JPH07109665B2 - Optical disk center hole processing equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is provided in the central portion of an information carrier disc (hereinafter referred to as an optical disc) in which two disc-shaped substrates having a recording medium layer on at least one surface are stuck together. Center hole (a hole that serves as the center of rotation during recording / playback).

Structure of conventional example and its problems In the optical recording / reproducing method, the recording medium layer of the optical disc is irradiated with a laser beam corresponding to an information signal to record / reproduce information by providing optical density or unevenness on the recording medium layer. This is a method that can record a minute signal of several μm, and in principle is a method that enables high-density recording of about the wavelength of light. In addition, since this optical recording / reproducing system does not contact the pickup for recording / reproducing signals during recording / medium and the optical disc, it does not wear, and provides multiple functions such as still images and high-speed search. etc,
It is being put to practical use for industrial and commercial purposes.

Conventionally, the optical disk has a recording medium layer provided on one surface of a disk-shaped transparent substrate, or a predetermined information signal recorded as concave and convex bits so that the surfaces provided with the recording medium layer face each other. Alternatively, two protective substrates are attached to the ends so as to face the recording medium layer, and information is recorded / reproduced by irradiating a laser beam from the substrate surface. As a transparent substrate for these optical discs, resin materials such as cast acrylic and polycarbonate are generally used in consideration of economical efficiency, safety and optical characteristics.However, these resin materials are distorted by changes in humidity and temperature. It has the property to occur. For this reason, the two optical disks that have been bonded together have strain on the two substrates with respect to changes in humidity and temperature during use, resulting in sudden changes in humidity and temperature during long-term humidity and temperature cycles or during transportation. There was a problem that peeling is likely to occur. Further, there is a problem that peeling occurs even with a mechanical shock.

The structure of a conventional optical disc is shown in FIG. An ultraviolet curable resin layer 2 for forming a signal track is provided on one surface of a disk substrate 1, and a recording medium layer 3 is formed thereon.
Further, in order to protect the recording medium layer 3, a protective substrate 5 is bonded via an adhesive layer 4.

In the case of such a structure, peeling is likely to occur particularly from the outer peripheral end face and the center hole end face due to the above-mentioned changes in humidity and temperature, mechanical shock, etc. There is a risk that peeling will progress.

Therefore, a method of improving mechanical bonding strength by forming a cured coating material layer [for example, an acrylic ultraviolet curing agent] at the end of the bonding surface for the purpose of protecting the surface of the optical disk has been conventionally used. There is. The state of formation of this conventional cured coating layer is shown in FIG. 2 and FIG. In FIG. 2, 6 is a sensor hole of the optical disk, 7 is a coating layer of a surface hardening material that protects the surface of the recording area, and is formed so as to surround the outer peripheral edge of the optical disk. Reference numeral 8 denotes a cured coating material layer formed on the entire circumference of the end surface of the center hole 6. With the above configuration, the optical disk substrate 1 and the protective substrate 5 are mechanically fixed, which is sufficient as a measure against peeling. However, the diameter and shape of the center hole may change significantly depending on the state of the hardened coating material layer formed on the end face of the center hole 6 and the thickness of the coating.

Therefore, as shown in FIG. 3, an annular groove 9 is formed in the end face of the center hole 6.
It was necessary to fill the annular groove 9 with the cured coating material 8 to absorb the influence of the rise and uneven thickness of the cured coating material. This makes it possible to maintain the center hole machined to have a predetermined positional accuracy and hole diameter, and improve the bonding strength.

That is, after assembling the optical disk [bonding the optical disk substrate and the protective film substrate], a center hole having a predetermined hole diameter is overhauled to the center of the signal track described above, and a hardened coating material filling annular groove is provided at the center of the end face of the center hole. The need arose.

In the conventional center hole processing, after finishing a cylindrical center hole at a predetermined position with a predetermined hole diameter, the optical disk is rotated by a processing machine such as a lathe to process the annular groove 9. There is a problem in terms of efficiency and man-hours, and the current situation is that stable and highly efficient machining cannot be realized.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical disk center hole processing apparatus capable of processing the center hole of an optical disk at the center of a track signal and efficiently and stably processing the center annular portion of the center hole in the plate thickness direction. .

