KR20010027859A - Track error detecting method of optical disc recording/repruducing device and apparatus therefor and sum signal generating apparatus - Google Patents

Abstract

PURPOSE: A device and a method for detecting a tracking error of an optical disk recording/reproducing unit, and a device for generating an addition signal, are provided to calculate phase differences of light receiving elements located in an identical line in a tangential direction from a 8-division optical detector, and to add the phase differences to obtain a tracking error signal, so that phase deterioration due to signal distortion can be prevented. CONSTITUTION: An 8-division light detector(502) has light receiving elements. The light receiving elements receive laser beam reflected in an optical disk. When applying the direction of an information row recorded in the optical disk to a tangential direction, and applying the direction rectangular with the information row to a radial direction, the light receiving elements are 2-divided equally in the tangential direction and 4-divided in the radial direction. Two inner light receiving elements are equally divided by having bandwidth smaller than the diameter of the received laser beam. The first phase comparator(504) compares phases of signals(A1,D1) generated in light receiving elements(a1,d1) existing in a downward direction to the outside and tangential direction from the 8-division light detector(502), to generate the first phase different signal. The second phase comparator(504) compares phases of signals(B1,C1) generated in light receiving elements(b1,c1) existing in an upward direction to the outside and tangential direction from the 8-division light detector(502), to generate the second phase different signal. The first adder(508) adds the phase difference signals generated in the first and the second phase comparators(504,506), to generate a tracking error signal.

Description

Tracking error detecting method of optical disc recording / repruducing device and apparatus therefor and sum signal generating apparatus}

The present invention relates to a tracking error detection method and apparatus, and more particularly, to a method and apparatus for improving a conventional differential phase detection tracking error (DPD TE) detection method and a sum signal generating apparatus.

Since DVD (Digital Versatile Disc) is a higher density narrow track than conventional CD (Compact Disc), the effect of cross-talk between tracks is greater and the gain of the tracking error signal is reduced. A detection method is required.

1 is a block diagram showing the configuration of the tracking error signal generating apparatus disclosed in the prior art (US4520469, Tokyo Shibaura, 85.5.28). The apparatus shown in FIG. 1 includes a quadrature photodetector 102 for receiving a laser beam reflected from a disk, a matrix circuit 104 for combining photoelectrically converted signals output from the four-segment photodetector 102, a matrix circuit ( High pass filters 106a and 106b for removing the low frequency components of the diagonal sum signals output from 104, amplifiers 108a and 108b, and phase comparators for generating a tracking error signal (TE) corresponding to the phase difference of the diagonal diagonal sum signals. 110.

The apparatus shown in Fig. 1 is a combination of a first diagonal sum signal generated from light receiving elements placed on one diagonal in a track of a disc and a second diagonal sum signal generated from light receiving elements placed on the other diagonal. A tracking error signal corresponding to the phase difference is obtained.

However, the apparatus shown in FIG. 1 has a problem that crosstalk noise occurs in a disc of a high density narrow track such as a DVD.

2 is for conceptually showing the operation of the tracking error detection apparatus disclosed in the prior art (Hi 9-285102, Toshiba, 97.10.17). The apparatus shown in FIG. 2 includes an eight-segment photodetector 202 for receiving a laser beam reflected from the disk, and a block 204 for generating a tracking error signal using the received light signals provided by the eight-segment photodetector 202. Equipped.

The apparatus of H9-285102 basically uses the phase difference of the diagonal sum signal of the light receiving elements a1, b1, c1, d1 located outside the eight-segment photodetector 202, as an example shown in FIG. As described above, a method of adding diagonal difference signals of light receiving elements a2, b2, c2, and d2 located in the inside at a predetermined ratio is used.

Here, the eight-segment photodetector 202 is for separating the zeroth order and ± first order beams of the laser beam reflected from the disk, and is composed of inner light receiving elements and outer light receiving elements, and the inner light receiving elements of the laser beam Corresponding to the 0th order beam and the overlapping region of the 0th order beam and the ± 1st order beam, the outer light receiving elements correspond to the region excluding the overlapping region of the 0th order beam and the ± 1st order beam in the ± first order beam region of the laser beam. That is, the zeroth order beam of the laser beam is detected by the inner light receiving elements, and the ± first order beam of the laser beam is detected by the outer light receiving elements.

