JPH03224173A - Both disk side reproducing device - Google Patents

Abstract

PURPOSE:To rapidly stop a spindle motor at the time of stopping it by detecting a frequency change of an FG pulse in the midst of changing a signal reproducing picture by a pickup and discriminating the rotational direction. CONSTITUTION:The spindle motor 3 is mounted with an FG detector 31 for detecting magnetically a rotating speed of the motor 3 of its own and outputting as the FG pulse, and the obtained FG pulse is shaped in wave by an FG shaping circuit 32 and afterward inputted to a servo microcomputer 33. Then, a change of a rotation detecting signal at the time of changing the signal reproducing picture by the pickup 4 is detected to discriminate the rotational direction of the spindle motor 3 at the time of reproducing the disk. By this method, the detection of the rotational direction of the spindle motor 3 is always accurately recognized, and the time required for a stopping operation is shortened.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a device for reproducing signals from a disc on which information is recorded on the front and back screens, and particularly relates to a device for reproducing signals from a disc on which information is recorded on the front and back screens. The present invention relates to a device for detecting.

(b) Conventional technology In general optical video disc playback devices,
When reproducing signals recorded on both sides of an optical disc, it is necessary to remove the disc from the device once signal reproduction on one side is completed, turn the disc over, and load it into the device again to reproduce the signal side on the other side. . Therefore, there is a problem that the operation is extremely complicated.

In response to this, a device has been proposed that can reproduce signals continuously from both signal sides without turning the disc over.

For example, Japanese Patent Application Laid-Open No. 63-288476 (611B2
1102) includes upper and lower linear guide portions that guide the linear movement of the movable base when a single pickup is placed on the movable base and the front and back surfaces of the disc are reproduced;
By providing a U-shaped guide means consisting of an arc-shaped guide section that connects these two guide sections and guides the movement of the movable base from the upper side to the lower linear guide section or vice versa,
Techniques have been proposed for reproducing a desired disc surface using a single pickup.

By the way, normally, in order to stop a spindle motor that is being driven, a braking force is applied to the spindle motor by applying a voltage of opposite polarity to the drive voltage to the spindle motor.

On the other hand, in the conventional disk double-sided playback device, the direction of rotation of the disk, that is, the direction of rotation of the spindle motor, must be changed depending on whether the surface being played back by the pickup is the front or back side. If a voltage of polarity is applied, whether or not it will produce a braking force will vary depending on the reproducing surface.

Therefore, as a conventional motor stopping procedure, try (i) applying a voltage with a polarity that rotates the spindle motor clockwise.

(ii) Detect the FG pulse of the motor at this time, calculate the rotation speed from the frequency of this FG pulse, and if the speed increases due to the voltage application in (i), the rotation direction of the spindle motor is clockwise. If the speed decreases, the rotation direction is determined to be counterclockwise.

(iii) Since the rotation direction has been determined by (i) and (ii), a voltage is again applied with a polarity opposite to the rotation direction to stop the motor.

becomes.

(c) Problems to be Solved by the Invention As mentioned above, the conventional technology does not have a function to detect the rotation direction, so it takes a long time before the spindle motor stops, such as applying a clockwise voltage to detect the rotation direction. It will require.

In addition, during the switching operation of the reproducing surface, that is, during the transition period when the rotation of the spindle motor is substantially reversed, it becomes extremely difficult to determine the true direction of rotation, and what polarity of voltage should be applied to the motor to brake the motor. It is difficult to judge whether the force can be applied, and it takes time to stop the motor.

(d) Means for Solving the Problems The present invention detects the change in the frequency of the FG pulse during the change of the signal reproducing surface by the pickup to determine the rotation direction, and based on the result of this determination, the brake It is characterized by determining the polarity of the voltage.

(E) Function Since the present invention is configured as described above, even if the pickup moves to perform playback of each side of the disc,
Since the direction of rotation of the motor is always recognized, there is no need to detect the direction of rotation of the motor immediately before the stop operation, and the stop operation can be performed instantly. Further, even when the spindle motor is stopped in the middle of the reproducing surface switching operation, the stopped state can be quickly achieved.

(f) Example An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 2 to 4 are diagrams showing the pickup transport mechanism of the optical video disc player according to this embodiment.

(1) is a turntable that is rotationally driven by a spindle motor (3), and a disk (9) is clamped to this turntable-L and rotates together with the turntable. Information such as audio signals and video signals is optically recorded on the front surface (lower surface in the figure) and back surface (upper surface in the figure) of the disk (9) from the inner circumference to the outer circumference.

