JPH07220411A - Disk reproducing device - Google Patents

Abstract

PURPOSE:To efficiently output an adjustment signal by absorbing the vibration of a disk during rotation by rotating and driving the disk while a drive belt is wound around different peripheral edges of the disk. CONSTITUTION:Since drive belts 11 and 21 are extended In parallel, each winding part is set at 180 degrees for a disk 50, thus canceling the side pressure to the rotary shaft of a turntable 4 due to the tension of the drive belts 11 and 21, where CLV signal is output from a terminal 64 of a microcomputer 60 so that motors 35 and 45 are rotated counterclockwise and the disk 50 starts rotating clockwise. At the start of the rotation of a disk 5, the rotary position of the disk 50 is made stationary at a specific position, laser beams discharged from an objective lens 3 are focused on the recording surface of the disk 50 for tracking the track of the disk 50. Therefore, both servo loops are turned on and an adjustment signal is started so that the disk 50 rotates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk rotation drive device for rotating a disk in order to reproduce information from the disk such as a compact disk.

[0002]

2. Description of the Related Art The applicant of the present application has proposed, as Japanese Patent Application No. 5-2147033, a technique in which a drive belt is wound around the periphery of a disk and the drive belt is driven to rotate. Also, by applying this technology, an apparatus for reading information recorded on a disc by a fixedly arranged optical pickup while moving the disc in the radial direction when the disc is rotated by such a belt as Japanese Patent Application No. 5-316085. Is proposed.

[0003]

However, in the above-mentioned prior art, the tension of the drive belt formed of rubber may be applied as a lateral pressure to the rotation axis of the disk, and stable rotation may not be achieved. Further, in Japanese Patent Application No. 5-316085, since a drive mechanism for rotationally driving the disk and a drive mechanism for moving the disk in the radial direction are required, the mechanism is complicated and the cost is disadvantageous. there were.

[0004]

Means for Solving the Problems As a means for solving the above-mentioned problems, the present invention comprises a pair of drive belts wound around different peripheral edges of a disk at required angles.
It comprises a drive source for driving a pair of drive belts, and a reproducing means for reproducing information recorded on the disc.

In particular, the reproducing means is fixedly arranged without moving in the radial direction of the disc. In addition, by controlling the drive source, the disc is rotated at a required number of revolutions, and at the same time, a control unit that changes the respective speeds of the pair of drive belts in order to move the disc in the radial direction with respect to the reproducing unit is provided. Including.

Further, the present invention comprises a turntable on which a disc is mounted and which is movable with respect to the chassis.
Further, the pair of drive belts are respectively stretched between the drive pulley and the driven pulley, and the stretching directions are substantially parallel to each other.
Further, they can be moved in the directions of approaching or separating from each other.

[0007]

The pair of drive belts are wound around different peripheral edges of the disc to rotate the disc. In this case, the disc is rotated by the control means at the required number of rotations and is moved in the radial direction with respect to the reproducing means. Further, the pair of drive belts are stretched so as to be substantially parallel to each other, and move in a direction in which they approach or separate from each other.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a plan view of a disk reproducing apparatus before a disk is mounted, and FIG. 2 is a right side view with a belt omitted. The optical pickup 2 including the objective lens 3 is fixedly arranged on the chassis 1. Further, the turntable 4 on which the disc having the center hole is mounted is
It is rotatably supported by the table support section 5. In FIG. 1, the turntable 4 is located closest to the optical pickup 2.

The turntable support portion 5 is linearly movable by a pair of parallel guide shafts 6 fixedly arranged on the chassis. Further, in order to detect the position of the turntable 4, the potentiometer 7 whose output voltage changes according to the radial position of the turntable supporting portion 5 is detected.
Are arranged over the moving range of the turntable supporting portion 5.

A pair of endless drive belts 11 and 21 made of rubber are provided to rotate and drive a disk having spiral tracks. The left drive belt 11 is wound around a drive pulley 12 and a driven pulley 13, and the right drive belt 21 is wound around a drive pulley 22 and a driven pulley 23.

