JP3756918B2 - Optical disk device manufacturing method, phase difference adjusting method, and adjusting device - Google Patents

Description

The present invention relates to a method of manufacturing an optical disc apparatus including a wobble signal detection circuit, a phase difference adjustment method, and an adjustment apparatus.

  Optical discs such as DVD + R and DVD + RW have information tracks that are wobbled (meandered) at a fixed period, and the tracks are previously formed in a spiral on the substrate of the optical disc by the phase modulation method (PSK method = Phase Shift Keying). Things are used.

  In order to create ADIP (Address In Pre-groove) information and the like by detecting and creating a wobble signal based on the light receiving signal of a light receiving element such as a DVD + R, DVD + RW, etc. As the wobble signal detection circuit to be provided, a circuit as shown in FIG. 14 is used. The wobble signal detection circuit in the illustrated example shows only the first half until the digital wobble signal and the analog wobble signal are generated based on the voltage signals VA to VD obtained from the respective light receiving element regions of the four-divided light receiving elements.

  First, each of the voltage signals VA to VD is individually sampled and held by the sample and hold circuit (S / H) 100, and VA, VC, VB, and VC are added by the adder 101, and then 0.5 by the multiplier 102. Double processing is performed to calculate 0.5 × (VA + VC) and 0.5 × (VB + VC). Thereafter, the balance AGC circuit 103 balances the amplitude of 0.5 × (VA + VC) and 0.5 × (VB + VC), and the subtractor 104 gives 0.5 × (VA + VC) −0.5 × (VB + VC). An operation is performed and input to the filter circuit 105. The filter circuit 105 includes a BPF path for a digital wobble signal by a BPF (band pass filter) 106, and an HPF + LPF path for an analog wobble signal by an HPF (high pass filter) 107 and an LPF (low pass filter) 108. Consists of. On the output side of the BPF 106, for example, a binarizer 109 using a comparator is provided.

  Here, the problem is variation in the cut-off frequency fc of the LPF 108 part of the HPF + LPF path. The accuracy of the cut-off frequency fc of the LPF 108 is strict, and variations among circuits become conspicuous during mass production. If the cut-off frequency fc varies, the phase of the analog wobble signal is shifted back and forth from the ideal phase (solid line) according to the height as shown in FIG. When recording information on an optical disc such as a DVD + RW, the recording start position is set based on the analog wobble signal. Therefore, if the phase of the analog wobble signal is shifted, the recording start position is also optimal as shown in FIG. It will shift from the position.

  In order to solve this problem, for example, according to Patent Document 1, when overwriting a recorded disc, reproduced data from the recorded portion is used as a reference signal to the clock generator. In the area where information is newly recorded, a method has been proposed in which the clock generation signal recorded in the recorded part is switched in advance to match the clock phase and the recording start position is set to the optimum value. .

  As a method other than Patent Document 1, a disk (hereinafter, referred to as a mirror disk) in which a 14T sync frame portion is provided with a 6T mirror portion (a portion that cannot be written and has high reflectivity) is adjusted to an optimum recording position. There is a way. In this adjustment method, 1 ECC (1 recording block of DVD) is recorded on a mirror disk, and after recording, the disk is read and an RF signal waveform is observed (see FIG. 17). Then, the optimum recording position is obtained from the phase difference between the center of the 14T part and the center of the mirror part of the RF signal (when the 14T center coincides with the mirror part center, the recording start position is in an optimum state). Thereafter, the recording start position setting parameter (hereinafter referred to as timeset; see FIG. 18) P1, P2, or P3 is set and adjusted according to the phase difference. That is, even if a phase delay occurs in the wobble signal, the recording start position can be optimized by adjusting the timeset.

JP 2000-173055 A

  However, in the case of Patent Document 1, it can be applied only to an optical disc that already has a recording portion. Also, it is good for an optical disc recorded at the correct recording start position, but in the case of an optical disc having a recording part that is not recorded at the correct recording start position, recording may start from the wrong recording start position. become.

  In the latter case, the adjustment method has to use a special disk, which increases the cost. Further, since it is necessary to actually record on a disk and actually reproduce it to check the state of the RF signal, the time required for the adjustment is greatly increased.

  Also, regarding the inside of the filter circuit, for example, if the phase relationship between the analog wobble signal and the digital wobble signal also varies due to variations in the cut-off frequency fc of the LPF, multiplication processing or the like does not work. Appropriate ADIP information cannot be obtained. As a result, the address information and the synchronization signal are also adversely affected.

  An object of the present invention is to provide an adjusting device and an adjusting method for an optical disc apparatus, which can reduce the cost and time relatively and prevent the adverse effect due to the phase shift in the filter circuit.

More specifically, without being affected by the phase shift of the filter circuit, setting the recording start position to the optimum position, or manufacturing method of the optical disk device can obtain the ADIP information optimally And a phase difference adjusting method and an adjusting apparatus.

According to the first aspect of the present invention, light is irradiated to an information recording medium having an information track wobbled at a constant period, light reflected by the information recording medium is received, and a light reception signal corresponding to the amount of light received is output. An optical pickup, a first filter circuit for removing noise from the wobble signal based on the wobbling of the information track included in the light reception signal , and a fundamental frequency component of the wobble signal based on the wobbling of the information track from the light reception signal A second filter circuit for extracting a nearby frequency component; a multiplier for multiplying a signal output from the first filter circuit by a signal output from the second filter circuit; and an input to the multiplier Included in the wobble signal based on a phase adjustment circuit for adjusting a phase difference between the two signals and an output signal from the multiplier. A method of manufacturing an optical disc device comprising an information detection circuit for detecting information, the test signal having the same period as the fundamental frequency component of the wobble signal extracted at the time of information recording being the first filter circuit and the second filter A phase difference acquisition step of acquiring a phase difference between the test signal output from the first filter circuit and the test signal output from the second filter circuit, and the phase difference Adjusting the phase difference between the two signals input to the multiplier by the phase adjustment circuit based on the phase difference acquired by the acquisition step.

