light from the optical disc is stored in the optical pickup. In an optical disk apparatus that performs equalizer adjustment so that a jitter value is minimized with respect to an RF signal obtained by receiving light with a multi-divided photo detector,
A control unit having a memory in which boost values of three points having different values in order of magnitude are stored in advance, and a calculation unit and a determination unit for comparing and determining each jitter value with respect to the boost amount of the three points;
An equalizer circuit having a waveform equalizer in which the boost amount of the three points output from the memory is input only during equalizer adjustment, and a low-pass filter in which a fixed cutoff frequency is set;
A jitter value measuring device that measures each jitter value for each of the three boost amounts with respect to the output from the equalizer circuit;
When the second jitter value among the three jitter values with respect to the three boost values measured by the jitter value measuring device is not minimum, the control unit gradually decreases the three boost values. Alternatively, after the range of gradual increase is shifted and set again in the waveform equalizer, the change in the boost amount at the three points and the detection of the jitter value at the three points are repeated until the jitter value at the second point is minimized. Approximating the three-point jitter value with respect to the three-point boost amount by a quadratic curve, obtaining the optimum boost amount that minimizes the jitter value of the quadratic curve, and equalizing the optimum boost amount to the waveform An optical disc apparatus characterized in that the optical disc apparatus is set in a container.

According to a second aspect of the present invention, when an information signal recorded on the signal surface of an optical disc is reproduced by an optical pickup, the return light from the optical disc is received by a multi-division photo detector in the optical pickup. In an optical disc apparatus that performs equalizer adjustment so that a jitter value is minimized with respect to a signal,
A memory in which the appropriate boost amount is stored in advance so that the optimum boost amount is included within the set range of the three boost amounts having different values in order of magnitude, and each jitter value for the three boost amounts A control unit having a calculation unit and a determination unit for comparing and determining
An equalizer circuit having a waveform equalizer in which boost amounts of the three points output from the memory are input only during equalizer adjustment, and a low-pass filter in which a fixed cutoff frequency is set;
A jitter value measuring device that measures each jitter value for each of the three boost amounts with respect to the output from the equalizer circuit;
The control unit approximates a three-point jitter value with respect to the three boost amounts measured by the jitter value measuring device by a quadratic curve, and obtains an optimum boost amount that minimizes the jitter value of the quadratic curve. Then, the optical disk apparatus is characterized in that the optimum boost amount is set in the waveform equalizer.

According to a third aspect of the present invention, when an information signal recorded on the signal surface of an optical disc is reproduced by an optical pickup, the return light from the optical disc is received by a multi-division photo detector in the optical pickup. In an optical disc apparatus that performs equalizer adjustment so that a jitter value is minimized with respect to a signal,
A control unit including a memory that stores in advance three cut-off frequencies having different values in order of magnitude, and a calculation unit and a determination unit that compare and determine the jitter values for the three cut-off frequencies;
An equalizer circuit having a waveform equalizer in which a fixed amount of boost is set, and a low-pass filter to which the three cut-off frequencies output from the memory are input only during equalizer adjustment;
A jitter value measuring device that measures each jitter value for each of the three cutoff frequencies with respect to the output from the equalizer circuit;
When the second jitter value among the three jitter values corresponding to the three cut-off frequencies measured by the jitter value measuring device is not the minimum, the control unit performs the three-point cut-off frequency. The range of gradual decrease or increase is shifted and set again in the low-pass filter, and the change in the cutoff frequency at the three points and the detection of the jitter value at the three points are repeated until the jitter value at the second point is minimized. Later, three-point jitter values with respect to the three cut-off frequencies are approximated by a quadratic curve, an optimum cut-off frequency that minimizes the jitter value of the quadratic curve is obtained, and the optimum cut-off frequency is calculated. An optical disc apparatus characterized by being set in the low-pass filter.

According to a fourth aspect of the present invention, when an information signal recorded on the signal surface of an optical disc is reproduced by an optical pickup, the return light from the optical disc is received by a multi-segment photo detector in the optical pickup. In an optical disc apparatus that performs equalizer adjustment so that a jitter value is minimized with respect to a signal,
A memory in which the appropriate three cut-off frequencies are stored in advance so that the optimum cut-off frequency is included within the set range of the three cut-off frequencies having different values in order of magnitude; and the three cut-off frequencies. A control unit having a calculation unit and a determination unit for comparing and determining each jitter value for
An equalizer circuit having a waveform equalizer in which a fixed amount of boost is set, and a low-pass filter to which the three cut-off frequencies output from the memory are input only during equalizer adjustment;
A jitter value measuring device that measures each jitter value for each of the three boost amounts with respect to the output from the equalizer circuit;
The control unit approximates a three-point jitter value with respect to the three cut-off frequencies measured by the jitter value measuring device by a quadratic curve, and an optimum cut-off frequency that minimizes the jitter value of the quadratic curve. And the optimum cutoff frequency is set in the low-pass filter.

The fifth aspect of the invention provides a multi-division photo detector within the optical pickup for returning light from each optical disc when information signals recorded on the signal surfaces of a plurality of types of optical discs are selectively reproduced by the optical pickup. In the optical disc apparatus for performing the equalizer adjustment so that the jitter value is minimized with respect to each RF signal obtained by receiving light at
An optical disc type discriminating means for discriminating types of the plural types of optical discs;
A memory storing in advance three boost amounts having different values in order of magnitude and three cut-off frequencies having different values in order of magnitude, and each jitter value for the three boost amounts and the three cut-off frequencies. A control unit having a calculation unit and a determination unit for comparing and determining;
A first equalizer circuit having a waveform equalizer in which the boost amounts of the three points output from the memory are input only during equalizer adjustment, and a low-pass filter in which a fixed cutoff frequency is set;
A second equalizer circuit having a waveform equalizer in which a fixed amount of boost is set, and a low-pass filter to which the three cut-off frequencies output from the memory are input only during equalizer adjustment;
Each jitter value is measured for each of the three boost amounts with respect to the output from the first equalizer circuit, and each jitter value is measured for each of the three cutoff frequencies with respect to the output from the second equalizer circuit. Jitter value measuring instrument to measure the jitter value,
Switching means for selectively switching between the first equalizer circuit and the second equalizer circuit according to a determination result from the optical disc type determination means;
An optical disc apparatus characterized by comprising:

According to a sixth aspect of the present invention, when an information signal recorded on the signal surface of an optical disc is reproduced by an optical pickup, the return light from the optical disc is received by a multi-segment photo detector in the optical pickup. In an equalizer adjustment method for an optical disc apparatus that performs equalizer adjustment so that a jitter value is minimized with respect to a signal,
A control step for controlling the equalizer adjustment, including a memory that stores in advance three boost amounts having different values in order of magnitude, and a calculation unit and a determination unit that compare and determine the jitter values for the three boost amounts. When,
Equalizer adjustment for performing the equalizer adjustment by having a waveform equalizer in which the boost amounts of the three points output from the memory are input only at the time of equalizer adjustment, and a low-pass filter in which a fixed cutoff frequency is set Steps,
A jitter value measuring step of measuring each jitter value for each of the three boost amounts with respect to the output from the equalizer adjusting step,
In the control step, when the jitter value at the second point is not the minimum among the three jitter values with respect to the boost amount at the three points measured in the jitter value measuring step, the boost amount at the three points is gradually decreased. Alternatively, after the range of gradual increase is shifted and set again in the waveform equalizer, the change in the boost amount at the three points and the detection of the jitter value at the three points are repeated until the jitter value at the second point is minimized. Approximating the three-point jitter value with respect to the three-point boost amount by a quadratic curve, obtaining the optimum boost amount that minimizes the jitter value of the quadratic curve, and equalizing the optimum boost amount to the waveform An equalizer adjustment method for an optical disc apparatus, wherein the equalizer is set in a storage device.

According to a seventh aspect of the present invention, when an information signal recorded on the signal surface of an optical disc is reproduced by an optical pickup, the return light from the optical disc is received by a multi-segment photo detector in the optical pickup. In an equalizer adjustment method for an optical disc apparatus that performs equalizer adjustment so that a jitter value is minimized with respect to a signal,
A memory in which the appropriate boost amount is stored in advance so that the optimum boost amount is included within the set range of the three boost amounts having different values in order of magnitude, and each jitter value for the three boost amounts A control step for controlling the equalizer adjustment by having a calculation unit and a determination unit for comparing and determining
Equalizer adjustment for performing the equalizer adjustment by having a waveform equalizer in which the boost amounts of the three points output from the memory are input only at the time of equalizer adjustment, and a low-pass filter in which a fixed cutoff frequency is set Steps,
A jitter value measuring step of measuring each jitter value for each of the three boost amounts with respect to the output from the equalizer adjusting step,
The control step approximates a three-point jitter value with respect to the three boost amounts measured in the jitter value measurement step by a quadratic curve, and obtains an optimum boost amount that minimizes the jitter value of the quadratic curve. Then, the equalizer adjustment method for the optical disc apparatus is characterized in that the optimum boost amount is set in the waveform equalizer.

