KR20010035635A - Tracking error signal detecting apparutus and method for detecting reading signal - Google Patents

Abstract

PURPOSE: An apparatus for detecting a tracking error signal and a method for detecting a playback signal are provided to detect tracking error signal with improved characteristic. CONSTITUTION: A photodetector receives light reflected/diffracted on a record media. A circuit part calculates a detecting signal of the photodetector and detects a tracking error signal. The photodetector is formed with four light receiving areas(30a:A1,A2)(30b:B1,B2)(30c:C1,C2)(30d:D1,D2), which are arranged roughly in parallel to a direction of radius of the record media and a direction of track intersection, respectively, in a form of 2x2 matrix form. The circuit part compares phases of receiving areas arranged in the same line and then detects the tracking error signal based on a differential phase signal. A pair of phase comparators compare phases of inputted signals. An adder adds the differencial phase signal from the pair of phase comparators.

Description

Tracking error signal detecting apparutus and method for detecting reading signal}

The present invention relates to a tracking error signal detection device and a reproduction signal detection method, and more particularly, to a tracking error signal detection device capable of further improving the accuracy of tracking error signal detection and a reproduction capable of greatly reducing crosstalk noise. The present invention relates to a signal detection method.

As a general method of detecting the amount of tracking error signal of a disk by receiving light reflected from the light source of the optical pickup device and reflecting from the disk, a tracking error signal (TES) is detected by differential phase detection (DPD). There is a way to detect it.

Conventional DPD tracking error signal detection apparatus, as shown in Figure 1, the photodetector 1, the matrix circuit (2), two high-pass filters (HPF1, HPF2), two pulse shaping circuit (pulse shaping circuit) 4 and 5 and a phase comparator 6.

The photodetector 1 is composed of four partition plates A, B, C, and D arranged in a 2 × 2 matrix so as to receive light reflected from a disk (not shown) and independently photoelectrically convert them.

The matrix circuit 2 receives the signals (a, b, c, d) detected by the four-split plates (A, B, C, D), respectively, and divides the divided plates (A, C) (B, The detection signals of D) are summed up, respectively. At this time, if the optical spot formed on the disc is out of the track center of the disc, a time delay or phase difference occurs between the sum signals a + c and b + d. Tracking error signal accuracy can be known.

The high pass filter HPF1 and HPF2 remove low frequency components included in the a + c and b + d signals output from the matrix circuit, respectively, and pass only the high frequency components.

The a + c and b + d signals that have passed through the high pass filter HPF1 and HPF2, respectively, are converted into pulse signals while passing through the pulse shaping circuits 4 and 5, respectively, and the phase comparator 6 The phases of the pulse signals are compared to output a tracking error signal TES '.

As described above, an apparatus for detecting a tracking error signal using a quad split photodetector by a DPD method is typically employed in a ROM (Read Only Memory) type disk drive to detect a degree of tracking error of a disk.

However, as the disc becomes denser, the track pitch decreases relatively, and cross-talk noise caused by the adjacent tracks is greatly generated. It is difficult to accurately detect a tracking error signal of a disc having a pitch.

That is, the light that is focused by the objective lens 9 for recording and reproduction, condensed into an optical spot on the disk, and then reflected is reflected on a mark such as a pit P formed on the track of the disk 10, as shown in FIG. By this, diffraction is performed in the 0th order and the ± first order. Therefore, the light received by the photodetector 1 substantially overlaps the 0th order diffracted light and the ± 1st order diffracted light. In this case, since the phase signal of the portion where the 0th order diffracted light and the ± 1st order diffracted light overlap at the same time has a different characteristic from the phase signal of the external part, in the case of narrow tracks, As described above, when the tracking error signal is detected by differentially detecting the detection signals of the partition plates in different diagonal directions, crosstalk noise is greatly generated, and thus it is difficult to accurately detect the tracking error signal.

Therefore, in order to detect the tracking error signal in which the crosstalk noise problem caused by the adjacent track is improved, a method of employing the eight-segment photodetector 20 has been proposed as shown in FIG. 3.

The eight-segment photodetector 20 is divided into four in the row direction corresponding to the radial direction of the disc, and divided into two in the column direction corresponding to the tangential direction of the disc track to have a 2 × 4 matrix arrangement. Here, each of the two-split plates A1 and A2 (B1 and B2) (C1 and C2) (D1 and D2) of the eight-segment photodetector 20 divides the split plate A of the photodetector 1 of FIG. Corresponding to (B) (C) (D), the partition plates A2, B2, C2 and D2 are located inside the partition plates A1, B1, C1 and D1.

At this time, the 8-segment photodetector 20 receives the portion where the 0th-order diffraction light and the ± 1st-order diffraction light overlap at the same time in the on-dividing plate A2, B2, C2, and D2, The remaining outer partition plates A1 (B1) (C1) (D1) are provided to receive the external portion.

The tracking error signal is detected from the detection signal of the eight-segment photodetector 20 as follows.

Referring to FIG. 4, a signal a1 + c1 obtained by summing detection signals a1 (c1) of the outer partition plates A1 and C1 in a diagonal direction and a detection signal of the inner partition plates A2 and C2. (a2) (a2 + c2) by amplifying the signal (a2 + c2), which is the sum of (c2), to a predetermined gain (k1), and adding the sum signal (a1 + c1 + k1 (a2 + c2)). Is input to the amplifier 21 to amplify the predetermined gain k2. Then, the detection signals b1 and b2 of the dividing plates B1, B2, D1 and D2 in a diagonal direction different from the signal k2 (a1 + c1 + k1 (a2 + c2)) output from this amplifier. The sum signal b1 + d1 + b2 + d2 of (d1) (d2) is input to the phase comparator 25, respectively, and the phases are compared to detect the tracking error signal TES '.

