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

A design of a large-numerical-aperture aspherical singlet for three-dimensi onal (3-D) sensor applications is presented. This lens can be used to gener ate a homogenous irradiance on the target in a 3-D sensor, which is based o n the principle of time of flight and uses an LED as light source. A numeri cal method was used in the design. The designed planoaspherical singlet has a numerical aperture of 0.67, low refractive index, and moderate surface s hape for easy fabrication. The simulation results revealed that the irradia nce 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 Lambert ian source were compared with those from a point source. (C) 2000 Optical S ociety of America OCIS codes: 150.6910, 220.1250, 230.3670, 150.2950.