HK1082100A - High-density reproduction-only optical disc and method of recording and/or reproducing data on the same - Google Patents

Description

High-density reproduction-only optical disc and method of recording and/or reproducing data thereon

Technical Field

The present invention relates to a high-density reproduction-only optical disc in which reproduction-only data is formed of groove wobbles (groove wobbles) and user data is formed of pits (pits) and reproduced through a channel different from the reproduction-only data, and a method of recording and/or reproducing data on the disc.

Background

In general, an optical disc is an information recording medium used with an optical pickup apparatus that records/reproduces information in a non-contact manner with respect to the optical disc, the optical pickup apparatus. Optical discs are generally classified as Compact Discs (CDs) or Digital Versatile Discs (DVDs) according to their storage capacity. Examples of several types of optical discs capable of recording, erasing, and/or reproducing information include: 650MB may record CD (CD-R), CD-RW-rewritable (CD-RW), 4.7GB DVD + RW, DVD plus random access memory (DVD + RAM), and DVD-RW. 650MBCD and 4.7GB DVD-ROM are examples of reproduction-only optical discs. In addition, a high-density optical disc (such as an HD-DVD) having a recording capacity of 20GB or more has been developed.

Generally, disc-related information (i.e., reproduction-only data) is recorded as pits positioned in a lead-in area of an inner portion of a conventional reproduction-only optical disc. However, in order to design a reproduction-only optical disc compatible with the same optical disc drive as will be used with the high-density recordable optical disc to be developed, the format of the optical disc must be consistent. Therefore, the physical data structure of the high-density reproduction-only optical disc must conform to the same standard as the high-density recordable optical disc.

Disclosure of Invention

The present invention provides a high-density reproduction-only optical disc having an improved physical data structure having good reproduction signal characteristics, good jitter characteristics, and conforming to the format of a high-density recordable optical disc, and a method of recording or reproducing data on the high-density reproduction-only optical disc.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

According to an aspect of the present invention, a high-density reproduction-only optical disc includes: a lead-in area, a user data area, and a lead-out area, wherein disc-related information is recorded as a high frequency groove wobble on at least one of the lead-in area and the lead-out area, and data is recorded as pits in the user data area.

According to other aspects of the present invention, a depth of the groove wobble is substantially the same as a depth of the pits, or substantially different from the depth of the pits.

According to a further aspect of the present invention, when n represents a refractive index of the disc and λ represents a wavelength of a reproducing beam, a depth of the pit ranges from λ/12n to λ/2n and a depth of the groove wobble ranges from λ/20n to λ/5 n.

According to a further aspect of the present invention, the groove wobble is reproduced through a differential signal channel, and the pits are reproduced through a sum signal channel.

According to another aspect of the present invention, a method of recording data on or reproducing data from a high-density reproduction-only optical disc having a lead-in area, a user data area, and a lead-out area, includes: recording disc-related information as a high-frequency groove wobble in at least one of the lead-in area and the lead-out area; and recording data as pits on the user data area.

Drawings

The above and/or other aspects and advantages of the present invention will become more apparent by describing in detail embodiments thereof with reference to the attached drawings in which:

fig. 1A to 1C schematically show the structure of a high-density recordable optical disc related to the present invention;

fig. 2A to 2C schematically show the structure of a high-density reproduction-only optical disc according to an aspect of the present invention;

fig. 3 is a graph showing a variation in a push-pull signal and a jitter characteristic according to a groove depth;

fig. 4A to 4E are diagrams illustrating a process of manufacturing a high-density reproduction-only optical disc according to an aspect of the present invention;

FIGS. 5 and 6 are perspective views of a portion of a high-density reproduction-only optical disc according to aspects of the present invention;

fig. 7 is a diagram schematically showing a system for reproducing data from a high-density reproduction-only optical disc according to an aspect of the present invention; and

fig. 8 is a perspective view of a portion of a high-density reproduction-only optical disc according to an aspect of the present invention.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures.

The physical structure of a high-density recordable optical disc usable according to an aspect of the present invention is shown in fig. 1. The high-density recordable optical disc uses a format disclosed by this application in korean patent application No. 2001-23747 and us patent application No. 10/128,530 (U.S. patent publication No. 2003-0002427a 1), the disclosures of which are incorporated herein by reference. The high-density recordable optical disc includes: a lead-in area 110, a user data area 120, and a lead-out area 130. The disc has groove tracks 123 and land tracks 125. Here, the user data may be recorded on only the groove track 123, or on both the groove track 123 and the land track 125.

