Polarized (or Passive) 3D or Active 3D Technology
Passive 3D Technology
In short the passive 3D technology means that two images are projected onto the same screen through different polarizing filters. In order for the 3D effect to become real in your brain, you will need to wears low-cost eyeglasses (usually less than $9) these polarized glasses have the red and blue colors filter lenses.
Through the colored filters, each eye sees a different picture (each filter allows the light which is similarly polarized and blocks the light polarized in the opposite direction). In the Passive 3D technology the TV or projector will be projecting the same scene into both eyes, but depicted from slightly different perspectives.
Active 3D Technology
The Active 3D Technology (which by the way has been adopted by most consumer electronics firms) works a little differently, the “active” means that two different scenes will be displayed one after the other in super fast speed. In active 3D technology a 3D capable HDTV will display one image to your left eye and one image to your right eye.
Since the effective frame rate is halved, these HDTVs need to have double the refresh rate of HDTVs (60 Hz). Before you buy a 3D HDTVs make sure it has a minimum frame rate of 120 Hz (most have a frame rate around 240 Hz or even 480 Hz).
For watching 3D at home must need an extra accessory – An active liquid crystal shutter glasses must be worn by the viewer for him to see the movie in 3D. The 3D shutter glasses quickly block each eye in sequence (around 240 or even 480 time a second) this is needed to ensure that each eye only sees the corresponding image being displayed on the 3D TV set. The active shutter glasses are kept in sync with the HDTV using Bluetooth, infrared, or radio technology. These special glasses usually contain liquid crystals that can be made opaque, thus acting as a shutter. These glasses are battery-operated (battery life estimated at around 80 hours or so).
Which 3D HDTV To Buy? Passive Or Active 3D?
The best thing before you buy a 3D HDTV will be to learn more about the technology it uses. You can even go to an electronic store and try to watch different brands of TV with the active/passive 3D technologies to get the look and feel of the 3D experience. Try to feel which 3D technology is best for you. People enjoy 3D movies in different ways, some say that they can’t enjoy a 3D movie with shutter glasses because “active 3D TVs give them a headache”.. Hi Definition TV people think that “passive 3D TVs don’t have such good resolution” and all the fun is ruined.
Passive technology is more easy to be implemented. Many TV manufactures will boast to launch a 3D compatible TV.. They will show a movie that with the simple polarized glasses will look 3D. But most of them have a lower 3D resolution than most active models when they run in 3D mode.
The most important factor to check in an active 3D technology, is the refresh rate speed – the faster the HDTV can refresh the movie scene the smoother 3D effect will be. If the refreshing will be too slow the viewer eye might detect the shuttering (blinking) and feel that the movie is giving them a nasty headache.
Usually modern TVs are 100 Hz active 3D TVs are similar. If you plan to enjoy 3D movies or 3D games you might wish to invest a little more and get the higher refresh rates like 200 Hz or 400 Hz. When the refresh rate is high as 240 Hz or 400 Hz, the 3D effect will be much better, more vivid and real looking. In those high speed Hz it is less likely it your eye or any human eye will notice the shuttering effect.
Watching 3D With a flat-screen TV?
It is possible to get a passive 3D-capable TV and watch 3D movies, but it is far from optimal. For active technology there are plenty of LCD and plasma 3D-capable TVs with active-shutter technology. As it seems right now (2011) all top TV brands are making the LCD and Plasma the mainstream of 3D television. Your old TV set will not be enough.. for watching 3D you will need a special 3D-capable TV.
Watching 3D With a projector?
In order to see 3D in passive technology, you will need a special 3D-capable polarizing projector. Another important accessory you must have is the special silver screen that reflects the polarized light properly. Without the silver screen the two polarized images will not be sharp and the whole image will be blurry. Take in mind that buying the special silver screen costs much more than a regular white screen. Unlike the 2D screening you can’t just use your wall it is not reflecting the light like the silver screen. If you have a home theater you can invest in an aluminium-coated wall!
3D Active Glasses Vs. Passive 3D Glasses?
The passive 3D glasses are cheap – Just a few bucks for each pair of glasses. When you buy them find out what kind of 3D polarized setup your TV has, there are two kinds of polarisation linearly-polarized setups, and circularly-polarizing setups. Since no head tracking is involved, several people can view the stereoscopic images at the same time. With polarized glasses while watching a 3D movie, tilting of the head can be only to a minimum level, after that the 3D effect is lost.
The shutter glasses are a different story, first they cost about $80-$150 a pair, and second thing is that they are designed to be snchronized only with the 3D HDTV from the same manufacturer. This will change soon, you might find online shutter glasses that are supposedly cross-compatible. If you find such shutter 3D glasses buy the ones that are synchronizedwith the same technologies the TV uses (blue-tooth or radio). Tilting the head with shutter glasses can be done more freely and the 3D effect will be kept, meaning sitting around a TV in wider angles is possible.
Now in case you want the family or all your friends to come over and watch a 3D movie together, you will need several 3D shutter glasses.. and that can be quite expensive.
3D Conclusion which 3D is best?
As you found out it depends on how much you are willing to invest, and how you wish to enjoy the 3D home experience.
The active 3D technologies are better! Serving a superior technology, which will keep getting better, as most of the TV manufactures see them as the next generation.. The passive technologies are a bit left behind as they have no further way to develop, their main advantage as to this point is that they are cheaper, and do not need expensive accessories.
If you have the spare money it is recommended to invest in the active 3D TV sets and accessories, if you wish only to upgrade your movie watching experience at a lower budget, go for the passive 3D compatible HDTVs.
Read More On Active Shutter Glasses