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[c 1] The photopic includes the CIE 1931 standard [c 2] (solid), the Judd–Vos 1978 modified data [c 3] (dashed), and the Sharpe, Stockman, Jagla & Jägle 2005 data [c 4] (dotted). The horizontal axis is wavelength in nm. A luminous efficiency function or luminosity function represents the average spectral sensitivity of human visual ...
An LED begins to emit light when more than 2 or 3 volts is applied in the forward direction. The reverse bias region uses a different vertical scale from the forward bias region to show that the leakage current is nearly constant with voltage until breakdown occurs. In forward bias, the current starts small but increases exponentially with voltage.
As illustrated by a straight line on the chromaticity diagram, simple two-white blends will have a pink bias, becoming most severe in the middle. A small amount of green light, provided by another LED, could correct the problem. [41] Some products are RGBWW, i.e. RGBW with tunable white. [42] A final class of white LED with mixed light is dim ...
Not all wavelengths of light are equally visible, or equally effective at stimulating human vision, due to the spectral sensitivity of the human eye; radiation in the infrared and ultraviolet parts of the spectrum is useless for illumination. The luminous efficacy of a source is the product of how well it converts energy to electromagnetic ...
A 230-volt LED filament lamp, with an E27 base. The filaments are visible as the eight yellow vertical lines. An assortment of LED lamps commercially available in 2010: floodlight fixtures (left), reading light (center), household lamps (center right and bottom), and low-power accent light (right) applications An 80W Chips on board (COB) LED module from an industrial light luminaire, thermally ...
The human eye can only see light in the visible spectrum and has different sensitivities to light of different wavelengths within the spectrum. When adapted for bright conditions (photopic vision), the eye is most sensitive to yellow-green light at 555 nm. Light with the same radiant intensity at
Non-SMD types of LED lighting also exist, such as COB (chip on board) and MCOB (multi-COB). Surface-mounted device LED modules are described by the dimensions of the LED package. A single multicolor module may have three individual LEDs within that package, one each of red, green and blue, to allow many colors or shades of white to be selected ...
Reverse bias: Although the LED is based on a diode junction and is nominally a rectifier, the reverse-breakdown mode for some types can occur at very low voltages and essentially any excess reverse bias can cause immediate degradation, and may lead to vastly accelerated failure. 5 V is a typical maximum reverse bias voltage specification for ...