Optical compensation polarizing film achieving a higher viewing angle
AssigneeNEC LCD Technologies, Ltd.
InventorHiroshi Nagai
Life of this patent
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Abstract
An LCD device includes first and second compensation polarizing films sandwiching therebetween a homogeneously-oriented liquid crystal layer. The first compensation polarizing film includes a polarizing film having an in-plane retardation of 35 to 245 nm, wherein n1≧nz>n2, wherein n1 and n2 are refractive indexes of optical axes extending perpendicular to each other within the first retardation film and nz is a thickness-direction refractive index of the first retardation film. The second compensation polarizing film has a protection layer, a polarizing film and a retardation film having an in-plane retardation of 0 to 10 nm and thickness-direction retardation of 0 to 35 nm.
Claims7
An optical compensation polarizing film pair comprising:
- a first compensation polarizing film including a first protecting layer, a first polarizing layer, a first retardation film and a negative-uniaxial second retardation film, which are arranged in this order:
- and
- a second compensation polarizing film used in pair with said first compensation polarizing film and including a second protecting layer, a second polarizing layer, and a third retardation film, which are arranged in this order:
- said first retardation film having a birefringence wherein an in-plane retardation is 35 to 245 nm, and refractive indexes therein satisfy the following relationship:
- n1≧nz>n2, given n1 and n2 being refractive indexes of optical axes extending perpendicular to each other within said first retardation film and given nz being a thickness-direction refractive index of said first retardation film, one of said optical axes of said first retardation film having said refractive index of n1 extending normal to an absorption axis of said first polarizing layer;
- said second retardation film having a birefringence wherein an in-plane retardation is 0 to 15 nm, and a thickness-direction retardation is 50 to 123 nm, said second retardation film having an optical axis normal to a surface of said first polarizing layer;
- said third retardation film having a birefringence wherein an in-plane retardation is 0 to 10 nm and a thickness-direction retardation is 0 to 35 nm.
Dependencies are inferred from the claim text.