JPS60121577A - Retrieving device of information track - Google Patents

Abstract

PURPOSE:To execute the stable retrieving by having the waveform processing so that an accurate track traversing signal can be detected even if the scanning position moves and a reproduced signal which is obtained from a changing means changes to DC when a transfer stand is moved by setting the tracking control means as nonoperation. CONSTITUTION:When the speed of a transfer srand 71 is slow, that is, the output of a comparator 73 is in the LOW condition, a tracking element 56 does not oscillate, and therefore, for the output of a differential amplifier 60, noises of the high-frequency components are removed by a low-pass filter 80 of a waveform processing circuit 62, and an output (b) is inputted to a counting circuit 74 by selecting it through a switch 66. When the speed of the transfer stand 71 is fast, the output of the comparator 73 becomes to the HIGH condition, low-frequency component waves which are generated by the oscillation of the tracking element 56 are removed by a band pass filter 81, and at the same time, the high frequency component noises are removed and outputted. An output (c) is selected through the switch 66, and inputted to the counting circuit 74.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a recording/reproducing device for recording or reproducing information using a signal conversion means on a disc-shaped record carrier having a track on which information is recorded or a track for recording information. The present invention relates to an information track retrieval device.

Conventional Structure and Problems There is an optical recording/reproducing apparatus as one of the suitable recording/reproducing apparatuses to which the present invention is applied.

A conventional optical recording/reproducing device will be explained with reference to FIGS. 1 and 2.

FIG. 1 is an explanatory diagram of an optical recording/reproducing device.

The original beam 2 generated by a light source 1 such as a semiconductor laser is passed through a coupling lens 3. The light passes through a beam splitter 4, is reflected by a reflecting mirror 6, and is focused onto a disc-shaped record carrier 7 by a converging lens 6.

The record carrier 7 is attached to the rotating shaft of a motor 8 and rotates at a predetermined number of rotations. The record carrier 7 has concentric or spiral grooves (hereinafter referred to as tracks) on a base material, and is composed of a recording material layer and a protective layer provided thereon. Address signals are provided sequentially from the inner circumference to the outer circumference. The reflected light of the original beam 2 reflected from the record carrier 7 passes through the converging lens 6 again, is reflected by a reflecting mirror 5 and a beam splitter 4, and is irradiated onto a photodetector 9 having a two-split structure. The zero convergence lens 6 is attached to the tracking element 10,
The tracking element 10 is configured such that the converging lens 6 can be moved in the radial direction of the record carrier 7, ie in a direction substantially perpendicular to the direction of the tracks on the record carrier 7. light source 1
, the coupling lens 3 , the beam splitter 41 , the reflecting mirror 6 , the photodetector 9 , the tracking element 10 and the speed detector 11 are attached to the transfer table 12 .

It is configured to move integrally with the record carrier 7 in the radial direction by means of a linear motor 13 .

The speed detector 11 has a V-configuration consisting of a moving part made of a rod-shaped magnet fixed to the moving table 12 and a fixed part made of a coil.

Outputs a signal according to the

Tracking control for controlling the source beam 2 focused on the record carrier 7 so that it is always positioned on the track will be described. Each signal of the photodetector 9 is transmitted to a differential amplifier 14.
The differential amplifier 14 outputs a difference signal between the respective signals of the photodetector 9. The direction of the dividing line of the photodetector 90 is the track direction of the track pattern included in the reflected light on the photodetector 9, and the signal from the differential amplifier 14 represents the positional relationship between the original beam 2 on the record carrier 7 and the track. The signal, ie, the tracking control signal, is well known and will not be described in detail. The signal from the differential amplifier 14 is transmitted to the tracking element 10 via a switch 15, a phase compensation circuit 16 for compensating the phase of the tracking control system, and a drive circuit 17 for driving the tracking element 10.