According to an eighth aspect of the present invention, when an information signal recorded on the signal surface of an optical disc is reproduced by an optical pickup, the return light from the optical disc is received by a multi-division photo detector in the optical pickup. In an equalizer adjustment method for an optical disc apparatus that performs equalizer adjustment so that a jitter value is minimized with respect to a signal,
The equalizer adjustment is controlled by having a memory that stores in advance three cut-off frequencies having different values in order of magnitude, and a calculation unit and a determination unit that compare and determine the jitter values for the three cut-off frequencies. Control steps;
Equalizer adjustment for performing the equalizer adjustment by having a waveform equalizer in which a fixed amount of boost is set and a low-pass filter to which the three cut-off frequencies output from the memory are input only at the time of equalizer adjustment Steps,
A jitter value measuring step for measuring each jitter value for each of the three cutoff frequencies with respect to the output from the equalizer adjusting step,
In the control step, when the jitter value at the second point is not the minimum among the three jitter values with respect to the three cut-off frequencies measured at the jitter value measuring step, the cut-off frequency at the three points The range of gradual decrease or increase is shifted and set again in the low-pass filter, and the change in the cutoff frequency at the three points and the detection of the jitter value at the three points are repeated until the jitter value at the second point is minimized. Later, three-point jitter values with respect to the three cut-off frequencies are approximated by a quadratic curve, an optimum cut-off frequency that minimizes the jitter value of the quadratic curve is obtained, and the optimum cut-off frequency is calculated. An equalizer adjustment method for an optical disc apparatus, wherein the equalizer is set to the low-pass filter.

According to a ninth aspect of the present invention, when an information signal recorded on the signal surface of an optical disc is reproduced by an optical pickup, the return light from the optical disc is received by a multi-division photo detector in the optical pickup. In an equalizer adjustment method for an optical disc apparatus that performs equalizer adjustment so that a jitter value is minimized with respect to a signal,
A memory in which the appropriate three cut-off frequencies are stored in advance so that the optimum cut-off frequency is included within the set range of the three cut-off frequencies having different values in order of magnitude; and the three cut-off frequencies. A control step of controlling the equalizer adjustment by having a calculation unit and a determination unit for comparing and determining each jitter value for
Equalizer adjustment for performing the equalizer adjustment by having a waveform equalizer in which a fixed amount of boost is set and a low-pass filter to which the three cut-off frequencies output from the memory are input only at the time of equalizer adjustment Steps,
A jitter value measuring step of measuring each jitter value for each of the three boost amounts with respect to the output from the equalizer adjusting step,
The control step approximates a three-point jitter value with respect to the three cut-off frequencies measured in the jitter value measurement step by a quadratic curve, and an optimum cut-off frequency that minimizes the jitter value of the quadratic curve. And the optimum cut-off frequency is set in the low-pass filter.

The tenth aspect of the invention provides a multi-division photo detector within the optical pickup that returns light from each optical disc when the information signal recorded on each signal surface of the plurality of types of optical discs is selectively reproduced by the optical pickup. In the equalizer adjustment method of the optical disc apparatus for performing the equalizer adjustment so that the jitter value is minimized for each RF signal obtained by receiving light at
An optical disc type discriminating step for discriminating types of the plural types of optical discs;
A memory storing in advance three boost amounts having different values in order of magnitude and three cut-off frequencies having different values in order of magnitude, and each jitter value for the three boost amounts and the three cut-off frequencies. A control step for controlling the equalizer adjustment by having a calculation unit and a determination unit for comparing and determining;
A first equalizer for performing the equalizer adjustment, comprising: a waveform equalizer in which the three boost amounts output from the memory are input only during equalizer adjustment; and a low-pass filter in which a fixed cutoff frequency is set. The equalizer adjustment step of
A second equalizer for performing the equalizer adjustment, comprising: a waveform equalizer in which a fixed amount of boost is set; and a low-pass filter to which the three cut-off frequencies output from the memory are input only during equalizer adjustment. The equalizer adjustment step of
Each jitter value is measured for each of the three boost amounts with respect to the output from the first equalizer adjustment step, and for each of the three cut-off frequencies with respect to the output from the second equalizer adjustment step. A jitter value measuring step for measuring each jitter value,
A switching step of selectively switching between the first equalizer adjustment step and the second equalizer adjustment step according to the determination result from the optical disc type determination step;
An equalizer adjusting method for an optical disc apparatus, comprising:

  According to the optical disc apparatus of the first invention and the equalizer adjustment method of the optical disc apparatus of the sixth invention, the equalizer circuit (equalizer adjustment step) is performed so that the jitter value is minimized with respect to the RF signal reproduced by the optical disc. ), The equalizer frequency (equalizer adjustment step) is set to a fixed cutoff frequency for the equalizer circuit (equalizer adjustment step) and the waveform equalizer in the equalizer circuit (equalizer adjustment step). When three boost amounts having different values in order are sequentially set, the control unit (control step) causes the three points of jitter to correspond to the three boost amounts measured by the jitter value measuring device (jitter value measurement step). If the jitter value at the second point is not the smallest of the values, shift the range of the gradual decrease or increase of the boost amount at the three points. After setting the shape equalizer again and repeating the change of the boost amount of 3 points and the detection of the jitter value of 3 points until the jitter value of the 2nd point is minimized, By approximating the jitter value with a quadratic curve, finding the optimal boost amount that minimizes the jitter value of this quadratic curve, and setting the optimal boost amount in the waveform equalizer, the patent document explained earlier Since the number of times of jitter value measurement can be reduced during the equalizer adjustment as compared to 1 and Patent Document 2, the equalizer adjustment can be performed more efficiently and in a short time.

  Further, according to the above-described optical disc apparatus of the second invention and the equalizer adjusting method of the optical disc apparatus of the seventh invention, the equalizer circuit (equalizer) is configured so that the jitter value is minimized with respect to the RF signal reproduced by the optical disc. When performing equalizer adjustment in the adjustment step), set a fixed cutoff frequency for the low-pass filter in the equalizer circuit (equalizer adjustment step), and then set the waveform equalizer in the equalizer circuit (equalizer adjustment step). Memory of the control unit (control step) so that there is a high possibility that the optimum boost amount is included in the set range of the three boost amounts having different values in order of magnitude. By preparing in advance, the control unit (control step) measured with a jitter value measuring device (jitter value measuring step) 3 Approximate the three jitter values for the boost amount with a quadratic curve, and find the optimum boost amount that minimizes the jitter value of this quadratic curve. An optimum boost amount that can be minimized can be determined, and the equalizer adjustment can be performed even more efficiently and in a short time.

  Further, according to the above-described optical disk device of the third invention and the equalizer adjustment method of the optical disk device of the eighth invention, the equalizer circuit (equalizer) so that the jitter value is minimized with respect to the RF signal reproduced by the optical disk. When performing equalizer adjustment in the adjustment step), set the fixed amount of boost to the waveform equalizer in the equalizer circuit (equalizer adjustment step), and then apply it to the low-pass filter in the equalizer circuit (equalizer adjustment step). On the other hand, when three cut-off frequencies having different values in order of magnitude are sequentially set, the control unit (control step) performs 3 for the three cut-off frequencies measured by the jitter value measuring device (jitter value measurement step). If the jitter value at the second point is not minimum among the jitter values at the point, the cutoff frequency at the three points is gradually decreased or gradually decreased. The low-pass filter is shifted again and the three-point cut-off is repeated after repeating the three-point cut-off frequency change and the three-point jitter value detection until the second-point jitter value is minimized. By approximating the three jitter values with respect to the frequency with a quadratic curve, obtaining the optimum cutoff frequency that minimizes the jitter value of this quadratic curve, and setting the optimum cutoff frequency in the low-pass filter, Since the number of times of jitter value measurement can be reduced during the equalizer adjustment as compared with Patent Document 1 and Patent Document 2 described above, the equalizer adjustment can be performed more efficiently and in a short time.

  Further, according to the above-described optical disk device of the fourth invention and the equalizer adjusting method of the above-described optical disk device of the ninth invention, the equalizer circuit (equalizer) is configured so that the jitter value is minimized with respect to the RF signal reproduced by the optical disk. When performing equalizer adjustment in the adjustment step), set the fixed amount of boost to the waveform equalizer in the equalizer circuit (equalizer adjustment step), and then apply it to the low-pass filter in the equalizer circuit (equalizer adjustment step). On the other hand, the control unit (control step) sets the appropriate three cut-off frequencies so that there is a high possibility that the optimum cut-off frequency is included in the set range of the three cut-off frequencies having different values in order of magnitude. By preparing in advance in the memory, the control unit (control step) becomes a jitter value measuring instrument (jitter value measuring step) Since the three jitter values for the three measured cutoff frequencies are approximated by a quadratic curve, the optimum cut-off frequency that minimizes the jitter value of this quadratic curve is obtained. In this measurement, an optimum cutoff frequency that minimizes the jitter value can be determined, and the equalizer adjustment can be performed even more efficiently and in a short time.

