| US 7,564,767 B2 | ||
| Optical recording medium driving device | ||
| Noriaki Nishi, Tokyo (Japan); and Kenji Yamamoto, Kanagawa (Japan) | ||
| Assigned to Sony Corporation, Tokyo (Japan) | ||
| Filed on Feb. 12, 2007, as Appl. No. 11/674,007. | ||
| Application 11/418254 is a division of application No. 10/307979, filed on Dec. 03, 2002, granted, now 7,173,898. | ||
| Application 11/674007 is a continuation of application No. 11/418254, filed on May 05, 2006, granted, now 7,196,989. | ||
| Claims priority of application No. 2001-370497 (JP), filed on Dec. 04, 2001. | ||
| Prior Publication US 2007/0127337 A1, Jun. 07, 2007 | ||
| Int. Cl. G11B 7/00 (2006.01) | ||
| U.S. Cl. 369—116 [369/120] | 1 Claim |
| 1. 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.
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