What is TV Viewing Angle, Side Angle Viewing, Off Axis Viewing?
By Phil Conner
Viewing angle refers to the off angle axis when moving away from 0 degrees on axis in front of a TV. The terms referring to viewing angle are important to understand because there is a frequent problem with many TVs picture quality decreasing due to a hazy effect caused by the screen of the TV itself. Practically speaking as one moves from center couch to side chair, the contrast can appear to degrade with black levels becoming more "washed out" or gray. This is a serious issue with TV viewing as black levels and contrast are key to displaying a good picture quality.
We use the term side angle viewing or off axis viewing to describe the fact that we are not on center and to further elaborate that the angle might be 30 degrees off axis or 45 degrees side angle before contrast starts to degrade. We measure always measure the off axis angle at which contrast starts to degrade or black levels do not maintain their depth because it relates to the quality of the picture and of the manufacture quality of the screen. Plasma TV technology generally does not have a problem with off axis or side angle viewing due to the fact that each pixel is lit separately. LCD TV technology has had issues with side angle viewing due to the nature of the back lighting showing through the panels "twisting crystals".
A good example of the differing levels of contrast degradation between two LCD televisions.