  In addition, according to the optical disk apparatus of the fifth invention and the equalizer adjusting method of the optical disk apparatus of the tenth invention, the jitter value is minimized for each RF signal selectively reproduced by a plurality of types of optical disks. When performing equalizer adjustment in the equalizer circuit (equalizer adjustment step), a first equalizer circuit (first equalizer adjustment step) that uses three boost amounts having different values in order of magnitude, and values in order of magnitude The second equalizer circuit (second equalizer adjustment step) using three cut-off frequencies with different values is switched according to the determination result output from the optical disk type determination means (optical disk type determination step). ) To selectively switch between three points, depending on the type of optical disc. The to-off frequency is prepared in advance in the memory of the control unit (control step), so that 3 for each of the first and second equalizer circuits (first and second equalizer adjustment steps) according to the type of the optical disk. It is possible to determine the optimum boost amount and cut-off frequency that minimizes the jitter value by measuring the jitter value of only a point, and it is possible to perform equalizer adjustment more efficiently and in a short time, and Various equalizer adjustments can be made according to the type.

  Hereinafter, an optical disc apparatus and an equalizer adjusting method for an optical disc apparatus according to an embodiment of the present invention will be described in detail in the order of Embodiment 1, Embodiment 2, and Embodiment 3 with reference to FIGS.

FIG. 1 is a configuration diagram showing the overall configuration of an optical disc apparatus according to a first embodiment of the present invention.
FIG. 2 is an enlarged view of the multi-divided photodetector provided in the optical pickup shown in FIG.

  As shown in FIG. 1, in the optical disc apparatus 10A according to the first embodiment, a control unit 11 for controlling the entire apparatus is provided using a microcomputer, and a control operation is performed in the control unit 11. ROM 11a preliminarily storing software for instructing, RAM 11b for temporarily storing a boost amount, a cut-off frequency (cutoff frequency) or a jitter value at the time of equalizer adjustment, which will be described later, an arithmetic unit 11c and a determination unit used at the time of equalizer adjustment 11d.

  In addition, in the optical disc apparatus 10A, as the optical disc D, for example, one of a BD (Blu-ray Disc) compliant with the BD standard and a DVD (Digital Versatile Disc) compliant with the DVD standard is the shaft of the spindle motor 12. It is selectively detachably mounted on the turntable 13 fixed to 12a, and is pressed on the turntable 13 by the disk clamper 14 from above and is firmly clamped, and operates according to a command from the control circuit 11. The rotation speed of the spindle motor 12 is CLV controlled via the first motor drive circuit 15 so that the optical disk D can be rotated together with the turntable 13 and the disk clamper 14.

  An optical pickup 20 is provided below the optical disc D so as to be movable in the radial direction of the optical disc D. The optical pickup 20 is configured such that the screwing portion 21a of the optical pickup housing 21 receives a command from the control unit 11. The optical disk D is provided so as to be linearly movable by being screwed to a lead screw 18 connected to a sled motor 17 that is rotationally driven by a second motor driving circuit 16 that operates in the above.

  The optical pickup 20 described above is configured to employ a system using a main beam and a pair of sub beams so as to be compatible with a read-only optical disc and a recordable / reproducible optical disc. In the case of supporting only an optical disc, a one-beam method is also possible.

  More specifically, in the optical pickup housing 21 of the optical pickup 20, the first laser light source 22a for BD that emits the first laser light L1 having a wavelength near 400 nm and the second laser light L2 near the wavelength 650 nm. A second laser light source 22b for DVD that emits light, a collimator lens 23 that converts the laser light from the first or second laser light source 22a or 22b into parallel light, and the laser light of the parallel light into the main beam 2 A diffractive element 24 for separating three sub-beams into three beams, a beam splitter 25 for separating laser light from the first or second laser light source 22a or 22b and return light from the optical disk D, and parallel laser light. A λ / 4 plate 26 that converts to circularly polarized light, and a main beam and two subs mounted in a lens holder 27 The objective lens 28 for both BD and DVD that condenses the first or second laser beam L1 or L2 of the three beams on the signal surface of the optical disc D and the objective lens 28 attached to the outer periphery of the lens holder 27. A tracking lens 29 and a focusing coil 30 that swing in a tracking direction and a focusing direction, and a return beam of three beams by a main beam and two sub beams reflected by the signal surface of the optical disc D are detected by a detection lens 31 and a cylindrical lens 32. And a multi-divided photodetector 33 that is detected via the sensor.

  Then, by selectively starting one of the first and second laser light sources 22a and 22b via the semiconductor laser driving circuit 19 and the switch SW1 according to a command from the control unit 11, a laser beam having a predetermined wavelength is emitted. The laser light is incident on the objective lens 28 via the collimator lens 23, the diffraction element 24, the beam splitter 25, and the λ / 4 plate 26, and is formed into three beams by the main beam and the two sub beams narrowed down by the objective lens 28. The first or second laser beam L1 or L2 reaches the signal surface of the optical disc D, the main beam is irradiated in a spot shape on one track in the signal surface, and the two sub beams are centered on one track. Irradiated in spots on both sides.

  At this time, when recording the information signal on the signal surface of the optical disc D, the semiconductor laser driving circuit 19 described above selects one of the first and second laser light sources 22a and 22b according to the recording signal RS applied thereto. One of them is driven to emit a recording laser beam having a recording power. On the other hand, when reproducing a recorded optical disk D, a reproducing laser beam having a power lower than the recording power is emitted. It is so driven.

  The objective lens 28 has a numerical aperture (NA) of about 0.85 with respect to BD and a numerical aperture (NA) of about 0.65 with respect to DVD. An opening limiting process is performed on the surface facing the four plates 26.

  Thereafter, the return light of the main beam and the return light of the two sub beams reflected by the metal reflection layer (not shown) formed on the signal surface of the optical disk D pass through the objective lens 28 and the λ / 4 plate 26. Then, the light is reflected by the beam splitter 25 and condensed on the multi-divided photodetector 33 via the detection lens 31 and the cylindrical lens 32.

  Here, as shown in an enlarged view in FIG. 2, the multi-divided photodetector 33 includes four light receiving areas A to D for detecting the return light of the main beam MB irradiated to one track on the optical disc D; Two light receiving areas E and F for detecting one sub beam SB1 irradiated to one track adjacent to one track, and two for detecting the other sub beam SB2 irradiated to the other track adjacent to one track The light receiving areas G and H are arranged on a single semiconductor substrate (not shown), and the areas A to H have the arrangement relation shown in the figure with respect to the track direction and the radial direction of the optical disc D. Incidentally, in the one-beam method corresponding to only the read-only optical disc, only the main beam MB irradiated to one track is used.

  Referring back to FIG. 1, a TE (tracking error) signal detection circuit 40 and a first A / D converter 41 are connected to the control unit 11 as a tracking control system after the multi-divided photodetector 33 in the optical pickup 20. In addition, an FE (focus error) signal detection circuit 50 and a second A / D converter 51 as a focus control system are connected to the control unit 11, and further, an RF signal detection circuit downstream from the multi-division type photodetector 33. 60 is provided.

Here, the TE signal detection circuit 40 detects a tracking error signal TE for controlling the objective lens 28 in the tracking direction with respect to the optical disc D. The tracking error signal TE is a well-known DPP (Differential Push). The detection signals received in the respective light receiving areas A to H in the multi-divided photodetector 33 shown in FIG. 2 by the Pull method are calculated based on the following equation 1.
[Equation 1]
TE = {(A + D)-(B + C)} + {(E−F) + (G−H)} (Formula 1).

  The analog tracking error signal TE detected by the TE signal detection circuit 40 is converted into a digital tracking error signal TE by the first A / D converter 41 and input to the control unit 11. A tracking control drive signal TD is generated based on the tracking error signal TE, and this tracking control drive signal TD is applied to the tracking coil 29 via the first D / A converter 42 and the TD DRIVE (tracking drive) circuit 43. Thus, the objective lens 28 can perform tracking control with respect to the optical disc D.

Next, the above-described FE signal detection circuit 50 detects a focus error signal FE for controlling the objective lens 28 in the focus direction with respect to the optical disc D. The focus error signal FE is a known astigmatism method. Thus, calculation processing is performed on each detection signal received by each of the light receiving areas A to D in the multi-divided photodetector 33 shown in FIG.
[Equation 2]
FE = (A + C)-(B + D) (Formula 2).

  Then, the analog focus error signal FE detected by the FE signal detection circuit 50 is converted into a digital focus error signal FE by the second A / D converter 51 and input to the control unit 11. A focus control drive signal FD is generated based on the focus error signal FE, and this focus control drive signal FD is applied to the focus coil 30 via the second DA converter 52 and the FD DRIVE (focus drive) circuit 53. The objective lens 28 can control the focus with respect to the optical disc D.

