Methods and apparatus for transparent display using scattering nanoparticles

Abstract

Transparent displays enable many useful applications, including heads-up displays for cars and aircraft as well as displays on eyeglasses and glass windows. Unfortunately, transparent displays made of organic light-emitting diodes are typically expensive and opaque. Heads-up displays often require fixed light sources and have limited viewing angles. And transparent displays that use frequency conversion are typically energy inefficient. Conversely, the present transparent displays operate by scattering visible light from resonant nanoparticles with narrowband scattering cross sections and small absorption cross sections. More specifically, projecting an image onto a transparent screen doped with nanoparticles that selectively scatter light at the image wavelength(s) yields an image on the screen visible to an observer. Because the nanoparticles scatter light at only certain wavelengths, the screen is practically transparent under ambient light. Exemplary transparent scattering displays can be simple, inexpensive, scalable to large sizes, viewable over wide angular ranges, energy efficient, and transparent simultaneously.

What is claimed is: 
     
         1 . A transparent display comprising:
 a transparent substrate;   at least one light source, in optical communication with the transparent substrate, to illuminate the transparent substrate with light comprising a first spectral component at a first wavelength and a second spectral component at a second wavelength; and   at least one nanoparticle, disposed on and/or within the transparent substrate, to scatter the first spectral component and the second spectral component and to transmit ambient light at other wavelengths in the visible spectrum.