ACU improvement of CCT-tunable LED device by electrospun nanofiber film

We fabricated PMMA nanofiber composite diffusion films to improve the angular color uniformity (ACU) of correlated-color-temperature-tunable light emitting diode (CCT-tunable LED) device. Based on electrospinning technology, we prepared diffusion films with different scattering properties by controlling the fiber deposition time. Detailed optical measurement shows that the scattering intensity of PMMA nanofiber films increases with the increase of thickness. The diffuse transmittance and haze are 88%, 96.6% in the visible light, respectively. Furthermore, when applied to the CCT-tunable LED device, the device witnesses a reduced CCT deviation from 630 K to 159 K in a typical CCT range of 5000-6000 K. Therefore, the proposed nanofiber films can be applied to lighting systems as diffusion films to improve their ACU.