A high-density optical disk includes reflective layers respectively formed at both information-recorded surfaces of a first substrate, and semitransparent layers respectively formed at one information-recorded surface of each of second and third substrates. The second and third substrates are respectively bonded at both sides of the first substrate.
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0. 51. An optical disk comprising:
a first substrate having a first information-recorded surface; a second substrate having a second information-recorded surface; and a third substrate having a third information-recording surface.
0. 34. An optical disk comprising:
a first substrate having first and second information-recorded surfaces which are opposite each other; and a second substrate having a third information-recorded surface and formed at a side of said first substrate.
0. 41. An optical disk comprising:
a first substrate; a second substrate having an information-recorded surface and formed at a first side of said first substrate; and a third substrate formed at a second side of said first substrate opposite said first side.
9. An optical disk comprising:
a first substrate having first and second information-recorded surfaces which are opposite each other; a second substrate having a third information-recorded surface; and a third substrate having a fourth information-recorded surface.
0. 49. A method of producing an optical disk, comprising:
producing pits of a first information-recorded surface onto a surface of a first substrate; producing pits of a second information-recorded surface onto a surface of a second substrate; bonding said first and second substrates to opposite sides of a third substrate.
0. 42. A method of producing an optical disk, comprising:
producing pits of an information-recorded surface onto a surface at a first side of a first substrate; and bonding a second substrate at said first side of said first substrate and bonding a third substrate at a second side of said first substrate opposite said first side.
0. 58. A method of producing an optical disk, comprising:
fixing first and second stampers for making pits of respective first and second information-recorded surfaces to a molding machine; and simultaneously forming the pits of the first and second information-recorded surfaces onto first and second surfaces of a first substrate.
0. 44. An optical disk comprising:
a side having first and second information-recorded surfaces to contain data to be reproduced by a light irradiated toward said side; a first substrate having said first information-recorded surface; and a second substrate having said second-information-recorded surface facing said first information-recorded surface.
0. 47. An optical disk comprising:
a first substrate; a second substrate at a first side of said first substrate and having a first information recorded surface facing said first substrate; and a third substrate at a second side of said first substrate opposite said first side and having a second information-recorded surface facing said first substrate.
0. 43. An optical disk comprising:
a first substrate having a first information-recorded surface at a side thereof; and a second substrate having a second information-recorded surface formed at a side of thereof and facing the first information-recorded surface; wherein said first and second-information-recorded surfaces are both in a same half of the optical disk.
1. A high-density optical disk comprising:
reflective layers respectively formed at both information-recorded surfaces of a first substrate; and semitransparent layers respectively formed at one information-recorded surfaces of each of second and third substrates; wherein said second and third substrates are respectively bonded at both sides of said first substrate.
0. 39. An optical disk comprising:
a first substrate having first and second information-recorded surfaces which are opposite each other; a second substrate having a third information-recorded surface and formed at a first side of said first substrate; and a third substrate having a fourth information-recorded surface and formed at a second side of said first substrate opposite said first side.
23. An optical disk comprising:
a first side having first and second information-recorded surfaces to contain first data to be reproduced by a first light irradiated toward said first side; a second side having third and fourth information-recorded surfaces to contain second data to be reproduced by a second light irradiated toward said second side; and a first substrate having said second and third information-recorded surfaces on opposite sides thereof.
0. 37. A method of producing an optical disk, comprising:
fixing first and second stampers for making pits of respective first and second information-recorded surfaces to a molding machine; simultaneously forming the pits of the first and second information-recorded surfaces onto first and second surfaces of a first substrate; producing pits of a third information-recorded surface onto a first surface of a second substrate; and bonding said first substrate with said second substrate.
0. 46. A method of producing an optical disk, comprising:
forming pits of a first information-recorded surface onto a surface of a first substrate; forming a reflective layer on said first information-recorded surface; producing pits of a second information-recorded surface on a surface of a second substrate; and bonding said first substrate to said second substrate so that said first and second-information-recorded surfaces face each other and are on a same half of the optical disk.
0. 45. A method of producing an optical disk, comprising:
forming pits of a first information-recorded surface onto a surface of a first substrate; forming a reflective layer on said first information-recorded surface; producing pits of a second information-recorded surface on a surface of a second substrate; forming a semitransparent layer on said second information-recorded surface; and bonding said semi-transparent layer to said reflective layer using a bonding layer therebetween.
0. 35. An optical disk comprising:
a first side having first and second information-recorded surfaces to contain first data to be reproduced by a first light irradiated toward said first side; a second side having a third information-recorded surface to contain second data to be reproduced by a second light toward said second side; a first substrate having said second and third information-recorded surfaces on opposite sides thereof; and a second substrate having said first information-recorded surface.
