Design of a high-power collimating optical system based on Fresnel lenses.

In light-emitting diode (LED) illumination (e.g., LED maritime lighting for ships), creating a uniform light environment for optical systems is an important challenge. In this study, we present a high-power collimating system based on Fresnel lenses, which allows high-brightness LED illumination in the earlier-mentioned remote distance. The work presented in this article focuses on improving the power, compacting the optical structure, and promoting the brightness of the spot. To prove the claims, the system with a total power of 1 kW is designed. The system consists of a 27 W LED array, a freeform surface lens array, and a confocal Fresnel lens array. In comparison with the traditional optical system, the optical structure shortens from 390 to 120 mm, and the divergent angle decreases from 3° to 2 ° $$ {}^{{}^{\circ}} $$ . Meanwhile, the illuminance of the system is obtained as high as 230 lx at the near field of 200 m and 3.0 lx at the far field of 1.5 nautical miles. This new method provides a practical and effective way to solve the problem of low power, insufficient illuminance, and long optical structure for LED array illumination, which is suitable for remote illumination and guidance of ships.
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