The washing floodlight is a sort of optoelectronic equipment for the use on vessels which contain helipad, designed as a visual landing aid for the helicopter. Usually the washing floodlight is installed directly on the edge of deck, while the installation site should not be too high, normally lower than 350mm is recommended. In addition, since floodlight generally provides high and relative uniform illumination for a larger deck surface, it is necessary to have a reasonable light intensity distribution, high light intensity and high light energy efficiency. Meanwhile, the floodlight need to provide not only visible light but also infrared illumination to coordinate with night vision goggle. This paper provides a washing floodlight design with high light intensity and high average illumination. The illumination optical system consists of two separate portions, namely refraction and reflective illumination optical system. The refraction illumination optical system is a cylindrical lens with free-form surface, the upper part of lens is responsible for small angle illumination (about 0° to -5 ° in the vertical direction), while the nether part is responsible for large angle illumination (about -5 ° to -30 °in the vertical direction). Besides, the reflection illumination optical system is a cylindrical mirror with scaly conicoid reflection surfaces rather than traditional smooth quadric surface, which can improve the ability to control light, providing a larger angle of uniform illumination. In the later part of this paper, the illumination performance with 8 washing floodlight is simulated, and the illumination performance picture of a real washing floodlight is given.
Fly’s eye uniformizer is the key part of ArF lithography illumination system, whose main function is to illuminate the reticle uniformly. Due to the periodic structure of regular fly’s eye uniformizer and the high coherence of the ArF laser, the output intensity distribution is modulated with equidistant sharp intensity peaks (interference speckle pattern) which disturbed the uniformity on the reticle. In this paper, we design a chirped fly’s eye uniformizer which consists of chirped fly’s eye and a condenser for illumination system in ArF lithography system. The chirped fly’s eye consists of individually shaped micro-lenses defined by a parametric description which can be derived completely from analytical functions. The micro-lenses with different thicknesses in the chirped fly’s eye have a function of delaying the optical path which reducing the laser coherence and speckle pattern on the reticle. Detailed design process of the chirped fly’s eye uniformizer for numerical aperture (NA) 0.75 lithography illumination system is presented. Light intensity distribution on reticle produced by regular and chirped fly’s eye uniformizer are analyzed and compared by the method of wave optics, and the results show that chirped can restrain sharp intensity peaks efficiently. Furthermore, the chirped fly’s eye uniformizer has been traced in LightTools software under conventional and annual illumination modes, and the non-uniformity of the non-scan and scan direction on the reticle reached 0.75% and 1.24% respectively. The simulation results show that the chirped fly’s eye uniformizer can provide high illumination uniformity and reduce the speckle pattern efficiently without additional elements.