By Patrick Miller, PCWorld Sep 7, 2011 9:00 AM

Polarized "passive" 3D TVs hit the market in the beginning of the year as a response to the bulky, expensive, complicated active-shutter 3D TVs that turned off many would-be buyers. But many home theater enthusiasts (and TV manufacturers) claimed that they sacrificed image quality in the process. DisplayMate Technologies, a display calibration software developer, pit active and passive 3D TVs against each other to get to the bottom of this and published the results in a freely-available report (3D TV Display Technology Shoot-Out). As it turns out, passive TVs have a more restricted viewable range than active-shutter sets, but they don't lose detail. Read on for more on their testing procedures, as well as our own in-house testing results.

How 3D TV works
When you're watching TV, you're looking at a flat 2D panel. In order to trick your brain into seeing a 3D image in a flat panel, you have to show each eye a slightly different image, which your brain puts together into one image with the illusion of depth.

Active-shutter glasses are actually a pair of small LCD screens alternately block out the image in the left and right lens in sync with the TV, which shows your eyes slightly different images that your brain puts together to create the illusion of depth. Naturally, this gear doesn't come cheap. At first, active-shutter glasses cost around $150 per pair, though recently they've been coming down in price to as low as $50.

Passive 3D TVs use the same glasses you find in 3D movie theaters, which are similar to sunglasses. The passive 3D TV starts by displaying two different images superimposed on each other through a polarized light filter. Each lens in the passive 3D glasses has a filter that allows a different image in, so each eye can receive a different half of the image and produce the 3D illusion without depending on any electronics in the glasses.

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