JPS62248141A - Information recording and reproducing device having plural pickups - Google Patents

Abstract

PURPOSE:To attain stable locking without complicated adjustment by eliminating the effect of eccentricity of an information track before the operation of tracking control. CONSTITUTION:When it is discriminated to be minimum with a phase difference theta2 at the operating period, the signal of a phase difference theta2 is outputted from a D/A converter 14b, and when it is discriminated that the correction signal of a phase difference theta3 is minimum, a correction signal corresponding to the phase difference theta1 from any D/A converter is outputted. When an optimum correction signal is obtained, a microcomputer 8 outputs a TOK signal to the system control for the reproduction.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a recording/reproducing apparatus using a conventional academic method for simultaneously recording or reproducing information such as video gI@ on a disc-shaped recording medium using a plurality of pickups. More specifically, it relates to tracking control.

[Background of the invention]

Generally, in an optical recording/reproducing device, a disk-shaped recording medium is used, and information signals are recorded on the disk-shaped recording medium as spiral or concentric recording loci (hereinafter referred to as tracks). is played from. In such information recording and reproducing devices, for the purpose of achieving a high quality ratio, for example, two recording/Nyu optical heads are used, and a luminance signal that requires a wide band is transmitted to the outer periphery with good frequency characteristics. A method has been considered in which color signals are recorded separately in the inner circumferential area where the stage number characteristics are poor, and during playback, the original video signal is obtained from the signals obtained from each of the two original heads.

Even in recording and reproducing devices of this type, there is a tendency to further increase the density in the future regardless of the recording and reproducing method or means, considering the economic efficiency of recording media and miniaturization of devices, etc., and it is necessary to achieve this. Therefore, as the trap recording wavelength becomes shorter and the length becomes shorter, the demand for narrower tracks is increasing.

One of the problems that arises as a result of this narrowing of the track is that when a recording medium with recorded information tracks is loaded and unloaded from the device and then reattached to the device via W2C, the loaded recording medium may be mechanically misaligned. Distortion of the 1* signal track exceeding the track spacing may occur due to eccentricity due to the recording medium and plastic deformation due to thermal or mechanical stress of the recording medium. Therefore, unless tracking control is performed to follow the distorted shape of the information track, the distorted shape will cause the reproduction scanning position it of the reproduction means (specifically, the position 01 of the optical spot) and the information track to be relative to each other in the direction perpendicular to the track. This results in significant positional fluctuations.

Normally, most of the distortion in information tracks is due to eccentricity, which occurs due to the rotation of the disk-shaped recording medium, and depends on the mounting condition of the disk, etc., its size and the disk-shaped recording medium. This causes a conflict in which the phase with respect to the rotation angle is different.

Distortion of the information track depends on the accuracy of the information reproducing device or the disk-shaped recording medium, but it occurs in the order of tens to hundreds of micrometers, and if the track spacing is about 2-
This is an order of magnitude or two orders of magnitude more regrettable.

Therefore, in a normal reproduction state, tracking control is performed so that the light spot for reproducing the information signal closely follows the distorted shape of the track. The relative positional deviation between the optical spot and the track at this time needs to be kept to an accuracy of about 0.1- or less, taking into account the a stalk from the adjacent track. However, the disk strain, %V
When the component caused by the C center becomes large, the relative positional deviation between the optical spot and the track becomes large, and the problem of glue a stalk from the adjacent track becomes a problem. In order to reduce this positional deviation, it is possible to increase the gain of the tracking control circuit, but if the gain of the control circuit is increased too much, problems such as oscillation of the control circuit will occur, causing the circuit to become unstable. A problem arises.

As a method to counter the above drawbacks, for example, Japanese Patent Laid-Open No. 56-7
247, first, from the tracking error signal obtained when the tracking control circuit is operating normally,
A waveform corresponding to the distortion shape of the information track is extracted and stored once in memory, and then this stored waveform is read out in synchronization with the rotation of the disk, and the signal read out from this menu is sent to the tracking control circuit. There is a method of correcting positional fluctuations and misalignments between the reproduction light spot and the information track by applying the same amount of light to the information track.

This method assumes that the tracking control operates reliably, but if the eccentricity caused by the disk gcN is too large, the tracking control may not be performed due to track distortion. There is a problem in that if the tracking error signal is stored in waveform and then corrected using this stored signal, it will have the opposite effect.

