Patent ID: 8503272

Claim:
A method of focusing a light source onto an optical memory medium in an optical device compatible with different types of optical memory media, said method comprising: generating an information signal to control emission of a light from a light emitting source; focusing a first portion of said light onto said optical memory medium independent of a type of said optical memory medium; focusing a second portion of said light onto said optical memory medium if said optical memory medium is a first predetermined type; focusing a third portion of said light onto said optical memory medium if said optical memory medium is a second predetermined type; and processing the first through third portions of said light, wherein: a first working distance between an objective lens and a near surface of said optical memory medium of said first predetermined type having a first thickness is other than a second working distance between said objective lens and a near surface of said optical memory medium of said second predetermined type having a second thickness other than the first thickness, and only said first and second portions of said light are focused onto said optical memory medium if said optical memory medium is said first predetermined type and said first and third portions of said light are focused onto said optical memory medium if said optical memory medium is said second predetermined type.