KR100235997B1 - Optical and a method for prohibiting copy of its disc - Google Patents

Abstract

An optical disc and an optical disc copy protection method for preventing illegal copying of information recorded on an optical disc by recording additional information by changing reflectance in a specific area of the optical disc, and particularly, a lead-in area from the inside of the lead-in area. Part of the data recorded by the pit on the disc is recorded by varying the reflectance using a high power laser in a specific area up to a part of the beginning of the information, and information recorded by the pit and information of the specific area recorded by the high power laser during reproduction In this case, the data or TOC information of the completed program area is transmitted by the combination of the two and the illegal copying of the disc. Therefore, the information of the specific area and the pit information are different from each other so that the information of the specific area is not copied. If you play the copied disc, the data recorded at high output will be lost. Life is not achieved.

Description

Optical discs and optical disc copy protection methods

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disc recording and reproducing method, and more particularly to an optical disc and an optical disc copy protection method for preventing illegal copying of information recorded on an optical disc by recording additional information by changing reflectance in a specific area of the optical disc. It is about.

Conventionally, there has been a method of scrambling data and writing to an optical disk.

Therefore, during playback, if an encryption key is input, the scrambled data is descrambled according to the encryption key and played back normally.

However, this was intended to restrict viewing of minors or paid programs and not to prevent illegal copying.

In other words, even if the disk is illegally copied, if the encryption key is known, normal playback is possible and illegal copying cannot be prevented.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to change the reflectance so that an area for recording information is set from the inside of the lead-in to the beginning of the lead-in area, so There is provided an optical disk which allows a part to be recorded by changing reflectance.

Another object of the present invention is to record additional information by varying the reflectance in a specific area of the optical disc, and to read the information by detecting the envelope of the reproduction signal read out from the optical pickup, so that the additional information of the specific area is used for illegal copying. The present invention provides a disc copy protection method that prevents illegal copying of information recorded on an optical disc by copying only the pit information instead of the copy.

An optical disk according to the present invention for achieving the above object is characterized in that the data area in which data is recorded in the form of pits comprises a lead-in area, a program area, and a lead-out area. From the inside of the to the part of the beginning portion of the lead-in area is set to the additional information area, and the additional information is recorded in the additional information area by changing the reflectance with a high power laser.

A feature of the optical disk copy protection method according to the present invention is that, unlike the lead-in area, program area, and lead-out area of the optical disk in which data is recorded in the form of pits, the reflectance is changed by a high-power laser to a specific area of the optical disk. The additional information is recorded so that data of a specific area is not copied when the disk is copied, thereby preventing the disk from being copied.

1 is a cross-sectional view showing the structure of an optical disk according to the present invention

FIG. 2 is a diagram illustrating a recording pattern of an additional information area of FIG. 1. FIG.

FIG. 3 is a diagram illustrating an information recording form of an additional information area of FIG. 1. FIG.

4 shows an example of a signal reproduced on an optical disc according to the present invention;

FIG. 5 is a block diagram illustrating a configuration of an envelope detection circuit that detects envelope information in a reproduction signal of FIG.

Explanation of symbols for the main parts of the drawings

11a: clamping area 11b: lead-in area

11c: Program area 11d: Lead out area

11e: additional information area 51: upper envelope detector

52: lower envelope detector 53: differential amplifier

54: comparator

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view showing the structure of an optical disk according to the present invention, in which the center hole of the disk 11 is drilled with a radius of 7.5 mm to minimize eccentricity at the time of reproduction, and the disk is wound around the center hole. The clamping area 11a for clamping down starts from within 11 mm from the disk center axis and continues to 16.5 mm.

Areas for recording signals on the disc include a lead in area 11b, a program area 11c, and a lead out area 11d.

The lead-in area 11b records information about data continuously recorded within a maximum of 22.6 mm from the disc central axis and immediately before the start position of a program area of 24 mm, that is, TOC (Table Of Contents) information. (11c) starts within 24 mm from the center axis and continues up to the start position of the lead out area of up to 58 mm so that actual data is recorded in the form of Pit, and the lead out area 11d starts within 58 mm from the center axis. A signal indicating the end of the program is recorded continuously up to 60 mm.

Further, starting from the inside of the lead-in area 11b, up to a part of the initial portion of the lead-in area 11b is set as the additional information area 11e.

The inside of the lead-in area 11b where the additional information area 11e starts is a position where the pick-up can reach, that is, a position where the pick-up can move to the innermost and read the recorded information.

In the additional information area 11e, information is recorded using an industrial or medical laser system having a strong output, such as a high output laser, for example, a yag laser, as a post processing of the optical disk.

The form of the information recording is in the form of a strip (Stripe) from the center of the disc to the outside, as shown in Figure 2, so that the row of these bars are arranged in the circumferential direction of the disc.

Then, as shown in Fig. 3, the data recording pattern of the additional information area 11e recorded by the high power laser has a synchronization part for notifying the start of data, a data part for recording actual data, and an error in the recorded data. It consists of an error correction code required to correct the error.

