There are two main competing technologies in digital projectors: LCD and DLP. LCD projectors transmit light through three colored panels while DLP projectors reflect light off an image chip. These technologies are fundamentally different, yet they have results that are amazingly similar. It is hard to say that one technology is better than another in all cases.
This is written so that those considering purchasing an LCD projector can understand the advantages and disadvantages of one. It is mainly to help understand more deeply the differences in the two technologies. There is another article about DLP advantages and disadvantages.
LCD Projector Advantages
The way an LCD projector works is that it allows light to pass through three colored liquid crystal display light panels. These panels block certain colors and allow others through so that the image shows up on screen. This is different than DLP technology which reflects light off of a mirrored panel through a color wheel. Many LCD projectors will say they are 3LCD machines. The truth is that all LCD projectors use three panels.
The biggest advantage of LCD over DLP is the price difference. LCD can deliver higher lumen output (amount of lamp brightness) at a lower price than DLP. An LCD projector can achieve greater brightness at a lower energy consumption. The cost difference of LCD over DLP is even greater when cost of electricity and lamp replacement is factored in.
Historically DLP projectors have delivered greater contrast ratios over LCD. But that difference is going in favor of LCD projectors today. Currently there is not much difference in what they can achieve, but LCD will overtake DLP. This higher contrast ratio comes at a cost though. While LCD can outperform DLP, those projectors that do a much better job in contrast ratio lose the advantages of being more cost efficient. Lower cost projectors will still have the advantage of contrast ratio in the favor of DLP. LCD projectors intended for home theater use are similar in contrast ratio to DLP projectors.
DLP projectors suffer from two possible artifact problems: dithering and rainbow effect. These don't always happen, but they are possible. LCD projectors have neither of these problems. When viewed side by side an LCD projected image will look more stable than a DLP image.
LCD projectors have been known for their image sharpness. This is not to say that DLP images are fuzzy, it is just that LCD is crisper. In the past this was actually a problem with LCD projectors. It is known as the screen door effect and resulted in such a sharp image that it was possible to see the individual pixels. With today's advanced resolution and LCD projector quality, the pixels are so small that it is hard to notice the screen door effect even though it still exists.
It is possible to achieve greater zoom magnification with an LCD projector. Couple a good zoom with the ability of LCD projectors to digitally adjust the image to odd throw angles and it is possible to install an LCD projector in many more places. DLP projectors need to be directly in line with the screen and not further away than their meager zoom capabilities will allow. LCD projectors are much more flexible because of their installation options.
LCD Projector Disadvantages
An LCD projector uses three panels that light passes through to create the image. Essentially the images are stacked on each other on the screen. Because there are three panels, it is possible for one to fall out of alignment. This will cause one of the three stacked images to be shifted slightly; this is called convergence. If it is minimal, then the on-screen image will be slightly fuzzy, or out of focus. It is possible that one of the panels would be enough out of alignment for all the colors to be off and there be a ghosting of the image. This would look like the Sunday comics when one of the colors is printed out of alignment with the others.
It is unknown as to how long the life span of an LCD panel is. With the harsh light and heat that the panel is subjected to, an organic LCD color panel will break down over time. The big question is, how long will it take? At this point those who may know, LCD projector manufacturers, are not telling. Texas Instruments (the owner of DLP technology) suggests that degradation takes place at much less than 4,000 hours-the life span of a single projector lamp. The problem would result in a degradation of color and brightness. This is suspected to only be a problem with organic LCDs. Inorganic light panels may not break down as much over time, but the data is not being published if anyone knows.
The light engines of LCD projectors are not sealed. This permits the possible introduction of dust particles. The way this is prevented from happening is that LCD projectors have filters on their air-intake vents. These filters need to be cleaned periodically causing an LCD projector to be more maintenance intensive. A dust spot can require professional cleaning of the projector. An even greater problem when the vents are not cleaned is that the projector can more easily overheat causing damage to the projector itself, or shorten the life of the projector lamp.
LCD Projector Wrap-up
There are approximately 50% more models of DLP projectors than there are LCD projectors on the market. However, due to the popularity of LCD projectors, it is estimated that approximately 50% of the installed base of projectors are of the LCD variety. This could simply be due to their relative price difference. Or it could be that LCD projectors are just so much more flexible that they fit in more environments.
The main takeaway from this is that both technologies are good. Both are better than they were a few years ago. It is a matter of finding out what the needs of the consumer are and buying a projector that fits those specific needs. There is no single answer to which one is best overall.
Often retailers that sell projectors will have staff on hand who can answer questions and guide the buyer into a right decision. A consumer should not hesitate to call for specific information from a projector dealer. They are usually glad to help.