Abstract
In this paper, we propose the optical system design for a medium sized LED marine lanterns which simplifies the multi-layer structure into a single structure. In order to satisfy the target fixed intensity(35,000cd) and vertical divergence($-2.5^{\circ}{\sim}-4.0^{\circ}$, $+2.5^{\circ}{\sim}+4.0^{\circ}$), we use the total internal reflection collimator lens. And a Monte Carlo simulation has been utilized to optimize a condition of a LED package, TIR lens and outside lens. The computer simulation results indicated that this LED marine lanterns can produce of a fixed intensity(35,382cd) and vertical divergence($-3.1^{\circ}{\sim}+2.5^{\circ}$). Using the this optical system, we achieve the target value of LED lanterns.