The tracking element 10 is moved by the converging lens 6'f according to the signal from the differential amplifier 14, and is controlled so that the original beam 2 on the record carrier 7 is positioned on the track.0 Movement of the tracking element 10 The possible range is about 500 μm, and if the transfer table 12 moves too far, the tracking control will be lost. In order to prevent this, the linear motor 13 is driven so that the tracking element 10 moves around its natural state, that is, the signal from the drive circuit 1 reaches zero level on average, and the movement of the transfer table 12 is performed. is under control. To explain this transfer control, the differential amplifier 14
The 0 signal is transmitted to the linear motor 13 through a switch 15, a phase compensation circuit 18 for compensating the phase of the transfer control system, and a drive control circuit 19 for driving and controlling the linear motor 13. 13 is tracking element 1
The transfer table 12 is moved so that o moves around its natural state. The switch 15 is for disabling tracking control and transport control.

The signal from the speed detector 11 is inputted manually to the drive control circuit 19, and by feeding back the speed signal, linear mode and evening drive control are made more stable.

Recording and reproduction of signals will be explained. When recording a signal on a track on the record carrier 7, the intensity of the original beam 2 generated from the light source 1 is modulated in accordance with the recording signal while the tracking control and the transport control are operated. The recording material D[, which is irradiated with the strong original beam 2, changes its state or shape, and a signal is recorded on the track on the record carrier 7. When reproducing a signal recorded on a track on the record carrier 7, the original beam 2 generated from the light source 1 is made to have a weak constant light intensity while the tracking control and transport control are operated, and the reflection from the track is The light is received by the photodetector 9, and a composite signal of the respective signals of the photodetector 9 is obtained.

Note that in the optical recording/reproducing device, focusing is controlled so that the beam diameter of the original beam 2 irradiated onto the record carrier 7 is always constant, but this is not directly related to the present invention and will be described in detail. Avoid.

The basic configuration of the optical recording/reproducing device has been described above, but one important function of this device is to search for a desired track at high speed and stably, and this search will be explained below.

The search system is composed of an information processing control device 20 including a microcomputer. Address A of the desired track in the address input device 21. When input, the information processing control device 20 reads the address of the track where the light beam 2 is currently located, and calculates (A, -80).
l person + 'o 1m' (IA, -A. l is (A1 - A
represents the absolute value of o).

Further, N is a positive integer. ] Then information processing control device 2
0 is IA, -Aol value and direction signal to drive control circuit 1
9 includes a counting circuit [I] included in the feed drive control circuit 19.
A, -A. Preset the value of 1 and at the same time switch 15
is opened, and tracking control and transfer control are disabled. The drive control circuit 19 drives the linear motor 13 to move the transfer platform 12 in the direction where a desired track exists.

The signal from the differential amplifier 14 is input to a track crossing detection circuit 22, and the signal from the track crossing detection circuit 22 is input to a drive control circuit 19.

When the transfer table 12 moves in the radial direction of the record carrier 7.

A signal indicating that the original beam 2 on the record carrier 7 crosses a track is outputted from the differential amplifier 14 , and the track crossing detection circuit 22 shapes the signal from the differential amplifier 14 and sends this signal to the drive control circuit 19 . to communicate. Drive control circuit 19
A counting circuit included in the circuit counts the signals of the track crossing detection circuit 22 and determines whether the original beam 2 on the record carrier 7 is IA, - person.

