Information recording carrier and information reproducing apparatus for the same
View Patent ↗Plural grooves or lands formed in an information recording carrier include at least a wobbling region and data is recorded wobblingly in this wobbling region by phase shift modulation while recorded digitally with a single or multiple waves as a channel bit.
1. An information recording carrier having minute pattern including plural grooves formed to be substantially in parallel and adjacent each other, comprising:
a supporting body having the minute pattern;
a recording layer formed on the minute pattern formed on the supporting body; and
a light transmission layer formed on the recording layer,
wherein the minute pattern is formed under a relation of P<λ, /NA, where P represents a distance between centers of adjacent grooves, λ, represents a wavelength of a laser beam between 350 nm and 450 nm, and NA represents a numerical aperture of an objective lens between 0.85 and 0.9,
wherein the plural grooves include at least a wobbling region,
wherein said wobbling region records, as wobble, data modulated by phase shift modulation,
wherein the thickness of light transmission layer is from 0.02 to 0.12 mm,
wherein said recording layer is subject to the laser beam having passed said light transmission layer, and
wherein the data modulated by phase shift modulation show information concerning a size of the information recording carrier.
2. The information recording carrier according to claim 1 , wherein a minimum phase difference of phase portions composing the phase shift modulation is set within from π/8 to π.
3. The information recording carrier according to claim 2 , wherein the phase shift modulation is composed of two phase portions and the minimum phase difference is π.
4. An information reproducing apparatus for reproducing information recorded in the information recording carrier according to claim 1 , the apparatus comprising:
a light emitting element configured tot emit laser beam at least having said wavelength λ;
an objective lens having said numerical aperture NA; and
a pickup having a photodetector,
wherein said objective lens is arranged so as to oppose said light transmission layer.
5. The information reproducing apparatus according to claim 4 , further comprising a demodulator demodulating reproduced signal outputted from said pick-up, wherein the reproduced signal shows information concerning the size of the information recording carrier.