In this case, when k1 = 0 and k2 = 1, the signal input to the phase comparator is a1 + c1, b1 + d1, and the phase difference is obtained by using the sum signal of the detection signals in the diagonal direction of the outer partition plate. Corresponds to

In addition, when k1 ≠ 0, this corresponds to a case where a phase difference is obtained by summing detection signals of the inner dividing plate in one diagonal direction with detection signals of the outer dividing plate at a constant ratio.

The tracking error signal detection device as described above detects the detection signal of the inner partition plates a2 and c2 in one diagonal direction among the inner partition plates a2, b2, c2, and d2, in which the phase signal deterioration is large. Since the phase difference is obtained by summing with the detection signals of the outer dividers a1 and c1 at a constant ratio, a tracking error signal with reduced crosstalk noise can be detected.

However, since the tracking error signal detecting apparatus sums up the detection signals of the partition plates located in the diagonal direction and then calculates the phase difference, the tracking error signal has a small gain in the tracking error signal in the case of a relatively dense disc having a narrow track. Has the disadvantage of low precision.

In other words, the light received by the divider on different positions in the tangential direction of the track has different phase characteristics in the starting area and the ending area of a mark such as, for example, a pit.

Therefore, as in the conventional tracking error signal detection apparatus as described above, when the detection signals of the dividers in the diagonal direction are summed up unconditionally, phase characteristics along the tangential direction cancel each other, resulting in low gain of the tracking error signal, resulting in low precision. There are disadvantages to losing.

In addition, since the conventional tracking error signal detection apparatus uses the sum signal in the diagonal direction, a phase difference offset occurs between the sum signal due to the difference in mark depth such as the pit, and the shift of the objective lens (not shown) occurs. In this case, a tracking error signal offset is greatly caused.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a tracking error signal detection device capable of detecting a tracking error signal with improved gain characteristics and a reproduction signal detection method with reduced crosstalk noise. There is this.

1 is a configuration diagram showing an example of a conventional DPD tracking error signal detection apparatus;

2 is a perspective view showing light reflected / diffracted in a general recording medium;

3 and 4 are views showing a tracking error signal detection apparatus employing a conventional eight-segment photodetector;

5 is a schematic view showing a tracking error signal detection apparatus according to an embodiment of the present invention;

6 and 7 are graphs showing tracking error signals output from FIGS. 5 and 4, respectively;

8, 9, 11, 12, 13 and 14 are block diagrams showing another embodiment of the circuit part of FIG. 5, respectively.

FIG. 10 is a graph illustrating a tracking error signal TES2 output from the adder of FIG. 9;

15 is a block diagram showing the configuration of a circuit unit for detecting a playback signal according to the playback signal detection method of the present invention;

16 is a configuration diagram schematically illustrating an apparatus for detecting a tracking error signal according to another embodiment of the present invention;

FIG. 17 is a block diagram illustrating another embodiment from the time of FIG. 16.

<Explanation of symbols for main parts of drawing>

30,400 ... photodetector 50,450 ... circuit

51,51 ', 53,151,151', 153,165,167,240,290 ... Phase Comparator

59,59 ', 159,169,220,260,270,320,30 ... adder

60,161,162,163,164,210 ... operator 200,250,310 ... time delay

230,280,280,325,335 ... amplifiers

In order to achieve the above object, the present invention, a photodetector for receiving light reflected / diffracted in the recording medium; And a circuit unit for detecting a tracking error signal by calculating a detection signal of the photodetector, wherein the photodetector comprises:

The dividing boundary line is composed of four light receiving regions having a 2 × 2 matrix arrangement corresponding in parallel to the radial direction and the track tangential direction of the recording medium, wherein the circuit portion is located in the same row. The phases between the light receiving regions are compared with each other, and then a tracking error signal is detected from the phase difference signal.

Here, the photodetector is divided into two light receiving regions A1 and A2 (B1 and B2) (C1 and C2) (D1 and D2) arranged in the counterclockwise direction and divided into two, substantially parallel to the tangential direction. 8 independent photoelectric conversions, each of which is arranged inside the partitions A1, B1, C1, and D1, which form a matrix arrangement of × 4, and each of the partition plates A2, B2, C2, and D2 It is preferable that it consists of the partition plates A1 (A2) (B1) (B2) (C1) (C2) (D1) (D2).

In this case, the circuit unit comprises: a first phase comparator for comparing the phases of the detection signals of the pair of outer division plates located in the first row and outputting the phase difference signal; A second phase comparator for comparing the phases of the detection signals of the pair of outer division plates located in the second row and outputting the phase difference signal; And an adder configured to sum the phase difference signals from the first and second phase comparators and output a tracking error signal.

The circuit unit may further include first and second phase comparators configured to compare phases between the detection signals of the outer partition plates and the inner partition plates positioned in the first row, respectively, and output a phase difference signal; Third and fourth phase comparators for comparing the phases between the detection signals of the outer partition plates and the inner partition plates located in the second row with each other and outputting a phase difference signal; A first adder for summing the phase difference signals from the first and third phase comparators to detect the tracking error signal TES1 by the detection signals of the outer partition plates; A second adder for summing the phase difference signals from the second and fourth phase comparators to detect the tracking error signal TES2 due to the detection signal of the inner divisions; And a calculator for outputting a tracking error signal TES by summing the tracking error signals TES1 and TES2 of the first and second adders.

