JPS6325411B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a converting means for reproducing a signal from a recording locus (hereinafter referred to as a track) of a signal recorded on a record carrier, and a scanning position of the converting means. The converter has a scanning movement means for moving in a direction substantially perpendicular to the track direction, a control means for controlling the scanning movement means so that the scanning position is on the track, and an opening/closing means for opening and closing a control loop of the control means. The present invention relates to a reproducing apparatus having a function of instantaneously interlacing the scanning position of a means to scan neighboring tracks.

2. Description of the Related Art As a reproducing device of this type, there is an optical reproducing device. This device converges a light beam generated from a light source onto a disk-shaped record carrier, and forms a concentric or spiral pattern on the record carrier. A light beam is controlled so that it is positioned on a track recorded on the record carrier, and a photodetector detects the light reflected from the light beam from the record carrier or the transmitted light transmitted through the record carrier, and reads the signal. It is. Generally, a He--Ne laser or a semiconductor laser is used as a light source, and audio signals or video and audio signals are recorded on the record carrier with unevenness or shading. For high-density recording with a track width of approximately 1 μm and a track pitch of approximately 2 μm, the light beam is focused to approximately 1 μm. Therefore, the converging lens for narrowing down the light beam must have a large numerical aperture and a short depth of focus. Focus control is performed in order to constantly irradiate this focused light beam onto the record carrier, but since focus control is not directly related to the present invention, detailed explanation will be omitted.

One of the important functions of the above-mentioned optical reproducing apparatus is to reproduce signals recorded on a record carrier, especially image signals, at an arbitrary speed.

In order to perform this special playback, it is necessary for the light beam on the record carrier to instantly skip track scanning from the track it is scanning to neighboring tracks.In conventional devices, the light beam on the record carrier is always This was done by opening the tracking control that controlled scanning on the track, applying positive rectangular pulses and negative rectangular pulses to the tracking element, and then closing the tracking control again (Special Publication No. 1973- Publication No. 50098).

Problems to be Solved by the Invention In the conventional method described above, it is extremely difficult to perform interlaced scanning on two or more tracks, and when there is eccentricity or uneven track pitch, it is difficult to perform interlaced scanning on one track. It also has the drawback of low probability and instability.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide an apparatus that can reliably and stably interlace scan not only one track but also many tracks.

Means for Solving the Problems The present invention provides a converting means for reproducing a signal recorded on a record carrier, and a reproduction position on the record carrier being reproduced by the converting means according to a track direction on the record carrier. scanning movement means for moving in a substantially perpendicular direction; scanning movement means for moving a playback position in a direction substantially perpendicular to the track direction on the record carrier; and positional deviation detection means for detecting a positional deviation between the playback position and the track. a first control means for controlling the scanning movement means so that the reproduction position is always on the track by driving the scanning movement means in response to a signal from the positional deviation detection means; A transport means for relatively moving in a substantially vertical direction; and a second drive means for driving the transport means according to a signal from the positional deviation detection means to control the relative positions of the scanning movement means and the record carrier to have a predetermined relationship. 2, a track crossing detection means for detecting when the playback position crosses a track, and a signal that is substantially applied to the scanning movement means to detect the playback position when searching for a target track that is several tracks away. means for generating a signal for moving toward the target track; means for inactivating the first and second control means while the playback position is being moved toward the target track; and track crossing detection means. a target track detecting means for detecting that the playback position has arrived on the target track by counting signals from the target track; and a signal substantially applied to the scanning movement means in response to the signal of the target track detecting means. This device includes means for generating a signal to stop the movement of the playback position.

Effects According to the present invention, with the above-described configuration, the conversion means performs track interlacing scanning by counting the times when the playback position on the record carrier being played back crosses the track, so that the playback position reaches the desired track. This enables reliable and stable multi-track interlacing scanning to be performed.

Example The present invention will be described in detail below with reference to the drawings.

Note that the same numbers are used to describe the same parts in the drawings.

