JPH07118103B2 - Optical information recording medium manufacturing method and optical information recording medium master disc exposure apparatus - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing an optical information recording disk master and an exposure apparatus for an optical information recording disk master applied to the implementation of this manufacturing method.

[Conventional technology]

Conventionally, a laser head is transferred at a constant speed in a radial direction of a resist master rotating at a constant angular velocity, the resist master is exposed by a cutting laser beam emitted from the laser head, and the exposed resist master is developed. Therefore, there is known a manufacturing method of an optical information recording disk master in which an optical information recording disk master having a pit row corresponding to a recording signal is obtained.

The required optical information recording disk is duplicated from the disk master prepared as described above. That is, by electroforming nickel or the like on the pit row forming surface of the disk master, first, a stamper having a concavo-convex pattern reverse to that of the disk master is prepared, and then the stamper is used as a master for the 2P method or the intrusion method. An optical information recording disk having the same concavo-convex pattern as that of the disk master is produced by using a transfer technique such as. As described above, since the optical information recording disk is produced from the disk master by using the replication technique, the resist master, which is the basis of the disk master, has a read signal from each pit formed on the optical information recording disk. It is necessary to irradiate the cutting laser beam on the basis of the recording signal such that the pulse width of is equal to a predetermined value.

Conventionally, a resist master is exposed by using a signal to be read from the optical information recording disk as a recording signal source.

[Problems to be solved by the invention]

However, since the cutting laser beam is applied over a certain area on the resist master, for example, as shown in FIG. 5, even if the cutting beam is applied based on the recording signal having the pulse width l, A pit 22 of l + 2r (r is a radius of the beam spot 21) is formed on the master disk, and an error corresponding to the diameter 2r of the beam spot 21 is generated.

When a recording signal is read from the optical information recording disk by the optical information recording / reproducing apparatus, as shown in FIG. 6, the reproducing laser beam 23 is irradiated along the above-mentioned row of pits and the pits are lit.
The presence or absence of 22 is optically determined. However, since the reproducing laser spot 23 has a radius R, for example, the pit 22 formed by the recording signal having the pulse width 1 is There is a problem that it is read as a recording signal having a length of (l + 2r + 2R), and the optical information recording / reproducing apparatus cannot accurately reproduce the read signal with respect to the recording signal of the optical information recording disk. Particularly, in the exposure method in which the resist master is rotated at a constant angular velocity, as shown in FIG. 7, as the irradiation position of the beam spot reaches the inner peripheral portion of the resist master, the exposure length for the recording signal having the same pulse width is increased. Since the length becomes shorter, the effect of the beam spot diameter becomes more significant. In recent years, in this type of optical information recording disk, increasing the recording capacity has become one of the most important technical problems, and the expansion of the recording area in the inner peripheral portion of the disk is being considered. The poor reproducibility in the peripheral portion is also a problem from the viewpoint of expanding the recording area.

In the above description, the reason why the read signal length of the optical information recording / reproducing apparatus does not accurately correspond to the recording signal length is that the diameters of the cutting laser beam of the exposure apparatus and the reproducing laser beam of the optical information recording / reproducing apparatus are different. Although only the effect was explained, in addition to this, for example, unevenness of laser power or unevenness of development processing due to fluctuation of focusing,
In addition, many factors are complicatedly entangled, such as the accuracy of multiple stages of transfer performed from the disc master to the product completion, and the recording signal length to obtain the required read signal length before exposure of the resist master. It is difficult to accurately determine the power by calculation.