The reason for using such an eight-segment light-receiving element is that the offset due to the shift of the lens can be eliminated by obtaining the phase difference of the diagonal sum signal generated from the outside and the inside.

Although the apparatus shown in FIG. 2 can expect the effect of reducing crosstalk noise, it does not contribute to the problem of gain reduction of the tracking error signal generated in the narrow track. In addition, the phase offset between the sum signals due to the pit depth, which may be caused by using the sum signal in the diagonal direction, becomes a problem, and may cause an offset of the tracking error signal when a lens shift occurs. There is also.

Figure 3 shows another tracking error detection method according to the prior art. While the conventional tracking error detection method finds a sum signal in a diagonal direction and detects a phase difference of the obtained sum signal, the conventional tracking error detection method shown in FIG. 3 uses the same line in the tangential direction in a quadrature photodetector. It is characterized in that the method for obtaining the phase difference between the light receiving elements located at and summing the obtained phase differences. This has the advantage of preventing phase degradation due to signal distortion that may be caused by summing signals in the diagonal direction. In particular, when the pit depth is different for each disc, the signal distortion of the diagonal sum signal is known to be very severe.

In FIG. 3, reference numeral 302 denotes a quadrant photodetector as shown in FIG.

The method shown in FIG. 3 is based on the photoreceptors located on the same line in the tangential direction in the four-segment photodetector 302, that is, the lower photoreceptors a1, d1 or the upper photoreceptor of the four-segment photodetector 302. The phase difference signals are obtained by comparing the phases of the signals A1 and D1 or B1 and C1 generated in the elements b1 and c1, respectively, and the tracking error signal is obtained by adding the generated phase difference signals.

FIG. 4 is shown to schematically show a variant embodiment of the tracking error detection method shown in FIG. 3. The method shown by FIG. 4 uses the received signals B1 and C1 generated at the upper photoreceptors b1 and c1 of the four-segment photodetector 302 compared to that of FIG. It is characterized by.

The method shown in FIG. 4 delays the signals B1 and C1 generated at the upper photoreceptors of the quadrant photodetector 302 and the signals A1 and D1 generated at the lower photoreceptors a1 and d1. The phase difference signal is obtained by comparing the phases of D1) and the lower delayed signals B11 and C11, respectively, and the tracking error signal is obtained by adding the generated phase difference signal.

This is to prevent the offset of the tracking error signal from causing lens shift due to the difference in the pit depth.

As the disk becomes higher density narrow track, the influence of cross-talk between tracks is greater, and the gain of the tracking error signal is reduced, which is more effective than the conventional tracking error signal detection method shown in FIGS. There is a need for a tracking error signal detection method.

It is an object of the present invention to provide an improved tracking error detection method for a disc of high density narrow track, which is devised to meet the above requirements.

Another object of the present invention is to provide a tracking error detection apparatus suitable for the above method.

Another object of the present invention is to provide a sum signal detection apparatus for a disc of a high density narrow track.

1 is a block diagram showing an example of a conventional tracking error detection apparatus.

2 is a block diagram showing another example of a conventional tracking error detection apparatus.

Figure 3 shows another tracking error detection method according to the prior art.

FIG. 4 schematically shows a modified embodiment of the tracking error detection method shown in FIG. 3.

5 is a block diagram showing an embodiment of a tracking error detection apparatus according to the present invention.

6 is a block diagram showing another embodiment of the tracking error detection apparatus according to the present invention.

FIG. 7 is a block diagram illustrating a modified embodiment of the apparatus shown in FIG. 5.

8 is a block diagram showing another embodiment of the tracking error detection apparatus according to the present invention.

9 shows another embodiment of a tracking error detection apparatus according to the present invention.

10 is a block diagram showing another embodiment of a tracking error detection apparatus according to the present invention.

FIG. 11 shows a variant embodiment of the device shown in FIG. 10.

12 is a block diagram showing another embodiment of a tracking error detection apparatus according to the present invention.

13 shows a sum signal detection apparatus according to the present invention.

