Claims
- 1. An optical disk with sectional trapezoidal pits comprising:
- a substrate having information recorded by a plurality of pit trains formed thereon at a specified track pitch; and
- a reflective layer formed on the substrate, wherein the information is reproduced by being irradiated with light beam via an objective lens, the track pitch is set within the range of (0.72 to 0.8) .alpha..times..lambda./NA/1.14 .mu.m when a wavelength of the light beam is .lambda. .mu.m and a numerical aperture of the objective lens is NA, each of the pits is scaled by the multiplication ratio .alpha. used to secure allowable disk tilt angles, an upper width of each of the pits is within the range of (0.3 to 0.50) .alpha..times..lambda./NA/1.14 .mu.m, a bottom width of the pits is within the range of (0.2 to 0.32) .alpha..times..lambda./NA/1.14 .mu.m and a depth of the pits is within the range of (1/4.2.times..lambda./n) to (1/5.2.times..lambda./n) (n: refractive index of said substrate and .lambda.: a wavelength of 0.65 .mu.m) and .alpha. obtained by 2.623.times.10.sup.-7 .times.(d.sub.s /.lambda.).sup.2 -1.706.times.10.sup.-4 (d.sub.s /.lambda.)+0.934 m (d.sub.s : thickness of the substrate).
- 2. An optical disk according to claim 1, wherein the substrate is composed of a pair of transparent substrates in which information is recorded and the reflective layer is formed on a pair of reflective films formed between the pair of transparent substrates.
- 3. An optical disk according to claim 2, wherein a pair of protective films are formed on the reflective films and these protective films are placed oppositely to each other and stuck.
- 4. An optical disk according to claim 3, wherein an adhesive layer for adhering the protective layers to each other is formed therebetween.
- 5. An optical disk according to claim 1, wherein the substrate is formed of at least one of polycarbonate and acrylic resins.
- 6. An optical disk according to claim 1, including a second substrate and a second reflective layer formed on this second substrate.
- 7. An optical disk according to claim 1, including protective layers formed on the reflective layer.
- 8. An optical disk apparatus comprising:
- an optical disk formed of a substrate in which information is recorded as pit trains formed on the substrate at a specified track pitch and a reflective layer formed on the substrate;
- an objective lens provided oppositely to the optical disk;
- means for irradiating the optical disk with light beam via the objective lens; and
- means for detecting reflective light of the light beam with which the optical disk is irradiated by the irradiating means and reproducing information recorded in the optical disk,
- wherein when a wavelength of the light beam is .lambda. .mu.m and a numerical aperture of the objective lens is NA, the track pitch is set within the range of (0.72 to 0.8) .alpha..times..lambda./NA/1.14 .mu.m, each of the pits is scaled by the multiplication ratio .alpha. for securing allowable disk tilt angles, an upper width of each of the pits is within the range of (0.3 to 0.50) .alpha..times..lambda./NA/1.14 .mu.m, a bottom width within of the pits is within the range of (0.2 to 0.32) .alpha..times..lambda./NA/1.14 .mu.m and a depth of the pits is within the range of (1/4.2.times..lambda./n) to (1/5.2.times..lambda./n) (n: refractive index of a substrate and .lambda.: a wavelength) and .alpha. is obtained by 2.623.times.10.sup.-7 .times.(d.sub.s /.lambda.).sup.2 -1.706.times.10.sup.-4 (d.sub.s /.lambda.)+0.934 where d.sub.s is thickness of the substrate in units of .mu.m.
- 9. An optical disk apparatus according to claim 8, wherein the reproducing means generates a push-pull signal and a reproducing signal for indicating a difference between signals detected at least in two areas in a track direction and the pits have depths set so that both levels of the push-pull and reproducing signals indicate large values.
- 10. An optical disk apparatus according to claim 8, wherein the reproducing means is provided with a function of extending information compressed and recorded in the optical disk in accordance with MPEG 2 and reproducing original image information.
- 11. An optical disk with sectional trapezoidal pits comprising:
- a substrate in which information is recorded as pit strings at a specified track pitch; and
- a reflective layer formed on the substrate,
- wherein the information is reproduced by being irradiated with light beam via an objective lens, when a wavelength of the light beam is .lambda. .mu.m and a numerical aperture of the objective lens is NA, the track pitch is set within the range of (0.72 to 0.8) .alpha..times..lambda./NA/1.14 .mu.m, each of the pits is scaled by the multiplication ratio .alpha. for securing allowable disk tilt angles, an upper width of each of the pits is within a range of (0.3 to 0.5) .alpha..times..lambda./NA/1.14 .mu.m, an angle of an inner wall of the pits is within a range from 30.degree. to 60.degree. and a depth of the pits is within the range of (1/4.2.times..lambda./n) to (1/5.2.times..lambda./n) (n: refractive ratio of a substrate and .lambda.: a wavelength) and .alpha. obtained by 2.623.times.10.sup.-7 .times.(d.sub.s /.lambda.).sup.2 -1.706.times.10.sup.-4 (d.sub.s /.lambda.)+0.934 where d.sub.s is thickness of the substrate in units of .mu.m.