The circuit unit may further include a first operator configured to amplify a detection signal of one inner partition plate located in a first row to a predetermined gain and add the detected signal to the detection signal of the outer partition plate; A second operator which amplifies the detection signal of the other inner partition plate located in the first row to a predetermined gain and adds it to the detection signal of the outer partition plate; A third operator for amplifying the detection signal of the one inner partition plate located in the second row with a predetermined gain and summing it with the detection signal of the outer partition plate; A fourth operator for amplifying the detection signal of the other inner partition plate located in the second row with a predetermined gain and summing it with the detection signal of the outer partition plate; A first phase comparator for comparing phases between sum signals output from the first and second operators and outputting a phase difference signal; A second phase comparator for comparing phases between sum signals output from the third and fourth operators and outputting a phase difference signal; And an adder for summing the phase difference signals from the first and second phase comparators and outputting a tracking error signal.

Here, the photodetector is arranged in the counterclockwise direction so that the four light receiving regions (A) (B) (C) (D) are spaced apart from each other in the radial direction by a predetermined interval, and the circuit portion is located in the first row. A first phase comparator for comparing phases between the detection signals of the paired split plates and outputting the phase difference signals; A second phase comparator for comparing phases between detection signals of a pair of dividers positioned in a second row and outputting a phase difference signal; And an adder for summing the phase difference signals of the first and second phase comparators to output a tracking error signal.

According to another aspect of the invention, the photodetector for receiving light reflected / diffracted in the recording medium; And a circuit unit which detects a tracking error signal by calculating a detection signal of the photodetector, wherein the photodetector has a row direction and a column direction of the division boundary in a radial direction of the recording medium. And four light-receiving regions having a 2x2 matrix arrangement corresponding substantially parallel to the track tangential radial direction, wherein the circuit section time-delays the detection signals of the light-receiving regions located in one row, Characterized in that it is provided to detect the tracking error signal by comparing the phase between the detection signals of the light receiving region located in the diagonal direction with each other.

Further, the present invention is a reproduction signal detection method for reading an information signal recorded on the recording medium from a detection signal of a photodetector for receiving light reflected / diffracted from the recording medium, wherein the photodetector is arranged in a row of the division boundary line. Four light-receiving regions (a1, a2) (b1, b2) (c1) arranged in a counterclockwise direction in a 2x2 matrix arrangement in which a direction and a column direction correspond approximately parallel to the radial and track tangential directions of the recording medium. (c2) (d1, d2) are divided into two substantially parallel to each other in the tangential direction to form a 2 × 4 matrix arrangement, and the dividers a2, b2, c2, and d2 divide the dividers a1 and b1. (c1) (d1), each of which is arranged inside of each of eight divided plates (a1) (a2) (b1) (b2) (c1) (c2) (d1) (d2) independently photoelectric conversion, (A) time delaying the detection signal of the inner and outer partition plates located in the first or second row; (B) amplifying a time delay signal of one outer partition plate and a detection signal of the outer partition plate positioned in a diagonal direction with a predetermined gain k1; (C) amplifying the time delay signal of the other outer partition plate and the detection signal of the outer partition plate located in the diagonal direction with a predetermined gain k2; (D) adding the signals generated in the above steps (b) and (c), the time delay signals of the inner partition plates, and the detection signals of the inner partition plates located in the diagonal direction to detect the reproduction signal of the recording medium. It characterized by including.

At this time, the sum of the gain k1 and k2 is preferably a constant.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

5 is a configuration diagram schematically showing the configuration of the tracking error signal detection apparatus according to the first embodiment of the present invention.

Referring to the drawings, the tracking error signal detecting apparatus according to the present invention includes a photodetector 30 for receiving light reflected / diffracted from a recording medium such as a disk (10 of FIG. 2) and a detection signal of the photodetector 30. And a circuit unit 50 for detecting the tracking error signal TES. Here, the photodetector 30 receives the light reflected from the recording medium and enters the detection signal, and the detection signal is used to detect a reproduction signal and a tracking error signal of the recording medium.

The photodetector 30 has four light-receiving regions 30a: A1, A2 (30b: B1, B2) (30c: C1, C2) (30d: D1, D2) arranged in a 2 × 2 matrix and arranged counterclockwise. ). The light receiving regions 30a, 30b, 30c and 30d are divided in two in the row direction, respectively.

Thus, the photodetector 30 is arranged in two rows and four columns of 2 × 4 matrix, each of the eight divided plates A1, A2, B1, B2, C1, C2, D1 independently photoelectric conversion. (D2), and the arrangement order of the outer partition plates A1 (B1) (C1) (D1) and the partition plates (A2) (B2) (C2) (D2) respectively disposed inside thereof is counterclockwise. Follow the direction.

At this time, the boundary lines for dividing the eight-split plates A1, A2, B1, B2, C1, C2, D1, and D2 into two rows and four columns respectively represent a radial direction and a track tangential direction of the recording medium. Corresponds roughly side by side.

The inner partitions A2, B2, C2, and D2 have a narrow width in the radial direction and a long form in the tangential direction, and the entire width thereof is, for example, the zero-order diffraction reflected / diffracted on the recording medium. It is preferable that the light and the first-order diffracted light have a size capable of receiving the overlapped area at the same time. Here, the zeroth order and ± first order diffracted light reflected / diffracted by the recording medium are the same as those described with reference to FIG.

According to a preferred embodiment of the present invention, the circuit unit 50 is provided to compare the phases between the light receiving regions located in the same row, respectively, and then detect the tracking error signal from the phase difference signal.

For example, as shown in FIG. 5, the circuit unit 50 includes a pair of phase comparators 51 and 53 for comparing the phases of input signals with each other, and from the pair of phase comparators 51 and 53. And an adder 59 for summing the phase difference signals.

Detection signals a1 and b1 of the outer partitions A1 and B1 positioned in the first row are input to the one phase comparator 51, and the phases are compared, and the second phase comparator 53 is connected to the second phase comparator 53. Phases are compared by detecting the detection signals c1 and d1 of the outer partition plates C1 and D1 positioned in the row.

