JPH04170755A - Optical disk drive device - Google Patents

Abstract

PURPOSE:To enable rotation to be started at high speed even in the case of an optical disk with different weight by detecting inertial moment of the optical disk and switching the speed for starting rotation of the optical disk in response to a value of the inertial moment. CONSTITUTION:A frequency generator 3 which generates a signal with a frequency corresponding to a speed is provided at a spindle motor 2 which performs rotary drive of an optical disk 1 and the output is converted to a DC voltage which changes in proportion to a frequency by a F/V converter 4. On the other hand, a reference voltage generator 5 generates a reference voltage corresponding to a target speed according to directions of a microcomputer 10. Then, an output of the generator 5 and a DC voltage from the converter 4 are subjected to differential amplification by a differential amplifier 6 and this differential voltage is supplied to a motor drive 8 through a compensation circuit 7, thus enabling a motor 2 to be driven, thus enabling a feedback loop to be formed as a whole and the motor 2 to be driven at a constant speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an information recording and reproducing apparatus for recording and reproducing information on an optical disc.

[Prior Art] In recent years, so-called optical disk drive devices that perform recording and reproduction on optical disks have been put into practical use, and are known from, for example, Japanese Patent Laid-Open No. 2-54470.

This optical disk drive device records and reproduces signals by focusing a laser beam onto a minute area on an optical disk, and is capable of high-density recording.

Further, in this field, the performance of optical discs is being standardized, and efforts are being made to enable multiple types of optical discs based on this standard to be used in the same drive device.

As described above, the optical disc drive device performs recording and reproduction while rotating the optical disc. Therefore, in order to make the optical disc a replaceable medium, the disc rotation is started each time the user inserts the disc cartridge. In order for users to be able to use optical discs as quickly as possible,
It is necessary to design the optical disk so that it can start rotating quickly without slipping and achieve steady rotation.

[Problems to be Solved by the Invention] As described above, it is desirable that the optical disc drive be able to use a plurality of types of optical discs that comply with the standard. However, for example, in the standard for 130mm optical disc,
There is only a regulation that the weight of a disc is 120 g or less, and optical discs made of plastic and optical discs made of glass are currently on the market.

Also, when starting up a spindle motor, a large torque is applied to start up the spindle motor to rapidly start up the rotation. teeth,
Slip occurs between the clamping portion and the disk, and after the disk is raised many times, the clamping area of the disk becomes worn.

SUMMARY OF THE INVENTION An object of the present invention is to provide a drive device that can start rotating optical discs of different weights at high speed without slipping.

[Means for Solving the Problems] The present invention provides an optical disc drive device used for reproducing or recording/reproducing an optical disc.
The present invention is characterized by comprising means for detecting the moment of inertia of the optical disk, and means for switching the rotation start-up speed of the optical disk according to the value of the detected moment of inertia.

[Operation] The magnitude of the moment of inertia differs depending on the type of disc due to the difference in the weight of the disc.

According to the present invention, in order to detect this moment of inertia, preliminary rotation is performed at a sufficiently low target rotation speed with respect to the final target rotation speed of the optical disk, and the time required to reach that rotation speed is performed. measure. Since the pre-rotation speed is sufficiently low, the starting torque is also small, and even heavy discs will not slip.

Optical discs that take a long time to reach the target rotation speed during preliminary rotation have a large moment of inertia, so the final rotation speed is gradually increased to the target rotation speed. Furthermore, since the moment of inertia of an optical disk that has completed its preliminary rotation immediately is small, it can be started up quickly thereafter.

