JP2004006014A - Disk driving device and disk player provided with the disk driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk player capable of stable fast reading by suppressing vibrations caused by a driving mechanism inside the player. <P>SOLUTION: This optical disk driving device or this disk player provided with the optical disk driving device includes a turntable having a mounting surface for mounting an optical disk thereon and a first frame for mounting the turntable thereon. A second frame is arranged over the first frame or more desirably over the first frame and under the mounting surface of the turntable. The second frame is attached to the first frame through an elastic member. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk reproducing apparatus provided with a vibration damping mechanism against vibrations, particularly vibrations generated by rotation of a spindle and an optical disk mounted on the spindle.
[0002]
2. Description of the Related Art For example, an optical system and a servo system in an optical disk reproducing apparatus for reproducing an optical disk such as a CD (compact disk) player (including a CD-ROM drive) and a VD (video disk) player are externally added. There is a limit in the ability to perform accurate tracking control and focusing control with respect to vibration and vibration generated by the apparatus itself. In particular, when used as a storage device of a computer, vibrations generated by the device itself have become an important problem for speeding up a driving device such as high-speed reading and high-speed seeking.
For this reason, a structure is generally adopted in which the entire mechanism or the reproducing mechanism (optical system mechanism) is supported by an elastic body, and external vibration is attenuated by the internal resistance of the elastic body. FIG. 9 shows a CD player as an example of a device having a structure for attenuating such external vibration. As shown in the figure, the edge of the main frame 4 is elastically supported on the housing 1 via the elastic member 2. A spindle motor 7 having a turntable 6 for rotating an optical disk is attached to the main frame 4.
A pickup 5 for reading information from the optical disk is provided on the main frame 4 so as to be movably engaged along guide rails 11a and 11b. It is engaged with a drive screw 8 to move in the radial direction of the optical disc mounted thereon and guide it to a predetermined track. The driving screw 8 has one end connected to a stepping motor 9 so that the driving force is transmitted.
The driving screw 8 is rotated by the rotation of the stepping motor 9, and the pickup 5 moves in the radial direction of the optical disk. The moving direction of the pickup 5 is determined by the rotating direction of the stepping motor 9.
The pickup 5 is, for example, an optical pickup comprising a generally used laser light source and an optical system such as a lens, and includes an actuator having a drive coil for driving an objective lens (not shown) for focus control and tracking control. I have.
In the optical disk reproducing apparatus having the above configuration, when the optical disk (not shown) is rotated via the turntable 6 by the rotation of a spindle motor (not shown) provided on the main frame 4, the imbalance of the optical disk or the like is performed. Accordingly, the entire mechanism of the main frame 4 including members (not shown) mounted on the main frame 4 vibrates. Particularly, when a high-speed information reading speed is required, the frequency of vibration increases because the spindle rotation speed increases, and the force generated by the vibration also increases.
[0008] Since the housing 1 is connected to the housing 1 via an elastic member 2 such as rubber, resin, spring, or the like, the vibration of the main frame 4 is attenuated and transmitted to the housing 1. 1 can be reduced. Further, external vibration applied to the housing 1 from outside is also attenuated by the elastic member 2 and transmitted to the main frame 4, so that the amount of vibration transmitted to the main frame 4 is reduced.
FIG. 10 shows a vibration model of an object having a mass (m) via an elastic body having a hardness (stiffness) k and a viscosity coefficient μ as a model having a structure as shown in FIG. As shown in FIG. 10, a main frame 20 having a mass m0 is elastically supported in a casing 1 having a mass m1 by an elastic member 2 which is an elastic body having a hardness k and a viscosity coefficient μ. Has a structure in which the transmission of external vibration to the main frame 20 is attenuated by the elastic resistance of the elastic member 2 and the own weight of the main frame 20 even if the external frame receives vibration. Here, if the external force is F and the displacement of the main frame is x, it is known that there is a relationship of md2x / dt2 = F-μdx / dt-kx. By solving this equation of motion under certain conditions, the relationship between the resonance frequency f0 and the mass m can be obtained, and the resonance frequency f0 is f0 = 1 / (2π) * (k / m) 1/2 It can be expressed by the following relational expression. Here, when the ratio of the resonance frequency f1 of the mass 1 with respect to the housing 1 and the resonance frequency f0 of the mass m0 with respect to the main frame 20 is obtained, f0 / f1 = (m1 / m0) 1/2, and the mass m0 is doubled. Then, the resonance frequency f1 becomes about 0.7 times. As described above, in the vibration system represented by the mass separated from the vibration source by the elastic member, the transfer characteristic is represented by the mass, the hardness and the damping coefficient of the elastic member, and the mass, hardness, and the damping coefficient are selected. Desired characteristics can be obtained.
