Method for manufacturing long laminated polarizing plate and long laminated polarizing plate

Patent metadata

Field	Value
Publication number	US-9623441-B2
Application number	US-201213883904-A
Country	US
Kind code	B2
Filing date	Aug 17, 2012
Priority date	Oct 27, 2011
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

It is an object of the invention to provide a method for manufacturing a long laminated polarizing plate having a long polarizing coating formed by coating directly on a long retardation film and to provide such a long laminated polarizing plate. The present invention relates to a method for manufacturing a long laminated polarizing plate comprising a long retardation film having a slow axis in its longitudinal direction and a long polarizing coating placed on the retardation film and having an absorption axis or a transmission axis in an in-plane direction at an angle of 25 to 65° to the slow axis direction of the long retardation film.

First claim

The invention claimed is:

1. A method for manufacturing a long laminated polarizing plate comprising a long retardation film having a slow axis in its longitudinal direction and a long polarizing coating placed on the retardation film and having an absorption axis or a transmission axis in an in-plane direction at an angle of 25 to 65° to the slow axis direction of the long retardation film,
the method comprising the steps:
(A) preparing a long retardation film having a slow axis in its longitudinal direction and having an Nz coefficient of 1.5 or less, wherein the Nz coefficient is expressed by the formula (nx−nz)/(nx−ny), wherein nx is a maximum in-plane refractive index of the film, ny is an in-plane refractive index of the film in a direction perpendicular to the direction in which nx is obtained, and nz is a refractive index of the film in its thickness direction;
(B) rubbing the long retardation film, which is obtained in the step (A), in an in-plane rubbing direction at an angle of 20 to 70° to the longitudinal direction while feeding the long retardation film; and
(C) coating the rubbed surface of the long retardation film obtained in the step (B) with a liquid crystal compound solution in an isotropic phase state, and solidifying the liquid crystal compound solution to form a long polarizing coating in which the liquid crystal compound is oriented such that an absorption axis or a transmission axis of the long laminated polarizing plate is deviated by an angle of about 0°±5° from the in-plane rubbing direction.

2. The method according to claim 1 , wherein the liquid crystal compound solution in an isotropic phase state is a lyotropic liquid crystal compound solution diluted to a concentration lower than an isotropic-phase-to-liquid-crystalline-phase transition concentration.

3. The method according to claim 2 , wherein the rubbing in the step (B) is performed by bringing a rotating rubbing roller into contact with the long retardation film being fed.

4. The method according to claim 2 , wherein the lyotropic liquid crystal compound is an azo compound having the following general formula (1):

wherein Q 1 is an aryl group; Q 2 is an arylene group; R is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an acetyl group, a benzoyl group, or a phenyl group; and M is a counter ion.

5. The method according to claim 4 , wherein M is a counter ion selected from the group consisting of a hydrogen atom, an alkali metal atom, an alkali earth metal atom, a metal ion, and a substituted or unsubstituted ammonium ion thereof.

6. The method according to claim 2 , wherein the lyotropic liquid crystal compound is an azo compound having the following general formula (2):

wherein X is a hydrogen atom, a halogen atom, a nitro group, a cyano group, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a SO 3 M group; R is a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an acetyl group, a benzoyl group, or a phenyl group; and M is a counter ion.

7. The method according to claim 6 , wherein M is a counter ion selected from the group consisting of a hydrogen atom, an alkali metal atom, an alkali earth metal atom, a metal ion, and a substituted or unsubstituted ammonium ion thereof.

8. The method according to claim 1 , wherein the rubbing in the step (B) is performed by bringing a rotating rubbing roller into contact with the long retardation film being fed.

9. The method according to claim 1 , wherein the Nz coefficient of the long retardation film is less than 1.0.

10. The method according to claim 9 , wherein the Nz coefficient of the long retardation film is from 0 to 0.5.

11. The method according to claim 1 , wherein the long retardation film is prepared to have an Nz coefficient from 0.4 to 1.0 in the step (A).

Assignees

• Matsuda Shoichi
• Asanoi Yoshiaki
• Kameyama Tadayuki
• Nitto Denko Corp

Inventors

• Matsuda Shoichi
• Asanoi Yoshiaki
• Kameyama Tadayuki

Classifications

• G02B5/305

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

• G02B5/30

  Polarising elements (light-modulating devices with active elements G02F1/00) · CPC title

• B05D5/06 Primary

  to obtain multicolour or other optical effects (B05D5/02 takes precedence) · CPC title

• B05D3/12

  by mechanical means · CPC title

• G02B5/3016 Primary

  involving passive liquid crystal elements (optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528) · CPC title