Cellulose ester based quarter wave plates having normal wavelength dispersion

Patent metadata

Field	Value
Publication number	US-9964667-B2
Application number	US-201615064061-A
Country	US
Kind code	B2
Filing date	Mar 8, 2016
Priority date	Dec 17, 2013
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

The present invention pertains to an optical film for use as a quarter wave plate (QWP) having a normal wavelength dispersion curve. More specifically, this invention relates to a quarter wave plate based on cellulose ester polymer and fused ring additives.

First claim

The invention claimed is:

1. A uniaxially or biaxially stretched optical film comprising:
(a) a cellulose ester polymer; and
(b) an additive having the structure below:

wherein
DISK represents a disk-like moiety having a fused ring structure;

wherein said DISK is selected from the group consisting of:

A is each independently —COO—, —OOC—, —CO—, —CONH—, —NHCO—, —O—, or —S—;
Z is each independently an aryl, alkyl, ethoxylated alkyl, or ethoxylated aryl group having 1 to 30 carbon atoms;
Y is each independently a halogen, alkyl-, alkoxy-, or alkanoyl- group having 1 to 20 carbon atoms;
m=0, 1, 2, 3, or 4; and
n=0, 1, 2, or 3,

provided that when A is —COO—, Z is not an ethoxylated aryl group.

2. The optical film of claim 1 , wherein the cellulose ester polymer is selected from the group consisting of cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate.

3. The optical film of claim 2 , wherein the cellulose ester polymer has a degree of substitution of hydroxyl (DS OH ) ranging from 0.1 to 1.

4. The optical film of claim 2 , wherein the cellulose ester polymer has a degree of substitution of hydroxyl (DS OH ) ranging from 0.15 to 0.5.

5. The optical film of claim 2 , wherein the additive is selected from the group consisting of:

wherein
R is each independently a C 1 -C 20 alkyl or aryl group; and
k is each an integer ranging from 0 to 6.

6. The optical film of claim 1 , which is made by solution casting.

7. The optical film of claim 1 , which is made by melt extrusion.

8. A circular polarizer comprising the optical film of claim 1 and a linear polarizer.

9. 3D glasses comprising the optical film of claim 1 .

10. A quarter wave plate having a normal wavelength dispersion curve, wherein the plate comprises the optical film of claim 1 and satisfies the following equations:
R e (450)/ R e (550)>1 and
R e (650)/ R e (550)<1

wherein R e (450), R e (550), and R e (650) are in-plane retardations at the light wavelengths of 450 nm, 550 nm, and 650 nm respectively.

11. The plate of claim 10 , which has an in-plane retardation (R e ) of about 100-160 nm at the wavelength (λ) 550 nm.

12. The plate of claim 10 , which has an out-of-plane retardation (R th ) that satisfies the equation of |R th |<100 nm.

13. The plate of claim 10 , which has an in-plane retardation (R e ) of about 100-160 nm at the wavelength (λ) 550 nm and an out-of-plane retardation (R th ) that satisfies the equation of |R th |<100 nm.

14. The plate of claim 10 , wherein R e (450)/R e (550) is 1.001 to 1.1 and R e (650)/R e (550) is 0.95 to 0.999.

15. The plate of claim 10 , wherein R e (450)/R e (550) is 1.01 to 1.06 and R e (650)/R e (550) is 0.97 to 0.993.

16. The plate of claim 10 , wherein the cellulose ester polymer is selected from the group consisting of cellulose acetate (CA), cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB); the additive is 2-naphthyl benzoate; R e (450)/R e (550) is 1.01 to 1.06; and R e (650)/R e (550) is 0.97 to 0.993.

17. A circular polarizer comprising the plate of claim 10 and a linear polarizer.

18. 3D glasses comprising the plate of claim 10 .

Assignees

• Eastman Chem Co

Inventors

• Wang Bin
• Kuo Thauming
• Donelson Michael Eugene
• Mcwilliams Douglas Stephens

Classifications

• G02B1/08 Primary

  made of polarising materials · CPC title

• C08K5/01

  Hydrocarbons {(C08K5/0091 takes precedence)} · CPC title

• C08J2301/14

  Mixed esters · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• C08J2301/12

  Cellulose acetate · CPC title