FIG. 1 shows an embodiment of the apparatus of the present invention. light source 1
The light beam 2 generated from the recording medium 2 passes through an intermediate lens 3 and a semi-transparent mirror 4, is redirected by a total reflection mirror 5, and is focused onto a record carrier 7 by a converging lens 6. Light beam 2 reflected by record carrier 7
The reflected light 8 passes through the converging lens 6 again, is redirected by the total reflection mirror 5 and the semi-transparent mirror 4, and is
The light is received by the split photodetector 9. The respective outputs of the photodetector 9 are transmitted through amplifiers 10a and 10b.
is amplified by the envelope detection circuit 11.
a and 11b, and a differential amplifier 12 obtains a difference signal between envelope detection circuits 11a and 11b. Switches 13 and 14 are for opening and closing tracking control, and are linked and opened and closed at the same time. The compensation circuit 15 is for compensating the phase of the tracking control system, and the differential amplifier 12
The output of switch 13 compensation circuit 15, switch 1
4 and a drive circuit 16 to drive a tracking control element 17, that is, a scanning movement means. The total reflection mirror 5 is attached to a tracking element 17, and scans the light beam 2 focused on the record carrier 7 by the tracking element 17 in a direction perpendicular to the tracking direction. The record carrier 7 is rotated by an electric motor 18, and the record carrier 7 and the electric motor 18 are arranged to be movable by a transport motor 19 in a direction perpendicular to the track direction on the record carrier 7. A signal from the compensation circuit 15 is applied to the transfer motor 19 via a filter circuit 20 and a drive circuit 21, and when the switch 13 is short-circuited, the transfer motor 19 is applied to the tracking element 1.
It is driven so that the movement of 7 becomes zero on average.

The conversion means in the optical reproduction device includes a light source 1;
It is composed of an intermediate lens 3, a semitransparent mirror 4, a total reflection mirror 5, a converging lens 6, and a photodetector 9, and it irradiates a light beam 2 generated from a light source 1 onto a record carrier 7, The reflected light 8 from the photodetector 9
This is the part that receives light and reproduces the signal recorded on the record carrier 7, and is the magnetic head in a magnetic recording/reproducing apparatus.

Furthermore, the reproduction position on the record carrier that is being reproduced by the converting means, in the case of an optical reproduction device, means the position of the light beam 2 focused on the record carrier, and also means the position of the magnetic head. There is.

Positional deviation detection for detecting positional deviation in the optical time tracking device This is a positional deviation detection means for detecting the positional deviation between the light beam and the track on the record carrier 7 when flying, and in FIG. Amplifiers 10a, 10b, envelope detection circuit 11
a, 11b and a differential amplifier 9.

The relationship between the tracking element 17 and the transfer motor 19 is such that tracking is performed by scanning the light beam 2 with the tracking element 17 against sudden displacements such as eccentricity of the track on the record carrier 7, and the driving voltage of the tracking element 17 is The transfer motor 19 is driven so that the value becomes zero on average. Switch 22 is opened and closed by inverting circuit 23, but its opening and closing operation is completely opposite to that of switches 13 and 14.
A is a synchronizing pulse input for interlacing scanning (hereinafter referred to as yapping) of a track, and b is an output obtained by adding the outputs of the amplifiers 10a and 10b by the sum circuit 24. The jumping stop pulse generating circuit 25 confirms that the light beam 2 crosses the track on the record carrier 7 and is on the designated track based on the output of the summation circuit 24, and outputs a pulse to stop jumping. The jumping command circuit 26 outputs a jumping command based on the jumping synchronization pulse, and outputs a jumping stop command based on the output of the jumping stop pulse generating circuit 25. A jumping voltage generation circuit 27 generates a jumping voltage from the output of the jumping command circuit 26, and outputs a jumping voltage to the switch 22 and the drive circuit 16.
The tracking element 17 is driven through the. Furthermore, the process of jumping will be explained in detail.

When jumping is not being performed, switches 13 and 14 are closed, and switch 22 is closed.
is open. Therefore, tracking control is in effect. When a jumping synchronization pulse is input to A in this state, the jumping command circuit 26 outputs a jumping command, switches 13 and 14 are opened, the tracking control is in the open state, and at the same time as the switch 22 is closed, a jumping voltage is generated. The circuit 27 generates a jumping voltage and drives the tracking element 17 via the switch 22 and the drive circuit 16. The light beam 2 is scanned by a total reflection mirror 5 attached to a tracking element 17 in a direction perpendicular to the track direction on the record carrier 7, and traverses the track. The jumping stop pulse generation circuit 25 generates a jumping stop pulse after confirming that the light beam 2 crosses the track and is on the predetermined track, and in response to this pulse, the jumping command circuit 26 outputs a jumping stop command. Close switch 13 and switch 14, apply tracking control, and switch 22
to open. Therefore, while jumping is being performed, the switch 13 is open and the transfer conductor 19 does not move. The jumping stop pulse generation circuit 25 will be explained with reference to FIG. The output A of the sum circuit 24 is input to an envelope detection circuit 31, and further input to a counting circuit 34 via a comparison circuit 32 and a waveform shaping circuit 33. The output of the setting circuit 35 for setting the number of jumping lines and the output of the counting circuit 34 are input to a coincidence circuit 36, and when the outputs of the setting circuit 35 and the counting circuit 34 become equal, the coincidence circuit 36 generates a jumping stop pulse. At the same time, the counting circuit 34 is reset. The relationship between the signals from the sum circuit 24 to the waveform shaping circuit 33 will be explained with reference to FIG. a is the output of the summation circuit 24 when the light beam 2 crosses the track, b is the output of the envelope detection circuit 31, c is the output of the comparison circuit 32, and d is the output of the waveform shaping circuit 33. It is desirable that the comparator circuit 32 has hysteresis to prevent malfunction. Further, the waveform shaping circuit 33 is for preventing malfunction, and the output of the comparator circuit 32 is transferred to the counting circuit 3.
4 can be entered directly. Also, the sum circuit 24
Instead of performing envelope detection on the output of the envelope detection circuit 31, the envelope detection circuit 11
Either one of the outputs of outputs a and 11b or the sum signal can be used.