The line connecting the rotating shafts 14 and 15 of the drive pulley 12 and the driven pulley 13 and the drive pulley, respectively.
The rotary shafts 24 and 25 of the pulley 22 and the driven pulley 23, respectively.
It is said that it is parallel to the line that connects and. Therefore, the stretching directions of the drive belts 11 and 21 are also parallel.

FIG. 4 is a sectional view of the drive pulley 12. The drive pulley 12 has a V-shaped groove 37 formed on the periphery thereof, and the drive belt 11 is wound around the groove 37. The drive belt 11 has a V-shaped cross section, and the drive belt 11 is hung between the drive pulley 12 and the driven pulley 13 to form a V-shaped groove 38 on the outer circumference of the closed loop. To form. Further, on the inner circumference of this closed loop, the drive belt 1
The reference numeral 1 forms a convex portion having a triangular cross section, and this concave portion engages with the respective grooves of the driving pulleys 12 and 22 and the driven pulleys 13 and 23. The drive pulley 22 and the driven pulley 1
Reference numerals 3 and 23 have the same shape as the drive pulley 12, and the drive belt 21 has the same shape as the drive belt 11.

The drive pulleys 12 and 22 and the driven pulleys 13 and 23 are movable with respect to the chassis 1 so that the drive belts 11 and 21 can move in the directions in which they approach each other. The moving mechanism will be described. FIG. 3 is a bottom view of the disc reproducing apparatus shown in FIG. 1, in which the rotating shafts 14 of the drive pulleys 12 and 22 and the driven pulleys 13 and 23,
24, 15, 25 are cylindrical bearings 16, 26, 17, 2
The bearings 16 and 17 are axially supported in the slide plate 31, and the bearings 26 and 27 are slide plates 41.
It is fixedly arranged at both ends of each.

The pair of rotating arms 32, 42 are pivotally supported at their intermediate positions on the shaft 30 provided on the bottom surface of the chassis 1. Slots 33 and 34 are formed at both ends of the rotary arm 32, and the bearing 27 is inserted into the slot 33 and the bearing 16 is inserted into the slot 34, respectively. Similarly, the rotating arm 42
Long holes 43 and 44 are formed at both ends of
The bearing 17 is inserted into the long hole 43, and the bearing 26 is inserted into the long hole 44.

Slots 18, 19, 28, 29 are formed in the chassis 1 in a direction orthogonal to the extending direction of the parallel guide shaft 6, and bearings 16, 17, 26, 27 are inserted in the slots. . Therefore, the slide plates 31 and 41 are movable in parallel with each other, so that the line connecting the rotary shafts 14 and 15 of the drive pulley 12 and the driven pulley 13 and the drive pulley 22 are connected. , Each rotation shaft 2 of the driven pulley 23
The line connecting 4 and 25 is movable in the direction orthogonal to the parallel guide shaft 6 while keeping the line parallel.

The drive source 46 moves one slide plate 31, and is composed of a motor or the like (not shown). With the movement of the slide plate 31, the slide plate 41 also moves by the same amount as the movement amount of the slide plate 31. Therefore, the drive belts 11 and 21 move in the directions toward and away from each other by the same amount. Further, motors 35 and 45 are attached to the slide plates 31 and 41, respectively, and their rotation shafts are bearings 16 and 2.
6 is connected to the rotary shafts of the drive pulleys 12 and 22.

FIG. 5 is a block diagram of a drive control circuit for driving and controlling the motors 35 and 45. Based on the reproduction signal from the optical pickup 2, the microcomputer 60 performs a focus servo to move the objective lens 3 of the optical pickup 2 in the direction of approaching / distinguishing from the recording surface of the disk 50, and also the objective lens 3 is moved. In order to perform a tracking servo which moves in a direction orthogonal to the track of the disk 50, focus terminals are respectively output from the output terminals 61 and 62.
Outputs a bob signal and a tracking servo signal.

These servo signals move the objective lens 3 in a required direction via drive circuits 71 and 72, respectively. Further, a low-pass filter (hereinafter,
An LPF) 73 is connected to take out the DC component of the tracking servo signal. This DC component is input to the adding circuits 66 and 67.

