When considering several projection system designs, one of the important characteristics is the total luminous flux the system will deliver to the projection screen. This is the main factor controlling perceived brightness to the viewer for a given screen size and gain. This luminous flux depends on a number of factors, such as lamp lumen output, reflector collection efficiency, projector architecture, light valve aperture ratio and the transmission/reflection efficiency of each optical component in the system. Many of these factors are amenable to accurate estimation prior to construction of a prototype projector. However, quantitative estimates of lamp/reflector light collection efficiency are difficult to make accurately. This paper will give an analytical approach based on étendue (optical extent) that can accurately predict lamp/reflector collection efficiency prior to the construction of a prototype projector. Collection efficiencies and projector lumen throughputs for several lamp/reflector/projector combinations will be estimated with this technique.
Virtual Reality is a new technology end-to-end, from content creation through distribution to display. The differences between VR and systems such as television, cinema or streaming video have led to the development of many new guidelines and standards that can be potentially confusing. This paper will attempt to reduce this confusion.
Abstract— The development of electronic projection systems from its earliest days in the 1930s to the present will be reviewed. Early projection systems were dominated by cathode‐ray tubes (CRTs) and mechanical scanners (Scophony). Until the invention of the Eidophor oil‐film light‐valve (LV) projector in the 1940s, there was no all‐electronic alternative to CRTs. Oil‐film LVs and CRTs dominated projection until the introduction of the first liquid‐crystal‐device (LCD) light‐amplifier system by Hughes. Today, the oil‐film LV has vanished and the CRT is vanishing. The light amplifier has morphed into several variations of liquid crystal‐on‐silicon (LCoS). Mechanical scanners are starting to be re‐introduced for laser display systems. However, transmissive LCDs, the digital micromirror device (DMD), and LCoS microdisplays dominate the projection‐display market today. In addition to discussing the projection systems themselves, certain key component technologies that have made modern projection systems possible will be discussed.
The lifetime of the TN45 effect used in single panel LCOS imagers has been demonstrated to be 20,000 hours at 2 Mlux illumination. This paper will document the test methods used to determine this lifetime. The variation in lifetime under different illumination conditions will also be discussed.
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