| US 7,602,561 B2 | ||
| Optical head apparatus and optical information recording and reproduction apparatus | ||
| Yasuhiro Tanaka, Hyogo (Japan); Tomohiko Sasano, Osaka (Japan); Michihiro Yamagata, Osaka (Japan); and Daisuke Ogata, Hyogo (Japan) | ||
| Assigned to Panasonic Corporation, Osaka (Japan) | ||
| Filed on Jan. 05, 2007, as Appl. No. 11/620,086. | ||
| Application 11/620086 is a continuation of application No. 10/486003, filed on Jan. 19, 2005, granted, now 7,177,101. | ||
| Prior Publication US 2007/0109669 A1, May 17, 2007 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. G02B 9/04 (2006.01) | ||
| U.S. Cl. 359—793 [369/112.23] | 12 Claims |
| 1. An optical system comprising:
a collimating lens that converts a beam of light emitted from a light source into a substantially parallel beam of light;
and
an objective lens that focuses the beam of light from the collimating lens onto an information medium surface,
wherein a distance from the collimating lens to the objective lens is equal to a focal length of the collimating lens.
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