JPH0664813B2 - Optical disk device - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an optical disk device capable of stably clamping and holding an optical disk recording medium and enabling highly accurate focusing servo control thereof.

[Technical background of the invention and its problems]

Recently, digital recording / reproduction using PCM technology for audio signals has been attracting attention due to its high fidelity. In particular, a system using an optical disc recording medium, so-called a CD (compact disc), in which bits (concavities and convexities having different reflectances) corresponding to digital data are formed on a metal thin film formed on a transparent resin disk has become widespread. This CD system detects a difference in the reflectance of the pits in a non-contact manner by using an optical head having a laser as a light source to reproduce a signal. Therefore, it is an important subject to perform the focusing control of the optical head with respect to the optical disc recording medium with high accuracy, and for this purpose, it is necessary to stably clamp the optical disc recording medium loaded in the apparatus main body.

In the conventional clamping mechanism, an optical disk recording medium 2 loaded on the turntable 1 is recorded by the clamper 3 which moves up and down facing the turntable 1 as shown in FIGS. 1 and 2, for example. It is configured to hold the medium 2. Turntable 1
The clamper 3 holds the optical disk recording medium 2 by sandwiching the central portion (clamping area) of the optical disk recording medium 2 from both sides, and rotationally drives the optical disk recording medium 2.
The clamper 3 is supported by an arm mechanism 4 and moved up and down in response to the loading operation of the optical disk recording medium 2.

However, when the optical disc recording medium 2 is clamped and held in this way, the optical disc recording medium 2 exhibits the vibration frequency characteristic as shown in FIG. This characteristic is an example when the clamper part is forcibly displaced and excited, and generally has a large resonance point near 90 Hz. Moreover, the Q value of the resonance is extremely large. Therefore, when a slight disturbance such as vibration or shock is applied to the device, the optical disk recording medium 2 vibrates greatly at a frequency near the resonance point. This vibration has a great adverse effect on the focusing servo system of the optical head. Especially for in-vehicle optical disk devices,
As shown in FIG. 4, the vibration frequency characteristic of the vehicle body has a large peak near 100 Hz, which is near the resonance point of the optical disk recording medium 2, so that resonance easily occurs and the focusing servo can be performed without vibration countermeasures. It was very difficult to hang. Therefore, conventionally, an optical disk device is supported via a floating mechanism, and a device for preventing the transmission of disturbance to the optical disk device has been devised so far, but there is a problem that the device configuration becomes complicated.

[Object of the Invention]

The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a stable practicability that is stable against external vibrations and shocks and highly stable focusing servo. It is to provide a high optical disk device.

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an optical disc apparatus for optically reading and reproducing information recorded in a recording area of an optical disc, in which a turn that supports and rotates a clamping area of the optical disc. The table and the optical disk have a diameter larger than that of the turntable in order to suppress the vibration due to disturbance by shifting the natural vibration frequency of the optical disk to the high frequency side, and the clamping area of the optical disk is sandwiched from both sides by the turntable. A clamper supporting means for rotatably supporting the clamper so as to be displaceable along the turntable surface, and an anti-vibration pad provided on the entire surface of the clamper on the optical disk clamping surface side. It is characterized by being provided with.

〔The invention's effect〕

Thus, according to the present invention, the Q value of the vibration of the optical disk recording medium clamped by the damper mechanism can be suppressed to a low value over the entire frequency band by the damper action of the vibration-proof pad, and the Q-value can be suppressed against disturbance. It can have a strong structure. In this case, since the anti-vibration pad is not provided on the turntable, the original function of the turntable, that is, the function of transmitting the rotational force to the optical disc recording medium, the function of regulating the tilt of the optical disc recording medium, and the optical disc recording medium. The function of determining the center of can be exhibited well. Therefore, it is possible to realize a structure that is strong against disturbance without impairing the original function of the turntable. By increasing the diameter of the clamper as compared with the turntable, the natural vibration frequency can be increased. As a result, the vibration applied as the disturbance and the resonance frequency of the natural vibration mode of the optical disc recording medium can be shifted, and the vibration of the optical disc recording medium caused by the disturbance can be prevented. Therefore, in combination with the effect of suppressing the Q value of the resonance, it is possible to effectively suppress the vibration of the optical disk recording medium, and it is possible to apply the focusing servo with high stability and easily. Further, since the vibration damping pad is provided on the entire surface of the clamper on the optical disk clamping surface side, it is possible to effectively suppress the vibration of the clamper itself. In addition, there is no practical complication of the apparatus configuration, and the present invention can be applied to the existing apparatus with a simple improvement, and the practically great effect can be obtained.

