| US 7,530,721 B2 | ||
| Double-sided turning film | ||
| Xiang-Dong Mi, Rochester, N.Y. (US); Richard D. Bomba, Rochester, N.Y. (US); Robert P. Bourdelais, Pittsford, N.Y. (US); Michael L. Ferranti, Holley, N.Y. (US); Jehuda Greener, Rochester, N.Y. (US); Louis P. Harasta, Jr., Webster, N.Y. (US); Herong Lei, Webster, N.Y. (US); Stephen C. Meissner, West Henrietta, N.Y. (US); Steven J. Neerbasch, Rochester, N.Y. (US); Robert L. Walton, Fairport, N.Y. (US); John M. Palmeri, Hamlin, N.Y. (US); and Tomohiro Ishikawa, Evanston, Ill. (US) | ||
| Assigned to SKC Haas Display Films Co., Ltd., Choongchungnamdo (Korea, Republic of) | ||
| Filed on Apr. 18, 2007, as Appl. No. 11/736,735. | ||
| Prior Publication US 2008/0259634 A1, Oct. 23, 2008 | ||
| Int. Cl. F21V 7/04 (2006.01) | ||
| U.S. Cl. 362—606 [362/607; 362/618; 362/619; 362/620; 362/622; 362/624; 362/625; 362/626; 362/627] | 23 Claims |
| 1. A backlight device for display comprising (1) a side-lit light source, (2) a light guide plate, and (3) a turning film
comprising melt-extrudable and thermo-formable polymeric material, the turning film comprising prismatic structures on the
light entry surface of the film and lenticular elements on the light exit surface of the film, wherein:
(a) the prismatic structures are characterized by an average apex angle (α+β) and an average pitch (Q);
(b) the lenticular elements are characterized by an average pitch (P) and an average radius of curvature (R); and
(c) the prismatic structures and lenticular elements are out of registration by an average amount (X), and
(d) the film has average thickness (T);
provided that said averages are selected to provide a peak output angle of ±10° from normal to the light exit surface of the
light guide plate and an optical gain of at least 1.25; and wherein the turning film value derived from the formula
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