The jumping voltage generating circuit 27 will be explained with reference to FIG. When a jumping command is input from the jumping command circuit 26 to (c), the pulse generating circuit 41 generates a pulse, and at the same time, the triangular wave generating circuit 42 generates a voltage of y=at. t is the time from when the jumping command is inputted to C from the jumping command circuit, and a is the slope of the voltage y generated from the triangular wave generating circuit 42. The voltage y becomes zero when a jumping stop command is input from the jumping command circuit 26 to c. The outputs of the pulse generating circuit 41 and the triangular wave generating circuit 42 are combined by a combining circuit 43, and the output thereof is input to the switch 22 and drives the tracking element 17 via the driving circuit 16.

The jumping voltage for making the jumping stable will be explained. In the case of jumping, it is necessary that the tracking control system can adjust to the relative speed between the moving speed of the light beam 2 on the record carrier 7 and the moving speed of the track due to eccentricity or track pitch unevenness. There is a limit to the relative speed that the tracking control system can pull in, and if the relative speed exceeds the limit, the truck will not be pulled into a predetermined detected track but will be pulled into another track that has gone too far. To ensure stable retraction, it is desirable to apply a reverse pulse for braking to reduce the relative movement speed between the light beam 2 and the track to the retraction speed of the tracking control system or less at the same time as the jumping stop command to prevent overshoot. If the light beam 2 on the record carrier 7 is not moving at a constant speed, it is necessary to change the shape of the reverse pulse to match the speed of the light beam 2. Therefore, a means for detecting the speed of the light beam 2, etc. is required, and the apparatus becomes very complicated. Therefore, if the light beam 2 moves at a constant speed and a reverse pulse of a constant shape is always added, an extremely simple device can be obtained.

The tracking element 17 may be a galvanometer mirror or a piezoelectric element, but the frequency characteristics of these elements can generally be approximated by a quadratic form, and the transfer function G
(s) can be expressed as G(s)=Aω ² _o /(S ² +2ω _o S+ω ² _o ). S is the Laplace operator, A is the sensitivity including the optical system, is the damping coefficient, and ω _o is the natural oscillation angular frequency. In order to move the light beam 2 at a constant speed using such a tracking element 17, the voltage applied to the tracking element 17 is V〓(s)=(k/Aω ² _o )×(1+2ω _o /S+ω ² _o
/
S ₂ ), and by inverse Laplace transform, L ^-1 [V(s)] = (k/Aω ² _o ) δ(t) + (2k/
Aω _o )U(t)+k/At. k is the velocity of the light beam 2 on the record carrier 7, δ(t) is the delta function and U(t) is the single step function.

From the above, if the voltage input to the tracking element 17 is a composite voltage of a pulse voltage, a step voltage, and a ramp voltage, the light beam 2 can be moved at substantially constant speed. ω _o is generally 2π×
Since about 30 or more are used, the pulsed voltage becomes extremely small, and even if omitted, the light beam 2 can be moved at almost constant speed.

The above will be explained with reference to FIG. sum circuit 5
1 outputs a composite voltage of the outputs of the pulse generation circuit 52, step voltage generation circuit 53, ramp voltage generation circuit 54, and inverse pulse generation circuit 55, and
and input to switch 57. The jumping command circuit 26 is operated by the jumping synchronization pulse input A and the jumping stop pulse input O, and the pulse generation circuit 52, step voltage generation circuit 53, and ramp voltage generation circuit 54 start operating at the same time as the jumping synchronization pulse, and vice versa. The pulse generating circuit 55 starts operating simultaneously with the jumping stop pulse. The input terminal is an input terminal for determining the direction of jumping, and it operates the switch 57 or switch 58, and both switches 57, 5
The tracking element 17 is driven by the output key of No. 8 via the drive circuit 16, and at the same time, the switches 13 and 14 are operated by the output key of the jumping command circuit 26 to perform jumping.

