Samsung Electronics Co., Ltd.

Kun-Mo Cho

Chong-sam Chung

Chul-woo Lee

Jang-hoon Yoo

Pyong-yong Seong

Young-min Cheong

Dong-Ho Shin

Joong-Eon Seo

Cheol-sung Yeon

Yong-Moon Lee

An optical focusing system which uses a light beam emitted from a light source, includes a refractive surface on one side of the optical focusing system and having a first radius of curvature, a first reflection surface on the above one side, surrounding the refractive surface and having a second radius of curvature being different from the first radius of curvature, a transparent beam focusing surface on the other side of the optical focusing system, and a second reflection surface on the above other side and surrounding the beam focusing surface. The refractive surface refracts an incident light beam, the second reflection surface reflects a light beam refracted by the refractive surface toward the first reflection surface, and the first reflection surface focuses a laser light beam reflected from the second reflection surface on the beam focusing surface as a focused beam spot. The optical focusing system can be used in an optical pickup. The optical pickup uses the optical focusing system to generate, from a light beam e.g. laser light emitted from a light source, a beam spot used for recording or reading information to a recording medium. The optical pickup uses a near field effect provided by an optical focusing system according to the present invention, to allow a superior density of recording or reading. Further, the optical focusing system according to the invention can use a light beam having a beam diameter smaller than that of the laser beam used for an existing optical focusing system for forming a near field. Thus, the optical pickup according to the invention can record or read information on an optical disk having a surface recording density of 10 Gbit/inch,or more. Even if an incident light beam inclination occurs due to movement of the disk or the optical pickup, information can be recorded on or read from a disk accurately. Also, the assembly of the optical focusing system and the adjustment of the assembled optical focusing system are easily performed.

Catadioptric optical system, optical pickup and optical disk drive employing the same, and optical disk

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Suwon, South Korea

Kun-Mo Cho