The optical disk center hole drilling apparatus of the present invention comprises a rotating blade, a track center detecting means for detecting the center of a signal track of an optical disk, and a rotation center of the blade controlled by a signal from the track center detecting means. The center of the signal track of the optical disk is moved relative to the blade and the optical disk by X-
XY driving means for driving and matching in the Y direction, and axial cutting means for driving the blade and the optical disk relative to each other in the rotational axis direction of the blade to give an axial cut to machine the center hole of the optical disk. And a substantially sinusoidal movement command having a phase difference of 90 ° to the XY driving means.
It has a radial cutting means for giving it in the Y-axis direction, and an annular groove can be easily provided in the center of the center hole simply by setting the optical disk to be processed, and both ends of the center hole are finished to a predetermined center hole diameter. It is characterized by being able to.

Description of Embodiments Embodiments of the present invention will be described below with reference to FIGS. 4 to 7.

FIG. 4 shows an embodiment of the present invention. 10 is an optical disc,
It is held on the vacuum suction table 11. X table 12, Y table 13, Z table 14 under the vacuum suction table 11
3 axis drive means is provided. X, Y, Z tables 1
2, 13 and 14 are driven by pulse motors, respectively. 1
5, 16 and 17 are pulse motor drivers for the X, Y and Z axes, and 18 is a center hole cutting tool having a convex cutting edge, which is attached to a spindle 19 and is given a constant rotation by a motor 20. ing. The center hole processing blade 18 is set to a predetermined protrusion amount for processing a predetermined center hole diameter d.
At least three line sensor cameras 21 are provided as signal track detecting means. In this embodiment, four lines are used and one pair is arranged in the X and Y directions to detect the outermost circumference of the signal track [only two lines are shown in the figure]. 22 is a microcomputer for controlling each part. The center hole is machined by using the machine having the above structure.

The configuration of the microcomputer 22 will be described in detail according to the processing procedure / operation.

The optical disk 10 is held by the vacuum suction table 11, and the Z table 14 is raised so that the line sensor camera 21 is focused on the signal track (outermost peripheral portion) provided on the optical disk 10. The center of the signal track is obtained by the line sensor camera 21. The center of the signal track obtained by the line sensor camera 21 is taken as X-
Match by Y tables 12 and 13. Next, the motor 20
The spindle 19 and the blade 18 are rotated by a certain amount to raise the Z table 14, and the blade 18 is cut to the center of the end face of the center hole as shown in FIG. As a result, the center hole end face portion 23 is finished to have a predetermined hole diameter do. After the cutting edge of the blade 18 reaches the center of the end face of the center hole, the X table 12 is moved in the outer peripheral direction of the optical disc 10 by a predetermined amount a (a is the depth of the annular groove 9 to be formed on the end face of the center hole). Further X, Y table 12,
13 is moved by a substantially sine wave having a phase difference of 90 ° from each other. That is, as shown in FIG. 6, the X axis is driven by the following equation after feeding the annular groove 9 by a predetermined depth a.

X = a · sin [ωt + (π / 2)] On the other hand, the Y-axis is calculated by the following equation having a phase difference of 90 ° with respect to the x-axis after the X-axis has sent a predetermined depth a of the annular groove 9. Driven.

Y = sin ωt As a result, the center of the center hole of the optical disk placed on the X, Y tables 12 and 13 draws a circle. As a result, the annular groove 9 can be formed in the end face of the center hole 6 as shown in FIG. 5b. The cross-sectional shape of the annular groove 9 differs depending on the shape of the cutting edge of the cutting tool 18 used.

By driving the X, Y tables 12, 13 as described above, the center of the center hole 6 draws a circle to form the annular groove 9 on the end face of the center hole 6, and then the X table 12 is moved by a predetermined amount (-a). This state has the same positional relationship as when the end portion 23 of the end face of the center hole 6 was machined to have a predetermined center hole diameter d.

