Liquid color: Flexible, angle-independent structural color from microdroplets

This invention uses microdroplets with particle arrays (“photonic balls”) to achieve angle-independent structural color. When incident light is reflected off the disordered arrangement of scattering centers in the microdroplets, only certain wavelengths are reflected back, giving the appearance of color. In this invention, the size and spacing of these scatterers can be independently controlled, allowing for fine tuning of the light reflected from these scatterers to produce pure, saturated colors of narrow wavelengths. The invention also allows for enhancement of colors (i.e. red) not typically seen in structural color devices. The color is high in efficiency and does not rely on filtering for color selectivity. The coloration can be achieved with a wide range of chemicals and could be incorporated into flexible, low-power reflective displays.

Additionally, unlike traditional (sometimes toxic) pigment-based colorants currently used for commercial cosmetics and paint products, structural color can create a wide range of colors while using a limited number of material chemistries. Thus, these “photonic balls” arrays could also be incorporated into paints and cosmetics to achieve a wide range of long-lasting colors with non-toxic chemicals.

Below are four examples of color droplets produced with this technique.

Light Blue

Dark Blue




The future breakthroughs in display technology are in reflective, color displays. The ideal display will be low-power, thin, light and flexible, producing bright colors with high contrast and high viewing angles. These parameters have not been met with traditional LCD/LED display technologies that are used in everything from televisions to cell phones. Current reflective display technologies are also either low in efficiency or do not have color capability. Thus, research into efficient reflective color display technologies is still ongoing. Structural color could be incorporated into the next generation of displays.

Intellectual Property Status: Patent(s) Pending