High durability circular polarizer for use with emissive displays

• US 6,549,335 B1
• Filed: 07/28/2000
• Issued: 04/15/2003
• Est. Priority Date: 07/28/2000
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Gordon, James N., Trapani, Giorgio, Pawlak, Richard, Carlson, Gene R.
• Primary Examiner(s): Juba, Jr., John
• Application Number:
  US09/627,257
• Time in Patent Office: 991 Days
• Field of Search: 359/490, 359/492, 359/497, 359/483, 359/485, 359/494, 353/20, 362/19, 345/32, 345/35, 345/39, 345/44, 345/45, 345/46
• US Class Current: 359/487.02
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/8791 Arrangements for improving contrast, e.g. preventing reflection of ambient light

Abstract

A high durability circular polarizer includes an unprotected K-type polarizer, such as a KE polarizer sheet, and a quarter-wavelength retarder. An optical system using the circular polarizer further includes an emissive display module such as an organic light emitting diode or a plasma display device.

Claims

1. An optical system, comprising:

an organic light emitting diode having a reflective layer for reflecting ambient light; and

a circular polarizer disposed adjacent to the organic light emitting diode, the circular polarizer comprising an unprotected K-type polarizer based on sheets or films of polyvinyl alcohol with a balanced concentration of light-absorbing chromophores, and an unsupported quarter-wavelength retarder, wherein the circular polarizer absorbs the ambient light reflected from the reflective layer of the organic light emitting diode.

2. The optical system according to claim 1 wherein the K-type polarizer comprises a KE polarizer sheet.

3. The optical system according to claim 1 wherein the K-type polarizer and the quarter-wavelength retarder are films.