HDTV Technology Choices

When it comes to comparing the value of the different HDTV technologies, it’s difficult at times to compare apples to oranges. In preparing this week’s Professor Poor’s Weekly Price Intelligence Report, I found an ad page that provides an interesting comparison. On page 10 of the Best Buy circular, the company offers you three different Samsung HDTVs; take your pick for $1,799.99 (and that’s after their “instant savings”). So what are your choices?

The LNT4066F is a 42″ LCD with 1080p resolution. It has three HDMI connectors.

The HPT5054 is a 50″ plasma with 1356 by 768 pixel resolution, which means that it can produce 720p images without scaling, but not 1080p. It also has three HDMI connectors.

The HLT5676S is a 56″ DLP rear projection model with 1080p resolution. It also has 3 HDMI, and a slim case that is not as deep as most rear projection models.

So, for the same price from the same store from the same manufacturer, you can get a 40″, 50″, or 56″ HDTV. The advantages and the disadvantges of the different technologies can help you choose between these, or maybe you’ll just choose the largest you can get for the money. Which one would you choose?

How do you choose between LCD, plasma, and DLP? The answers are in now available in paperback from Amazon or other fine booksellers.

A New Microdisplay for HDTVs

Plasma, LCD, DLP, LCoS: the current technology landscape is cluttered enough to cause paralyzing confusion for many buyers. The prospect of OLED, SED, and Laser TVs only makes the question of whether to buy now or to wait that much more difficult. But the display industry does not stand still, and the next breakthrough technology may be sitting in some lab somewhere.

For example, consider the “spacial optical modulator” — or SOM — developed by Samsung and described in the current issue of the Journal of the SID. This is an electromechanical device that is able to turn a light beam on and off rapidly, and so can be used to create an image. A DLP chip uses tiny mirrors that rock back and forth to create a pixel. The SOM uses a tiny ribbon that flexes up and down to diffract the light, causing it to either reflect towards the display screen, or be dispersed away from the lenses.

Samsung's SOD is a moving diffraction grating that redirects laser light.

These tiny ribbons move with incredible speed; it takes about seven microseconds to change position. In other words, it can turn off and on about a thousand times in the amount of time that it takes an LCD panel pixel to change once. The ribbons can be built in an array, creating a strip of pixels. Samsung scientists report building a prototype with 1,080 pixels. They then used three of these — illuminated by red, green, and blue lasers — to create an image. A moving mirror was used to scan the columns of pixels across a rear projection screen, creating a 1,920 by 1,080 display for a 1080p resolution. The prototype had 1,000:1 contrast, which is impressive for a new design.

This technology is interesting on a number of counts. It’s small, and is designed to work with lasers from the start. (This also makes it useful for controlling data in fiber optic applications as well.) Lasers should make it possible to make rear-projection displays with much thinner cases, because the laser light is in a coherent beam and thus can be directed more efficiently. The SOD is fast, so it should be able to create an image with great color depth and no motion artifacts. And best of all, it’s a Samsung project, which is a large company that has the resources to sustain this sort of research, and already has demonstrated on-going commitment to rear-projection HDTVs.

Still, the fact is that most novel display technologies never make it to market. Many hurdles remain. Can it be mass produced with acceptable yields? Can it be produced at a competitive cost, which is a fast-moving target as prices keep dropping? Will the image quality be as good or better than the competing designs? And while this eliminates the mechanical color wheel of a typical DLP design, can a scanning mirror be developed that will be rugged, reliable, and affordable? Stay tuned; maybe we’ll be adding SOD to our lexicon of display technologies.

Best Wishes to All!

I’m off enjoying a high-definition holiday today, so I’ll just take this moment to thank all of you for your tremendous support in the past year, to wish you warm greetings of the holiday season, and to hope that you and yours enjoy a happy, healthy, and prosperous new year.


Alfred Poor