Next, in the above-described RF signal detection circuit 60, a data signal RF (hereinafter referred to as an RF signal) based on video data or audio data recorded on the signal surface of the optical disk D is shown in FIG. Addition calculation processing is performed on the detection signals received by the light receiving areas A to D in the photodetector 33 based on the following Expression 3.
[Equation 3]
RF = A + B + C + D (Formula 4).

  Further, in each subsequent stage of the FE signal detection circuit 50 and the RF signal detection circuit 60, an optical disk type determination circuit 70 for determining whether the optical disk D mounted on the turntable 13 is a BD or a DVD. Is provided.

  In the optical disc type discrimination circuit 70 described above, the focus error signal FE output from the FE signal detection circuit 50 and the RF signal output from the RF signal detection circuit 60 are input. For example, the first laser light L1 near 400 nm is first emitted from the first laser light source 22a for BD, which is the shortest wavelength, by using the technical idea disclosed in the publication No. 1, and the objective lens is applied to the optical disc D. A focus search is performed at 28, and the total reflected light amount by the RF signal is calculated to determine whether or not the optical disk D is mounted. If the mounted optical disk D is a BD, the BD determination signal Db is transmitted to the control unit 11. On the other hand, if it is a DVD, a DVD discrimination signal Dd is output to the control unit 11.

  The optical disc type discriminating circuit 70 is not limited to the above method, and any method can be used as long as it can discriminate between BD and DVD.

  Further, an equalizer circuit 80A, which is a main part of the first embodiment, is provided separately from the optical disc type determination circuit 70 at the subsequent stage of the RF signal detection circuit 60.

  The equalizer circuit 80A described above includes a waveform equalizer 81A and an LPF (low pass filter) 82A.

  Then, in the waveform equalizer 81A in the equalizer circuit 80A, three boost amounts bt1, bt2, bt3 having different values in order of magnitude stored in advance in the RAM 11b of the control unit 11 are inputted, and these 3 Using the point boost amounts bt1, bt2, and bt3, an optimum boost amount that minimizes the jitter value is obtained by an equalizer adjustment method that will be described later, and the RF signal is centered around a frequency in the RF signal by this optimum boost amount. Boost and increase the gain.

  At this time, with respect to the three boost amounts bt1, bt2, and bt3 having different values in the order stored in the RAM 11b of the control unit 11, a plurality of test optical discs conforming to the BD standard and the DVD standard are commercially available. It is preferable to determine from the plurality of optical discs for each type of optical disc, and three points from the RAM 11b of the control unit 11 according to the BD discrimination signal Db or DVD discrimination signal Dd output from the optical disc type discrimination circuit 70. The boost amounts bt1, bt2, and bt3 may be output sequentially.

  In the LPF 82A in the equalizer circuit 80A, a fixed value cutoff frequency cf0 stored in advance in the RAM 11b of the control unit 11 or a fixed value cutoff frequency cf0 stored in advance in the LPF 82A is set. With this fixed cut-off frequency cf0, a component having a frequency above, below or below a certain frequency in the RF signal is reduced by 3 dB from the reference level.

  Therefore, in the equalizer circuit 80A, which is a main part of the first embodiment, although the cutoff frequency for the RF signal is fixed, the boost amounts bt1, bt2, and bt3 having different values in order of the boost amount for the RF signal are set. Since the equalizer adjustment method for the optical disk apparatus according to the first embodiment of the present invention, which will be described later, is performed by obtaining an optimal boost amount that uses the smallest jitter value, the return light from the optical disk D is transmitted to the optical pickup 20. The equalizer adjustment can be performed more efficiently and in a short time with respect to the RF signal obtained by receiving the light with the multi-divided photo detector 33.

  Then, the output from the equalizer circuit 80A is binarized by a binarization circuit 83 provided in the latter stage, and the binarized data TD is branched into three, and a PLL (Phase Locked Loop) circuit 84 and a jitter value measurement Are input to the device 85 and the signal processing circuit 86, respectively.

  In the PLL circuit 84 described above, a clock CLK whose phase is synchronized with the binarized data TD output from the binarizing circuit 83 is generated, and this clock CLK is input to the jitter value measuring device 85.

  Further, in the jitter value measuring device 85 described above, a phase shift between the binarized data TD output from the binarizing circuit 83 and the clock CLK output from the PLL circuit 84 (hereinafter referred to as a jitter value). The jitter value jt for the RF signal is temporarily stored in the RAM 11b of the control unit 11.

  Further, the signal processing circuit 86 described above conforms to the standard of the optical disc D according to the type of the optical disc D detected by the optical disc type detection circuit 70 based on the binarized data TD output from the binarization circuit 83. The main data signal MD is obtained based on the corresponding predetermined format.

  In the optical disk apparatus 10A of the first embodiment described above, BD and DVD can be selectively mounted as a plurality of types of optical disks D. However, the present invention is not limited to this, so that a known CD can also be applied. A third laser light source (not shown) for CD that emits a third laser light having a wavelength near 780 nm may be provided. In the case of this CD, the numerical aperture of the objective lens 28 is about 0.45. As described above, the objective lens 28 may be subjected to aperture restriction processing.

  Here, the equalizer adjustment method of the optical disk apparatus of the first embodiment by the optical disk apparatus 10A of the first embodiment configured as described above will be described in combination with FIG. 1 described above and the new FIGS. .

FIG. 3 is a flowchart for explaining an equalizer adjustment method of the optical disc apparatus according to the first embodiment of the present invention.
FIG. 4 is a characteristic diagram showing the relationship between the boost amount and the jitter value in the equalizer adjustment method of the optical disc apparatus according to the first embodiment of the present invention.

  As shown in FIG. 3, when the equalizer adjustment of the first embodiment is started, first, in step S1, the waveform equalizer 81A in the equalizer circuit 80A is stored in advance in the RAM 11b of the control unit 11. An initial value bt1 of the first boost amount among the three boost amounts bt1, bt2, bt3 having different values in order of magnitude is input, and the initial value bt1 of the boost amount is set in the waveform equalizer 81A. .

  Next, in step S2, the output from the equalizer circuit 80A set to the initial value bt1 of the boost amount is binarized by the binarizing circuit 83, and the binarized data TD is converted into the PLL circuit 84, the jitter value measuring instrument 85, The jitter value measuring device 85 measures the first jitter value jt1 corresponding to the initial boost value bt1 and temporarily stores the first jitter value jt1 in the RAM 11b of the control unit 11. Memorize.

  Next, in step S3, a second boost amount bt2 having a value larger than the initial boost value bt1 is input from the RAM 11b of the control unit 11 to the waveform equalizer 81A in the equalizer circuit 80A.

  Next, in step S4, the second jitter value jt2 corresponding to the second boost amount bt2 is measured by the same operation as in step S2, and the second jitter value jt2 is measured by the controller 11. It is temporarily stored in the RAM 11b.

  Next, in step S5, the third boost amount bt3 having a value larger than the second boost amount bt2 is input from the RAM 11b of the control unit 11 to the waveform equalizer 81A in the equalizer circuit 80A.

  Next, in step S6, the third jitter value jt3 corresponding to the third boost amount bt3 is measured by the same operation as in step S2 and step 4, and the third jitter value jt3 is controlled. The data is temporarily stored in the RAM 11b of the unit 11.

  Next, in step S7, the magnitude relationship between the three jitter values jt1, jt2, and jt3 temporarily stored in the RAM 11b of the control unit 11 is determined by the calculation unit 11c and the determination unit 11d of the control unit 11, It is asked whether or not the first jitter value jt1 is the minimum. If the first jitter value jt1 is the smallest (if YES) as a result of the determination, the optimum boost amount is the three boost amounts. It is estimated that the value is smaller than the change range of bt1, bt2, and bt3, and in step S8, the initial value bt1 of the boost amount is set to the waveform equalizer 81A again with a value smaller than the initial value bt1 this time. Returning to S1, thereafter, the processing of measuring jitter values at three points from step S1 is repeated again.

  On the other hand, if the jitter value jt1 at the first point is not the minimum at step S7 (in the case of NO), whether or not the jitter value jt3 at the third point is the minimum is determined at step S9. As a result, when the jitter value jt1 at the third point is the smallest (in the case of YES), it is estimated that the optimum boost amount is larger than the change range of the three boost amounts bt1, bt2, bt3, In step S10, the initial value bt1 of the boost amount is set to the waveform equalizer 81A again at a value larger than the initial value bt1 this time, and the process returns to step S1. Thereafter, the three-point jitter value measurement process from step S1 Repeat again.

  In other words, in step S8 or step S10 described above, the second of the three jitter values jt1, jt2, and jt3 with respect to the three boost amounts bt1, bt2, and bt3 measured by the jitter value measuring device 85. When the jitter value jt2 is not minimum, the range of the three boost amounts bt1, bt2, bt3 is gradually shifted and set again in the waveform equalizer 81A.

  In the first embodiment, in step S8 or step S10 described above, the range of gradual increase of the three boost amounts bt1, bt2, bt3 is shifted and set again in the waveform equalizer 81A. Conversely, the range of gradual reduction of the three boost amounts bt1, bt2, bt3 may be shifted and set in the waveform equalizer 81A again.