From the above results, in order to block the vibration between the outside of the housing 1 and the main frame 20, the hardness of the elastic member 2 is reduced and the mass of the main frame 20 connected by the elastic member is increased. Is effective. However, in order to combine them as a product, the size of the structure is limited as small as possible, and it is difficult to increase the mass of the main frame 20. Therefore, it is necessary to set the hardness of the elastic member 2 low. Has been done.
[0011]
The above-mentioned optical disk reproducing apparatus has a structure in which external vibration is attenuated by elastically supporting the space between the housing 1 and the main frame 4.
At this time, the main frame 4 including the pickup 5 and the turntable 6 mounted via the guide rails 11a and 11b has a structure that is hardly affected by external vibrations due to the action of the elastic member 2. However, the elastic coefficient of the elastic member 2 against the vibration of the main frame 4 itself due to the imbalance or the like due to the high speed rotation of the optical disk due to the eccentric amount of the optical disk (not shown) mounted on the turntable 6 Is kept low, the main frame 4 itself tends to vibrate.
As described above, when the pickup 5 mounted on the main frame 4 via the guide rails 11a and 11b vibrates with respect to the optical disk, a large load is imposed on the servo operation for controlling the reading of information and normal operation is performed. In some cases, information cannot be read.
The present invention has been made in view of such circumstances, and in order to suppress vibration caused by a drive mechanism inside the apparatus, a sub frame is connected to a main frame including a drive mechanism via an elastic body. It is an object of the present invention to provide an optical disk drive capable of performing stable and high-speed reading and a disk reproducing apparatus including the drive.
[0015]
According to a first aspect of the present invention, there is provided a disk driving apparatus for driving an optical disk, comprising: a turntable having a mounting surface on which an optical disk is mounted; A first frame on which a table is mounted; and a second frame provided between the mounting surface of the turntable and the first frame. The second frame is attached to the first frame via an elastic member.
According to a second aspect of the present invention, there is provided the disk drive device according to the first aspect, wherein the turntable is provided with a spindle motor for driving the optical disk to rotate. The center of gravity of the sub-frame block including the second frame is located on the rotation axis of the spindle motor.
Preferably, the sub-frame block has a flat plate shape.
According to a third aspect of the present invention, there is provided a disk drive according to the first or second aspect, and a housing for supporting the first frame of the disk drive via an elastic member. And a disk reproducing device comprising: Further, it is preferable that the second frame contains at least a metal.
Further, it is preferable that the weight of the sub-frame block composed of the second frame is 1/10 to 1/3 of the weight composed of the first frame.
Preferably, the elastic body is made of rubber or resin.
[0021]
In the optical disk drive and the disk reproducing apparatus according to the present invention, the second frame is disposed between the mounting surface of the turntable and the first frame, and the second frame is interposed by the elastic member. Thus, the vibration of the main frame, which is the first frame on which the spindle motor for driving the optical disc is mounted, can be suppressed while effectively securing the space efficiency.
Further, by setting the center of gravity of the sub-frame block including the sub-frame as the second frame on the rotation axis of the spindle motor, it is possible to effectively suppress the vibration caused by the imbalance of the optical disk. .
If the shape of the sub-frame block is flat, the thickness of the optical disk reproducing apparatus can be reduced, and the vibration caused by the optical disk imbalance can be effectively suppressed.
If the sub-frame is made of metal, the sub-frame itself can be made smaller, so that the entire chassis can be made smaller.
If the weight of the sub-frame block is set at 1/10 to 1/3 of the weight of the main frame, the vibration of the optical disk during high-speed rotation can be effectively suppressed.
If the elastic body is made of rubber or resin, an inexpensive and effective vibration suppressing effect can be achieved.
[0027]
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing an optical disk reproducing apparatus according to the present invention, and FIG. 2 is a sectional view thereof.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In FIGS. 1 and 2 described below, the same components as those in FIG. 9 are denoted by the same reference numerals, and redundant description will be omitted.
In FIG. 1, an edge around the main frame 4 is elastically supported on the housing 1 via an elastic member 2 as a first elastic member. Further, a sub-frame 32 is mounted on the main frame 4 via a second elastic member 31 as a second elastic member.
A spindle motor 7 having a turntable 6 for rotating the optical disk 10 (FIG. 2) is mounted on the main frame 4.
