US 8,709,567 B2Granted

Roll of continuous web of optical film laminate and production method therefor

AssigneeNitto Denko Corporation

InventorsTakeharu Kitagawa, Takuya Nakazono, Shusaku Goto, Minoru Miyatake, Tomohiro Mori, Takashi Kamijo

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Abstract

A method of producing a roll of a continuous web of an optical film laminate, usable in a process of laminating an optical film sheet including a polarizing film and formed to a size corresponding to that an optical panel to a surface of the optical panel being fed to a lamination position, is disclosed. The polarizing film is prepared by subjecting a laminate including a thermoplastic resin substrate and a PVA type resin layer formed on the substrate, to uniaxial 2-stage stretching to reduce a thickness of the PVA type resin layer to 10 μm or less, and causing a dichroic material to be absorbed in the PVA type resin layer. A carrier film is releasably attached to the continuous web of optical film laminate including the polarizing film, through an adhesive layer. A defect inspection is performed for the optical film laminate and the adhesive layer.

Claims32

Dependent claims

A roll of a carrier film-attached optical film laminate, usable in a process of continuously feeding a rectangular-shaped optical panel having a short side and a long side to a lamination position, and laminating an optical film sheet including at least a polarizing film and formed to a size corresponding to dimensions of the long and short sides, to one of two surfaces of the optical panel fed to the lamination position, wherein the carrier film-attached optical film laminate comprises:

(a) a continuous web of an optical film laminate including at least a polarizing film formed to have optical characteristics satisfying the following conditions:
P>−(100.929T−42.4−1)×100 (where T<42.3);
and P≧99.9 (where T≧42.3), wherein T is a single layer transmittance, and P is a polarization rate;
and (b) a carrier film releasably attached to the optical film laminate through an adhesive layer under a condition that an adhesion force of the carrier film with respect to the adhesive layer is weaker than an adhesion force between the optical film laminate and the adhesive layer, to form a carrier film-attached optical film laminate, and wherein (c) the carrier film-attached optical film laminate is subjected to a defect inspection for the optical film laminate and the adhesive layer, and wherein (d) a plurality of slits are formed in the carrier film-attached optical film laminate in a width direction perpendicular to the lengthwise direction, at lengthwise given intervals corresponding to one of the long and short sides of the optical panel, to extend from a surface of the optical film laminate to a depth reaching a surface of the carrier film facing the adhesive layer to thereby form an optical film laminate sheet between lengthwisely adjacent two of the slits, so that the carrier film-attached optical film laminate is formed as a continuous long sheet laminate having a structure in which a plurality of the sheets are continuously supported on the carrier film, and wherein:
(e) when one of the plurality of optical film laminate sheets includes a defect detected by the defect inspection, an identification for identifying the sheet including the defect as a defective sheet is provided to the sheet including the defect;
and (f) the continuous long sheet laminate with the identification is wound into the roll.

3 more elements

(a) a continuous web of an optical film laminate including at least a polarizing film formed to have optical characteristics satisfying the following conditions:
P>−(100.929T−42.4−1)×100 (where T<42.3);
and P≧99.9 (where T≧42.3), wherein T is a single layer transmittance, and P is a polarization rate;
and (b) a carrier film releasably attached to the optical film laminate through an adhesive layer under a condition that an adhesion force of the carrier film with respect to the adhesive layer is weaker than an adhesion force between the optical film laminate and the adhesive layer, to form a carrier film-attached optical film laminate, and wherein:
(c) the carrier film-attached optical film laminate is subjected to a defect inspection for the optical film laminate and the adhesive layer:
and (d) a plurality of slits are formed in the carrier film-attached optical film laminate in a width direction perpendicular to the lengthwise direction, at lengthwise given intervals set for a defect-free region of the carrier film-attached optical film laminate, correspondingly to one of the long and short sides of the optical panel, to extend from a surface of the optical film laminate to a depth reaching a surface of the carrier film facing the adhesive layer to thereby form an optical film laminate sheet between lengthwisely adjacent two of the slits, so that the carrier film-attached optical film laminate is formed as a continuous long sheet laminate having a structure in which a plurality of the sheets are continuously supported on the carrier film, and wherein (e) in a region of the carrier film-attached optical film laminate including a defect, a distance between lengthwisely adjacent two of the slits is set to become less than the lengthwise given interval, to allow an optical film laminate sheet formed between the lengthwisely adjacent two slits in the region including the defect to be identified as a defective sheet, and wherein (f) the continuous long sheet laminate is wound into the roll.

3 more elements

A method of producing a roll of a continuous web of an optical film laminate, the roll being usable in a process of continuously feeding a rectangular-shaped optical panel having a short side and a long side to a lamination position, and laminating an optical film sheet including at least a polarizing film and formed to a size corresponding to dimensions of the long and short sides, to one of two surfaces of the optical panel fed to the lamination position, the method comprising steps of:

(a) forming a continuous web of an optical film laminate including at least a polarizing film which consists of a polyvinyl alcohol type resin layer and has a thickness of 10 μm or less and an absorption axis in a lengthwise direction of the optical film laminate, the polarizing film being formed by performing a stretching sub-step of subjecting a laminate comprising a continuous web of a thermoplastic resin substrate and a polyvinyl alcohol type resin layer formed on the substrate, to a uniaxial stretching in a lengthwise direction of the laminate to attain a stretching ratio of 5.0 to 8.5 to thereby reduce a thickness of the polyvinyl alcohol type resin layer to 10 μm or less, and an absorption sub-step of causing a dichroic material to be absorbed in the polyvinyl alcohol type resin layer, so as to have optical characteristics satisfying the following conditions:
P>−(100.929T−42.4−1)×100 (where T<42.3);
and P≧99.9 (where T≧42.3), wherein T is a single layer transmittance, and P is a polarization rate;
(b) releasably attaching a carrier film to the optical film laminate through an adhesive layer under a condition that an adhesion force of the carrier film with respect to the adhesive layer is weaker than an adhesion force between the optical film laminate and the adhesive layer, to form a carrier film-attached optical film laminate;
(c) performing a defect inspection for the optical film laminate and the adhesive layer, and, when a defect is detected therein, recording defect information about at least a position of the detected defect;
(d) forming a plurality of slits in the carrier film-attached optical film laminate in a width direction perpendicular to the lengthwise direction, at lengthwise given intervals corresponding to one of the long and short sides of the optical panel, to extend from a surface of the optical film laminate to a depth reaching a surface of the carrier film facing the adhesive layer to thereby form an optical film laminate sheet between lengthwisely adjacent two of the slits, so that the carrier film-attached optical film laminate is formed as a continuous long sheet laminate having a structure in which a plurality of the sheets are continuously supported on the carrier film;
(e) when it is determined based on the defect information that the plurality of optical film laminate sheets include the defect detected by the defect inspection, providing an identification for identifying one of the sheets including the defect as a defective sheet, to the sheet including the defect;
and
(f) winding the continuous long sheet laminate into a roll.

6 more elements

(a) forming a continuous web of an optical film laminate including at least a polarizing film which consists of a polyvinyl alcohol type resin layer and has a thickness of 10 μm or less and an absorption axis in a lengthwise direction of the optical film laminate, the polarizing film being formed by performing a stretching sub-step of subjecting a laminate comprising a continuous web of a thermoplastic resin substrate and a polyvinyl alcohol type resin layer formed on the substrate, to a uniaxial stretching in a lengthwise direction of the laminate to attain a stretching ratio of 5.0 to 8.5 to thereby reduce a thickness of the polyvinyl alcohol type resin layer to 10 μm or less, and an absorption sub-step of causing a dichroic material to be absorbed in the polyvinyl alcohol type resin layer, so as to have optical characteristics satisfying the following conditions:
P>−(100.929T−42.4−1)×100 (where T<42.3);
and P≧99.9 (where T≧42.3), wherein T is a single layer transmittance, and P is a polarization rate;
(b) releasably attaching a carrier film to the optical film laminate through an adhesive layer under a condition that an adhesion force of the carrier film with respect to the adhesive layer is weaker than an adhesion force between the optical film laminate and the adhesive layer, to form a carrier film-attached optical film laminate;
(c) performing a defect inspection for the optical film laminate and the adhesive layer, and, when a defect is detected therein, recording defect information about at least a position of the detected defect;
(d) forming a plurality of slits in the carrier film-attached optical film laminate in a width direction perpendicular to the lengthwise direction, at lengthwise given intervals corresponding to one of the long and short sides of the optical panel, to extend from a surface of the optical film laminate to a depth reaching a surface of the carrier film facing the adhesive layer to thereby form an optical film laminate sheet between lengthwisely adjacent two of the slits, so that the carrier film-attached optical film laminate is formed as a continuous long sheet laminate having a structure in which a plurality of the sheets are continuously supported on the carrier film;
(e) when the slits are formed at the lengthwise given intervals, and it is determined that the defect detected by the defect inspection is located within the lengthwise given interval as measured from a specific one of the slits, forming a subsequent slit immediately following the specific slit, at a position spaced apart from a trailing edge of the defect in a feed direction of the carrier film-attached optical film laminate by a given distance, wherein:
(i) when a distance between the specific slit and the subsequent slit is less than the lengthwise given interval, an optical film laminate sheet formed between the specific slit and the subsequent slit can be identified as the defective sheet, based on a fact that a feed-directional length of the optical film laminate sheet is less than the lengthwise given interval;
and
(ii) when the distance between the specific slit and the subsequent slit is greater than the lengthwise given interval, at least one additional slit is formed between the specific slit and the subsequent slit to form at least two optical film laminate sheets between the specific slit and the subsequent slit, so that each of the at least two optical film laminate sheets can be identified as the defective sheet, based on a fact that a feed-directional length of each of the at least two optical film laminate sheets is less than the lengthwise given interval;
and
(f) winding the continuous long sheet laminate into a roll.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 13/225,128Filed 2 Sep 2011
Priority: JP 2010-1974133 Sep 2010
Published: US 2012/0058291 A18 Mar 2012
Granted: 29 Apr 2014
Term ends: Not estimatedThe source records don’t support an estimate.

Classification10 codes

G02B 5/305
Comprising multiple thin layers, e.g. multilayer stacks: including organic materials, e.g. polymeric layers
G02B 1/08
Optical elements characterised by the material of which they are made; Optical coatings for optical elements: made of polarising materials
G02B 5/3033
Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state: in the form of a thin…
G02B 27/288
For polarising: filters employing polarising elements, e.g. Lyot or Solc filters