  Next, in step S11, since the jitter value jt3 at the third point is not the minimum at step S9 (in the case of NO), the jitter value jt2 at the second point is the smallest in combination with step S7 and step S9. In other words, since it is estimated that the optimum set value is included in the change range of the three boost amounts bt1, bt2, bt3, the jitter values jt1, jt2 at the three boost amounts bt1, bt2, bt3 , Jt3 is approximated as a quadratic curve of the jitter value with respect to the boost amount as shown in FIG.

  Next, in step S12, a boost amount at the jitter value minimum point (vertex) of the quadratic curve is obtained by calculation, and this is set as an optimum boost amount bt-best.

  Next, in step S13, the optimum boost amount bt-best obtained in step S12 is set in the waveform equalizer 81A in the equalizer circuit 80A via the control unit 11, and the equalizer adjustment is terminated.

  As described above, according to the optical disk device and the equalizer adjustment method of the optical disk device according to the first embodiment of the present invention, the equalizer circuit 80A adjusts the equalizer so that the jitter value is minimized with respect to the RF signal reproduced from the optical disk D. Are set to a fixed cutoff frequency cf0 for the LPF 82A in the equalizer circuit 80A, and then the three boosts having different values in order of magnitude with respect to the waveform equalizer 81A in the equalizer circuit 80A. When the amounts bt1, bt2, and bt3 are sequentially set, the control unit 11 uses the three points of jitter values jt1, jt2, and jt3 with respect to the three points of boost amounts bt1, bt2, and bt3 measured by the jitter value measuring device 85. If the jitter value jt2 at the second point is not the minimum, the range of the gradual decrease or increase in the boost amounts bt1, bt2, bt3 at the three points is set. Then, the waveform equalizer 81A is set again, until the second jitter value jt2 is minimized, the three boost values bt1, bt2, bt3 are changed, and the three jitter values jt1, jt2, jt3 are detected. , The three-point jitter values jt1, jt2, and jt3 for the three boost amounts bt1, bt2, and bt3 are approximated by a quadratic curve, and the optimum boost amount bt that minimizes the jitter value of the quadratic curve is obtained. -Best is determined, and the optimum boost amount bt-best is set in the waveform equalizer 81A, so that the number of times of jitter value measurement can be reduced during the equalizer adjustment as compared with Patent Document 1 and Patent Document 2 described above. Therefore, the equalizer adjustment can be performed more efficiently and in a short time.

  In the equalizer adjusting method of the optical disc apparatus according to the first embodiment of the present invention described above, when the equalizer is adjusted by the equalizer circuit 80A so that the jitter value is minimized with respect to the RF signal reproduced by the optical disc D, the equalizer is adjusted. After setting a fixed cut-off frequency cf0 for the LPF 82A in the circuit 80A, the boost amounts bt1, bt2, bt3 at three points having different values in order of magnitude with respect to the waveform equalizer 81A in the equalizer circuit 80A By preparing the appropriate boost amounts bt1, bt2, bt3 in the RAM 11b of the control unit 11 in advance so that the possibility that the optimum boost amount bt-best is included in the set range is increased. Since step 8 and step 9 described above can be omitted, the control unit 11 is provided with three booths measured by the jitter value measuring device 85. Since the three points of jitter values jt1, jt2, and jt3 for the amounts bt1, bt2, and bt3 are approximated by a quadratic curve, the optimum boost amount bt-best that minimizes the jitter value of the quadratic curve is obtained. The optimum boost amount bt-best that minimizes the jitter value can be determined by measuring the jitter values jt1, jt2, and jt3 of only the points, and the equalizer adjustment can be performed even more efficiently and in a short time.

  FIG. 5 is a block diagram showing the overall configuration of the optical disc apparatus according to the second embodiment of the present invention.

  The optical disk apparatus 10B according to the second embodiment of the present invention shown in FIG. 5 has the same configuration as that of the optical disk apparatus 10A according to the first embodiment of the present invention described above except for a part thereof. The only difference is that the equalizer circuit 80A, which is the main part of the first embodiment, is replaced by the equalizer circuit 80B, which is the main part of the second embodiment. Only the equalizer circuit 80B, which is the main part of the second embodiment, will be described, although the same reference numerals are attached and detailed description is omitted.

  As shown in FIG. 5, in the optical disc apparatus 10B according to the second embodiment of the present invention, the equalizer circuit 80B, which is the main part of the second embodiment, is branched separately from the optical disc type discriminating circuit 70 after the RF signal detection circuit 60. Is provided.

  The equalizer circuit 80B described above includes a waveform equalizer 81B and an LPF 82B.

  Then, in the waveform equalizer 81B in the equalizer circuit 80B, the fixed value boost amount bt0 stored in the RAM 11b of the control unit 11 in advance or the fixed value boost amount bt0 stored in advance in the waveform equalizer 81B. Is set, and with this fixed boost amount bt0, the RF signal is boosted around the frequency in the RF signal to increase the gain.

  Further, the LPF 82B in the equalizer circuit 80B inputs three cut-off frequencies cf1, cf2, and cf3 having different values in order of magnitude stored in the RAM 11b of the control unit 11 in advance, and cuts these three points. An optimum cutoff frequency that minimizes the jitter value is obtained by an equalizer adjustment method described later using the off frequencies cf1, cf2, and cf3, and a frequency that is higher, lower, or lower than a frequency in the RF signal by the optimum cutoff frequency. The width component is reduced by 3 dB from the reference level.

  At this time, for the three cut-off frequencies cf1, cf2, and cf3 having different values in the order of magnitude stored in advance in the RAM 11b of the control unit 11, a plurality of test optical discs conforming to the BD standard and the DVD standard are commercially available. It is preferable to determine each of the plurality of optical discs for each type of optical disc, and three points from the RAM 11b of the control unit 11 according to the BD discrimination signal Db or DVD discrimination signal Dd output from the optical disc type discrimination circuit 70. The cut-off frequencies cf1, cf2, and cf3 may be sequentially output.

  Therefore, in the equalizer circuit 80B, which is a main part of the second embodiment, the boost amount for the RF signal is fixed, but the cutoff frequencies for the RF signal are three cut-off frequencies cf1, cf2, and cf3 having different values in order of magnitude. Is used to obtain the optimum cutoff frequency that minimizes the jitter value, and the equalizer adjustment method of the optical disk apparatus according to the second embodiment of the present invention, which will be described later, is performed. Therefore, the return light from the optical disk D is picked up by the optical pickup. The equalizer adjustment can be performed more efficiently and in a short time with respect to the RF signal obtained by receiving light by the multi-divided photo detector 33 in FIG.

  Then, the output from the equalizer circuit 80B is binarized by the binarization circuit 83 provided in the latter stage as in the first embodiment, and the binarized data TD is branched into three, and the jitter with the PLL circuit 84 The values are input to the value measuring device 85 and the signal processing circuit 86, respectively.

  Here, the equalizer adjustment method of the optical disk apparatus of the second embodiment by the optical disk apparatus 10B of the second embodiment configured as described above will be described in combination with FIG. 5 described above and the new FIG. 6 and FIG. .

FIG. 6 is a flowchart for explaining an equalizer adjustment method of the optical disc apparatus according to the second embodiment of the present invention.
FIG. 7 is a characteristic diagram showing the relationship between the boost amount and the jitter value in the equalizer adjustment method of the optical disc apparatus according to the second embodiment of the present invention.

  As shown in FIG. 6, when the equalizer adjustment according to the second embodiment is started, first, in step S21, values are stored in order of magnitude stored in advance in the RAM 11b of the control unit 11 with respect to the LPF 82B in the equalizer circuit 80B. The initial value cf1 of the first cut-off frequency among the three cut-off frequencies cf1, cf2, and cf3 having different values is input, and the initial value cf1 of the cut-off frequency is set in the LPF 82B.

  Next, in step S22, the output from the equalizer circuit 80B set to the initial value cf1 of the cutoff frequency is binarized by the binarizing circuit 83, and the binarized data TD is converted into the PLL circuit 84 and the jitter value measuring device 85. The jitter value measuring device 85 measures the first jitter value jt1 corresponding to the initial value cf1 of the cutoff frequency, and the first jitter value jt1 is stored in the RAM 11b of the control unit 11. Memorize temporarily.

  Next, in step S23, a second cutoff frequency cf2 having a value larger than the cutoff frequency initial value cf1 is input from the RAM 11b of the control unit 11 to the LPF 82B in the equalizer circuit 80B.

  Next, in step S24, the second jitter value jt2 corresponding to the second cutoff frequency cf2 is measured by the same operation as in step S22, and the second jitter value jt2 is measured by the control unit 11. Is temporarily stored in the RAM 11b.

  Next, in step S25, the third cutoff frequency cf3 having a value larger than the second cutoff frequency cf2 is input from the RAM 11b of the control unit 11 to the LPF 82B in the equalizer circuit 80B.

