DLP Projector or LCD Projector - Which works best for you
03/04/2006 -Art Feierman

This series of articles looks briefly at the technologies involved, and focuses on the practical aspects of whether a DLP or LCD projector is your best solution.

The series is broken down into the following sections:

Overview and Technology
DLP vs LCD Home Theater Projectors
DLP vs LCD Featherweight Projectors (under 5lbs.)
DLP vs LCD Portable Projectors
DLP vs LCD Fixed Installation projectors
A look at other technologies: LCOS, LED, CRT, Laser (coming soon)

The Basic Differences in Technology

LCD projectors - start with a source of light (lamp) and split the light into three beams. Each beam passes through its own LCD panel. The LCD panels each have hundreds of thousands of tiny pixels, the higher the resolution, the more pixels. Data determines whether light is allowed to pass through each one.

One panel has a red filter, one a green, and one a blue filter. The light is then recombined, using a dichroic prism. The combined, now in full color, passes through the lens and hits your screen.

DLP projectors (except 3 chip). Again, start with a lamp light source. Instead of passing light through an LCD panel, it is reflected off of a DLP chip (which has hundreds of thousands of tiny mirrors), which modulates the light. A color, spinning wheel (referred to as a color wheel), combined with timing, allows the light to come out the correct colors, and pass through the lens on its way to the screen.

DLP projectors - One chip or three?

The vast majority of DLP projectors use a single monochrome DLP chip (officially DMD for "Digital Micro Device), and the aforementioned spinning color filter wheel to generate colors. Unless specifically noted, when this series of articles refers to DLP projectors, they are discussing single chip models.

There is another group of DLP projectors, 3 chip models. These are currently at the top of the food chain, in terms of performance, whether for business or home theater, but as they currently start with selling prices in excess of $10,000, are not widely used, except in high end home theater, screening rooms, and commercial applications demanding the best performance. Three chip DLP projectors function more like LCD projectors. The light source is split into 3 beams. ,Llight is still reflected off of the DLP chips instead of passing though as is done with LCD panels, however, like with LCD projectors the three beams are recombined into a single beam and pass through the lens. It should be noted that 3 chip DLP projectors often use the exact same DLP chips that are used singly in one chip models.

Featherweight Portables, Portables and Fixed Installation Projectors

For purposes of this series of projector advice articles, Portables have been split into two catagories: Under 5 lbs. (featherweights), and 5 - 12 lbs. (portables). There is a definite gray area where portables give way to "fixed/install" projectors, in fact many companies now hang portable projectors weighing less than 5 lbs, in conference rooms. When we refer to fixed/install models, we are primarily referring to heavier units that are more full featured, most typically offering interchangeable lenses, and lens shift, and lots of lumens.

In the portable projector arena, the smallest/lightest projectors around are DLP projectors. This has been true for about 7 years. If you want a 2 or 3 pound projector, today, it is DLP. (Although Panasonic, this month, just announced the first under 3 lb. LCD projector - at 2.9 pounds, with SVGA resolution). The lightest XGA resolution LCD projector is currently 3.7 pounds and there are only a handful under 5 pounds. By comparison, there are probably 3 dozen DLP projectors between 1.98 and 4 pounds. So if you want the lightest and smallest it will be a DLP projector.

The big question is, if you don’t mind a bit more weight - 4 to 7 pound projectors, or you need more features or performance found in the smallest and lightest, what the advantages of each technology, and which is best for you? 

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Advantages of each:

LCD Projectors: Strengths

• Richer color dynamics for better results in rooms with ample ambient light 
• Draw less power
• Throw less heat
• No color filter wheel = No "rainbow effect"
• Slightly quieter Seemingly sharper image on data 

Quicktip: Figure you need about 30% more lumens in a DLP projector to hold its own with an LCD model.

DLP Projectors: Strengths

• Smoother video
• Smaller box
• Pixels far less visible, (although normally not an issue for business use)
• More “filmlike” on DVD and HDTV
• Generate "blacker" blacks
• Higher contrast  

LCD Projectors: Disadvantages

• More visible pixels
• Some screen door effect on certain video images 
• Physically larger - Even for the same number of lumens
• Poorer contrast
• Blacks come out lighter gray than DLP prrojectors

DLP Projectors: Disadvantages

• Rainbow effect bothers some
• More moving parts (color filter wheel)
• Color filter wheel often produces soft but audible whine
• Poorer reds and yellows at full power
• Color saturation
• Need more lumens than LCD, for rich colors, when dealing with ambient light

Overview and Technology
DLP vs LCD Home Theater Projectors
DLP vs LCD Featherweight Projectors (under 5lbs.)
DLP vs LCD Portable Projectors
DLP vs LCD Fixed Installation projectors
A look at other technologies: LCOS, LED, CRT, Laser (coming soon)