(6) is the pickup (4) and field motor (5)
It is a support base that supports the pinion, and on both sides, when driven by the feed motor (5) via the drive force transmitter t* (not shown), the pinion (7a) (7b) and the pinion coaxial It has guide rollers (8a) (8b) arranged in Guide holes (12) are formed in the chassis (49a) (49b) into which straight guide poles (lla) (llb) arranged to extend in the radial direction of the disk (9) can fit. There is.

(17) and (18) are a pair of guide blocks that guide the movement of the support base (6), with upper linear parts (17a) and (18a) extending above the disk (9) and It is composed of extending lower linear parts (17c) (18c) and connecting parts (17b) (18b) that connect the double-sided linear parts (17a) (18a), (17c) (18c), and are opposed to each other. Racks (19) (20) and guide grooves (21) are provided on the inner peripheral surface.
)(22) are formed. Pinio”y (7a) (
7b) are engaged with the racks (19) and (20), and the guide rollers (8a) and (8b) are fitted into the guide grooves (21 and 22), respectively.
), the support base (6) moves on the guide holes (17) and (18), and while moving on the lower straight parts (17c) and (18c), the support base (6) moves on the guide holes (12). A guide ball (llb) is fitted in and guided in a straight line, making it possible to optically scan the lower surface of the distar (9), and guided in the guide hole (12) while moving on the upper straight part (17a) (18a). The ball (lla) is fitted and linearly guided to enable optical scanning of the upper surface, and the connecting part (lla)
7b) By moving Dsb), continuous scanning of the lower and upper surfaces is possible.

The spindle motor (3) is equipped with a well-known FG that magnetically detects the rotational speed of the motor itself and outputs it as FG pulses.
A detector (31) is attached. The frequency of this FG pulse is proportional to the rotational speed of the spindle motor.

FIG. 5 shows a block diagram of the spindle motor drive section, and the FG pulse obtained from the FG detector (31) is
After being waveform-shaped by the FG shaping circuit (32), it is input to a servo microcomputer (33) (servo microcomputer).

During normal playback, the servo microcomputer (33) uses the PWM output, which is the drive signal of the spindle motor (3), as a motor control signal so that the frequency of the horizontal synchronization signal played from the disk (9) becomes the reference frequency. It also has a function of always monitoring the frequency of the above-mentioned FG pulse and outputting a PWM output for braking in consideration of the polarity of the drive signal as a motor control signal.

The PWM output from the servo microcomputer (33) is supplied to the drive circuit (35) of the spindle motor (3) after the transmission frequency is compensated by the phase compensation circuit (34).
Used for drive control of the spindle motor (3).

The frequency of the FG pulse, that is, the rotational speed of the spindle motor (3) varies greatly depending on when the upper and lower surfaces of the disk (9) are being reproduced and during the reproduction surface switching operation. That is, as shown in FIG. 1, the support base (6)
(18c) and during the period (Ll) in which the pickup (4) is reproducing the lower surface of the disk (9), the rotation direction is clockwise, the frequency of the FG pulse is approximately stable, and jitter Only variations in the components occur. Similarly, the support base (6) is
a) Move the pickup (4) to the disc (9)
Even during the period in which the upper surface of the disk is being reproduced, the rotational direction is in a substantially stable state in the counterclockwise direction, contrary to the above-mentioned case, as in the period (L5).

Note that the frequency of the detected FG pulse cannot take into account the rotational direction of the motor, and merely indicates the absolute value of the rotational speed of the motor.

Next, the support base (6) connects the connecting parts (17b) (18b)
When moving from the lower linear part (17c) (18c) to the upper linear part (17a) (ISa) through A voltage (Vo) with a polarity that rotates the motor in the clockwise direction is applied, and as a result, a braking force is applied to the motor that was rotating clockwise during bottom surface regeneration. Accordingly, while the support base (6) is moving through the connecting parts (17b) (1, 8b), the frequency fluctuation of the FG pulse tends to decrease in the period (L2), and the applied voltage with the polarity in the counterclockwise direction (Vo) acts as a braking force on the motor, which is still rotating clockwise, and will be gradually decelerated. Then, when the motor momentarily stops at timing (T,), the applied voltage (Vo) causes the motor (3) to rotate counterclockwise, and the frequency of the FG pulse changes to period (L4). As shown, there is an upward trend, and the timing (T
When a frequency suitable for top surface reproduction is reached in step 4), a stable state is reached.

