JPS62110632A - Eccentricity correcting device of optical disk - Google Patents

Abstract

PURPOSE:To make eccentricity correction of an unrecorded disk possible by detecting pulse width of tracking error signals of an optical disk, operating eccentricity correction value of the disk from the error signals and a pulse with group and outputting it to an optical head carrying means. CONSTITUTION:A pulse generating means 1 generates pulse synchronously with rotation of an optical disk. Tracking error signals from the optical disk are waveform shaped by a waveform shaping means 2, and output of the means 2 are sent to a pulse width detecting means 3 and pulse width is detected. An arithmetic means 4 operates an eccentricity correction value from the tracking error signals and detected pulse width group. The pulse width group is stored in a storage means 5 and calculated eccentricity correction value is read out by an eccentricity correction value outputting means 7, and sent to an optical head carrying means 8. The means 8 carries the optical head in the direction of tracking according to the eccentricity correction value. Thus, eccentricity correction can be made even for an unrecorded disk.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an eccentricity correcting device for a source disk used for recording and reproducing information.

2. Description of the Related Art In recent years, in the tracking control of the optical head of the original disk, eccentricity correction has been performed to cancel the eccentricity caused by the eccentricity of the disk itself or the misalignment of the center when the disk is installed in a rotating system. (For example, JP-A-57-
(No. 9442) A conventional eccentricity correction device for an optical disk will be described below.

FIG. 6 is a configuration block diagram of a conventional original disk eccentricity correction device, in which 22 is a waveform shaping circuit that shapes a tracking error signal from an optical head (however, the optical head is not shown) into a rectangular wave, and 23 is a waveform shaping circuit. A rising edge detection circuit 24 detects the rising edge of the output signal of the waveform shaping circuit 22 and generates a pulse in response to the rising edge. 26 is a bypass filter that removes unnecessary signals from the reproduced signal from the optical head;
6 is an envelope detection circuit that detects the envelope of the output of the bypass filter 26, and 27 is a high frequency component of the output of the envelope detection circuit 26. a low-pass filter for removing; 28 a waveform circuit for shaping the output of the low-pass filter 27 into a rectangular wave; 29;
30 is an AND circuit that calculates the logical product (ANI) of the output of the rising edge detection circuit 23 and the output of the waveform shaping circuit 28, and 30 is an AND circuit of the outputs of the falling edge detection circuit 24 and the waveform shaping circuit 28.
31 is a rotation angle detection circuit that generates pulses according to the rotation angle of the optical disk; 32 is a counter that outputs the address of the storage circuit by counting the output pulses of the rotation angle detection circuit 31; 33 is an AND circuit that takes D; AND circuit 2
9.30 output? 34 is an up/down counter that goes up or down according to the output of the storage circuit 33; 36 is a D/4 converter that converts the output data of the up/down counter 34 into an analog signal; 36 is a linear motor that moves the optical head using the output of the D/man converter 35.

FIG. 7 shows the waveforms at each point in the configuration of the conventional original disk eccentricity correction device, where (6) is the waveform of the tracking error signal from the optical head, (0 is the output of the waveform shaping circuit 22). The waveform of the signal, (the waveform and width of the output signal of the rising edge detection circuit 23) is the waveform of the output signal of the falling edge detection circuit 24, (i) is the waveform of the reproduced signal of the optical head, and (a) is the bypass filter. The waveform of the output signal of 25, (k
) is the waveform of the output signal of the detection circuit 26, (1) is the waveform of the output signal of the low-pass filter 27, and (m) is the waveform of the waveform shaping path 2.
8, (n) is the waveform of the output signal of AND circuit 29, (0) is the waveform of the output signal of AND circuit 30, (
P) is the waveform of the output signal of the rotation angle detection circuit, and (Q) is the waveform of the rotation reference signal, in which one pulse is generated for one rotation of the original disk.葡) shows the waveform of the output signal of the D/A converter 35.

The operation of the conventional optical disk eccentricity correcting device configured as described above will be described below.

First, the waveform shaping circuit 22 shapes the tracking error signal from the optical head into a rectangular wave (f).

Next, the rising edge of the rectangular wave (0 is detected by the detection circuit 23, the falling edge is detected by the falling detection circuit 24, and the signal (g), (
h).

Next, the reproduced signal (i) of the optical head is passed through the bypass filter 2.
5, unnecessary components are removed to obtain a signal (j), signal CJ) is envelope-detected by a detection circuit 26 to obtain a signal (k), and a signal (
2)) The signal is made into signal (1) by the gellow pass filter 27. Next, the waveform shaping circuit 28 shapes the signal (1) into a rectangular wave to obtain a signal (m). Next, AND circuit 29°3
Person NDi of signal (m), signal (g), (h) by 0
Take.

