With LCD screens, some manufacturers have opted to measure the contrast ratio and report the viewing angle as the angle where the contrast ratio exceeds 5:1 or 10:1, giving minimally acceptable viewing conditions.
The viewing angle is measured from one direction to the opposite, giving a maximum of 180° for a flat, one-sided screen.
A display may exhibit different behavior in horizontal and vertical axes, requiring users and manufacturers to specify maximum usable viewing angles in both directions.
Early LCDs had strikingly narrow viewing cones, a situation that has been improved with current technology.
Narrow viewing cones of some types of displays have also been used to bring a measure of security in businesses, where employees handle private information in the presence of customers, banks being one example.