JPH10188364A - Balance correcting device for optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the device for correcting an unbalanced load (mass eccentricity) on the rotational center of the optical disk. SOLUTION: The direction and size of an unbalanced load are measured by an unbalanced load measuring device 1 in rotating the optical disk OD with rotation angle information from an angle sensor 6 and distortion amt. information of a rotary shaft 5 from a gap sensor 7. Based on the direction and size of the measured unbalanced load, position control and operation control of an ink discharger 15 are performed to apply a printing ink as a weight on the optical disk OD by a weight attaching device 11 to cancel the unbalanced load.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a CD-Audi.
o, Correction of an optical disc balance used for correcting an eccentric load (eccentricity) with respect to a rotation center of an optical disc which is a disc-shaped optical information recording medium such as a CD-ROM, a CD-R, a CD-E, and a DVD. Related to the device.

[0002]

2. Description of the Related Art Generally, CD-Audio, CD-RO
Optical disks such as M, CD-R, CD-E, and DVD are formed by an injection molding method using a stamper, and a reflective film is deposited on a plastic substrate on which information is recorded, a protective film is formed, a label is printed, and the like. It is manufactured by processing. In the optical disc manufactured in this way, if the entire plastic substrate cannot be uniformly molded in the injection molding process,
It is known that an eccentric load (eccentric center) occurs with respect to the rotation center of the optical disk.

Further, it has been found that an eccentric load is also generated by label printing on an optical disk. Label printing
Usually, in order to indicate the name of the optical disk, the content of the recorded information, and the like, the surface of the single-sided recording disk is not irradiated with the recording / reproducing laser beam, but the distribution of the printing ink is within the surface. It is non-uniform due to the presence or absence of printing, shading, and the like, which is also considered to be a factor that causes an uneven load on the optical disk.

It has been pointed out that, when an optical disk having an offset load is rotationally driven by a reproducing apparatus or the like, internal vibration occurs due to dynamic imbalance caused by the offset load, and the reproduction quality of information signals is impaired. Hitherto, in order to solve the above-mentioned inconveniences, it has been proposed to improve the reproduction device and the like (Japanese Patent Application Laid-Open Nos. 3-273590 and 4-273590).
-17184 gazette).

[0005]

However, since the degree of the eccentric load on each optical disk is different from each other, measures are taken on the optical disk side during the manufacturing of the optical disk, rather than on the reproduction apparatus or the like to take measures to solve this. It is easier and more reliable to correct the eccentric load to suppress vibration during rotation.

SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to provide an optical disk balance correcting apparatus used for correcting an eccentric load (eccentricity) with respect to the rotation center of an optical disk.

[0007]

Therefore, according to the first aspect of the present invention, an optical disk can be set, and by rotating the optical disk, the direction and magnitude of the eccentric load with respect to the rotation center can be determined from the bending state of the rotating shaft. An unbalanced load measuring device for measurement and a weight attachment device for attaching a weight to the optical disc so as to cancel the measured unbalanced load are provided to constitute an optical disc balancing correction device.

That is, when the optical disk is rotated at a high speed, if the optical disk has an eccentric load, the optical disk rotates in the direction of the eccentric load with the deflection of the rotating shaft. Proportional. Therefore, if the direction and magnitude of the eccentric load are measured from the bending state of the rotating shaft, and a weight is attached based on the measurement result so as to cancel the direction, the eccentric load can be eliminated.

In the invention according to claim 2, the offset load measuring device includes an angle sensor for detecting a rotation angle of the optical disc, and a gap sensor for detecting a distance from the peripheral surface of the rotating shaft to the peripheral surface. Is characterized by including. During one rotation, when the distance from the circumferential surface of the rotating shaft detected by the gap sensor is minimized, the direction of the eccentric load can be detected by the rotation angle detected by the angle sensor. This is because the magnitude of the eccentric load can be measured from the output.

[0010] In the invention according to claim 3, the weight attachment device is provided based on the direction and magnitude of the measured eccentric load.
It is characterized in that a weight corresponding to the magnitude of the eccentric load is attached on a line in the direction opposite to the direction of the eccentric load. This is because it is easiest to attach in the direction opposite to the direction of the eccentric load, that is, in the direction 180 ° out of phase. In the invention according to claim 4, the weight attaching device has a weight setting unit that changes at least one of an amount of the attached weight or a radial position from the rotation center in accordance with the magnitude of the eccentric load. It is characterized by having. This is because the moment is determined by the amount of the weight and the distance from the rotation center.

