IPS LCD device having a wider viewing angle
AssigneeNEC LCD Technologies, Ltd.
InventorsHiroshi Nagai, Hidenori Ikeno
Life of this patent
Estimating the term…
Abstract
An in-plane-switching-mode (IPS) LCD device includes a TFT substrate and a CF substrate sandwiching therebetween an LC layer, and a pair of polarizing films sandwiching therebetween the substrates and the LC layer. Each polarizing film has a polarization layer and a protective layer An optical compensation layer having a birefringence is disposed between the light-emitting-side polarizing film and the CF substrate. The optical compensation layer has an in-plane retardation of N1 satisfying the following relationship: 83.050−0.810×D1≦N1≦−228.090−0.74D1 in the range of 0<D1≦80 μm, wherein D1 is the thickness of the protective layer of the light-incident-side polarizing film.
Claims6
An in-plane-switching-mode liquid crystal display (IPS LCD) device comprising:
- a liquid crystal (LC) layer having a first optical axis;
- first and second substrates sandwiching therebetween said LC layer, said first and second substrates being disposed on a light-emitting side and a light-incident side, respectively, of said LCD device;
- first and second polarizing films sandwiching therebetween said first and second substrates and said LC layer, said first and second polarizing films having polarization axes extending normal to each other and being disposed on the light-emitting side and the light-incident side, respectively, of said LCD device, each of said first and second polarizing films including a first protective layer, a polarization layer and a second protective layer, which are disposed consecutively as viewed from the light-incident side, each of said first and second protective layers having a retardation in a thickness direction thereof;
- and
- an optical compensation layer disposed between said first polarizing film and said first substrate, wherein:
- said optical compensation layer has a birefringence satisfying the relationship 0.0≦(ns−nz)/(ns−nf)≦0.5, where ns, nf and nz are a refractive index along an in-plane slow axis, a refractive index along an in-plane fast axis, and a refractive index along a thickness direction, respectively, of said optical compensation layer;
- an angle between said in-plane slow axis of said optical compensation layer and said first optical axis is within ±2 degrees;
- and
- said optical compensation layer has an in-plane retardation N1 (nm), and said second protective layer of said second polarizing film has a retardation Rt2:
- R
- t2
- =
- (
- npx
- 2
- +
- npy
- 2
- 2
- -
- npz
- 2
- )
- ×
- d
- 2
- in the thickness direction thereof, where npx2, npy2, npz2 and d2 are a refractive index along an in-plane slow axis, a refractive index along an in-plane fast axis, a refractive index along an orthogonal axis and a thickness, respectively, of said second protective layer of said second polarizing film;
- and
- said N1 and Rt2 satisfy therebetween the following relationship:
- 83.050−1.18Rt2≦N1≦228.090−1.08Rt2
- in a range of 0≦=Rt2≦55 nm.
Dependencies are inferred from the claim text.