US6618349B2
Expired / Lapsed
US
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Optical recording medium and its designing method
Assignee: TDK Corp
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Filing: 2001-02-21
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Granted: 2003-09-09
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Expires: 2021-02-21
Abstract
Abstract In an optical recording medium of land/groove recording system, a sufficient tilt margin and a reduced cross talk are realized simultaneously with a sufficiently increased output. Provided is an optical recording medium having a light-transmitting substrate formed with grooves wherein the grooves and the region between adjacent grooves are used for the recording track, and a reading beam is irradiated through the light-transmitting substrate, wherein the relations: −12.6 T +15.6≦ x ≦25 T −3.8, and 0.55≦ T ≦0.68 are satisfied when the reading beam has a wavelength of λ, the light-transmitting substrate has a refractive index at the wavelength λ of n, the reading optical system has a numerical aperture of NA, recording track pitch is P T , the groove has a depth of λ/(x·n), and T is P T /(λ/NA).
Inventors
- 👤 Hiroyasu Inoue
- 👤 Hajime Utsunomiya
- 👤 Hiroshi Shingai
- 👤 Tetsuro Mizushima
- 👤 Tatsuya Kato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:03
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/007
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
104 words
An optical recording medium having a light-transmitting substrate formed with grooves wherein the grooves and the region between adjacent grooves are used for the recording track, and a reading beam is irradiated through the light-transmitting substrate, wherein the relations: −12.6 T+ 15.6 ≦x≦ 25 T− 3.8, and 0.55 ≦T≦ 0.68 are satisfied when the reading beam has a wavelength of λ, the light-transmitting substrate has a refractive index at the wavelength λ of n, the reading optical system has a numerical aperture of NA, recording track pitch is P T , the groove has a depth of λ/(x·n), and T is P T /(λ/NA).
Claim 2
Dependent Claim
104 words
An optical recording medium having a light-transmitting substrate formed with grooves wherein the grooves and the region between adjacent grooves are used for the recording track, and a reading beam is irradiated through the light-transmitting substrate, wherein the relations: −12.6 T+ 15.6 ≦x≦ 25 T− 3.8, and 0.55 ≦T≦ 0.68 are satisfied when the reading beam has a wavelength of λ, the light-transmitting substrate has a refractive index at the wavelength λ of n, the reading optical system has a numerical aperture of NA, recording track pitch is P T , the groove has a depth of λ/(x·n), and T is P T /(λ/NA).
Claim 3
Dependent Claim
23 words
An optical recording medium according to claim 1 wherein said medium is used in combination with a reading optical system wherein NA≧ 0.6.
Claim 4
Independent Claim
115 words
A method for designing an optical recording medium having a light-transmitting substrate formed with grooves wherein the grooves and the region between adjacent grooves are used for the recording track, and a reading beam is irradiated through the light-transmitting substrate, wherein the groove is designed to have a depth satisfying the relations: −12.6 T+ 15.6 ≦x≦ 25 T− 3.8, and 0.55 ≦T≦ 0.68 when the reading beam has a wavelength of λ, the light-transmitting substrate has a refractive index at the wavelength λ of n, the reading optical system has a numerical aperture of NA, recording track pitch is P T , the groove has a depth of λ/(x·n), and T is P T /(λ/NA).
Claim 5
Independent Claim
115 words
A method for designing an optical recording medium having a light-transmitting substrate formed with grooves wherein the grooves and the region between adjacent grooves are used for the recording track, and a reading beam is irradiated through the light-transmitting substrate, wherein the groove is designed to have a depth satisfying the relations: −12.6 T+ 15.6 ≦x≦ 25 T− 3.8, and 0.55 ≦T≦ 0.68 when the reading beam has a wavelength of λ, the light-transmitting substrate has a refractive index at the wavelength λ of n, the reading optical system has a numerical aperture of NA, recording track pitch is P T , the groove has a depth of λ/(x·n), and T is P T /(λ/NA).
Claim 6
Dependent Claim
22 words
A method for designing an optical recording medium according to claim 3 wherein the medium is designed by assuming that: NA≧ 0.6.
References Cited (Backward Citations)
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| 3.5 Years (Year 4) | 2006-09-08 | 2007-03-10 | 2007-09-09 | $2000.00 | Window Closed / Lapsed |
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