[Purpose of the invention]

An object of the present invention is to provide an information recording and reproducing apparatus having a plurality of pickups as described above, in which the reproducing scanning position of the reproducing means (
It is an object of the present invention to provide a control device which corrects the position of the reproduction light spot IIt) and the relative positional fluctuation of the information track.

[Summary of the invention]

Therefore, in the present invention, we have focused on the fact that the distortion of information tracks caused by the disk device mainly occurs in synchronization with the rotation of the disk. The magnitude and phase of eccentricity are detected from the error signal output of the tracking control circuit provided in each recording/reproducing optical head, and based on this detected information, the memory circuit is controlled to generate the optimal correction signal. We adopted a method that would allow this to occur.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

Here, an example will be explained in which a video signal is separated into a luminance signal and color No. 91, and recorded and reproduced using two optical heads.

FIG.
The optical head 29cL (or optical head 29b) shown in the figure
) is an explanatory diagram showing the configuration of. In the figure, the original beam of a laser diode 16 is converted into parallel light by a collimating lens 17, and then converted into parallel light with an approximately circular cross section by cylindrical lenses 18 and 19. The beam is attached to an actuator 22 through a polarizing beam splitter 20 and a diagonal plate 21. The objective lens 25 focuses the light onto the disk 28 as a light spot.

The reflected light from the disk 28 is converted into parallel light again by the objective lens 25, and after passing through the optical wavelength plate 21.

The beam is reflected by the polarization reflecting surface of the polarizing beam splitter 20 (after passing through the convex lens 24, the beam is split into two by the mirror 25, one of which is sent to two-split light receiving elements 27cL and 27b for detecting focus errors, and the other is sent to detect tracking errors. The light is incident on the two-split light-receiving element 26αs and 26b.

FIG. 3 is a block diagram showing an example of an optical recording/reproducing apparatus to which the present invention is implemented.

In the figure, 28 is a disk, 32 is a photosensor for detecting recording alignment marks, 33 is a waveform shaping circuit, and 50
29 is a disk rotation motor; 51 is a disk motor drive circuit that controls the disk rotation motor 30 so that one rotation of the disk 28 corresponds to one frame of the video signal;
a, 29b are the optical heads shown in FIG. 2, 34α, 3
4b is a carriage equipped with an optical head, 35α, 55h
is a carriage motor 36α for moving the carriage in the radial direction of the disk 2B.

56h is a carriage motor drive circuit, 37α, 37b are 1-V conversion processing circuits, 39 is a tracking control circuit, 4
0 is a reproduction signal processing circuit, 41 is a TV receiver, and 42α.

42.6 is an RF signal detection circuit for detecting the presence or absence of a reproduced RF signal.

43α, 43b are address demodulation circuits, 44 is a keyboard for inputting various command signals, 45 is a system console consisting of a microcomputer, etc.;
46α, 46b are recording control circuits, 47α, 47b are laser drive circuits, 48α, 48b are video signal generation sources, 49α
.

49b is a recording signal processing circuit.

As the video signal generation source 48α, for example, 5 of the video signal
For example, the color signal 48b is a luminance prime signal, and the color signal is recorded in the inner circumferential area of the disk 28 and the luminance signal is recorded in the outer circumferential area of the disk 28 while maintaining a certain distance from each other. belongs to. Since the recording signal processing, the method of dividing the recording area of the disk, etc. are not directly related to this patent, a detailed explanation will be omitted here.

The video signal from the video signal generation source 48α (or 48b) is subjected to CFM modulation to the recording (H number processing circuit 49α (or 49b), and is sent as an RF scratch signal to the laser drive circuit 47.
It is input to α (or 47b). Laser drive circuit 4
7α (or 47b) indicates that the recording/reproduction switching key V1 (or f etc.) from the recording control circuit 46α (or 46b) is Highl to Highk or (or owl to Low level opening head 22α (or 291)).
The output light of the laser equipped with an IfC is intensity-modulated according to the input RF signal and irradiated onto the disk 28.
Information is recorded as changes in the reflectance of laser light from the

Also, during playback, the recording control circuit 46α (or 46k
) (or σ1) is L
If ow (, ow or Hsh), the Ij da Yayashiro bell is output, and the laser drive circuit 47α (or 47b) irradiates the disc 28 with a low-output original beam of constant intensity to read the recorded information. I-V conversion processing circuit 37α (
Alternatively, the reproduction signal processing circuit 4
After FM demodulation at 0, the reproduced image is displayed on the TV receiver 41.