  According to a second aspect of the present invention, in the method of manufacturing an optical disc device according to the first aspect, the phase difference obtaining step is inputted to the test signal outputted from the first filter circuit and the first filter circuit. A first phase difference obtaining step for obtaining a phase difference from the previous test signal; and a phase difference between the test signal output from the second filter circuit and the previous test signal input to the second filter circuit. And a second phase difference acquisition step of acquiring.

According to the third aspect of the present invention, light is irradiated onto an information recording medium having an information track wobbled at a constant period, light reflected by the information recording medium is received, and a light reception signal corresponding to the amount of light received is output. An optical pickup, a first filter circuit for removing noise from the wobble signal based on the wobbling of the information track included in the light reception signal , and a fundamental frequency component of the wobble signal based on the wobbling of the information track from the light reception signal A second filter circuit for extracting a nearby frequency component; a multiplier for multiplying a signal output from the first filter circuit by a signal output from the second filter circuit; and an input to the multiplier Included in the wobble signal based on a phase adjustment circuit for adjusting a phase difference between the two signals and an output signal from the multiplier. A phase difference adjusting method for adjusting the phase difference in the optical disc apparatus comprising: a data detecting circuit for detecting the information, wherein the test signal of the fundamental frequency component of the same period of the wobble signal extracted during the recording of information a A step of inputting to the first filter circuit and the second filter circuit, and obtaining a phase difference between the test signal output from the first filter circuit and the test signal output from the second filter circuit. A phase difference acquisition step, and a step of adjusting a phase difference between the two signals input to the multiplier by the phase adjustment circuit based on the phase difference acquired by the phase difference acquisition step.

According to a fourth aspect of the present invention, in the phase difference adjusting method according to the third aspect, the phase difference obtaining step is performed before the test signal output from the first filter circuit and the first filter circuit are input. A phase difference between a first phase difference acquisition step of acquiring a phase difference from the test signal of the second test circuit, a test signal output from the second filter circuit and a test signal before input to the second filter circuit. A second phase difference obtaining step to obtain.

The invention according to claim 5 irradiates light to an information recording medium having an information track wobbled at a constant period, receives light reflected by the information recording medium, and outputs a light reception signal corresponding to the amount of light received. A first filter circuit for removing noise from a wobble signal based on the wobbling of the information track included in the light reception signal, and a vicinity of a fundamental frequency component of the wobble signal based on the wobbling of the information track from the light reception signal. A second filter circuit for extracting a frequency component of the signal, a multiplier for multiplying the signal output from the first filter circuit and the signal output from the second filter circuit, and an input to the multiplier Included in the wobble signal based on the phase adjustment circuit for adjusting the phase difference between the two signals and the output signal from the multiplier A phase difference adjustment device for adjusting the phase difference in an optical disc apparatus comprising an information detection circuit for detecting information, wherein the test signal having the same cycle as the fundamental frequency component of the wobble signal extracted at the time of information recording is Means for inputting to the first filter circuit and the second filter circuit, and a phase difference between the test signal output from the first filter circuit and the test signal output from the second filter circuit; Phase difference acquisition means , and means for adjusting the phase difference between the two signals input to the multiplier by the phase adjustment circuit based on the phase difference acquired by the phase difference acquisition means .

According to a sixth aspect of the present invention, in the phase difference adjusting device according to the fifth aspect, the phase difference acquisition unit is configured to input the test signal output from the first filter circuit and the first filter circuit. A first phase difference acquisition means for acquiring a phase difference between the test signal and a test signal output from the second filter circuit and a phase difference between the test signal before input to the second filter circuit; Second phase difference acquisition means for acquiring.

  According to the present invention, cost and time can be relatively reduced, and adverse effects due to phase shift in the filter circuit can be prevented.

The best mode for carrying out the method of manufacturing an optical disk device according to the present invention will be described with reference to the drawings. As this embodiment, an example of application to an optical disc apparatus provided with a wobble signal detection circuit for an optical disc (information recording medium) 1 such as a DVD + RW capable of recording information will be described. Further, as shown in FIG. 1A, the optical disc 1 has an information track 2 wobbling (meandering) at a constant cycle, and the information track 2 is a phase modulation system as shown in FIG. 1B. The one formed in advance on the substrate of the optical disk 1 by (PSK method = Phase Shift Keying) is used. In FIG. 1A, the black portion is an example of the recording mark 3.

  FIG. 2 is a schematic diagram showing a configuration example of the optical disc apparatus 10 of the present embodiment provided with a wobble signal detection circuit. The optical disk apparatus 10 includes a spindle motor 11 for rotating the optical disk 1, an optical pickup apparatus 12, a laser control circuit 13, an encoder 14, a motor driver 15, an analog signal processing circuit 16, a decoder 17, a servo controller 18, and a buffer RAM 19. , D / A converter 20, buffer manager 21, interface 22, ROM 23, CPU 24, RAM 25, and the like. Note that the arrows shown in FIG. 2 indicate the flow of typical signals and information, and do not represent the entire connection relationship of each block.

  The optical pickup device 12 includes a semiconductor laser as a light source, an optical system that guides a light beam emitted from the semiconductor laser to a recording surface of the optical disc 1 and guides a return light beam reflected by the recording surface to a predetermined light receiving position. A light receiving device arranged at a position for receiving the return light beam and a ° drive system (focusing actuator, tracking actuator, seek motor, etc.) (all not shown) are incorporated.

