JPH057790B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention comprises tracking control means for controlling the scanning position of a converting means for reproducing a signal recorded on a record carrier to be located on a track. The present invention relates to a reproducing apparatus, and particularly to track interlacing scanning in which the scanning position of a converting means is instantaneously moved to a desired track when necessary.

BACKGROUND ART Conventionally, optical recording and reproducing devices, magnetic recording and reproducing devices,
Magneto-optical recording and reproducing devices, capacitive reproducing devices, and the like are known. In these devices, track interlacing scanning is performed when performing special reproduction or when searching for a desired track.

Problems to be Solved by the Invention The above-described device is characterized in that the scanning position of the converting means on the record carrier is moved in a direction across the track in response to sudden displacements such as eccentricity of the track on the record carrier. Since it is composed of two moving means: a moving means and a second moving means that moves so that the scanning position traverses the track over a wider range than the first moving means, when scanning between tracks, both moving means are used. It was difficult to perform stable track interlacing scanning due to the movement of the track.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the conventional apparatus and to provide an apparatus capable of performing stable track interlacing scanning with a simple configuration.

Means for Solving the Problems The present invention provides a converting means for reproducing a signal recorded on a record carrier, and a first transducer in which the scanning position of the converting means on the record carrier moves in a transverse direction. a moving means, a second moving means for moving the scanning position in a direction across the track over a wider range than the first moving means, and a positional deviation detection means for detecting a positional deviation between the track on the record carrier and the scanning position. ,
a control means for driving the first and second moving means in response to a signal from the positional deviation detection means so as to position the scanning position on the track; and an opening/closing means for disabling the control means; scanning signal generating means for generating a signal for intertrack scanning to move the scanning position toward a desired track; and an opening/closing means that disables the control means and applies the signal of the scanning signal generating means to the first moving means. The apparatus is constructed of a track interlacing scanning means for performing track interlacing scanning.

Effects According to the present invention, when performing track skipping scanning, the opening/closing means disables the control means and applies the signal from the scanning signal generating means to the first moving means to instantly change the scanning position of the converting means to the desired position. Since the second moving means is not driven by the scanning signal, extremely stable track interlacing scanning can be performed.

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

FIG. 1 shows one embodiment of the invention. A light beam 2 generated from a light source 1 passes through an intermediate lens 3 and a semi-transparent mirror 4.
, the direction is changed by the total reflection mirror 5,
The light is focused onto a disc-shaped record carrier 7 by a converging lens 6. The reflected light 8 of the light beam 2 reflected by the record carrier 7 passes through the converging lens 6 again,
The direction of the light is changed by a total reflection mirror 5 and a semi-transparent mirror 4, and the light is irradiated onto a photodetector 9. Photodetector 9
has a two-division structure so as to have two light-receiving areas, and each output is sent to amplifiers 10a and 10.
b, and the envelope detection circuit 11
a, 11b, the envelope detection circuit 11 is detected by the differential amplifier 12.
A difference signal between a and 11b is obtained.