The main frame 4 is provided with guide rails 11a and 11b parallel to each other, and the pickup 5 is provided movably engaged along the guide rails 11a and 11b and reads an optical disk. Tracks are arranged to be selectable in the radial direction of the optical disk. The pickup 5 is engaged with a driving screw 8 for moving the pickup 5 in the radial direction of the optical disk to guide a predetermined track. The drive screw 8 has one end connected to a stepping motor 9.
The driving screw 8 is rotated by the rotation of the stepping motor 9, and the pickup 5 moves in the radial direction of the optical disk. The moving direction of the pickup 5 is determined by the rotating direction of the stepping motor 9.
A sub-frame 32 is mounted on the main frame 4 via a second elastic member 31.
In the optical disk reproducing apparatus having such a configuration, when external vibration is applied to the housing 1, the main frame 4 is elastically supported by the housing 1 via the elastic member 2. The vibration of the main frame 4 side is prevented by the action of the member 2.
Here, when the optical disk is rotated, the main frame 4 is vibrated by the imbalance of the optical disk 10 rotated by the spindle motor 7, and is provided via the main frame 4 and the second elastic member 31. It is transmitted to the subframe 32. Therefore, the vibration occurs according to the transmission characteristics of the sub-frame 32 and the second elastic member 31.
At a frequency sufficiently lower than the resonance frequencies of the two vibration systems, the sub-frame 32 moves integrally with the main frame, and at a frequency sufficiently higher than the resonance frequency, the sub-frame 32 hardly transmits vibration from the main frame.
In the vicinity of the resonance frequency, when the braking is small, the vibration is emphasized, and when the braking is large, the influence of the secondary resonance does not appear. The phase of the transmitted vibration is the same at a frequency lower than the resonance frequency, the opposite phase at a frequency higher than the resonance frequency, and the phase at 90 degrees at the resonance frequency. Therefore, by appropriately selecting the resonance frequency and the damping coefficient, the sub-frame 32 has a vibration suppression effect for a vibration frequency substantially equal to or lower than the vicinity of the resonance frequency.
As described above, the main frame 4 maintains a structure that is not easily affected by external vibrations due to the action of the first elastic member 2. The vibration is suppressed by the dynamic vibration absorbing action constituted by the sub-frame 32 and the second elastic member 31, and the reading of information from the optical disk 10 by the pickup 5 can be performed accurately even when the optical disk 10 rotates at high speed.
FIG. 3 is a diagram showing a vibration model of the optical disk reproducing apparatus according to the present invention. In FIG. 3, portions common to FIG. 10 are denoted by the same reference numerals, and redundant description is omitted. A motion equation similar to that of FIG. 10 described above can be established from the model of FIG. 3, and the results of a simulation performed by the model of FIG. 3 based on the motion equation are shown in the graphs of FIGS.
FIGS. 4 and 5 show simulation results when the mass m of the sub-frame 32 is changed with the resonance frequency kept constant at 120 Hz. 4 and 5 show the respective vibration accelerations of the main frame 20 and the housing with respect to the rotation number of the optical disk when the optical disk imbalance is 0.5 g-cm, and the mass of the sub-frame 32 is 10 g, 20 g. , 40 g. 4 and 5, when the mass of the sub-frame increases, mainly the rotation speed of 4000 r. p. m. 7000 r. p. m. It can be seen that the effect of suppressing vibration is high in the range of.
From these graphs, it can be seen that the large mass of the main frame 20 is effective in reducing the acceleration of the housing 1 and the main frame 4.
FIGS. 6 and 7 show simulation results when the resonance frequency of the sub-frame 32 is changed while keeping the mass of the sub-frame 32 constant at 30 g. FIGS. 6 and 7 show the vibration acceleration of the main frame 20 and the housing 1 with the optical disk imbalance of 0.5 g-cm, respectively, with respect to the rotational speed of the optical disk, and the resonance frequency of the subframe 32 is 100 Hz, 110 Hz, and 130 Hz. These are the results calculated for each case. From FIG. 6 and FIG. 7, the frequency f0 is slightly higher than the rotation frequency to be controlled, that is, the rotation speed is set to 6000 rpm. p. m. If it is set to f0 = 110 Hz, the number of rotations is 7000 r. p. m. It can be seen that if f0 = 130 Hz, a good anti-vibration effect can be obtained.
FIG. 8 shows measured values of characteristic examples of the embodiment according to the present invention using the subframe 32 as a dynamic vibration absorber. This figure is a graph showing the acceleration of the housing with respect to the rotation speed of the optical disk when the optical disk imbalance is set to 0.5 g-cm. The points indicate the case where the dynamic vibration absorber is not used.