  As shown in FIG. 3A, the light receiver in the optical pickup device 12 includes, for example, a four-divided light receiving element 30 (first to fourth light receiving elements 30a to 30d). In FIG. 3A, for the sake of convenience, the vertical direction of the paper is the X axis direction, the horizontal direction of the paper is the Y axis direction, and the vertical direction of the paper is the Z axis direction. Each of the first and second light receiving elements 30a and 30b has the same rectangular shape having a long side in the horizontal direction (Y-axis direction) in FIG. 3A and the vertical direction (X-axis direction). It is arranged adjacent to. Each of the third and fourth light receiving elements 30c and 30d has the same rectangular shape with the long side in the vertical direction (X-axis direction) in FIG. 3A and the horizontal direction in the paper (Y-axis). In the direction).

  As shown in FIG. 3B, the reflected light RB from the recording surface of the optical disc 1 is branched in two directions by the prism 31 constituting the optical system of the optical pickup device 12, and is one reflected light that has passed through the prism 31. RB1 is applied to the first and second light receiving elements 30a and 30b. The other reflected light RB2 branched in the −X axis direction by the prism 31 is further bent in the traveling direction in the + Z direction by the reflecting mirror 32, and is irradiated to the third and fourth light receiving elements 30c and 30d.

  Here, as shown in FIG. 4A, among the reflected light RB, the reflected light RBa in the upper half of the paper surface in FIG. 4A is irradiated to the first light receiving element 30a, and the reflected light in the lower half of the paper surface. RBb is applied to the second light receiving element 30b. 4B, among the reflected light RB, the reflected light RBc in the right half of the paper surface in FIG. 4B is irradiated to the third light receiving element 30c, and the reflected light RBd in the left half of the paper surface is reflected. Irradiates the fourth light receiving element 30d. Each of the first to fourth light receiving elements 30a to 30d performs photoelectric conversion and outputs a current (current signal) corresponding to the amount of received light to the analog signal processing circuit 16 as a photoelectric conversion signal.

  The light receiver is not limited to the four-divided light receiving element 30, and includes, for example, a two-divided light receiving element configuration including the first and second light receiving elements 30a and 30b, and the third and fourth light receiving elements 30c and 30d. It may be a two-part light receiving element configuration or the like, or may be a configuration in which the first to fourth light receiving elements 30a to 30d are arranged in a line, and is arbitrary including shape, arrangement, and the like.

Returning to FIG. 2 , the analog signal processing circuit 16 includes an I / V amplifier (current-voltage conversion amplifier) 26 that converts a current signal, which is an output signal of the light receiving elements 30 a to 30 d of the optical pickup device 12, into a voltage signal, a wobble signal. A wobble signal detection circuit 27 for detecting the reproduction signal, an RF signal detection circuit 28 for detecting an RF signal including reproduction information, an error signal detection circuit 29 for detecting a focus error signal and a track error signal, and the like.

  As shown in FIG. 5, the I / V amplifier 26 includes I / V amplifiers 26 a to 26 d that convert current signals from the first to fourth light receiving elements 30 a to 30 d into voltage signals (signals Sa to Sd). ing.

  Further, the RF signal detection circuit 28 adds all these voltage signals Sa to Sd, further binarizes the addition result, and detects it as an RF signal.

  The error signal detection circuit 29 obtains the difference between the voltage signals Ra and Rb, binarizes the result, detects it as a focus error signal, obtains the difference between the voltage signals Rc and Rd, binarizes the result, and tracks error. Detect as a signal. These focus error signal and track error signal detected here are output from the error signal detection circuit 29 to the servo controller 18, respectively.

  The wobble signal detection circuit 27 detects a wobble signal based on the voltage signals Sc and Sd and outputs the wobble signal to the decoder 17. The configuration of the wobble signal detection circuit 27 will be described later.

  In the decoder 17, address information, a synchronization signal, and the like are extracted from ADIP information included in the wobble signal detected by the wobble signal detection circuit 27. The address information extracted here is output to the CPU 24, and the synchronization signal is output to the encoder 14.

  The decoder 17 also performs reproduction processing such as demodulation and error correction processing on the RF signal detected by the RF signal detection circuit 28. Further, when the reproduction data is other than music data (for example, image data, document data, etc.), the decoder 17 performs error check and error correction processing based on the check code added to the data, and passes through the buffer manager 21. And stored in the buffer RAM 19.

  The servo controller 18 creates a control signal for controlling the focusing actuator of the optical pickup device 12 based on the focus error signal detected by the error signal detection circuit 29 and outputs the control signal to the motor driver 15. The servo controller 18 creates a control signal for controlling the tracking actuator of the optical pickup device 12 based on the track error signal detected by the error signal detection circuit 29 and outputs the control signal to the motor driver 15.

In D / A converter 20, data recorded on the optical disc 1 is in the case of music data, converts the output signal of the decoder 17 into analog data, and outputs to the audio equipment or the like and an audio signal.

  The buffer manager 21 manages the accumulation of data in the buffer RAM 19, and notifies the CPU 24 when the accumulated data amount reaches a predetermined value.

  The motor driver 15 drives the focusing actuator and tracking actuator of the optical pickup device 12 based on the control signal from the servo controller 18. Further, the motor driver 15 controls the spindle motor 11 based on an instruction from the CPU 24 so that the optical disc 1 has a constant linear velocity (CLV method) or a constant rotation speed (CAV method). Further, the motor driver 15 drives a seek motor based on an instruction from the CPU 24 to control the position of the optical pickup device 12 in the sledge direction (radial direction of the optical disc 1).

  In the encoder 14, an error correction code is added to the data stored in the buffer RAM 19 to create write data to the optical disk 1. Based on the instruction from the CPU 24, the write data is output to the laser control circuit 13 in synchronization with the synchronization signal from the decoder 17.

