JPH0454302B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for accurately cutting out a digital disk such as an audio compact disk from a substrate.

[Conventional technology]

Recently, optical, magnetic, and magneto-optical digital disks have been used as a means of recording information, such as compact disks for audio, computers, etc.
It has come to be widely used as an external recording disk for OA equipment.

These digital disks record digital information by changing the direction of magnetization and light reflection in response to recording signals.
During reproduction, these changes are detected magnetically or optically, and these changes are converted into electrical signals and read.

Traditionally, in order to manufacture digital disks,
The disks for the disks were molded one by one using resin injection molding, etc., and various processes such as writing digital information on the disks were performed to create the finished product. For example, in the case of an audio compact disc, which is a typical optical digital disc, a glass master is created with multiple concave parts corresponding to the digital signals from a digitally edited digital tape master, and the corresponding convex parts are created from the glass master. A metal stamper having a section is manufactured, this stamper is assembled into a molding machine, and a polycarbonate disc is manufactured by injection molding or the like. Therefore, on the obtained disk, a plurality of pits corresponding to the convex portions of the stamper are arranged in a spiral shape with a track pitch of 1.6 μm, and digital information has already been recorded by this pit row. A reflective film of aluminum or the like is formed on this disc by vapor deposition or the like, and a protective film is formed thereon to complete the compact disc.

In such conventional manufacturing methods, manufacturing the stamper is troublesome, and the disks that will become the digital disks are individually molded by injection molding or compression molding, resulting in extremely high costs.

Due to these circumstances, multiple spiral pit rows corresponding to a single digital disk are created on a single board using printing or other techniques, and then multiple digital disks are cut out from the single board. A method of turning it into a product is being considered.

However, since there are no markings for cutting out a board with only micron-sized pits, the inner and outer peripheries of the board are machined using a router or similar tool so that the inner and outer peripheries are within specified dimensions and tolerances. It is extremely difficult to process and cut out digital discs.

[Problem that the invention seeks to solve]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for cutting out a digital disk from a substrate on which digital information has been written in advance, by which the center hole and the outer periphery of the digital disk can be cut concentrically with the center of the pit row with high accuracy. do.

[Means for solving problems]

The digital disk cutting method of the present invention is a method using a laser, in which the pit row of a substrate on which digital information is recorded is detected by a spiral pit row, and the vortex of the pit row is detected from the detected pit row. The center point is determined, and while rotating at least one of the substrate and the laser beam around the determined center point of the vortex of the pit row, the innermost and outermost pit rows of the digital information recording area consisting of the pit rows are determined. By irradiating at least one of the outer sides of the digital disk with a laser beam, at least one of the center hole and the outer periphery of the digital disk is cut concentrically from the substrate to the row of pits.

There are no limitations on the external shape of the substrate to which the method of the present invention is applied, as long as it has a row of pits as digital information. Therefore, in addition to a substrate in which pit rows are formed by a technique such as printing, a substrate formed by conventional injection molding or injection compression molding may be used.

As the laser to be used, a carbon dioxide laser, a YAG laser, an excimer laser, etc., which are used for ordinary cutting, etc. can be used.

CD
Various optical or magnetic methods that have been put into practical use for locating digital discs in players and OA equipment can be employed.

In addition, to find the center of a spiral pit row from the detected pit row, it is possible to calculate it mathematically from the curvature of the detected pit row, or to calculate it geometrically by detecting the pit row multiple times at different locations. You can also find the center of .

For example, a substrate on which digital information is recorded is rotated, and a given pit in a row of pits is rotated by 90°, 180°, and 270°, and the deviation is detected at different positions using a microscope with a scale. From this displacement, the center of the pit row can be found by performing arithmetic calculations. Also, move the microscope etc. in any direction from end to end to find the number of rows of pits crossed, and then move the microscope from end to end again at right angles from the center of the row of pits that were crossed. If you find the number of rows of pits, the center will be the center of the row of pits.

If such detection and calculation are performed using an optical measuring device and a computer, it is possible to determine the center of the pit row with high precision in a short time.

