SIL near-field flying head structure to control gap between disc and SIL with three sensor points in front of lens holder

A SIL (solid immersion lens) near-field flying head flying state control structure for controlling a flying head to perform near-field recording on an optical disk, comprising

• a slider;
• a semispherical SIL (solid immersion lens) located on a front side of said slider, said SIL having a spherical face and a tangent plane facing said optical disk;
• a focusing lens provided in said slider corresponding to the spherical face of said SIL;
• wherein said slider has a base to be maintained at a distance in close proximity to said optical disk, and a lens holder for holding said SIL and said focusing lens, said lens holder being capable of biasing elative to said base;
• a distance detection unit having at least three detection points disposed in a front side of said lens holder around the tangent plane of said SIL for enabling said distance detection unit to detect the distance between each of said at least three detection points and said optical disk;
• a posture control unit having a plurality of single-axis displacement devices provided between the base and lens holder of said slider for controlling relative movement between said lens holder and said base in direction parallel to the optical axis of said SIL, so as to further achieve control of the posture of said lens holder relative to said base;
• and
• a server adapted to determine the direction and amount of tilting of the tangent plane of said SIL relative to said optical disk subject to the distance between every of said detection points and said optical disk detected by said distance detection unit, and to command said single-axis displacement devices of said posture control unit to adjust the relative position between said lens holder and said base subject to the direction and amount of tilting of the tangent plane of said SIL relative to said optical disk, keeping the parallelism between the tangent plane of said SIL and said optical disk controlled within a predetermined level.