The drive control circuit 19 detects that it is on the track of the first tree, and sends a coincidence signal to the information processing control device 20. The information processing control device 20 has m for stopping the linear motor 13.
transmitting the signal to the drive control circuit 19 and short-circuiting the switch 16 to operate tracking control and transfer control;
0 to read the address 2 of the track where the original beam 2 is located on the record carrier 7 (hereinafter this search will be referred to as a coarse search).
If Ao=A2, the search ends, but 1mu2-muo1≧
If N, the above-mentioned rough search is performed again. If 1m2-AoI<N, the information processing control device 20 opens the switch 16, sends a signal to the drive circuit 17, drives the tracking element 1o, and switches 16f again:
Single track interlaced scanning (
Hereinafter, this scanning will be referred to as jumping. ), and after repeating this jumping IA2-Aol times, read the address M3 of the track where the original beam 2 is located (
Hereinafter, this search will be referred to as a dense search. ). If Ao-A, the search ends, but if Ao-A, (Mu0-A means that A. and A are not equal), the above-mentioned coarse search and fine search are repeated. A simple structure of the tracking element 10 for searching a desired track will be explained with reference to FIG. Note that the same numbers are used for the same parts as in FIG. A converging lens 6 is attached to the tip of the cylinder 31, and coils 32 and 33 are also attached to the cylinder 31. The chassis 34 and the cylinder 31 are connected by rubbers 35 and 36. Yokes 37 and 42 forming a magnetic circuit are attached to the chassis 34. York 37
A magnet 4o is inserted between the yokes 38 and 38, a magnet 41 is inserted between the yokes 38 and 39, a magnet 45 is inserted between the yokes 42 and 43, and a magnet 46 is inserted between the yokes 43 and 44. It forms a magnetic circuit. When current flows through the coils 32 and 33, the cylinder 31 is configured to move due to the electromagnetic force received by the coils 32 and 33. The original beam 2 is configured to pass through the cylinder 31, and the cylinder 3
1 moves, the converging lens 6 moves, and the original beam 2 converged on the record carrier 7 moves in a direction substantially perpendicular to the track direction.
When the tracking element 10 is moved at high speed, the tracking element 10 vibrates greatly due to inertia, and the differential amplifier 14 does not output a normal signal across the track. Because the numbers were not transmitted, rough searches were performed many times, severely impairing the stability of the device.

In order to eliminate the above-mentioned drawbacks, in the conventional device, the linear motor must be moved at low speed during rough search, and the time to search for a desired track (hereinafter referred to as search time) becomes extremely long. OBJECT OF THE INVENTION The object of the present invention is to eliminate the above-mentioned drawbacks, and to move the linear motor 13 at high speed during a rough search so that even if the tracking element 10 vibrates, it is possible to search for a desired track at high speed and stably. The aim is to provide the equipment.

DESCRIPTION OF THE INVENTION The present invention relates to a record carrier having tracks for recorded signals or tracks for recording signals.

a converting means for reproducing a signal from or recording a signal on a track on a record carrier; and a first converting means for moving a scanning position of the converting means in a direction substantially perpendicular to the track direction on the record carrier. a second moving means for moving the scanning position of the converting means including the first moving means in a direction substantially perpendicular to the track direction on the record carrier; It has a tracking control means for driving and controlling the first moving means so that it is always positioned on the track on the carrier, and a waveform processing means for processing the waveform of the reproduced signal obtained from the conversion means. When the second moving means is moved with the control means inoperative, the first moving means is moved by the movement of the second moving means, and the reproduced signal obtained from the converting means is accurate even if DC changes. The waveform processing is performed so that the track-crossing V signal can be detected, and a stable search can be performed.

Description of examples Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 3 shows one embodiment of the present invention. In explaining FIG. 3, parts that overlap with those in FIG. 1 will be briefly explained.

61 is a light source, 52 is a coupling lens, 63 is a beam splitter, 164 is a reflecting mirror, 66 is a converging lens, 66
if:) A racking element, 57 is a record carrier, 6B is a motor, and 69 is a photodetector with a two-part structure. Photodetector 69
The respective signals are input to a combining circuit 61 for obtaining a combined signal of the respective signals of the differential amplifier 60 and the photodetector 69. The signal of the differential amplifier 60 is sent to the waveform processing circuit 6
2 and switch 83, and the output of switch 63 is input to phase compensation circuit 64 and e5. The signal from the phase compensation circuit 64 is sent to the drive circuit 67.

Signals from the drive circuit 67 are input to the tracking elements 66, respectively. The signal of the phase compensation circuit 66 is sent to the synthesis circuit 6
8, the signal of the combining circuit 68 is input to a drive circuit 70 for driving the linear motor 69, and the signal of the driving circuit 70 is input to the linear motor 69, respectively. A signal from a speed detector 72 that outputs a signal corresponding to the moving speed of the transfer table 71 is input to a synthesis circuit 68 and a comparator 73. A specific example of the comparator 73 is shown in FIG. The output signal f of the speed detector T2 is
The voltage is input to inverting amplifiers 85 and 86 and compared with the respective voltages, and the respective outputs are added and input to the switch 66 as the output q of the comparator 73.

