Lens unit for optical pick-up apparatus, optical element for optical pick-up apparatus, lens frame for lens unit, assembly method of the lens unit, and optical pick-up apparatus

摘要

The lens unit for the optical pick-up apparatus has: the objective lens (1) by which the projecting light from the light source is condensed on the information recording surface of the optical information recording medium; the phase control element (2) which is arranged on the light source side to the objective lens, and which controls the phase of the projecting light from the light source; and the supporting member (3) holding the objective lens and the phase control element; and the phase control element is held under the condition that its optical axis is inclined by a predetermined angle to the optical axis of the objective lens, and the intersection at which the optical axis of the phase control element crosses the optical surface having the phase structure is arranged on the optical path passing through the central point which passes the optical axis of the objective lens.