- 12. An optical disk according to claim 11, wherein the substrate is composed of a pair of transparent substrates in which information is recorded and the reflective layer is formed of a pair of reflective films formed between the pair of transparent substrates.
- 13. An optical disk according to claim 12, wherein a pair of protective films are formed on the reflective films and these protective films are placed oppositely to each other and stuck.
- 14. An optical disk according to claim 13, wherein an adhesive layer for sticking the protective layers to each other is formed therebetween.
- 15. An optical disk according to claim 11, wherein the substrate is formed of at least one of polycarbonate and acrylic resins.
- 16. An optical disk according to claim 11, including a second substrate and a second reflective layer formed on this substrate.
- 17. An optical disk according to claim 11, including protective films formed on the reflective layer.
- 18. An optical disk apparatus comprising:
- an optical disk composed of a substrate in which information is recorded as pit strings at a specified track pitch and a reflective layer formed on the substrate;
- an objective lens provided oppositely to the optical disk;
- means for irradiating the optical disk with light beam via the objective lens; and
- means for detecting reflective light of the light beam with which the optical disk is irradiated by the irradiating means and reproducing information recorded in the optical disk,
- wherein when a wavelength of the light beam is .lambda. .mu.m and a numerical aperture of the objective lens is NA, the track pitch is set within the range of (0.72 to 0.8) .alpha..times..lambda./NA/1.14 .mu.m, each of the pits is scaled by the multiplication ratio .alpha. for securing allowable disk tilt angles, an upper width of each of the pits is within the range of (0.3 to 0.5 ) .alpha..times..lambda./NA/1.14 .mu.m, an angle of an inner wall of the pits is within a range 30.degree. to 60.degree. and a depth within the range of (1/4.2.times..lambda./n) to (1/5.2.times..lambda./n) (n: refractive index of a substrate and .lambda.: a wavelength) and obtained by 2.623.times.10.sup.-7 .times.(d.sub.s /.lambda.).sup.2 -1.706.times.10.sup.-4 (d.sub.s /.lambda.)+0.934 where d.sub.s is thickness of the substrate in units of .mu.m.
- 19. An optical disk apparatus according to claim 18, wherein the reproducing means generates a push-pull signal and a reproducing signal for indicating a difference between signals detected in at least two areas in a track direction and the pits have depths set so that both levels of the push-pull and reproducing signals are large values.
- 20. An optical disk apparatus according to claim 18, wherein the reproducing means is provided with a function of extending information compressed and recorded in the optical disk in accordance with MPEG 2 and reproducing original image information.
- 21. An optical disk with sectional trapezoidal pits comprising:
- a substrate having information recorded by a plurality of pit trains formed thereon at a specified track pitch; and
- a reflective layer formed on the substrate, wherein the information is reproduced by being irradiated with light beam via an objective lens, the track pitch is set within the range of (0.72 to 0.8) .alpha..times..lambda./NA/1.14 .mu.m when a wavelength of the light beam is .lambda. .mu.m and a numerical aperture of the objective lens is NA, each of the pits is scaled by the multiplication ratio .alpha. used to secure allowable disk tilt angles, an upper width of each of the pits is within a range of (0.3 to 0.50).times..lambda./NA/1.14 .mu.m, a bottom width of the pits is within the range of (0.2 to 0.32).times..lambda./NA/1.14 .mu.m and a depth of the pits is within the range of (1/4.2.times..lambda./n) to (1/5.2.times..lambda./n) (n: refractive index of said substrate and .lambda.: a wavelength 0.65 .mu.m) and .alpha. obtained by 2.623.times.10.sup.-7 .times.(d.sub.s /.lambda.).sup.2 -1.706.times.10.sup.-4 (d.sub.s /.lambda.)+0.934 m where d.sub.s is thickness of the substrate in units of .mu.m.
- 22. An optical disk apparatus comprising:
- an optical disk formed of a substrate in which information is recorded as pit trains formed on the substrate at a specified track pitch and a reflective layer formed on the substrate;
- an objective lens provided oppositely to the optical disk;
- means for irradiating the optical disk with light beam via the objective lens; and
- means for detecting reflective light of the light beam with which the optical disk is irradiated by the irradiating means and reproducing information recorded in the optical disk,
- wherein when a wavelength of the light beam is .lambda. .mu.m and a numerical aperture of the objective lens is NA, the track pitch is set within the range of (0.72 to 0.8) .alpha..times..lambda./NA/1.14 .mu.m, each of the pits is scaled by the multiplication ratio .alpha. for securing allowable disk tilt angles, an upper width of each of the pits is within the range of (0.3 to 0.50).times..lambda./NA/1.14 .mu.m, a bottom width of the pits is within the range of (0.2 to 0.32).times..lambda./NA/1.14 .mu.m and a depth of the pits is within the range of (1/4.2.times..lambda./n) to (1/5.2.times..lambda./n) (n: refractive index of a substrate and .lambda.: a wavelength) and .alpha. is obtained by 2.623.times.10.sup.-7 .times.(d.sub.s /.lambda.).sup.2 -1.706.times.10.sup.-4 (d.sub.s /.lambda.)+0.934 where d.sub.s is thickness of the substrate in units of .mu.m.