  The laser control circuit 13 controls the output of the semiconductor laser in the optical pickup device 12 based on the write data from the encoder 14. The laser control circuit 13 outputs a timing signal synchronized with the mark recording period and the space recording period to the wobble signal detection circuit 27 during recording.

  The interface 22 is a bidirectional communication interface with a host (for example, a personal computer), and conforms to a standard interface such as ATAPI (At Attachment Packet Interface), SCSI (Small Computer System Interface).

  The CPU 24 controls the operation of each unit as described above according to the program stored in the ROM 23 and temporarily stores data necessary for the control in the RAM 25.

  Next, a configuration example of the wobble signal detection circuit 27 and its output side will be described with reference to FIG. First, sample and hold circuits (S / H) 41a and 41b to which voltage signals Sc and Sd from the I / V amplifiers 26c and 26d are inputted are provided, and the S / H 41a and 41b output side after the sample hold. A balance AGC 42 is provided to balance the amplitudes of the voltage signals Sc and Sd. On the output side of the balance AGC 42, there is provided a subtractor 43 for calculating a difference Sc-Sd between the voltage signals Sc and Sd after the sample and hold. A filter circuit 44 is provided on the output side of the subtracter 43. The filter circuit 44 includes a BPF path for a digital wobble signal by a BPF (band pass filter) 45, and an HPF + LPF path for an analog wobble signal by an HPF (high pass filter) 46 and an LPF (low pass filter) 47. Consists of. The frequency band that the BPF 45 allows to pass is the frequency of the carrier wave of the wobble signal (the part other than the phase modulation part in the wobble signal), that is, a limited frequency band near the fundamental frequency of the wobble signal. Therefore, the phase modulation component and noise are reduced from the wobble signal by the BPF 45, and it becomes easy to create a signal corresponding to the carrier component of the wobble signal. The signal corresponding to the carrier wave component has a constant frequency when the optical disk 1 is rotated by the CLV method. On the other hand, the signal that has passed through the HPF 46 and the LPF 47 becomes a wobble signal from which a high-frequency noise component and a low-frequency noise component have been removed. Note that the HPF 46 may be omitted when noise can be removed to an allowable range for acquiring ADIP information only by the LPF 47. On the output side of the BPF 45, for example, a binarizer 48 using a comparator is provided.

  For the digital wobble signal obtained from the binarizer 48, a PLL circuit 49 for stabilizing the cycle and a delay circuit (delay) 50, which is a phase adjustment circuit for timing adjustment, are provided in order. A sine wave generation circuit 51 that generates a sine wave having the same phase as the digital wobble signal is provided.

  On the other hand, an A / D converter 52 for converting an analog wobble signal obtained from the LPF 47 into digital data is provided. A multiplier 53 for multiplying the analog wobble signal A / D converted by the A / D converter 52 and the digital wobble signal converted into a sine wave is provided. An integrator 54 for integrating the multiplication result is provided on the output side of the multiplier 53. The integrator 54 is set to be reset in units of one wobble period by a reset signal from the timing circuit 55 that generates and outputs a timing signal synchronized with the output of the PLL circuit 49 (output of the delay circuit 50).

  An ADIP information detector 57 is provided on the output side of the integrator 54 via a sample hold circuit (S / H) 56.

  A decoder 17 is connected to the ADIP information detector 57. The decoder 17 detects a synchronization signal ADIPsync based on ADIP information (detects phase modulation of the wobble signal), an error correction unit 62 that performs error correction processing, and address information based on ADIP information after error correction. And an address information extraction unit 63 for extraction.

  The synchronization signal ADIPsync detected by the synchronization detector 61 passes through the delay circuit 64 that is a phase adjustment circuit that outputs the input signal with the phase shifted, and is then input to the encoder 14 to be a write timing signal (recording start timing signal). It is used for the generation of The encoder 14 also receives a write command (or read command) from the CPU 24 at a predetermined timing, and the laser control circuit 13 starts a recording operation when a write timing signal is generated in the presence of the write command. Is set to

  In such a configuration, an outline of a signal processing example in the vicinity of the wobble signal detection circuit 27 will be described with reference to a waveform diagram shown in FIG. First, the voltage signals Sc and Sd, which are the outputs of the I / V amplifiers 26c and 26d, are sampled and held by the S / H 41a and 41b, the amplitude balance after the sample and hold is taken by the balance AGC 42, and the subtractor 43 sets the Sc (S / S / S). After H) -Sd (after S / H) is performed. Since the wobble signal WBL = S1 (see FIG. 7A) on the optical disc 1 cannot actually be grasped as it is, the amplitude balance and the Sc (after S / H) -Sd ( (After S / H) is set to the wobble signal WBL = S1 on the medium. The wobble signal WBL = S1 is input to the filter circuit 44. On the other hand, an analog wobble signal S2 as shown in FIG. 7B is generated through the path between the HPF 46 and the LPF 47, and on the other hand, the BPF 45 By passing through the path, a wobble signal S3 for generating a signal having a fundamental frequency component as shown in FIG. 7C is generated, and further binarized by passing through the binarizer 48. A digital wobble signal S4 as shown in FIG. 7D is generated.

  This digital wobble signal S4 passes through a PLL circuit 49 for generating a signal having a stable predetermined cycle, is delayed by dlyclock by a delay circuit 50, and a digital wobble signal S5 as shown in FIG. Is input to the sin wave generation circuit 51. The sin wave generating circuit 51 generates a sin wave S6 having the same phase as the digital wobble signal S5 as shown in FIG.

