Patent ID: 7177259

Claim:
An optical head comprising: a light source; light converging means for converging light beams emitted from the light source onto an optical recording medium to irradiate them; light separating means for separating light beams emitted from the light source and reflected light beams which have been reflected by the optical recording medium and have been passed through the converging means; light detecting means for receiving reflected light beams from the optical recording medium which have been separated by the light separating means; and light coupling efficiency adjustable means provided between the light source and the light separating means, and serving to change or adjust light coupling efficiency which is percentage (ratio) of light quantity converged onto the optical recording medium to total light quantity emitted from the light source, wherein the light separating means has a reflection surface in a plane form which is inclined with respect to the optical axis of incident light beams emitted from the light source and incident on the light separating means via the light coupling adjustable means, whereby the incident light beams which are P-polarized light are incident on the reflection surface to allow a predetermined percentage of the incident light beams to be reflected by the reflection surface to separate the reflected light beams to send them to a light detector for detecting emission power of the light source, and to allow the remaining portion of the incident light beams to be transmitted through the reflection surface to send the transmitted light beams to the light converging means.