To provide a hologram optical device and an optical pickup device, which are capable of correctly detecting a focus state in an optical recording medium even when a diffracting angle of a feedback luminous flux is changed by wavelength variations of a light source and to provide an optical recording medium driving device using them.
A hexapartite hologram surface 40 is parted into areas Ha, Hb, Hc, Hd, He, Hf by parting lines 4L, 4M, 4N. A quadripartite photodetecting part 60 is parted into four photodetecting parts A, B, C, D having an equal area by a dividing line LX nearly parallel to the radial direction of an optical disk 1 and a dividing line LY orthogonal to it. Main luminous flux diffracted by areas Ha, Hd of the hexapartite hologram surface 40 is condensed as light condensing spots Sa, Sd in respectively opposite side separate positions on the dividing line LX of the quadripartite photodetecting part 60, and a main luminous flux diffracted by areas Hb, Hc, He, Hf is condensed as light condensing spots Sb, Sc, Se, Sf in the center of the photodetecting parts A, D, C, B of the quadripartite photodetecting part 60.
TAJIRI ATSUSHI
NISHIDA TOYOZO
INOUE YASUAKI
UEDA YASUHIRO
SHONO MASAYUKI
SAWADA MINORU
