OPTICAL HEAD TO WRITE ON OPTICAL DISK AND/OR READING OFF FROM OPTICAL DISK PHASE-ONLY SYNTHETIC HOLOGRAM TO BE USED IN SAID OPTICAL HEAD Russian patent published in 2011 - IPC G11B7/00 

FIELD: physics.

SUBSTANCE: optical head comprises encased laser source, diffraction lattice to generate diffraction beam of rays of zero and ±1^st order, light splitting cure, phase-only synthetic hologram with positive optical force, collimated beam polarisation plate, lens of positive optical force, as well as astigmatic lens and photo detector to detect light beam reflected from disk. Lens is arranged ahead of optical disk to displace there along. Phase-only synthetic hologram may displace along optical axis and generate zero and ±1^st order collimated beams at outlet and reduce lengthwise chromatic aberration of zero-order beams originating in data write/read process. Phase-only synthetic hologram comprises collimator lens with first flat and second diffraction surfaces formed in compliance with phase factor defined by formula specified in invention claim.

EFFECT: higher accuracy and reliability of writing/reading.

9 cl, 8 dwg