Patent ID: 7564767

Claim:
An optical recording medium driving device for recording and/or reproducing signals for at least two types of optical recording media having respective different values of recording and/or reproducing power, comprising: an optical head for emitting a light beam on said optical recording medium; an optical coupling efficiency varying device configured to vary an optical coupling efficiency, the efficiency being a ratio of a light volume of a light beam condensed on said optical recording medium to a light volume of a light beam emitted by said optical head; an optical coupling efficiency controlling device configured to control the optical coupling efficiency varying device; said optical coupling efficiency controlling device configured to control said optical coupling efficiency varying device depending on the type of the optical recording media; and a temporal relationship controller configured to control a temporal relationship between a first timing of changing the optical coupling efficiency and a second timing of changing the light volume of light condensed on a recording surface of said optical recording medium, wherein said optical coupling efficiency varying device is formed by a filter device for lowering a transmittance of the light beam and a device for displacing said filter device, said optical coupling efficiency varying device includes an optical path branching device configured to branch an input light beam into at least two optical paths, and the ratio of branching of the light volume to said least two optical paths is varied to vary the optical coupling efficiency.