Fast full‐color reflective display via photoluminescent enhancement

Reflective displays are advantageous in applications requiring low power or daylight readability. However, there are no low-cost reflective technologies capable of displaying bright colors. By employing photoluminescence to more efficiently use ambient light, we created a prototype display that provides bright, full color in a simple, low-cost architecture. This prototype includes a novel electrokinetic shutter, a layer that incorporates patterned luminescent red, green, and blue sub-pixel elements, and a novel optical out-coupling scheme. The luminescent elements convert otherwise-wasted portions of the incident spectrum to light in the desired color band, resulting in improved color saturation and lightness. This prototype provides a color gamut that is superior to competing reflective display technologies that utilize color filters in single-layer side-by-side sub-pixel architectures. The current prototype is capable of switching in <0.5 s; future displays based on an alternative electro-optic shutter technology should achieve video rate operation. A transflective version of this technology has also been prototyped. The transflective version utilizes its backlight with a power efficiency that is at least three times that of a conventional liquid crystal display. These photoluminescence-based technologies enable a host of applications ranging from low-power mobile products and retail pricing signage to daylight readable signage for outdoor advertising segments.