[Effect]

In this method, in order to determine the positions of the inner and outer peripheries to be cut into a digital disk, the center point of the pit row is determined by using the spiral pit row that has already been formed as digital information on the board. The central hole and outer periphery of the digital disk at a defined distance from the point are cut simultaneously or separately with a laser. Therefore, even if the dimensions of the substrate and the position of the digital information recording area formed on the substrate are not precisely aligned, it is possible to easily and accurately cut a digital disk from the substrate with a specified precision. It is possible to take out.

Note that both the center hole and the outer periphery may be cut with a laser based on the optically determined center point of the pit row, but if only one of them is cut with a laser, the remaining outer periphery or the center hole will be cut. It is also possible to cut mechanically based on the laser cut center hole or the outer periphery.

〔Example〕

As shown in FIG. 2, a spiral-shaped pit row 2 is arranged in the longitudinal direction of the substrate 1, from the innermost pit row 3 to the outermost pit row 4, on a 1.2 mm thick polycarbonate long plate-shaped substrate 1. A plurality of them have already been formed along the same lines. For each digital information recording area 5 composed of all pit rows 2, an aluminum reflective film 6 is formed to cover all the pits, and a resin protective film (not shown) is further formed on the entire surface. It has been formed.

The part covered with one reflective film 6 is cut off from this elongated plate-shaped substrate 1, and the cut-off substrate 1 is
As shown in FIG. 1, it was set on a rotary table 7 that could be rotated by a drive motor 8 and a drive belt 9. After aligning the center of the scale of the scaled microscope 10 with one pit of the innermost pit row 3, turn the rotary table 7 at 90 degrees.
It was rotated 180° and 270°, and the deviation of the innermost pit row 3 at each position was measured using a scale. By moving the substrate 1 in the opposing direction by 1/2 of the amount of deviation at the opposing positions, the center point of the pit row 2 and the rotation axis of the rotating table 7 were brought into alignment.

Next, a CO ₂ laser light source 11 is installed at a position a distance from the rotation axis of the rotary table 7, that is, the center point of the pit row 2, to the determined inner circumference (inside the innermost pit row 3). While rotating the turntable 7, the substrate 1 was irradiated with a laser beam 12a having a wavelength of 10.6 μm and an output of 25 W to cut the inner circumference. The same laser light source 11 is moved to a position a distance from the center point of the pit row 2 to the determined outer periphery (outside the outermost pit row 4), and the laser beam 12b is irradiated while rotating the rotary table 7. The outer periphery was cut.

The center hole of the digital disk cut out from the substrate 1 in this manner had a maximum roundness of 4 μm or less, and a maximum concentricity of 6 μm between the center hole and the pit row, both of which satisfied current standards. Furthermore, the cut-out digital discs could be perfectly played even on the simplest commercially available CD player.

In addition, in the same method as in the example, the substrate may be fixed and the microscope rotated, and in that case, the inner and outer periphery of the elongated plate-shaped substrate shown in FIG. 2 can be cut. .

〔Effect of the invention〕

According to the present invention, the center point of the vortex of the pit row is determined by using the pit row already formed as digital information on the substrate, and the center hole and the outer periphery located at a predetermined distance from this center point are laser-diagnosed. Since the disc is cut with a treadmill, a digital disk can be cut out from a substrate on which digital information has been written in advance by simply and precisely cutting the center hole and the outer periphery in a non-contact state.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of a device used to cut out a digital disk from a substrate in an embodiment of the present invention, and FIG. 2 is a plan view showing an example of a substrate on which a spiral pit row is formed. . DESCRIPTION OF SYMBOLS 1... Substrate, 2... Pit row, 3... Innermost pit row, 4... Outermost pit row, 5... Digital information recording area, 6... Reflective film, 7... Turntable, 8... Drive motor, 9... Drive belt , 10... Microscope, 11... Laser light source, 12a, 12b... Laser light.

Claims (1)

[Claims] 1 Detect the pit row of the board on which digital information is recorded using a spiral pit row, find the center point of the vortex of the pit row from the detected pit row, and move the board around the found center point of the vortex of the pit row. By rotating at least one of the laser beams and irradiating the laser beam to at least one of the inside of the innermost pit row and the outside of the outermost pit row of the digital information recording area consisting of pit rows, the center of the digital disk is A laser cutting method for digital disks in which at least one of the holes and the outer periphery is cut concentrically from the substrate into pit rows.