Title:
OPTICAL DISK
Document Type and Number:
Japanese Patent JP3170062
Kind Code:
B2
Abstract:
PURPOSE: To obtain the optical disk which is high in the dependency of the reflection factor on the intensity of incidence by using a reflecting film which is made of a tertiary nonlinear optical material with a prescribed, refractive index and has a prescribed multiple reflection factor and prescribed film thickness.
CONSTITUTION: The reflecting film of the optical disk having a 1st transmission film, the reflecting film, and a 2nd transmission film which are laminated in turn has center light intensity I0 and peripheral part light intensity Ie and is consisted of the tertiary nonlinear optical material which has a refractive index ηII = η0+η2.Iin (η0: linear refractive index, η2: nonlinear refractive index) for a laser beam spot having an intensity distribution Iin shown by a Bessel function. Further, the film has the multiple reflection factor R shown by an equation I and film thickness (h) within a range shown by an expression II (η I: refractive index of the 1st transmission film, η III: refractive index of the 2nd transmission film, λ: wavelength of incident laser beam). This constitution improves the reflection factor-light intensity dependency of the reflecting film and the optical disk which whose reflection factor has high dependency on the incident light intensity can be obtained.
Inventors:
Takumaro Yanagisawa
Seiichi Ohsawa
Seiichi Ohsawa
Application Number:
JP25670392A
Publication Date:
May 28, 2001
Filing Date:
September 25, 1992
Export Citation:
Assignee:
Pioneer Corporation
International Classes:
G11B7/24062; (IPC1-7): G11B7/24
Domestic Patent References:
| JP684199A | ||||
| JP660425A | ||||
| JP5109119A |
Attorney, Agent or Firm:
Motohiko Fujimura