PURPOSE: To simplify the cutting process by irradiating an optical disc with continuously oscillating laser light subjected to intensity modulation and forming a signal groove therein thereby eliminating the step for applying photoresist and the step for development.
CONSTITUTION: A single mode continuous oscillation laser light is fed from a UV laser light source 1 through a mirror 2 to an acoustooptical modulation element 3 where the laser light is subjected to intensity modulation with a signal fed from a formatter 4 and outputted as an optical modulation pulse. It is fed through a mirror 5 to a beam expander 6 where the beam diameter is enlarged and the beam passes through mirrors 7, 8 and impinges on the incident pupil face of an objective lens 9 before being condensed onto an original optical disc 13 with a spot size of diffraction limit by adjusting the focus. An optical system including a lens 9 is then shifted from the outer circumference to the center in order to expose the original disc 13 spirally thus recording signals through abrasion.
TAKEDA MINORU
Next Patent: SURFACE TREATMENT METHOD FOR STAMPER