Construction Method of Tailored Facets for Use in Freeform Reflectors Design

Abstract

A construction method to obtain sets of tailored facets to be used as the initial configuration in the design of freeform reflector surfaces is presented. The construction strategy starts from a collection of flat elementary facets and achieves the initial configuration of the reflector surface by tailoring the facets according to their Bézier surfaces description. The aim of this research is to describe a procedure capable of generating the Bézier surfaces that define elementary tailored facets; these facets could then be used as initial configurations in the design of freeform reflectors. Though beyond the scope of this article, the facets could be used on a subsequent optimization process, i.e., the geometry of the elementary facets could be modified through a global optimization process taking into account all facets, in order to further improve the entire illumination system. Ray tracing is used to calculate the facet's geometry; it applies elementary merit functions to find the parameters defining the Bézier curve that best meets specifications in each elementary facet. This method is based on a sequential 2D projection strategy that employs different strategic planes for calculations. A method to build up the facet's geometry using a Bézier surface from 2D curves is provided. This approach will successfully generate a net of control points to describe a Bézier surface compatible with any standard optical optimization tool and suitable for use with CAD and other tools that represent solids.

Bulletin of the Polish Academy of Sciences: Technical Sciences

“…These are the methods that use surfaces based on mathematical curves [3], mainly the so-called conic curves (circle, ellipse, parabola, hyperbola) and named freeforming (known in the automotive technology as FF) or tailoring, which has been developing intensively in recent years. Tailoring reflectors and lenses can be based on algebraic [4,5], graphic [6,7] or optimization [8] methods. Regardless of their theoretical background, all these methods are based on a homogeneous luminance distribution and overall dimensions of light sources.…”

“…Individual methods differ in the way they describe rays and how they solve the system of equations. In the literature, you can find some descriptions of algebraic methods [4,5] for solving the above system of equations and graphic methods [6,7].…”

Design of freeform lens for WLEDs on the fishing boat

“…Nevertheless, it is hard to get all the abilities of conventional radiation pattern of LEDs fully employed, so the LEDs packages needs support from additional optical devices [9][10][11][12].Therefore, using a secondary freeform lens, which is introduced to convert the raw radiation pattern into a more suitable one, as an additional optical device seems to be the best solution [13][14][15][16][17]. Besides, owing to their freeform surfaces, this kind of lenses can help to generate more uniformity lights and a proper light intensity distribution curve (LIDC) [18][19][20][21]. To the best of our knowledge, there has been no function proposed to achieve an ideal LIDC through the use of secondary lenses.…”

Estratègia 2D per al disseny de reflectors amb facetes de forma lliure

“…2014 • Dissenys de forma lliure utilitzant fonts extenses (Wester et al 2014). 2015 • Mètode constructiu de facetes de forma lliure amb estratègia 2D (Tomás and Arasa 2015).…”