How Do 3D TVs Work?

The image displayed on a TV screen is two-dimensional (2D), so, regardless of the technology used to produce the image, three-dimensional (3D) TV screens rely on the way in which human beings perceive depth to create an illusion of three dimensions. Essentially, if the left and right eyes are shown alternating images of the same object from two different perspectives and the images are refreshed quickly enough, the brain combines the images into a single 3D image.

Types of 3D TV

Nowadays, 3D TV may or may not require viewers to wear special 3D goggles, or glasses, but most still do. Those that do can be divided into “active” and “passive”, but it’s worth noting that these terms apply to the nature of the goggles, or glasses, required to achieve the 3D effect, rather than the nature of the TV itself. Those that don’t are known as “autostereoscopic” 3D TVs.

Active 3D TV relies on active, or battery-powered, eyewear. The 3D TV sends a series of wireless signals, via a Bluetooth or radio frequency transmitter, to the eyewear, which causes the shutter on each eye to open and close at the appropriate frequency to fool the brain into seeing a single 3D image.

Passive 3D TV is less sophisticated and simply relies on the filtering effect of the eyewear to create the illusion of a 3D image. Indeed, some passive 3D TV still relies on red/blue glasses, of the type used in movie theatres, but this technology affords only limited colour depth and resolution and is gradually being replaced by later, more sophisticated technologies. So-called Film Patterned Retarder (FPR), a technology developed by LG, relies on polarized filters on both the eyewear and the TV screen to create the 3D effect.

Stereoscopy is the name given to the optical technique by means of which 3D TVs blend together two images of the same object to produce a single, apparently 3D, image. Autostereoscopic 3D TVs rely not on eyewear, but on one of two technologies, known as parallax barrier and lenticular array. Parallax barrier is the more popular of the two for consumer 3D TVs and relies on a fine grating, or parallax barrier, positioned on the front of a liquid crystal display (LCD) panel, which directs alternating images to the left and right eye of the viewer. Lenticular array, on the other hand, relies on an array of tiny, cylindrical lenses, also known as “lenticules”, which magnify and direct the images. In both cases, autostereoscopic 3D TVs have one or more optimal “sweet spots” for optimal viewing. [tp lang=”en” only=”y”]Click here for televisions[/tp][tp not_in=”en”]Click here for televisions[/tp] that allow you to watch 3D TV with or without eyewear.

Considerations

Refresh rate, or the number of times the image on a TV screen is repainted, or refreshed, per second, is one area where, traditionally, plasma held an edge over competing LCD and LED technologies. Refresh rate is important because it affects the ability of a TV screen to display 3D content in “Full HD”, which requires 1,080 lines of effective resolution. Nevertheless, the refresh rates of LCD and LED TVs are increasing all the time and some [tp lang=”en” only=”y”]superb LED TVs[/tp][tp not_in=”en”]superb LED TVs[/tp] are available.