The above operation will be explained in more detail with reference to FIG. FIG. 6 shows the case where the setting circuit 35 is set to jump two lines, where a is the output of the sum circuit 24, b is the jumping synchronizing pulse, and c
is the output of the waveform shaping circuit 33 which generates a pulse at the same time as the light beam 2 on the record carrier 7 crosses the track, d is the output of the coincidence circuit 36 which generates a jumping stop pulse, e is the jumping command circuit 2
6, f is the waveform of the jumping voltage output.

The temporal relationship between waveform a and waveform c is such that a signal (waveform c) traverses the track between the moment when the light beam 2 on the record carrier 7 enters the track and the moment when it reaches the center of the track, Although it is desirable to stop the jumping, it is also possible to cause the jumping to stop between the moment the vehicle reaches the center of the track and the moment it exits the track.

Further, the temporal relationship between the waveforms e and f can be such that the tracking control is closed after the reverse pulse of the jumping voltage output key (waveform f) is output.

Switch 13 for opening and closing tracking control
and 14 may not be opened and closed at the same time, but the switch 13 may be opened and closed later than the switch 14. It is also possible to use only the switch 14, but if the loop gain of the tracking control system is set large, the circuit will become saturated when the tracking control is left open, creating a non-linear portion, and the pull-in may become unstable. Furthermore, by holding the tracking drive voltage just before jumping and adding it to the jumping voltage, even more stable jumping can be achieved. As the jumping synchronization pulse input a, a vertical synchronization signal of an image signal or a frequency-divided version of the vertical synchronization signal can be used.

The present invention has been explained above using an optical reproducing device as an example, but it can also be applied to a magnetic reproducing device that uses a magnetic material as a record carrier, a capacitive reproducing device that uses a record carrier in which a signal is recorded by changing the capacitance due to unevenness, etc. Needless to say, it can also be used.

Effects of the Invention As explained above, according to the present invention, still images, slow motion images, quick motion images, and back motion images can be reproduced at a time different from the time recorded on a record carrier. Special reproduction images can be stably obtained. The present invention can also be applied to a search device that records still images concentrically and whose purpose is to instantly search and reproduce a desired still image.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
2 is a specific configuration diagram of the jumping stop pulse generation circuit 25 shown in FIG. 1, FIG. 3 is an explanatory waveform diagram when the light beam 2 crosses the track, and FIG.
FIG. 5 is a block diagram showing one embodiment of the jumping voltage generating circuit 27, and FIG. 6 is a waveform diagram illustrating each part of FIG. 5. DESCRIPTION OF SYMBOLS 1... Light source, 5... Total reflection mirror, 7... Record carrier, 9... 2-split photodetector, 11a, 11b...
...Envelope detection circuit, 12...Differential amplifier,
15... Compensation circuit, 16, 21... Drive circuit, 1
7... Tracking element, 18... Electric motor, 19
...Transfer motor, 20...Filter, 23...
Inversion circuit, 24... Sum circuit, 25... Jumping stop pulse generation circuit, 26... Jumping command circuit, 27... Jumping voltage generation circuit.

Claims (1)

[Claims] 1. A converting means for reproducing a signal recorded on a record carrier, and a reproduction position on the record carrier that the converting means is reproducing, which is substantially perpendicular to the track direction on the record carrier. scanning movement means for moving in a direction;
a positional deviation detecting means for detecting a positional deviation between the reproduction position and the track; and a first apparatus for controlling the scanning movement means so that the reproduction position is always on the track by driving the scanning movement means in accordance with a signal from the positional deviation detection means. a control means, a transport means for relatively moving the scanning movement means and the record carrier in a direction substantially perpendicular to a track direction on the record carrier, and driving the transport means in response to a signal from the positional deviation detection means. , second control means for controlling the relative positions of the scanning movement means and the record carrier to have a predetermined relationship; track crossing detection means for detecting that the reproduction position crosses a track; and the scanning movement means. means for generating a signal that is substantially applied to a target track and moves the playback position toward the target track when searching for a target track several tracks apart; and means for inactivating the first and second control means while the track is being moved toward the target track, and counting signals from the track crossing detection means so that the playback position is located on the target track. and means for generating a signal that is substantially applied to the scanning movement means and that stops the movement of the playback position in response to the signal from the target track detection means. A playback device characterized by: 2. The playback device according to claim 1, wherein the track crossing detection means is configured to detect when the playback position crosses a track based on the signal from the conversion means. 3. The playback device according to claim 1, wherein the track crossing detection means is configured to generate a signal indicating that the track has been crossed before the playback position passes through the center of the track. 4. The playback device according to claim 1, wherein the playback device is configured to operate the first control means again upon detecting that the playback position has come to a target track. 5 After the playback position reaches the target track and a signal to stop the movement of the playback position is generated, the first
2. The reproducing apparatus according to claim 1, wherein the reproducing apparatus is configured to operate the control means again.