[Embodiment] FIG. 1 shows an example of a rotation speed control system using a normal analog servo. A spindle motor 2 that rotationally drives the optical disc 1 is provided with a frequency generator 3 that generates a signal with a frequency corresponding to the number of rotations of the spindle motor 2, and the output thereof is converted into a DC voltage that changes in proportion to the frequency by an F/V converter 4. Convert to On the other hand, the microcomputer 10 generates a reference voltage according to the target rotational speed according to its instructions. The output of the reference voltage generator 5 is supplied to the inverting input terminal of the error amplifier 6, and the DC voltage from the F/V converter 4 is supplied to the non-inverting input terminal of the error amplifier 6. Therefore, the difference between the output of the reference voltage generator 5 and the DC voltage from the F/V converter 4 is obtained by the error amplifier 6, and this difference voltage is transferred to the compensation circuit 7.
The signal is supplied to the motor drive 8 via the motor 8, thereby driving the spindle motor 2.

In this way, in the present invention, since a feedback loop is formed as a whole, the spindle motor can be driven at a constant rotation speed.

The output of the error amplifier 6 is also supplied to the servo lock detector 9, and it is detected that the value has become 0, thereby detecting that the spindle motor has reached the target rotation speed, and the microcomputer Let me know.

In this system, as shown in Fig. 2, the microcomputer starts the rotation of the optical disk upon completion of the disk chuck, but at this time, it first sets the target rotation speed to a sufficiently low rotation speed of 81 (e.g. 300 RPM) and starts the reference voltage generator. 5 to specify a predetermined voltage value. At the same time, the microcombiner 10 starts measuring the elapsed time and measures the time until the output of the servo lock detector 9 is generated. For light optical discs such as plastic optical discs, it takes a short time to reach a sufficiently low rotational speed 81 (τ1 in the case of curve A in Figure 2), and for heavy optical discs made of glass, it takes a sufficiently low rotational speed S. , becomes longer (τ2 in the case of curve B in FIG. 2).

The microcomputer 10 selects the subsequent method of raising the target rotational speed in accordance with the time as shown below.

That is, the microcomputer 10 sets the designated rotational speed as follows when the disc is light and when the disc is heavy.

Regardless of whether the disk is light or heavy, the microcomputer 10 provides a signal to the reference voltage generator 5 so that a constant potential is applied to the motor when the motor starts rotating. Figure 3 shows that when the disk is light,
FIG. 4 shows the relationship between time and designated rotational speed when the disk is heavy.

As is clear from Figures 3 and 4, even if a constant potential is applied to the motor, it takes time to reach the predetermined step rotation speed (instructed rotation speed) depending on whether the disc is light or heavy. Therefore, if the disk is light, the predetermined step rotation speed will be reached earlier, and if the disk is heavy, the predetermined step rotation speed will be reached later. Therefore, the time required to reach the predetermined step rotation speed (if the disc is light: τ1,
When the disk is heavy: τ2) is measured, and the potential applied to drive the motor thereafter is controlled based on the measured time. That is, if the disk is light (if the time to reach the low target rotational speed 81 is short), the target rotational speed is immediately given as the commanded rotational speed, as shown in FIG. Furthermore, if the disk is heavy (if it takes a long time to reach the low target rotation speed 81), as shown in FIG. ) are sequentially given as the command rotation speed, and the final target rotation speed is 32 (for example, 1
800RPM).

[Second Embodiment] In the above embodiment, the torque was reduced by gradually increasing the designated rotation speed, but other means for slowing the rise of the rush current will be described below.

A second embodiment of the optical disk drive apparatus of the present invention will be described with reference to FIGS. 5 to 7. In this embodiment, a current limiting resistor 13 is inserted in series with the coil winding 11 of the motor 2 at the timing of starting. A relay 12 is connected in parallel to this current limiting resistor 13, and the other end of the current limiting resistor 13 is connected to a power source. motor 2
The other end of the coil winding 11 is connected to the collector of the drive transistor 14, and its emitter is grounded. The base of the drive transistor 14 is connected to the error amplifier 6 via the motor driver 8.

