JP2002342935A - Method and device for recording information to optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form an exact bar code shape even though a warpage or undulation exists on an optical disk in recording information to the optical disk by utilizing the bar code. SOLUTION: The working point of an optical disk 1 is arranged along the rotating direction of the optical disk 1 so as to be irradiated with laser beams for working on the same circumference after passing through a height measuring sensor 5, and the angle information at the moment of the measurement and the height information in the Z-direction are stored together. By controlling the position in the Z-direction on the basis of the information in the Z-direction of a rotary table elevating/lowering mechanism 4 stored θ deg. before the present angle position and the measurement value of the height measuring sensor 5, the exact bar code shape is formed on the optical disk even though the warpage or undulation exists on the optical disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recording information on an optical disk, and more particularly, to a method for accurately recording individual information on an individual optical disk.

[0002]

2. Description of the Related Art An optical disk such as a DVD is manufactured by transferring a pit pattern from a metal master or the like on which a pit pattern is formed in advance to a synthetic resin substrate. In this case, an optical disc on which exactly the same information is recorded is manufactured from one master.

On the other hand, there is a case where it is required to assign a serial number (serial number) or an identification code (ID) to each optical disk in order to manage the production and storage of the optical disk or the distribution and sale.

Accordingly, a technique has been proposed in which a bar code is written on a manufactured optical disk with a laser beam to add additional individual information such as the serial number and the identification code described above for each optical disk. In detail, the recording layer inside the optical disk is irradiated with laser light to melt and remove the metal thin film constituting the recording layer in a barcode pattern, thereby producing a difference in reflection characteristics between the removed portion and the surrounding recording layer. . The added information can be read out by applying a simple circuit to a device for reproducing a normal recorded signal, and as a result, by using the above-described serial number and identification code, customer management can be performed. And unauthorized duplication can be reliably and efficiently performed.

In a laser processing apparatus for forming a bar code pattern on an optical disk of this type, the optical disk 1 is placed on a rotary table 2 and rotated as shown in FIG. By irradiating the optical disc 1 with a laser beam, an arbitrary bar code pattern is formed on the optical disc 1. Further, in order to make the shape of the formed barcode pattern accurate, it is necessary to make the focal position of the laser beam uniform, and the rotary table up-and-down mechanism 4 is used to measure the height of the optical disc 1 at high speed. A configuration is adopted in which a height measurement sensor 5 using laser light is arranged, and the rotary table up-down mechanism 4 is controlled so that the measurement value obtained from the height measurement sensor 5 becomes constant.

[0006]

An actual processing disk has warpage or undulation. In order to form an accurate bar code pattern in the above-described configuration, the processing laser is rotated while rotating the disk. It is necessary to perform auto-focus control so that the height of the processing point where light is irradiated becomes constant. However, as shown in FIG. 1, the height measuring sensor 5 is arranged so that the optical axis of the height measuring sensor 5 passes coaxially with the processing optical axis.
Is arranged, the measurement value of the height measurement sensor 5 becomes unstable due to, for example, a decrease in the reflectance of the input light of the height measurement sensor 5 due to the influence of the irradiation laser for processing, and the disc height information is correctly obtained. Measurement may not be possible.

If the optical axis of the height measuring sensor 5 is arranged so as not to be affected by the processing laser, a point different from the processing point will be measured, and warpage and undulation on the periphery will be measured. On the other hand, an accurate autofocus operation cannot be performed.

According to the present invention, in recording information using a barcode on an optical disk as described above, the processing point of the optical disk during the processing operation is maintained at a constant height even if the optical disk is warped or undulated. Therefore, an object of the present invention is to form an accurate barcode shape.

[0009]

According to the present invention, a height measuring sensor is arranged on the same circumference as a processing point. The arrangement is such that in the direction of rotation, the processing point of the optical disc can be irradiated with the laser beam for processing after passing through the height measurement sensor.
It is assumed that the position is shifted by an angle θ from the arrangement position of the height measurement sensor. When rotation starts, using height measurement sensor,
The height measurement is started and stored together with the angle information in the rotation direction at the time of measurement and the height information in the Z direction. At the point in time when the rotation of the angle θ has elapsed from the rotation start, when the machining operation is started, at the point before the current angle position by the angle θ,
The vertical position of the optical disk is controlled based on the stored Z-direction information of the vertical mechanism and the measurement value of the height sensor so that the height of the processing point is constant.

