Pseudo‐natural Light for Displays and Lighting

Abstract

Light quality shows strong effects on humans in many aspects, including aesthetics, psychology, physiology, and health. By assuming that natural light has the best light quality, devising a pseudo‐natural light is hence important and critical. Here, an all‐weather pseudo‐natural light is demonstrated based on a high number of broad‐band emitters. By doping six broad‐band organic light‐emitting dyes in three separate emission layers, for example, the light source can exhibit a 92–96% similarity with the sunlight from dawn to dusk, and a color gamut of 80% in terms of NTSC. By combining six narrow‐band light‐emitting diodes (LEDs), a much wider gamut of 121% NTSC is achievable, but with a slightly poor daylight similarity, i.e., ranging between 80% and 83%. The daylight similarity, however, can easily be enhanced to at least 94% upon incorporating broad‐band phosphors, even with the use of only one or two LEDs.

Plant Growth Absorption Spectrum Mimicking Light Sources

“…Among these, OLEDs can closely mimic almost any natural light with any desirable color [30]. The resultant OLED device shows to be an ideal light source for plant growth, as confirmed via the theoretical calculations.…”

P‐145: Blue Light Hazards and Methods of Quantification

“…For example, the low pressure sodium lamp has a CRI value of -12. [19] As in terms of SRI, the light quality index is 31 for the low pressure sodium lamp. Although the light quality is poor, relatively, low pressure sodium lamps are widely accepted as street light for being energy-saving.…”

Scotophase interruption with LEDs and OLEDs to inhibit photoperiodic induction of diapause in Tetranychus urticae and T. kanzawai (Acari: Tetranychidae)

“…Partially supplemented blue LED promoted stem and internode elongation growth without any inhibitory effect on flower bud formation of a chrysanthemum, Chrysanthemum morifolium Ramat (Jeong et al 2014). Furthermore, OLEDs closely mimicked natural lights with desirable colors and functions as ideal light sources for plant growth (Jou et al 2015). Therefore, OLEDs might contribute to high efficiency in plant cultivation systems within a few years.…”

“…Scotophase-interrupting experiments on mites have long been conducted to investigate the photoperiodic response of diapause (Lees 1953;Hussey 1972;Shah et al 2011b), but diapause inhibition under different light qualities (colors) and intensities has not been investigated. Light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs) are new light sources that are expected to replace conventional "vacuum system" light sources, e.g., incandescent lamps, fluorescent tubes, and high-intensity discharge lamps (Jou et al 2015). Compared with LEDs, OLEDs can be made to be extremely thin, small, and remarkably flexible-they are composed of organic compounds that light up when fed electricity (Karzazi 2014).…”

“…In particular, LED technology has been put to practical use in plant production systems because of its capacity to produce various colors of monochromatic lights, and to closely and uniformly irradiate plants. OLED technology may be used in plant cultivation systems within a few years (Jou et al 2015). Different spectral combinations can also affect plant growth and development (Barreiro et al 1992).…”