When reproduction-only data is recorded, wobble signals 105 and 106 having a wave with a specific frequency are successively recorded on the sidewall of each of the groove tracks 123 and/or the land tracks 125, not on pits. Here, data is recorded or reproduced by the laser beam L traveling along the groove tracks 123 and/or the land tracks 125. In particular, the lead-in area 110 and the lead-out area 130 include a reproduction-only area and a recordable area for recording disc-related information, respectively. The disc-related information is recorded by the high frequency wobble signal 105. In addition, in the recordable areas of the lead-in area 110 and the lead-out area 130 and in the user data area 120, data is recorded by the wobble signal 106 having a lower frequency than the high frequency wobble signal 105. Recording marks 127 are formed in the user data area 120.

The high frequency wobble data is reproduced through a differential signal channel ch2 (refer to fig. 7) using a push-pull signal, and the data formed in the user data area 120 is reproduced through a sum signal channel ch1 (refer to fig. 7).

The physical data structure of the high-density reproduction-only optical disc according to the present invention is designed in consideration of the format of the high-density recordable optical disc as described above. Referring to fig. 2A to 2C, the high-density reproduction-only optical disc according to the present invention includes: a lead-in area 10, a user data area 13, and a lead-out area 15. Reproduction-only data such as disc-related information is recorded on at least one of the lead-in area 10 and the lead-out area 15. Reproduction-only user data is recorded on the user data area 13. Groove tracks 3 and land tracks 5 are alternately formed in the lead-in area 10 and the lead-out area 15. Reproduction-only data such as disc-related information is recorded by the high-frequency groove wobbles 8 formed as waves on the side walls of each of the groove tracks 3 and/or the land tracks 5. In addition, user data is recorded in the form of pits 18 when the disc is manufactured. The disc shown in fig. 2A to 2C is a hybrid disc and has different reproduction channels for reproduction-only data and user data.

Fig. 3 shows a push-pull signal and jitter characteristics according to the depth of a groove wobble or the depth of a pit. The depth of the groove wobbles or pits is determined so that the push-pull signal or jitter characteristics are good. Here, the jitter characteristic is related to the sum signal. That is, the smaller the jitter value, the better the sum signal. When n represents the refractive index of the disc and λ represents the wavelength of the reproduction beam, the push-pull signal as shown in fig. 3 indicates the maximum value at the depth of λ/8n, and the jitter value indicates the minimum value at the depth of λ/4 n. Therefore, the reproduced signal has a maximum pit depth of λ/4 n. In the graph of fig. 3, the depth of the groove wobbles or pits is in units of wavelength (λ/n).

The groove wobbles 8 having the same depth as the pits 18 can be formed in the high-density reproduction-only optical disc according to an embodiment of the present invention. The depth of the groove wobbles 8 or the pits 18 may be determined in consideration of a push-pull signal of the groove wobbles 8 and a jitter value of the pits 18 with reference to the graph of fig. 3. For example, although the push-pull signal and the jitter value are slightly lower than their maximum values when the groove wobbles 8 and the pits 18 are the same depth, the depths of the groove wobbles 8 and the pits 18 may be determined to obtain reliable reproduction signals of the push-pull signal and the jitter value. For example, in the case where the groove wobbles 8 and the depths of the pits 18 are set to λ/6n, the push-pull signal is reduced by about 12% compared to the maximum value thereof, and the jitter value of the pit signal is increased by about 0.4% compared to the minimum value thereof. However, when not ideal, a reliable reproduction signal of the push-pull signal and the jitter value can be obtained from the above values. In the case where the depths of the groove wobbles 8 and the pits 18 are the same as described in the above embodiments, the process of manufacturing the optical disc is significantly simplified.

In addition, according to another embodiment, the depth of the groove wobbles 8 or the pits 18 may be set to an optimum value for only one of the push-pull signal and the jitter value. That is, the depth of the groove wobbles 8 or the pits 18 may be set to an optimum value only for a push-pull signal, for example, λ/8n, or may be set to an optimum value only for a jitter value, for example, λ/4 n.

