JPH0632173B2 - Playback device - Google Patents

Description

The present invention relates to a conversion means for reproducing a signal from a recording track (hereinafter referred to as a track) of a signal recorded on a record carrier, and a scanning position of the conversion means. 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 / closing a control loop of the control means. The present invention relates to a reproducing apparatus having a function of instantaneously jumping scanning to a neighboring track at the scanning position of the means.

2. Description of the Related Art As a reproducing apparatus of this type, there is an optical reproducing apparatus. This apparatus converges a light beam generated from a light source onto a disk-shaped record carrier to form a concentric or spiral shape on the record carrier. The light beam is controlled so as to be positioned on the track recorded on, and the light beam is detected by detecting the reflected light reflected from the record carrier or the transmitted light transmitted through the record carrier by the photodetector. It is a thing. As the light source, a He-Ne laser or a semiconductor laser is generally used, and an audio signal or an image and an audio signal are recorded on the record carrier by unevenness or light and shade. Track width is about 1
The light beam is narrowed down to about 1 μm for high density recording with a track pitch of about 2 μm and a track pitch of about 2 μm. Therefore, it is necessary to use a converging lens with a large numerical aperture and a short focal depth for converging the light beam. Focus control is performed in order to always irradiate the narrowed light beam on the record carrier, but the focus control is not directly related to the present invention, and therefore detailed description thereof will be omitted.

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

In order to perform this special reproduction, it is necessary to instantaneously jump over and scan from the track on which the light beam on the record carrier is scanning to the adjacent track. The tracking control for controlling the scanning on the track is opened, the positive rectangular pulse and the negative rectangular pulse are applied to the tracking element, and then the tracking control is closed again (Japanese Patent Publication No. 52-50098). ).

Problems to be Solved by the Invention In the above-mentioned conventional method, it is extremely difficult to perform interlaced scanning of two or more tracks, and when there is eccentricity or track pitch unevenness, one interlaced scanning is performed. Those that do have a defect that the probability is low and they are unstable.

In view of this point, the present invention is to provide an apparatus capable of reliably and stably performing interlaced scanning of not only one track but also many tracks.

Means for Solving the Problems In order to solve the above problems, the present invention relates to a reproducing apparatus, a converting means for reproducing a signal recorded on a record carrier, a frequency characteristic having a natural vibration angular frequency ω _n , and converting The scanning moving means for moving the scanning position of the means in a direction substantially perpendicular to the track direction, the positional deviation detecting means for detecting the positional deviation between the scanning position of the converting means and the track, and the scanning moving means in response to the signal of the positional deviation detecting means. The control means is driven to control so that the scanning position of the conversion means always scans the track, and the track jump command means for outputting signals for starting and stopping the track jump.

Further, in this configuration, the control means is inactivated by the track jump start signal, and a signal which gradually increases with time is added to the scan moving means to drive the scan moving means to perform the track jump scanning. Then, stop the track jump scanning by the track jump stop signal,
Moreover, the control means is activated again.

According to the present invention, the scanning position of the converting means is moved at a substantially constant speed to perform the interlaced scanning with the above-described configuration. Therefore, the scanning position of the converting means comes on a desired track and the signal of the stop signal generating means is sent. When added to the scanning movement means, the movement speed of the scanning position of the conversion means becomes substantially zero, the pulling-in of the control means is very stable, and accurate and stable interlaced scanning can be performed.

Embodiments The present invention will be described in detail below with reference to the drawings. The same numbers are used for the same numbers in the description of the drawings.