[Means for solving problems]

The present invention solves the above-mentioned problems of the prior art, and is for manufacturing an optical information recording disc capable of accurately matching the pulse widths in a recording signal of an exposure device and a reading signal of an optical information recording / reproducing device. The present invention has been made in order to provide a method for manufacturing a master and an exposure apparatus, and prior to exposing a resist master for producing an optical information recording disk, a preliminary recording signal such as a pulse width The difference between the signal read by the optical information recording / reproducing device is obtained in advance by using the optical information recording disc duplicated from the disc master on which the recording signal is written, and the recording is adjusted by this difference. The present invention relates to a method for manufacturing an optical information recording disk, which is characterized in that a resist master is exposed by an exposure device based on a signal. The present invention also provides a recording signal source comprising a pulse width of a recording signal and a pulse width of a signal read by an optical information recording / reproducing apparatus from an optical information recording disc reproduced from a disc master on which the recording signal is written. The feature of the exposure apparatus is that a correction means for correcting the difference is added to the exposure apparatus.

〔Example〕

A method of manufacturing the optical information recording disk master according to the present invention will be described with reference to the flowchart of FIG.

First, evenly apply photoresist to one side of the glass plate,
This is baked to prepare a resist master disk {FIG. 1 (a)}.

Then, the resist master is placed on a turntable, rotated at a constant angular velocity, and the laser head is moved in the radial direction of the resist master to produce the same pulse as the signal to be read from the optical information recording disk. A laser beam modulated by a recording signal having a width is emitted.
{(FIG. 1 (b)}.

Then, by developing the exposed resist master, a disk master having a pit row is produced {(FIG. 1 (c)}.

Then, a stamper is copied from the disk master, and further, an optical information recording disk having the same concavo-convex pattern as the disk master is copied from the stamper {(first
Figure (d)}.

Next, the recording signal is read from the optical information recording disk, and the pulse width of the recording signal with respect to the distance from the rotation center of the optical information recording disk to the irradiation position of the reproducing laser beam and the disk in which the recording signal is written. The difference from the pulse width of the signal read from the optical information recording disk reproduced from the master is determined {Fig. 1 (e)}.

Next, another resist master manufactured in exactly the same manner as the resist master is placed on the turntable and rotated at a constant angular velocity, and the laser head is transferred in the radial direction of the resist master, as described above. The laser beam modulated by the recording signal in which the difference calculated in the above is corrected is irradiated {FIG. 1 (f)}.

After that, the required optical information recording disk is duplicated through the same steps as in FIGS. 1 (c) and 1 (d) {FIG. 1 (g)}.

According to the manufacturing method of the above optical information recording disk master,
Since the laser beam modulated by the recording signal in which the difference between the signal and the read signal is corrected is applied to the resist master disc, the optical disc for recording optical information copied from the resist master disc is used for recording. A read signal equal to the signal can be read.

Hereinafter, a specific device for carrying out the above-described method for manufacturing the optical disk for recording optical information will be described.

FIG. 2 is an optical circuit diagram showing an optical system of the exposure apparatus according to the present invention, which mainly comprises a laser generator 1, an objective lens 2, a laser optical path 3, an optical modulator 4, and a recording signal source 5. A recording signal correction device 6 and a turntable 8 for rotationally driving the resist master 7.

Of the above devices, a laser generator 1, an objective lens 2,
The laser optical path 3, the optical modulator 4, the recording signal source 5, the resist master 7, and the turntable 8 are exactly the same as the conventionally known exposure apparatus, and the feature of the present invention is that the conventionally known exposure apparatus. The recording signal correction device 6 is added to the recording signal source 5 of FIG.

FIG. 3 is a circuit diagram showing an example of the recording signal correction device 6, which is composed of a ROM circuit 9, a delay circuit 10, an inverter 11, and an AND circuit 12. The ROM circuit 9 has a pulse width of a recording signal with respect to the distance from the rotation center of the resist master 7 to the irradiation position of the cutting laser beam, and an optical information recording reproduced from the disk master in which the recording signal is written. Data for correcting the difference with the pulse width of the signal read from the disk is stored in advance. In FIG. 3, reference numeral 13 is distance information from the rotation center of the resist master 7 provided to the ROM circuit 9 to the irradiation position of the cutting laser beam, and 14 is the ROM circuit 9.
Delay information output from the delay circuit 10 to the delay circuit 10
16 is a recording signal input to the delay circuit 10 and the AND circuit 12, and 17 is a corrected recording signal output from the AND circuit 12.

