Retardation film, circularly-polarizing plate, and image-displaying device

Patent metadata

Field	Value
Publication number	US-10670773-B2
Application number	US-201615294158-A
Country	US
Kind code	B2
Filing date	Oct 14, 2016
Priority date	Apr 16, 2014
Publication date	Jun 2, 2020
Grant date	Jun 2, 2020

Abstract

The retardation film of the present invention contains a thermoplastic resin and is constituted of a single layer. A value of wavelength dispersion (R450/R550) that is a ratio of a retardation R450 at a wavelength of 450 nm and a retardation R550 at a wavelength of 550 nm is 0.70 or more and 0.85 or less; and a photoelastic coefficient is 14×10 −12 Pa −1 or less.

First claim

The invention claimed is:

1. A retardation film comprising a thermoplastic resin and composed of a single layer,
wherein the retardation film has:
a value of wavelength dispersion (R450/R550) as a ratio of an in-plane retardation R450 at a wavelength of 450 nm and an in-plane retardation R550 at a wavelength of 550 nm being 0.70 to 0.85; and
a photoelastic coefficient of 14×10 −12 Pa −1 or less,
wherein the thermoplastic resin comprises at least one bonding group of a carbonate bond and an ester bond and one or more structural units selected from the group consisting of a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2),
wherein in the thermoplastic resin, a content of an aromatic group-containing structural unit other than the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) is 5% by mass or less:

wherein in the general formula (1) and the general formula (2), each of R 1 to R 3 is independently a direct bond or an alkylene group having a carbon number of from 1 to 4, which may have a substituent, and each of R 4 to R 9 is independently hydrogen atom, an alkyl group having a carbon number of from 1 to 10, which may have a substituent, an aryl group having a carbon number of from 4 to 10, which may have a substituent, an acyl group having a carbon number of from 1 to 10, which may have a substituent, an alkoxy group having a carbon number of from 1 to 10, which may have a substituent, an aryloxy group having a carbon number of from 1 to 10, which may have a substituent, an acyloxy group having a carbon number of from 1 to 10, which may have a substituent, an amino group which may have a substituent, a vinyl group having a carbon number of from 1 to 10, which may have a substituent, an ethynyl group having a carbon number of from 1 to 10, which may have a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group, provided that at least two adjacent groups out of R 4 to R 9 may be linked to each other to form a ring and two substituents R 4 's, R 5 's, R 6 's, R 7 's, R 8 's, and R 9 's may be the same with or different from each other,
wherein the thermoplastic resin further comprises a structural unit represented by the following general formula (3):

and
wherein the retardation film has a film thickness of 10 μm to 60 μm.

2. A retardation film comprising a thermoplastic resin and composed of a single layer, wherein the retardation film has:
a value of wavelength dispersion (R450/R550) as a ratio of an in-plane retardation R450 at a wavelength of 450 nm and an in-plane retardation R550 at a wavelength of 550 nm being 0.70 to 0.92; and
a product of a photoelastic coefficient and an elastic modulus satisfying the following formula (I):
(Photoelastic coefficient [Pa −1 ]×10 12 )×(Elastic modulus [Pa]×10 −9 )≤35  (I),

wherein the thermoplastic resin comprises at least one bonding group of a carbonate bond and an ester bond and one or more structural units selected from the group consisting of a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2),
wherein in the thermoplastic resin, a content of an aromatic group-containing structural unit other than the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) is 5% by mass or less:

wherein in the general formula (1) and the general formula (2), each of R 1 to R 3 is independently a direct bond or an alkylene group having a carbon number of from 1 to 4, which may have a substituent, and each of R 4 to R 9 is independently hydrogen atom, an alkyl group having a carbon number of from 1 to 10, which may have a substituent, an aryl group having a carbon number of from 4 to 10, which may have a substituent, an acyl group having a carbon number of from 1 to 10, which may have a substituent, an alkoxy group having a carbon number of from 1 to 10, which may have a substituent, an aryloxy group having a carbon number of from 1 to 10, which may have a substituent, an acyloxy group having a carbon number of from 1 to 10, which may have a substituent, an amino group which may have a substituent, a vinyl group having a carbon number of from 1 to 10, which may have a substituent, an ethynyl group having a carbon number of from 1 to 10, which may have a substituent, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group, or a cyano group, provided that at least two adjacent groups out of R 4 to R 9 may be linked to each other to form a ring and two substituents R 4 's, R 5 's, R 6 's, R 7 's, R 8 's, and R 9 's may be the same with or different from each other,
wherein the thermoplastic resin further contains a structural unit represented by the following general formula (3):

and
wherein the retardation film has a film thickness of 10 μm to 60 μm.

3. The retardation film according to claim 1 , wherein the thermoplastic resin has a refractive index at a sodium d line (wavelength: 589 nm) of from 1.49 to 1.56.

4. The retardation film according to claim 1 , wherein the thermoplastic resin has a glass transition temperature of 120° C. to 160° C.

5. The retardation film according to claim 1 , wherein the thermoplastic resin has a saturated water absorption of 1.0% to 3.0%.

6. The retardation film according to claim 1 , wherein the thermoplastic resin comprises 1% to 40% by mass of one or more structural units selected from the group consisting of the structural units represented by the general formula (1) and the general formula (2).

7. A circularly polarizing plate comprising the retardation film according to claim 1 and a polarizer stacked on the retardation film.

8. An image display device comprising the circularly polarizing plate according to claim 7 .

9. An organic EL panel comprising the circularly polarizing plate according to claim 7 .

10. The retardation film according to claim 2 , wherein the thermoplastic resin has a refractive index at a sodium d line (wavelength: 589 nm) of from 1.49 to 1.56.

11. The retardation film according to claim 2 , wherein the thermoplastic resin has a glass transition temperature of 120° C. to 160° C.

12. The retardation film according to claim 2 , wherein the thermoplastic resin has a saturated water absorption of 1.0% to 3.0%.

13. The retardation film according to claim 2 , wherein the thermoplastic resin comprises 1% to 40% by mass of one or more structural units selected from the group consisting of the structural units represented by the general formula (1) and the general formula (2).

14. A circularly polarizing plate comprising the retardation film according to claim 2 and a polarizer stacked on the retardation film.

15. An image display device comprising the circularly polarizing plate according to claim 14 .

16. An organic EL panel comprising the circularly polarizing plate according to claim 14 .

Assignees

• Nitto Denko Corp
• Mitsubishi Chem Corp

Inventors

• Namiki Shingo
• Hirami Yuuichi
• Uehara Hisatoshi
• Hayashi Hiroyuki
• Shimizu Takashi
• Sumimura Hiroshi
• Murakami Nao

Classifications

• G02B5/3083

  Birefringent or phase retarding elements (G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001) · CPC title

• G02B5/305

  including organic materials, e.g. polymeric layers · CPC title

• Y10T428/1041

  Cross-Sectional Technologies · mapped topic

• H01L51/5281

  Electricity · mapped topic

• G02B1/08 Primary

  made of polarising materials · CPC title