# US 9,039,860 B2 · Method of manufacturing polarizing plate

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- Number: US 9,039,860 B2
- Document ID: US9039860B2
- Status: Granted
- Kind: B2
- Application number: 13/581,913
- Filed: 2012-01-30
- Published: 2013-08-01
- Granted: 2015-05-26
- Earliest claimed: 2012-01-30
- Assignees: Sumitomo Chemical Company, Limited
- Applicants: Yuichiro Kunai
- Inventors: Yuichiro Kunai
- Web page: https://patentgrep.com/patent/US9039860B2

## CPC

- G02B 5/30: Polarising elements (light-modulating devices with active elements G02F1/00)
- 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)}
- G02B 5/3033: {in the form of a thin sheet or foil, e.g. Polaroid}
- G02F 1/133528: {Polarisers}
- Y10T 156/1052: with cutting, punching, tearing or severing
- Y10T 156/1062: Prior to assembly
- Y10T 156/108: Flash, trim or excess removal
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The present invention is directed to a method of manufacturing a polarizing plate having a polarizer layer and a protection film, sequentially having a drawing step of uniaxially drawing a stack film constituted of a base film and a polyvinyl alcohol based resin layer, a removal step prior to bonding of removing by cutting, opposing first end portions in a direction of width after dyeing and cross-linking the resin layer of the stack film, and a bonding step of bonding a protection film on a surface opposite to a surface on a side of the base film of the polarizer layer in the stack film from which the first end portions were removed.

## Claims

### Claim 1

A method of manufacturing a polarizing plate having a polarizer layer and a protection film, the method comprising in this order:
a stacking step of obtaining a stack film by forming a polyvinyl alcohol based resin layer on at least one surface of a base film;
a drawing step of uniaxially drawing said stack film;
a dyeing step of dyeing said polyvinyl alcohol based resin layer of uniaxially drawn said stack film with a dichromatic dye;
a cross-linking step of forming a polarizer layer by immersing said polyvinyl alcohol based resin layer of dyed said stack film in a solution containing a cross-linker for cross-linking;
a removal-prior-to-bonding step of cutting and removing, from said stack film having been cross-linked, its both first end portions located on opposite sides across its width; and
a bonding step of bonding a protection film to a surface of said polarizer layer in said stack film from which the first end portions have been removed, the surface being opposite from the base film; wherein
in said stacking step, a third end portion where said polyvinyl alcohol based resin layer is not formed is provided at both end portions located on opposite sides across the width of said base film; wherein
the third end portion is provided in a region inside by not shorter than 0.5 cm and not longer than 20 cm from each of the both end portions located on opposite sides across the width of the base film.

### Claim 2 (depends on 1)

The method according to claim 1, comprising a removal-prior-to-dyeing step of cutting and removing, from said stack film, its both second end portions located on opposite sides across its width, after said stacking step and before said dyeing step.

### Claim 3 (depends on 1)

The method according to claim 1, comprising a drying step of drying said polarizer layer after said cross-linking step and before said removal-prior-to-bonding step.

### Claim 4 (depends on 1)

The method according to claim 1, comprising a drying step of drying said polarizer layer after said removal-prior-to-bonding step and before said bonding step.