JPH0753167Y2 - Disc player tray drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Use The present invention is slidably supported between a loading / unloading position where a disc is loaded and unloaded and a storage position where a disc is loaded on a turntable. The present invention relates to a tray drive device of a disc player provided with a tray, and more particularly to a tray drive device suitable for a disc player provided with a disc clamp device that press-holds a disc on a turntable by utilizing magnetic force from a magnet.

(B) Conventional Technology An optical disc player is known in which a signal recorded on a disc is optically reproduced by using an optical pickup. In most optical disc players, the tray is slidably supported between a loading / unloading position where the disc is loaded and unloaded and a storage position where the disc is loaded on the turntable, and the tray is displaced to the loading / unloading position. When the disc is mounted on the tray and the tray is closed, the tray is automatically slid to the storage position and the disc is mounted on the turntable. Also,
Since the optical disc player needs to rotate the disc at a high speed, it is equipped with a disc clamp device for crimping and holding the disc on the turntable. In the disc clamp device, for example, as disclosed in Japanese Patent Laid-Open No. 60-80159, a clamp plate having a chucking member for pressing a disc in the direction of the turntable at a position opposed to the turntable is usually provided at a clamp position and an unclamped position. Is supported so that it can be displaced between the position and the disk, and when the tray driving motor displaces the tray to the storage position, the clamp plate is displaced to the clamp position in conjunction with the sliding operation of the tray. Is configured to be crimped onto the turntable.

By the way, as a disc clamp device, for example, as disclosed in Japanese Utility Model Laid-Open No. 61-21042, the turntable is made of a magnetic material, and a magnet is attached to a surface of the chucking member facing the turntable. It is known that the disc is pressed onto the turntable by the suction force generated by the disc. By doing so, the disc is securely pressed onto the turntable.

(C) Problems to be Solved by the Invention However, the disk clamp device using the magnet has a problem in that the disk is clamped, that is, the disk is interposed between the turntable and the chucking member. Since the magnetic force generated from the magnet is set so that the turntable is securely pressed onto the turntable, when the disc is not mounted on the turntable, the turntable and the chucking member become stronger. Is crimped to. Therefore, in this case, even if the sliding operation of displacing the tray from the storage position to the attachment / detachment position is performed and the operation of displacing the clamp plate to the non-clamping position is performed, the chucking member is easily removed from the turntable. If the drive force of the motor is increased in order to perform the operation smoothly, the tray will be displaced to the attachment / detachment position and the mechanism will be suddenly stopped. There is a new drawback that the phenomenon of swinging the tray occurs.

(D) Means for Solving the Problems The present invention has been made in view of the above-mentioned points, and generates a signal from the operation of opening the tray to the time when the tray is displaced to the attachment / detachment position and the operation of opening the tray. Signal generating circuit for generating a signal having a voltage level higher than the signal subsequently generated in a predetermined time from, and a motor drive for driving the motor for driving the tray and the clamp plate according to the signal from the signal generating circuit. And a circuit.

(E) Action The present invention ensures that the clamp plate is at the unclamped position at the start of sliding from the storage position of the tray by increasing the drive voltage generated from the motor drive circuit for a predetermined time after the tray opening operation. In addition, the tray is slid slowly when the tray reaches the attachment / detachment position.

(F) Embodiment FIG. 1 shows an embodiment of the present invention. (1) is a motor for driving a tray and a clamp plate (not shown),
(2) is an operational amplifier that generates a drive voltage for driving the motor (1), (3) is an open / close switch (4) for opening and closing the tray, and is closed when the tray is displaced to the attachment / detachment position. A first switch (5) that is closed and a second switch (6) that is closed when the tray is displaced to the storage position, and outputs an output signal according to the detected state. A microcomputer having two terminals (7) and (8), and (9) and (10) for connecting a power supply to the first terminal (7) and a power supply to the second terminal (8), respectively. A second resistor, (11) is a diode whose anode is connected to the first terminal (7),
(12) is a third resistor connected between the cathode of the diode (11) and the non-inverting input terminal of the operational amplifier (2),
(13) is a first capacitor connected in parallel with the third resistor (12), (14) is a fourth resistor connected between the non-inverting input terminal of the operational amplifier (2) and the ground, (15) ) Is a fifth resistor connected between the second terminal (8) and the inverting input terminal of the operational amplifier (2), and (16) is an output terminal of the operational amplifier (2) and the inverting input terminal of the operational amplifier (2). A sixth resistor (17) is connected to the input terminal and sets the negative feedback amount of the operational amplifier (2) in consideration of the resistance value of the fifth resistor (15). The second capacitor is connected in parallel to 16) and smoothes the output voltage from the operational amplifier (2).