Therefore, the tracking error signal TES output from the adder 59 is the same row input from the pair of phase comparators 51 and 53, that is, the outer partition plate A1 (on the same line in the tangential direction) ( The phase difference signal between the detection signals a1 and b1 of B1 and the phase difference signal between the detection signals c1 and d1 of the outer partition plate C1 and D1 are summed.

FIG. 6 is a graph showing a tracking error signal TES detected by the tracking error signal detecting apparatus according to an embodiment of the present invention. FIG. 7 is a conventional tracking error as shown in FIGS. 3 and 4. This is a graph showing the tracking error signal TES 'detected by the signal detection apparatus. Here, the horizontal axis represents the movement of the optical spot moving radially across the track on the recording medium, and the vertical axis represents the change of the tracking error signal according to the movement of the optical spot in arbitrary units.

6 and 7, the tracking error signal TES detected through the tracking error signal detection apparatus according to an embodiment of the present invention is the outer partition plate A1 of the conventional photodetector 20 of FIG. 3. The sum signal a1 + c1 (b1 + d1) of the diagonal signals of the detection signals a1 (b1) (c1) and d1 of (B1) (C1) and (D1) is first obtained, and then the phases are compared. the gain compared to the tracking error signal (TES _'.) detected by the system can be seen more is great.

In another embodiment, the circuit unit 50 may detect the detection signals a1 (b1) (c1) and d1 of the outer partition plates A1 (B1) (C1) and D1, as shown in FIG. Instead, it may be provided to detect the tracking error signal using the detection signals a2, b2, c2 and d2 of the inner dividers A2, B2, C2 and D2.

That is, one phase comparator 151 receives the detection signals a2 and b2 of the inner partition plates A2 and B2 positioned in the first row and outputs the phase difference signals. The other phase comparator 153 is inputted with detection signals c2 and d2 of the inner dividing plates C2 and D2 located in the second row, and outputs the phase difference signal. The adder 159 adds the phase difference signals and outputs a tracking error signal TES.

In a more preferred embodiment, the circuit unit 50, as shown in Figure 9, the inner and outer partitions (A1) (A2) (B1) (B2) (C1) (C2) (D1) (D2) 5 and 8 are appropriately combined to detect the tracking error signal TES using all of the detection signals a1 (a2) (b1) (b2) (c1) (c2) (d1) and (d2). Has a configuration. That is, the tracking error signal (TES1: as shown in Fig. 6) calculated from the detection signals a1 (b1) (c1) (d1) of the outer partitions A1 (B1) (C1) (D1). And the tracking error signal TES2 calculated from the detection signals a2, b2, c2, and d2 of the inner partitions A2, B2, C2, and D2, are tracked by adding up the tracking error signal TES2. It is arranged to detect an error signal TES. Here, the TES2 is a tracking error signal calculated from the detection signals a2 (b2) (c2) and d2 of the inner partitions A2, B2, C2 and D2, which are obtained in the adder of FIG. Corresponding to the output tracking error signal, as shown in FIG.

The calculator 60 amplifies one tracking error signal TES2 of the tracking error signals TES1 and TES2 output from the adders 59 and 159 by a predetermined gain k, and then amplifies them TE1 (k * TE2). ) Is added to detect the tracking error signal (TES = TES1 + k * TES2).

Here, the calculator 60 amplifies the tracking error signal TES1 to a predetermined gain, or adds an appropriate gain to both the tracking error signals TES1 and TES2 and adds them to detect the tracking error signal TES. It may be arranged.

As another embodiment, the circuit unit 50 has a simpler structure than that of FIG. 9 to obtain sum signals of inner and outer partition plates positioned in the same diagonal direction, respectively, and to divide the inner parts. The phase difference signal between the sum signal of the plate and the sum signal of the outer partition plate may be summed to detect the tracking error signal TES.

That is, the sum signal a1 + c1 of the detection signals a1 (c1) of the outer partition plates A1 and C1 in one diagonal direction and the outer partition plates B1 and D1 in the other diagonal direction The sum signals b1 + d1 of the detection signals b1 and d1 are input to the phase comparator 51 ', respectively, and the phases between the sum signals are compared.

Similarly, the sum signal a2 + c2 of the detection signals a2 and c2 of the inner dividing plates A2 and C2 in one diagonal direction, and the inner dividing plates B2 and D2 in the other diagonal direction. The sum signals b2 + d2 of the detection signals b2 and d2 are input to the phase comparators 151 ', respectively, and the phases between the sum signals are compared.

The phase difference signals output from the phase comparators 51 'and 151' are summed in the adder 59 ', and the tracking error signal TES is output from the adder 59'.

Here, the adder 59 amplifies at least one phase difference signal among phase signals output from the phase comparators 51 'and 151' with a predetermined gain, and adds them to detect the tracking error signal TES. May be

As another embodiment, as shown in FIG. 12, the circuit unit 50 may add up a sum signal obtained by adding up detection signals of an outer partition plate corresponding to a signal obtained by amplifying the detection signal of each inner partition plate by a predetermined gain (k). The phases may be compared with each other for each row, and the phase difference signals may be summed to detect a tracking error signal.

That is, detection signals a1 and a2 of the outer and inner partition plates A1 and A2 constituting the light receiving regions A1 and A2 positioned in the first row are input to the first operator 161. The first operator 161 amplifies the detection signal a2 to a predetermined gain k, and then adds the detection signal a2 to the detection signal a1. Therefore, the output signal becomes (a1 + k * a2).

