Luminous flux Luminous Flux: Unit: lumen (lm)
The amount of light emitted from the light source in the unit time is called the sum of light flux.
Luminous Intensity:Unit: candela (cd)
Light flux at a given direction per unit solid angle emitted from the light source referred to in the direction of the luminous intensity, referred to as light intensity.
Illuminance: Unit: Lux (lx)
Illumination light source is in flux per unit area of the illuminated object.
Brightness Luminance:Unit: candela per square meter (cd / m 2,), (nt) is the old name of the brightness of the unit, now without repeal.
Brightness light source in one direction when the light intensity and the light-emitting surface in the same direction than the projected surface area of the light in that direction.
Luminous Efficacy of Light Source:Unit: lumens / watt (lm / W)
The total light flux emitted by the light source with the electric power consumed (W) ratio, called the luminous efficiency of the light source.
Average Life:Unit: hours (h)
It refers to the number of lamp ignition, when the number of hours in which 50% of the damage lamp does not light when lighted.
When the color of the light source with the blackbody emitted radiation at a temperature of the same color, the blackbody temperature is called the color temperature of the light source, expressed in absolute temperature K (kELvin).
Blackbody radiation theory is built on the basis of thermal radiation, so a kind of thermal radiation incandescent light source spectral power distribution of blackbody spectrum in the visible region of the power distribution closer, are continuous spectrum, with the concept of color temperature can describe this class color characteristics of the light source.
CCT-Correlated Color Temperature:
When the color of the light source with the blackbody emitted radiation at a temperature close to the color of the blackbody temperature is called correlated color temperature of the light source, the unit is K.
Since the gas discharge lamps are typically non-continuous spectrum, blackbody radiation with continuous spectrum can not be completely consistent, so we are used to approximate the correlated color temperature describing its color characteristics.
Color temperature (or correlated color temperature) below 3300K light source, reddish color, giving a warm feeling. Color temperature exceeds 5300K, partial color blue, giving a feeling of cold. Generally higher temperature areas, people use more color temperature higher than 4000K light source, while the lower temperature region is more or less with a 4000K light source.
(Ra) Color Rendering Index:
Sunlight and incandescent lamps are radiation continuous spectrum in the wavelength of visible light (380nm-760nm) in the range, including the red, orange, yellow, green, cyan, blue, purple and other shade. Object under illumination of incandescent light and the sun, showing its true colors, but the next object in a non-continuous spectrum of a gas discharge lamp light, color will have different degrees of distortion. We light the true color of the object is called the degree of color rendering light source.
In order for the color of the light source for quantitative evaluation of the introduction of the concept of color rendering index. Subject to the standard light source, its color rendering index is set to 100, the other light sources color rendering index of less than 100. CRI with Ra represents, Ra larger the value, the better the color of the light source.