The tracking error detection method according to the present invention which achieves the above object receives a laser beam reflected from the optical disc, and when the direction of the information string recorded on the optical disc is the tangential direction and the direction perpendicular to the information string is the radial direction, On the diagonal of the 8-segment photodetector with equally divided in the tangential direction, divided into four in the radial direction, the inner two having light receiving elements equally divided in width smaller than the diameter of the received laser beam. In the method for obtaining a tracking error signal by the difference of signals generated in the light receiving elements located,

The phases of the light receiving signals A1 and D1, B1 and C1 generated by the light receiving elements a1 and d1, b1 and c1 located on the same line in the outward and tangential directions of the eight-segment photodetector are compared, respectively. To obtain the phase difference signals and add the phase difference signals to obtain a tracking error signal.

Tracking error detection apparatus according to the present invention to achieve the above another object

Hereinafter, the configuration and operation of the present invention will be described in detail with reference to the accompanying drawings.

The tracking error detection method according to the present invention is characterized by obtaining a tracking error signal using an 8-segment photodetector. As shown in Fig. 5, the eight-segment photodetector is divided into two equally divided into the tangential direction when the direction of the information string recorded on the optical disk is in the tangential direction and the direction perpendicular to the information string in the radial direction. In the direction, the light is divided into four parts, but the two inner parts have light receiving elements equally divided in a width smaller than the diameter of the received laser beam.

The tracking error detection method according to the present invention uses a tracking error signal by using the received light signals generated from the outer light receiving elements a1, b1, c1, d1 or the inner light receiving elements a2, b2, c2, d2. Occurs.

According to the first embodiment of the tracking error detecting method according to the present invention, the light receiving elements a1 and col are positioned in the same line in the tangential direction from the light receiving elements a1, b1, c1, d1 on the outside of the 8-segment photodetector. Phase difference signals are obtained by comparing the phases of the light reception signals A1 and D1, B1 and C1 generated in d1, b1 and c1, respectively, and the tracking error signal is obtained by adding the phase difference signals.

Here, the phase comparison may be performed after delaying the received signals B1 and C1 generated by the upper light receiving elements b1 and c1 for a predetermined time.

According to another embodiment of the tracking error detection method according to the present invention, the light receiving elements a2 and d2 are located in the same line in the tangential direction in the light receiving elements a2, b2, c2, and d2 inside the eight-segment photodetector. and compare the phases of the received light signals A2 and D2, B2 and C2 generated in b2 and c2, respectively, to obtain phase difference signals, and add the phase difference signals to obtain a tracking error signal.

Here, the phase comparison may be performed after delaying the received signals B2 and C2 generated by the upper light receiving elements b2 and c2 for a predetermined time.

In the tracking error detection method according to the present invention, if the period of the channel clock is T and the detected average phase difference time is Δt, the minimum value of Δt / T when the laser beam is 0.1 μm away from the center of the pit train recorded on the optical disc. Is preferably 0.5.

In addition, if the maximum value of the tracking error signal is T1 and the negative maximum value is T2, the absolute maximum value of (T1-T2) / T1 + T2) is preferably 0.2.

Figure 5 is a block diagram showing an embodiment of the tracking error detection apparatus according to the present invention shows an example applied to the outer light-receiving elements of the eight-segment photodetector.

The device shown in FIG. 5 is an eight-segment photodetector 502 that receives a laser beam reflected from the disk, an outer lower photoreceptors a1, d1 or upper photoreceptors b1, of the eight-segment photodetector 502. In the first and second phase comparators 504 and 506 and the phase comparators 504 and 506 which compare phases of the signals A1 and D1 or B1 and C1 generated in c1, respectively, to obtain a phase difference signal. And a first adder 508 for adding the generated phase difference signals to obtain a tracking error signal.

The device shown in FIG. 5 is characterized in that a phase difference of light receiving elements located on the same line in the tangential direction in the eight-segment photodetector 502 is taken and the obtained phase differences are summed. This has the advantage of preventing phase degradation due to signal distortion that may be caused by summing signals in the diagonal direction.

Although the apparatus shown in FIG. 5 is applied to the outer photoreceptors of the eight-segment photodetector, the basic technical idea may also apply to the four-segment photodetector.

Figure 6 is a block diagram showing another embodiment of the tracking error detection apparatus according to the present invention shows an example applied to the inner light-receiving elements of the eight-segment photodetector.