Here, the absolute value of the output signal I of the speed detection booklet 2 increases as the speed of the transfer table 71 increases, and the inverting amplifier 85.8
6, the output q of the comparator 73 becomes LIOW state. Further, as the speed of the transfer table 71 becomes slower, the absolute value becomes smaller and the output q of the comparator 73 becomes HiGH. It is assumed that the polarity of the housing changes depending on the direction in which the transfer table 71 moves. The signal from the waveform processing circuit 62 is sent to the switch 66.
The 0 signals are input to the divider circuits 74, respectively. The counting output of the counting circuit 74 is transmitted to the signal generating circuit 75, and the signal of the signal generating circuit 76 is transmitted to the combining circuit 68 via the switch 76. The synthesis circuit 68 is a speed detector 72
, the phase compensation circuit 65, and the switch 76.

To briefly explain the search, enter the address of the desired track on the address input device 7. When input, the information processing control device 78 reads the address of the track where the original beam is located on the record carrier 67 from the signal of the combining circuit 61, and if 1muj'01≧N, the counting circuit 74 to 1 mu 1-
The value of Mol is preset, and a direction signal is sent to the signal generation circuit 76 (the direction signal is a signal indicating whether to move the transfer stage 71 from the outer circumference to the inner circumference of the record carrier 57 or from the inner circumference to the outer circumference). ).

Thereafter, the information processing control device 78 opens the switch 63, disables the tracking control and transfer control, and sends signal 4g to the switch 76. switch 7
6 is short-circuited, and the signal from the signal generation circuit 75 is transferred to the synthesis circuit 68.
to communicate. The signal generation circuit 76 outputs a signal corresponding to the count output of the counting circuit 74 and the direction signal of the information processing control device 78.
In response to the signal, the transfer table 71 is moved in the direction where the desired track is located. The counting circuit 74 counts the number of tracks crossed by the original beam on the record carrier 57.
Since the transfer table 71 causes a speed change (the output of the speed detector 72 at this time is shown in FIG. 4A), the tracking element 5
6 vibrates, and the output signal of the differential amplifier 60 causes a DC voltage change (undulation in the output signal) as shown in FIG. 4C. Two specific examples of the waveform processing circuit 62 for removing this DC voltage change are shown in FIGS. 6 and 7. - Example In FIG. 6, the output signal of the differential amplifier 6o is input to a low pass filter 80 and a band pass filter 81. When the speed of the transfer table 71 is slow, that is, when the output q of the comparator 73 is LOW, the tracking element 1° does not vibrate at the beginning of FIG.
High frequency component noise is removed from the 0Ω output signal by a low-pass filter 80, and the signal is output to b. The output signal is input to a switch 66, which selects the output signal of the waveform processing circuit 62 when the signal from the comparator 73 is in the LOW state, and selects the output signal from the counting circuit 7.
4 [Enter. When the speed of the transfer table 71 increases, the comparator 7
The output q of 3 becomes the HiGH state in FIG.
At the same time, high frequency component noise is removed and output to C.

The output C is input to the switch 66, and the switch 66 selects the output C of the waveform processing circuit 62 and inputs it to the counting circuit 74 when the signal from the comparator 73 is in the HiGH state. Therefore, the waveform input to the counting circuit 74 becomes 4l;, which is obtained by removing the ridge V from the waveform shown in FIG. 4c.

In the second example shown in FIG. 7, the output signal a' of the differential amplifier 6o is input to the DC clamp circuit 84. The output of the DC clamp circuit 84 is passed through two low-pass filters 82 with different station wave numbers.
．． At 83, the outputs of the low-pass filters 82 and 83 are respectively input to the switch 66.

A specific example of the DC clamp circuit 84 is shown in FIG.