  The analog wobble signal S2 A / D converted by the A / D converter 52 and the digital wobble signal converted to the sin wave S6 are multiplied by the multiplier 53, and the multiplication result as shown in FIG. The signal S7 is integrated by the integrator 54 to obtain an integration result signal S8 as shown in FIG. The integration result signal S8 is sampled and held by the S / H 56 and input to the ADIP information detector 57 as a signal S9 as shown in FIG. The ADIP information detector 57 detects ADIP information S10 including address information and a synchronization signal as shown in FIG. 7 (j) based on the signal S9. In the decoder 17 to which the ADIP information S10 is input, the synchronization detector 61 outputs an ADIP synchronization signal ADIPsync = S11 as shown in FIG. 7 (k). The ADIP synchronization signal ADIPsync = S11 passes through the delay circuit 64, which is a phase adjustment circuit that shifts the phase of the input signal and then outputs the ADIP synchronization signal ADIPsync = S12, and is input to the encoder 14. The encoder 14 creates a write timing signal S13 based on the ADIP synchronization signal ADIPsync = S12, and starts recording by the laser control circuit 13 under an AND condition with the write command S14 from the CPU 24.

  It is assumed that a certain time interval e is taken between the synchronization signal ADIPsync and the write timing signal (for example, 16 wbl cycle = 32T × 15). In addition, the synchronization signal ADIPsync and the write timing signal are L → H → L once every ADIP time (= 93 wbl cycle = 32T × 93), and the phase modulation unit at the head of 1 ADIP time becomes H. (Referred to as # 0 shown in FIG. 7).

  In such an operation, before the filter processing by the filter circuit 44, that is, at the time of the signal S1, there is no phase shift that affects the phase demodulation or the like. However, after the filter processing by the filter circuit 44, for example, due to variations in the cut-off frequency fc of the LPF 47 unit, a shift occurs in the phase of the analog wobble signal, and a shift occurs in the generation timing of the write timing signal S13. There is a possibility that the recording start position will deviate from the optimum position. In FIG. 7B, “a” represents a phase delay caused by the LPF 47.

Therefore, in the first reference example , an adjustment function for optimally adjusting the deviation of the recording start position is added in the manufacturing stage or maintenance of the optical disc apparatus. Referring to FIG. 8 which shows a part of the wobble signal detection circuit 27, in the first reference example , the amplitude and frequency are changed to the input side of the filter circuit 44 when the information is recorded instead of the wobble signal S1. A sin wave S21 is input as an alternative signal (test signal) corresponding to the corresponding wobble signal S1, for example, from an oscillator (alternative signal input means) 71, and the filter circuit 44 at that time, here, the input / output of the path between the HPF 46 and the LPF 47 The phase difference between the front and rear signals is measured by observation with an oscilloscope (phase difference detection means) 72, for example. The phase difference detected here corresponds to the phase delay a shown in FIG.

  On the other hand, in the optical disc apparatus 10, a delay circuit (delay) 64 for appropriately adjusting the phase of the synchronization signal ADIPsync = S11 that affects the timing of the write timing signal S13 is provided between the synchronization detector 61 and the encoder 14. The delay circuit 64 is configured such that the phase can be arbitrarily adjusted by setting the delay time timeset (recording start position setting parameter). Here, there is a proportional relationship as shown in FIG. 9 between the phase difference between the input / output signals on the path of the HPF 46 and the LPF 47 and the delay time timeset. Note that the proportional relationship shown in FIG. 9 can be easily created, for example, by recording a mirror disk in increments of 1 ECC while changing the timeset, and reproducing the portion. The timing of the write timing signal S13 can be optimized by obtaining in advance and adjusting the delay time timeset of the delay circuit 64 in accordance with the phase difference detected by the oscilloscope (phase difference detecting means) 72.

Here, details of the adjustment setting of the recording timing based on the detected phase difference will be described with reference to FIG. 10, which is an excerpt of FIG. FIG. 10 is a waveform diagram showing the relationship between the phase delay a in the path between the HPF 46 and the LPF 47 in the filter circuit 44, the delay amount d by the delay circuit 64, and the write timing signal S13. First, the phase of the synchronization signal ADIPsync = S11 by the synchronization detector 61 is delayed by the amount of delay of the phase of the analog wobble signal S2 in the path between the HPF 46 and the LPF 47 = phase delay a. Then, the phase of the synchronization signal ADIPsync = S12 after the delay processing by the delay circuit 64 is delayed by the delay amount d in timeset. Further, it is assumed that the phase relationship between the synchronization signal ADIPsync = S12 and the write timing signal S13 has a difference of a constant interval e. Further, according to the standard, the wobble signal wbl is one block in 93 cycles, and the write start timing is wbl # 14 + 24T (wbl # 14 is a signal in the 15th cycle counted from the phase modulation unit wbl # 0, 1 wobble cycle = 32T). It is stipulated to bring it to the position. Here, 24T is 1T × 24 of the RF signal. For example, if the disk rotation speed is equivalent to 1 time, 1T≈38.5 ns, and if it is equivalent to 2 times, 1T≈19.2 ns, equivalent to 4 times. For example, 1T ≒ 9.6ns, ... As shown in FIG. 7, since the detected wobble signal is delayed by about one cycle with respect to the actual wobble signal on the optical disc 1, recording starts on the optical disc 1 from the position of approximately wbl # 15 + 24T. (# 15 in Fig. 16 etc. means this).

in this case,
a + d + e = wbl16 cycle + 24bit
= 16 × 32T + 24T
If this holds, the write timing signal is in accordance with the standard. Therefore,
d = 16 × 32T + 24T−ae
The delay time timeset may be adjusted and set so that

As described above, according to the first reference example, the sinusoidal wave S21 having an amplitude and frequency corresponding to the wobble signal is input to the optical disc apparatus 10 on the input side of the filter circuit 44 by the oscillator 71, and the HPF 46 and the LPF 47 at that time By detecting the phase difference between the signals before and after the input / output of the path with the oscilloscope 72 and adjusting and setting the delay time timeset of the delay circuit 64 according to the detected phase difference, the timing of the write timing signal is optimal. Thus, the recording start position can be optimized easily and appropriately without actually performing the recording / reproducing operation for each optical disc apparatus 10. For this purpose, it can be realized simply by using the oscillator 71 and the oscilloscope 72.

