Advances in 3D TV: The latest addition to the home media room

The theatre rooms that have become so popular in home design and are dedicated to viewing movies, with associated theatre style seating and dark walls and floors, are morphing into media rooms. Unlike the theatre room, which has a fairly limited function, media rooms have multiple functionality for family entertainment, including movie viewing, gaming, internet surfing and other forms of family entertainment. With new home sizes getting smaller as a result of tighter economic times, rooms with multipurpose functionality are becoming more important, as is designing this functionality around future technologies. As technology advances in the home entertainment arena, realistic surround sound and vibrating seats are no longer stimulating enough – now, exciting battle scenes must literally jump out and surround the viewer with visual images as well as realistic sound. The new digital 3DTV can be thought of as a 21st-century version of the red-and-green filtered films and paper 3D glasses used in the 1930’s . This article discusses the technology behind 3D and the anticipated future directions for this technology, particularly in the home as it relates to television.

The use of 3D to enhance the viewer’s experience when watching films is nothing new: early 3D films were shown as early as the late 1920’s and early 1930’s. The technology to produce and screen 3D movies has always been difficult compared to flat-screen projection. Each time a technological advance has been made in projection, there has been a delay in the time it took for 3D technology to catch up. This has resulted in “gaps” in popularity and availability of 3D films – a handful of films would be produced, followed by a delay as new technology was introduced, then another handful of films would be produced, and so on. Recently, 3D movies have made another resurgence, as popular producers and large film companies introduce new 3D movies like Avatar which have been very popular and profitable.

Today’s consumers expect quality in their home entertainment systems that is comparable to that found in theatres. As popular movies shown in 3D in theatres arrive in Blueray and DVD formats, home owners want the ability to watch high quality 3D movies at home. Thus, the current push by electronics companies to develop technologies to provide home-based 3DTV.

There are three fundamental technologies behind 3D projection. The first of these is the anaglyph method. The anaglyph method uses 2 different images, slightly offset from each other, each filtered with a different tint, usually red and cyan. The viewer wears the classic 3D glasses, one red lens and one cyan lens. This results in each eye only viewing the image that has the matching tint, creating the stereoscopic image that provides 3D. Typically, the viewer uses an inexpensive pair of disposable glasses to view the movies – most modern 3D blueray movies and broadcasts use this technology. The second technology uses polarized light. Polarized light can be filtered through polarized lenses. Much in the same way the anaglyph method uses two different colors, the polarization method uses crossed-polarized light to create two offset images. The glasses consist of two lenses, each of which passes only one polarization. Thus, each eye views only one polarization and one of the two offset images. The third method of 3D uses shutter glasses. In this technology, each lens of the glasses is synchronized with a corresponding frame of the movie. Rather than simultaneously showing two offset pictures, the shutter technology intersperses offset pictures every other frame, using a temporal effect rather than a spatial one. The shutter glasses are synchronized with the picture through wireless technology, making them somewhat bulkier than polarized or red-cyan glasses.

Televisions with 3D capability have recently begun to hit the consumer market, with a number of electronics companies introducing 3DTV systems based on DLP (digital light processor) technology. These systems began shipping with glasses in 2010. Systems based on both polarized and shutter glasses technologies are now available to consumers. The glasses, however, remain a cumbersome part of the system, and are easy to lose and vulnerable to being broken. There has been considerable research into systems that enable 3D viewing without the use of glasses. Autostereoscopy is the phrase used to describe 3D displays that operate without glasses. The most advanced technologies are the parallax barrier method and the lenticular lens method.

The parallax barrier method uses a screen layer placed in front of the image to effectively create the effect of 3D glasses in the screen itself. This is done by using the geometry associated with the separation of two human eyes and the typical viewing distance between the eyes and the screen. Optical materials match the index of refraction of the screen layer with an optimal separation of “red” and “green” pixels in the image, hence creating a different image seen by each eye. The design of the media room to view such images is crucial – the viewing angle must be near horizontal, and the distance between the viewers and the screen must be roughly the same for all viewers. While this is a big improvement over the previous generation of parallax screens, which accommodated only a single viewer at a fixed viewing angle, it is not compatible with the “theatre” style seating arrangement in some theatre rooms. This technology is currently much better suited to gaming, particularly hand-held gaming, than to family TV viewing.

Lentincular lenses are another technology being investigated for glasses-free 3DTV and consist of lenses that magnify the image differently based on the angle of view. Screens can be constructed using lenticular lens technology to give a 3D effect to the viewer. At this time, the lenticular lens technology as applied to large screens is primarily being used for novelty displays for commercial applications, but companies anticipate that the technology will ultimately become available in the home entertainment market.

Both the parallax barrier and lenticular lens screen technologies can be switched from 3D mode to 2D mode; however, unlike the systems that utilize glasses to view 3D, the glasses-free systems require image processing algorithms to do image correction when switching between the two modes. In the long term, designing media rooms around 3DTV will require unique design considerations – spacing and distance of view, screen placement, and allowing room to fight all of those virtual battles!

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