US 6,721,096 B2 · Polarizing beam splitter

Abstract

An optical imaging system including a wide-angle Cartesian polarizing beam splitter, light valve illumination optics having an f/#≦2.5, and at least one reflective light valve. The Cartesian polarizing beam splitter (PBS) has a structural orientation defining fixed polarization axes. The use of a Cartesian PBS allows the development of systems using curved PBS that provide higher light output and/or replace or augment other optical components. By recognizing and advantageously applying properties of wide-angle Cartesian polarizers, the present invention discloses a high-efficiency optical imaging system capable of functioning at f/#'s equal to or below f/2.5 while maintaining a contrast ratio of at least 100 to 1, or, more preferably, 150 to 1 in a projection system configuration.

Claims26

Dependent claims

A polarizing beamsplitter, comprising:

first and second prisms;
and
a multiple layer, polarization-sensitive film disposed between the first and second prisms, the polarization-sensitive film being formed from alternating first and second polymer layers, the polarization-sensitive film having a structural orientation defining x- and y-polarization axes parallel to the film and a z-axis perpendicular to the film, the first polymer layer being birefringent and having a refractive index nz substantially equal to one of nx and ny, where nx, ny and nz are the refractive indices for light having electric field components parallel to the x-axis, y-axis and z-axis respectively;
wherein light propagating through the polarizing beamsplitter is refracted away from a normal to the polarization-sensitive film on passing from one of the first and second prisms to the polarization-sensitive film.

1 more element

Dependencies are inferred from the claim text.

Facts

Application

10/295,674Filed 15 Nov 2002 · continuation

Priority

28 Oct 1997

Published

US 2003/0184864 A12 Oct 2003

Granted

13 Apr 2004

Term ends

Not estimatedThe source records don’t support an estimate.

Classification22 codes

G02B 27/149
Operating by reflection only: using crossed beamsplitting surfaces, e.g. cross-dichroic cubes or X-cubes
B29C 55/023
Of plates or sheets: using multilayered plates or sheets
B29D 11/00
Producing optical elements
B32B 27/36
Layered products comprising a layer of synthetic resin: comprising polyesters

Family

Application08/958,329Parent of this continuation-in-part · filed 28 Oct 1997

Application09/126,917Parent of this continuation-in-part · filed 31 Jul 1998

Application09/312,917Parent of this continuation · filed 17 May 1999

US 2003/0184864 A1Pre-grant publication · published 2 Oct 2003

US 6,486,997 B1Parent of this continuation

Application09/312,917Parent of this continuation-in-part

US 5,965,247 AParent of this continuation-in-part

US 6,721,096 B2This patent

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

Polarizing beam splitter

Life of this patent

Polarizing beam splitter

Life of this patent

Abstract

Claims26