0. 54. An optical disk comprising:
a first side having first and second information-recorded surfaces to contain first data to be reproduced by a first light irradiated toward said first side; a second side having a third information-recorded surface to contain second data to be reproduced by a second light toward said second side; and a first substrate having said first information-recorded surface; a second substrate having said second-information-recorded surface; and a third substrate having said third information-recorded surface.
0. 56. An method of producing an optical disk, comprising:
producing pits of a first information-recorded surface onto a surface of a first substrate; producing pits of a second information-recorded surface onto a surface of a second substrate; producing pits of a third information-recorded surface onto a surface of a second substrate; and bonding said second substrate with said first substrate at a first side of said first substrate with said first information-recorded surface and bonding said third substrate to a second side of said first substrate opposite said first side.
0. 36. A method of producing an optical disk, comprising:
forming pits of first and second information-recorded surfaces onto first and second surfaces of a first substrate, respectively; forming first and second reflective layers on said first and second information-recorded surfaces; producing pits of a third information-recorded surface on a first surface of a second substrate; forming a first semitransparent layer on said third information-recorded surface; and bonding said first semi-transparent layer to said first reflective layer using a first bonding layer therebetween.
0. 40. A method of producing an optical disk, comprising:
fixing first and second stampers for making pits of respective first and second information-recorded surfaces to a molding machine; simultaneously forming the pits of the first and second information-recorded surfaces onto first and second surfaces of a first substrate; producing pits of third and fourth information-recorded surfaces onto first surfaces of second and third substrates, respectively; and bonding said second substrate at a first side of said first substrate and bonding said third substrate at a second side of said first substrate opposite to said first side.
0. 48. An optical disk comprising:
a first side having a first information-recorded surface to contain first data to be reproduced by a first light irradiated toward said first side; a second side having a second information-recorded surface to contain second data to be reproduced by a second light toward said second side; a first substrate formed in a middle of the optical disk and extending through to both said first and second sides; a second substrate having said first information-recorded surface which faces said first substrate; and a third substrate having said second information-recorded surface which faces said first substrate.
0. 55. A method of producing an optical disk, comprising:
forming pits of a first information-recorded surface onto a surface of a first substrate; forming a reflective layer on said first information-recorded surface; producing pits of a second information-recorded surface on a surface of a second substrate; forming a first semitransparent layer on said second information-recorded surface; bonding said first semi-transparent layer to said first reflective layer using a first bonding layer therebetween; producing pits of a third information-recorded surface on a surface of a third substrate; and bonding said third substrate to a side of said first substrate opposite to that of said second substrate.
28. A method of producing an optical disk, comprising the steps of:
forming pits of the first and second information-recorded surfaces onto first and second surfaces of a first substrate, respectively; forming first and second reflective layers on said first and second information-recorded surfaces; producing pits of third and fourth information-recorded surfaces onto first surfaces of second and third substrates, respectively; forming first and second semitransparent layers on said third and fourth information-recorded surfaces, respectively; and bonding said first semitransparent to said first reflective layer using a first bonding layer therebetween, and bonding said second semitransparent layer to said second reflective layer using a second bonding layer therebetween.
31. A method of producing an optical disk, comprising the steps of:
fixing first and second stampers form for making pits of respective first and second information-recorded surfaces to a molding machine; simultaneously forming the pits of the first and second information-recorded surfaces onto first and second surfaces of a first substrate, respectively; simultaneously forming first and second reflective layers on said first and second information-recorded surfaces; producing pits of third and fourth information-recorded surfaces onto first surfaces of second and third substrates, respectively; forming first and second semitransparent layers on said third and fourth information-recorded surfaces, respectively; and bonding said first semitransparent layer to said first reflective layer using a first bonding layer therebetween, and bonding said second semitransparent layer to said second reflective layer using a second bonding layer therebetween.
2. A high-density optical disk as claimed in
3. A high-density optical disk as claimed in
a first bonding layer formed between a first one of said semitransparent layers and a first one of said reflective layers; and a second bonded bonding layer formed between a second one of said semitransparent layers and a second one of said reflective layers; wherein each of said first and second bonding layers is 30-40 μm.
4. A high-density optical disk as claimed in
a first bonding layer formed between a first one of said semitransparent layers and a first one of said reflective layers; and a second bonded bonding layer formed between a second one of said semitransparent layers and a second one of said reflective layers; wherein each of said first and second bonding layers is 30-40 μm.
5. A high-density optical disk as claimed in
6. A high-density optical disk as claimed in
7. A high-density optical disk as claimed in
8. A high-density optical disk as claimed in
10. The optical disk as claimed in
11. The optical disk as claimed in
12. The optical disk as claimed in
a first reflective layer formed on said first information-recorded surface; a second reflective layer formed on said second information-recorded surface; a first semitransparent layer formed on said third information-recorded surface; and a second semitransparent layer formed on said fourth information-recorded surface.