Similarly, the detection signals of the remaining light receiving areas B1 and B2 (C1 and C2) (D1 and D2) are also input to the second to fourth operators 162, 163 and 164, respectively, and are calculated. The fourth operators 162, 163, and 164 output the calculation signals (b1 + k * b2), (c1 + k * c2), and (d1 + k * d2), respectively.

The signals detected in the light receiving regions A1 and A2 (B1 and B2) located in the first row, respectively, and via the first and second operators 161 and 162 are out of phase in the first phase comparator 165. Are compared with each other. The signals detected in the light receiving regions C1 and C2 (D1 and D2) located in the second row, respectively, and via the third and fourth operators 153 and 164 are out of phase in the second phase comparator 167. Are compared with each other.

The phase difference signals output from the first and second phase comparators 165 and 167 are added by the adder 169, and the tracking error signal TES is output by the adder 169.

The circuit part 50 having such a structure adds the detection signals of the outer and inner dividing plates constituting the light receiving regions 30A, 30B, 30C, and 30D to the detection signals of the inner dividing plates, and then adds them. Since the signal phase differences from the partition plates positioned in the same row are first compared, the signal distortion between the detection signals of the outer and inner partition plates is corrected, so that the tracking error signal having a large gain can be obtained as in the above-described embodiments. Can be detected.

Referring to FIG. 13, which shows another embodiment, the circuit unit 50 detects the detection signals c1 and c2 of the partition plates C1, C2, D1, and D2 located in one row, for example, the second row. (d1) (d2) is time-delayed, and the time delay signal and the detection signal of the partition plate located in the diagonal direction are appropriately calculated, and then the tracking error signal is detected by comparing the phase between the calculation signals. Can be.

That is, the detection signals c1, c2, d1, and d2 of the partition plates C1, C2, D1, and D2 located in the second row are delayed while passing through the time delay 200. Are converted into signals c11, c22, d11, and d22.

Detected by the detection signals a1 (a2) of some of the partition plates A1 (A2) located in the first row and the partition plates C1 (C2) in the diagonal direction and time delayed by the time delay unit 200. Signals c11 and c22 are input to the calculator 210. The calculator 210 sums and outputs the input signals a1 (a2) (c11) and c22. At this time, the calculator 210 amplifies the signals a2 and c22 from the inner partitions A2 and C2 to a predetermined gain k1 and then outputs the signals from the outer partitions A1 and C1. It is preferable that it is provided so that it may add up to (a1) (c11).

The signal a1 + c11 + k1 * (a2 + c22) output from the operator 210 is amplified by the amplifier 230 again to a predetermined gain k2, and the amplifier 230 receives the signal k2 * (a1 +). c11 + k1 (a2 + c22)) is output.

Detected by the detection signals b1 and b2 of the remaining dividers B1 and B2 positioned in the first row and the dividers D1 and D2 in the diagonal direction thereof, and time-delayed in the time delay unit 200. The signals d11 and d22 are summed in the adder 220, and the sum signal b1 + d11 + b2 + d22 is outputted in the adder 220.

The signals output from the amplifier 230 and the adder 220 are input to the phase comparator 240, and the phase comparator 240 outputs a tracking error signal TES by comparing phases between the input signals.

The circuit part 50 having such a configuration time delays the detection signals c1 (c2) (d1) d2 of the divided plates C1, C2, D1 and D2 on the same line in one tangential direction. While simultaneously amplifying the signals a1 (a2) (c11) and c22 from the partitions A1 (A2) (C1) (C2) on one diagonal line, and then amplifying a predetermined gain (k1) (k2). This is compared with the sum signal of the signals b1, b2, d11, and d22 from the partitions B1, B2, D1, and D2 on different diagonal lines to obtain the tracking error signal TES. Detect.

Therefore, in the case where the mark depth such as the pit of the recording medium is changed, the signal deterioration is large because the detection signal in the diagonal direction is summed as it is in the conventional apparatus, whereas in the present invention, the detection signal of the partition plate on the same diagonal line Is first calculated and then the phase difference between them is detected. However, since the tracking error signal is detected through the time delay and amplification process as described above, the problem of phase degradation due to signal distortion caused by the change of the mark depth is greatly improved. Even when a shift occurs, it is possible to detect a tracking error signal in which the offset is greatly reduced.

Further, in the present invention, even if the phase characteristics along the tangential direction are not canceled with each other even when they have different phase characteristics in the start region and the end region of a mark such as a pit, a tracking error signal having a large gain can be obtained.

On the other hand, as shown in FIG. 13, instead of using all of the detection signals of the inner and outer partitions A2, B2, C2, D2, A1, B1, C1, D1, as shown in FIG. As described above, the circuit unit 50 may be provided to detect the tracking error signal using only the detection signals a1 (b1) (c1) and d1 of the outer partition plates A1 (B1) (C1) and D1. It is possible. In this case, the calculator 210 of FIG. 13 is replaced with an adder 260.

That is, the detection signal c1 (d1) of the outer partition plates C1 (D1) located in one row, for example, the second row, is a time delayed signal c11 (d11) via the time delay unit 250. Is converted.

The signal c11 detected by the detection signal a1 of the outer partition plate A1 located in the first row and the partition plate C1 located in the diagonal direction and delayed by the time delay unit 250 is one adder ( The sum signal a1 + c11 is amplified by a predetermined gain k in the amplifier 280. The detection signal b1 of the outer partition plate B1 located in the first row and the partition plate D1 located in the diagonal direction thereof and the time delayed signal d11 in the time delay unit 250 are added to the other adder ( 270). The output signal k (a1 + c11) of the amplifier 280 and the output signal b1 + d11 of the adder 270 are input to the phase comparator 290, and the phase comparator 290 is a phase of two input signals. Are compared with each other to output a tracking error signal (TES).