As another reference example 2 , in place of the oscillator 71 and the oscilloscope 72, although not particularly illustrated, a gain phase analyzer may be used as an alternative signal input unit and a phase difference detection unit. That is, a gain phase analyzer inputs a sin wave having an amplitude corresponding to a wobble signal as an alternative signal to the input side of the filter circuit 44 while sweeping the frequency, and measures the frequency characteristics of the output with respect to the input of the HPF 46 + LPF 47. The frequency characteristics in this case are “horizontal axis; frequency, vertical axis; gain and phase”. Then, the phase lag when the frequency is equivalent to the wobble signal is obtained, and this phase lag may be set as a described above.

  Thus, when using a gain phase analyzer, it can carry out easily and also can test | inspect the characteristic of HPF46 + LPF47.

Further, the in Reference Example 2, an oscilloscope 72 and a gain phase analyzer was to detect the phase difference between the input and output signals before and after the HPF46 + LPF47 path, as one alternative of Reference Example 3, input and output before and after BPF45 The delay amount timeset of the delay circuit 64 may be adjusted and set according to the detected phase difference. In this case, the phase of the analog wobble signal is adjusted in accordance with the phase of the digital wobble signal.

Further, in the present reference example 3 , the phase difference between the signals before and after the input / output of the filter circuit 44 is directly detected. However, as another reference example 4 , for example, as shown in FIG. The amplitude ratio a ′ (= output amplitude of the HPF46 + LPF47 path / input amplitude of the HPF46 + LPF47 path) before and after the input / output of the HPF46 + LPF47 path when an alternative signal such as the wave S21 is input is an amplitude comparator (amplitude ratio detecting means) 74. The phase difference (phase lag) a is detected by the phase difference detector (phase difference detecting means) 75 based on the amplitude ratio a ′, and the delay time time set of the delay circuit 64 is adjusted and set. Good. In this case, the filter characteristic of the LPF 47 is measured in advance, and the relationship between the amplitude ratio and the phase delay corresponding to the filter characteristic is written in the control program, and the phase difference detector 75 uses this relationship to obtain the amplitude ratio a What is necessary is just to obtain | require the phase difference a from '.

The implementation of the embodiment of the present invention will be described with reference to FIGS. 12 and 13. In the present embodiment, an adjustment function is added to the optical disc apparatus 10 so as to eliminate the poor demodulation characteristics of ADIP information caused by the phase shift at the manufacturing stage or maintenance of the optical disc apparatus. . In FIG. 12, only the relevant portion in the wobble signal detection circuit 27 is extracted and shown.

  In the present embodiment, instead of the wobble signal S1, the sin wave S21 is used as an alternative signal (test signal) corresponding to the wobble signal S1 corresponding to the amplitude and frequency when recording information, instead of the wobble signal S1. For example, the signal is input from an oscillator (alternative signal input means) 71, and the phase difference a between the signals before and after the HPF 46 + LPF 47 path at that time is measured by, for example, observation with an oscilloscope (phase difference detection means) 72, and signals before and after the input / output of the BPF 45 path The phase difference b is measured by observation with an oscilloscope (phase difference detection means) 72, for example, and a delay as an adjustment means provided at the subsequent stage of the PLL circuit 49 so that the phases of both paths match based on these measurement results. The delay time dlyclock of the circuit 50 is adjusted and set.

  FIG. 13 is a waveform showing the relationship between the phase of the wobble signal S1 before filtering, the phase of the analog wobble signal S2 that has passed through the LPF 47, and the phase of the digital wobble signal S3 that has passed through the BPF 45 (before digitization by the binarization circuit 48). FIG. In the HPF46 + LPF47 path, the phase of the analog wobble signal S2 is delayed by a. In the BPF45 path, the phase of the digital wobble signal S3 is delayed by b. Then, before a sin wave digital wobble signal is generated by the sin wave generating circuit 51, a phase delay corresponding to c can be provided by the delay time dlyclock set in the delay circuit 50 (see FIG. 7 and the like). Here, at the time of ADIP demodulation, since the sin wave = S6 and the analog wobble signal S2 are multiplied by the multiplier 53, the higher the amplitude after multiplication, the more the ADIP information can be demodulated. For that purpose, it is necessary that the phase relationship between the sin wave and the analog wobble signal is the same phase.

Therefore,
a = b + c
When the above holds, the phase relationship between the analog wobble signal and the digital wobble signal becomes the same phase, and the most accurate ADIP demodulation is possible. Therefore, based on the measurement results,
c = a−b
Thus, the delay time dlyclock of the delay circuit 50 can be adjusted and set.

  As described above, according to the present embodiment, the sinusoidal wave S21 having an amplitude and frequency equivalent to the wobble signal is input to the optical disc apparatus 10 on the input side of the filter circuit 44 by the oscillator 71, and the HPF 46 and the LPF 47 at that time The oscilloscope 72 detects the phase difference between the signals before and after the input / output of each path and the phase difference between the paths of the BPF 45, and the delay time of the delay circuit 50 so that the phases of both paths become the same phase based on the detected phase difference. Since the ADIP demodulation can be optimally performed by adjusting and setting the dlyclock, the ADIP demodulation is always performed with the optimal delay time dlyclock without actually performing the recording / reproducing operation for each optical disc apparatus 10. be able to. For this purpose, it can be realized simply by using the oscillator 71 and the oscilloscope 72.