6 shows signals A2 and D2 or B2 and C2 generated from the lower photoreceptors a2 and d2 or the upper photoreceptors b2 and c2 inside the eight-segment photodetector 502. A second adder for obtaining a tracking error signal by adding phase difference signals generated by the third and fourth phase comparators 604 and 606 and the phase comparators 604 and 606 to obtain a phase difference signal by comparing the phases of 608).

The device shown in FIG. 6 is similar to the device shown in FIG. 5. That is, the device shown in FIG. 6 is the same as the device shown in FIG. 5 except that the light receiving elements located inside the eight-segment photodetector 602 are used.

FIG. 7 is a block diagram illustrating a modified embodiment of the apparatus illustrated in FIG. 5, which corresponds to a case in which the apparatus illustrated in FIG. 5 and the apparatus illustrated in FIG. 6 are combined. Therefore, the same reference numerals are assigned to performing the same operations as those shown in FIGS. 5 and 6.

The device shown in FIG. 7 is generated at the outer lower photoreceptors a1, d1 or the upper photoreceptors b1, c1 of the eight-segment photodetector 502 of FIG. 5 that receives the laser beam reflected from the disk. Phase difference signals generated in the first phase comparator and the second phase comparators 504 and 506 and the phase comparators 504 and 506 which compare phases of the signals A1 and D1 or B1 and C1 respectively to obtain a phase difference signal. A first adder 508, and an amplifier 510 to add.

On the other hand, the phases of the signals A2 and D2 or B2 and C2 generated in the lower photoreceptors a2 and d2 or the upper photoreceptors b2 and c2 inside the eight-segment photodetector 502 of FIG. 5. The second adder 608 and the first adder for adding the phase difference signals generated by the third and fourth phase comparators 604 and 606, the phase comparators 604 and 606 to obtain a phase difference signal, respectively. And a third adder 720 that adds the addition result of the 508 and the second adder 608 to generate a tracking error signal.

In the apparatus shown in FIG. 7, the output of the second adder 608 is amplified by an amplifier 710 having a constant gain k and then added to the output of the first adder 508.

8 is a block diagram showing another embodiment of the tracking error detection apparatus according to the present invention and corresponds to a modified embodiment of the apparatus shown in FIG. Therefore, the same reference numerals are assigned to performing the same operation as shown in FIG.

The apparatus shown in FIG. 8 divides an eight-segment photodetector into four quadrants, and adds signals generated from the outer and inner photoreceptors belonging to each quadrant to use the same as a four-segment photodetector. The amplification degree of the signal generated in the inner light receiving element belonging to each quadrant is different from that of the signal generated in the outer light receiving element.

The apparatus shown in FIG. 8 includes the eleventh amplifiers to the fourteenth amplifiers for amplifying the signals A2 to D2 generated in the inner light receiving elements a2 to d2 of the eight-segment photodetector 502 to a predetermined amplification degree k. An eleventh that adds the signals A1-D1 generated at the outer photoreceptors a1-d1 of the amplifiers 810-816, the eight-segment photodetector 502, and the signals generated at the amplifiers 810-816. The first phase comparator 504 and the adders 822 and 824, which compare phases of the signals provided by the adders to the twelfth adders 818 to 824 and the adders 818 and 820, to obtain a phase difference signal. A second phase comparator 806 for comparing the phases of the signals to obtain a phase difference signal, and a first adder 508 for adding the phase difference signals generated by the phase comparators 504 and 506 to obtain a tracking error signal.

FIG. 9 shows another embodiment of the tracking error detection apparatus according to the present invention, and shows another modified embodiment of the apparatus shown in FIG. Therefore, the same reference numerals are assigned to performing the same operation as the apparatus shown in FIG.

The device shown in FIG. 9 delays the signals B1 and C1 generated at the upper photoreceptors of the eight-segment photodetector 502 and the signals A1 and D1 generated at the lower photoreceptors a1 and d1. The phase difference signal is obtained by comparing the phases of D1) and the lower delayed signals B11 and C11, respectively, and the tracking error signal is obtained by adding the generated phase difference signal. This is to prevent the offset of the tracking error signal from causing lens shift due to the difference in the pit depth.