  Next, in step S26, the third jitter value jt3 corresponding to the third cutoff frequency cf3 is measured by the same operation as in steps S22 and 24, and the third jitter value jt3 is calculated. The data is temporarily stored in the RAM 11b of the control unit 11.

  Next, in step S27, the magnitude relationship between the three jitter values jt1, jt2, and jt3 temporarily stored in the RAM 11b of the control unit 11 is determined by the calculation unit 11c and the determination unit 11d of the control unit 11, It is asked whether or not the first jitter value jt1 is the minimum, and if the first jitter value jt1 is the smallest (in the case of YES) as a result of the determination, the optimum cut-off frequency is 3 cuts It is estimated that the value is smaller than the change range of the off frequencies cf1, cf2, and cf3, and in step S28, the initial value cf of the cutoff frequency is set again to the LPF 82B at a value smaller than the initial value cf1 this time, and step S21 is performed. Thereafter, the jitter value measurement process at three points is repeated again from step S21.

  On the other hand, if the jitter value jt1 at the first point is not the minimum at step S27 (in the case of NO), at step S29, it is determined whether or not the jitter value jt3 at the third point is the minimum. As a result, when the jitter value jt1 at the third point is the smallest (in the case of YES), it is estimated that the optimum cutoff frequency is larger than the change range of the three cutoff frequencies cf1, cf2, and cf3. In step S30, the initial value cf1 of the cutoff frequency is set again in the LPF 82B at a value larger than the initial value cf1 this time, and the process returns to step S21. Repeat again.

  In other words, in step S28 or step S30, the second of the three jitter values jt1, jt2, and jt3 for the three cut-off frequencies cf1, cf2, and cf3 measured by the jitter value measuring device 85. If the jitter value jt2 is not the minimum, the range of the gradual increase of the three cut-off frequencies cf1, cf2, and cf3 is shifted and set in the LPF 82B again.

  In the second embodiment, in step S28 or step S30 described above, the gradual increase ranges of the three cut-off frequencies cf1, cf2, and cf3 are shifted and set again in the LPF 82B. The range of the gradual decrease of the three cut-off frequencies cf1, cf2, and cf3 may be shifted and set again in the LPF 82B.

  Next, in step S31, since the jitter value jt3 of the third point is not the minimum (in the case of NO) in step S29, the jitter value jt2 of the second point is the smallest in combination of step S27 and step S29. In other words, since it is estimated that the optimum set value is included in the change range of the three cut-off frequencies cf1, cf2, and cf3, the jitter value jt1 at the three cut-off frequencies cf1, cf2, and cf3. , Jt2, and jt3 are approximated as a quadratic curve of the jitter value with respect to the cutoff frequency as shown in FIG.

  Next, in step S32, the cut-off frequency at the jitter value minimum point (vertex) of the above-mentioned quadratic curve is obtained by calculation, and this is set as the optimum cut-off frequency cf-best.

  Next, in step S33, the optimum cutoff frequency cf-best obtained in step S32 is set in the LPF 82B in the equalizer circuit 80B via the control unit 11, and the equalizer adjustment is terminated.

  As described above, according to the optical disk device and the equalizer adjusting method of the optical disk device according to the second embodiment of the present invention, the equalizer circuit 80B performs the equalizer adjustment so that the jitter value is minimized with respect to the RF signal reproduced from the optical disk D. Is set to a fixed boost amount bt0 for the waveform equalizer 81B in the equalizer circuit 80B, and then the three cut-off values differing in order of magnitude from the LPF 82B in the equalizer circuit 80B. When the frequencies cf1, cf2, and cf3 are sequentially set, the control unit 11 includes the three jitter values jt1, jt2, and jt3 corresponding to the three cut-off frequencies cf1, cf2, and cf3 measured by the jitter value measuring device 85. When the jitter value jt2 at the second point is not the minimum, the cutoff frequencies cf1, cf2, cf3 at the three points are gradually decreased or The range of increase is shifted and set again in the LPF 82B, and the three cut-off frequencies cf1, cf2, and cf3 are changed and the three jitter values jt1, jt2, and jt3 are detected until the second jitter value jt2 is minimized. After repeating the above, the three-point jitter values jt1, jt2, and jt3 with respect to the three cut-off frequencies cf1, cf2, and cf3 are approximated by a quadratic curve, and an optimum cut that minimizes the jitter value of the quadratic curve is obtained. By obtaining the off-frequency cf-best and setting the optimum cut-off frequency cf-best in the LPF 82B, it is possible to reduce the number of times of jitter value measurement during the equalizer adjustment as compared with Patent Document 1 and Patent Document 2 described above. Therefore, the equalizer adjustment can be performed more efficiently and in a short time.

  In the equalizer adjusting method of the optical disc apparatus according to the second embodiment of the present invention described above, when the equalizer is adjusted by the equalizer circuit 80B so that the jitter value is minimized with respect to the RF signal reproduced by the optical disc D, the equalizer is adjusted. A fixed boost amount bt0 is set for the waveform equalizer 81B in the circuit 80B, and the three cutoff frequencies cf1, cf2, and cf3 are different in order of magnitude from the LPF 82B in the equalizer circuit 80B. Appropriate cut-off frequencies cf1, cf2, and cf3 are prepared in the RAM 11b of the control unit 11 in advance so that there is a high possibility that the optimum cut-off frequency cf-best is included in the set range. Thus, since the above-described step 28 and step 29 can be omitted, the control unit 11 measures with the jitter value measuring device 85. Further, the three-point jitter values jt1, jt2, and jt3 with respect to the three cut-off frequencies cf1, cf2, and cf3 are approximated by a quadratic curve, and the optimum cut-off frequency cf-best at which the jitter value of the quadratic curve is minimized. Therefore, the optimum cut-off frequency cf-best that minimizes the jitter value can be determined by measuring the jitter values jt1, jt2, and jt3 of only three points, and the equalizer adjustment can be performed even more efficiently. It can be done in a short time.

  FIG. 8 is a block diagram showing the overall configuration of the optical disc apparatus according to the third embodiment of the present invention.

  The optical disc apparatus 10C according to the third embodiment of the present invention shown in FIG. 8 includes an equalizer circuit 80A that is a main part of the optical disc apparatus 10A according to the first embodiment of the present invention described above and the above-described present invention. This embodiment differs from the first and second embodiments only in that both are provided with an equalizer circuit 80B that is a main part of the optical disc apparatus 10B according to the second embodiment. For convenience of explanation, the components shown above are used here. Only the equalizer circuits 80A and 80B, which are the main parts of the third embodiment, will be described, although the same reference numerals are used for the same and detailed description is omitted.

  As shown in FIG. 8, even in the optical disc apparatus 10C according to the third embodiment of the present invention, the equalizer circuits 80A and 80B, which are the main parts of the third embodiment, are different from the optical disc type discrimination circuit 70 in the subsequent stage of the RF signal detection circuit 60. Separately provided.

  At this time, the equalizer circuit 80A is configured by the waveform equalizer 81A and the LPF 82A, as in the first embodiment, and the waveform equalizer 81A is stored in advance in the RAM 11b of the control unit 11. Three points of boost amounts bt1, bt2, bt3 having different values in order of magnitude are inputted, and an optimum boost amount with the smallest jitter value is obtained using these three points of boost amounts bt1, bt2, bt3. With the optimum boost amount, the RF signal is boosted around the frequency in the RF signal to increase the gain, and the LPF 82A cuts a fixed value stored in advance in the RAM 11b of the control unit 11. An off frequency cf0 is input, and the fixed cutoff frequency cf0 is greater than or less than a certain frequency in the RF signal or a certain frequency. The components of the width, and is adapted to 3dB reduced from the reference level.

  On the other hand, the equalizer circuit 80B is configured by a waveform equalizer 81B and an LPF 82B, as in the second embodiment. In the waveform equalizer 81B, a fixed value stored in advance in the RAM 11b of the control unit 11 is used. The value boost amount bt0 is input, and the RF signal is boosted around the frequency in the RF signal by this fixed value boost amount bt0 to increase the gain. In addition, in the LPF 82B, the control unit 11 Three cut-off frequencies cf1, cf2, and cf3 having different values in order of magnitude stored in advance in the RAM 11b are input, and the jitter value is highest using these three cut-off frequencies cf1, cf2, and cf3. Find the optimal cutoff frequency that will be small, and this optimal cutoff frequency will be above or below the frequency in the RF signal. The components of a certain frequency width, and is adapted to 3dB reduced from the reference level.

  Further, a switch SW2 is connected to the subsequent stage of the equalizer circuits 80A and 80B. The switch SW2 is connected to the equalizer circuit 80A and the equalizer according to the BD determination signal Db or the DVD determination signal Dd output from the optical disc type determination circuit 70. The circuit 80B is selectively switched.

  At this time, for example, the equalizer circuit 80A may be selected based on the BD determination signal Db for BD, and the equalizer circuit 80B may be selected based on the DVD determination signal Dd for DVD. In addition, the equalizer circuit 80B may be selected by the BD determination signal Db for BD, and the equalizer circuit 80A may be selected by the DVD determination signal Dd for DVD.