The output voltage of the potentiometer 7 is the terminal 65.
Is input to the microcomputer 60 and the current position of the disk 50 is measured. A start adjustment signal is output from the output terminal 63 of the microcomputer 60 so that the output of the potentiometer 7 becomes the same voltage at the start of reproduction, that is, the rotation center of the disk 50 rotates while maintaining the specified position. To be done. This adjustment signal is input to the adding circuits 66 and 67 and added to the DC component of the tracking servo signal.

The output of the adder circuit 66 is input to the adder circuit 68. The output of the adder circuit 67 is input to the adder circuit 70 via the polarity inverting circuit 69.

From the terminal 64 of the microcomputer 60, a CLV servo signal for rotating the disk 50 on which information is recorded by CLV is output. As is well known, this servo signal rotates the disk 50 at a prescribed speed based on a phase difference signal obtained by comparing the phase of the synchronizing signal included in the reproduction signal from the optical pickup 2 with the reference clock. is there. This CLV servo signal is added to the adder circuit 6
8 and 70 are input.

The outputs of the adder circuits 68 and 70 drive the motors 35 and 45 to rotate through the motor drive circuits 74 and 75.

Therefore, during reproduction of the disc 50,
The motors 35 and 45 are controlled by both the CLV servo signal for rotating the disk 50 at a specified linear velocity and the DC component in the tracking servo signal for moving the disk 50 in the radial direction. . At the start of disk reproduction, the motors 35 and 45 are controlled by the CLV servo signal and the start adjustment signal.

The operation of the above configuration will be described. In the state shown in FIG. 1, a disk 50 having an outer diameter of 12 cm is mounted on the turntable 4. afterwards,
As the drive source 46 moves the slide plate 31 along the elongated holes 18 and 19 in the direction approaching the turntable 4, the slide plate 31 is connected to the slide plate 31 by the rotating arms 32 and 42. The plate 41 also moves in the direction of approaching the turntable 4.

Therefore, the drive belts 11 and 21 are respectively wound around different peripheral portions of the disk 50 within an angle range of about 40 degrees. Further, in order to hold the disc 50 on the turntable 4, a known clamper 51 is arranged on the upper surface of the disc 50, and a magnet (not shown) provided on the clamper 51 connects the turntable 4 to the turntable 4. The disc 50 is held between it and the clamper 51. FIG. 6 is a plan view showing this reproduction start state.

Here, since the drive belts 11 and 21 are stretched in parallel, the respective winding portions are the disc 50.
The position is 180 degrees with respect to. Therefore, the lateral pressure on the rotary shaft of the turntable 4 due to the tension of the drive belts 11 and 21 is canceled.

In this state, the microcomputer 6 shown in FIG.
By outputting the CLV signal from the terminal 64 of 0,
Rotate the motors 35 and 45 counterclockwise to move the disk 5
Start the clockwise rotation of 0. Where disk 5
At the start of the rotation of 0, the rotational position of the disk 50 is stopped at the position shown in FIG. 6, and the laser light emitted from the objective lens 3 is focused on the recording surface of the disk 50.
In addition, both tracks must be turned on in order to track the tracks on the disk 50. Therefore,
The microcomputer 60 monitors the output of the potentiometer 7 to prevent the turntable 4 from moving while the disk 50 is being moved.
A required start adjustment signal is output so that the motor rotates.

Here, the CLV signal from the terminal 64 is both input to the motors 35 and 45 in the positive phase, but the start adjustment signal is input to the motor 35 in the positive phase. On the other hand, the polarity inverting circuit 69 inputs signals to the motor 45 in reverse phase. Therefore, although the drive belts 11 and 21 are driven at the same speed at the start of the rotation of the disk 50, the disk 5 may be driven by, for example, a mechanical factor.
When the rotation center of 0 moves, the start adjustment signal is output to increase the rotation speed of one motor and decrease the rotation speed of the other motor.