  Also in this case, a gain phase analyzer may be used in place of the oscillator 71 and the oscilloscope 72. Further, according to the example shown in FIG. 11, the amplitude ratio of the signals before and after the input / output of the filter circuit 44 is detected in each path, and each phase difference is detected based on the detected amplitude ratio. Based on the above, the delay time dlyclock of the delay circuit 50 may be adjusted and set as described above.

In the present embodiment, the output signal of the BPF 45 is delayed from the delay circuit 50. However, instead of or in addition to such a configuration, the output signal of the LPF 47 is input to the phase adjustment circuit. The phase may be adjusted. FIG. 19 shows a flowchart relating to a method of manufacturing the optical disc apparatus 10 including the step of adjusting the delay times of the delay circuit 50 and the delay circuit 64. In this manufacturing process, as an assembly process, first, components such as the filter circuit 44, the multiplier 53, the delay circuits 50 and 64, the ADIP information detector 57, the synchronization detector 61, and the encoder 4 are provided in a housing (not shown). (S101). When one assembly is completed, the next step is an adjustment process for adjusting the assembled parts. Here, the delay time adjustment process according to the present invention will be mainly described. The test signal as described above is input to the BPF 45 and HPF 46 which are the filter circuits 44 (S102). In a state in which inputs a test signal, to detect and measure the phase difference a between the test signal outputted from the test signal and the LPF 4 7 inputted to HPF46 (S103). Further, the phase difference b between the test signal input to the BPF 45 and the test signal output from the BPF 45 is measured and detected (S104). The measurement / detection method of these phase differences is as described above. Then, the delay circuit 64 is adjusted by the delay time timeset corresponding to the phase difference a (or phase difference b) (S105). Thereby, it is possible to adjust the deviation of the recording timing. Further, the delay time dlyclock of the delay circuit 50 is adjusted so as to generate a phase difference corresponding to (phase difference a−phase difference b) (S106). Thereby, ADIP information can be acquired correctly.

  Other adjustments such as adjustment of the emission power of the semiconductor laser (gain adjustment) are also performed in the adjustment process.

  When the adjustment process is completed, an inspection process is performed, and various known inspections are performed as to whether or not the optical disc apparatus 10 operates properly. By completing this inspection process, the manufacture of the optical disk device 10 is also completed.

In the case where not adjusted delay time of the delay circuit 64 can be omitted the process of step S105. Further, instead of the processing in step S106, it obtains a phase difference between the output signals of BPF45 the LPF 4 7, may be to adjust the delay time dlyclock of this phase difference by the delay circuit 50.

  When the phase delay due to the BPF 45 is b, in FIG. 7 and the like, an example in which the phase delay a on the LPF 47 side is larger than the phase delay b is shown, but not limited thereto, the BPF 45, HPF 46, and LPF 47 Depending on the characteristics, the reverse, that is, the phase delay b may be larger than the phase delay a. In such a case, it is only necessary to shift the phase of the digital wobble signal S4 by a phase delay where c = b−a (that is, a phase advance in this case).

  In the above description, the example in which the delay time is adjusted manually by using the oscilloscope 72 or the gain phase analyzer has been described. However, the present invention is not limited to this method. That is, as shown in FIG. 20, an oscillator 81 for outputting a test signal, an oscilloscope 72, and the like, a phase difference detection device 82 having a phase difference detection function, and a CPU 83 and a CPU 83 for controlling these, a predetermined control process. It is also possible to configure a dedicated adjustment machine 80 that is combined with a ROM 84 that stores a program for executing the above, and to automatically adjust the delay time of the delay circuit 50 or 64 according to the detected phase difference. Alternatively, a combination of an oscillator 81 that outputs a test signal, a phase difference detection device 82 including an amplitude comparator 74 and a phase detector 75, and a CPU 83 that controls these and a ROM 84 that stores a program for causing the CPU 83 to execute predetermined control processing. The adjustment dedicated machine 80 may be configured so that the delay time of the delay circuit 50 or 64 is automatically adjusted according to the detected phase difference. In these cases, the CPU 83 executes instructions and the like for each component corresponding to each process (steps S102 to S106 shown in FIG. 19) that have been performed manually according to a program stored in the ROM 84 of the device. . That is, the CPU 83 gives a command to the oscillator 81 so as to output a predetermined test signal (S102). In response to this, the oscillator 81 outputs a test signal to the filter circuit 44. Next, the CPU 83 issues a command to cause the phase difference detector 82 to detect the phase difference a of the test signal between the input side of the HPF 46 and the output side of the LPF 47 and the phase difference b of the test signal between the input and output of the BPF 45. (S103, S104). The phase difference detection device 82 detects the phase differences a and b in response to this command. The CPU 83 gives the delay time 64 corresponding to the phase difference a (or phase difference b) to the delay circuit 64 (S105). Further, the CPU 83 provides the delay circuit 50 with a delay time dlyclock corresponding to the phase difference corresponding to (phase difference a−phase difference b) (S107). By performing such processing, the influence of the wobble signal phase shift by the filter circuit 44 can be reduced.

In the case where not adjusted delay time of the delay circuit 64, CPU 83 may omit the processing in step S105. Further, CPU 83, instead of the processing in step S106, obtains a phase difference between the output signals of BPF45 the LPF 4 7, may be to adjust the delay time dlyclock of this phase difference by the delay circuit 50 .

