Design of side-lit lightguides with inkjet-printed color-conversion structures

Display backlights typically rely on phosphor-converted white LEDs whose broad emission spectrum limits efficiency and color-saturation. Quantum dots (QDs), owing to their narrow emission bandwidths and high photoluminescent quantum yields, offer a promising alternative when excited by blue LEDs. Current QD implementations involve a QD-polymer film positioned above a lightguide illuminated by blue LEDs. This approach requires a large quantity of QDs and provides modest efficiency gains. In this work, ray-tracing simulations are used to design and optimize a side-lit lightguide integrating spatially patterned red, green, and scattering microstructures directly on its surface, which can be realized using inkjet-printing techniques. An iterative two-stage algorithm optimizes luminance and color uniformity by coupling light extraction and color conversion. Simulation results show that the patterned QD lightguides achieve high luminance and color uniformity while significantly reducing QD usage compared to conventional film-based designs, enabling efficient and spectrally tailored backlights for next-generation displays.