JPS6057542A - Focus controller of disc device - Google Patents

Abstract

PURPOSE:To control always the interval between a disc and an objective lens of a detector most suitably by driving a driving part, which operates a bearing part, so that the DC offset quantity of a focus error signal, which is obtained when the objective lens of the detector is operated in the focus direction, is within a prescribed voltage range or zero volt. CONSTITUTION:A focus error signal 33 obtained through an actuator 31 which controls an objective lens 32 of a detector 30 in the focus direction is inputted to a detecting circuit 34, and one output of the circuit 34 passes through a focus servo circuit 35 to drive the actuator 31, and the other is inputted as a DC voltage 36 of the focus error signal to a comparing circuit 39 and is compared. If the DC voltage 36 of the focus error signal is not within a prescribed voltage range 38, a voltage signal 40 which drives a driving motor 25 is outputted from the comparing circuit 39 to drive the driving motor 25, and a spindle 13 is moved vertically to move a turntable 12, namely, a disc 1 vertically (in the focus direction), and thereby, the disc 1 is so moved that the interval between the disc 1 and the reference position of the object lens 32 is allowable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a disc device in which the distance between the objective lens position of a detection device and the disc surface position is determined.

The present invention relates to a focus control device for always maintaining an optimum value.

[Background of the invention]

In conventional disk drives, the positioning accuracy of the detection device with respect to the disk surface is set strictly to ensure performance. In particular, the distance between the objective lens position of the detection device and the disk surface position (dimension in the focus direction) is very strict due to the vertical vibration of the disk and the movable range of the objective lens.
(approximately 200 μm) positioning must be performed.

However, even if the dimensional accuracy of each part is increased in the assembly of a mechanical system, at the time of assembly, it will still be within the set accuracy.
Unable to satisfy the accuracy, at present, dimensions are measured after being assembled several times.

The problem is that the workability is extremely poor, in that the spacer etc. is selected so that it falls within the set value, the assembled device is disassembled, the selected spacer is manually reassembled, and the spacer etc. is set within the predetermined size. there were.

Furthermore, even if the dimensions are set within the specified range, there will be no problem at the inner circumference of the disc, but at the outer circumference of the disc, the disc may deviate from the optimum position due to bending or warping, resulting in deterioration in playback performance, etc. There are problems that arise.

Therefore, there is a need for a Jiff system that can always ensure optimal positional accuracy in the focus direction, regardless of the inner or outer circumference of the disk, and even outside the predetermined dimensions at the time of initial assembly.

[Purpose of the invention]

An object of the present invention is to solve the problems of the prior art described above and to provide a focus control device that always optimally controls the distance between the disk surface of a disk device and the objective lens of a detection device. [Summary of the Invention] In order to always control the distance between the disk surface and the objective lens of the detection device in an optimal state, the present invention provides a disk rotating device that holds the disk and performs high-speed rotation, in which a spindle to which a turntable that holds the disk is fixed is moved in the axial direction. The bearing part that holds the spindle in the axial direction is also movable in the axial direction, and by providing a drive part that moves the bearing part in the axial direction, the objective lens of the detection device is moved in the focus direction. By driving the drive section that operates the bearing section so that the DC offset amount of the focus error signal when the spindle is operated is within a predetermined voltage or becomes zero volts, the spindle is moved in the axial direction - that is, the disk is moved in the axial direction. The present invention is characterized in that the distance between the disk and the objective lens of the detection device is always optimally controlled by moving the disk to the objective lens of the detection device.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a system block diagram of a focus control device for a disk device showing an embodiment of the present invention, FIG. 2 is an operational waveform diagram of the main parts in FIG. 1, and FIG. The detailed configuration diagram of the rotating device, FIG. 4, shows the disk device u.
FIG. 2 is an explanatory diagram of the operation at startup.

In the figure, 1 is a disk, 2 is a disk rotation device 10
, and a shahn holding the detection device 30 etc., 11ba,
A holding part 16 that holds the disc 1 mounted on the turntable 12 fixes the turntable 12 and is connected to the arrow C.
14 is a holder that is equipped with a bearing 15 and holds the spindle 12; 16 is a stator unit 17 to which a drive coil is fixed;
A rotor unit 18 to which a magnet is fixed for rotation 2 is a base holder fixed to a pace plate 20 fixed by a shaft 21, and 19 is a base holder 1.
8 is engaged with a screw to hold the spindle 1'5 in the direction of arrow C; 25 is a drive motor holding a gear 26; A movable guide section 61 is an actuator that moves the objective lens 62 in the focus direction (perpendicular to the disk 1 - axial direction of the spindle 13) in the detection device 30; Focus error signal, 34 is a detection circuit, 6
5 is a focus servo circuit, 6 is a DC voltage of a focus error signal, and 37 is a comparison circuit 69.

Predetermined voltage 38 to be compared with the DC voltage of the focus error signal
40 is a voltage signal for driving the drive motor 25, and 50 is an accurate displacement amount with respect to the distance between the disk 1 and the objective lens 62.