  Further, the outputs from the equalizer circuits 80A and 80B are selectively switched by the switch SW2, and then binarized by the binarization circuit 83 provided at the subsequent stage of the switch SW2, so that the binarized data TD is 3 The signal is branched into two and input to the PLL circuit 84, the jitter value measuring device 85, and the signal processing circuit 86, respectively.

  The equalizer adjusting method according to the third embodiment of the present invention is the same as the equalizer adjusting method according to the first embodiment according to the present invention described above with reference to FIGS. 3 and 4 and previously described with reference to FIGS. Since the switch SW2 is selectively switched according to the BD discrimination signal Db or DVD discrimination signal Dd output from the optical disc type discrimination circuit 70 in the equalizer adjustment method according to the second embodiment of the present invention described above. The detailed description is omitted.

  As described above, according to the optical disk device and the equalizer adjusting method of the optical disk device according to the third embodiment of the present invention, the equalizer circuits 80A and 80B can minimize the jitter value with respect to the RF signal reproduced from the optical disk D. When performing equalizer adjustment, an equalizer circuit 80A that uses three boost amounts bt1, bt2, and bt3 having different values in order of magnitude, and an equalizer that uses three cut-off frequencies cf1, cf2, and cf3 having different values in order of magnitude Since the circuit 80B is selectively switched by the switch SW2 in accordance with the BD discrimination signal Db or DVD discrimination signal Dd output from the optical disc type discrimination circuit 70, the boost amount bt1 at three points according to the type of the optical disc D , Bt2, bt3 and three cutoff frequencies cf1, cf2, cf3 in the control unit 11 By preparing each in advance, an optimum boost amount and cut-off frequency that minimize the jitter value by measuring only three jitter values for each equalizer circuit 80A and 80B depending on the type of the optical disc D can be obtained. Thus, the equalizer adjustment can be performed more efficiently and in a short time, and various equalizer adjustments can be performed according to the type of the optical disc D.

1 is a configuration diagram illustrating an overall configuration of an optical disc device according to a first embodiment of the present invention. FIG. 2 is an enlarged view of a multi-segment photo detector provided in the optical pickup shown in FIG. 1. It is a flowchart for demonstrating the equalizer adjustment method of the optical disk apparatus of Example 1 which concerns on this invention. In the equalizer adjustment method of the optical disk apparatus of Example 1 which concerns on this invention, it is a characteristic view which showed the relationship between a boost amount and a jitter value. It is the block diagram which showed the whole structure of the optical disk apparatus of Example 2 which concerns on this invention. It is a flowchart for demonstrating the equalizer adjustment method of the optical disk apparatus of Example 2 which concerns on this invention. In the equalizer adjustment method of the optical disk apparatus of Example 2 which concerns on this invention, it is a characteristic view which showed the relationship between a cutoff frequency and a jitter value. It is the block diagram which showed the whole structure of the optical disk apparatus of Example 3 which concerns on this invention.

Explanation of symbols

10A Optical disk device of Example 1,
10B Optical disk apparatus of Example 2,
10C Optical disk device of Example 3,
11 control unit, 11a ROM, 11b RAM, 11c calculation unit, 11d determination unit,
12 sun pindle motor, 12a shaft, 13 turntable,
14 disk clamper, 15 first motor drive circuit, 16 second motor drive circuit,
17 thread motor, 18 lead screw, 19 semiconductor laser drive circuit,
20 optical pickup, 21 optical pickup housing, 21a screwing part,
22a first laser light source, 22b second laser light source, 23 collimator lens,
24 diffraction element, 25 beam splitter, 26 λ / 4 plate, 27 lens holder,
28 objective lens, 29 tracking coil, 30 focus coil,
31 detection lens, 32 cylindrical lens, 33 multi-segment photo detector,
40 TE (tracking error) signal detection circuit,
41 1st A / D converter, 42 1st D / A converter,
43 TD DRIVE (tracking drive) circuit,
50 FE (focus error) signal detection circuit,
51 2nd A / D converter, 52 2nd D / A converter,
53 FD DRIVE (focus drive) circuit,
60 RF signal detection circuit,
70 Optical disc type discrimination circuit,
80A, 80B equalizer circuit,
81A, 81B waveform equalizer, 82A, 82B LPF (low pass filter),
83 binarization circuit, 84 PLL (Phase Locked Loop) circuit,
85 Jitter value measuring instrument, 86 signal processing circuit, SW1, SW2 switch,
D optical disc, L1 first laser beam, L2 second laser beam,
TE tracking error signal, TD tracking control drive signal,
FE focus error signal, FD focus control drive signal,
Db BD discrimination signal, Dd DVD discrimination signal, RF data signal (RF signal),
TD binary data, CLK clock,
bto, bt1, bt2, bt3 boost amount,
cf0, cf1, cf2, cf3 cutoff frequency,
jt, jt1, jt2, jt3 Jitter values.

Claims (10)

