Fabrication of a Beam Shaping Lens for Chip Scale Packaged LEDs

Abstract

In this paper, we demonstrated the machining process of a novel Light Emitting Diodes (LED) beam shaping lens, called TIR Fresnel lens, for GaN-based blue Chip Scale Packaged (CSP) LEDs. Upon achieving a precise alignment of the tool and identifying the best manufacturing condition, we have successfully fabricated a prototype of this lens on poly methyl methacrylate (PMMA) plate. The form error of the central aspheric lens was less than 1 μm deviation, and surface quality of the Fresnel facets were sufficient for Total Internal refraction without any burr or adhesion of the machined chip. Fabricated TIR Fresnel lens reduced the viewing angle of the testing CSP LED from 140° to 17.4° in FWHM. The proposed lens produced extreme compactness as well as high collimation efficiency, thereby applicable to an ultra-thin optical system.

Design and Manufacture of Light Collimator with Narrow View Angle

“…However, achieving such a high performance with a miniaturized collimator is an improtant technical issue because of its sensitivity to machining. Roughness of the machined optical surfaces of the lens has to be lower than 5 nm; otherwise light scatters and gets lost in the Proceedings of Precision Engineering and Nanotechnology illumination zone [10]. The profile accuracy of optical surfaces is even more important and has to be maintained at less than 10 µm; otherwise sharp gradients in luminous intensity distribution spread out, increasing view angle.…”