In addition, according to another embodiment, the depth of the groove wobbles 8 may be different from the depth of the pits 18. Here, the depth of the pits 18 ranges from λ/12n to λ/2n and the depth of the groove wobbles 8 ranges from λ/20n to λ/5 n. Preferably, the depth of the groove wobbles 8 is set to an optimum value for the push-pull signal, e.g., λ/8n, and the depth of the pits 18 is set to an optimum value for the jitter value, e.g., λ/4 n. Here, λ/8n and λ/4n are just examples of the optimum depth, and the actual optimum depths of the groove wobbles 8 and the pits 18 may vary. Accordingly, in the case where the depth of the groove wobbles 8 is different from the depth of the pits 18, the depths of the groove wobbles 8 and the pits 18 may be determined so that each of the signals corresponding to the groove wobbles 8 and the pits 18 has an optimum value.

An optical disc according to an embodiment of the present invention may be a single layer optical disc or a multi-layer optical disc having multiple information surfaces.

A method for manufacturing an optical disc according to an embodiment of the present invention in which the depth of the groove wobbles 8 is different from the depth of the pits 18 will be described with reference to fig. 4A to 4E. As shown in fig. 4A, the photoresist 20 having the same depth d2 as the pit 18 is uniformly applied on the main glass 18. Thereafter, the photoresist 20 is cut by the laser beam. Land region 25 is cut to depth d1 using laser beam 23 having power Pw 1. Pit areas 28 are cut to a depth d2 using laser beam 26 with power Pw 2. Power Pw2 is greater than power Pw 1. Since the present invention has an even number of stampers and the substrate is embossed using an even number of stampers (such as a second stamper or a fourth stamper), the track is formed in a spiral line that spirals in a direction opposite to a direction in which the disc rotates during reproduction during first laser cutting of the photoresist 20.

As shown in fig. 4B, the laser-cut photoresist 20 is developed to form a master 30 in which the depth d2 of the pit areas 28 is greater than the depth d1 of the land areas 25. As shown in fig. 4C, the father stamper 33 is stamped using the master 30. The shape of the father stamper 33 is opposite to that of the original 30 so that land areas 25 ' are protruded, groove areas 27 between the protruded land areas 25 ' of the father stamper 33 are formed, and pit areas 28 ' are protruded.

Next, as shown in fig. 4D, a mother stamper 35 having an inverse shape of the parent stamper 33 is imprinted using the parent stamper 33. The mother stamper 35 has land areas 25 ", pit areas 28", and groove areas 27 ' opposite in shape to the land areas 25 ', pit areas 28 ', and groove areas 27, respectively, of the mother stamper 33. In order to mold a plurality of substrates using a stamper, a plurality of stampers are required. For this reason, when a plurality of stampers are manufactured using the master 30 having the photoresist 20 as described above, the master 30 is easily worn by the photoresist 20, so that the shape of the stamper manufactured using the master 30 is not good. Therefore, a plurality of mother stampers 35 are stamped using the parent stampers 33 in the present invention, and a plurality of substrates 40 are injection-molded using the mother stampers 35 as shown in fig. 4D.

As described above, if the substrate 40 shown in fig. 5 is manufactured using the father stamper 33 and the mother stamper 35, the shape of the manufactured substrate 40 is the same as that of the father stamper 33, and the shape of the mother stamper 35 is the same as that of the original plate 30. That is, the shape of the master 30 is opposite to the shape of the manufactured substrate 40. Therefore, when a disc is produced using the master stamper 35, if a track is not formed in a spiral line that spirals in the opposite direction during the first laser cutting of the photoresist 20 as shown in fig. 4A, the spiral direction of the track formed in the substrate 40 is opposite to the direction in which the disc must rotate.

Finally, the substrate 40 is molded using the master stamper 35. Here, assuming that the depth of the groove 3 or the groove wobble 8 formed on the substrate 40 is represented by d1 and the depth of the pit 18 is represented by d2 from the incident direction of the reproduction beam, a disc manufactured as d1 < d2 is shown in fig. 5.

In addition, a disc as shown in fig. 6, in which the groove wobbles 8 are deeper than the pits 18 (i.e., d1 > d2), may be manufactured according to another embodiment of the present invention by controlling the powers Pw1 and Pw2 of the laser beam. Further, a disc as shown in fig. 8, in which the groove wobbles 8 and the pits 18 have substantially the same depth (i.e., d 1-d 2), may be manufactured according to another embodiment of the present invention by controlling the powers Pw1 and Pw2 of the laser beam.

A method for recording data on or reproducing data from a high-density reproduction-only optical disc according to an embodiment of the present invention is as follows. The disc-related information is recorded by the high frequency groove wobble 8 on at least one of the lead-in area 10 and the lead-out area 15 shown in fig. 2A to 2C. Data formed in the user data area 13 is recorded in the form of pits 18. Then, the data recorded by the groove wobble 8 is reproduced through a differential signal channel ch2 using a push-pull signal, and the data recorded in the form of pits 18 is reproduced through a sum signal channel ch 1.