- 23. An optical disk with sectional trapezoidal pits comprising:
- a substrate in which information is recorded as pit strings at a specified track pitch; and
- a reflective layer formed on the substrate,
- wherein the information is reproduced by being irradiated with light beam via an objective lens, when a wavelength of the light beam is .lambda. .mu.m and a numerical aperture of the objective lens is NA, the track pitch is set within the range of (0.72 to 0.8) .alpha..times..lambda./NA/1.14 .mu.m, each of the pits is scaled by the multiplication ratio .alpha. for securing allowable disk tilt angles, an upper width of each of the pits is within the range of (0.3 to 0.5).times..lambda./NA/1.14 .mu.m, an angle of an inner wall of of the pits is within a range from 30.degree. to 60.degree. and a depth of the pits is within the range of (1/4.2.times..lambda./n) to (1/5.2.times..lambda./n) (n: refractive ratio of a substrate and .lambda.: a wavelength) and .alpha. is obtained by 2.623.times.10.sup.-7 .times.(d.sub.s /.lambda.).sup.2 -1.706.times.10.sup.-4 (d.sub.s /.lambda.)+0.934 where d.sub.s is thickness of the substrate in units of .mu.m.
- 24. An optical disk apparatus comprising:
- an optical disk composed of a substrate in which information is recorded as pit strings at a specified track pitch and a reflective layer formed on the substrate;
- an objective lens provided oppositely to the optical disk;
- means for irradiating the optical disk with light beam via the objective lens; and
- means for detecting reflective light of the light beam with which the optical disk is irradiated by the irradiating means and reproducing information recorded in the optical disk,
- wherein when a wavelength of the light beam is .lambda. .mu.m and a numerical aperture of the objective lens NA, the track pitch is set within the range of (0.72 to 0.8) .alpha..times..lambda./NA/1.14 .mu.m, each of the pits is scaled by the multiplication ratio .alpha. for securing allowable disk tilt angles, an upper width of each of the pits is within the range of (0.3 to 0.5).times..lambda./NA/1.14 .mu.m, an angle of an inner wall of the pits is within the range from 30.degree. to 60.degree. and a depth of the pits is within the range of (1/4.2.times..lambda./n) to (1/5.2.times..lambda./n) (n: refractive index of a substrate and .lambda.: a wavelength) and .alpha. is obtained by 2.623.times.10.sup.-7 .times.(d.sub.s /.lambda.).sup.2 -1.706.times.10.sup.-4 (d.sub.s /.lambda.)+0.934 where d.sub.s is thickness of the substrate in units of .mu.m.
Priority Claims (5)
Number |
Date |
Country |
Kind |
6-004230 |
Jan 1994 |
JPX |
|
6-002934 |
Mar 1994 |
JPX |
|
9418355 U |
Sep 1994 |
DEX |
|
94114369 |
Sep 1994 |
EPX |
|
1994-23136 |
Sep 1994 |
KRX |
|
CROSS REFERENCE TO THE RELATED APPLICATION
This is a continuation-in-part of copending prior application Ser. No. 08/475,494, filed Jun. 7, 1995, which is a continuation of U.S. patent application Ser. No. 08/304,849, filed Sep. 13, 1994, now U.S. Pat. No. 5,459,712.
US Referenced Citations (6)
Foreign Referenced Citations (4)
Number |
Date |
Country |
0132137A2 |
Jan 1985 |
EPX |
0132137B1 |
Dec 1990 |
EPX |
0553573A1 |
Aug 1993 |
EPX |
0553541A1 |
Aug 1993 |
EPX |
Non-Patent Literature Citations (4)
Entry |
Jozef Braat, Principles of Optical Disc Systems, Ch.2, "Read-out of Optical Discs," Sec. 2.2.3. 1985, pp. 17-19. |
Teraeo et al, Fundamentals of Optical Memory, "Recordable and Erasable Optical Memory Medium", 1990, pp. 60-61. |
K. Yamada et al, "Tracking Method for Optical Disk Systems with Composite Detection", Abstracts of Lectures given at the 54th Meeting of the Japanese Society of Applied Physics Sep. 27, 1993, 28a-SF-16, p. 1009. |
Sugaya et al, "Performance of a 600 Mbyte 90 mm Phase-Change Optical Disk Tilt", Jpn.ApplPhys., vol. 32 (1993), pp. 5402-5405. |
Continuations (1)
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Number |
Date |
Country |
Parent |
304849 |
Sep 1994 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
475494 |
Jun 1995 |
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