Patent ID: 8355303

Claim:
An optical disc reader comprising: a read laser operating in super-resolution mode, suitable for reading optical discs having a structure comprising: a substrate provided with physical marks having a geometrical configuration that defines recorded information; a superposition of three layers positioned above the physical marks of the substrate; and a transparent protective layer positioned above the superposition of three layers, wherein the superposition of three layers comprises an indium antimonide or gallium antimonide layer inserted between two dielectric layers of a zinc sulfide-silicon oxide compound; means for varying power of the read laser; means for measuring a reflectivity of a sensitive layer of an optical disc for at least four power levels; means for determining, in a plane representative of the reflectivity measurement as a function of the power of the read laser, a critical power located at a point of intersection of a straight line joining the reflectivity measurements for two power levels of the read laser and a straight line joining the reflectivity measurements for two other power levels of the read laser, and a desirable read power above the critical power; and means for applying the desirable read power for subsequently reading the recorded information present on the optical disc.