An angle is a figure of geometry that is formed by two rays that share the same vertex as the origin. The adjective concave, which comes from the Latin word concăvus , refers for its part to that which exhibits an inward curve.
The idea of a concave angle is usually understood in relation to the notion of a convex angle. For this we must consider that, in the same plane, two rays that are not aligned or coincident and that share an origin, always give rise to two angles: a concave angle and a convex angle. The concave angle is the widest, while the convex angle is the one with the smallest amplitude.
To evaluate the direction of the curve exhibited by these angles, a point of view is necessary: when we say "inward", we refer to a curve that moves away from the observer and "moves into" the imaginary circle that the convex angle completes and the concave. In the same way, the convex angle has its central point more prominent than the rest, that is, it is closer to the observer and protrudes from said circle.
Concave angles, also called entry angles or reflex angles, measure more than 180 ° but less than 360 °. This means that concave angles are never null (0 °), acute (more than 0 ° and less than 90 °), straight (90 °), obtuse (more than 90 ° and less than 180 °), flat (180 °) or complete (360 °). Different is the case of convex angles, which can be acute, right or obtuse, since they measure more than 0 ° and less than 180 °.
For simplicity, to make it easy to distinguish between concave and convex angles, it is often said that concaves are those that measure more than 180 ° and that convex ones are those that measure less than 180 °. In any case, it must be clarified that 360 ° angles are perigonal or complete angles, and not concave, a peculiarity that leaves them out of this simplified classification.
With regard to television screens, in 2013 the Korean companies Samsung and LG presented to the world the first designs based on a concave angle, something that attracted powerfully attention, given that consumers had been happy with their flat monitors for years. But, far from being an arbitrary decision or the intention to establish a passing fad, it is based on an unquestionable feature of our own anatomy: our eyes are curved, and their convexity is perfectly complemented by the concavity of these screens.
The use of a concave angle for the manufacture of screens has already been experimented in several theaters, and experts say it offers a greater degree of immersion in the content. While at first the public feared that the image would be distorted by the curvature, the manufacturers maintain that this happens with flat screens, where all the points of the scene are at the same distance from our eyes, something that is not it can happen in reality.
If we look at a very wide building, the edges of our eyes will capture the image at a slightly different distance than the center, and this generates a certain distortion that is natural to our species. Therefore, the concave angle of modern televisions serves to offer a more realistic and easier to decode experience for the brain than all the previous proposals.