LED 광원을 이용한 항해등 조명광학계 개발

Abstract

This study is for enhancing the reliability of the navigation light by replacing the halogen lamp, the light source of the existing navigation light, for LED. As the light source was replaced with LED, the light source part and the lens part were required to be designed, and the drawback of the existing navigation light that the stability was vitiated by two-layer lamination was required to be supplemented. A LED illuminating optical system is comprised of a light source part, lens part and shielding part, and should be designed to finally have light intensity distribution conforming to the COLREG (Convention on the International Regulations for Preventing Collision at Sea). The design was carried out using the “LightTools” program, and the light intensity distribution of the final product was obtained by measuring the back light (Goniophotometer NEO LIGHT 9700). Five LEDs arranged at a uniform interval were used in the light source part, and each light source part of the navigation light with the exception of that of the Masthead Light was organized using only 3 LEDs. The light source part was produced in a thickness enough to control the heat of the LEDs, and was made considering the optical characteristics so that it can satisfy the light intensity distribution together with the lens part. Also, the reliability of the LED navigation light was enhanced by arranging 5 LEDs at 50 mm intervals as two systems. The lens part was designed using a spherical lens instead of the existing Fresnel lens, and a lens with two curved surface at an interval of 50 mm was optimized to fit the LED light source organized by two systems. The outer radius of the lens was set to be 91 mm for coupling with the outer box, and the radius of curvature was calculated to be 72 mm. The lens was made of polycarbonate with the reflective index of 1.56. The shielding part which was used to shield the light beyond the range of plain light was designed in two types, the cutoff plate and the back shield plate, and was designed to be suitable for each navigation light in accordance with the light intensity distribution regulation of each navigation light specified in "COLREG". Comparing the light intensity distribution of the final design of navigation light and the actual product with that specified in "COLREG", were found to be conforming.