(12) United States Patent ao) Patent No.: us 6,574,045 B2
Hebrink et al. (45) Date of Patent: Jun. 3,2003
(54) OPTICAL BODIES MADE WITH A BIREFRINGENT POLYMER
(75) Inventors: Timothy J. Hebrink, Oakdale, MN
(US); Peter D. Condo, Lake Elmo, MN
(US); William W. Merrill, White Bear
Lake, MN (US)
(73) Assignee: 3M Innovative Properties Company,
St. Paul, MN (US)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 10/062,327
(22) Filed: Jan. 31, 2002
(65) Prior Publication Data
US 2002/0122252 Al Sep. 5, 2002
Related U.S. Application Data
(62) Division of application No. 09/416,462, filed on Oct. 12, 1999, now Pat. No. 6,449,093.
(51) Int. CI.7 G02B 27/28; G02B 5/30
(52) U.S. C I 359/498
(58) Field of Search 359/498, 497,
359/494, 500; 156/102; 428/212
(56) References Cited
U.S. PATENT DOCUMENTS
A optical body has at least two polymeric materials forming a reflective interface for at least one polarization of light. One optical body is a multilayer optical film that includes birefringent first optical layers and second optical layers interleaved with the first optical layers. Each first optical layer is formed using a polymer, such as a copolymer of polyethylene naphthalate. The second optical layers are formed so that they have a lower in-plane birefringence than the first optical layers for 632.8 nm light. Optical bodies can be used as, for example, polarizers and mirrors. The optical bodies can be formed using polymers that provide better index matching and are more easily protected from UV light without coloring the optical body.
16 Claims, 4 Drawing Sheets