Example of Invention

 Embodiments of the present invention will be described below with reference to the drawings.

5 to 6 show the essential parts of an optical disk device according to an embodiment of the present invention. The same parts as those of the conventional device shown in FIGS. 1 and 2 are designated by the same reference numerals. There is.
The device of this embodiment is characterized in that an antivibration pad 5 is provided on the optical disk recording medium clamping surface of the clamper 3 for clamping the optical disk recording medium 2 loaded on the turntable 1, and the antivibration pad 5 is used to intervene the antivibration pad 5. The optical disk recording medium 2 is clamped and held. The anti-vibration pad 5 is made of, for example, elastic rubber attached to the entire clamp surface of the optical disk recording medium of the clamper 3, and presses the rear surface side of the signal reading surface of the optical disk recording medium 2 to press the optical disk recording medium 2. Is clamped on the turntable 1. The diameter of the turntable 1 is set to be the same as the diameter of the central clamping area of the optical disc recording medium 2 so as not to hinder the reading of signals from the optical disc recording medium 2. The diameter of the clamper 3 is set larger than that of the turntable 1. That is, the diameter of the clamper 3 is larger than the clamping area on the back side of the signal reading surface of the optical disc recording medium 2, that is, the recorded area, so that the optical disc recording medium 2 can be clamped. It is set larger than the diameter of the innermost track. The clamper 3 provided with such a vibration-proof pad 5 responds to the loading of the optical disk recording medium 2 on the turntable 1 by the arm mechanism 4 as shown in FIGS. The movement is controlled as shown.
Then, the optical disk recording medium 2 is rotationally driven by a motor (not shown) while being clamped by the clamper 3 via the vibration isolation pad 5, and is used for non-contact signal reading by the optical head. At this time, needless to say, focusing servo control of the optical head with respect to the optical disc recording medium 2 is performed.

Thus, according to the present device having the structure in which the damper 3 is provided with the vibration-proof pad 5 as described above, the clamper 3 presses the optical disk recording medium 2 from the back surface side thereof via the vibration-proof pad 5 so that the optical disk recording medium 2 is secured. It will be clamped to the turntable 1. As a result, the damper action of the vibration-proof pad 5 occurs on the clamp surface of the optical disc recording medium 2, and the Q value of the vibration is suppressed to be low over almost the entire band. Therefore, the vibration of the optical disc recording medium 2 itself can be suppressed to be small even if external disturbance such as vibration or shock is applied to the clamped optical disc recording medium 2. Moreover, since the diameter of the clamper 3 is made larger than the diameter of the turntable 1 so as to clamp the optical disc recording medium 2 over a wide range, the natural vibration frequency of the optical disc recording medium 2 is entirely in the high range. Can be moved to the side. As a result, for example, in a vehicle-mounted device, the natural vibration frequency of the vehicle body and the natural vibration frequency of the optical disc recording medium 2 can be shifted, and resonance of the optical disc recording medium 2 due to vehicle body vibration can be prevented. Becomes Therefore, in combination with the reduction of the Q value of the vibration, it is possible to effectively suppress the vibration of the optical disk recording medium 2 caused by the disturbance or the like, and it is possible to stably perform the focusing servo.

Further, since the antivibration pad 5 is provided on the entire clamp surface of the optical disk recording medium of the clamper 3, the vibration of the clamper 3 itself can be effectively suppressed, and the optical disk recording medium 2 is vibrated by the vibration of the clamper 5 itself. It is possible to avoid the fear.

