Dynamic information storage or retrieval – With servo positioning of transducer assembly over track... – Optical servo system
Reexamination Certificate
2006-07-11
2006-07-11
Edun, Muhammad (Department: 2656)
Dynamic information storage or retrieval
With servo positioning of transducer assembly over track...
Optical servo system
C369S112010, C369S112030
Reexamination Certificate
active
07075865
ABSTRACT:
An optical pickup includes a semiconductor laser for emitting light at a wavelength λ1and a semiconductor laser for emitting light at a different wavelength λ2from the wavelength λ1.The light at the wavelength λ1transmitted through an objective lens forms a light-collecting spot on an optical disk to record/reproduce information thereon. The light at the wavelength λ2transmitted through the objective lens forms a light-collecting spot on an optical disk to record/reproduce information thereon, the two optical disks having different substrate thicknesses. Between the semiconductor laser and the objective lens is there provided a combination-type diffractive element fabricated by combining two raw materials having different refractive index behaviors in relation to wavelength at a combining plane shaped as a grating. The structure facilitates good recording/reproduction on the two types of recording media irrespective of the reproduction wavelengths or substrate thicknesses of the recording media.
REFERENCES:
patent: 6574182 (2003-06-01), Yamada et al.
patent: 6618344 (2003-09-01), Funato
patent: 8-55363/1996 (1996-02-01), None
“Extended Abstracts” No. 3 (The Japan Society of Applied Physics and Related Societies, The 43rd Spring Meeting, 1996, pp. 1084, Lecture No. 28a-F-7). English translation provided.
Nishioka Sumito
Ogata Nobuo
Conlin David G.
Edun Muhammad
Manus Peter J.
Sharp Kabushi Kaisha
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