The Difference Between DLP and LCD – Setting the Record Straight

If you’re new to the home theater projector market, one of the first thing you’ll notice is that DLP and LCD seem to allude to two different types of projectors.  Naturally, you’ll want to know which one is better and compare the two.

Unfortunately, it’s not that simple.  Like so much else in the digital world, the two different formats create very interesting and unique advantages over the other.  It is one of those situations where no format is technically “better” than the other but one wherein the user decides which option best fits their needs.

We don’t want to forget another prominent technology called LCOS, which stands for Liquid Crystal on Silicon, and is currently being developed by large companies such as Hitachi and JVC. It too is an incredible technology that shouldn’t be forgotten but it is far less prominent in the home theater world and will gain steam in the future.

LCD projectors usually make use of three separate LCD panels, one for red, one for green, and one for blue; together they make up a full colour stream. When the light from the bulb passes through each of the LCD panels, they can open or close individual pixels to either allow light through, or they can block it from reaching the next LCD or lens.  In doing so, a beautiful RGB image is created with literally millions of different colour combinations possible.

DLP, on the other hand, is a technology developed by Texas Instruments.  Unlike the LCD chips, no light ever passes through the DLP chip.  It is, instead, a whole bunch of tiny little mirrors that reflect light either through the lens or away from it to represent a full image.  If you are really quite rich and can afford to spend tens of thousands of dollars there are certain projectors that use 3 separate DLP chips, one for each colour in the RGB stream.  To produce colour in single DLP chip projectors, there is a colour wheel with different filters on it that defines what colour will be projected.  The light from the bulb shines through the colour wheel and as it spins, it determines which colour in the RGB scope will shine through.  The angle at which each little mirror is reflected into the lens determines the amount of colour that makes it through on any given pixel at any given time.  In doing so, the light is manipulated at every given pixel with any amount of colour from a red, blue, or green stream of colour and produces an image on the screen.

LCD chips are often better at producing colours with more accurate saturation.  This is because in the DLP colour wheel, there is normally a clear panel that is meant to increase brightness which is a huge seller for most projector buyers.  The white screen on the wheel does add brightness to the image but in doing so it also tends to wash it out a bit.  The colours don’t appear to be as saturated and beautiful as they should but they do it willingly, knowing of the payoff. Even when the colour wheel doesn’t include a white segment, the LCD projectors usually tend to have better colours and produce nicer looking images.

The resolution delivered by an LCD chip is also almost always sharper than that of a DLP chip.  You notice the difference more with text and straight defined lines, not so much with the movies and pictures, but it’s still an advantage.  You really notice it when an LCD projector is placed right next to a DLP projector, like when you did Coke and Pepsi taste tests.

LCD projectors also tend to be more efficient at thurning the light produced by the lamp directly into ANSI lumens after it has left the projection lens.  Generally speaking, the LCD projectors seem to let more light through their panels and onto their final destination than their DLP counterparts normally would. Although DLP technology has made some incredible strides in recent years, the projectors putting out the brightest images are always LCD.

On the other side of the coin for LCD projectors is the ever problematic so-called Screen Door Effect.  This little baddy produces what looks like tiny black lines outlining each and every pixel on the screen, creating what looks like a screen door on the image.  The idea is that when you take an image of a finite number of pixels, as you make each pixel bigger, you also make the space between each pixel bigger.  At regular projection screen sizes you will never notice this problem but when you get into 120″ range, you definitely risk seeing the effect.  Like a screen door though, you can really just look right through it.  My first projector was only 800×600 and I had it projecting at 120″.  Although the screen-door effect was noticeable when I first sat down, as soon as the screen had movement I forgot about it completely.

LCD technology is also said to produce an imperfect image when it comes to black levels and contrast.  LCD’s tend to wash blacks out and make them less black than they should be; something that will trouble anyone who cares enough.  It has lead to the technology not being taken seriously in home theater circles and continues to be a mark on the technology.

These problems are becoming less and less important though.  As time passes and technology improves, the problems get pushed back.  For example, my old 800×600 projector has less than half the pixels a new LCD projector does, that means that the screen door effect would only be noticeable at a size twice what I had it at.  The gaps between pixels are also smaller.  They can cram so many pixels on a single panel nowadays that it absolutely boggles the mind to see one.  And although there have been incredible improvements in black levels and contrast with LCD’s, DLP is still the technology that leads in this department.

DLP projectors tend to be much smaller than a comparative LCD projectors.  They normally only need just one chip instead of the LCD’s three making it much easier to adjust for small space accordingly. All of the mini 3-pound projectors available use DLP chips because it quite simply wouldn’t be possible with an LCD chip.

DLP technology is still much better than LCD at creating good black levels and contrast.  Both technologies have made incredible steps in the past few years but DLP technology had a huge head start.  It has managed to maintain it’s foothold and continues to price images with better blacks and contrast.

DLP does, however, have an achilles heel.  Debates as to just how much this affects picture quality are often hot topics in videophile forums but to me, the Rainbow Effect doesn’t really bother me.  The so-called “rainbow effect” is brought on by the spinning colour wheel between the lamp and the DLP chip.  Technically, it can produce a… thing… I don’t know how best to describe it. Perhaps an anomaly, that looks like the colours separating out in the red green and blue apparent in the colour wheel.  The problem arises because the whole image on screen at any given time is either red, green, blue, or white.  Your eyes normally don’t notice it because it changes so quickly but there are some tells that this is actually going on.  Some people will notice the colours break out but others have been known to suffer from eye strain and headaches.  LCD’s don’t suffer from these problems because they are constantly shooting all three colours at the screen simultaneously.

The rainbow effect for me is about as big a problem as the screen door effect was on an 800×600 LCD projector.  I noticed it a bit at first, and I had to be looking for it to notice it, but after I started watching a movie, the thought didn’t cross my mind again. People do, however, experience much worse repercussions from watching DLP projections.  I am not one of them and don’t know of anybody having these problems but to not mention it would be irresponsible.

It should also be noted that Texas Instruments did some research a while back on LCD technology that claims LCD technology will eventually cause the colours to break down and produce less contrast and a shift in colour balance.  On the other hand, Texas Intsruments’ famed DLP chip didn’t fall victim to these shortfalls.  I think it’s also very important to keep in mind that Texas Instruments owns DLP and they funded and conducted the “research”.  In any case, you can colour me skeptical.

In reality, both technologies produce incredible images at this stage of their lives.  You have to decide on your part which picture you prefer and at what cost.  Get out there and do some research of your own and see if you can find images of certain DLP projectors benchmarked against their LCD counterparts. There is no clear “better” technology but you as the consumer have more options here and can hopefully make a more informed decision based on what you have learned.

More from theaterprojector.org

• Top 20 Blu-Ray Movies to Watch on Your Home Theater Projector
• Make a Home Theater Projector With an Old LCD Monitor and an Overhead Projector
• The Vivitek H3080FD – 1080p for Peanuts.