| US 7,593,306 B2 | ||
| Diffraction element and optical pick-up apparatus having the same | ||
| Bong-gi Kim, Suwon-si (Korea, Republic of); Soo-han Park, Yongin-si (Korea, Republic of); and Jang-hoon Yoo, Seoul (Korea, Republic of) | ||
| Assigned to Samsung Electronics Co., Ltd., Suwon-si, Gyeonggi-do (Korea, Republic of) | ||
| Filed on Jan. 24, 2006, as Appl. No. 11/337,584. | ||
| Claims priority of application No. 2004-94452 (KR), filed on Nov. 18, 2004; and application No. 10-2005-0039404 (KR), filed on May 11, 2005. | ||
| Prior Publication US 2006/0120248 A1, Jun. 08, 2006 | ||
| Int. Cl. G11B 7/00 (2006.01) | ||
| U.S. Cl. 369—112.03 [369/109.02] | 14 Claims |
| 1. A diffraction element for an optical pick-up apparatus, comprising:
first and second regions formed in the element with a grid pattern in which the grids are repeated with a predetermined pitch
P; and
at least one of the first and second regions has a grid pattern tilted by a predetermined angle with respect to a virtual
line (VL) that is substantially perpendicular to a division line (DL) that divides the first and second regions,
wherein the grid pattern of the first region and the grid pattern of the second region are formed to be deviated from each
other such that corresponding grid patterns on opposite sides of the division line are not mirror images of one another.
|