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 output of the differential amplifier 12 drives the tracking element 17 via the compensation circuit 15 and the drive circuit 16. 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 configured to be movable by a transport motor 19 in a direction perpendicular to the track direction on the record carrier 7. Transfer motor 19
The output of the compensation circuit 15 is driven by a drive circuit 21 via a filter circuit 20. The transport motor 19 is driven in such a way that the light beam 2 focused on the record carrier 7 is located evenly on the track.
The relationship between the tracking element 17 and the transport motor 19 is such that the tracking element 17 scans the light beam 2 to track sudden displacements such as eccentricity of the track on the record carrier 7, and the transport motor 19 performs tracking by scanning the light beam 2. 17 is driven so that the driving voltage becomes zero on average. switch 22
is opened and closed by an inverting circuit 23, but its opening and closing operation is completely opposite to that of switches 13 and 14. A is the synchronization pulse input terminal for interlacing scanning (hereinafter referred to as jumping) of the track.
A is an output terminal where the outputs of the amplifiers 10a and 10b are summed by a 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. The jumping voltage generation circuit 27 uses the output of the jumping command circuit 26 to
A jumping voltage is generated to drive the tracking element 17 via the switch 22 and the drive circuit 16. 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 designated track. Based on this pulse, the jumping command circuit 26 outputs a jumping stop command, and the switch is activated. 13 and switch 14 are closed, tracking control is applied, and switch 22 is closed.
to open. The jumping stop pulse generation circuit 25 will be explained with reference to FIG. sum circuit 24
The output terminal A is inputted to an envelope detection circuit 31, and further inputted 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 the matching circuit 36, and when the outputs of the setting circuit 35 and the counting circuit 34 become equal, the matching circuit 36 outputs the output terminal U. A jumping stop pulse is generated and 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 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 the input terminal E,
At the same time that the pulse generation circuit 41 generates a pulse, the triangular wave generation circuit 42 generates a voltage y=at. t is the time from when the jumping command is input to the input terminal E 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 the input terminal E. The outputs of the pulse generating circuit 41 and the triangular wave generating circuit 42 are combined by a combining circuit 43, and the signal at the output terminal O is inputted 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 can generally be approximated by a quadratic form, and the transfer function is G(s)=Aω ² _o /(S ² +2ω _o S+ω ² _o ) It can be expressed as
A is the sensitivity including the optical system, the damping coefficient, ω _o is the natural vibration angular frequency, and S is the Laplace operator.
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 _I (s)=(x/Aω ² _o )×(1+2ω _o /S+ω ² _o /S ²
)
Then, by inverse Laplace transform, L ^-1 [V(s)] = (x/Aω ² _o ) δ(t) + (2x/Aω _o )
It becomes U(t)+x/At. x is the velocity of the light beam 2 on the record carrier 7, δ(t) is the delta function, U(t)
is a 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 C, 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 for determining the direction of jumping, and it operates the switch 57 or switch 58, and both switches 57,
58 to drive the tracking element 17 via the drive circuit 1+, and at the same time, the output terminal of the jumping command circuit 26 drives the switches 13 and 1.
4 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 terminal K.

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.

Furthermore, 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 terminal K (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. Further, by holding the tracking drive voltage just before jumping and adding it to the jumping voltage, even more stable jumping can be performed. As the jumping synchronization pulse input terminal 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 is also applicable to a magnetic reproducing device that uses a magnetic material as a recording medium, a capacitive reproducing device that uses a recording medium that records a signal by changing the capacitance due to unevenness, etc. Needless to say, it can also be used.

Effects of the Invention The present invention disables the control means for controlling the first and second moving means during track interlacing scanning, and transmits a scanning signal to only the first moving means for instantaneously performing track interlacing scanning. In addition, since track interlacing scanning is performed, the second moving means is not driven by the scanning signal, and therefore extremely stable track interlacing scanning can be performed.

[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, 1
3, 14, 22... Switch, 15... Compensation circuit, 16, 21... Drive circuit, 17... Tracking element, 18... Electric motor, 19... Transfer motor, 20... Filter, 23... Inverting circuit ,2
4... Sum circuit, 25... Jumping stop pulse generation circuit, 26... Jumping command circuit, 27
...Jumping voltage generation circuit.

Claims (1)

[Claims] 1 converting means for reproducing a signal recorded on a record carrier; a first converting means for reproducing the signal recorded on the record carrier;
a second moving means that moves the scanning position across a track over a wider range than the first moving means, and detecting a positional deviation between the track on the record carrier and the scanning position. positional deviation detection means; first control means for controlling the first moving means so that the scanning position is located on the track by driving the first moving means in response to a signal from the positional deviation detection means; and the positional deviation detection means. a second control means for controlling the second moving means so that the scanning position is located on the track in response to a signal from the means; and disabling the first and second control means. scanning signal generating means for generating a signal for inter-track scanning to direct the scanning position to a desired track; and the opening/closing means disabling the first and second control means. A track interlacing scanning device comprising: track interlacing scanning means for applying a signal from the scanning signal generating means to the first moving means to perform track interlacing scanning.