The recording signal correction device 6 operates as shown in FIG.

That is, the recording signal source 5 outputs the recording signal 16 {FIG. 4 (a)} to be read from the optical information recording disk duplicated from the resist master 7 as in the conventional case.

On the other hand, the ROM circuit 9 outputs the optimum delay information 14 for the distance information 13 based on the distance information 13, and as a result, the delay circuit 10 outputs the delay signal 15 (fourth delay signal) corresponding to the delay information 14.
Figure (b)} is output.

In the AND circuit 12, the recording signal 16 and the delay signal 15 are ANDed, and the recording signal 17 corrected so that the read signal length from each pit formed on the optical information recording disk becomes a predetermined value. {Fig. 4 (c) is output.

Incidentally, the gist of the present invention is that the recording signal length with respect to the distance from the rotation center of the resist master to the irradiation position of the cutting laser beam and the read signal length from the optical information recording disk produced from the disk master. Since the correction means for correcting the deviation is added, the recording signal correction device is not limited to the above device, and other means such as a CPU can be used.

〔The invention's effect〕

As described above, in the method for manufacturing the optical information recording disc master of the present invention, the resist master is irradiated with the laser beam modulated by the recording signal whose difference from the read signal is corrected. A read signal equal to a recording signal can be read from the optical information recording disk duplicated from the resist master. Therefore, the information reproducibility of the optical information recording disk is improved and the recording area can be expanded.

[Brief description of drawings]

FIG. 1 is a flow chart showing an example of a method for manufacturing an optical information recording disc master according to the present invention, and FIG. 2 is an optical circuit diagram showing an optical system of an optical information recording disc master exposing apparatus according to the present invention. FIG. 1 is a circuit diagram showing an example of a recording signal correction device,
FIG. 4 is a graph showing the operation of the recording signal correction device, FIG. 5 is a plan view showing a pit formed by a conventional method for manufacturing a disc master for optical information recording, and FIG. 6 is a conventional optical information recording. FIG. 7 is a plan view showing a signal read-out means of a recording disk, and FIG. 1: laser generator, 2: objective lens, 3: laser optical path, 4: optical modulator, 5: recording signal source, 6: recording signal correction device, 7: resist master, 8: turntable, 9: ROM circuit, 10: delay circuit,
11: Inverter 11, 12: AND circuit, 13: Distance information, 14: Delay information, 15: Delay signal, 16: Recording signal, 17: Corrected recording signal

Claims (2)

[Claims] 1. A laser head is moved in a radial direction of a rotating resist master, and the master is exposed by an exposure device that exposes the resist master with a cutting laser beam emitted from the laser head, and the exposed resist master is exposed. Is produced to produce an optical information recording disc master for forming a pit row corresponding to a recording signal, and a method for producing an optical information recording disc on the basis of the optical information recording disc master. The difference between the reproduction signal read by the information recording / reproducing device from the optical information recording disc duplicated from the disc master on which the recording signal is written and the recording signal of the exposure device is obtained in advance,
A method for manufacturing an optical information recording disk, characterized in that the resist master is subjected to cutting exposure based on the recording signal adjusted by the difference. 2. A laser generator, an objective lens, an optical modulator arranged in a laser optical path from the laser generator to the objective lens, and a recording signal source for supplying a recording signal to the optical modulator. In an exposure apparatus for an optical information recording disc master provided with a rotationally driven resist master, from the optical information recording disc duplicated from the recording signal and the disc master on which the recording signal is written, in the recording signal source. An exposure apparatus for an optical information recording disk master, further comprising a correction means for correcting a difference from a reproduction signal read by the information recording / reproducing apparatus.