Lengthy stretched film, and manufacturing method and use thereof

Patent metadata

Field	Value
Publication number	US-10036841-B2
Application number	US-201514663088-A
Country	US
Kind code	B2
Filing date	Mar 19, 2015
Priority date	Mar 24, 2006
Publication date	Jul 31, 2018
Grant date	Jul 31, 2018

Abstract

A lengthy stretched film made of a thermoplastic resin, having, over the width direction of at least 1300 mm, a value of an orientation angle θ to a take-up direction in a range of 40° to 50° and fluctuation thereof of 1.0° or less, and a value of an average Nz coefficient in a range of 1.3 to 2.0 and fluctuation thereof of 0.10 or less. A lengthy circularly polarizing plate constituted by laminating the lengthy stretched film with a lengthy polarizer. A reflective display type liquid crystal display device provided with the circularly polarizing plate constituted by trimming the lengthy circularly polarizing plate to a desired size.

First claim

The invention claimed is:

1. A lengthy stretched film made of a thermoplastic resin,
wherein the stretched film has a saturated water absorption of 0.03% by weight or less,
wherein over the width direction of at least 1300 mm,
a value of an orientation angle θ to a take-up direction is in a range of 40° to 50°;
fluctuation of the orientation angle θ to a take-up direction is 1.0° or less;
a value of Nz coefficient is in a range of 1.3 to 2.0; and
fluctuation of the Nz coefficient is 0.10 or less.

2. The stretched film according to claim 1 , wherein retardation Re in an in-plane direction is in a range of 100 to 300 nm over the width direction of at least 1300 mm.

3. The stretched film according to claim 1 , wherein the fluctuation of the retardation Re in an in-plane direction is within 10 nm over the width direction of at least 1300 mm.

4. The stretched film according to claim 1 , wherein an average thickness is in a range of 30 to 80 μm and thickness fluctuation is 3 μm or less over the width direction of at least 1300 mm.

5. A manufacturing method of the lengthy stretched film according to claim 1 , comprising:
a step of stretching a lengthy unstretched film made of a thermoplastic resin to obtain a first stretched film A with an orientation angle θ 1A to a take-up direction in a range of 40° to 50°; and
a step of re-stretching the first stretched film A to obtain a second stretched film A with an orientation angle θ 2A to a take-up direction in a range of θ 1A +85° to θ 1A +95°.

6. The manufacturing method of a stretched film according to claim 5 , wherein a stretching magnification R 1A in the step for obtaining the first stretched film A is 1.3 to 3.0 and the stretching magnification R 2A in the step for obtaining the second stretched film A is 1.3 to 3.0.

7. A manufacturing method of the lengthy stretched film according to claim 1 , comprising:
a step of longitudinally stretching a lengthy unstretched film made of a thermoplastic resin to obtain a first stretched film B with an orientation angle θ 1B to a take-up direction in a range of ±1° and a refractive index difference Δn in a range of 0.001 to 0.003; and
a step of tenter-stretching the first stretched film B while feeding it out so that a feeding-out angle θ 2B to a take-up direction of a second stretched film B is 15°<θ 2B <θ+5° to obtain the second stretched film B with an orientation angle θ to the take-up direction in a range of 40° to 50°.

8. The manufacturing method of the stretched film according to claim 7 , wherein a stretching magnification R 1B in the step for obtaining the first stretched film B is 1.1 to 2.0 and the stretching magnification R 2B in the step for obtaining the second stretched film B is 1.3 to 2.0.

9. A lengthy circularly polarizing plate constituted by laminating the lengthy stretched film according to claim 1 and a lengthy polarizer.

10. A liquid crystal display device comprising a stretched film obtained by trimming the lengthy stretched film according to claim 1 .

11. The liquid crystal display device according to claim 10 , further comprising a reflective display type liquid crystal panel.

12. A liquid crystal display device comprising a circularly polarizing plate obtained by trimming the lengthy circularly polarizing plate according to claim 9 .

13. The stretched film according to claim 1 , wherein the content of a residual volatile component is 0.1% by weight or less.

Assignees

• Zeon Corp

Inventors

• Asada Takeshi

Classifications

• G02F2001/133541

  Physics · mapped topic

• C08J5/18

  Manufacture of films or sheets · CPC title

• G02B5/3083 Primary

  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

• G02F1/13363

  Birefringent elements, e.g. for optical compensation · CPC title

• G02F1/133528

  Polarisers · CPC title