US 7,466,382 B2Granted

Optical film and image display

AssigneeNitto Denko Corporation

InventorsShuuji Yano, Ryouji Kinoshita, Masayuki Kawai

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Abstract

An optical film(3) of the invention comprises a polarizing plate(1) and plural retardation films(2) so that an absorption axis of the polarizing plate(1) is perpendicular or parallel to slow axes of the plural retardation films(2) and the slow axes of the plural retardation films(2) are parallel to one another. An Nz value expressed by Nz=(nx1−nz1)/(nx1−ny1) is in the range of from 0.15 to 0.85 and an in-plane retardation Re1 expressed by Re1=(nx1−ny1)×d1 is in the range of from 200 to 350 nm, where in each of the plural retardation films, a direction along with the refractive index in the film plane is maximum is defined as the X-axis, a direction perpendicular to the X-axis as the Y-axis, the thickness direction of the film as the Z-axis, and where refractive indices in each axial direction are defined as nx1, ny1, and nz1, respectively, and the thickness of the film as d1 (nm). The optical film may realize an easily viewable display with high contrast ratio in a wide range.

Claims24

Dependent claims

A liquid crystal display in IPS mode,

wherein an optical film is arranged on a cell substrate on a viewing side,
a polarizing plate comprising a transparent protective film laminated on both sides of a polarizer is arranged on a cell substrate opposite to the viewing side, and
an extraordinary refractive index direction of a liquid crystalline substance in a liquid crystal cell and an absorption axis of the polarizing plate are parallel, in a state where voltage is not applied,
wherein the optical film is a laminate in which plural retardation films are laminated on one side of a polarizing plate obtained by laminating a transparent protective film on both sides of a polarizer so that a retardation film (a) and a retardation film (b) are laminated in this order from the polarizing plate side so that the slow axes of the plural retardation films are parallel to one another and the absorption axis of the polarizing plate is parallel to the slow axes of the two retardation films,
an Nz value expressed by Nz=(nx1−nz1)/(nx1−ny1) is in the range of from 0.72 to 0.78 for the retardation film (a) and in the range of from 0.22 to 0.28 for retardation film (b), and
an in-plane retardation Re1 expressed by Re1=(nx1−ny1)×d1 is in the range of from 200 to 350 nm,
where in each of the plural retardation films, a direction along with the refractive index in the film plane is maximum is defined as the X-axis, a direction perpendicular to the X-axis as the Y-axis, the thickness direction of the film as the Z-axis, and where refractive indices in each axial direction are defined as nx1, ny1, and nz1, respectively, and the thickness of the film as d1 (nm),
wherein
the transparent protective film laminated on at least one side of the polarizing plate comprises a thermoplastic resin (A) having a substituted and/or non-substituted imide group in a side chain and a thermoplastic resin (B) having substituted and/or non-substituted phenyl group, and nitrile group in a side chain;
and
wherein
an in-plane retardation expressed by Re2=(nx2−ny2)×d2 is 20 nm or less, and
a thickness direction retardation expressed by Rth={(nx2+ny2)/2−nz2}×d2 is 30 nm or less,
where in the transparent protective film laminated on at least one side of the polarizing plate, a direction along with the refractive index in the film plane is maximum is defined as the X-axis, a direction perpendicular to the X-axis as the Y-axis, the thickness direction of the film as the Z-axis, and where refractive indices in each axial direction are defined as nx2, ny2, and nz2, respectively, and the thickness of the film as d2 (nm),
and wherein the optical film is arranged so that the retardation films are laminated on the liquid crystal cell-side of the polarizing plate.

12 more elements

A liquid crystal display in IPS mode,

wherein a polarizing plate comprising a transparent protective film laminated on both sides of a polarizer is arranged on a cell substrate on a viewing side,
an optical film is arranged on a cell substrate opposite to the viewing side, and
an extraordinary refractive index direction of a liquid crystalline substance in a liquid crystal cell and an absorption axis of the optical film are perpendicular, in a state where voltage is not applied,
wherein the optical film is a laminate in which plural retardation films are laminated on one side of a polarizing plate obtained by laminating a transparent protective film on both sides of a polarizer so that a retardation film (a) and a retardation film (b) are laminated in this order from the polarizing plate side so that the slow axes of the plural retardation films are parallel to one another and the absorption axis of the polarizing plate is parallel to the slow axes of the two retardation films,
an Nz value expressed by Nz=(nx1−nz1)/(nx1−ny1) is in the range of from 0.72 to 0.78 for the retardation film (a) and in the range of from 0.22 to 0.28 for retardation film (b), and
an in-plane retardation Re1 expressed by Re1=(nx1−ny1)×d1 is in the range of from 200 to 350 nm,
where in each of the plural retardation films, a direction along with the refractive index in the film plane is maximum is defined as the X-axis, a direction perpendicular to the X-axis as the Y-axis, the thickness direction of the film as the Z-axis. and where refractive indices in each axial direction are defined as nx1, ny1, and nz1, respectively, and the thickness of the film as d1 (nm),
wherein
the transparent protective film laminated on at least one side of the polarizing plate comprises a thermoplastic resin (A) having a substituted and/or non-substituted imide group in a side chain and a thermoplastic resin (B) having substituted and/or non-substituted phenyl group, and nitrile group in a side chain;
and
wherein
an in-plane retardation expressed by Re2=(nx2−ny2)×d2 is 20 nm or less, and
a thickness direction retardation expressed by Rth={(nx2+ny2)/2−nz2}×d2 is 30 nm or less,
where in the transparent protective film laminated on at least one side of the polarizing plate, a direction along with the refractive index in the film plane is maximum is defined as the X-axis, a direction perpendicular to the X-axis as the Y-axis, the thickness direction of the film as the Z-axis, and where refractive indices in each axial direction are defined as nx2, ny2, and nz2 respectively, and the thickness of the film as d2 (nm),
and wherein the optical film is arranged so that the retardation films are laminated on the liquid crystal cell-side of the polarizing plate.

