A new 3M Polarizing Beamsplitter (PBS) enables high performance optical engines for Liquid Crystal on Silicon (LCOS) projectors. It overcomes the limitations of previous LCOS optical engines that have insufficient light efficiency, contrast, and dark state uniformity. These limitations are the direct result of the performance of existing MacNeille PBS's: poor transmission of p-polarized light (Tp) and reduced contrast at modest beam angles and wavelength sensitivity. 3M has addressed these problems by creating a plastic polarizing film made of alternating layers of different plastics with the refractive indices tailored so that they match in one direction but not in the other. In the unmatched direction, a quarter-wave stack is formed that is highly reflective, while the matched direction appears as a transparent slab of plastic. This film is laminated between glass prisms to form a PBS with none of the problems associated with MacNeille PBS’s. For an F/2 beam, Tp exceeds 92% across the visible and photopic contrast exceeds 2000:1. High contrast is achievable in an optical engine without the use of a post-polarizer, avoiding this 15% loss that is necessary with a MacNeille PBS. Finally, the input light need not be highly polarized, allowing the engineer additional design freedom.
Several illumination calculation programs are available o aid in the design of electronic projectors. In this paper, two programs are compared: ASAP and TracePro. First, their capabilities are compared in a checklist. ASAP has enough features to model almost any optical system, while TracePro is a newcomer that is in the process of adding necessary features. TracePro excels at system entry and file transfer. Second, each of them is used to analyze tow electronic projector models: and early design wi a single 6.4 inch diagonal panel and a current design with three 1.3 inch polysilicon panels. Performance predictions by the two programs are similar, although ASAP traces rays much faster.
Conference Committee Involvement (4)
Projection Displays XII
24 January 2007 | San Jose, California, United States
Projection Displays XI
26 January 2005 | San Jose, California, United States
Projection Displays X
21 January 2004 | San Jose, California, United States