The apparatus shown in FIG. 9 includes a first delayer and a second delayer for delaying the signals B1 and C1 generated by the light receiving elements b1 and c1 among the signals generated by the eight-segment photodetector 502. Delayed in the first phase comparator 504 and the delayers 910 and 912 for obtaining a phase difference signal by comparing the signals A1 and D1 generated in the light receiving elements a1 and d1. A second phase comparator 506 for comparing the phases of the signals B11 and C11 to obtain a phase difference signal, and a first adder for adding a phase difference signal generated from the phase comparators 504 and 506 to obtain a tracking error signal. 508.

10 is a block diagram showing another embodiment of a tracking error detection apparatus according to the present invention. The device shown in FIG. 10 corresponds to the method shown in FIG. 1 applied to the device shown in FIG. 1 to delay the signal generated in the light receiving elements c1 and b1 to prevent the offset according to the pit depth. do.

The apparatus shown in FIG. 10 is a signal generator 31 which delays the signals B1 and C1 generated by the light receivers among the signals generated by the photodetector, and the 32nd delay units 1004 and 1006 and the light receivers ( 31st and 32nd adders 1008 and 1010 for adding signals A1 and D1 generated in a1 and d1 and signals C11 and B11 generated in delayers 1004 and 1006, respectively. 31st amplifier 1012 for amplifying the signal generated by the 31st adder 1008 to a predetermined amplification degree k2, and a signal generated by the 31st amplifier 1012 and a signal generated by the 32nd adder 1010 And a thirty-first phase comparator 1002 for comparing the phases of the signals to obtain a tracking error signal.

FIG. 11 shows a variant embodiment of the device shown in FIG. 10. Therefore, the same reference numerals are assigned to performing the same operation as shown in FIG.

The apparatus shown in FIG. 11 delays signals C1, C2, B1, and B2 generated from the upper light receiving elements c1, c2, b1, and b2 among signals generated by the eight-segment photodetector. To delay signals 1104 to 1107, signals A1, A2, D1, and D2 generated by the lower photoreceptors a1, a2, d1, and d2, and delayers 1104 to 1107. Amplifying the signals generated by the thirty first to thirty-fourth adders 1108 to 1111 and the thirty-third adder 1009, which respectively add the received signals C11, C22, B11, and B22, to a predetermined amplification degree k; The signal generated by the thirty-third amplifier 1016 and the thirty-third adder 1016, which adds the signal generated by the thirty-third amplifier 1014 and the thirty-second amplifier 1014 and the signal generated by the thirty-third adder 1008 A thirty-first amplifier 1012 for amplifying at a predetermined amplification degree k2, a thirty-third adder 1018 for adding a signal generated from the thirty-second adder 1010 and a signal generated from the thirty-fourth adder 1011, and 31 Foot from Amplifier (1012) Comparing the phase of the signal generated in a signal and the adder 36 (1018) to include a first phase comparator 31, 1002, obtaining a tracking error signal.

12 is a block diagram showing another embodiment of a tracking error detection apparatus according to the present invention. The apparatus shown in FIG. 12 includes phase comparators 1202 and 1204 and a forty-first adder 1206.

The forty-first phase comparator 1202 includes the sum signal A1 + C1 of the received signals generated at the outer and lower photodetectors a1 and c1 of the eight-segment photodetector and the outer and upper photodetectors b1. , detects a phase difference between the sum signal B1 + C1 of the received light signals generated in d1).

The 42-phase phase comparator 1204 has a sum signal A2 + C2 of the received signals generated from the light receiving elements a2 and c2 inside and the bottom of the 8-split photodetector and the light receiving elements b2 and d2 inside and the upper side. Detects the phase difference between the sum signal B2 + C2 of the received light signals generated by the < RTI ID = 0.0 >

The forty-one adder 1204 adds the phase difference signals generated by the forty-first phase comparator 1202 and the forty-second phase comparator 1204.

