Polarizing film, laminated film, and liquid crystal display

• US 9,494,720 B2
• Filed: 09/10/2013
• Issued: 11/15/2016
• Est. Priority Date: 08/08/2003
• Status: Expired due to Fees

• Current Assignee: Nitto Denko Corporation
• Original Assignee: Nitto Denko Corporation
• Inventors: Ishibashi, Kuniaki, Yoshimi, Hiroyuki
• Primary Examiner(s): GOFF II, JOHN L
• Application Number:
  US14/022,767
• Publication Number:
  US 20140008011A1
• Time in Patent Office: 1,162 Days
• Field of Search: 156/229, 156/324, 156/325, 156/326, 264/1.31, 264/1.34, 264/1.7, 349/96, 349/97, 349/102, 349/117, 349/118, 428/1.3, 428/1.31
• US Class Current: 1/1
• CPC Class Codes: B32B 33/00 Layered products characterised by particular properties or particular surface features, e.g. particular surface coatings; Layered products designed for particular purposes not covered by another single class
• CPC Class Codes: B32B 38/0012 Mechanical treatment, e.g. roughening, deforming, stretching
• CPC Class Codes: C09K 2323/031 Polarizer or dye
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]

Abstract

A method for producing a laminated film includes continuous roll to roll production steps of: providing a first long polymer film and having an absorption axis in the transverse direction; providing a second long polymer film and having a slow axis in the machine direction (MD direction); and laminating the polarizing film on the retardation film by adhering the polarizing film to the retardation film with an adhesive layer so that an MD direction of the first long polymer film corresponds to the MD direction of the second long polymer film.

Claims

1. A method for producing a laminated film comprising the continuous roll to roll production steps of:

providing a polarizing film comprising a first long polymer film and having an absorption axis in a TD direction of the first long polymer film, the TD direction being the transverse direction;

providing a uniaxially-stretched retardation film comprising a second long polymer film and having a slow axis in an MD direction of the second long polymer film, the MD direction being the machine direction, each of the first long polymer film and the second long polymer film having a length not smaller than 5 times as long as a width thereof; and

laminating the polarizing film on the retardation film by adhering the polarizing film to the retardation film with an adhesive layer so that an MD direction of the first long polymer film corresponds to the MD direction of the second long polymer film,

wherein the step of providing the polarizing film includes;

stretching the first long polymer film in the TD direction thereof by a biaxial stretching machine; and

dyeing the first polymer film with a dichroic substance, and

wherein in the retardation film, an angular difference between a maximum value and a minimum value of a slow axis in the lengthwise direction is 0.5 degree to 1.8 degree.

2. The method according to claim 1, wherein each of the first long polymer film and the second long polymer film has a width in the range of 5 mm to 5 m.

3. The method according to claim 1, wherein the retardation film comprises a non-liquid crystalline material.

4. The method according to claim 3, wherein the non-liquid crystalline material is selected from the group consisting of polyetherketone, polyamide, polyester, polyimide, polyamideimide, and polyesterimide.

5. The method according to claim 1, wherein the retardation film has a refractive index distribution of nx>

ny>

nz, where nx and ny are in-plane refractive indices and nz is a thickness-wise refractive index.

6. The method according to claim 1, wherein the biaxial stretching machine is a pantograph type machine.

7. The method according to claim 1, wherein the biaxial stretching machine is a spindle type machine.