Intrinsic polarizer

• US 20090135482A1
• Filed: 12/19/2008
• Published: 05/28/2009
• Est. Priority Date: 08/03/2004
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Mack, Jonathan M., Ralli, Philip J., Nkwantah, Gerald N., Nagarkar, Pradnya V., Gerlach, Michael K.
• Granted Patent: US 7,643,211 B2
• Time in Patent Office: Days
• US Class Current: 359/490
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid

Abstract

An intrinsic polarizer, including a sheet of PVA-type matrix that includes vinylene polymer blocks, the sheet defining a pass polarization axis and a block polarization axis perpendicular to the pass polarization axis, light having an electrical vector parallel to the pass polarization axis being substantially transmitted through the sheet and light having an electrical vector parallel to the block polarization axis being substantially absorbed by the vinylene blocks, the sheet exhibiting a dichroic ratio of more than 100.

Claims

1. An intrinsic polarizer, comprising:

a sheet of PVA-type matrix including vinylene polymer blocks, the sheet defining a pass polarization axis and a block polarization axis perpendicular to the pass polarization axis, light having an electrical vector parallel to the pass polarization axis being substantially transmitted through the sheet and light having an electrical vector parallel to the block polarization axis being substantially absorbed by the vinylene blocks, the sheet exhibiting a dichroic ratio of more than 100.

2. The polarizer according to claim 1, wherein the dichroic ratio is more than 110.

3. The polarizer according to claim 1, wherein the average light transmission for unpolarized light, Kv, through the sheet is greater than 42%.

4. The polarizer according to claim 3, wherein Kv has a value greater than 43%.

5. The polarizer according to claim 1, wherein the sheet exhibits a ratio, R, having a value of less than 2, where R is a ratio of absorbance for light at 50 nm polarized parallel to the block polarization axis over absorbance for light at 400 nm polarized parallel to the block polarization axis.

6. The polarizer according to claim 5, wherein R has a value of less than 1.7.

7. The polarizer according to claim 1, wherein the sheet exhibits a polarization efficiency in excess of 99%.

8. The polarizer according to claim 7, wherein the polarization efficiency ratio is greater than 99.5%.

9. The polarizer according to claim 8, wherein the polarization efficiency ratio is greater than 99.8%.

10. The polarizer according to claim 1, wherein the sheet exhibits an intrinsic absorption spectrum such that, when cross with an identical sheet and illuminated with a cold cathode fluorescent tube (CCFT) light source, the sheet transmits light having an a* co-ordinate with a magnitude of less than 2 and a b* co-ordinate with a magnitude of less than 2.