At this time, when the light spot crosses the trunk from the outer circumferential side to the inner circumferential side, a pulse is generated in the signal (n), and when the light spot crosses the truck from the inner circumferential side to the outer circumferential side, the signal (0) Nihals is generated. Next, the rotation angle detection circuit 31 detects the rotation angle of the original disk, generates a pulse at every predetermined rotation angle, and generates a signal (
p) and counted by the counter 32. Since the counter 32 is cleared by the rotation reference signal (Q), the counter value increases in accordance with the rotation angle of the original disk, and the storage circuit 33
The states of signal (n) and signal (0) are stored in . After the track crossing data for one rotation of the optical disk is stored in the storage circuit 33 as described above, the track crossing data of the storage circuit 33 specified by the output of the counter 32 is inputted to the up/down counter 34, and this up/down counter The value is output by the D/A converter 35 as an analog eccentricity correction signal [F]) to the linear motor 36 for transporting the optical head, and eccentricity is corrected.

Problems to be Solved by the Invention However, in the above-mentioned conventional configuration, eccentricity correction is performed by determining the direction in which the original spot crosses the track using the reproduced waveform of the recorded original disc.
There is a problem in that eccentricity cannot be corrected for disks that have not been subjected to eccentricity correction at all.

Means for Solving the Problem In order to solve this problem, the method for correcting the eccentricity of the original disk according to the present invention generates a reference pulse by a pulse generating means in synchronization with the rotation of the optical disk. A tracking error signal of the disk is made into a pulse wave by a waveform shaping means, a pulse width of )<111 (of the output of the waveform shaping means) is detected by a pulse width detection means, and the pulse width group is stored by a first storage means. Then, the calculating means calculates the eccentricity correction amount and phase of the disk from the tracking error signal and the pulse width group, the calculated eccentricity correction value is stored in the second storage means, and the stored eccentricity correction value is used as the eccentricity correction value. The correction value is inputted to the optical head transporting means through the correction value output means, the optical head is moved in all tracking directions, and if there is a phase shift due to eccentricity correction, the total phase of the eccentricity correction value is 1800.
The configuration is such that the eccentricity is corrected by shifting and re-memorizing it in the second storage circuit to eliminate the phase shift.

Effect With this configuration, the total amount of eccentricity of the original disk is obtained corresponding to the rotation angle, and the eccentricity correction amount is approximated by this, and if there is a phase shift in the obtained eccentricity correction value, the phase of the eccentricity correction value is 11800. Since the phase shift is eliminated by shifting, eccentricity correction can be achieved even on discs on which no recording has been made, and the amount of eccentricity correction can be set in any step width regardless of the track pitch size. .

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic block diagram of the configuration of an eccentricity correction device for an original disk in an embodiment of the present invention, and FIG.

FIG. 3 is a detailed block diagram, FIG. 4 is a waveform diagram of each part, and FIG. 5 is a flow chart of the calculation means.

In FIG. 1, reference numeral 1 indicates a pulse generating means for generating pulses in synchronization with the rotation of the optical disc, 2 indicates a waveform shaping means for shaping the tracking error signal of the optical disc into a pulse wave, and 3 indicates a pulse output from the waveform shaping means 2. 4 is a calculation means for obtaining an eccentricity correction value from the tracking error signal and the pulse width group; 5 is a first storage means for storing the pulse width group; 6 is the calculated a second storage means for storing the eccentricity correction value; 7 is an eccentricity correction value output means for outputting the eccentricity correction value from the second storage means 6 to the optical head transfer means 8; 8 is an eccentricity correction value output means from the eccentricity correction value output means 7; This optical head moving means moves the optical head in the tracking direction according to the eccentricity correction value. Second
3, numeral 9 denotes a first pulse generating circuit that generates one pulse per rotation in synchronization with the rotation of the original disk;
゜ is a waveform shaping circuit that shapes the tracking error signal of the disk into a pulse wave, 11 is a monostable multivibrator that detects the rising edge of the output of the waveform shaping circuit 1o and generates a pulse of a predetermined width, and 12 is a monostable multivibrator. A second pulse generating circuit generates pulses with a constant period at sufficiently shorter intervals than the pulse interval of the output pulses of the vibrator 11, and 13 divides the output pulses of the second pulse generating circuit 12 into pulses of a predetermined frequency. A rotating frequency divider circuit outputs pulse waves of multiple different frequencies. 14 is a first counter that calculates the number of pulses of a pulse wave output of a predetermined frequency of the resenotom frequency divider 13 based on the output of the monostable multivibrator 11; a latch circuit that holds the value of the counter 14; 16 is a second counter that is reset by the output pulse of the first pulse generating circuit 9 and calculates the number of pulses of the pulse wave output of a predetermined frequency of the frequency divider 13; 17 is a microcomputer that calculates the eccentricity correction amount from the output of the latch circuit 16; 17& is a pulse detection means that detects the rise of the output pulse of the first pulse generating circuit 9 and the output pulse of the monostable multivibrator 11; 17b is the latch circuit 1 in response to the pulse detection by the pulse detection means 1
j7c is an eccentricity correction value calculation means that calculates an eccentricity correction value from the data of the data storage means 17b; 17d is an eccentricity correction value calculation means 17c that outputs the eccentricity correction value calculated by Data output means, 1
8 is a data selector that outputs either the output of the second counter 16 or the output data of the microcomputer 17 according to designation; 19 is a memory circuit that sequentially stores and outputs the output of the data selector 18; and 20 is a memory circuit of the memory circuit 19; A D/A converter 21 converts a digital signal into an analog signal, and a near motor moves the optical head in the tracking direction by the output of the D/A converter 20.

