Parallax barrier
A parallax barrier is a device placed in front of an image source, such as a liquid crystal display, to allow it to show a stereoscopic image or multiscopic image without the need for the viewer to wear 3D glasses. Placed in front of the normal LCD, it consists of a layer of material with a series of precision slits, allowing each eye to see a different set of pixels, so creating a sense of depth through parallax in an effect similar to what lenticular printing produces for printed products.[1][2] A disadvantage of the technology is that the viewer must be positioned in a well-defined spot to experience the 3D effect.[3] Another disadvantage is that the effective horizontal pixel count viewable for each eye is reduced by one half; however, there is research attempting to improve these limitations.[4]
Applications
In addition to films and computer games, the technique has found uses in areas such as molecular modelling and airport security.[5] It is also being used for the navigation system in the 2010-model Range Rover,[6] allowing the driver to view (for example) GPS directions, while a passenger watches a movie. It is also used in the Nintendo 3DS hand-held game console[7] and LG's Optimus 3D and Thrill smartphones,[8] HTC's EVO 3D[9] as well as Sharp's Galapagos Android SmartPhone series.
The technology is harder to apply for 3D television sets, because of the requirement for a wide range of possible viewing angles. A Toshiba 21-inch 3D display uses parallax barrier technology with 9 pairs of images, to cover a viewing angle of 30 degrees.[10]
Overview
There are 3 main types of Autostereoscopy displays with parallax barrier
- Early experimental prototypes would just put a series of precision slits on regular LCD screen to see if it had any potential.
- First fully developed "Parallax barrier displays" would have have precision slits as one of its optical components over the pixels. This blocks the image from one eye and shows it to another.
- Pros
- Cons
- Least efficient with backlight,
- Needs twice as much backlight as normal displays
- Small viewing angles
- The newest and most convenient design, commercial products like the Nintendo 3DS, HTC Evo 3D, and LG Optimus 3D do not have the physical parallax barrier in front of the pixels, but behind the pixels and in front of the backlight. They thus send not different images to the two eyes but different light to each. This allows the two channels of light to pass through the pixels, allowing glare over the opposite pixels giving the best image quality.
- Pros
- Clearest image
- Only uses 20-25% more backlight than normal displays
- Largest viewing angle
- Cons
See also
References
- ^ "Reviews by PC Magazine - Sharp Actius RD3D". www.pcmag.com. 2003. http://www.pcmag.com/article2/0,1759,1386949,00.asp. Retrieved 2008-01-25.
- ^ "The Register - Sharp's 3D LCD: how's that work, then?". www.theregister.co.uk. 2004. http://www.theregister.co.uk/2004/08/12/3d_illusion/. Retrieved 2008-01-25.
- ^ Norris, Ashley (2002). "Guardian Unlimited - Special reports - The return of 3D". London: www.guardian.co.uk. http://www.guardian.co.uk/mobile/article/0,2763,855027,00.html. Retrieved 2008-01-25.
- ^ "Better glasses-free 3-D". http://web.mit.edu/newsoffice/2011/glasses-free-3d-0504.html. Retrieved 1 July, 2011. "A fundamentally new approach to glasses-free 3-D displays could save power, widen the viewing angle and make 3-D illusions more realistic."
- ^ "BBC NEWS - Technology - Easy 3D X-rays for air security". news.bbc.co.uk. 2004. http://news.bbc.co.uk/1/hi/technology/3772563.stm. Retrieved 2008-01-25.
- ^ "Land Rover e-brochure PDF (page 19)". www.landrover.com. 2011. http://www.landrover.com/content/me/english/pdf/me-en/rr-ebrochure.pdf. Retrieved 2011-12-29.
- ^ "Nintendo unveils 3DS handheld games console". www.bbc.co.uk. 2010. http://news.bbc.co.uk/1/hi/technology/10323971.stm. Retrieved 2010-06-17.
- ^ "LG unveils world's first 3-D smartphone". www.cnn.com. 2011. http://www.cnn.com/2011/TECH/mobile/02/15/lg.optimus.3d/index.html?hpt=C2. Retrieved 2011-02-15.
- ^ HTC EVO 3D, from GSMArena
- ^ "Toshiba Mobile Display touts 21-inch glasses-free 3D HDTV, raises a few eyebrows". Engadget. April 27th, 2010. http://www.engadget.com/2010/04/27/toshiba-mobile-display-touts-21-inch-glasses-free-3d-hdtv-raise/.
External links