For example, when the disk 50 moves upward from the position shown in FIG. 6 at the start of rotation of the disk 50, the microcomputer 60 based on the output of the potentiometer 7.
Outputs a negative start adjustment signal from its terminal 63. As a result, the speed of the drive belt 11 driven by the motor 35 is reduced, and the speed of the drive belt 21 driven by the motor 45 is increased. Therefore, it is possible to control so that the rotation center of the disc 50 does not move due to a moving force that causes the rotation center of the disc 50 to move downward in the plane of the drawing while maintaining a predetermined rotation speed.

The focus servo and the tracking servo are turned on in a state where the disk 50 is rotated while being prevented from moving in accordance with the start adjustment signal, and the focus servo causes the disk 50 to move. The objective lens 3 is moved up and down following the surface runout, and the objective lens 3 is moved in the direction orthogonal to the track of the disk 50 following the eccentricity of the disk 50 by the tracking servo.

Since the disk 50 has spiral tracks, the objective lens 3 gradually moves toward the outside of the disk 50 as a result of reproduction, and as a result, the tracking servo signal has a DC component. Appears.

This DC component is taken out by the LPF 73 and is sent to the motor 35 via the adder circuits 66 and 68 and the drive circuit 71, and also via the adder circuit 67, the polarity inverting circuit 69, the adder circuit 70 and the drive circuit 72. Applied to the motor 45. Therefore, since the voltages applied to the motors 35 and 45 in the state of being rotated only by the CLV servo signal are equal, in the motor 35, the number of rotations is increased so that the motor 45 can rotate. The voltage applied to each of the motors 35 and 45 changes so as to reduce the number of rotations thereof.

Therefore, as a result of the speed of the drive belt 11 increasing with respect to the speed of the drive belt 21, a moving force is generated in the direction in which the center of rotation of the disk 50 separates from the objective lens 3, and the turntable support portion. 5 moves upward along the parallel guide shaft 6 in the plane of FIG.

Where v is the read linear velocity of the disk,
When p is the track pitch, ri is the innermost radius in the recording range of the disk 50, rt is the read radius t seconds after ri, and rd is the radius of the disk 50, the read radius after t seconds is v.p. t = π (rt ² −ri ² ) Therefore, ∴

[Equation 1] Velocity v ₁₁ t, v ₂₁ t of each drive belt 11 and 21 after t seconds
Is

[Equation 2]

[Equation 3] The motors 35 and 45 are controlled so as to achieve this speed while the disc 50 is being reproduced.

During the reproduction, since the drive belts 11 and 21 are wound around the periphery of the disc 50, the vibration of the disc 50 generated during the rotation of the disc 50 is suppressed. Further, the cross sections of the drive belts 11 and 21 are V-shaped as shown in FIG. 4, so that the peripheral edge of the disk 50 is clamped, and the surface wobbling of the disk 50 can be prevented.

FIG. 7 is a plan view showing a state where the optical pickup 2 is reproducing the outermost peripheral position in the recording range of the disc 50. At this position, the reproduction of the disk 50 is completed, and the motor 35 is rotated clockwise and the motor 45 is rotated counterclockwise so that the drive pulleys 12 and 22 are rotated clockwise and counterclockwise, respectively. The disc 50 is rotated and moved from the position shown in FIG. 7 downward in the drawing.

The microcomputer 60 monitors the output of the potentiometer 7 and, after detecting that the disk 50 has moved to the position shown in FIG. 5, stops the rotation of the motors 35 and 45. Further, the drive sources 44 move the slide plates 31 and 41 to move the belts 11 and 21 to the positions shown in FIG. 1, and separate the drive belts 11 and 21 from the disk 50.

A case of reproducing a disk 80 having an outer diameter of 8 cm will be described with reference to FIG. 8 which is a plan view showing a reproduction start state of the disk 80 and FIG. 9 which is a bottom view thereof. When reproducing a disc 80 having an outer diameter of 8 cm and the same diameter as the disc 50 having a center hole of 12 cm,
Similarly to the above, the disk 80 is placed on the turntable 4, the clamper 51 is mounted, and then the drive source 46 moves the slide plates 31 and 41 to the positions shown in FIG. Along with this movement, the drive belts 11 and 21 move parallel to each other around the turntable 4 so as to approach each other, and the respective drive belts 11 and 21 extend over the outer circumference of the disk 80 over an angle range of about 40 degrees. Wrap around.