Next, the operation will be explained.

The disk 1 is mounted on a turntable 12 of a disk rotating device 10, and is rotated at high speed by the disk rotating device 10 while being held by a holder 11. Then, the objective lens 32 of the one detection device 30 is servoed in the focusing direction with respect to the rotating disk 1 by the actuator 61, and furthermore, the well-known tracking servo (
(not shown) etc., information signals are recorded and reproduced on the disc 1. In addition, guide part 2
Since the detection device 30 is held by 9 and is movable in the radial direction of the disk 10, it is possible to access any arbitrary position of the disk 1 by a drive mechanism system (not shown) that operates the detection device 30. .

By the way, is the objective lens 32 of the detection device f30 in the focus direction? The actuator 51 to be controlled by Ii is generally composed of an electromagnetic device row, and in order to ensure a predetermined sensitivity, the operating range of Considering Bray etc.1
If, in order to perform good focus control over the entire recording area of the disc 1, the distance f between the reference position of the objective lens 32 and the surface of the disc 1, that is, the chassis of the turntable 12 that holds the disc 1, must be It was necessary to ensure positional accuracy when installing 2.

However, in the present invention, the focus error signal 33 obtained through the actuator 51 that controls the focus direction VC to detect whether the objective lens of the detection device 30 is defective is inputted to the detection circuit 64, and one of the outputs is inputted to the detection circuit 64 via the focus servo circuit 35. The actuator 61 is driven, and the DC voltage 56 of the focus error signal is inputted to the comparison circuit 39vc, and the comparison circuit 69 compares it with the predetermined voltage 38 inputted from the reference voltage generation circuit 7 to obtain the DC voltage of the focus error signal. ′! I6 is within the predetermined voltage 38 [If not, the comparator circuit 39 outputs a voltage signal 40 for driving the drive motor 25 to drive the drive motor 25, and the spindle 13
By moving the turntable 12, that is, the disk 1 up and down (in the focus direction), the disk 1 is moved to an allowable distance with respect to the reference position of the objective lens 52.

This will be explained in more detail using FIG.

That is, when the turntable 12 is mounted higher than a predetermined dimension with respect to the steering wheel 2 in assembling the disk rotating device 60, the distance between the disk 1 and the objective lens 32 becomes larger than the predetermined dimension. Therefore, when focus control is performed on the objective lens 32 of the detection device 30, the DC voltage 36 of the focus error signal generates a DC voltage with a slight offset i (+a') from the reference position (zero volts). , disk 1 and objective lens 6
Corresponding to the tolerance value (±b) of the interval accuracy (ΔL) with respect to 2,
Allowable voltage (±a) output from the reference voltage generation circuit 37
When compared with the offset amount (±a) for the allowable voltage (±a)
+a') is large, a voltage of 4° for driving the drive motor 25 is applied from the comparison circuit 38 to the drive motor 25 so that the offset amount is within the allowable voltage range, and the voltage 4° for driving the drive motor 25 is applied to the drive motor 25.
By driving the spindle 13. The disk 1 moves in the focus direction via the turntable 12, and when the voltage falls within the allowable range, the driving of the drive motor 25 is stopped.
The distance accuracy between the disk 1 and the objective lens 32 (△J,
) can be set within an allowable value.

In addition, especially when the detection device 30 is detecting the outer periphery of the disk 1, the DC voltage 66 of the focus error signal may exceed the allowable voltage -a due to deflection of the disk 1, etc., as shown in FIG. In this case, the voltage 40 for driving the drive motor 25 is generated from the comparator circuit 69, and the interval accuracy is set within the permissible value.

In FIG. 2, the output voltage 38 of the reference voltage generation circuit 37 is set to the tolerance value (±b) of the interval accuracy [corresponding tolerance voltage (±a), but the output voltage 38 of the reference voltage generation circuit 37 voltage 38 - actuator 31 and objective lens 3
If the distance between the disk 1 and the objective lens 62 is set to the reference position 2, that is, equivalent to the DC voltage of zero volts of the focus error signal, the distance between the disk 1 and the objective lens 62 can always be controlled to a predetermined dimension.

Next, a method of moving the disk 1 by driving the drive motor 25 will be explained using FIG.

As the disk rotating device 10, a spindle 13 to which a turntable 12 is fixed is held by a bearing 15 of a holder 14, and a base holder 1 fixed to a base plate 20 is supported by a bearing 15 of a holder 14.
Axial support is achieved by a bearing portion 19Vc engaged with B by a screw. In addition, the spindle 13iC is fixed with 16 rotor units to which magnets are fixed.
Facing the rotor unit 16 1. A stator unit 17 is provided to which a drive coil is fixedly attached, and a rotor unit 16 rotates due to the relationship between the drive coil and the magnet, that is, a spindle 10. A disk 1 held by a holding section 11 is rotated via a turntable 12.