As described above, the groove wobbles 8 and the pits 18 may have the same depth, or may have different optimal depths.

Fig. 7 schematically shows an embodiment of a system for recording data on or reproducing data from a high-density reproduction-only optical disc according to the present invention. The system comprises: a pickup unit 45, a recorded/reproduced signal processing unit 60, and a control unit 70. More specifically, the recording/reproducing system further includes: a laser diode 41 for emitting a laser beam; a collimator lens 42 for changing the laser beam emitted from the laser diode 41 into a parallel laser beam; a beam splitter 44 for changing the advancing path of the incident light; and an objective lens 46 for focusing the laser beam passing through the beam splitter 44 on the disc 53.

The laser beam reflected from the disc 53 is reflected by the beam splitter 44 and then received by the photodetector 55. An example of the photodetector 55 is a gradient photodetector 55 that divides an incident laser beam into four beam regions. The laser beam received by the photodetector 55 is converted into an electric signal via the arithmetic circuit unit 50, and then output to the sum signal path ch1 for detecting an RF signal (i.e., sum signal). The differential signal is output to the channel ch2 for detecting the wobble signal using the push-pull method. Pit data of the optical disc according to the present invention is reproduced through the sum signal channel ch1 and groove wobble data is reproduced through the differential signal channel ch 2. In addition, the tracking servo 65 of the control unit 70 may be realized using a signal reproduced through the differential signal path ch 2.

Industrial applicability

As described above, since the high-density reproduction-only optical disc according to the present invention has a physical data structure designed in consideration of the format of the high-density recordable optical disc and channels for reproducing signals are the same in the optical disc, the optical disc is compatible with the same disc drive.

While the present invention has been particularly shown and described with reference to embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents.

Claims (32)

1. A high-density reproduction-only optical disc, comprising:

an introduction zone;

a user data area;

a lead-out area;

disc related information recorded by a high frequency groove wobble on at least one of the lead-in area and the lead-out area; and

data, recorded by pits in the user data area.

2. The high-density reproduction-only optical disc of claim 1, wherein a depth of the groove wobbles is substantially the same as a depth of the pits.

3. The high-density reproduction-only optical disc of claim 1, wherein a depth of the groove wobbles is substantially different from a depth of the pits.

4. The high-density reproduction-only optical disc of claim 3, wherein:

n represents the refractive index of the disk, and

lambda represents the wavelength of a reproducing beam that can be used to reproduce disc-related information and data,

the pits have a depth of λ/12n or λ/2n, or between them, and

the depth of the groove wobbles is λ/20n or λ/5n, or therebetween.

5. The high-density reproduction-only optical disc of claim 4, further comprising an information surface including one or more layers, each layer having data of a corresponding lead-in area, user data area, lead-out area, disc-related information, and user data area.

6. The high-density reproduction-only optical disc of claim 4, wherein:

the groove wobble is optimized to be reproduced through a differential signal path, an

The pits are optimized to be reproduced through the sum signal channel.

7. The high-density reproduction-only optical disc of claim 1, further comprising an information surface including one or more layers, each layer having data of a corresponding lead-in area, user data area, lead-out area, disc-related information, and user data area.

8. The high-density reproduction-only optical disc of claim 1, wherein:

the groove wobble is optimized to be reproduced through a differential signal path, an

The pits are optimized to be reproduced through the sum signal channel.

9. A method of recording data on a high-density reproduction-only optical disc having a lead-in area, a user data area, and a lead-out area, the method comprising:

recording disc-related information using a high frequency groove wobble on at least one of the lead-in area and the lead-out area; and

data is recorded using pits on the user data area.

10. The method of claim 9, wherein a depth of the groove wobble is substantially the same as a depth of the pits.

11. The method of claim 9, wherein a depth of the groove wobbles is substantially different from a depth of the pits.

12. The method of claim 11, wherein:

n represents the refractive index of the disk, and

λ represents a wavelength of a reproducing beam usable for reproducing the disc-related information and data;

the pits have a depth of λ/12n or λ/2n, or between them, and

the depth of the groove wobbles is λ/20n or λ/5n, or therebetween.