Next, the Z table 14 is raised, and the upper end 23 'of the center hole 6 is machined to have a predetermined center hole diameter d. As a result, an annular groove 9 is formed at the center of the end face of the center hole 6 as shown in FIG. 5C, and both ends 23, 23 'can be continuously and easily finished to have a predetermined center hole diameter d.

In this embodiment, when the annular groove is formed, the groove depth a is sent in the uniaxial direction, and then the X and Y axes are driven by substantially sinusoidal waves having a phase difference of 90 °. As shown, the amplitude of the substantially sine wave having a phase difference of 90 ° may be gradually increased to form the annular groove 9 having a predetermined depth. In the case of FIG. 7, when the amplitude of the substantially sine wave is E when the cutting edge is at the end of the center hole and C when it is at the center, C> E ≧ O. It is determined.

Further, both ends of the center hole end face to be machined to have a predetermined center hole diameter d may be machined by being driven by the above-mentioned substantially sine wave. That is, the center hole end face central portion may be machined by driving with a substantially sine wave having an amplitude (corresponding to the annular groove depth) larger than the amplitude of the substantially sine wave at the time of processing both end portions of the center hole end surface.

Furthermore, the initial setting of the center hole cutting tool (projection amount) and the correction of the projection amount of the tool due to wear of the tool can be facilitated by changing the amplitude of the above-mentioned approximately sine wave, and at the same time no adjustable tool mounting tool is required. The center hole machining blade mounting part can be made compact.

Further, in the above-mentioned embodiment, the method of forming the annular groove in the center of the end face of the center hole continuously with the predetermined center hole machining is adopted. It is also possible to dispose the cutting edge of the cutting tool in the central portion and process the annular groove according to the method for forming the annular groove described above.

As described above, according to the optical disk center hole drilling apparatus of the present invention, since the track center detecting portion, the XY driving means, the axial cutting means and the radial cutting means are provided, the optical disk center hole is formed. The hole can be machined in the center of the signal track, and the surface hardening material filling annular groove can be continuously and easily provided at the center of the end surface of the center hole, which can significantly improve the man-hours and efficiency compared with the conventional method. .

[Brief description of drawings]

FIG. 1 is a front sectional view of a conventional optical disc, FIG. 2 and FIG.
FIG. 4 is a front sectional view of an optical disk having a bonding strength improving measure, FIG. 4 is a schematic configuration diagram showing an embodiment of a processing apparatus according to the present invention, and FIGS. 5a, 5b and 5c are center hole processing according to the present invention. FIG. 6 is a sectional view showing a state, FIG. 6 is an explanatory diagram of a radial movement state of the XY driving means in the present invention, and FIG. 7 is an explanatory diagram of another embodiment of FIG. 6 ... Center hole, 8 ... Hardened film material, 9 ... Annular groove, 10
...... Optical disc, 11 ... Vacuum adsorption table, 12,13,14 ...
… X, Y, Z table, 18 …… Center hole drilling tool, 21 ……
Line sensor camera [track center detection means], 22 ……
Microcomputer

Claims (2)

[Claims] 1. A rotating blade, track center detecting means for detecting the center of a signal track of an optical disc, and a signal center of the optical disc at the center of rotation of the blade controlled by a signal from the track center detection. X- that drives the blade and the optical disk relatively in the X-Y directions to match them
Y driving means, axial cutting means for driving the blade and the optical disk relative to each other in the rotational axis direction of the blade to give an axial cut to machine the center hole of the optical disk,
An optical disk center hole drilling device having: -Y drive means for giving a substantially sinusoidal movement command having a phase difference of 90 ° to each other in the X-Y axis direction; 2. When the shape of the cutting edge of the blade is convex and the amplitude of the substantially sine wave of the radial cutting means is E when the cutting edge is at the end of the center hole and C when it is at the center. ,
Claim 1 wherein C> E ≧ 0
The optical disk center hole drilling device described in the item.