Optical design of miniature projection lighting system

With the advancement of technology, miniature projector equipment has become the mainstream direction of the projection display industry. Designing an efficient and lightweight LED lighting system is the focus of the lighting part of the mini projection lighting system. This paper designs a miniature projection lighting system, which consists of LEDs, TIR lens, fly’s-eye lens, relay lens and so on. Firstly, based on the theory of non-imaging optics, the mathematical formulas of the collimated small-angle refraction surface and the collimated large-angle reflection surface of the TIR lens are derived, and a program is calculated in the MATLAB to obtain a series of TIR lenses. Discrete points and the discrete points obtained in MATLAB are imported into the 3D modeling software SOLIDWORKS to obtain the 3D model of the TIR lens, and the 3D model is imported into LIGHTTOOLS for modeling and simulation. The simulation results show that the divergence angle of the light of the TIR lens is within 5 degrees, which meets the design requirements. Next, the theory of the fly’s-eye lens is elaborated and the formula of the double-row compound eye lens is deduced in detail. Finally, based on the design of the TIR lens and the fly’s-eye lens, the focal length of the relay lens is calculated. The relay lens is also designed in ZEMAX. In the process of designing the relay lens, the influence of the aberration of the imaging system on the image quality is considered. The spherical aberration, coma aberration, field curvature and other aberrations of the lens are optimized, and finally the relay lens conforming to the design is obtained in ZEMAX. Finally, the TIR lens, compound eye lens, and relay lens are imported into LIGHTTTOOLS for modeling and simulation. A rectangular light spot with a uniformity of more than 90% is obtained, and the lighting system is compact. which meets the design requirements.