CATADIOPTRIC OPTICAL SYSTEM, FOR OPTICAL REPRODUCING HEAD AND OPTICAL-DISK MEMORY; OPTICAL DISK Russian patent published in 2001 - IPC

FIELD: optoelectronics. SUBSTANCE: optical focusing system has refracting area of first curvature radius on its one side; first reflecting surface of second curvature radius differing from first one that surrounds refracting surface; transparent beam-focusing surface on other side of system; and second reflecting surface on mentioned other side of system that surrounds beam-focusing surface. Refracting surface serves to refract incident light beam; second reflecting surface reflects light beam refracted by refracting surface to first reflecting surface and the latter focuses laser beam reflected from second reflecting surface onto beam focusing surface in the form of focused light spot. Optical focusing system may be incorporated in optical reproducing head to produce light spot from light or laser beam emitted by light source for recording or reading records residing on record medium. Novelty is that optical reproducing head uses nearby-area field effect to obtain superhigh bit density. In addition, optical focusing system may use light beam of diameter smaller than that of laser beam used by known optical focusing system for shaping field in nearby area. In this way reproducing head can write information on or read it out of optical disk having surface bit density of 1.55 Gbit/sq. Cm (10 Gbit/sq. In.) or more. Proposed system provides for precision writing information on or reading it off the optical disk in case of incident beam deflection due to movement of disk or optical system. EFFECT: facilitated assembly and adjustment of optical focusing system. 67 cl, 29 dwg