Theoretical analysis and design for highly collimated planar light source based on organic light-emitting diodes using Fresnel lens

We theoretically design a versatile compact optical system comprising large-scale organic light-emitting diode (OLED) light sources and a freeform Fresnel lens to generate a highly collimated incoherent planar light source (HCIPLS) with uniform irradiance distribution. The structural parameters related to the output collimated light beam are discussed in detail. The simulated optimal full width at half maximum (FWHM) of the angular intensity distribution of the proposed structure is as high as 6.9° at both vertical and horizontal viewing angles. Moreover, the calculated normalized luminance enhancement factor reaches 25.4 in the range of normal viewing angles.