Patent ID: 8009543

Claim:
A hologram optical device provided in an optical pickup, the optical pickup comprising an objective lens and a light source configured to emit an incident light along an optical axis, the hologram optical device comprising: a first hologram area comprising a hologram that is asymmetric with respect to the optical axis and is configured to: diffract the incident light to produce a first 0 th order diffractive light and a first 1 st order diffractive light; and diverge the first 1 st order diffractive light; and a second hologram area provided outside of the first hologram area and comprising a hologram configured to: diffract the incident light to produce a second 0 th order diffractive light and a second 1 st order diffractive light; and converge the second 1 st order diffractive light; wherein the objective lens is configured to: focus the first 0 th order diffractive light to form a first light spot on the optical axis; and focus the first 1 st order diffractive light to form a second light spot at a predetermined distance from the optical axis in a direction perpendicular to the optical axis.