In FIG. 4, (a) is the waveform of the output signal of the first pulse generation circuit 9, (b) is the waveform of the tracking error signal that is the output of the optical head input to the waveform shaping circuit 10,
(C) shows the waveform of the output signal of the waveform shaping circuit 1o, and (d) shows the waveform of the output signal of the D/A converter 2o.

The operation of the original disk eccentricity correcting device of this embodiment configured as described above will be described below.

First, the linear motor 21 is servoed by a position sensor.
, and a pulse is detected from the output signal (a) of the first pulse generating circuit 9 by the pulse detecting means 17a. However, the first pulse generating circuit 9 generates one pulse per revolution of the id% disk. Next, the tracking error signal (b) is shaped into a pulse wave by the waveform shaping circuit 10, and the shaped signal (C) is input to the monostable multivibrator 11 and the latch circuit 15. Latch circuit 1
5, the output of the second pulse generation circuit 12 is transmitted to the frequency divider 1.
The first counter 14 receives the signal divided by 3 to a predetermined frequency.
The value counted in is held. However, since the first counter 14 is reset by the output signal of the monostable multivibrator 11 with a predetermined pulse width, the latch circuit 15 includes a frequency divider for the pulse width of the tracking error signal (C). The number of pulses of the output signal of 13 will be maintained. A pulse is detected from the output signal of the monostable multivibrator 11 by the pulse detection means 172L of the microcomputer 17, and the data held by the latch circuit 15 is stored by the data storage output stage 1γb. In this way, the frequency divider 13 between the pulse widths of the tracking error signal (C,)
The operation of storing the number of pulses of the output signal is performed until the first pulse generation circuit 90 detects the next pulse, that is, for one rotation of the disk.

Next, the eccentricity correction value p is determined by the output means 170 by multiplying the number of pulse widths representing the pulse width of the tracking error signal (C) stored in the data storage means 1'7b by the trunk pitch to determine the total eccentricity. The zero eccentricity to find can be approximated by a sine wave at the fundamental frequency. Therefore, by calculating the position of the output signal (a) of the first pulse generating circuit at which the minimum number of pulses is located, the phase of the approximate sine wave can be obtained, and the eccentricity correction value can be calculated. The means 17C determines the phase and calculates approximate sine wave data, that is, an eccentricity correction value.

Next, the data calculated as described above is sequentially stored in the storage circuit 19 via the disk one-time data selector 18. The number of data to be stored is determined by the signal frequency-divided by the frequency divider 13. Next, the second counter 16 specifies the storage circuit 19 via the data selector 18, and the specified eccentricity correction value iD/A converter 2o causes the analog signal (d
) and outputs it to the linear motor 21 to move the optical head in the tracking direction.
is reset by the output of the first pulse generation circuit 9, so the storage circuit 19 starts outputting data from the beginning every time the disk rotates once. Therefore, the linear motor 21 continues to move the optical head in the tracking direction according to the eccentricity correction value.