As in the above embodiment, the photodetector 30 of the eight-split plates A1 (A2) (B1) (B2) (C1) (C2) (D1) (D2) as shown in FIG. 5 is employed. In this case, the recording and reproducing apparatus includes a reproducing signal detecting circuit unit 300 as shown in Fig. 15 to detect the reproducing signal as follows.

The detection signals c1, c2, d1 and d2 of the dividers C1, C2, D1 and D2 located in one row of the photodetector 30, for example, the second row, are time delay units. Input to 310 is time delayed.

The time delay signal c11 of the detection signal c1 of the one outer partition plate C1 via the time delay unit 310 and the detection signal a1 of the outer partition plate A1 positioned in the diagonal direction are The summation signal a1 + c11 is amplified by the first amplifier 325 to a predetermined gain k1.

The time delay signal d11 of the detection signal d1 of the other outer partition plate D1 via the time delay unit 310 and the detection signal b1 of the outer partition plate B1 positioned in the diagonal direction are The summation signal b1 + d11 is amplified by a predetermined gain k2 in the second amplifier 335.

The time delay signals c22 and d22 of the detection signals c2 and d2 of the inner partition plates C2 and D2 output from the time delay unit 310 and the inner partition plates A2 positioned in the first row. The detection signal a2 (b2) of (B2), the output signals k1 (a1 + c11) and k2 (b + d11) of the first and second amplifiers 325 and 335 are all added to the third adder 340. The third adder 340 sums all the input signals and adds the sum signal, that is, the information reproduction signal (a2 + b2 + c22 + d22 + k1 * (a1 + c11) + k2 *) recorded on the recording medium. (b2 + d11)) is output.

When the reproduction signal is detected through this process, the detection signals c1, c2, d1 and d2 of the split plates C1, C2, D1 and D2 on the same line in one tangential direction are timed. Delays, amplifies the signal from the outer dividers in the diagonal direction to a predetermined gain, and then sums up the signals to detect the reproduced signal, so that different phase characteristics and inner divisions are made in the starting and ending regions of the mark such as the pit. Since the signal distortion due to the phase characteristic difference between the detection signal of the plates and the detection signal of the outer partition plates can be corrected, there is an advantage that a high quality reproduction signal with reduced crosstalk can be obtained.

In this case, it is preferable that the sum of the gains k1 and k2 (k1 + k2) is a constant (please explain why a constant is good).

16 is a diagram schematically illustrating a configuration of a tracking error signal detection apparatus according to another embodiment of the present invention. Referring to the drawings, the tracking error signal detection apparatus according to another embodiment of the present invention is a photodetector 400 having four light receiving regions, that is, four partition plates (A) (B) (C) (D) and And a circuit unit 450 for detecting a tracking error signal from the detection signal of the photodetector 400.

The photodetector 400 is provided such that the four dividers A, B, C, and D form a 2 × 2 matrix arrangement of two rows and two columns and each independently photoelectrically converts. The order of arranging the partition plates A, B, C, and D is in the counterclockwise direction, and the boundary lines divided into two rows and two columns correspond to the radial direction and the track tangential direction of the recording medium, respectively.

In the present embodiment, the partition plates A and D are spaced apart from each other by a predetermined distance d in the radial direction of the recording medium. At this time, the divider (A) (D) and the divider (B) (C) are spaced apart so that the region where the zeroth order diffraction light and the ± first order diffraction light overlap at the same time are reflected or diffracted on the recording medium. Is preferred. Therefore, the partition plates A, B, C, and D are substantially the same as the configuration of the outer partition plates A1, B1, C1, and D1 of FIG.

As shown in FIG. 16, the circuit unit 450 detects signals (a) and (b) of a divider on the same line in the tangential direction, for example, the divider (A) and B located in the first row. ), The phases between the detection signals (c) and (d) of the dividers (C) and (D) located in the second row may be compared with each other, and then the tracking error signal may be detected from the phase difference signal. In this case, since the configuration of the circuit unit 450 and the tracking error signal detection process are substantially the same as those of FIG. 5, a detailed description thereof will be omitted.

Meanwhile, as shown in FIG. 17, the circuit unit 450 delays the detection signal (c) (d) of the splitter plate (C) (D) located in one row, for example, the second row. A phase between the delayed signals c 'and d' and the detection signals a and b of the partition plates A and B located in the first row may be compared with each other to detect the tracking error signal. have. At this time, since the configuration of the circuit unit 450 and the tracking error signal detection process are substantially the same as in FIG. 14, description thereof is omitted.

In the tracking error signal detected in the above embodiments, when the period of the channel clock of the recording / reproducing apparatus is Tw and the detected average phase difference time is Δt, the optical spot is 0.1 μm at the center of the pit or mark string recorded on the recording medium. In the case of deviation, the minimum value of? T / Tw is approximately 0.5, and when the positive maximum value of the tracking error signal is T1 and the negative minimum value is T2, the maximum value of | (T1-T2) / (T1 + T2) | is approximately It is preferable that it is 0.2.

In addition, in the above embodiments, the phase comparator selectively blocks or amplifies the signal according to the frequency band of the input signal, binarizes, compares the phase of the binarized signal, and integrates the phase-compare signal. The phase is compared to output a tracking error signal.

The tracking error signal detection apparatus according to the present invention as described above has a large gain and greatly improves the phase degradation problem due to signal distortion caused by a change in mark depth, so that even when a lens shift occurs, the tracking error signal rarely causes an offset. Can be detected. In addition, as in the conventional apparatus, it is possible to detect a tracking error signal in which crosstalk noise is reduced.

Therefore, by employing the tracking error signal detection apparatus according to the present invention, even in the case of a high density recording medium having a relatively narrow track, high precision tracking control is possible.

