Double-Sided Freeform Lens for Light Collimation of Light Emitting Diodes

Yong-Sin Syu,Chun-Ying Wu,Yung-Chun Lee

doi:10.3390/app9245452

Yong-Sin Syu, Chun-Ying Wu + Show 1 more

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https://doi.org/10.3390/app9245452

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Abstract

A double-sided freeform lens is proposed for collimating light emitted from light emitting diodes (LEDs). The surface profiles of the lens are mathematically characterized and precisely determined based on a point-source assumption and differential geometry theory. The proposed lens design method is straightforward, flexible, and effective. Moreover, the optical performance of the lens can be intuitively adjusted by tuning just a small number of design parameters. The simulation results showed that the proposed lens achieved an excellent collimating effect for a commercial ultraviolet (UV) LED. A prototype lens is fabricated in UV-grade poly(methyl methacrylate) material using a standard injection molding process. The light collimating effect of the lens/UV-LED assembly was measured experimentally and was shown to be in good agreement with the simulation results. The collimating angle at the half-energy level was equal to 1.88°. The performance of the UV-LED is thus comparable to that of conventional lithography UV light sources based on mercury arc lamps. Consequently, the proposed double freeform lens showed significant potential for photolithography applications within the industry.

Highlights

Compared to the traditional UV mercury lamps used in conventional photolithography systems, ultraviolet (UV) light emitting diodes (LEDs) have the advantage of having a lower cost, a reduced electricity consumption, a longer lifetime, improved stability, and being more environmentally friendly.As a result, there has been growing interest in it being a potential light source for UV lithography processes
As in the previous the designed double freeform lens was by Todescribed better understand the lightsection, collimating effect of the double freeform lens, formanufactured each ray reaching
This paper presented a double-sided freeform lens for collimating light emitted from a LED

Summary

Introduction

Compared to the traditional UV mercury lamps used in conventional photolithography systems, ultraviolet (UV) light emitting diodes (LEDs) have the advantage of having a lower cost, a reduced electricity consumption, a longer lifetime, improved stability, and being more environmentally friendly.As a result, there has been growing interest in it being a potential light source for UV lithography processes. Compared to the traditional UV mercury lamps used in conventional photolithography systems, ultraviolet (UV) light emitting diodes (LEDs) have the advantage of having a lower cost, a reduced electricity consumption, a longer lifetime, improved stability, and being more environmentally friendly. Collimating the UV light without losing too much of the light energy represents a major challenge and requires the use of special lens designs. Both primary and secondary optics are commonly adopted to adjust the distribution of light so as to meet the overall specifications and create the desired beam pattern. In particular, have been widely used to refract and/or reflect LED light. The authors in [1,2,3]

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