Next, while the optical head is being moved by the linear motor 21 as described above, the number of pulses of the output signal of the division period 13 corresponding to one revolution of the disk is stored as described above, and the eccentricity correction value calculation means 170 is used. Determine the total eccentricity and adjust the linear motor 21
Compare with the total eccentricity obtained by fixing. linear motor 2
If the amount of low eccentricity is increased compared to the total amount of eccentricity determined by fixing The data of the means 17b is shifted in phase by 1800 degrees and is sequentially stored in the storage circuit 19 via the data selector 18 by the data output means 17d. Then, the eccentricity correction value stored in the storage circuit 19 is output to the linear motor 21 via the D/A converter 20, and the optical head is moved.In this way, the eccentricity can be corrected.

The operation of the microcomputer used in this embodiment will be explained below with reference to the flowchart shown in FIG. All pulses are detected from the output of the stable multivibrator 11 and the data in the latch circuit 16 is stored (step 61). This is repeated until the next output pulse of the first pulse generating circuit 9 is detected, and from the position of the minimum data from the stored data group,
Calculate the phase shift of the approximated sine wave (step 52);
The amplitude of the sine wave is calculated from the number of data copies (step 53). Next, the calculated sine wave data is stored in the storage circuit 19 (step 54), and the D/A converter 20i
The signal is output to the linear motor 21 via the signal line (step 55).

Next, in the same manner as above, memorize the tracking pulse width for one rotation (Step 66),) Find the amplitude of the sine wave from the number of tracking pulses? Calculate (step 57). Next, compare the amplitude of the former sine wave with the amplitude of the latter sine wave (step 58), and if the latter amplitude is larger, shift the phase by 180 degrees (step 59) and calculate the sine wave data. and stored in the memory circuit 19 (step 60), D/
Output to the linear motor 21 via the A converter 20i (step 61) As described above, according to the present embodiment, after measuring and storing the pulse width of the tracking error signal of the optical disk, the eccentricity correction value is determined by arithmetic processing, If there is a phase shift in the obtained eccentricity correction value, by shifting the phase by 1800 to eliminate the phase shift, eccentricity correction can be performed even on the original disc on which no recording has been made.
Furthermore, the eccentricity correction amount can be set in any step width regardless of the size of the track pitch. Furthermore, by using a microcomputer, eccentricity correction can be performed with a simple configuration.

Note that the means for outputting the output of the memory circuit 19 to the linear motor 21 can also be realized using a staircase wave generation circuit in an analog circuit. In this case, the circuit can be constructed at a lower cost.

Effects of the Invention The present invention measures and stores the pulse width of the tracking error signal of the original disk, then calculates the eccentricity correction value through arithmetic processing, and if there is a phase shift in the calculated eccentricity correction value, shifts the phase by 180 degrees. By eliminating the phase shift, it is possible to perform eccentricity correction even on optical discs on which no recording has been made. Furthermore, the eccentricity correction amount can be set in any step width regardless of the track pitch size. Accordingly, it is possible to realize an eccentricity correction device for an optical disk.

[Brief explanation of drawings]

FIG. 1 is a schematic block diagram of the configuration of the original disk eccentricity correction device in an embodiment of the present invention, FIG. 21 is a detailed block diagram of the same, FIG. 4 is a waveform diagram of output signals of each part, and FIG. FIG. 6 is a block diagram showing the configuration of a conventional eccentricity correction device for an optical disk, and FIG. 7 is a waveform diagram of output signals of each part. 1...Pulse generation means, 2...Waveform shaping means, 3...Pulse width detection means, 4...
...Calculating means, 5...First storage means, 6...
. . . Second storage means, 7 . . . Eccentricity correction amount output means, 8 . . . Optical head transport means 0.

Claims (3)

[Claims] (1) Pulse generating means that generates pulses in synchronization with the rotation of the optical disk, waveform shaping means that shapes the tracking error signal of the optical disk into a pulse wave, and a pulse width that detects the pulse width of the output of the waveform shaping means. detection means;
a first storage means for storing the pulse width group; a calculation means for calculating the eccentricity correction amount and phase of the disk from the tracking error signal and the pulse width group; and a second storage means for storing the calculated eccentricity correction value. storage means; optical head transport means for transporting the optical head in the tracking direction in synchronization with the disk based on the stored eccentricity correction value; and eccentricity for outputting the eccentricity correction value from the second storage means to the transport means. 1. An eccentricity correction device for an optical disk, comprising correction value output means. (2) The pulse width detection means includes a clock generation circuit, a counter that counts the number of pulses of the clock, and a latch circuit that holds the value of the counter. Optical disk eccentricity correction device. (3) The calculation means is a microcomputer that eliminates the phase shift by shifting the phase of the eccentricity correction amount by 180 degrees in response to an increase in the amount of eccentricity due to the phase shift of the eccentricity correction. The optical disk eccentricity correcting device according to scope 1.