US Patent 7751005 Liquid crystal display apparatus

An IPS (In Plane Switching) mode type liquid crystal display apparatus having polarizing plates on both sides of a liquid crystal cell, wherein the polarizing plate protective film used between a liquid crystal cell and polarizer on a backlight light-source side is a cellulose ester film having a thickness of 20-50 μm and a retardation value of 0 nm≦Ro≦2 nm and −5 nm≦Rt≦5 nm, and this cellulose ester film is characterized by temperature variation ΔRt(t) lying in the range 0 nm≦ΔRt(t)≦7 nm and humidity variation ΔRt(h) lying in the range 0 nm≦ΔRt(h)≦20 nm.