If the disc to be played is a CLV (Constant Linear Velocity) disc, the rotation speed of the spindle motor (3) changes depending on the pick-up playback position in the disc radial direction.
During upper and lower surface regeneration, the frequency of the FG pulse is not necessarily maintained in a stable state as shown in Figure 1, but the amount of fluctuation at this time is extremely small compared to the amount of fluctuation during periods (L2) and (L4) and can be ignored. This is as much as possible.

Next, the operation of monitoring the frequency fluctuation of the FG pulse by the servo microcomputer (33) will be explained using an example when the reproduction surface is switched from the bottom surface to the top surface. In this device, in the initial state after the disc is loaded, the pick amplifier (4) is in the bottom playable position, and the disc is configured to rotate clockwise unconditionally.

When bottom surface regeneration is executed from the initial state and a top surface regeneration command is issued at timing (TO), the spindle motor (3) is set to rotate clockwise in advance in this initial state, so the command is issued at the same time. Apply a voltage that causes counterclockwise rotation. As a result, the frequency of the FG pulse shows a downward trend and then an upward trend.

In this downward trend, the rotational direction is the same as during bottom surface regeneration, but the rotational speed decreases, and since the current applied to the motor is acting as a braking force, the spindle motor (3) stops at this point. When a command is suddenly issued, braking force is applied by maintaining the polarity of the applied voltage as it is.

When the FG frequency shows an increasing trend, the rotation direction is the same as during top surface regeneration, but the rotation speed increases, so the current applied voltage is acting as a driving force, so at this point the spindle motor When the stop command (3) is issued, the polarity of the applied voltage is reversed and a clockwise rotational force is applied, thereby applying a braking force.

Further, after passing through the negative, downward and upward trends, the switching of the reproduction surface is completed and the top surface reproduction is performed.

Therefore, from now on, it is always recognized that top surface regeneration is being performed until the frequency of the FG pulse changes significantly again, and when a stop command is issued under this situation, the polarity that immediately causes clockwise rotation is recognized. The applied voltage is generated to apply braking force.

Also when the playback surface moves from the top surface of the disc to the bottom surface, the first
As shown in the figure, the frequency of the FG pulse goes through a downward and upward trend, and in response to a stop command during playback surface switching operation, the voltage applied to the motor changes depending on whether the frequency is downward or upward. Can be stopped quickly by changing polarity.

Furthermore, after this downward and upward fluctuation has passed once, it is determined that the regeneration surface has moved to the lower surface side again, and in response to a stop command, an applied voltage with a polarity that causes counterclockwise rotation is applied to the motor as a brake. If it does, it will immediately stop.

Incidentally, in FIG. 1, the detected FG pulse contains a jitter component, and the frequency always slightly fluctuates. Also,
To check whether the spindle motor (3) has stopped, press F.
This is done depending on whether the period of the G pulse is zero or not.

Furthermore, when considering the effect of jitter bite, the steps (i), (ii), and (iii) described in the conventional example are executed only during the period (L3) when the frequency of the FG pulse is extremely low, and the rotational direction is changed. It is also possible to improve the reliability of detection.
I can do it.

(G) Effects of the Invention As described above, according to the present invention, it is possible to always accurately detect the rotational direction of the spindle motor during playback of any side of the disk and during the transition period of switching the playback side. . Further, the time required for stopping and moving based on the detection result of the rotation direction is significantly reduced.

[Brief explanation of drawings]

The drawings all relate to one embodiment of the present invention; FIG. 1 is a diagram explaining the change in the frequency of the FG pulse, FIG. 2 is a diagram explaining the movement of the pickup, and FIGS. 3 and 1 are the pickup moving mechanism. 5 is a front view of the circuit, and FIG. 5 is a schematic diagram of the circuit. (9)...disc, (4)...pi7qua lp,
(3)...Spindle motor, (31)...FG detector, (33)...Microcomputer for servo

Claims (2)

[Claims] (1) A pickup that selectively reproduces signals from either side of both surfaces of the disk, a spindle motor that rotates the disk forward or backward depending on the surface from which the signal is reproduced by the pickup, and a rotation speed proportional to the rotation speed of the spindle motor. a rotation state detection means for emitting a rotation detection signal at a frequency of a given frequency; and a determination means for detecting a change in the rotation detection signal when the signal reproduction surface by the pickup changes, and determining the direction of rotation of the spindle motor during disk reproduction. A disc double-sided playback device comprising: (2) The disk duplex reproducing apparatus according to item 1, further comprising a polarity determining means for determining the polarity of the brake voltage applied to the spindle motor in accordance with the output of the determining means.