13 shows a sum signal detection apparatus according to the present invention. The device shown in FIG. 13 delays the signals C1, C2, B1, and B2 generated from the upper light receiving elements c1, c2, b1, and b2 among the signals generated by the eight-segment photodetector. In the signals A1, A2, D1, and D2 and the delays 1304 and 1307, which are generated from the first to the 54th delay units 1304 to 1307, the lower light receiving elements a1, a2, d1, and d2. Amplifying a signal generated by the 51st to 54th adders (1308 to 1311) and the 51st adder (1308) for adding the calculated signals C11, C22, B11, and B22, respectively, to a predetermined amplification degree k. The signal generated by the 53rd adder 1316 and the 53rd adder 1310 that adds the signal generated by the 32nd amplifier 1314 and the 51st amplifier 1314 and the signal generated by the 52nd adder 1309. A fifty-second amplifier 1318 that amplifies to a predetermined amplification degree k1, a fifty-four adder 1320 that adds a signal generated by the fifty-fourth amplifier 1311 and a signal generated by the fifty-second amplifier 1318, and a fifty-third Adder 1316 and 54th By adding the signal generated in the divider 1320 includes a first adder 55 (1322) for outputting a sum signal (SUM) of the reproduction signal

In the apparatus shown in FIG. 13, the amplification degree k of the 51st amplifier 1314 and the amplification degree k1 of the 52nd amplifier 1318 are

It is desirable to have a relationship where k + k1 = constant constant.

In other words, when k becomes larger, k1 becomes smaller, and when k becomes smaller, k1 becomes larger so that the sum signal maintains a constant level.

As described above, the tracking error detection method according to the present invention obtains the phase difference of the light receiving elements located on the same line in the tangential direction in the 8-segment photodetector, and adds the obtained phase differences to the tracking error signal to make the diagonal as in the prior art. There is an advantage in that it is possible to prevent phase degradation due to signal distortion that may be caused by summing signals in the direction.

Claims (23)

