Feb
26
Digital Light Processing (DLP)
Filed Under Front Projection, Terminology
In order to discuss the different display technologies effectively (at a later date) we’ll need to define some of them upfront. I could have started with LCD, plasma, D-ILA, SXRD or any number of others but I wanted to start with DLP (Digital Light Processing) as its one of the most common front projection technologies in use and well, front projection is just plain cool. DLP was developed by Dr. Larry Hornbeck at Texas Instruments in the late eighties but believe it or not front-projection wasn’t one of the first implementations. It (DLP) was actually used to fuse red dyes (text and images) onto airlines tickets.
DLP uses millions of moving micro-mirrors to create the images we see on-screen, the mirrors are fixed to a chip called a Digital Micromirror Device (DMD) which is illuminated by the projectors lamp (gross oversimplification). The technology is known for its accurate colors, sharp images and often better than average contrast ratio.
DLP’s create color by focusing the light path through a color-wheel; multiple “colors” are projected by varying the speed of the color wheel. Early DLP’s were prone to smear colors (known as rainbow effect) due to the slow speed of color-wheel but this was all but eliminated in recent models by higher-speed, multi-segmented color wheels.
3-chip DLP projectors eliminate the color smearing problem altogether with the use of one DMD per primary color, i.e. red, green and blue. 3-chip DLP’s are quite expensive when compared to their single-chip counterparts but are generally perceived as superior in all regards.
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