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What Are Passive 3D Glasses?

Passive polarization glasses are used in many movie theaters.
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  • Written By: Suzanne S. Wiley
  • Edited By: Rachel Catherine Allen
  • Last Modified Date: 07 December 2014
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Passive 3D glasses, also known as polarized 3D glasses, are glasses that allow viewers to watch movies or television in 3D without actively changing the picture as viewed through the lenses as the movie progresses. These types of glasses include both the paper frames with red and blue plastic lenses that used to come in children’s magazines and the more high-tech plastic and metal frames that resemble sunglasses. The red and blue-lensed paper glasses are disposable and have remained a niche form of 3D technology. The passive 3D glasses that come with 3D televisions are reusable and have lenses that, to the untrained eye, look exactly the same and do not have different colors.

Active 3D glasses have circuitry that works in concert with the television to actively — hence the name — change how the lenses present the view of the screen to the wearer’s eyes. This process continues throughout the film or program, with instructions from the television to the glasses causing the lenses to change in undetectable increments. Passive glasses have that name because there’s no activity in the lenses or frames. All the activity that enables the wearer to see the 3D effects is in the wearer’s eyes and brain. The glasses do nothing.

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There are a number of benefits to using passive 3D glasses instead of active 3D glasses has a number of benefits, not the least of which are cheaper cost and lighter weight. The glasses don’t require any power or moving parts, so the cost of manufacturing them is substantially less than that of active 3D glasses. Those passive glasses that cost a lot are those that have the fancier bells and whistles, such as clip-on lenses or special styling. The lack of circuitry contributes to the lightweight nature of the glasses, making it easier to wear them for a longer time. Some brands of passive glasses look like plain eyeglasses, too, instead of something out of a science fiction movie.

One of the downsides to these types of glasses is that they can make a video appear slightly fragmented, as if lines were running across the screen. The extent to which this happens varies from brand to brand, so consumers have to test each model when they buy a pair, rather than going solely by price and style. Another disadvantage is that passive 3D glasses can worsen the picture quality because of the optical effects from the lenses.

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Ruggercat68
Post 2

I wish they would show more 3D movies on regular television, but I can understand why they don't. If you don't have the glasses, the movie can be very hard to watch. One of our local stations used to show old 3D movies at night and we'd have to go to certain stores to buy the glasses. I think it would have been a better experience if the reception on our TV had been better. I think people with large digital TVs and cable service would probably enjoy the old time 3D movie experience once in a while.

Cageybird
Post 1

The very first time I remember wearing passive 3D glasses was during a special midnight showing of an old 50s 3D movie called "Cat Women of the Moon". They had the red and blue lenses, and the movie had red and blue ghost images on either side of the actors. I had to cross my eyes a few times to get the full effect, but it really looked like the actors were popping out of the screen. It gave me a headache after twenty minutes or so, though.

I had a chance to watch a modern movie in 3D last year, but the glasses looked different. I believe they were polarized. The 3D effect was different than the 50s version. The actors didn't look like they were popping out of the screen; they looked like they were walking deeper into the scenery. It was a more convincing effect, but I don't think they were trying to dazzle the audience as much as the older movies.

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