13. The method of claim 9, wherein the high-density reproduction-only optical disc further comprises an information surface including one or more layers, each layer having data of a corresponding lead-in area, user data area, lead-out area, disc-related information, and user data area.

14. The method of claim 9, wherein:

the groove wobble is optimized to be reproduced through a differential signal path, an

The pits are optimized to be reproduced through the sum signal channel.

15. The high-density reproduction-only optical disc of claim 1, wherein one of the disc-related information and data is recorded on the optical disc using a stamper.

16. The high-density reproduction-only optical disc of claim 15, wherein the optical disc has a recording capacity of 20 gigabytes or more.

17. The high-density reproduction-only optical disc of claim 15, wherein the high-frequency wobbles and the pits are readable by the same optical disc drive that records and/or reproduces a recordable optical disc having a recording capacity of 20 gigabytes or more.

18. The high-density reproduction-only optical disc of claim 17, wherein the optical disc has a recording capacity of 20 gigabytes or more.

19. The method of claim 9, wherein one of recording the disc-related information and recording the data comprises recording using a stamper.

20. The method of claim 19, wherein the optical disc has a recording capacity of 20 gigabytes or more.

21. The method of claim 19, wherein the high frequency wobbles and the pits are readable by the same optical disc drive that records and/or reproduces a recordable optical disc having a recording capacity of 20 gigabytes or more.

22. The method of claim 21, wherein the optical disc has a recording capacity of 20 gigabytes or more.

23. A high-density optical disc comprising:

an introduction zone;

a user data area; and

a lead-out area, wherein the lead-out area is provided with a plurality of lead-out areas,

wherein:

disc related information is recorded as a high frequency groove wobble on at least one of the lead-in area and the lead-out area,

data of the user data area is recorded as pits, an

The capacity of the optical disc is 20 gigabytes or more than 20 gigabytes.

24. The high-density optical disc of claim 23, wherein:

the optical disc is one of recordable and reproduction-only; and

the format of the optical disc is sufficiently the same as the other of the recordable and reproduction-only disc to allow recording and/or reproduction in the same disc drive.

25. The high-density optical disc of claim 23, wherein a depth of the groove wobbles is substantially the same as a depth of the pits.

26. The high-density optical disc of claim 23, wherein a depth of the groove wobbles is substantially different from a depth of the pits.

27. The high-density disc of claim 26, wherein when n represents a refractive index of the disc and λ represents a wavelength of the reproduction beam, a depth of the pits ranges from λ/12n to λ/2n and a depth of the groove wobbles ranges from λ/20n to λ/5 n.

28. A recording and/or reproducing apparatus for use with recordable and reproduction-only optical discs having a common format for indicating disc-related information and data, the apparatus comprising:

a pickup unit for recording and/or reproducing data with respect to one of the loaded recordable and reproduction-only optical discs;

a signal processing unit for processing the signal received from the pickup unit; and

a controller for controlling the signal processor and the pickup unit to record and/or reproduce data with respect to the loaded optical disc,

wherein:

the device is compatible with both recordable and reproduction-only optical discs,

each of the recordable and reproduction-only optical discs includes a lead-in area, a user data area, and a lead-out area, and

disc related information is recorded as a high frequency groove wobble on at least one of the lead-in area and the lead-out area,

data is recorded as pits in the user data area, and

the capacity of recordable and reproduction-only optical discs is 20 gigabytes or more.

29. The recording and/or reproducing apparatus of claim 28, wherein the reproduction-only disc is manufactured using a stamper and has a format sufficiently identical to that of another recordable optical disc to allow recording and/or reproduction in the same disc drive.

30. The recording and/or reproducing apparatus of claim 28, wherein:

the pickup unit includes a light source having a certain wavelength, an

The depth of the groove wobbles is substantially the same as the depth of the pits and is optimized according to the wavelength of the pickup unit.

31. The recording and/or reproducing apparatus of claim 28, wherein:

the pickup unit includes a light source emitting a light beam having a certain wavelength,

the loaded optical disc is a reproduction-only optical disc having a depth of the groove wobbles substantially different from a depth of the pits,

the depth of the groove is optimized with respect to the wavelength to maximize the push-pull signal processed by the signal processing unit, an

The depth of the pits is optimized with respect to the wavelength to minimize jitter.

32. The recording and/or reproducing apparatus of claim 31, wherein,

n represents the refractive index of the disc,

λ represents the wavelength of the light beam,

the depth of the pits ranges from λ/12n to λ/2n, and

the depth of the groove wobble ranges from λ/20n to λ/5 n.