By the way, the bearing part 19 that is engaged with the base holder 18 by a screw has a gear part 19A that engages with a gear 26 held by a drive motor 25, and when the drive motor 25 is driven, the gear 26 is moved. It rotates in the six directions of arrows, and the bearing part 19 also rotates in the direction of arrow B via the gear part 19A. That is, since the base holder 18 is in a fixed state, the rotation of the bearing part 19 in the direction of arrow B causes the bearing part 19 to move in the axial direction at the same time as the rotational movement, corresponding to the pitch of the threaded part. As the portion 19 moves in the axial direction, the spindle 13 also moves in the direction of arrow C (axial direction), and the disk 1 can be moved in the direction of arrow C (focusing direction).

Next, with reference to FIG. 4, the setting state of the disk 1 position at the time of starting up the disk device will be explained.

That is, in assembling the disk rotating device 10, etc.
When the distance between the disk 1 and the objective lens 32 is smaller than a predetermined dimension, the focus control in the retracting operation of the objective lens 32 is as follows: This requires an operation of lowering the objective lens 32 to perform just focus control, which complicates focus control during the retracting operation of the objective lens 32.

Therefore, by loading the disk 1 into the disk device, the predetermined scene disk 1 is moved upward (generally based on the output from a disk presence/absence detection device using a photo sensor or the like).
In other words, the distance accuracy (Δ
Drive motor 25 until bearing part 1z spindle 15.L) becomes +X amount. The disk 1 is moved via a turntable 12.

Thereafter, by controlling the focus of the objective lens 62, the distance between the disk 1 and the objective lens filter 2 is always higher than the allowable accuracy range for the reference position. By constantly increasing the distance, just focus is achieved by one-way operation, and focus control is then performed based on the DC voltage of the focus error signal described above so that the distance between the disk 1 and the objective lens 62 is within a predetermined dimension.

In this article, we explained how to set disk 1 by using the time when the disk device starts up.However, when the disk device is operating, it is necessary to finish the operation and set disk 1 by using the 5 I+ setting signal. It is also possible to carry out the seven-segment state of This also has the effect of preventing problems such as damage to the disk 1 or objective lens 32 due to contact with the lens 62.

〔Effect of the invention〕

As described above, according to the focus control device Wt of the disk device of the present invention, in assembling the disk rotation device,
Even if the dimensions of the turntable that performs disk positioning are not the specified dimensions, the spindle or turntable must be mounted so that the DC voltage of the focus error signal generated when the objective lens of the detection device is focused is within the specified voltage. Equipped with a drive motor that moves in the vertical direction (focus direction) - By driving this drive motor, it is possible to always set the distance between the disk and the objective lens to a predetermined dimension, so there is no need for disk positioning work. This improves work efficiency and eliminates performance deterioration at the outer periphery of the disk, which occurs especially due to disk warpage and deflection, ensuring optimal performance at all times.

In addition, by performing control to set the disk position higher than a predetermined size when starting and stopping the disk device, the objective lens can be set as the direction of focus control operation when the objective lens is retracted when starting the disk device. This can be referred to as one-way operation control that constantly moves upward to detect just focus, making it easy to control the focus at startup, and when setting the disk position when the disk drive is stopped. In devices where the distance between the disk and the objective lens of the detection part is small (devices with a small optical beam spot diameter), it is possible to prevent damage to the disk and objective lens due to contact between the disk and the objective lens, and the active ability and It is possible to provide a disk device with high reliability and excellent work efficiency.

[Brief explanation of the drawing]

FIG. 1 is a system block diagram of the focus control device of the disk device, FIG. 2 is a main operation waveform diagram of FIG. 1, FIG. 5 is a detailed configuration diagram of the disk rotation device of FIG. 1, and FIG.
The figure is an explanatory diagram of the operation when the disk device 6 is started. 1: Disc, 2: Yasushi, 1o: Disk rotation device, 12: Turntable, 16: Spindle, 19: Bearing section, 25: Drive motor, 6o: Detection device, 32: Objective lens - 36: DC of focus error signal Voltage, 39:
Comparison circuit. 7. To Pa. Representative Patent Attorney Akira Takahashi Latohy" Figure 1 Figure 752 Section 3 "41', lf, 74 Suf' 17 JAq-F, -
OM bathing oW

Claims (1)

[Claims] In a disk device equipped with a disk rotation device that holds a disk and rotates it at high speed, and a detection device that records and reproduces information signals on the disk, the disk rotation device has a turntable that holds the disk fixedly. The spindle is made movable in the axial direction, a bearing part for holding the spindle in the axial direction is also movable in the axial direction, and a drive part is provided for moving the bearing part in the axial direction, and the drive part A disk device characterized in that the control is performed such that the DC offset amount of the focus error signal when the objective lens of the detection device k is moved in the focus direction is within a predetermined voltage or equal to a reference voltage value. Focus control device.