From this state, the motors 35 and 4 are driven as described above.
5 is rotated, and the drive pulleys 12 and 22 are rotated counterclockwise at the required number of rotations. After starting playback,
Velocity v ₁₁ t, v ₂₁ t of each drive belt 11 and 21 after t seconds
Is the same as above

[Equation 2]

As defined by the following equation, since rd is small,
When the disk 80 is rotated at the same linear velocity as the disk 50, the number of rotations of the motors 35 and 45 when rotating the disk 80 is increased.

In the above embodiment, the disc is supported by the turntable, but depending on the sectional shape and rigidity of the drive belt, for example, the disc can be stably supported only by the pair of drive belts. Is also possible.

Further, in the above embodiment, two kinds of discs having different outer diameters can be reproduced, and the drive belt can be moved in parallel so as to separate the disc from the drive belt. Alternatively, the drive belt may be wound around the peripheral edge of the disk. In this case, a mechanism for moving the drive belt is not necessary.

[0042]

According to the present invention, since the disc is rotationally driven while the drive belt is wound around different peripheral edges of the disc, it is possible to absorb the vibration of the disc during rotation and to realize stable reproduction. .

Further, according to the present invention, the reproducing means is fixedly arranged without moving in the radial direction of the disc, and a pair of drive belts for rotationally driving the disc rotate the disc and move the center of rotation of the disc. Since both can be performed by a pair of drive belts, the drive mechanism is simple and cost effective.

In this case, since the reproducing means, which is a complex of precision parts, is not moved in the radial direction of the disk, stable disk reproduction can be performed without adversely affecting the optical pickup.

[Brief description of drawings]

FIG. 1 is a plan view showing a state in which a drive belt is not wound around a disc.

FIG. 2 is a right side view of the disc reproducing device shown in FIG.

3 is a bottom view of the disc reproducing device shown in FIG. 1. FIG.

FIG. 4 is a cross-sectional view of the drive pulley 12.

FIG. 5 is a block diagram of a drive control circuit for driving and controlling the motors 35 and 45.

FIG. 6 is a plan view showing a reproduction start state of the disc 50.

FIG. 7 is a plan view showing a state where the optical pickup 2 is reproducing the outermost peripheral position in the recording range of the disc 50.

FIG. 8 is a plan view showing a reproduction start state of the disc 80.

9 is a bottom view of the disc reproducing device shown in FIG. 8. FIG.

[Explanation of symbols]

 1 Chassis 2 Optical Pickup 3 Objective Lens 4 Turntable 7 Potentiometer 11 Drive Belt 12 Drive Pully 13 Driven Pulley 21 Drive Belt 22 Drive Pully 23 Driven Pulley 31 Slide Plate 32 times Moving arm 35 Motor 41 Sliding plate 42 Rotating arm 45 Motor 46 Drive source 50 12 cm disk 60 Microcomputer 69 Polarity reversing circuit 73 Low-pass filter 80 8 cm disk

Claims (6)

[Claims] 1. A pair of drive belts respectively wound around different edges of a disc over a required angle, a drive source for driving the pair of drive belts, and a reproducing means for reproducing information recorded on the disc. A disc reproducing apparatus comprising: 2. The reproducing means is fixedly arranged without moving in the radial direction of the disk.
The disk reproducing device described in. 3. A pair of drive belts for controlling the drive source to rotate the disc at a required number of revolutions and to move the disc in the radial direction with respect to the reproducing means. 3. The disc reproducing apparatus according to claim 2, further comprising a control unit that changes the speed of the disc. 4. The disc reproducing apparatus according to claim 2, further comprising a turntable on which the disc is mounted and which is movable with respect to the chassis. 5. The pair of drive belts are respectively stretched between a drive pulley and a driven pulley, and stretching directions thereof are substantially parallel to each other. Disc player. 6. The disc reproducing apparatus according to claim 1, wherein the pair of drive belts are movable in directions approaching or separating from each other.