Analytical treatment of light extraction from textured surfaces using classical ray optics

Effect of inverted-pyramid shape on light extraction of organic light-emitting diodes

“…We have discussed in Fig. b that rays can be divided into several regions, and actually the regions may overlap or become unrealistic depending on α and θ C . Here in our experiment, the inclination angle of inverted‐pyramid is between 46° and 54° (i.e., α is between 36° and 44°), and the critical angle of PVA material is about 42°, so the angle θ C + 2 α has become larger than π /2.…”

Invention, development, and status of the blue light-emitting diode, the enabler of solid-state lighting

“…OSRAM Opto Semiconductors soon developed a product line based on the VTF LED [53]. The addition of surface roughening breaks up guided modes in the thin n-GaN and creates an ergodic surface that randomizes the incident angle of incoming photons and increases the single-pass escape probability [42,54]. The surface-roughened VTF LED exhibited a higher LEE from the top surface by a factor of 2-3× compared to an LED with a flat top surface and showed a Lambertian emission pattern.…”

Nanostructuration of YAG:Ce Coatings by ZnO Nanowires: A Smart Way to Enhance Light Extraction Efficiency

“…To reach this objective, several strategies have been developed and reported in the literature. They are based either on the angular randomization of photons by scattering them from a structured surface [ 12 , 13 , 14 , 15 ] or on using an intermediate layer with an appropriate refractive index between the AL and the air [ 4 , 16 ]. In both cases, the TIR will be attenuated and the LEE value will increase, which has been demonstrated on LED chips [ 5 ].…”