By the way, the microcomputer (3) detects the direction in which the tray is slid from the switching state of the open / close switch (4), the first switch (5) and the second switch (6), and according to the detection output, the first terminal (7) or an output signal is generated from the second terminal (8).
The terminal (7) is set to the “H” level only when the tray is closed from the attachment / detachment position to the storage position and is set to the “L” level otherwise, and the second terminal (8) is attached / detached from the storage position. It goes to "H" level only when the tray is opened toward the position, and goes to "L" level at other times.

In the circuit of FIG. 1, a predetermined time (number + ms) according to the discharge time constant of the first capacitor (13) determined by the capacity of the first capacitor (13) and the resistance value of the fourth resistor (14).
As described above, when the first terminal (7) of the microcomputer (3) is set to the "L" level, the first capacitor (13)
, The first capacitor (13) is in a discharged state when the tray is displaced to the storage position.

Now, when the open / close switch (4) is operated to mount the disc on the tray while the tray is displaced to the storage position, the first terminal (7) of the microcomputer (3) becomes "H" level. . At this time, since the first capacitor (13) is in the discharged state, the non-inverting input terminal of the operational amplifier (2) is connected to the diode (+ B) from the power supply voltage (+ B) when the open / close switch (4) is operated. 1
A voltage obtained by dividing the voltage obtained by subtracting the conduction voltage of 1) by the resistance value of the first resistor (9) and the resistance value of the fourth resistor (14) is applied, and then the first capacitor (13) is charged. Accordingly, the voltage applied to the non-inverting input terminal of the operational amplifier (2) gradually decreases. Then, the first capacitor (1
When 3) is fully charged, the non-inverting input terminal of the operational amplifier (2) is connected to the diode (1) from the power supply voltage (+ B).
A voltage obtained by dividing the voltage obtained by subtracting the conduction voltage of 1) by the combined resistance value of the first and third resistors (9) and (12) and the resistance value of the fourth resistor (14) is applied. . Here, since the second terminal (8) of the microcomputer (3) is held at the “L” level, the operational amplifier (2) generates an output voltage according to the voltage input to the non-inverting input terminal. It Therefore, the motor (1) is the same as the operational amplifier (2).
The tray is driven according to the voltage input to the non-inverting input terminal of the tray, and the tray is displaced to the attachment / detachment position.

By the way, the charging time constant of the first capacitor (13) is determined according to the time during which the operation of displacing the clamp plate from the clamp position to the non-clamp position is performed, and the capacitance of the first capacitor (13) and the first resistance (13) It is set by the resistance value of (9). Therefore, during the period in which the clamp plate is displaced to the non-clamp position in conjunction with the sliding movement of the tray, the drive voltage applied to the motor (1) during the steady state of the sliding displacement of the tray other than that period is Since a high driving voltage is applied to the motor (1), the disc (1) is not mounted on the turntable in the disc player configured to press the disc onto the turntable using magnetic force. ), Even if the load is significantly increased, the motor (1) continues to rotate smoothly,
The sliding operation of the tray is performed smoothly.

When the tray is slid to the attachment / detachment position by continuing the rotation of the motor (1), the displacement of the tray causes the first switch (5).
Are closed, and the first terminal (7) of the microcomputer (3) becomes "L" level. Here, the first capacitor (13) is connected to the first terminal (7) by the diode (11).
Since it is separated from, it is quickly discharged through the fourth resistor (14). Therefore, the non-inverting input terminal of the operational amplifier (2) does not significantly swing in the negative polarity due to the charge stored in the first capacitor (13), and the operational amplifier (2) does not generate a negative output voltage. Therefore, the motor (1) is quickly stopped when the first terminal (7) becomes the “L” level, and the sliding of the tray is stopped.

