Researchers at the University of Michigan have developed angle insensitive spectrum filters for display and imaging systems. Color filters based on photonic and plasmonic crystal based structures have been proposed as replacements for colorant-based pigmentation display technologies. Nanostructure-based color filtering offers increased efficiencies, lower power consumptions, slimmer dimensions, and enhanced resolution. However, incident angle tolerance remains an open challenge.
The spectrum filters for display and imaging systems designed at the University of Michigan are characterized by the filtered spectrum being independent of, or insensitive to, the incident angle. Spectrum filtering and angle insensitive behavior is achieved by coupling light into arrayed nanoscale photonic resonators via light funneling. A grating structure is used to increase the transmission or reflection efficiency. Furthermore, the design is applicable to any transmission- or reflective-type flat panel display, especially for high input power applications, for example, 3D projection displays. The design of the thin film structure can simplify the color filter fabrication, and recycle the reflected light for overall higher transmission efficiency. Since colored pixels can be made smaller than the diffraction limit, superpixels can be used to mix different colors.
- LCD and 3D projection displays
- Colored e-books - Pigment-less and chemical-less colored prints
- Anti-counterfeiting and cryptographic applications
- Simplified color filter fabrication
- Increased transmission efficiency
- Superpixels can be used to mix different colors
- Long lasting colors
- Low power consumption
- Slim dimensions
- Enhanced resolution