This article is a major update to similar article from 2008. While the same three digital projector technologies are still being used today, as they were in 2008, each technology has evolved to provide improved performance and support new capabilities, such a 3D. This “Overview” section attempts to present a summary of the state of each digital projection technology as well as provide examples of projectors that employ each technology. The next section provides a more detailed, more technical, discussion of the three digital projection technologies as well pointing out the areas in which each technology excels and where each has performance limitations. The final two sections discuss projector placement considerations and a observations related to a few specific projector performance factors.
This article covers projectors used for business, education and home theater applications, with a emphasis on the latter category, and the underlying digital imaging technologies being used. These digital imaging technologies include Digital Light Processing (DLP), Liquid Crystal Display (LCD), and Liquid Crystal on Silicon (LCoS). The following provides a high level overview of each of these technologies and provides examples of projectors using each of these technologies. More detailed information for each of these projection technologies is provided later in this article.
I would like to offer a few observations as to certain features now available, or soon to become available, on digital projectors that may influence you future decision for a projector purchase. Such features not unique, or need not be unique, to DLP, LCD or LCoS digital projection technology:
Dynamic irises first came into general use with LCD projectors as a means for improving on these projector’s relatively low native on/off contrast ratio and elevated black levels. Dynamic irises can now be found in many home theater projectors using DLP, LCoS and 3LCD digital display technologies including those with a relatively good native contrast ratio and low black levels. One notable exception is JVC who, with their industry leading native on/off contrast ratios of up to 100,000+, have avoided use of dynamic irises in their D-ILA (LCoS) projectors.
A more recent development is dynamic control of the projector’s lamp to facilitate increase light output in 3D mode. Sony is now using this technique within certain of their SXRD (LCoS) projectors. This feature may show up in other projectors in the future.
The migration from lamps to solid state light sources (i.e., LEDs and Lasers) has become widespread with the small portable projector’s use of LED light sources.