The signal input to VDC is completely cut off by the capacitor C4, and is connected to the resistors R, , R8 and the diode D4. Transistor TR outputs only the positive side of the polarity of the input signal to β. Therefore, the signal output from differential amplifier 6° is shown in Figure 4).
・Even if the throat fluctuates, 4 of the comparator 73
M signal causes the switch 66 to output the output b of the waveform processing circuit 62.
When ', c' are switched and inputted to the counting circuit 74, the signal is a ridge V (DC change) of the low frequency component as shown in Fig. 4 (e).
is removed.

Therefore, the signal corresponding to the track traversed by the original beam on the record carrier 6 can be accurately input to the counting circuit 74. The counting circuit 74 counts the input signal and calculates lA+-Ao.
It is detected that the original beam is on the first 0 track, and a coincidence signal is sent to the information processing control device 78.

The information processing control device 78 sends a signal to the switch 76 and the speed change detection circuit 73 to open the switch 76 and stop the linear motor 69, and also sends a signal to the tracking element 56 as a change signal over time in the moving speed of the transfer table 71.
Information processing control device 78 that prevents information from being transmitted to
sends a signal to the switch 63, short-circuits the switch 63, operates the tracking control and the transport control, and reads the address A2 of the track on the record carrier 67 where the source beam is located. A2. If it is 2Ao, end the search.

If lA2-Aol≧N, the coarse search described above is performed, and if lA2-Aol<N, all the fine searches described above are performed to search for the desired track.

In the explanation of FIG. 7, two low-pass filters 82 and 83 with different cutoff wave numbers are used, but a single low-pass filter may be used.

Effects of the Invention By applying the present invention, even if the transfer stage is moved at high speed and the tracking element vibrates, the tracks traversed by the original beam on the record carrier can be accurately counted, even if they are superimposed on the output of the width transducer. Accurate, high-speed searches can be performed, and the performance and reliability of the device can be significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional optical recording/reproducing device, FIG. 2 is a cross-sectional view of a main part of a tracking element, and FIG. 3 is a block diagram illustrating an embodiment of an information track retrieval device of the present invention. , FIG. 4 is an operation waveform diagram of the same embodiment, FIG. 5 is an electric circuit diagram for comparing speed detection signals, and FIG. 6 is an electric circuit diagram for comparing speed detection signals. FIG. 7 is a block diagram showing essential parts of an embodiment of the present invention, and FIG. 8 is an electric circuit diagram showing an example of a DC clamp circuit. 50... light source, 65... converging lens,
66. Tracking element, 57... Disk, 59... Photodetector, 6o... Differential amplifier, 61. 68... Synthesizing circuit, 62・・・・・・
...Waveform processing circuit-63, 76...Switch,
64.65... Phase compensation circuit, 67°70...
...Drive circuit, 69...Linear motor, 72 device, 78...Information processing control device, 80, 82
. 83...Low pass filter, 81...
・Band pass filter, 84...DC clamp circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 Figure 4 Figure 6 Figure 7 Figure I Figure 8

Claims (1)

[Scope of Claims] (1) A record carrier having a track for a recorded signal or a track for recording a signal, a converting means for reproducing or recording a signal from a track on the record carrier, and the converting means. a first moving means for moving the scanning position of the converting means in a direction substantially perpendicular to the track direction on the record carrier; a second moving means that moves including the first moving means; and a control means that drives and controls the first moving means so that the scanning position of the converting means is always on a track on the record carrier. , speed detection means for detecting the speed of the second moving means; and when the second moving means is moved with the control means inoperative. and a waveform processing means for removing DC changes in the reproduced signal obtained from the conversion means, and configured to drive and control the second moving means while counting the output signal of the waveform processing means. An information track search device featuring 0? ] Information track retrieval device 0 according to claim 1, characterized in that the waveform processing means is composed of a DC clamp circuit and a low-pass filter; (3) the waveform processing means is composed of a low-pass filter; It is characterized by being configured with a band-pass filter, and configured to switch between the output of the low-pass filter and the output of the band-pass filter in accordance with the output state of speed detection means for detecting the speed of the second moving means. An information track retrieval device according to claim 1.