An angle is a figure of geometry that is formed by two rays
that share the same vertex as origin. The concave adjective,
which comes from the Latin word concăvus, refers, for its part, to
what 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 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
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 "enters" the imaginary circle that complete the
convex angle and the concave. Similarly, the convex angle has its center point
more prominent than the rest, that is, it is closer to the observer and
protrudes from said circle.
Concave angles, also called entering angles or reflex
angles, measure more than 180 ° but less than 360 °. This
means that the concave angles are never null (0 °), acute (more
than 0 ° and minus 90 °), straight (90 °), obtuse (more
than 90 ° and less than 180 °), flat (180 °) nor complete (360
°). Different is the case of the convex angles, which can be acute, straight 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 feature 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 television screens. In the
first case, convex mirrors allow the observer's field of vision
to be widened, which is why they are used in parking lots, in cars and at
certain busy crossings to minimize the risk of car accidents.
Regarding television screens, in 2013 the Korean companies Samsung and LG presented
the first designs based on a concave angle to the world, something that caught
the eye powerfully, given that consumers had been happy for years with their
flat monitors. But, far from being an arbitrary decision or the intention of
establishing 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 various cinemas, and experts say that it offers a
greater degree of immersion in 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
that generates 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.