Patent ID: 7170574

Claim:
A polarization controlling device for providing a desired amount of phase delay to compensate for a predetermined amount of out of plane retardance between 0 nm and 1000 nm, single pass, in a liquid crystal (LC) display panel, which has out of plane ordinary and extraordinary indices of refraction, comprising: a substrate having a refractive index; a form birefringent multi-layer dielectric (FB) stack disposed on the substrate including a first plurality of layers having a first refractive index and a first optical thickness; and a second plurality of layers having a second refractive index and a second optical thickness, interleaved with the first plurality of layers, defining effective out of plane ordinary and extraordinary indices of refraction; and first and second anti-reflection (AR) coatings at interfaces between ambient atmosphere and the device for decreasing the amount of reflection therefrom; wherein the first and second optical thicknesses are between 1/120 and 1/16 of the center wavelength resulting in a one-dimensional grating structure forming a −C plate for compensating out of plane retardances from the LC panel and from the AR coatings; and wherein a difference between the first and second indices of refraction is greater than 0.5 for increasing the effective indices of refraction and decreasing the width of the FB stack required.