A non-inverting input terminal of the error amplifier 6 is connected to a microcomputer 10 via a reference voltage generator 5. Further, the inverting input terminal of the error amplifier 6 is connected to the F/V converter 4. The rest of the configuration is the same as that described with reference to FIG. 1, so detailed explanation thereof will be omitted. In this example, as shown in FIG. 6, when the disk is light and the period τ1 is shorter than a certain time, the relay 12 is constantly in the ON state and short-circuits the current limiting resistor 13, so that the target rotation speed is 82, the drive current is made to flow through the motor 2. Therefore, even if the motor speed is rapidly increased to the target speed, the disk will not slip.

In addition, when the disk is heavy and the period τ2 is longer than a certain time, the relay 12 is turned off at the end of the period τ2 and the current limiting resistor 13 is connected to the coil winding of the motor, as shown in FIG. 11 in series, the drive current flows to the motor via the current limiting resistor 13, and therefore the rotational speed of the motor gradually increases.

Further, after a period τ3 (time required to reach the step designated rotation speed), the relay 12 is turned on again, and the rush current rises again, and this is repeated several times to obtain the target rotation speed.

In this way, by gradually increasing the rotation speed, the target rotation speed can be reached without slinging the heavy disk.

Next, a third embodiment of the optical disc drive device of the present invention will be described. In this embodiment, the start signal of motor 2 is set to PW.
The motor is started by using M (pulse width modulation).

As shown in FIG. 8, a start signal for the motor 2 is supplied to the motor driver 8, and the motor driver 8
Connect to the winding of The motor start signal makes the motor driver 8 active and drives the motor 2 when the potential is low, and makes the motor driver 8 inactive and stops driving the motor 2 when the motor start signal is high potential.

If the disk is light and the period τ2 is shorter than a certain time, the start signal is at a low potential as shown in the middle row of FIG. The number of rotations should be increased to the target rotation speed.

However, if the disk is heavy and the period τ2 is longer than a certain time, the start signal is pulse width modulated and repeats a low potential and a high potential, as shown in the middle part of FIG. By repeating the driving and non-driving states, the current flowing through the motor is adjusted by increasing or decreasing the duty of driving the motor, and the indicated rotation speed is gradually increased as shown in the lower part of Figure 10. Try to increase the rotation speed to the target speed.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide an optical disc drive device that can reliably start up the rotation of different types of optical discs without slipping.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a first embodiment of the optical disc drive device of the present invention, FIG. 2 is an explanatory diagram showing the relationship between the number of rotations of an optical disc of the optical disc drive device of the present invention and time, and FIGS. 4
FIG. 5 is a block diagram showing the configuration of the second embodiment of the optical disc drive device of the present invention; FIGS. 6 and 7 are the optical disc drive device shown in FIG. 5. FIG. 8 is a block diagram showing the main part of the configuration of the third embodiment of the optical disc drive device of the present invention, and FIGS. FIG. 3 is an explanatory diagram showing a means for giving an instruction rotation speed by a drive device. 1 ... Disk 2 ... Spindle motor 3 ... Frequency generator 4 ... F/V converter 5 ... Reference voltage generator 6 ... Error amplifier 7 ... Compensation circuit 8 ...・Motor drive 9...-Servo vine detector 10...Microcomputer 11...
Motor winding 12 ... Relay 13 ... Current limiting resistor 14 ... Drive transistor 1 ... Disk 2 ... Spindle motor 3 ... Frequency generator 4 ... F/V converter 5 ... Reference voltage generator 6 ... Error amplifier 7 ... Compensation circuit 8 ... Motor drive 9 ... Servo port/link detector 10 ... Microcomputer No. 1b Fig. 2 O-shi1 2 hours Figure 5 Figure 7 Figure 8 Star toy color number

Claims (2)

[Claims] (1) An optical disc drive device used for reproducing, recording and reproducing an optical disc, including means for detecting the moment of inertia of the optical disc, and means for switching the rotation start-up speed of the optical disc according to the value of the detected moment of inertia. An optical disc drive device featuring: (2) The optical disk drive device according to claim 1, wherein the moment of inertia detection means measures the time required to reach a target rotational speed lower than a target rotational speed.