As far as total light propagation in optical fibers is concerned, this occurs when the refractive index of the core glass is greater than that of the cladding glass. The beam is then reflected at the transition between the core glass and the cladding glass and remains within the optical waveguide. Thus, the condition of Total Internal Reflection (TIR) is fulfilled.
Light distribution plays the decisive role in the illumination of living spaces and offices, buildings and streets. Since the light emission of light emitting diodes is point-like, diffusion lenses, reflectors and collimators are used for point and diffuse emission of objects with which the light beam can be changed in its beam angle.
TIR (Total Internal Reflection) optics is such a collimator used with power LEDs to collimate the emitted point light, that is: to make the light beam emerge in parallel. It is a combination of reflector and lens that works with refraction and reflection, producing a parallel beam of light like a parabolic mirror. The TIR process is extremely efficient and can focus light energy from different directions. This makes it possible to generate point light.