Design of an aspherical lens to generate a homogenous irradiance for three-dimensional sensors with a light-emitting-diode source

Abstract

A design of a large-numerical-aperture aspherical singlet for three-dimensional (3-D) sensor applications is presented. This lens can be used to generate a homogenous irradiance on the target in a 3-D sensor, which is based on the principle of time of flight and uses an LED as light source. A numerical method was used in the design. The designed planoaspherical singlet has a numerical aperture of 0.67, low refractive index, and moderate surface shape for easy fabrication. The simulation results revealed that the irradiance deviation within 97% of the designed area is less than 5% and that the transmittance of the lens is greater than 90.5%. The results from a Lambertian source were compared with those from a point source.