The CRT has been a staple of the TV industry since its inception and is typically the most affordable type of RPTV (rear-projection television). Many people, including yours truly, still believe that a properly calibrated CRT rear- or front-projection set will ultimately provide the best image reproduction, especially with HDTV and DVD sources.

YOU CAN RESEARCH native resolution, inputs and a variety of other hard specifications, but in order to tell how well a display will reproduce its image, you have to physically see it.

Admittedly, CRT-based units are a bit temperamental if you want absolute peak performance from them, and they will require the most maintenance to keep the image as good as it can be. Things like convergence drift (where the red, green and blue images don’t line up correctly to create a single image) can occur. Although many newer RPTV models have easy user convergence or in some cases have auto-convergence (where one press of a button aligns the TV colors automatically), front projectors don’t, and few people want to converge a TV set anyway, whether it’s easy or not. Most of us just want to watch TV, not spend hours adjusting it.

The other category is digital displays: DLP, LCD and LCoS. Unlike a CRT, digital displays use a lamp that either reflects off of a microchip or shines through a panel that is creating the image. The microchip or panel is made up of a fixed grid of hundreds of thousands of individual picture elements, or pixels, that create the image. As a result, there is no convergence to mess with, and aside from replacing the lamp every 5,000 to 8,000 hours (around three to five years of average use), these units are virtually maintenance-free.

A DLP projector uses a single DMD (digital micromirror device) to create the image. This is called reflective technology, because the light is reflected off the DMD, sent through a color filter wheel, which adds color to the image, and then projected through a lens onto the screen. DLP projectors can be extremely bright.

The big upside of DLP is that it has the best contrast ratio, or the greatest difference between light and dark, of the three digital technologies. With new DMDs, which use the Mustang or HD2 chip, the blacks are much darker than either LCD or LCoS. This makes a huge difference with higher-quality signals (especially HDTV) and creates a lot of depth in the image. The downside is that single-chip DLP projectors (the only kind available in RPTV form) still must use a color wheel. While color wheels have improved immensely over the years, they sometimes create a slight rainbow effect—colored fringes on moving objects—that can prove distracting for some viewers.

An LCD projector, on the other hand, is considered transmissive because light shines through each LCD panel (or is blocked in darker parts of the image) as opposed to reflecting off of it. The upside of modern LCD displays is that they don’t require a color wheel; each color (red, green and blue) gets its own panel. LCD, however, does not produce blacks as dark as those achieved by DLP. Viewers may find this distracting, especially with higher- resolution signals.

Finally, the newcomer to the digital display world is LCoS technology. LCoS is considered reflective technology, though it uses liquid crystals like an LCD. With an LCoS unit, however, the liquid crystals are reflective. The biggest plus with an LCoS display is its high pixel count. It is the first digital display technology that has a 1920-by-1080-pixel count, meaning that most if not all high-definition signals can be displayed without any loss of resolution. It also means that the display is compatible with higher-resolution computers, so from a resolution standpoint, the LCoS technology has the greatest flexibility. But, like its LCD relative, it also has a higher black level than competing technologies, so its picture looks somewhat washed out in comparison.

What hasn’t been discussed here is the look of the images from any of the display technologies. Though each digital display’s image is made up of pixels, and the number of pixels in a display affects the detail of the image, the appearance of the image is quite different between a DLP, LCD and LCoS display. How the image looks is the result of one or more of a variety of factors, and most models of the same type of video technology tend to have a similar look. For example, LCD televisions have higher black levels and their pixels are farther apart than those of DLP or LCoS televisions, which can produce an effect akin to watching TV through a screen door. DLP televisions do not have these issues, but they do have the aforementioned rainbow effect as a result of the use of the color wheel. I’ve always said that the most important specification of any type of display is the one that cannot be described in print. You can research native resolution, inputs and a variety of other hard specifications on a spec sheet, but in order to tell how well a display will reproduce its image, you have to physically see it.

When considering a purchase, always know what inputs you need for the video sources (DVD player, satellite receiver, etc.) you own, and the size of the screen your room can accommodate. And before assuming that one type of display is better than another because of resolution, light output or any other specification, take a quick trip to your local audiovisual retailer. You may be surprised at what you see.

Related Product Directories

 Digital Rear Projection Displays
If a plasma is too expensive, but you want a space-saving display then a digital rear projection TV is the next option. The LCD, DLP and LCoS-based products in this listing have TV cabinet to be only a foot or two deep.

 CRT Rear Projection Displays
CRT techonlogy may be old-school, but it is still one of the best looking pictures you can find. This listing includes all the large-screen, rear-projection digital-ready and integrated DTVs we could find.

 Digital Front Projectors
Here’s a listing of single-lens front projectors based on LCD, DLP and LCoS technologies. These can provide a hassle-free, cinematic experience.

 CRT Front Projectors
For the absolute best picture on screen sizes up to seven feet wide, check out this list of three-gun, CRT-based front projectors.