In addition, according to the reproduction signal detection method according to the present invention, the signal distortion and the detection of the inner and outer partitions occurring in the region of the start and end of the mark such as the pit even when the information signal of the high density recording medium having a relatively narrow track is reproduced Signal distortion and the like due to the phase characteristic difference between the signals can be corrected, so that a high quality reproduction signal with reduced crosstalk can be detected.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, various embodiments are possible within the scope of the technical idea of the present invention.

Claims (20)

A photodetector for receiving the reflected / diffracted light on the recording medium; And a circuit unit for detecting a tracking error signal by calculating a detection signal of the photodetector, the tracking error signal detecting apparatus comprising: The photodetector, A row and column direction of the dividing boundary line is composed of four light-receiving areas forming a 2x2 matrix arrangement corresponding substantially parallel to the radial direction and the track tangential direction of the recording medium, The circuit portion, And comparing the phases between the light-receiving regions located in the same row with each other, and then detecting the tracking error signal from the phase difference signal. The method of claim 1, wherein the photodetector, Four light-receiving areas A1, A2, B1, B2, C1, C2, D1, D2 arranged in the counterclockwise direction are divided into two approximately parallel to the tangential direction to form a 2 × 4 matrix arrangement. Eight split plates A1 (A2) for photoelectric conversion independently of each of the split plates A2, B2, C2, and D2 respectively disposed inside the split plates A1, B1, C1, and D1. (B1) (B2) (C1) (C2) (D1) and (D2). The method of claim 2, wherein the circuit portion, A first phase comparator for comparing the phases of the detection signals of the pair of outer division plates located in the first row with each other and outputting the phase difference signal; A second phase comparator for comparing the phases of the detection signals of the pair of outer division plates located in the second row and outputting the phase difference signal; And And an adder for summing the phase difference signals from the first and second phase comparators to output a tracking error signal. The method of claim 2, wherein the circuit portion, A first phase comparator for comparing the phases of the detection signals of the pair of inner division plates located in the first row with each other and outputting the phase difference signal; A second phase comparator for comparing the phases of the detection signals of the pair of inner division plates positioned in the second row with each other and outputting the phase difference signal; And And an adder for summing the phase difference signals from the first and second phase comparators to output a tracking error signal. The method of claim 2, wherein the circuit portion, First and second phase comparators for comparing the phases between the detection signals of the outer partition plates and the inner partition plates positioned in the first row with each other and outputting a phase difference signal; Third and fourth phase comparators for comparing the phases between the detection signals of the outer partition plates and the inner partition plates located in the second row with each other and outputting a phase difference signal; A first adder for summing the phase difference signals from the first and third phase comparators to detect the tracking error signal TES1 by the detection signals of the outer partition plates; A second adder for summing the phase difference signals from the second and fourth phase comparators to detect the tracking error signal TES2 due to the detection signal of the inner divisions; And And a computing unit for outputting a tracking error signal (TES) by summing the tracking error signals (TES1) and TES2 of the first and second adders. The method of claim 5, wherein the calculator, Tracking amplifying at least one of the tracking error signals TES1 and TES2 output from the first and second adders to a predetermined gain, and then adding them to detect the tracking error signal TES. Error signal detection device. The method of claim 2, wherein the circuit portion, A first phase comparator for comparing a phase between a sum signal of detection signals of the outer division plates in one diagonal direction and a sum signal of detection signals of the outer division plates in another diagonal direction and outputting a phase difference signal; A second phase comparator for comparing a phase between a sum signal of detection signals of the inner division plates in one diagonal direction and a sum signal of detection signals of the inner division plates in another diagonal direction and outputting a phase difference signal; And And an adder which adds phase difference signals from the first and second phase comparators to detect a tracking error signal. The method of claim 2, wherein the circuit portion, A first operator for amplifying the detection signal of the one inner partition plate located in the first row with a predetermined gain and summing it with the detection signal of the outer partition plate; A second operator which amplifies the detection signal of the other inner partition plate located in the first row to a predetermined gain and adds it to the detection signal of the outer partition plate; A third operator for amplifying the detection signal of the one inner partition plate located in the second row with a predetermined gain and summing it with the detection signal of the outer partition plate; A fourth operator for amplifying the detection signal of the other inner partition plate located in the second row with a predetermined gain and summing it with the detection signal of the outer partition plate; A first phase comparator for comparing phases between sum signals output from the first and second operators and outputting a phase difference signal; A second phase comparator for comparing phases between sum signals output from the third and fourth operators and outputting a phase difference signal; And And an adder for summing the phase difference signals from the first and second phase comparators to output a tracking error signal. The method of claim 1, wherein the photodetector, Four light receiving regions A, B, C, and D are arranged counterclockwise to be spaced apart from each other in the radial direction by a predetermined interval, The circuit portion, A first phase comparator for comparing phases between detection signals of a pair of dividers positioned in a first row and outputting a phase difference signal; A second phase comparator for comparing phases between detection signals of a pair of dividers positioned in a second row and outputting a phase difference signal; And And an adder for summing the phase difference signals of the first and second phase comparators to output a tracking error signal. The tracking error signal according to any one of claims 1 to 9, wherein When the period of the channel clock of the recording and reproducing apparatus is Tw and the detected average phase difference time is Δt, If the light spot is 0.1 μm out of the center of the pit or mark string recorded on the recording medium, the minimum of Δt / Tw is approximately 0.5, Wherein the maximum value of the absolute value of (T1-T2) / (T1 + T2) is approximately 0.2 when the