As can be seen from FIG. p. m. Thus, the housing G value is 0.07 G when the sub-frame 32 is mounted, and 0.27 G when the sub-frame 32 is not used, indicating that the G value is reduced. Here, assuming that the number of rotations is R (rpm) per minute, f = R / 60, and 6000 r.p.m. p. m. Corresponds to f = 100 Hz.
Due to the above-described simulation and restrictions on the arrangement of the structural members, the weight of the subframe including the subframe or its mounted material is 1/10 to 1/1/1 of the total weight of the main frame and its mounted members. It is preferable to set the number to 3 in order to suppress the vibration of the main frame due to the high-speed rotation of the optical disk or the like, and the sub-frame may be further provided with a metal plate or the like for the purpose of adjusting the mass. Of course, it is possible to obtain the effect without mounting anything.
Further, since the optical disc reproducing apparatus requires a thin apparatus because of conditions such as when the apparatus is built in a computer apparatus, the above-described sub-frame block needs to be configured to be thin, and its shape is flat. It is preferably in the form. Further, it is preferable that the subframe is made of metal from the viewpoint of mass.
Further, by making the plane of the sub-frame block perpendicular to the rotation axis of the spindle motor, the sub-frame block has a vibration suppressing effect on the rotation of the optical disk and also has an effect on making the apparatus thinner. It will be.
It is preferable that the elastic member of the second elastic body is made of rubber or resin from the viewpoint of the above-mentioned reduction in thickness and braking effect. The engagement between the elastic body and the frame may be a method of fitting using the elasticity of a resin or a method of bonding with an adhesive, in addition to the mechanical engagement with a screw or the like.
In the optical disk reproducing apparatus according to the present invention, by using the dynamic vibration absorber as described above, the vibration generated from the optical disk, the motor for driving the pickup transfer drive, or the linear motor often used for high-speed reading is generated by the pickup. The influence on the reading performance can be reduced, and the reading performance at high speed rotation of the optical disc can be improved.
Needless to say, the optical disk reproducing apparatus of the present invention is not limited to a device capable of reproducing information from an optical disk, but may have a configuration capable of recording information on the optical disk.
[0051]
As described above, according to the present invention, between the main frame and the mounting surface of the turntable, the first frame is provided with the second frame via the elastic body. Therefore, it is possible to suppress the vibration of the main frame on which the spindle motor for rotating and driving the optical disk is mounted, and to provide an optical disk driving device or a disk reproducing device capable of performing stable reading. Further, since the outer shape of the subframe can be reduced, the optical disk reproducing apparatus can be configured to be thin, and a thin and high-speed optical disk reproducing apparatus can be provided.
[Brief description of the drawings]
FIG. 1 is a plan view showing an optical disk reproducing apparatus according to the present invention.
FIG. 2 is a cross-sectional view showing an optical disk reproducing device according to the present invention.
FIG. 3 is a diagram showing a vibration model of the optical disc reproducing apparatus according to the present invention.
FIG. 4 is a diagram showing a vibration characteristic of the optical disc reproducing apparatus according to the present invention.
FIG. 5 is a diagram showing a vibration characteristic of the optical disc reproducing apparatus according to the present invention.
FIG. 6 is a diagram showing vibration characteristics of the optical disc reproducing apparatus according to the present invention.
FIG. 7 is a diagram showing a vibration characteristic of the optical disc reproducing apparatus according to the present invention.
FIG. 8 is a diagram showing a vibration characteristic of the optical disc reproducing apparatus according to the present invention.
FIG. 9 is a plan view showing an example of a conventional optical disc reproducing apparatus.
FIG. 10 is a diagram showing a vibration model of a conventional optical disc reproducing apparatus.
[Explanation of symbols]
1 housing 2, 31 elastic member 4 main frame 5 pickup 6 turntable 7 spindle motor 8 drive screw 9 stepping motor 10 optical disks 11 a, 11 b guide rail 20 main frame 32 subframe

Claims (3)

A turntable having a mounting surface for mounting an optical disc;
And a first frame on which the turntable is mounted.
A second frame is provided between the placement surface of the turntable and the first frame,
The disk drive device according to claim 1, wherein the second frame is attached to the first frame via an elastic member. The disk drive according to claim 1, wherein:
A spindle motor for rotating the optical disc is mounted on the turntable,
The disk drive device according to claim 1, wherein a center of gravity of the sub-frame block including the second frame is located on a rotation axis of the spindle motor. A disk drive device according to claim 1 or 2,
A housing for supporting the first frame of the disk drive via an elastic member.

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