It is a schematic explanatory drawing regarding the information track of an optical disk. It is the schematic which shows the structural example of an optical disk apparatus. It is a front view which shows a light receiver structure. It is a side view which shows a light receiver structure. It is a schematic circuit diagram which shows an I / V amplifier structure. It is a block diagram which shows the structural examples, such as a wobble signal detection circuit. It is a wave form diagram which shows the example of the operation signal of each part. It is a schematic block diagram which extracts and shows a part of wobble signal detection circuit. It is a characteristic view which shows the relationship between the phase difference between input-output signals, and delay time. It is a wave form diagram which shows a part of operation signal example. It is a schematic block diagram which shows the structural example of the reference example 4 regarding an alternative signal input means and a phase difference detection means. It is a schematic block diagram which extracts and shows a part of wobble signal detection circuit of embodiment of this invention. It is a wave form diagram which shows the phase relationship between the related signals. It is a schematic block diagram which shows the example of a structure of a part of conventional wobble signal detection circuit. It is a wave form diagram which shows the signal characteristic according to the dispersion | variation in the cut-off frequency fc. It is explanatory drawing which shows a mode that a recording start position shifts. It is explanatory drawing which shows the mode of RF signal waveform. It is a wave form diagram which shows the example of adjustment operation. It is a schematic flowchart which shows the manufacturing method of an optical disk apparatus. It is a schematic block diagram which shows the structural example of an adjustment exclusive machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Information recording medium 2 Information track 10 Optical disk apparatus 44 Filter circuit 45 Band pass filter 46 High pass filter 47 Low pass filter 50 Adjustment means 64 Adjustment means 71 Oscillator, alternative signal input means 72 Oscilloscope, phase difference detection means 74 Amplitude ratio Detection means

Claims (6)

An optical pickup that irradiates an information recording medium having an information track wobbled at a constant period, receives light reflected by the information recording medium, and outputs a light reception signal corresponding to the amount of light received; and the light reception signal And a first filter circuit for removing noise from a wobble signal based on wobbling of the information track, and a frequency component in the vicinity of a fundamental frequency component of the wobble signal based on wobbling of the information track from the received light signal. 2 filter circuit, a multiplier that multiplies the signal output from the first filter circuit and the signal output from the second filter circuit, and a phase difference between the two signals input to the multiplier A phase adjustment circuit for adjusting the information and an information detection for detecting information contained in the wobble signal based on an output signal from the multiplier. A manufacturing method of an optical disk apparatus and a circuit,
Inputting a test signal having the same period as the fundamental frequency component of the wobble signal extracted at the time of information recording to the first filter circuit and the second filter circuit;
A phase difference acquisition step of acquiring a phase difference between the test signal output from the first filter circuit and the test signal output from the second filter circuit;
Adjusting the phase difference between the two signals input to the multiplier by the phase adjustment circuit based on the phase difference acquired by the phase difference acquisition step;
Manufacturing method of an optical disc device including: The phase difference acquisition step includes
A first phase difference acquisition step of acquiring a phase difference between a test signal output from the first filter circuit and a test signal before being input to the first filter circuit;
A second phase difference acquisition step of acquiring a phase difference between the test signal output from the second filter circuit and the test signal before being input to the second filter circuit;
The method of manufacturing an optical disk device according to claim 1 including: An optical pickup that irradiates an information recording medium having an information track wobbled at a constant period, receives light reflected by the information recording medium, and outputs a light reception signal corresponding to the amount of light received; and the light reception signal And a first filter circuit for removing noise from a wobble signal based on wobbling of the information track, and a frequency component in the vicinity of a fundamental frequency component of the wobble signal based on wobbling of the information track from the received light signal. 2 filter circuit, a multiplier that multiplies the signal output from the first filter circuit and the signal output from the second filter circuit, and a phase difference between the two signals input to the multiplier A phase adjustment circuit for adjusting the information and an information detection for detecting information contained in the wobble signal based on an output signal from the multiplier. A phase difference adjusting method for adjusting the phase difference in the optical disc apparatus and a circuit,
Inputting a test signal having the same period as the fundamental frequency component of the wobble signal extracted at the time of information recording to the first filter circuit and the second filter circuit;
A phase difference acquisition step of acquiring a phase difference between the test signal output from the first filter circuit and the test signal output from the second filter circuit;
Adjusting the phase difference between the two signals input to the multiplier by the phase adjustment circuit based on the phase difference acquired by the phase difference acquisition step;
A phase difference adjustment method including: The phase difference acquisition step includes
A first phase difference acquisition step of acquiring a phase difference between a test signal output from the first filter circuit and a test signal before being input to the first filter circuit;
A second phase difference acquisition step of acquiring a phase difference between the test signal output from the second filter circuit and the test signal before being input to the second filter circuit;
The phase difference adjustment method according to claim 3, comprising: An optical pickup that irradiates an information recording medium having an information track wobbled at a constant period, receives light reflected by the information recording medium, and outputs a light reception signal corresponding to the amount of light received; and the light reception signal A first filter circuit that removes noise from a wobble signal based on wobbling of the information track included in the second information signal, and a second frequency component that extracts a frequency component near the fundamental frequency component of the wobble signal based on wobbling of the information track from the received light signal Filter circuit, a multiplier that multiplies the signal output from the first filter circuit and the signal output from the second filter circuit, and a phase difference between the two signals input to the multiplier. Information detection for detecting information contained in the wobble signal based on a phase adjustment circuit for adjustment and an output signal from the multiplier A phase difference adjusting device for adjusting the phase difference in the optical disc apparatus comprising: a road, a
Means for inputting a test signal having the same period as the fundamental frequency component of the wobble signal extracted during information recording to the first filter circuit and the second filter circuit;
Phase difference acquisition means for acquiring a phase difference between the test signal output from the first filter circuit and the test signal output from the second filter circuit;
Means for adjusting the phase difference between two signals input to the multiplier by the phase adjustment circuit based on the phase difference acquired by the phase difference acquisition means ;
A phase difference adjusting device including: The phase difference acquisition means includes
First phase difference acquisition means for acquiring a phase difference between a test signal output from the first filter circuit and a test signal before being input to the first filter circuit;
Second phase difference acquisition means for acquiring a phase difference between the test signal output from the second filter circuit and the test signal before being input to the second filter circuit;
The phase difference adjusting device according to claim 5, comprising:

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