A angle is a figure of geometry that is formed by two rays that share the same vertex as the origin. Adjective concave, which comes from the Latin word concăvus, refers for its part to that which exhibits an inward curve.

The idea of ​​concave angle is usually understood in relation to the notion of 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 wider, 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: when we say “inward”, we refer to a curve that moves away from the observer and “enters” the imaginary circle that is completed by the convex and concave angles. 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 incoming angles or reflex angles, they measure more than 180 ° but less than 360 °. This means that concave angles are never null (0 °), treble (more than 0 ° and less than 90 °), straight (90 °), obtuse (more than 90 ° and less than 180 °), plains (180 °) nor complete (360 °). Different is the case of convex angles, which can be acute, straight or obtuse, since they measure more than 0 ° and less than 180 °.

For the sake of simplicity, to make it easy to distinguish between concave and convex angles, it is often said that concave are those that measure more than 180 ° and that the convex ones, those that measure less than 180 °. Anyway, it should be clarified that 360 ° angles are perigonal or full angles, and not concave, a peculiarity that leaves them out of this simplified classification.

These concepts have many applications that exceed the limits of mathematics and physics, since they are used in the manufacture of various products, among which we can highlight mirrors and tv screens. In the first case, Mirrors Convex allows to extend the field of vision of the observer, and for this reason they are used in parking lots, in cars and at certain busy intersections, to minimize the risk of motor vehicle accidents.

Regarding the screens television, in 2013 Korean companies Samsung and LG They introduced the world to the first designs based on a concave angle, something that attracted powerfully attention, given that consumers had been happy with their flat panel monitors for years. But, far from being an arbitrary decision or the intention to establish a passing fad, it is based on an unquestionable characteristic 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 cinemas, and experts say that offers a greater degree of immersion in content. While at first the public feared that the image would be distorted by the curvature, manufacturers maintain that this happens with flat screens, where all points in the scene are at the same distance from our eyes, something that cannot happen in reality.

If we look at a very wide building, the edges of our eyes will capture the image at a distance slightly different than the center, and that creates a certain distortion that is natural to our species. Therefore, the concave angle of modern televisions serves to offer a more realistic and easy-to-decode experience for the brain than all the previous proposals.