With three-dimensional (3D) televisions on the market, many consumers are looking for 3D TV glasses that will allow them to view movies and television shows made for this technology. Many people know about the paper glasses with the red and blue lenses, because these are inexpensive and have been around for years. There are, however, new ways to view 3D images, because newer technology has made different types of 3D glasses possible. One example is the polarized type of glasses, which falls in the passive category of glasses as an updated version of the kind with red and blue lenses. Active glasses also are popular, especially among those who crave the ability to see colors accurately when watching 3D television.
The least expensive kind of 3D TV glasses is the passive type. The most common example of this is the flimsy cardboard glasses featuring one red lens and one blue lens, which many people have used during their childhood. This product is referred to as anaglyph glasses and would not work very well with 3D televisions, because the colors would not be accurately portrayed. With this technology, two different projectors are used to put a red image and a blue image on the screen. When viewers use anaglyph glasses, the blue lens can filter the red image, while the red lens filters the blue image, creating an optical effect that makes the images on the screen appear to pop out.
Another example of passive 3D TV glasses is the polarized kind, which has generally replaced the anaglyph type so colors are more accurate, though the idea is the same. As with anaglyph glasses, two projectors, each with a different polarization, place an image on the television screen. Each polarized lens filters an image, enabling each eye to see a different picture, which results in the appearance that the image is 3D. Linear passive glasses require viewers to look straight ahead at the screen to see the 3D images, because moving the head from one side to the other can mess up the optical effect. For this reason, circular passive glasses are more popular, because viewers can still see the 3D image when they angle their head.
Active 3D TV glasses are usually more expensive, but they are often preferred to the passive type because this technology is more compatible with modern 3D televisions. In most cases, liquid crystal display (LCD) lenses alternate between opening and closing at different times so each eye sees a different image on the screen, resulting in the 3D optical effect. These glasses are usually called active shutter 3D TV glasses, and their drawbacks include a higher price than passive glasses, and the need for a power source. In addition, each eye sees the screen at different times, because each lens opens and closes, which means the frame rate is essentially cut in half, slightly reducing image quality. For many people, the ability to view accurate colors on 3D images without much eye strain is worth any drawbacks, which is why these 3D TV glasses are popular.