Further, since no vibration damping pad is provided on the surface of the turntable 1, the original function of the turntable 1 will not be impaired.

By the way, some recording media 2 have minute protrusions 2a formed between the recorded area and the clamping area as shown in FIG. When clamping the optical disk recording medium 2 as described above, if the surface of the vibration isolation pad 5 is flat, the optical disk recording medium 2 cannot be stably pressed and clamped over the entire clamp surface.
Therefore, in such a case, the recess 5a may be formed in a portion of the vibration-proof pad 5 that faces the minute protrusion 2a. By providing the vibration-proof pad 5 with such a structure, it becomes possible to clamp the optical disk recording medium 2 while avoiding the minute protrusions 2a in the recess 5a,
The stabilization can be achieved. Moreover, the minute protrusions
Even for the optical disk recording medium 2 not provided with 2a, the stable clamping is not hindered. Further, as shown in FIG. 8, the vibration-proof pad 5 may be structured to have a plurality of protrusions 5b having the same height, and the optical disc recording medium 2 may be clamped discretely over a wide range. That is, as shown in FIGS. 9 and 10, respectively, the vibration-proof pad 5 may be formed with minute protrusions or concentric protrusions having the same height. Even if the antivibration pad 5 having such a structure is adopted, the same effect as that of the previous embodiment can be obtained.

As described above, according to the present invention, since the vibration damping pad 5 is provided on the clamp surface of the clamper 3, the vibration of the clamped optical disk recording medium 2 is effectively exerted without adversely affecting the function of the turntable 1. Can be effectively suppressed. Therefore, it is possible to obtain a practically great effect of enabling stable focusing servo control and the like. Therefore, the optical disk recording medium 2 is always stable.
It is possible to read the signal from the.

The present invention is not limited to the above embodiment. For example, turntable 1, clamper 3 and anti-vibration pad 5
The diameter may be determined according to the specifications of the optical disc recording medium 2. Further, the damper characteristics and the like of the vibration-proof pad 5 may be determined according to the specifications. Specifically, in the case of a normal so-called CD (compact disc), the antivibration pad 5 is set to neoyaprene, SBR
(Butadiene-styrene copolymer), NBR (butadiene acrylonitrile copolymer), or other rubber material, or sponge rubber or felt may be used. In short, the present invention can be implemented with various modifications without departing from the gist thereof.

[Brief description of drawings]

1 and 2 are diagrams showing a configuration of a conventional device, FIG. 3 is a diagram showing a vibration frequency characteristic of an optical disc recording medium in the conventional device, and FIG. 4 is a vibration frequency characteristic of a vehicle body on which the optical disc device is mounted. FIG. 5, FIG. 5 and FIG. 6 are configuration diagrams of a main part showing an embodiment of the present invention, and FIGS. 7 to 10 are diagrams showing a configuration example of a vibration-proof pad. 1 ... Turntable, 2 ... Optical disc recording medium, 3
…… Clamper, 4 …… Arm mechanism, 5 …… Vibration-proof pad.

Claims (4)

[Claims] 1. An optical disk apparatus for optically reading and reproducing information recorded in a recording area of an optical disk, comprising: a turntable which supports and rotates a clamping area of the optical disk; and a natural vibration frequency of the optical disk. A clamper which has a diameter larger than that of the turntable in order to suppress vibration due to disturbance by shifting to the zone side, and which clamps the clamping area of the optical disk from both sides with the turntable, and the clamper is rotatable. In addition, an optical disc comprising: a clamper supporting means for supporting the turntable surface so as to be displaceable along the turntable surface; and an anti-vibration pad provided on the entire surface of the clamper on the optical disk clamp surface side. apparatus. 2. The anti-vibration pad has a plurality of protrusions having the same height, and the tips of the protrusions are contact surfaces to the optical disc, respectively. Optical disk device. 3. The optical disk device according to claim 2, wherein the plurality of protrusions are discretely formed on the surface of the anti-vibration pad. 4. The optical disk device according to claim 2, wherein the plurality of protrusions are concentrically formed on the surface of the vibration-proof pad.