Digital Trends

Samsung HLN617W March 25th, 2004 | by Brandon King

Introduction

Making a decision on what HDTV set to purchase involves not only evaluating different brands, but also comparing different competing technologies. The Samsung HLN617W rear projection TV featured in this review is based on DLP, a relatively new technology in the HDTV arena. Before we discuss this particular unit, we thought it best to explain the basics of DLP.

DLP stands for Digital Light Processing, a technology created and patented by Texas Instruments. The general idea is not simple, and not intuitive. The core of DLP is a chip with over a million tiny mirrors that can be tilted to reflect a light source. If tilted to the “on” position, the light reflects through a lens and onto the screen, creating white. When in the “off” position, the mirror is tilted so that no light passes through the lens. Gray is created by switching between “on” and “off” faster than the eye can perceive, with lighter gray consisting of more “on” states, and darker with less. Color is added by the addition of a color wheel that spins in front of the reflected light. The color wheel is 1/3 red, 1/3 green, and 1/3 blue. The shifting of the mirrors is coordinated with the fixed speed of the color wheel, and it is this combination that allows for the correct color to be displayed on the screen. The Website DLP.com features a great demonstration of DLP technology if you'd like to get more in depth.

DLP inherently does not suffer from burn in, like plasmas and CRT displays, or ghosting, like LCD rear projection and front view units often do. Most DLP sets are on par with LCD rear projection units as far as depth, but are not in the same league as front view LCDs and plasmas.

Few people report to experience what is called the “rainbow effect” when viewing DLP displays. While we have yet to meet one, and over 40 people have viewed our Samsung review unit, it is described as a rainbow of color at the borders of white and colored areas. This is due to the perception of the color transitions as the color wheel moves from one colored third to the next. The next generation of DLP sets will use the new HD2+ chips which uses enhanced technology to help eliminate the rainbow effect, in addition to the 7 segment color wheel (instead of the current 6 segment one).

So which type of HDTV display is right for you?  Each technology has their pros and cons. Gamers may want to look at something other than LCDs because of a possibility of the ghosting we mentioned before. CRTs are big and heavy, and people who don't have a lot of room or want the television to be upstairs, may want to choose something else. Plasma displays are thin and light and look great as the centerpiece in a room, but the price of the larger plasma screens can be quite prohibiting.