FIG. 1 shows an embodiment of the device of the present invention. The light beam 2 generated from the light source 1 passes through the intermediate lens 3 and the semitransparent mirror 4, and is changed in direction by the total reflection mirror 5, and the converging lens 6
Are converged on the record carrier 7. The reflected light 8 of the light beam 2 reflected by the record carrier 7 passes through the converging lens 6 again, is changed in direction by the total reflection mirror 5 and the semitransparent mirror 4, and is received by the two-division photodetector 9. The respective outputs of the photodetector 9 are amplified by the amplifiers 10a and 10b, detected by the envelope detection circuits 11a and 11b, and the differential amplifier 12 obtains the difference signals of the envelope detection circuits 11a and 11b. Switch 1
Reference numerals 3 and 14 are for opening and closing the tracking control, and are opened and closed simultaneously in conjunction with each other. 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 switch 13, the compensation circuit 15, the switch 14 and the drive circuit 16. The total reflection mirror 5 is attached to a tracking element 17, and the tracking element 17 allows the record carrier 7 to be attached.
The light beam 2 focused above is scanned in a direction perpendicular to the track 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 transfer electric motor 19 in a direction perpendicular to the track direction on the record carrier 7. The transfer motor 19 receives the signal from the compensation circuit 15 as a filter circuit 20 and a drive circuit 21.
Is applied through the switch 13, and the transfer motor 19 is connected to the tracking element 1 in the state where the switch 13 is short-circuited.
It is driven so that the movement of 7 becomes zero on average.

The relationship between the tracking element 17 and the transfer motor 19 is that the tracking element 17 scans the light beam 2 against a sudden displacement such as eccentricity of the track on the record carrier 7 to perform tracking, and the drive voltage of the tracking element 17 is increased. The transfer motor 19 is driven so that the average value becomes zero. The switch 22 is opened / closed by an inverting circuit 23, but the opening / closing operation is completely opposite to that of the switches 13 and 14.
(A) is a sync pulse input for interlaced scanning (hereinafter referred to as jumping) of the track, and (A) is an amplifier 1
It is an output obtained by adding the outputs of 0a and 10b by the summing circuit 24. The jumping stop pulse generation circuit 25 outputs a pulse for stopping jumping after confirming that the light beam 2 crosses the track on the record carrier 7 and is on the specified track from the output of the summing circuit 24. The jumping command circuit 26 outputs a jumping command by the jumping synchronization pulse, and outputs a jumping stop command by the output of the jumping stop pulse generation circuit 25. The jumping voltage generation circuit 27 generates a jumping voltage from the output of the jumping command circuit 26, passes through the switch 22 and the drive circuit 16, and the tracking element 17
To drive. Further, the jumping process will be described in detail.

Switch 1 when not jumping
3 and 14 are closed and switch 22 is open.
Therefore, tracking control is applied. In this state
When the jumping synchronization pulse is input to (a), the jumping command circuit 26 outputs a jumping command, the switches 13 and 14 are opened, the tracking control is opened, and the switch 22 is closed. 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 the total reflection mirror 5 attached to the tracking element 17 in the direction perpendicular to the track direction on the record carrier 7 and crosses the track.
The jumping stop pulse generation circuit 25 generates a jumping stop pulse by confirming that the light beam 2 crosses the track and is on the designated track, and the jumping command circuit 26 outputs the jumping stop command by the pulse, and the jumping stop circuit 26 outputs the jumping stop command. The switch 14 is closed, tracking control is applied, and the switch 22 is opened. Second
The jumping stop pulse generation circuit 25 will be described with reference to the drawings. The output (a) of the sum circuit 24 is input to the envelope detection circuit 31, and further to the counting circuit 34 via the comparison circuit 32 and the waveform shaping circuit 33. The output of the setting circuit 35 for setting the number of jumping lines and the counting circuit 34
Is 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 generates a jumping stop pulse and the counting circuit 34
To reset. The relationship of signals from the summing circuit 24 to the waveform shaping circuit 33 will be described with reference to FIG. a is the light beam 2
Is the output of the sum circuit 24 when crossing a 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 comparison circuit 32 has a hysteresis in order to prevent malfunction. The waveform shaping circuit 33 is provided to prevent malfunction, and the output of the comparison circuit 32 can be directly input to the counting circuit 34. Further, instead of envelope detection of the output of the sum circuit 24 by the envelope detection circuit 31, either one of the outputs of the envelope detection circuits 11a and 11b or the sum signal can be used.