FIG. 1 shows the A-body configuration of the tracking control circuit 59, including a tracking error signal generation circuit 1α, a tracking error signal generation circuit 1b1, and a phase compensation circuit 2α.
, the phase compensation circuit 2 includes a switch 5a, a switch sb, an adder 4α, an adder 4A, a drive circuit 5α, and a drive circuit 5b1.
A tracking control circuit consisting of an actuator 6a and an actuator 6b, a waveform difference and shape circuit 7α, a waveform shaping circuit 7b, a control microcombination circuit 8, a memory 13, a converter 14α, and a D/A converter. 14b, switch 15α, switches 15, 6, switch 50α, and switch 50b.

The error signal generating circuit 1α (or 11S) generates a light spot from the tracking control signal (α's (bt (or (α勺, (jS')))' of the IV conversion circuit 57a (or 37b) in the 2gS diagram. A so-called S-shaped tracking error signal corresponding to the deviation of the information track [
C) (or (C)?I/ is generated, and the positional deviation between the optical spot and the information track is detected here. This signal is sent to the phase compensation circuit 2α (or 2b), the adder 4α (or 4b), and the drive Applied to actuator 6α (or 6b) via circuit 5 (L (or 5b),
Well-known tracking control is performed so that the optical spot always reproduces the same 1'# signal track.

Next, the operation of the eccentricity correction signal generation circuit will be explained. Figure 4 shows switch 3α (or 5b) set to 0/F.
When the tracking control is turned off with
, if you cross the information track as shown in Figure 4, you will see Figure 5 (2
) is a sinusoidal tracking error signal (-1) obtained as the output of the error signal generation circuit 1α (or IA). One cycle of this sinusoidal waveform corresponds to one track pitch, and this By counting the waveforms of the waves, the eccentricity δ1 of the eccentric component shown in FIG. 5 (11) can be determined.

Therefore, first, the switch 15α is turned OFF using the signal th) from the micro combinator 8, so that the correction signal is not applied to the actuator 6α, and the system controller
The switch 3a is turned OFF by the signal μ from the switch 45 to disable the tracking control, and the waveform shown in FIG. Turn on 50α, 50
b is turned off, and only the waveform-shaped signal V1 is input to the micro combinator 8. Micro Combiator 8
For example, the counter function 9, the calculation function 10. Memory function 11, timer machine This detection signal is waveform-shaped by the waveform shaping circuit 33 (in the d micro combiator 8 where d 1 is input to the micro combiator 8, this signal is used)
A waveform shaping circuit 7 that is input to one rotation of the disk in synchronization with
The output pulse V1 of α is counted by the counter 4 and the geometric 9,
Calculate the eccentricity δ1 of the disk. Includes 4 converters 14cL
The required amplitude r1 of the correction signal to be output from the D/A converter 14.6 is determined by jiWL (A/V), the voltage-current conversion coefficient of the drive circuit 5α and the drive circuit 5b, and the sensitivity of the actuator 6a and actuator 6b. α(
μmA).

If the amount of eccentricity is δ1, Vt == at /<ymma> (V)
It becomes +1+. The memory 13 stores sine wave data as shown in FIG. 6, for example, and the D/A converter 14
The α and 9 converter 14A outputs a voltage as shown in FIG. 7, for example, in accordance with the data trap from the micro combinator 8. At this time, the displacement of the actuator 6α and the actuator 6b of the memory 13 is given by the following equation.

Af H= (1-4-gin(2)τ/*)) No. 2
7 +2 where N is the total number of data, D is the input data of the RX converter 14α and the RX converter 14b, V & is the output voltage of the D/A converter, X is the actuator 6α,
The displacement of the actuator 6h, δm, is the displacement of the actuator when the output force of the D/A converter is x4.

