Have you already bought a 3D TV since everyone is crazy about it? Are you searching for good 3D glasses and wondering which ones to buy? Do you know why we need to wear 3D glasses to watch a 3D TV or movie?
Let’s give you a simple concept about 3D technique first. Actually when we view the world, we see the same picture from slightly different angles because our two eyes are spaced about 2 inches. This creates a parallax difference. But our brain can correlate these two images in order to gauge distance and then interpret it as depth.
When people are making 3D movies, they do the same thing by using two cameras separated by a horizontal distance. But when you watch the movies, your brain system need to recreat the depth effect, say, the left eye only see the left camera view and the right eye only see the right camera view. That’s why we need to wear 3D glasses.
As for 3D glasses, the major manufacturers invest in different types. Samsung, Sony, Panasonic, and Sharp are focusing with their 3D developments with shutter Active 3D glasses while LG, Philips, and Vizio are going with passive 3D glasses.
Since there are different types of 3D glasses, what’s the key difference between two types of glasses? Time is the key. Active glasses create 3D imaging sending information to both eyes simultaneously but Passive glasses creat 3D images by sending information to each eye of our eyes in sequence.
Active-shutter glasses use small LCD screens that are commanded to alternately open and shut the left and right lenses in succession and show each eye a different image. All this happens at a very fast speed, which is controlled by the special emitter of the 3D TV, so that you won’t notice the darkening but do see three dimensions. Now most shutter glasses are powered by small batteries and receive sync signals through an infrared beam as a TV remote. Since the Active Glasses are complicated electronics, they are considerably pricey and only can work on 3D TVs made by same manufacturer.
Besides the price, the major disadvantage of Active 3D glasses is that it doesn’t deliver separate images
at the same time. So the images shown to each of our eye will be alternated at whatever the frame rate of the content and refresh rate of the display offers. Plus, active 3D viewing can give our eyes fatigue, or a headache. But since both images are not being overlaid on one another when you’re wearing Active 3D glasses, you can see full color and picture information. And this will provide you almost the best home 3D experience before the 3D without glasses.
On the other hand, Passive 3D glasses function by blocking different kinds of light from each eye, which creates the illusion of depth. This principle of work makes it easy to enjoy the 3D experiences. First of all, you don’t need to buy any kind of expensive electronic glasses which need a power source and you also don’t need a proprietary infrared emitter which syncs with the glasses. Secondly, with the passive 3D glasses, since the viewer is being shown both images at once so it won’t cut the frame rate of the content in a half like active glasses will do. Most importantly, Passive 3D glasses are not expensive.
Basically, there are two major kinds of passive glasses: anaglyph and polarized. Anaglyph glasses are those commonly seen with one red and one cyan lens, which is the least advanced of all glasses. It delivers 3D images by using color to separate the images which will lead to the some or all lose of color information. Polarized 3D glasses come has two forms, linear polarized and circular polarized. Using Linear polarized glasses, you need to keep your head at a vertical position, because tilt your head left or right may break the 3D effects. Well the Circular polarization has no this kind of problem but it requires a special projector and filter(not used on 3D televisions).
Since each lens is blocking out light,wearing Passive 3D glasses, you’re technically not getting a full 1080p image for each eye even the source provided is 1080p. So you’ll get pictures with less depth and quality. But viewing 3D by Passive 3D Glasses won’t cause eye fatigue since the glasses are not frequently opening and closing.
The debate between active and passive 3D will go on because we have so many different options as for 3D TV and 3D Glasses. Besides the manufacturers who produce Passive 3D Glasses or Active 3D Glasses, Toshiba is producing both and also trying to make the first 3D TV without glasses. If this could be done, the other 3D TVs and glasses will never catch up with its step. But as a customer, it will be interesting to see if the competition will lower the price of both 3D glasses or lower the price of Active 3D Glasses due to the overall low price of Passive 3D Glasses.