In this paper we design a freeform lens according to the LED light distribution curve so that the light rays emitted from a
LED through the lens can achieve high uniformity and efficiency on the prescribed target plane. Because the model is of
rotational symmetry, we consider just a 2-D lens shape and then sweep to get the 3-D result. Here a procedure based on
the Snell's law and edge-ray principle for designing the freeform lens is proposed. First of all, we analyze the LED
intensity distribution and subdivide it into parts. Then we calculate the zones on the target plane where the subdivided
light rays should be distributed to. Finally we use an approximate analytic method to construct the freeform lens. After
constructing the freeform lens, we simulate for the optical model by using the ray-tracing software LightTools®. The
simulation results show that the Cree XLamp XR-E LED light source through the freeform lens can achieve up to 94.8%
uniformity and 89.1% efficiency including Fresnel losses for a 1 m distance away and 1 m radius of circular illumination
plane.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.