LED Basic parameters
In lighting field, the application of LED lighting product is attracting the eyes of world. As a green lighting product of new style, it’s inevitable trend of future. LED is known as the fourth lighting source or green source, with the features of energy saving, environmental protection, long life, small size and so on ,widely used for many field such as indicates, display, decoration, back light, general lighting ,roadway lighting and night scene of city etc. Then which parameters for LED?
1, （Ra）Color Rendering Index (Ra)
It's a measure appeared for parameters of real color by object lighted. Color Rendering Index (0-100), the CRI is higher then the light color reappeared is closer nature primary color.
2, Luminous Efficiency (η)
The efficiency of the light source transfer electronic energy to visible light, it's the light out by light source consumption per watt, the higher of number showed the higher of light efficiency .In economic terms, the luminous is a important parameter. Unit: LM/W, The Luminous Efficacyη=Luminous Flux(Lm)/Power Consumption(w).
3, Luminous Flux (φ)
The summation of energy that light source launched and received by eyes. Unit: Lumen (Lm).
4, Illumination (E)
The Luminous flux by accepted by unit area. If the accepted luminous flux is 1LM of 1 square, so the illumination of work-plane is 1 Lx. Illumination E= the luminous flux of work-plane (Lm)/the area of work-plane (㎡)
5, Light Intensity
Radiance is the amount of light that passes through a particular area, and falls within a given solid angle in a specified direction (Unit:cd)
6, Brightness
The brightness of a point on a surface is the luminous intensity in a given direction with the surface area divided by the orthogonal projection ratio (Unit: cd/㎡)
7, Color Temperature
Color of the light source is the same to the color of an ideal "black body "emitting light in a certain temperature. The temperature of the "black body "called the color temperature of this light source. When the temperature of “black body" is higher, the light spectrum has more part of blue color, and the less part of red color. (Unit: K)
8, Glare
Discomfort in the eye and depression of central vision produced when a bright light enters the field of vision, particularly when the eye is adapted to dark. Glare is a light pollution, Glare produced due to the improper choice of light source, lamps or light source not match up the lamps.
9, Power Factor
It is the ratio of active power and apparent power. Apparent power is equal to active power plus reactive power .If the Power Factor is low, the power wastage is big, and it would destroy the balance of power network, and the high load of harmonic is a pollution of power network.
10, Average Life Span
It's the time of 50% damage
11, Electromagnetic Interference
It's the interference passed by radiation, conduction for other electronic equipments around, during operation of the ballast of gas discharge lamp.
12, Luminous Decay
With the time postpone, the luminous flux drop off during the light source using.
13, Harmonic
It’s would generate the polluted and harmful wave to power network, when The electronic ballast change the power frequency (50/60HZ) into Alternating Current above normal frequency. The harmonic content is show the harmonic less or more. The Standard requirement of harmonic content is level H and level I. Level H: The first harmonic <5%, the first harmonic <37λ%. Level I: the first harmonic<5%,the first harmonic <30λ%. And with request for the harmonic content of the third, fourth……forty times.
14, Stroboscopic Effect
The luminous flux of electronic light source changes along with the change of periodic variation of alternating current power supply, with the phenomenon of visual fatigue or visual illusion called Stroboscopic Effect. It's measured by fluctuation depth. The bigger the fluctuation depth, the more serious the stroboscopic indicated. The study showed, when the fluctuation depth >25%, will harm the health, when the fluctuation depth <60%, the human eye not feel, but still harm the health.
