| dc.description.abstract | Since the LED light emitting characteristic is strongly direction oriented and could be
causing the strong glare effect, the optical design of LED lens is necessary for
improving the lighting energy distribution in the areas of interest and reducing the
uncomfortable glare effect for the general illumination applications. In this dissertation,
the novel transparent plastic optical lens would be designed by using the free form
surface and scattering surface technologies. First, using the precise mid field angular
distribution model of the LED light source and the optical scattering surface property
of the Harvey BSDF scattering model and performing the optical simulation to develop
and design a novel plastic high transmission optical thick solid lens with free form
inner surface to achieve the optical performance of 89.89% light energy transmission
optics for the sake of energy saving reason, the 70 degrees angular light distribution
pattern defined at full width half maximum (FWHM) light energy level, and the optical
utilization factor of 51.8 % within -45 degrees and 45 degrees range in the areas of
interest with glare reduced for the down light illumination. Secondly, the free form
optical quasi-lens surface technology was utilized to develop and design a new solid
transparent plastic optical lens for the LED down light with the narrow angular light
distribution requirement in the LED lighting applications. In order to successfully
complete the mission, the precise mid field angular distribution model of the LED light
source was established and built. And also the optical scattering surface property of
the Harvey BSDF scattering model was designed, measured, and established. Then, the optical simulation for the entire optical system was performed to develop and
design this solid transparent plastic optical lens system. Finally, the goals of 40 degrees
angular light distribution pattern defined at full width half maximum (FWHM) with
glare reduced in the areas of interest and the optical performance of nearly 82% light
energy transmission optics were achieved for the LED down light illumination. Thirdly,
the goal of designing and developing a novel plastic optical thin piece lens couple
consisting of a plastic inner thin piece lens with free form optical scattering surfaces
and a plastic outer thin piece lens with an aspherical optical scattering front surface
was to match or exceed the optical performance with the angular light distribution
pattern defined from the previously designed plastic optical thick solid lens. With the
precise mid field angular distribution model of the LED light source and the optical
scattering surface property of the Harvey BSDF scattering models established, both the
performance of 91.92% light energy transmission optics of this novel plastic optical
thin piece lens down light and the optical utilization factor of 55.73 % within -45
degrees and 45 degrees range in the areas of interest with glare reduced were achieved.
Besides the above optical performance achieved, the production rate of the plastic thin
piece lens couples was raised to be 16 times higher than the production rate of the
previously designed plastic optical thick solid lenses. Moreover, the total costs of
producing one plastic thin piece lens couple were calculated to be only 10% of the total
costs of producing one plastic thick solid lens. With both the above advantages of
much higher production rate and much lower costs for producing this plastic optical
thin piece lens couple, the feasibility of the massive production purpose was highly
promising and practical to be achieved for the general LED illumination. | en_US |