Method and apparatus using combination of quantum dot-containing films with optical filter films for signage and illumination applications

摘要

An illuminated sign includes a source of blue light (blue backlight, see Blue Excitation) and a quantum dot-containing sheet (QD Film) that emits green light and partially transmits blue light. The sign also includes a patterned blue-cutoff filter (grey areas of EXIT sign) which creates saturated green areas. Openings in the filter pattern (see white areas in EXIT sign) transmit blue light and green light which is perceived as a pseudo white light . The illuminated sign may thus have pseudo white letters and/or graphics on a luminous green background. The QD film may also include red-emitting quantum dots or a red-emitting phosphor. Blue light emitting diodes (LEDs) may provide the source of blue backlight. The illuminated sign may be an emergency exit sign.