Polarizing fiber, polarizer, polarizing plate, laminated optical film, and image display

• US 8,649,093 B2
• Filed: 12/03/2012
• Issued: 02/11/2014
• Est. Priority Date: 06/19/2007
• Status: Expired due to Fees

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Miyatake, Minoru, Nishimura, Akinori, Shinagawa, Masashi, Iwakawa, Yasuko
• Primary Examiner(s): Shafer, Ricky D
• Application Number:
  US13/692,696
• Publication Number:
  US 20130088778A1
• Time in Patent Office: 435 Days
• Field of Search: 359/487.02, 385/11, 385/115, 385/141, 385/146
• US Class Current: 359/487.02
• CPC Class Codes: D01D 5/36 Matrix structure; Spinnerette packs therefor
• CPC Class Codes: D01F 8/06 with at least one polyolefin as constituent
• CPC Class Codes: D01F 8/10 with at least one other macromolecular compound obtained by reactions only involving carbon-to-carbon unsaturated bonds as constituent
• CPC Class Codes: G02B 27/28 for polarising used in stereoscopes G02B30/25
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00
• CPC Class Codes: G02B 5/3025 Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state G02B5/3008, G02B5/3016 take precedence

Abstract

As the polarizing fiber of the present invention, the cross sectional form perpendicular to the longitudinal direction has a sea-island structure, and the cross sectional form is continuously made up in the longitudinal direction. A resin (sea component) that constitutes the sea region of the sea-island structure comprises a dichroic dye, and a resin (island component) that constitutes the island regions of the sea-island structure is a transparent resin. The polarizing fiber of the present invention may be used as a forming material of a polarizer, for example. By using the above polarizing fiber, a polarizer wherein unevenness of the transmittance is small and cracks are less generated may be formed.

Claims

1. A polarizing fiber having an absorption axis in a longitudinal direction thereof;

wherein

a cross sectional form perpendicular to the longitudinal direction has a sea-island structure, the cross sectional form being made up in the longitudinal direction;

a resin that constitutes a sea region of the sea-island structure comprises a dichroic dye;

a resin that constitutes island regions of the sea-island structure is a transparent resin;

the number of the island regions is 2 or more; and

a long diameter of each of the island regions is from 0.1 to 8.0 μ

m, and wherein when the refractive index of the resin that constitutes the island regions in a direction perpendicular to the longitudinal direction is represented by n_i1 and the refractive index of the resin that constitutes the sea region in the direction perpendicular to the longitudinal direction is represented by n_s1, the difference between the refractive indexes, Δ

n₁=|n_s1−

n_i1|, is 0.02 or less; and

when the refractive index of the resin that constitutes the island regions in the longitudinal direction is represented by n_i2 and the refractive index of the resin that constitutes the sea region in the longitudinal direction is represented by n_s2, the difference between the refractive indexes, Δ

n₂=|n_s2−

n_i2|, is 0.03 or more and 0.05 or less.

2. The polarizing fiber according to claim 1, wherein the resin that constitutes the sea region is polyvinyl alcohol or ethylene vinyl alcohol copolymer.

3. A polarizer in a sheet form, wherein the polarizing fiber as recited in claim 1 is arranged or laminated in parallel to the longitudinal direction thereof, and is further enveloped in a transparent isotropic material.

4. The polarizer according to claim 3, wherein when the refractive index of the isotropic material is represented by n_m and the refractive index of the resin that constitutes the sea region in the direction perpendicular to the longitudinal direction is represented by n_s1, the difference between the refractive indexes, Δ

n₃=|n_s1−

n_m|, is 0.02 or less.

5. An image display, having the polarizer as recited in claim 4.

6. A laminated optical film, having the polarizer as recited in claim 4.

7. A polarizing plate, having a transparent protective film on at least one surface of the polarizer as recited in claim 3.

8. A laminated optical film, having the polarizing plate as recited in claim 7.

9. An image display, having the polarizing plate as recited in claim 7.

10. A laminated optical film, having the polarizer as recited in claim 3.

11. An image display, having the laminated optical film as recited in claim 10.

12. An image display, having the polarizer as recited in claim 3.