When the laser beam reflected from the optical disk is received and the direction of the information string recorded on the optical disk is in the tangential direction and the direction perpendicular to the information string in the radial direction, the optical beam is equally divided into two in the tangential direction and in the radial direction. Is divided into four, but the inner two are tracking error signals due to the difference in the signals generated from the light receiving elements located on the diagonal of the eight-segment photodetector having the light-receiving elements equally divided into a width smaller than the diameter of the received laser beam. In the method of obtaining The phases of the light receiving signals A1 and D1, B1 and C1 generated by the light receiving elements a1 and d1, b1 and c1 located on the same line in the outward and tangential directions of the eight-segment photodetector are compared, respectively. Obtaining phase difference signals, and adding the phase difference signals to obtain a tracking error signal. The method of claim 1, wherein the phase comparison is performed after delaying the light receiving signals B1 and C1 generated in the outer and upper light receiving elements b1 and c1 of the eight-segment photodetector for a predetermined time. Tracking error detection method. The minimum value of? T / T according to any one of claims 1 to 2, wherein the period of the channel clock is T and the detected average phase difference time is? T. Tracking error detection method, characterized in that 0.5. The absolute maximum value of (T1-T2) / T1 + T2) according to claim 1 or 2, wherein the maximum value of the tracking error signal is T1 and the maximum value of the negative value is T2. Tracking error detection method characterized in that. When the laser beam reflected from the optical disk is received and the direction of the information string recorded on the optical disk is in the tangential direction and the direction perpendicular to the information string in the radial direction, the optical beam is equally divided into two in the tangential direction and in the radial direction. Is divided into four, but the inner two are tracking error signals due to the difference in the signals generated from the light receiving elements located on the diagonal of the eight-segment photodetector having the light-receiving elements equally divided into a width smaller than the diameter of the received laser beam. In the method of obtaining The phases of the light receiving signals A2 and D2, B2 and C2 generated by the light receiving elements a2 and d2, b2 and c2 located on the same line in the inner and tangential directions of the eight-segment photodetector are compared, respectively. Obtaining a phase error signal and adding the phase difference signals to obtain a tracking error signal. The tracking according to claim 5, wherein the phase comparison is performed after delaying the received signals B2 and C2 generated in the inner and upper light receiving elements b2 and c2 of the eight-segment photodetector for a predetermined time. Error detection method. The minimum value of? T / T according to claim 5 to 6, wherein the period of the channel clock is T and the detected average phase difference time is? T. Tracking error detection method, characterized in that 0.5. The absolute maximum value of (T1-T2) / T1 + T2) according to claim 5 to 6, wherein if the maximum value of the positive of the tracking error signal is T1 and the maximum value of the negative is T2, the absolute maximum value of (T1-T2) / T1 + T2) is 0.2. Tracking error detection method characterized in that. The optical disk recording / reproducing apparatus receives the laser beam reflected from the optical disk, and when the direction of the information string recorded on the optical disk is in the radial direction and the direction perpendicular to the information string is in the radial direction, it is divided equally into the tangential direction. The signals generated from the photoreceptors located on the diagonal of the eight-segment photodetector having four light splitting elements divided into four in the radial direction but two inner portions are equally divided in width smaller than the diameter of the received laser beam. An apparatus for obtaining a tracking error signal by a difference, A first phase for generating a first phase difference signal by comparing the phases of the signals A1 and D1 generated from the light receiving elements a1 and d1 which exist in the outer and tangential directions in the eight split photodetector. Comparator; A second phase for generating a second phase difference signal by comparing phases of the signals B1 and C1 generated in the photoreceptors b1 and c1 which exist upward in the outer and tangential directions in the eight-segment photodetector Comparator; And 5. A tracking error detecting apparatus including a first adder configured to generate a tracking error signal by adding phase difference signals generated by the first phase comparators and the second phase comparators. FIG. 5. The method of claim 9, A first delay unit for delaying the signal (B1) generated from the light receiving element (b1) located above and in the tangential direction in the eight-segment photodetector for a predetermined time period and providing the second phase comparator to the second phase comparator; And Further comprising a second delay unit for delaying the signal (D1) generated from the light receiving element (d1) present in the outer and tangential direction in the eight-segment photodetector for a predetermined time to provide to the second phase comparator A tracking error detection device, characterized in that (Fig. 9). The method of claim 10, A third phase comparator for generating a third phase difference signal by comparing the phases of the signals A2 and D2 generated in the light receiving elements a2 and d2 in the inner and tangential directions in the eight-segment photodetector ; A fourth phase comparator for generating a fourth phase difference signal by comparing the phases of the signals B2 and C2 generated in the light receiving elements b2 and c2 present in the inner and tangential directions upwards in the eight-segment photodetector ; A second adder for adding phase difference signals generated in the third phase comparators and the fourth phase comparators; And And a third adder for generating a tracking error signal by adding phase difference signals generated by the first adder and the second adder. 