Blue NA 0.85/DVD/CD compatible optical head

Author

Katayama, Ryuichi ; Komatsu, Yuichi

Author_Institution

Functional Devices Res. Labs., NEC Corp., Kawasaki, Japan

fYear

2002

fDate

2002

Firstpage

168

Lastpage

170

Abstract

In high density optical disk systems employing blue laser diodes, high NA (numerical aperture) objective lenses and thin cover layer disks, compatibility with conventional DVDs and CDs is strongly required. The authors have previously proposed a blue/DVD/CD compatible optical head, whose NA for the blue optical disk is 0.7. On the other hand, NA 0.85 single objective lenses have also become available, which are suitable for the compatibility requirements because of the long working distance. So, this paper further proposes a blue/DVD/CD compatible optical head, whose NA for the blue optical disk is 0.85. In order to realize the compatibility between different types of disks, it is necessary to correct the spherical aberration and control the NA for each disk. In this three-wavelength optical head, the spherical aberration is corrected by variable magnification, and the NA is controlled by a wavelength selective aperture.

Keywords

aberrations; lenses; optical disc storage; optical testing; semiconductor lasers; 405 nm; 660 nm; 785 nm; blue laser diodes; blue optical disk/DVD/CD compatible optical head; compatibility; high NA objective lenses; high density optical disk systems; lens working distance; multi-wavelength optical head; numerical aperture; single objective lenses; thin cover layer disks; variable magnification spherical aberration correction; wavelength selective aperture NA control; Apertures; DVD; Interference; Jitter; Laboratories; Lenses; National electric code; Optical design; Optical filters; Optical variables control;

fLanguage

English

Publisher

ieee

Conference_Titel

Optical Memory and Optical Data Storage Topical Meeting, 2002. International Symposium on

Print_ISBN

0-7803-7379-0

Type

conf

DOI

10.1109/OMODS.2002.1028603

Filename

1028603