In this way, the output current of the waveform shaping circuit 7a is
The eccentricity t is calculated from the value counted using the microcomputer 80 counter 9, and this eccentricity δ1
The micro combinator 8 performs calculations based on the contents of the memory 13 so as to obtain a sine wave force with an amplitude V corresponding to
Output to 4b.

Next, the operation of phase matching between the eccentric component and the correction signal shown in FIG. 5(1) will be explained. FIG. 8 shows the relationship between the number N of pulses obtained by the α1 waveform shaping circuits 7α and 7b (IC).

As shown in the figure, when the phase difference θ between the eccentric component and the correction signal is zero, the number of pulses N is the smallest, and even if the phase of the correction signal lags behind or leads the eccentric component from this point. Even if the number N of pulses is large, the number N tends to be large (for example, a correction signal (3) having a phase difference θ with respect to the eccentric component shown in FIG. 9, a correction signal (4) with a phase difference θ) , phase difference θ, are sent to the waveform shaping circuit 35.
When the number N of pulses of the tracking error signal obtained at this time is compared, θ, #θ3. If θ is in the relationship as shown in Figure 8, the number of counts will be minimum when a correction signal with a phase difference of 01 is output. Therefore, this characteristic is used to detect the phase shift between the eccentric component and the correction signal. Then, the phase is adjusted so that the phase difference becomes zero.

FIG. 10 is a timing chart showing the output state of the correction signal during phase matching. The method of phase matching will be explained below with reference to FIG. In the figure, (1) is the output signal (!11) of the waveform shaping circuit 53 in FIG. 3, (2) is the eccentric component, (51 is the signal output from the D/A converter 14α, and (4) is the D/A This is the signal output from converter 14.6.

First, from the D/A converter 14α, time 1o, 1. period of,
A correction signal (α) whose phase difference with the eccentric component (2) is 01 is output, and the phase difference during the period t1 to t is θ,=
The calculation function 10 calculates the correction signal tC1 such that θ, -
The output is performed by changing the heave address from the memory 15 using .

On the other hand, time t is output from D/A converter 14.6. - the period of
If the phase difference is 02=θ, +ψ, correct it to 5 with the key sign 1b.
+ is controlled by changing the read address from the memory 13 using the four-way calculation function 10 described above.

In the period from t1 to t1, the first factor switch 5oα is turned on.

When the switch 50b is turned OFF, the output pulse from the waveform shaping circuit 7α is sent to the counter function 9 of the microcomputer 8.
This is counted as A. During the period from t1 to t, the switch 50α is turned on and the switch 5ob is turned off, and the output pulses of the waveform shaping circuit 7α are counted and set as B or C, respectively.

The position of the correction signal when the count numbers A, B, and C obtained in each period are compared with each other using the arithmetic function 10 of the micro combinator 8 during the period of time t, ~t, and the count number becomes the minimum. Phase difference 'lJI: X mer.

For example, if the signal has a phase difference θ, processing is performed by the arithmetic function 10 so that at time t4, a correction signal with a phase difference θ is output from the appropriate converter 14a or 14b. The first phase matching operation ends at time t.

This is because the possible range of the phase difference between the eccentric component and the correction I100 in the first phase adjustment is ±180 degrees.

For example, if the initial phase change if 9'+ is 120 degrees, the comparison result of the number of pulses at the above three phase differences is 1j.
Therefore, the range of the phase match θ between the eccentric component and the correction signal can be kept within ±60 degrees.

The second phase adjustment is based on the correction signal of the phase difference θ when the number of reference points is the minimum in the first time, and the amount of phase change is also smaller than 9% (<9%).
θ, Junoj'! -ψ, three types of correction (1!
The memory 13 uses the arithmetic function 10 so that the number r is output.
The same operation as the first time as shown in FIG. 10 is performed by changing the read address of the data from. The phase difference between the eccentric component and the correction signal can be made within ±60 with the first phase adjustment, so if the second phase change amount ψ is 40 degrees, the eccentric component and the correction signal can be corrected with the second phase adjustment. The phase shift of the signal can be within ±20 degrees.

Thereafter, the value of the phase change amount ψ is further decreased and the same operation is continued.

Here, during the period t, ~t, of the first operation, the phase difference θ2
When it is determined that the case is the best, since the signal for the phase difference is output from the converter 14.6 at time t, the signal for the phase difference θ is output from the input converter 14A. When the correction signal for the phase shift θ is determined to be the minimum, it is output from the ≠ converter 14a.