12. The tracking error detection device according to claim 11, further comprising an amplifier interposed between the second adder and the third adder to amplify the output of the second adder by a constant gain k. The method of claim 11, A first delay unit for delaying the signal (B1) generated from the light receiving element (b1) located above and in the tangential direction in the eight-segment photodetector for a predetermined time period and providing the second phase comparator to the second phase comparator; And Further comprising a second delay unit for delaying the signal (D1) generated from the light receiving element (d1) present in the outer and tangential direction in the eight-segment photodetector for a predetermined time to provide to the second phase comparator Tracking error detection device, characterized in that. The method of claim 13, A third delay unit for delaying a signal (B2) generated from the light receiving element (b2) present in the inner and tangential directions upward in the eight-segment photodetector for a predetermined time period and providing the fourth phase comparator to the fourth phase comparator; And The eight-segment photodetector further includes a fourth delay unit for delaying the signal D2 generated from the light receiving element d2 existing in the upper and the tangential directions for a predetermined time and providing the fourth phase comparator to the fourth phase comparator. A tracking error detection device characterized by the above-mentioned. The method of claim 9, An eleventh adder for adding the signal A2 generated from the light receiving element a2 existing in the inner and tangential directions below the A1 signal to the first phase comparator; A twelfth adder which adds a signal D2 generated from the light receiving element d2 which is present in the inner and tangential directions in the eight split photodetector to the D1 signal and provides it to the first phase comparator; A thirteenth adder which adds a signal D2 generated from the light receiving element c2 which is present in the inner and tangential directions in the eight split photodetector to the C1 signal and provides it to the second phase comparator; And And a fourteenth adder added to the B1 signal and added to the second phase comparator by adding the signal B2 generated from the light receiving element b2 located upward in the inner and tangential directions. Tracking error detection device, characterized in that. The method of claim 15, And an eleventh to fourteenth amplifiers which amplify A2, D2, C2, and D2 to a predetermined amplification, respectively, in front of the eleventh to fourteenth adders. The optical disk recording / reproducing apparatus receives the laser beam reflected from the optical disk, and when the direction of the information string recorded on the optical disk is in the radial direction and the direction perpendicular to the information string is in the radial direction, it is divided equally into the tangential direction. In the radial direction, the light splitting is divided into four in the radial direction, and two inside are received downward in the outward and tangential directions in the eight split photodetector having light receiving elements equally divided into a width smaller than the diameter of the received laser beam. A first adder for adding the signals A1 and D1 generated from the elements a1 and d1, an amplifier for amplifying the signal output from the first adder with a predetermined amplification, the outer side of the eight-segment photodetector, and An adder for adding the signals B1 and C1 generated from the light receiving elements b1 and c1 present in the tangential direction, and signals provided from the first and second adders. A tracking error detecting device comprising an adder for detecting a phase difference of a signal and providing the same as a tracking error signal. A first delay unit delaying the C1 signal by a predetermined time and providing the first adder to the first adder; And And a second delay unit for delaying the B1 signal by a predetermined time and providing the second adder to the second adder. The method of claim 17, A third adder for adding signals A2 and D2 generated from the light receiving elements a2 and d2 which are present in the inner and tangential directions downwards in the eight-segment photodetector; A fourth adder for adding the signal generated by the first adder and the signal generated by the third adder to the amplifier; A fifth adder for adding signals B2 and C2 generated from the photoreceptors b2 and c2 located upward in the inward and tangential directions in the eight-segment photodetector, and the second adder and the fifth adder And a sixth adder for adding the signals provided in the second comparator to the phase comparator. The method of claim 18, A third delayer for delaying the C2 signal by a predetermined time and providing the third adder to the third adder; And And a fourth delayer for delaying the B2 signal by a predetermined time and providing the fifth adder to the fifth adder. The method of claim 19, And a second amplifier interposed between the third adder and the fourth adder. The optical disk recording / reproducing apparatus receives the laser beam reflected from the optical disk, and when the direction of the information string recorded on the optical disk is in the radial direction and the direction perpendicular to the information string is in the radial direction, it is divided equally into the tangential direction. The signals generated from the photoreceptors located on the diagonal of the eight-segment photodetector having four light splitting elements divided into four in the radial direction but two inner portions are equally divided in width smaller than the diameter of the received laser beam. An apparatus for obtaining a tracking error signal by a difference, The light received from the sum signal A1 + C1 of the received signals generated at the outer and lower light receiving elements a1 and c1 of the 8-segment photodetector and the outer and upper light receiving elements b1 and d1. A forty-first phase comparator for detecting a phase difference between the sum signal B1 + C1 of the signals; The sum signal A2 + C2 of the received signals generated at the light receiving elements a2 and c2 inside and below the 8-split photodetector and the received signals generated at the light receiving elements b2 and d2 inside and the upper side A 42nd phase comparator which detects a phase difference between the sum signal B2 + C2; And And a forty-one adder configured to add a phase difference signal generated by the forty-first phase comparator and the forty-second phase comparator. The optical disk recording / reproducing apparatus receives the laser beam reflected from the optical disk, and when the direction of the information string recorded on the optical disk is in the radial direction and the direction perpendicular to the information string is in the radial direction, it is divided equally into the tangential direction. A device for obtaining a sum signal, which is a reproduction signal, from an eight-segment photodetector having four divisions in the radial direction and two inner portions having light receiving elements equally divided into a width smaller than the diameter of the received laser beam. 51st to 54th delayers for delaying signals C1, C2, B1, and B2 generated from the upper light receiving elements c1, c2, b1, and b2 among the signals generated by the 8-split photodetector. field; A sum of the signals A1, A2, D1, and D2 generated by the lower light receiving elements a1, a2, d1, and d2 and the signals C11, C22, B11, and B22 generated by the delayers, respectively. 51 to 54 adders; A fifty-first amplifier amplifying the signal generated by the fifty-sixth adder with a predetermined amplification degree k; A fifty-third adder for adding the signal generated by the fifty-one amplifier and the signal generated by the fifty-second adder; A fifty-second amplifier amplifying the signal generated by the fifty-third adder with a predetermined amplification degree k1; A 54th adder for adding a signal generated by the 54th adder and a signal generated by the 52nd amplifier; And And a 55th adder configured to add signals generated by the 53rd and 54th adders. The amplification degree k of the 51st amplifier and the amplification degree k1 of the 52nd amplifier are A sum signal generating device having a relationship in which k + k1 = constant constant.