12 more elements

A liquid crystal display in IPS mode,

wherein an optical film is arranged on a cell substrate on a viewing side,
a polarizing plate comprising a transparent protective film laminated on both sides of a polarizer is arranged on a cell substrate opposite to the viewing side, and
an extraordinary refractive index direction of a liquid crystalline substance in a liquid crystal cell and an absorption axis of the polarizing plate are parallel, in a state where voltage is not applied,
wherein the optical film is a laminate in which the plural retardation films are laminated on one side of the polarizing plate obtained by laminating a transparent protective film on both sides of a polarizer so that a retardation film (b) and a retardation film (a) are laminated in this order from the polarizing plate side so that the slow axes of the plural retardation films are parallel to one another and the absorption axis of the polarizing plate is perpendicular to the slow axes of the two retardation films,
wherein
an Nz value expressed by Nz=(nx1−nz1)/nx1−ny1) is in the range of from 0.72 to 0.78 for the retardation film (a) and in the range of from 0.22 to 0.28 for the retardation film (b) and
an in-plane retardation Re1 expressed by Re1=(nx1−nz1)×d1 is in the range of from 200 to 350 nm,
where in each of the plural retardation films, a direction along with the refractive index in the film plane is maximum is defined as the X-axis, a direction perpendicular to the X-axis as the Y-axis, the thickness direction of the film as the Z-axis, and where refractive indices in each axial direction are defined as nx1, ny1, and nz1, respectively, and the thickness of the film as d1 (nm),
wherein
the transparent protective film laminated on at least one side of the polarizing plate comprises a thermoplastic resin (A) having a substituted and/or non-substituted imide group in a side chain and a thermoplastic resin (B) having substituted and/or non-substituted phenyl group, and nitrile group in a side chain,
wherein
an in-plane retardation expressed by Re2=(nx2−ny2)×d2 is 20 nm or less, and
a thickness direction retardation expressed by Rth={(nx2+ny2)/2−nz2}×d2 is 30 nm or less,
where in the transparent protective film laminated on at least one side of the polarizing plate, a direction along with the refractive index in the film plane is maximum is defined as the X-axis, a direction perpendicular to the X-axis as the Y-axis, the thickness direction of the film as the Z-axis, and where refractive indices in each axial direction are defined as nx2, ny2, and nz2, respectively, and the thickness of the film as d2 (nm),
and wherein the optical film is arranged so that the retardation films are laminated on the liquid crystal cell-side of the polarizing plate.

12 more elements

A liquid crystal display in IPS mode,

wherein a polarizing plate comprising a transparent protective film laminated on both sides of a polarizer is arranged on a cell substrate on a viewing side,
an optical film is arranged on a cell substrate opposite to the viewing side, and
an extraordinary refractive index direction of a liquid crystalline substance in a liquid crystal cell and an absorption axis of the optical film are perpendicular, in a state where voltage is not applied,
wherein the optical film is a laminate in which the plural retardation films are laminated on one side of the polarizing plate obtained by laminating a transparent protective film on both sides of a polarizer so that a retardation film (b) and a retardation film (a) are laminated in this order from the polarizing plate side so that the slow axes of the plural retardation films are parallel to one another and the absorption axis of the polarizing plate is perpendicular to the slow axes of the two retardation films,
wherein
an Nz value expressed by Nz=(nx1−nz1)/nx1−ny1) is in the range of from 0.72 to 0.78 for the retardation film (a) and in the range of from 0.22 to 0.28 additional for the retardation film (b) and
an in-plane retardation Re1 expressed by Re1=(nx1−ny1)×d1 is in the range of from 200 to 300 nm,
where in each of the plural retardation films, a direction along with the refractive index in the film plane is maximum is defined as the X-axis, a direction perpendicular to the X-axis as the Y-axis, the thickness direction of the film as the Z-axis, and where refractive indices in each axial direction are defined as nx1, ny1, and nz1, respectively, and the thickness of the film as d1 (nm),
wherein
the transparent protective film laminated on at least one side of the polarizing plate comprises a thermoplastic resin (A) having a substituted and/or non-substituted imide group in a side chain and a thermoplastic resin (B) having substituted and/or non-substituted phenyl group, and nitrile group in a side chain,
wherein
an in-plane retardation expressed by Re2=(nx2−ny2)×d2 is 20 nm or less, and
a thickness direction retardation expressed by Rth={(nx2+ny2)/2−nz2}×d2 is 30 nm or less,
where in the transparent protective film laminated on at least one side of the polarizing plate, a direction along with the refractive index in the film plane is maximum is defined as the X-axis, a direction perpendicular to the X-axis as the Y-axis, the thickness direction of the film as the Z-axis, and where refractive indices in each axial direction are defined as nx2, ny2, and nz2, respectively, and the thickness of the film as d2 (nm),
and wherein the optical film is arranged so that the retardation films are laminated on the liquid crystal cell-side of the polarizing plate.

12 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/572,602Filed 13 Sep 2004
Priority: JP 2003-33361025 Sep 2003
Published: US 2007/0002228 A14 Jan 2007
Granted: 16 Dec 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

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 5/305
Comprising multiple thin layers, e.g. multilayer stacks: including organic materials, e.g. polymeric layers
G02B
Optical elements, systems or apparatus

Family

US 2007/0002228 A1Pre-grant publication · published 4 Jan 2007
US 7,466,382 B2This patent

From the US filing history. Foreign family members aren’t listed.

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