The jumping voltage generating circuit 27 will be described with reference to FIG. When a jumping command is input from the jumping command circuit 26 to (c), a pulse is generated by the pulse generation circuit 41 and at the same time y = a by the triangular wave generation circuit 42.
A voltage of t is generated. t is the time from when the jumping command is input to (c) from the jumping command circuit, and a is the gradient of the voltage y generated from the triangular wave generation 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 the combining circuit 43, and the output (D) is the switch 22.
To the tracking element 17 via the drive circuit 16.

The jumping voltage for stabilizing the jumping will be described. When jumping, record carrier 7
It is necessary for the tracking control system to be retractable with respect to the relative speed of the moving speed of the upper light beam 2 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 retract, and in the case of a relative speed that causes a limit, the tracking control system does not pull in a predetermined detected track but pulls in another track that has gone too far. In order to stably pull in, it is desirable to add a reverse pulse for braking to make the relative moving speed of the light beam 2 and the track equal to or lower than the pulling speed of the tracking control system 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 velocity, it is necessary to change the shape of the reverse pulse according to the velocity of the light beam 2. Therefore, a means for detecting the speed of the light beam 2 and the like is required, and the apparatus becomes very complicated. Therefore, if the light beam 2 moves at a constant speed and the reverse pulse always has a constant shape, an extremely simple device can be obtained.

The tracking element 17 includes 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) is Can be expressed as S is the Laplace operator, A is the sensitivity including the optical system, Is the damping coefficient, and ω _n is the natural vibration angular frequency. In order to move the light beam 2 at a constant velocity using such a tracking element 17, the voltage applied to the tracking element 17 is Then, if this is inverse Laplace transformed, Becomes K is the velocity of the light beam 2 on the record carrier 7, δ (t)
Is a delta function and U (t) is a single step function.

From the above, if the voltage input to the tracking element 17 is a combined voltage of a pulse voltage, a step voltage, and a lamp voltage, the light beam 2 can be moved at a substantially constant speed. Since ω _n generally uses about 2π × 30 or more, the pulse voltage becomes extremely small, and even if omitted, the light beam 2 can be moved at a substantially constant speed.

The above will be described with reference to FIG. The summing circuit 51 pressures the combined voltage of the outputs of the pulse generating circuit 52, the step voltage generating circuit 53, the ramp voltage generating circuit 54, and the reverse pulse generating circuit 55, and inputs it to the inverting circuit 56 and the switch 57. The jumping command circuit 26 operates by the jumping synchronization pulse input (a) and the jumping stop pulse input (e), and the pulse generation circuit 52 and the step voltage generation circuit 5
3. The ramp voltage generation circuit 54 starts its operation at the same time as the jumping synchronization pulse, and the reverse pulse generation circuit 55 starts its operation at the same time as the jumping stop pulse. The input (f) is an input terminal for determining the direction of jumping. With this, the switch 57 or the switch 58 is operated, and the outputs (ki) of both switches 57 and 58 are transmitted through the drive circuit 16 to the tracking element 17. At the same time, the switches 13 and 14 are operated by the output (K) of the jumping command circuit 26 to perform jumping.

The above operation will be described in more detail with reference to FIG. Sixth
The drawing shows the case where the setting circuit 35 is set to jump two lines, a is the output of the sum circuit 24, b is the jumping synchronization pulse, and c is the light beam 2 on the record carrier 7.
Is an output of a waveform shaping circuit 33 that generates a pulse at the same time as crossing a track, d is an output of a matching circuit 36 that generates a jumping stop pulse, and e is a jumping command circuit 2.
The output of 6 and f are the waveforms of the jumping voltage output (g).