The invention according to claim 5 is characterized in that the weight applying device applies a printing ink as a weight. The invention according to claim 6 is characterized in that the weight attaching device attaches a seal as a weight. In any case, if the color and the shape are taken into consideration, the quality of the optical disc as a commercial product is not impaired.

In the invention according to claim 7, the weight attachment device is arranged above an optical disk set in the offset load measuring device. Thus, both devices can be compactly assembled.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the illustrated one. FIG. 1 shows an embodiment. The eccentric load measuring device 1 includes a set portion 3 for the optical disc OD on the upper surface of the main body 2 and a rotation shaft 5 driven by a motor 4 to rotate the optical disc OD at the center of the set portion 3. I have.

The eccentric load measuring device 1 also includes an angle sensor (rotary encoder) for outputting a signal corresponding to the rotation angle of the motor 4 (therefore, the rotation angle of the optical disk OD).
6 and a gap sensor 7 that outputs a signal corresponding to the distance from the peripheral surface of the rotating shaft 5 to the peripheral surface.
The eccentric load measuring device 1 further includes an arithmetic unit 8 to which signals from the angle sensor 6 and the gap sensor 7 are input. The arithmetic unit 8 includes a rotation control unit 9 for controlling the rotation of the motor 4 and an eccentric load. Offset load calculation means 10 to be calculated
And

A weight attachment device 11 is disposed above the optical disc OD set in the offset load measuring device 1. The weight attaching device 11 includes a motor 12 that can be moved up and down by an elevating device (not shown), and one end attached to a downward rotating shaft 13 (having the same axis as the rotation center of the optical disk OD). It has a guide rod 14 that rotates on a parallel plane, and a downward ink ejector (dispenser) 15 slidably mounted on the guide rod 14.

The weight applying device 11 further includes an arithmetic unit 16, which sets the position and amount of ink to be applied as a weight based on the eccentric load calculated by the eccentric load calculating means 10. The apparatus includes a weight setting unit 17 and an attachment control unit 18 that controls the position and the operation of the ink ejector 15 according to the setting. Next, the operation will be described.

After setting the optical disk OD on the rotating shaft 5 of the offset load measuring device 1, the motor 4 is operated to rotate the optical disk OD at high speed. The rotation speed at this time is controlled by the rotation control means 9 to a predetermined constant value. In this manner, when the optical disc OD is rotated at a high speed, if the optical disc OD has an eccentric load, as shown in FIG. The amount of deflection is substantially proportional to the magnitude of the eccentric load W.

Therefore, during one rotation, when the distance from the circumferential surface of the rotating shaft 5 detected by the gap sensor 7 becomes minimum, the direction of the eccentric load is detected by the rotation angle θ detected by the angle sensor 6. The magnitude F (g · mm) of the eccentric load can be measured from the output of the gap sensor 7 at that time. Therefore, the eccentric load calculating means 10 calculates the eccentric load direction θ and the magnitude F based on the signals from the angle sensor 6 and the gap sensor 7, and calculates the eccentric load.
Send to

Incidentally, the measurement of the eccentric load based on such a principle is as follows.
A commercially available vertical single-sided balance tester (Akasi Corporation: A
V-116B). After the measurement of the unbalanced load, the motor 4 is stopped at the fixed position, the optical disk OD is returned to the reference angle position, and the control flow is shifted to the weight attaching device 11 side. In the weight attachment device 11, when the direction θ and the magnitude F of the eccentric load are calculated, the weight setting unit 17
Based on the offset load direction θ, the weight attachment position in the circumferential direction is set to θ + 180 ° or θ−180 ° in order to attach the weight on a line opposite to the offset load direction θ.

Further, the amount of the attached weight and the radial position from the rotation center are set in accordance with the magnitude F of the eccentric load. Specifically, assuming that the specific gravity of the weight is γ, the weight amount v
Is constant, the radial position d is set to d = F / (γ · v). Alternatively, assuming that the radial position d is constant, the weight v = F / (d · γ) is set. In response to this setting, the attachment control means 18 rotates the motor 13 to the attachment position (θ + 180 ° or θ−180 °) in the circumferential direction of the weight, and moves the ink discharger 15 on the guide rod 14 to the radius of the weight. To the attachment position d in the direction. Then, at this position, the ejector 15 is operated by a pulse or the like, and the amount v of ink is applied (applied) onto the optical disk OD.