positive maximum value of the tracking error signal is T1 and the negative minimum value is T2. The phase comparator according to any one of claims 1 to 9, Selectively blocking or amplifying according to a frequency band of the input signal; Binarization step; Comparing the phases of the binarized signals; And Integrating the phase-compare signal, the tracking error signal detection device, characterized in that to compare the phase of the input signal and output the phase difference signal. A photodetector for receiving the reflected / diffracted light on the recording medium; And a circuit unit for detecting a tracking error signal by calculating a detection signal of the photodetector, the tracking error signal detecting apparatus comprising: The photodetector, Row and column directions of the dividing boundary line are made up of four light receiving regions having a 2x2 matrix arrangement corresponding substantially parallel to the radial direction and the track tangent radial direction of the recording medium, The circuit portion, A time delay of the detection signal of the light receiving area located in one row, and comparing the phase between the time delayed signal and the detection signal of the light receiving area located in the diagonal direction to detect a tracking error signal. Error signal detection device. The method of claim 12, wherein the photodetector, Four light-receiving areas A1, A2, B1, B2, C1, C2, D1, D2 arranged in the counterclockwise direction are divided into two approximately parallel to the tangential direction to form a 2 × 4 matrix arrangement. Eight split plates A1 (A2) for photoelectric conversion independently of each of the split plates A2, B2, C2, and D2 respectively disposed inside the split plates A1, B1, C1, and D1. (B1) (B2) (C1) (C2) (D1) and (D2). The method of claim 13, wherein the circuit portion, A time delay unit for time delaying the detection signal of the divider located in the first row or the second row and outputting the time delay signal; The time delay signal of the detection signals of one outer and inner partition plates via the time delay unit and the detection signals of the outer and inner partition plates positioned in the diagonal direction are inputted, and a sum signal from the detection signals of the inner partition plates is received. A calculator for amplifying to a predetermined gain k1 and summing this signal with signals from the detection signals of the outer partitions; An adder for summing the time delay signals of the detection signals of the other outer and inner partition plates via the time delay and the detection signals of the outer and inner partition plates located in the diagonal direction; An amplifier for amplifying the signal from one of the calculator and the adder to a predetermined gain (k2); And And a phase comparator for detecting a tracking error signal by comparing a phase of an output signal of the amplifier and a signal output from another one of the calculator and the adder. The method of claim 13, wherein the circuit portion, A time delay unit for time delaying the detection signal of the outer partition plate located in the first or second row and outputting the time delay signal; A first adder for summing the time delay signal of the one outer partition plate via the time delay unit and the detection signal of the outer partition plate located in a diagonal direction thereof; A second adder for summing the time delay signal of the other outer partition plate via the time delay unit with the detection signal of the outer partition plate located in the diagonal direction; An amplifier for amplifying a signal output from one of the first and second adders to a predetermined gain (k); And And a phase comparator for detecting a tracking error signal by comparing a phase of an output signal of the amplifier and a signal output from another adder of the first and second adders. The method of claim 12, wherein the photodetector, Four light receiving regions A, B, C, and D are arranged counterclockwise to be spaced apart from each other in the radial direction by a predetermined interval, The circuit portion, A time delay unit for time delaying the detection signals of the pair of dividers located in the first or second row and outputting the time delay signal; A first adder for summing the time delay signals from the one partition plate via the time delay section with the detection signals of the partition plates located in the diagonal direction; A second adder for summing the time delay signals of the other partition plates via the time delay unit and the detection signals of the partition plates located in a diagonal direction thereof; An amplifier for amplifying a signal output from one of the first and second adders to a predetermined gain (k); And And a phase comparator for detecting a tracking error signal by comparing a phase of an output signal of the amplifier and a signal output from another adder of the first and second adders. The method according to any one of claims 12 to 16, wherein the tracking error signal detected is: When the period of the channel clock of the recording and reproducing apparatus is Tw and the detected average phase difference time is Δt, If the light spot is 0.1 μm out of the center of the pit or mark string recorded on the recording medium, the minimum of Δt / Tw is approximately 0.5, Wherein the maximum value of the absolute value of (T1-T2) / (T1 + T2) is approximately 0.2 when the positive maximum value of the tracking error signal is T1 and the negative minimum value is T2. The phase comparator according to any one of claims 14 to 16, Selectively blocking or amplifying according to a frequency band of the input signal; Binarization step; Comparing the phases of the binarized signals; And And integrating the phase-compare signal, thereby comparing the phase of the input signal to output a tracking error signal. A reproduction signal detection method for reading an information signal recorded on the recording medium from a detection signal of a photodetector for receiving light reflected / diffracted from a recording medium, The photodetector, Four light-receiving areas (a1, a2) (b1) arranged in a counterclockwise direction, forming a 2x2 matrix arrangement whose row and column directions of the dividing boundary line approximately correspond to the radial direction and the track tangential direction of the recording medium. (b2) (c1, c2) (d1, d2) are divided into two substantially parallel to each other in the tangential direction to form a 2 × 4 matrix, and the dividers a2, b2, c2 and d2 are divided (a1) (b1) (c1) (d1) Eight divided plates each independently arranged photoelectric conversion (a1) (a2) (b1) (b2) (c1) (c2) (d1) (d2) ), (A) time delaying the detection signal of the inner and outer partition plates located in the first or second row; (B) amplifying a time delay signal of one outer partition plate and a detection signal of the outer partition plate positioned in a diagonal direction with a predetermined gain k1; (C) amplifying the time delay signal of the other outer partition plate and the detection signal of the outer partition plate located in the diagonal direction with a predetermined gain k2; (D) adding the signals generated in the above steps (b) and (c), the time delay signals of the inner partition plates, and the detection signals of the inner partition plates located in the diagonal direction to detect the reproduction signal of the recording medium. Playback signal detection method comprising a. 20. The method of claim 19, wherein the sum of the gains k1 and k2 is a constant.