|CIE chromaticity diagram.All possible color coordinates(x,y)are on or indide the horseshoe curve.Pure colors lie on the curve, whereas the white point has the coordinates(1/3,1/3)
Luminous flux, :
Amount of radius energy visible to the human eye emitted by the light source.
Unit:absolute temperature (Kelvin, K)
The Color Temperature of a light source is defined as the absolute temperature of the standard “black body radiator” that emitting the light of the same color; a corresponding point can be plotted on the Plank Spectrum of color intensity.
Higher than the temperature on the standard black body, the light it radiates has more blue content and less red content. Take the common soft white incandescent lamp as an example, the color temperature is 2700K;while that of the daylight fluorescent lamp is 6000K,
The “Light Color” of a lamp can be categorized by its color temperature.
Three major “Light Colors” are:
Warm color: <3300K
Medium color: 3300 to 5000K
Daylight color: >5000K
Even having the same Light Color, different lamps very in color rendering because they emit the light with a different spectrum composition.
The set of light waves are distributed according to the order of wavelengths.Each light source has a Power Spectrum Distribution in the Light Spectrum.Power Spectrum Distribution of the sun or an incandescent lamp is a continuous curve, while that of a common electric-discharge lamp is not a
Light Emitting Diode(LED):
LED is a p-n diode made of specific materials. Under a positive bias,the electrons flow across the joint face, in the process of re-joining and disappearing, they emit light. Small in volume and low in Luminous efficacy, yet in the recent years LEDs developed rapidly and the application is setting
foot in the fields of traffic light, indicators, and even lighting of some special occasions.