As a result, it is possible to balance the optical disc OD while eliminating the eccentric load. As the weight, a printing ink may be used, or a sticker may be attached. That is, as shown in FIG. 3, a strip-shaped sealing member 31 wound around a roll is pulled out and used, and a circular cut is made in advance in the sealing member 31, and the sealing member 31 is pressed by a pressing rod 32 to form a seal. May be attached.

In this way, even if a weight is attached, there is no problem in inputting / outputting information as long as the recording / reproducing laser beam of the optical disk is not irradiated. However, since it can be added to the surface not irradiated with the recording / reproducing laser beam, there is no problem at all. There is no particular limitation on the material of the weight, but a weight using a material having the same optical characteristics as the substrate of the optical disk may be added to the surface irradiated with the recording / reproducing laser beam.

Further, if it is transparent to visible light, it is convenient that even if it is added on a label, there is little risk of affecting its design and the described contents are not hidden. Regarding the control of the weight attachment position in the weight attachment device 11, the ink ejection device
The position may be determined by rotating the optical disk OD by the motor 4 of the biased load measuring device 1 without rotating the optical disk 15.

Further, on the weight attachment device 11, the attachment position on the XY coordinate is obtained, and the ink ejection device is determined on the XY coordinate.
The position control of 15 may be performed.

[0025]

As described above, according to the first aspect of the present invention, the direction and magnitude of the eccentric load with respect to the rotation center are measured from the bending state of the rotating shaft by rotating the optical disk. Since the weight can be attached so as to cancel the measured offset load, the offset load can be eliminated.

According to the second aspect of the present invention, the direction and magnitude of the eccentric load can be accurately measured using the angle sensor and the gap sensor. According to the third aspect of the present invention, the weight can be easily implemented by setting the attachment position of the weight on a line opposite to the direction of the eccentric load. Claim 4
According to the invention according to the first aspect, it is possible to completely eliminate the unbalanced load by changing the amount of the attached weight or the radial position according to the magnitude of the unbalanced load.

According to the fifth aspect of the present invention, the printing ink is used as the weight, and according to the sixth aspect of the present invention, the seal is used as the weight. In consideration of the above, there is no loss of the quality of the optical disc as a product. According to the invention according to claim 7, the unbalanced load measuring device and the weight attaching device can be compactly assembled.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

Fig. 2 Principle diagram of the eccentric load measurement

FIG. 3 is a diagram showing a modification of weight attachment;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Unbalanced load measuring device 4 Motor 5 Rotary axis 6 Angle sensor (rotary encoder) 7 Gap sensor 8 Operation unit 9 Rotation control means 10 Unbalanced load calculation means 11 Weight attachment device 12 Motor 14 Guide rod 15 Ink ejector 16 Operation unit 17 Weight Setting means 18 Attachment control means

Claims (7)

[Claims] An optical disk can be set, an optical disk is rotated, and an eccentric load measuring device for measuring an eccentric load direction and a magnitude of an eccentric load with respect to a rotation center from a bending state of a rotating shaft, And a weight attachment device for attaching a weight so as to cancel the biased load. 2. The apparatus according to claim 1, wherein the offset load measuring device includes an angle sensor for detecting a rotation angle of the optical disk, and a gap sensor for detecting a distance from the peripheral surface of the rotating shaft to the peripheral surface. 2. The apparatus for correcting a balance of an optical disk according to claim 1, wherein: 3. The weight attachment device according to claim 1, wherein a weight corresponding to the magnitude of the eccentric load is attached on a line in a direction opposite to the direction of the eccentric load based on the measured direction and magnitude of the eccentric load. 3. The optical disk balancing correction device according to claim 1, wherein: 4. The weight attachment device has weight setting means for changing at least one of an amount of the attached weight or a radial position from the rotation center in accordance with the magnitude of the unbalanced load. 4. An optical disk balance correcting device according to claim 3, wherein: 5. The weight applying device according to claim 1, wherein the weight applying device applies a printing ink as a weight.
An apparatus for correcting a balance of an optical disk according to claim 1. 6. The apparatus according to claim 1, wherein said weight attaching device is a device for attaching a seal as a weight. 7. The balance for an optical disk according to claim 1, wherein the weight attachment device is disposed above an optical disk set in the eccentric load measuring device. Correction device.