The time relationship between the waveform a and the waveform c is such that a signal (waveform c) across the track is generated from the moment the light beam 2 on the record carrier 7 enters the track to the moment when it reaches the center of the track, and jumping is performed. It is desirable to stop the jumper, but it is also possible to stop the jumping by generating it from the moment when it reaches the center of the truck to the moment when it leaves the truck.

The time relationship between the waveforms e and f is the jumping voltage output
(G) The tracking control can be closed after the reverse pulse of (waveform f) is output.

Switches 13 and 14 for opening and closing the tracking control
Do not open and close at the same time, and switch 1
3 may be opened and closed. Although it is possible to use only the switch 14, if the loop gain of the tracking control system is made large, the circuit may be saturated and a non-linear portion may be generated when the tracking control is opened, and pull-in may not be stable. Further, by holding the tracking drive voltage on the verge of jumping and synergizing with the jumping voltage, more stable jumping can be performed.
As the jumping sync pulse input (a), a vertical sync signal of the image signal or a divided version thereof can be used.

Although the present invention has been described by taking the optical reproducing device as an example, the present invention is also applied to a magnetic reproducing device using a magnetic material as a record carrier, a capacitive reproducing device using a record carrier in which a signal is recorded by a capacitance change due to unevenness. It goes without saying that you can do it.

Effects of the Invention As described above, according to the present invention, a still image (still image), a slow motion image, a quick motion image, a back motion image, or the like is reproduced at a time different from the time recorded on the record carrier. The special reproduction image can be stably obtained. Also record still images in concentric circles,
The present invention can also be used in a search device for the purpose of instantly searching and reproducing a desired still image.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a concrete configuration diagram of the jumping stop pulse generating circuit 25 of FIG. 1, and FIG. 3 is an explanatory waveform when a light beam 2 crosses a track. 4 and FIG. 4 are concrete configuration diagrams of the jumping voltage generating circuit 27 of FIG. 1, FIG. 5 is a block diagram showing one embodiment of the jumping voltage generating circuit, and FIG. 6 is an explanatory waveform diagram of each part of FIG. Is. 1 ... Light source, 5 ... Total reflection mirror, 7 ... Record carrier, 9
...... 2 split photodetectors, 11a, 11b ...... Envelope detection circuit, 12 ...... Differential amplifier, 15 ...... Compensation circuit, 1
6, 21 ... Driving circuit, 17 ... Tracking element, 1
8 ... 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.

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Noboru Wakami 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Yasuhiro Goto, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Kazuharu Shirakami 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-52-152704 (JP, A) JP-A-52-57803 (JP, A)

Claims (4)

[Claims] 1. A converting means for reproducing a signal recorded on a record carrier; and a scanning for moving a scanning position of the converting means in a direction substantially perpendicular to a track direction, the scanning characteristic having a natural vibration angular frequency ω _n. A moving unit, a position shift detecting unit for detecting a position shift between the scanning position of the converting unit and the track, and a driving unit for driving the scanning moving unit according to a signal of the position shift detecting unit so that the scanning position of the converting unit is changed. It has a control means for controlling to always scan on the track and a track jump command means for outputting a signal for starting and stopping the track jump, and the control means is deactivated by the track jump start signal, and gradually over time. A signal that increases to the above-mentioned scanning moving means is driven to perform the track jump scanning, and the track jump stop signal is generated. Track interlace scanning is stopped, and the reproduction apparatus characterized by operating the control means. 2. A track jumping scan is performed by driving a scan moving means in addition to a scan moving means with an addition signal of a pulse-like signal generated at the start of the track jump scanning and a signal increasing in a predetermined relationship with time. The reproducing apparatus according to claim 1, wherein: 3. A track moving drive unit is driven by adding a pulse-like signal generated at the start of the track interlace scanning, a step-like signal, and an addition signal of a signal increasing with a predetermined relationship with time to the track moving unit. The reproducing apparatus according to claim 1, wherein interlaced scanning is performed. 4. A reproducing apparatus according to claim 1, wherein a pulse jump signal is applied to the scanning moving means to stop the scanning moving means by the track jump stop signal.