13. The optical disk as claimed in
a first reflective layer formed on said first information-recorded surface; a second reflective layer formed on said second information-recorded surface; a first semitransparent layer formed on said third information-recorded surface; and a second semitransparent layer formed on said fourth information-recorded surface.
14. The optical disk as claimed in
a first bonding layer to bond with said first reflective layer and said first semitransparent layer; and a second bonding layer to bond with said second reflective layer and said second semitransparent layer.
15. The optical disk as claimed in
a first bonding layer to bond with said first reflective layer and said first semitransparent layer; and a second bonding layer to bond with said second reflective layer and said second semitransparent layer.
16. The optical disk as claimed in
17. The optical disk as claimed in
18. The optical disk as claimed in
19. The optical disk as claimed in
20. The optical disk as claimed in
21. The optical disk as claimed in
22. The optical disk as claimed in
24. The optical disk as claimed in
a second substrate formed to face said second information-recorded surface, wherein said second substrate has a first surface facing away from said second information-recorded surface and said first information-recorded surface facing said second information-recorded surface; and a third substrate formed to face said third information-recorded surface, wherein said third substrate has a first surface facing away from said third information-recorded surface and said fourth information-recorded surface facing said third information-recorded surface.
25. The optical disk as claimed in
a first semitransparent layer having a first surface contacting said first information recorded surface, and a second surface; a first bonding layer having a first surface contacting said second surface of said first semitransparent layer opposite that of said first surface of said first semitransparent layer, and a second surface; a first reflective surface a first surface contacting said second surface of said first bonding layer, and a second surface contacting said second information-recorded surface; a second semitransparent layer having a first surface contacting said fourth information-recorded surface, and a second surface; a second bonding layer having a first surface contacting said second surface of said second semitransparent layer opposite that of said first surface of said second semitransparent layer, and a second surface; and a second reflective surface having a first surface contacting said second surface of said second bonding layer, and a second surface contacting said third information-recorded surface.
26. The optical disk as claimed in
27. The optical disk as claimed in
29. The method as claimed in
placing targets at first and second surfaces, respectively, of a chamber of a sputter device; and simultaneously forming said first and second reflective layers on said first and second information-recorded surfaces.
30. The method as claimed in
32. The method as claimed in
placing targets at first and second surfaces, respectively, of a chamber of a sputter device; and simultaneously forming said first and second reflective layers on said first and second information-recorded surfaces.
33. The method as claimed in
0. 38. The method as claimed in
simultaneously forming first and second reflective layers on said first and second information-recorded surfaces; forming a semitransparent layer on said third information-recorded surface; and bonding said semitransparent layer to said first reflective layer using a bonding layer therebetween.
0. 50. The method as claimed in
0. 52. The optical disk as claimed in
0. 53. The optical disk as claimed in
0. 57. The method as claimed in
forming a reflective layer on said first information-recorded surface; forming a semitransparent layer on said second information-recorded surface; and bonding said semitransparent layer to said reflective layer using a bonding layer therebetween.
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1. Field of the Invention
The present invention relates to an optical recording medium from which recorded information is reproduced by using a laser and method of producing the same and, more particularly, to a high-density recording medium which can densely record the information and from which the information is reproduced.
2. Description of the Related Art
Recently, a study of a high-density optical disk which is spotlighted as audio and video recording media has actively been made. A digital video disk (DVD) system which is a representative example of an information transmission medium of high picture quality and high sound quality has brought about the concept of a multimedia age combining digital video information with audio information. The birth of the DVD system includes prospects for a vast commercial market as a substitute demand for video cassette recorders and laser disks which are analog video systems, in addition to achieving technical innovation regarding the digitization of the video and audio information. Therefore, a fabrication method of a high-density substrate which can increase recording capacity has been demanded to provide for a next generation multimedia market.
A technique for fabricating the high-density substrate is disclosed in Korean Patent Application No. 95-1802, assigned to the same assignee as the present invention. In the above Korean Patent Application No. 95-1802, as shown in
An object of the present invention is to provide a high-density optical disk which can increase recording capacity and ensure durability.
Another object of the present invention is to provide a high-density optical disk which can simplify work and raise yield.
Additional objects 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.
The foregoing objects of the present invention are achieved by providing a high-density optical disk which includes reflective layers respectively formed at both information-recorded surfaces of a first substrate, and semitransparent layers respectively formed at one information-recorded surface of each of second and third substrates. The second and third substrates are respectively bonded at both sides of the first substrate.
The present invention will be more specifically described with reference to the attached drawings.
These and other objects and advantages of the invention will become apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which:
In the following description, well known functions and constructions which may obscure the present invention are not described in detail.