By using this configuration and control method, it is possible to keep the height of the processing point of the disk constant, thereby making the focal point of the laser irradiated for processing uniform.
An accurate barcode pattern can be formed on an optical disc.

[0011]

Embodiments of the present invention will be described below.

FIG. 1 shows a schematic configuration of an apparatus for recording information on an optical disk according to an embodiment of the present invention. The optical disk 1 is set on a rotary table 2 on which a rotary encoder 3 is mounted. The height measuring sensor 5 and the barcode writer 6 for irradiating the laser are arranged on the same circumference. The rotary table 2 is moved up and down by a table up / down mechanism 4 to change the distance between the optical disk 1 and the barcode writer 6 and the distance between the optical disk 1 and the height measurement sensor 5. The overall control of these components is controlled by the controller 7. The height measurement sensor 5 and the barcode writer 6 are mounted at a position shifted by an angle θ, so that the height measurement of the optical disk 1 across the height measurement sensor 5 is performed first in the counterclockwise rotation direction of the disk. Shall be

The number of pulses of the rotary encoder 3 is 10000 pulses / r, the mounting angle deviation θ = 36 degrees,
It is assumed that the rotation table 2 is operated at a rotation speed of 1 rps. When the processing is performed over the entire circumference of the optical disc 1, the turntable 2 is rotated by 396 degrees.

As processing in the controller 7,
Assume that the measurement operation of the height measurement sensor 5 and the operation of height adjustment are performed in parallel, and the measurement operation is performed at 1000 points. For this purpose, the pulse value obtained from the rotary encoder 3 is monitored, and the height measuring sensor 5 is used at intervals of 10 pulses.
Measured values H _{1 to} H ₁₀₀₀ , position data Z _{1 to} Z _{1000 of the} table up / down mechanism 4 and values R _{1 to} R of the rotary encoder 3
Save ₁₀₀₀ to internal memory. As a height adjustment operation, a target value of the height sensor is set to T. If it is assumed that the measurement point and the processing point are at the same position, the table up-down mechanism 4 may be operated so that the measurement value of the height measurement sensor 5 always becomes the value of T. The operation of height adjustment is as follows.

As in the measurement operation, the pulse value obtained from the rotary encoder 3 is monitored. Assuming that the value is R, the table up / down mechanism 4 is operated so that the height of the processing point becomes a constant value T by using a pulse value obtained by adding data for the deviation angle θ (= 36 degrees) to R. Let it. That is, since the pulse value for 36 degrees is 1000 pulses,
Comparing the value of (R + 1000) value and R ₁ to R _1000,
(R + 1000) ≦ relationship R _N is satisfied with the first R _N at the same time saved H _N and Z _N of operating a vertical movement mechanism 4. The position of the table up / down mechanism 4 at the time of measurement is Z _N
Since the measurement value of the height measurement sensor 5 is H _N , by moving the table up-down mechanism 4 to a position obtained by adding the difference between H _N and the target value T to Z _N , the height of the processing point becomes The target value T can be maintained.

[0016]

As described above, according to the present invention, by keeping the height of the disk at the processing point constant, an accurate barcode shape can be formed on the optical disk even if the optical disk has warpage or undulation. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an apparatus for recording information on an optical disk of the present invention.

FIG. 2 is a schematic configuration diagram of a conventional information recording apparatus on an optical disk.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical disk 2 Rotary table 3 Rotary encoder 4 Rotary table up-and-down mechanism 5 Height measurement sensor 6 Barcode writer 7 Controller

Claims (1)

[Claims] In an information recording for writing a serial number or an identification code in a bar code form on an optical disk by using a laser beam, a rotation angle of a rotating optical disk and a height of a processing point at the rotation angle are measured. A method for recording information on an optical disk, characterized in that the distance between the laser beam and the optical disk is kept constant by storing the information, and a barcode pattern having a predetermined shape is formed on the optical disk.