Optical information recording medium having first and second pit row of identical reflectance
AssigneesSharp Kabushiki Kaisha, Memory-Tech Holdings Inc.
InventorsTakayuki Naka, Hirohisa Yamada, Masaki Yamamoto, Hideharu Tajima, Masahito Konishi
Life of this patent
Estimating the term…
Abstract
In a case where (i) a reflectance calculated from a reflected light amount obtained from a longest pit (P1max) or a longest space (S1max) in a first pit row is defined as a first reflectance and (ii) a reflectance calculated from a reflected light amount obtained from a longest pit (P2max) or a longest space (S2max) in the second pit row is defined as a second reflectance, the first pit row is formed such that the first reflectance becomes substantially identical with the second reflectance.
Claims4
An optical information recording medium comprising:
- a recording layer which includes (i) a first region in which information is recorded by a first pit row that includes a pit whose length is shorter than that of an optical system resolution limit of a reproduction device and (ii) a second region in which information is recorded by a second pit row that is made up of pits whose length is equal to or longer than that of the optical system resolution limit,
- in a case where (i) a reflectance calculated from a reflected light amount obtained from a longest pit or a longest space in the first pit row is defined as a first reflectance and (ii) a reflectance calculated from a reflected light amount obtained from a longest pit or a longest space in the second pit row is defined as a second reflectance,
- the first pit row being formed such that the first reflectance becomes substantially identical with the second reflectance, and
- polarity information for identifying a pit polarity being recorded in the second region.
An optical information recording medium which is to be reproduced by a reproduction device that (i) emits reproduction light having a wavelength of 405 nm and (ii) includes an objective lens having a numerical aperture of 0.85, said optical information recording medium comprising:
- a recording layer which includes (i) a first region in which information is recorded by a first pit row that includes a pit whose length is shorter than 119 nm and (ii) a second region in which information is recorded by a second pit row that is made up of pits whose length is equal to or longer than 119 nm,
- in a case where (i) a reflectance calculated from a reflected light amount obtained from a longest pit or a longest space in the first pit row is defined as a first reflectance and (ii) a reflectance calculated from a reflected light amount obtained from a longest pit or a longest space in the second pit row is defined as a second reflectance,
- the first pit row being formed such that the first reflectance becomes substantially identical with the second reflectance, and
- polarity information for identifying a pit polarity being recorded in the second region.
Dependencies are inferred from the claim text.