Here, the synchronization unit may use a special bit string that does not appear in the data unit as the synchronization unit data, and the error correction code may be configured by using a Reed-Solomon code widely used in the CD or DVD series.

The synchronization unit, the data unit, and the error correction code are recorded repeatedly as one information frame while making one circumference, that is, one rotation of the disc.

At this time, the data recorded in the data portion is a part of the data recorded in the program area of the disc or the important information of the disc recorded in the lead-in area, that is, a part of the TOC. The information recorded by the high-power laser is omitted in the information recorded in the data portion of the lead-in area or the program area.

At the time of reproduction, it is possible to specify that the data of the completed program area or TOC information is transmitted to the host computer or the like by combining the information of the additional information area 11e recorded by the high power laser and the information read from the pit.

Therefore, when the disc is illegally copied, the data of the additional information area 11e is not copied because the recording method is different from that of the lead-in area or the program area. When the illegally copied disc is reproduced, the data is recorded at high output. No data can be played back, which prevents accurate playback.

That is, it is possible to prevent the possibility of illegal copying at the source.

On the other hand, the information is recorded in the additional information area 11e by irradiating a high power laser to a transparent substrate that protects the recording layer of the disk, thereby influencing the transparency of the substrate and thus, from the optical pickup. The amplitude modulation effect is produced on the envelope of the read-out reproduction signal so that the information can be read by detecting the envelope. The transparent substrate is composed of PMMA or polycarbonate.

Therefore, since the information of the additional information area 11e in which the information is recorded by the high power laser is reduced in transparency, when the information of the additional information area 11e is reproduced, the amplitude of the reproduction signal is as shown in FIG. 4. ) Becomes smaller than the amplitude of the reproduction signal.

Fig. 5 is a block diagram showing the configuration of an envelope detecting circuit according to the present invention for detecting an envelope of a reproduction signal. An upper envelope detector 51 for detecting an upper envelope of a reproduction signal, and a lower envelope detector for detecting a lower envelope of a reproduction signal. (52), the differential amplifier 53 for differentially amplifying the upper and lower envelopes detected by the upper envelope detector 51 and the lower envelope detector 52, and the output of the differential amplifier 53 is compared with a preset reference voltage Comparator 54 for outputting envelope information.

In the present invention configured as described above, when the disc is reproduced, the upper envelope detector 51 detects the upper envelope of the reproduction signal as shown in Fig. 4, and the lower envelope detector 52 detects the lower envelope of the reproduction signal.

The differential amplifier 53 amplifies the difference between the upper envelope signal and the lower envelope signal detected by the upper envelope detector 51 and the lower envelope detector 52, and outputs the amplified difference to the comparator 54, and the comparator 54 outputs the differential. The output of the amplifier 53 is compared with a preset reference voltage to output binarized envelope information.

As described above, according to the optical disk and the optical disk copy protection method according to the present invention, by varying the reflectance using a high-power laser in the specific area from the inside of the lead-in area to the first part of the lead-in area, By copying part of the data recorded in the pit and reproducing, the disc is illegally copied by combining the information of the specific area recorded by the high-power laser and the information recorded in the pit to transmit the data of the completed program area or TOC information. In this case, since the information of the specific area and the pit information are different in the recording method, the information of the specific area is not copied. When the illegally copied disc is reproduced, no data is recorded at high output and accurate reproduction is not performed. Therefore, it is possible to prevent the possibility of illegal copy at source, thereby protecting the copyright of the information recorded on the disc.

Claims (9)

In an optical disc comprising a lead-in area, a program area, and a lead-out area in which data is recorded in the form of pits, And from the inside of the lead-in area to a part of the first part of the lead-in area as an additional information area, and recording the additional information by changing a reflectance with a high power laser in the additional information area. The method of claim 1, wherein the inside of the lead-in area where the additional information area begins An optical disc, wherein the pickup moves to the innermost position to read recorded information. The method of claim 1, wherein the additional information recorded in the additional information area is Table of Contents (TOC) An optical disc characterized as part of the data. The method of claim 1, wherein the additional information recorded in the additional information area is An optical disc, characterized in that it is part of data recorded in a program area. The recording form of the additional information area according to claim 1, wherein An optical disc, characterized in that it is shaped like a rod from the center of the disc to the circumference, with the rows of these bars arranged in the circumferential direction of the disc. Unlike the lead-in area, program area, and lead-out area of the optical disk in which data is recorded in the form of pits, the reflectance is changed by a high-power laser to record additional information in a specific area of the optical disk, so that the specific area when copying the disk An optical disc copy protection method that prevents copying of discs by preventing data from being copied. The method of claim 6, wherein the additional information of the specific area is Table of Contents Table (TOC) An optical disc copy protection method, which is part of the data. The method of claim 6, wherein the additional information of the specific area is An optical disc copy protection method, characterized in that it is part of data recorded in a program area. The method of claim 6, Detects the upper and lower envelope signals in the reproduction signal of the optical disc, amplifies the difference between the upper and lower envelope signals, and outputs binarized envelope information by comparing the preset reference voltage to reproduce additional information of the specific region. Optical disk copy protection method characterized in that.

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