2 (a), (b) and (c) are characteristic diagrams showing the above-mentioned operation. 2 (a) shows the output level of the first terminal (7) of the microcomputer (3), and FIG. 2 (b) shows the output voltage from the operational amplifier (2).
The figure (c) shows the motor current flowing through the motor (1). The horizontal axes of FIGS. 2 (a), (b) and (c) represent time, and t ₀ is the time when the open / close switch (4) is operated, t ₁
Is the time at which the clamp plate is displaced from the clamp position to the non-clamp position, and t ₂ is the first switch (5).
Shows when each is closed.

On the other hand, when the tray is displaced to the attachment / detachment position,
When the disc is mounted on the tray and the open / close switch (4) is operated, the second terminal (8) of the microcomputer (3)
Becomes "H" level. Therefore, at the inverting input terminal of the operational amplifier (2), the power supply voltage (+ B) is divided by the combined resistance value of the second and fifth resistors (10) and (15) and the resistance value of the sixth resistor (16). The compressed voltage is applied. Since the first terminal (7) of the microcomputer (3) is held at the “L” level, the operational amplifier (2) has a polarity opposite to that when the tray is displaced to the attachment / detachment position. An output voltage corresponding to the voltage input to the inverting input terminal is generated. Therefore, the motor (1) is driven at a constant voltage according to the voltage input to the inverting input terminal of the operational amplifier (2), and the tray is displaced to the storage position.

(G) Effect of the Invention As described above, according to the present invention, in the period in which the displacement of the clamp plate to the non-clamping position is interlocked with the sliding movement of the tray, the steady state of the sliding displacement of the tray other than the period is performed. Since a drive voltage higher than the drive voltage sometimes generated by the motor drive circuit is generated by the motor drive circuit, the drive force for displacing the clamp plate to the non-clamp position can be increased, and the magnetic force is used to drive the disc. Even if the disc is not mounted on the turntable, the clamp plate can be smoothly displaced from the clamp position to the non-clamp position in a disc player configured to crimp the disc onto the turntable, and the sliding displacement of the tray is steady. Since it is not necessary to increase the drive voltage generated from the motor drive circuit during the state, the tray when the tray reaches the loading / unloading position (A) It has an advantage that it is possible to prevent the head swing phenomenon from occurring.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIGS. 2 (a), (b) and (c) are characteristic diagrams showing characteristics of main parts of the circuit diagram of FIG. Description of main drawing numbers (1): motor, (2) ... operational amplifier, (3) ... microcomputer, (11) ... diode, (13) ... first capacitor.

Claims (1)

[Scope of utility model registration request] 1. A tray slidably supported between an attachment / detachment position at which a disc is attached / detached and a storage position at which a disc is mounted on a turntable, and the disc is placed on the turntable by magnetic force. A chucking member for crimping is provided, and a clamp plate supported so as to be displaceable between a clamp position and a non-clamp position for crimping the disc onto the turntable is provided, and the clamp plate is slidable on the tray. In a disc player having a structure in which the tray is displaced in association with the tray and is displaced to a non-clamp position when the tray is displaced from the storage position to the attachment / detachment position, a motor for driving the tray and a drive voltage for driving the motor. Generating a motor drive circuit and a control signal for controlling the motor drive circuit, and the displacement of the clamp plate to the non-clamp position causes the tray to move. Generates a control signal that causes the motor drive circuit to generate a drive voltage higher than the drive voltage generated by the motor drive circuit during the steady state of the sliding displacement of the tray other than that period during the period that is performed in conjunction with the sliding operation. And a signal generating circuit for driving the tray. A tray driving device for a disc player, wherein the driving force for displacing the clamp plate to the non-clamping position is increased against the magnetic force of the chucking member attracted to the turntable. .