UNDERSTANDING TV AND PROJECTOR VIEWING ANGLES
When shopping for a new display device, whether it is an LCD, Plasma television, LED or a DLP or LCD projector, one specification that it is very important to take note of is the specified maximum viewing angle of the device.
Flat panel displays and projection devices used to have very limited viewing angles. These display devices were designed for "straight on" viewing, meaning that if the device - be it the TV or the projection screen - was viewed from an angle varying substantially from perpendicular, the viewer generally experienced a large amount of image quality loss.
With the advent of home theatre projector systems and the influx of flat screen LCD and Plasma displays, the viewing angle of televisions and projectors is becoming more important and the viewing angle is increasing on most devices. This is mainly due to the way furniture in living rooms or home theatres is often spread out across the room and not positioned directly in front of the television or projector screen.
A device with a large maximum viewing angle will allow for everyone in the room to enjoy the same high quality image. This Projector Source Canada article will explain what a maximum viewing angle is, and what the consequences are if an audience member is situated at an angle beyond it. Viewing angles and how they are measured on varying types of display devices will also be explained.
What is a display device''s viewing angle?
When a TV or projector manufacturer references viewing angle, they are referring to the maximum angle at which an image on their device - be it the television or the projection screen - can be viewed without suffering from any perceived drop in the quality of the displayed image.
The maximum possible viewing angle for any one sided display device is by default 180 degrees, which would mean that the TV or projection screen is being viewed exactly from the side. Obviously, a display device will never have a 180 degree viewing angle, although some devices can get close to this number.
Sometimes, if the quality of the image on a display device is affected when viewing on the vertical plane, manufacturers may specify both horizontal and vertical viewing angles for their devices, although the horizontal viewing angle is by far the more common specification.
It is easiest to imagine the area you can watch the screen from without suffering from image degradation as a viewing cone which spreads outwards from the television or projection screen. Typically, you should only consider devices with a viewing angle of at least 120 degrees.
What are the consequences of a low or poor viewing angle?
If an audience member views a flat screen television or a projection screen from an angle greater than the maximum viewing angle specified for the display device, then the viewer may experience a varying amount of image degradation, which can be annoying and distracting.
For example, the picture may appear blurry, not bright enough, distorted, having poor contrast or lacking saturation. The extent at which these issues occur is entirely dependant on the degree to which the maximum viewing angle is exceeded and the type of display device used. Projector screens, LCD televisions and Plasma televisions are all affected differently and each have varying maximum viewing angle capabilities as well as having differing ways to determine this angle.
LCD and DLP multimedia Projectors
The viewing angle of an LCD or DLP projector is very dependent on the type of projection screen used to display the image. While the image degradation at high viewing angles depends entirely on the material used to make the screen, most materials reflect a greater amount of light perpendicular to the screen and a lesser amount to the side.
If the audience is not seated directly in front of the screen then the image can appear much darker and unclear. As a result, the majority of projector manufacturers define their viewing angle as the angle when the brightness of the image is half of its maximum potential.
Flat panel LCD TVs
When LCD technology was first used in display devices, it was originally implemented for use in computer monitors - i.e. situations where the viewer is directly in front of the screen. For this reason, the maximum viewing angle for an LCD screen was initially very low, as a wide viewing angle was not a necessary feature. While both Sharp and Sony have recently been using new substrate materials on their latest LCD TVs to achieve viewing angles of up to 160 degrees, the fact remains that viewing angles of 120 or 130 degrees are typical for the majority LCD HD televisions and LCD monitors.
The standard for actually measuring the maximum viewing angle on and LCD TV is somewhat variable. Some manufacturers opt to define the maximum viewing angle at the point where the contrast ratio is at 5:1 where as others measure it at 10:1.
Flat panel Plasma TVs
Since the individual pixels in Plasma televisions each produce their own light source, the screen is more visible since every pixel has the same amount of brightness, which is not the case in LCD TV screens. Consequently the viewing angles that Plasma TVs offer is often slightly better than the LCD equivalent. A typical maximum viewing angle for a Plasma screen is 180 degrees.
We hope you enjoyed this article by Projector Source Canada. For more information, or to purchase a display and projector for your business or home, visit us online at http://www.projectorsourcecanada.ca
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