All around the SID 2011 exhibit hall, a battle raged. In many booths, you could find proponents of the Shutter Glasses (SG) approach to stereoscopic 3DTV. This presents full screen images for left and right eyes, in rapid succession. The glasses synchronize with the screen so that the image is blocked or transmitted to each eye as needed. And that’s why we call them “active glasses.”
On the other side, you’ll find the approaches that use a Patterned Retarder (PR). This technology uses an extra polarizing layer to change the light in alternating stripes on the screen. You then wear polarized glasses that let light from one set of stripes reach one eye, and light from the other stripes reach the other eye. The glasses are just like the ones you would wear to watch a 3D movie at a local cinema, and are little more complex than a pair of regular sunglasses.
Both approaches have their advantages and disadvantages, but the marketing rhetoric is heating up as each camp tries to paint the other in the worst possible light . As a result, both sides are overstating their claims and will probably succeed in confusing consumers to the point of inaction. (We saw something similar in the Blu-ray versus HD-DVD conflict.)
The interesting change shown at SID 2011 was a third way. Samsung has teamed up with RealD to create a new stereoscopic television technology. Like an AS design, it presents a full screen image for each eye, one after the other in rapid succession. Like a PR design, however, it uses passive polarized glasses like the ones you wear in the movies.
It achieves this magic by adding a second LCD panel over the first. All the second one does is change the polarization of the light, switching rapidly for the left and right eye images. This delivers the full resolution of the image to each eye, but you still enjoy the simplicity and low cost of the passive glasses.
How much more does it cost to add the second LCD panel? We don’t know because this new approach isn’t on the market yet. At first glance, it may seem that it would add a lot to the price of a 3DTV set. The panel would be very simple, however, with no color filter required. According to DisplaySearch, a color 42″ LCD TV panel costs $235, so the extra panel would presumably cost less than that. This could well be competitive with the costs of the patterned retarder, or the extra cost of active glasses when buying for a whole family.
We’ll see if this new approach gains any traction in the marketplace, but for now, just remember to take comparitive claims from the competing camps with a large grain of salt.
Posted by Alfred Poor, May 20, 2011 6:00 AM
About Alfred PoorAlfred Poor is a well-known display industry expert, who writes the daily HDTV Almanac. He wrote for PC Magazine for more than 20 years, and now is focusing on the home entertainment and home networking markets.