When a signal with a phase difference θ is selected, a correction signal corresponding to the phase difference θ may be output from one of the router converters.

When the micro combinator 8 has obtained the optimum correction signal, it outputs the TOK signal σ1 to the system control 45 and performs normal reproduction. In normal recording/playback conditions, the system controller 45 and microcomputer 8 turn on switches 3α, sb and switches 15α, 15b1fg, and turn on the D/A converter 14a.
The correction signal output from (or 14b) and the signal output from phase compensation circuit 2α (or 2b) are added by adder 4a (or 4b) to drive actuator 6α (or 6b).

Note that, for convenience of explanation, the case where two pickups are used has been described here, but the invention is not limited to this. Further, correction signals having different output phases are obtained by controlling the read address of the memory 13 using the calculation 41121 (l) of the micro combinator 8, but the present invention is not limited to this.

14. As explained above, in the present invention, the influence of this distortion can be removed even in devices where the information track is distorted due to delamination or deformation of the recording medium, so it is possible to perform search or interlaced scanning. It is possible to perform this reliably, remove the glue a stalk from adjacent tracks, and eliminate the influence of eccentricity of the information track before tracking control operates.
Therefore, retraction can be performed stably. Furthermore, according to the present invention, since two pickups are used alternately, there is no need for complicated adjustments (and it can be carried out at low cost). can.

[Brief explanation of drawings]

FIG. 1 is a 1072 diagram of a tracking control circuit showing an embodiment of the present invention, FIG. 2 is a block diagram showing the structure of an optical head, FIG. 3 is a block diagram showing the structure of a recording/reproducing device, and FIG. 4 is a block diagram showing the structure of an optical head. Figure 5 is a waveform diagram showing the relationship between eccentricity and tracking error signal, Figure m6 is a diagram showing an example of data stored in memory, Figure 7 is a diagram showing the input of the D/A converter. A diagram showing an example of the output relationship, Fig. 8 shows the phase difference θ between the eccentric component and the correction signal and the count number N of the tracking error signal.
FIG. 9 is a waveform diagram showing the phase relationship between the eccentric component and the correction signal, and FIG. 10 is a timing chart showing the timing of output of the correction signal. Explanation of symbols 1αt1b: g4 difference signal generation circuit 2α, 2b: phase compensation circuit 6α, 6b near actuator α, 7b: waveform shaping circuit 8: microcomputer 9: counter function 10: arithmetic function 11: memory function 12: timer Function 13: Memory 14α, 144: D/A converter 16: Laser 28
: Disk 53 : lBL shape shaping circuit No. 4
Figure 5 Figure 6 Figure 6 Country of Wa

Claims (1)

[Claims] 1. In an optical information recording and reproducing device that uses a plurality of light spots on a rotating disk as an information recording medium to record and reproduce information on the disk, any one of the plurality of stationary light spots an eccentricity detection means for detecting the eccentricity of the disk by counting the number of times the spot crosses a track on the disk when the disk is rotated once using two optical spots; first means for generating a sinusoidal signal, the amplitude of which is determined by the eccentricity and the period of which is determined by the rotational period of the disk, given a rotational period of the disk; and an output of the sinusoidal signal; A second signal generating means generates a plurality of correction signals that differ only in phase, and an arbitrary sine wave signal from the second signal generating means is selectively inputted to each of the plurality of optical spots, and each excitation means for a plurality of optical spots so that the spots are given sinusoidal vibrations at different phases; and the disk is orthogonal to the excitation direction of the plurality of optical spots to which sinusoidal vibrations are applied. Selectively switch and count the number of times the plurality of spots cross the track on the disk when the disk is rotated once in the direction of rotation, and then compare the numbers with each other as a result of the comparison. means for adjusting the phase of the sinusoidal plate-like vibration from the second signal generating means applied from the excitation means to the light spot so that the number of vibrations decreases sequentially to a minimum number, and the light spot rotates. Information having a plurality of pickups, characterized in that, in addition to applying tracking control to the spots, the phase-adjusted sinusoidal vibration is applied to a plurality of optical spots so as to correctly track on the disk. Recording and playback device.