When the information signal recorded on the signal surface of the optical disc is reproduced by an optical pickup, the jitter value is minimum with respect to the RF signal obtained by receiving the return light from the optical disc by the multi-division photo detector in the optical pickup. In an optical disc apparatus that performs equalizer adjustment so that
A control unit having a memory in which boost values of three points having different values in order of magnitude are stored in advance, and a calculation unit and a determination unit for comparing and determining each jitter value with respect to the boost amount of the three points;
An equalizer circuit having a waveform equalizer in which the boost amount of the three points output from the memory is input only during equalizer adjustment, and a low-pass filter in which a fixed cutoff frequency is set;
A jitter value measuring device that measures each jitter value for each of the three boost amounts with respect to the output from the equalizer circuit;
When the second jitter value among the three jitter values with respect to the three boost values measured by the jitter value measuring device is not minimum, the control unit gradually decreases the three boost values. Alternatively, after the range of gradual increase is shifted and set again in the waveform equalizer, the change in the boost amount at the three points and the detection of the jitter value at the three points are repeated until the jitter value at the second point is minimized. Approximating the three-point jitter value with respect to the three-point boost amount by a quadratic curve, obtaining the optimum boost amount that minimizes the jitter value of the quadratic curve, and equalizing the optimum boost amount to the waveform An optical disc apparatus characterized in that the optical disc apparatus is set in a container. When the information signal recorded on the signal surface of the optical disc is reproduced by an optical pickup, the jitter value is minimum with respect to the RF signal obtained by receiving the return light from the optical disc by the multi-division photo detector in the optical pickup. In an optical disc apparatus that performs equalizer adjustment so that
A memory in which the appropriate boost amount is stored in advance so that the optimum boost amount is included within the set range of the three boost amounts having different values in order of magnitude, and each jitter value for the three boost amounts A control unit having a calculation unit and a determination unit for comparing and determining
An equalizer circuit having a waveform equalizer in which the boost amount of the three points output from the memory is input only during equalizer adjustment, and a low-pass filter in which a fixed cutoff frequency is set;
A jitter value measuring device that measures each jitter value for each of the three boost amounts with respect to the output from the equalizer circuit;
The control unit approximates a three-point jitter value with respect to the three boost amounts measured by the jitter value measuring device by a quadratic curve, and obtains an optimum boost amount that minimizes the jitter value of the quadratic curve. The optimal boost amount is set in the waveform equalizer. When the information signal recorded on the signal surface of the optical disc is reproduced by an optical pickup, the jitter value is minimum with respect to the RF signal obtained by receiving the return light from the optical disc with the multi-division photo detector in the optical pickup. In an optical disc apparatus that performs equalizer adjustment so that
A control unit including a memory that stores in advance three cut-off frequencies having different values in order of magnitude, and a calculation unit and a determination unit that compare and determine the jitter values for the three cut-off frequencies;
An equalizer circuit having a waveform equalizer in which a fixed amount of boost is set, and a low-pass filter to which the three cut-off frequencies output from the memory are input only during equalizer adjustment;
A jitter value measuring device that measures each jitter value for each of the three cutoff frequencies with respect to the output from the equalizer circuit;
When the second jitter value among the three jitter values corresponding to the three cut-off frequencies measured by the jitter value measuring device is not the minimum, the control unit performs the three-point cut-off frequency. The range of gradual decrease or increase is shifted and set again in the low-pass filter, and the change in the cutoff frequency at the three points and the detection of the jitter value at the three points are repeated until the jitter value at the second point is minimized. Later, three-point jitter values with respect to the three cut-off frequencies are approximated by a quadratic curve, an optimum cut-off frequency that minimizes the jitter value of the quadratic curve is obtained, and the optimum cut-off frequency is calculated. An optical disc apparatus characterized by being set in the low-pass filter. When the information signal recorded on the signal surface of the optical disc is reproduced by an optical pickup, the jitter value is minimum with respect to the RF signal obtained by receiving the return light from the optical disc by the multi-division photo detector in the optical pickup. In an optical disc apparatus that performs equalizer adjustment so that
A memory in which the appropriate three cut-off frequencies are stored in advance so that the optimum cut-off frequency is included within the set range of the three cut-off frequencies having different values in order of magnitude; and the three cut-off frequencies. A control unit having a calculation unit and a determination unit for comparing and determining each jitter value for
An equalizer circuit having a waveform equalizer in which a fixed amount of boost is set, and a low-pass filter to which the three cut-off frequencies output from the memory are input only during equalizer adjustment;
A jitter value measuring device that measures each jitter value for each of the three boost amounts with respect to the output from the equalizer circuit;
The control unit approximates a three-point jitter value with respect to the three cut-off frequencies measured by the jitter value measuring device by a quadratic curve, and an optimum cut-off frequency that minimizes the jitter value of the quadratic curve. And the optimum cutoff frequency is set in the low-pass filter. Each RF obtained by receiving the return light from each optical disk with a multi-division photo detector in the optical pickup when the information signal recorded on each signal surface of the plural types of optical disks is selectively reproduced by the optical pickup In an optical disc apparatus that performs equalizer adjustment so that a jitter value is minimized with respect to a signal,
An optical disc type discriminating means for discriminating types of the plural types of optical discs;
A memory storing in advance three boost amounts having different values in order of magnitude and three cut-off frequencies having different values in order of magnitude, and each jitter value for the three boost amounts and the three cut-off frequencies. A control unit having a calculation unit and a determination unit for comparing and determining;
A first equalizer circuit having a waveform equalizer in which the boost amounts of the three points output from the memory are input only during equalizer adjustment, and a low-pass filter in which a fixed cutoff frequency is set;
A second equalizer circuit having a waveform equalizer in which a fixed amount of boost is set, and a low-pass filter to which the three cut-off frequencies output from the memory are input only during equalizer adjustment;
Each jitter value is measured for each of the three boost amounts with respect to the output from the first equalizer circuit, and each jitter value is measured for each of the three cutoff frequencies with respect to the output from the second equalizer circuit. Jitter value measuring instrument to measure the jitter value,
Switching means for selectively switching between the first equalizer circuit and the second equalizer circuit according to a determination result from the optical disc type determination means;
An optical disc apparatus comprising: When the information signal recorded on the signal surface of the optical disc is reproduced by an optical pickup, the jitter value is minimum with respect to the RF signal obtained by receiving the return light from the optical disc by the multi-division photo detector in the optical pickup. In an equalizer adjustment method for an optical disc apparatus that performs equalizer adjustment so that
A control step for controlling the equalizer adjustment, including a memory that stores in advance three boost amounts having different values in order of magnitude, and a calculation unit and a determination unit that compare and determine the jitter values for the three boost amounts. When,
Equalizer adjustment for performing the equalizer adjustment by having a waveform equalizer in which the boost amounts of the three points output from the memory are input only at the time of equalizer adjustment, and a low-pass filter in which a fixed cutoff frequency is set Steps,
A jitter value measuring step of measuring each jitter value for each of the three boost amounts with respect to the output from the equalizer adjusting step,
In the control step, when the jitter value at the second point is not the minimum among the three jitter values with respect to the boost amount at the three points measured in the jitter value measuring step, the boost amount at the three points is gradually decreased. Alternatively, after the range of gradual increase is shifted and set again in the waveform equalizer, the change in the boost amount at the three points and the detection of the jitter value at the three points are repeated until the jitter value at the second point is minimized. Approximating the three-point jitter value with respect to the three-point boost amount by a quadratic curve, obtaining the optimum boost amount that minimizes the jitter value of the quadratic curve, and equalizing the optimum boost amount to the waveform An equalizer adjustment method for an optical disc apparatus, characterized by comprising: When the information signal recorded on the signal surface of the optical disc is reproduced by an optical pickup, the jitter value is minimum with respect to the RF signal obtained by receiving the return light from the optical disc by the multi-division photo detector in the optical pickup. In an equalizer adjustment method for an optical disc apparatus that performs equalizer adjustment so that
A memory in which the appropriate boost amount is stored in advance so that the optimum boost amount is included within the set range of the three boost amounts having different values in order of magnitude, and each jitter value for the three boost amounts A control step for controlling the equalizer adjustment by having a calculation unit and a determination unit for comparing and determining
Equalizer adjustment for performing the equalizer adjustment by having a waveform equalizer in which the boost amount of the three points output from the memory is input only at the time of equalizer adjustment, and a low-pass filter in which a fixed cutoff frequency is set Steps,
A jitter value measuring step of measuring each jitter value for each of the three boost amounts with respect to the output from the equalizer adjusting step,
The control step approximates a three-point jitter value with respect to the three boost amounts measured in the jitter value measurement step by a quadratic curve, and obtains an optimum boost amount that minimizes the jitter value of the quadratic curve. The equalizer adjustment method for the optical disc apparatus, wherein the optimum boost amount is set in the waveform equalizer. When the information signal recorded on the signal surface of the optical disc is reproduced by an optical pickup, the jitter value is minimum with respect to the RF signal obtained by receiving the return light from the optical disc by the multi-division photo detector in the optical pickup. In an equalizer adjustment method for an optical disc apparatus that performs equalizer adjustment so that
The equalizer adjustment is controlled by having a memory that stores in advance three cut-off frequencies having different values in order of magnitude, and a calculation unit and a determination unit that compare and determine the jitter values for the three cut-off frequencies. Control steps;
Equalizer adjustment for performing the equalizer adjustment by having a waveform equalizer in which a fixed amount of boost is set and a low-pass filter to which the three cut-off frequencies output from the memory are input only at the time of equalizer adjustment Steps,
A jitter value measuring step for measuring each jitter value for each of the three cutoff frequencies with respect to the output from the equalizer adjusting step,
In the control step, when the jitter value at the second point is not the minimum among the three jitter values with respect to the three cut-off frequencies measured at the jitter value measuring step, the cut-off frequency at the three points The range of gradual decrease or increase is shifted and set again in the low-pass filter, and the change in the cutoff frequency at the three points and the detection of the jitter value at the three points are repeated until the jitter value at the second point is minimized. Later, three-point jitter values with respect to the three cut-off frequencies are approximated by a quadratic curve, an optimum cut-off frequency that minimizes the jitter value of the quadratic curve is obtained, and the optimum cut-off frequency is calculated. An equalizer adjustment method for an optical disc apparatus, wherein the equalizer is set in the low-pass filter. When the information signal recorded on the signal surface of the optical disc is reproduced by an optical pickup, the jitter value is minimum with respect to the RF signal obtained by receiving the return light from the optical disc by the multi-division photo detector in the optical pickup. In an equalizer adjustment method for an optical disc apparatus that performs equalizer adjustment so that
A memory in which the appropriate three cut-off frequencies are stored in advance so that the optimum cut-off frequency is included within the set range of the three cut-off frequencies having different values in order of magnitude; and the three cut-off frequencies. A control step of controlling the equalizer adjustment by having a calculation unit and a determination unit for comparing and determining each jitter value for
Equalizer adjustment for performing the equalizer adjustment by having a waveform equalizer in which a fixed amount of boost is set and a low-pass filter to which the three cut-off frequencies output from the memory are input only at the time of equalizer adjustment Steps,
A jitter value measuring step of measuring each jitter value for each of the three boost amounts with respect to the output from the equalizer adjusting step,
The control step approximates a three-point jitter value with respect to the three cut-off frequencies measured in the jitter value measurement step by a quadratic curve, and an optimum cut-off frequency that minimizes the jitter value of the quadratic curve. And setting the optimum cut-off frequency in the low-pass filter. Each RF obtained by receiving the return light from each optical disk with a multi-division photo detector in the optical pickup when the information signal recorded on each signal surface of the plural types of optical disks is selectively reproduced by the optical pickup In an equalizer adjustment method for an optical disc apparatus that performs equalizer adjustment so that a jitter value is minimized with respect to a signal,
An optical disc type discriminating step for discriminating types of the plural types of optical discs;
A memory storing in advance three boost amounts having different values in order of magnitude and three cut-off frequencies having different values in order of magnitude, and each jitter value for the three boost amounts and the three cut-off frequencies. A control step for controlling the equalizer adjustment by having a calculation unit and a determination unit for comparing and determining;
A first equalizer for performing the equalizer adjustment, comprising: a waveform equalizer in which the three boost amounts output from the memory are input only during equalizer adjustment; and a low-pass filter in which a fixed cutoff frequency is set. The equalizer adjustment step of
A second equalizer for performing the equalizer adjustment, comprising: a waveform equalizer in which a fixed amount of boost is set; and a low-pass filter to which the three cut-off frequencies output from the memory are input only during equalizer adjustment. The equalizer adjustment step of
Each jitter value is measured for each of the three boost amounts with respect to the output from the first equalizer adjustment step, and for each of the three cut-off frequencies with respect to the output from the second equalizer adjustment step. A jitter value measuring step for measuring each jitter value,
A switching step of selectively switching between the first equalizer adjustment step and the second equalizer adjustment step according to the determination result from the optical disc type determination step;
An equalizer adjustment method for an optical disc apparatus, comprising:

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