To fabricate a typical optical disk, there is needed a series of processes, that is, a mastering process, a stamper making process, a disk molding process, reflective layer and protective layer forming processes, a post process, etc. The mastering process is to make a glass master by forming minute pits on a photoresist covered on a glass platter by a photolithography process. The stamper making process is to transfer the minute pits formed on the glass master onto a stamper by a nickel plating process. The disk molding process is to reproduce optical disk substrates in large quantities by using the stamper. Various disk molding processes are compression molding, injection molding, photopolymerization (2P), etc. An example of a conventional molding machine is shown in
In a preferred embodiment of the present invention, unlike a conventional disk molding process (for example, injection molding), the disk is molded by fixing 2 stampers in which information is recorded to both surfaces of a molding machine. Thereafter, information-recorded pits are formed at both (two opposite) surfaces of one substrate.
In the stamper making process for making the stampers, a track pitch is set to 0.6 μm for example. Moreover, the substrate structure indicated in
To reproduce the information from the optical disk of
In other words, the substrate 18A uses the SiC or SiN semitransparent layer 16A and the upper portion of the substrate 10 uses the Al or Al--Ti reflective layer 12A. Thus, when the red laser beam of 635 nm is detected, the reflectance sensed by the optical pickup of the upper layer of the optical disk is 30% in the case of an information layer of the semitransparent layer 16A and 44% in the case of an information layer of the reflective layer 12A. When the red laser is focused on the optical disk, the information layer of the semitransparent layer 16A is distinguishable from the information layer of the reflective layer 12A due to the difference of the reflectance therebetween.
The information of a lower layer of the optical disk is reproduced by an additional pickup installed thereat based on similar reflectances.
The following Table 1 shows the capacity of the inventive optical disk of
| TABLE 1 | |||||
| minimum | track | channel | recording | ||
| pit length | pitch | bit length | resolution | capacity | |
| conven- | 0.4 | 0.74 | 0.1333 | 0.01 | 9.4 |
| tional disk | (μm) | (μm) | (μm) | (μm) | (GB/disk) |
| inventive | 0.36 | 0.60 | 0.1197 | 0.01 | 30 |
| disk | (μm) | (μm) | (μm) | (μm) | (GB/disk) |
As shown in the above Table 1, while the conventional optical disk has a recording capacity of 9.4 Giga bytes (GB) per disk at a track pitch of 0.74 μm, the inventive optical disk has a recording capacity of 30 GB per disk at a track pitch of 0.6 μm.
The minimum pit length (pit length recorded on the optical disk) corresponds to 3 T and the channel bit length (bit length in processing data) corresponds to ⅓ of the minimum pit length. The factors having an effect on recording density are the minimum pit length, the track pitch and the number of information layers available for recording the information. The following calculation shows the recording capacity of the inventive optical disc of
Recording density increment effects in view of the Minimum Pit Length
Effects in view of the Track Pitch
The number of information Layers available for recording
Total Recording Capacity increment effects=(a)×(b)×(c)≈3.3
The minimum pit length and the track pitch are controlled by the capacity of a LBR (laser beam recorder). When the recording capacity of the conventional DVD is compared with the recording capacity of the present invention without respect to the above LBR of one factor having an effect on the recording density, the recording density of the present invention can be twice as much as that of the conventional DVD due to structural differences between the conventional DVD and the present invention through the disk molding process.
As stated previously, since there are 4 information layers, twice the recording capacity of the conventional DVD can be obtained. The DVD system has complicated processes since there is a need to fabricate a dual layer by the photopolymerization process. However, the inventive optical disk simplifies the work without the photopolymerization process and the yield can be raised. Furthermore, by bonding the substrates of 0.6 mm to the upper and lower portions of the substrate having both information-recorded surfaces, the durability can be improved.
In addition, the inventive optical disk has the substrates 18A and 18B each having a thickness of 0.6 mm, and not the protective layers of the conventional optical disk. Therefore, even though dust forms on the optical disk, having a thickness of 5 μm, for example, in the incident direction of a light beam, it is possible for the spot of the laser beam to be focused on the optical disk because a sufficient focusing distance exists between the substrate 18A or 18B and the substrate 10.
It should be understood that the present invention is not limited to the particular embodiment disclosed herein as the best mode contemplated for carrying out the present invention, but rather that the present invention is not limited to the specific embodiments described in this specification except as defined in the appended claims.
Ro, Myong-Do, Gill, Byeung-Lyong
| Patent | Priority | Assignee | Title |
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| 5805563, | Sep 19 1996 | COLUMBIA DIGITAL MEDIA, INC | Optical information recording medium on which a visible display having a stereoscopically view effect and a depth viewing effect can be made |
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