There are several unique benefits that are derived from DLP technology. One of the most obvious is package size. Since the DLP light engine consists of a single chip rather than three LCD panels, DLP projectors tend to be more compact. All of the current 3-pound mini-projectors on the market are DLPs. Most LCD projectors are six pounds and up.

Another DLP advantage is that it can produce smooth, high contrast video. DLP has been well-received in the home theatre world primarily due to two video quality advantages—better contrast and the lack of pixelation. Earlier generations of LCD projectors were notorious for their inability to generate acceptable black levels and contrast, and to resolve subtle shadow details. Blacks on LCDs looked grey and shadows appeared muddy and indistinct. In comparison, DLP projectors did a much better job.

While both technologies have produced improvements in contrast in the past year, DLP projectors still tend to outperform LCDs in this regard. However the practical performance advantage in black levels and contrast that DLP holds over LCD has been reduced somewhat. Toshiba’s TLP-X4100U LCD projector has a contrast rated at 800:1. Meanwhile, the latest DLP products geared toward home theatre are rated has high as 1800:1. However, one should not place too much emphasis on the specs. In reality, though the difference between projectors rated at 400:1 vs. 800:1 is quite noticeable, the difference is not so dramatic between products rated at 900:1 vs. 1800:1. Once you get to contrast ranges of 900:1 or higher, blacks appear as solid black and shadow details resolve quite nicely. Increased contrast can yield relatively subtle improvements, but there are other factors which contribute to image quality that become equally if not more important.

Reduced pixelation is another benefit of DLP. LCDs were always known for their visible pixel structure, often referred to as the screendoor effect because it appears as though the picture is being viewed through a screendoor. Historically, LCD technology has had a hard time being taken seriously among many home theatre enthusiasts (quite understandably) because of this flaw in the image.

DLP technology went a long way toward eliminating the screendoor effect. In SVGA (800x600) resolution, DLP projectors have either a muted pixel structure or an invisible pixel structure depending upon the size of the projected image relative to the viewing distance (the larger the image the more visible the pixels). Conversely, SVGA-resolution LCD projectors uniformly have a clearly visible pixel grid at just about any screen image size. For this reason, we don't recommend SVGA-resolution LCD projectors for home theatre use except for those on the most limited of budgets.

Three developments have served to close the gap between DLP and LCD in the area of pixel visibility. First was the step up to XGA resolution (1,024x768). This higher resolution uses 64% more pixels to paint the image on the screen, as compared to an SVGA-resolution projector. The inter-pixel gaps are reduced in XGA resolution, so pixels are more dense and less visible. In XGA resolution, DLP projectors have an invisible pixel grid on any typical home theater screen no matter how big. LCD projectors with standard XGA panels still have a visible, but much reduced screendoor effect.

Second, the inter-pixel gaps on all LCD machines, no matter what resolution, are reduced compared to what they use to be. So even the inexpensive SVGA-resolution LCD projectors have less screendoor effect than they used to.

The third development in LCDs was the use of Micro-Lens Array (MLA) to boost the efficiency of light transmission through XGA-resolution LCD panels. Some XGA-class LCD projectors have this feature, but most do not. For those that do, MLA has the happy side effect of reducing pixel visibility a little bit as compared to an XGA LCD projector without MLA. On some projectors with this feature, the pixel grid can also be softened by placing the focus just a slight hair off perfect, a practice recommended for the display of quality video. This makes the pixels slightly indistinct without any noticeable compromise in video image sharpness. So visible pixel structure is diminished to the point where it almost as good as DLP, but not quite.