Light source life (lamplife) light source life, also known as the light source life. The life of electric light source is usually represented by two parameters, which are effective life and average life span. 01, effective life: refers to the lights began to light up to the luminous flux of the lamp to decay to the rated luminous flux of a hundred points than experienced lighting number. Generally this percentage is between 70% to 80%. 02, the average life expectancy: refers to a group of test sample light from ignition to one of the 50% failures, experienced lighting hours. Life is the main technical parameter to evaluate the reliability and quality of electric light source. It has long service life, high durability and high power saving.
< p > luminous efficiency (2): ratio of the light emitted by the total luminous flux from the source consume electric power (Watts), known as the light efficiency of the light source. The unit is: LM / w (lm/w). This is the flux (Lumens):.

light flux (Lumens): a light source emits light in a unit of time is called the total luminous flux of the light source. Symbol: Phi, per lumen Lm. for example: a 40W ordinary white fabric lamp luminous flux for 350---470lm and a 40W ordinary straight tube shaped fluorescent lamp luminous flux is about 2800lm, white lights woven of 6-8 times.

The color temperature of < p > color temperature ColourTemperature: light emission light color and black body at a temperature radiation the same color, the temperature of the blackbody called the color temperature of the light source. Because most of the light emitted by the light all known as white, so light source color table temperature or the correlated color temperature is used to refer to the photochromic relative degree of expression of light and color quantization of the light source. According to MaxPlanck theory, with a completely absorbed radiation ability and the standard blackbody heating, temperature gradually increased in brightness change; CIE chromaticity coordinates of blackbody curve (Blackbodylocus) display blackbody by red - Orange - yellow - yellow white, white, blue and white of the process. Blackbody heating to the temperature and light are the same or similar color, defined with a correlated color temperature of the light source, the said color temperature, the absolute temperature and K (Kelvin, or open's temperature) units (k = C +273.15). Therefore, the blackbody is heated to red when the temperature is about 527 degrees Celsius or 800K, other color change temperature effect. The blue color, the color temperature is higher; reddish color temperature is low. The day painting color of light also varies with time: after sunrise 40 minutes of light color is yellow, temperature 3000K; midday sun white, rose to 4800-5800K, cloudy noon specific provisions about 6500k; before sunset light color reddish, color temperature and fell to paper 2200k. Color temperature of other light source. Because the correlated color temperature in fact to blackbody radiation close to the color of light source, the evaluation on the performance of the light source color value, a second light source is not a precise color contrast, so with the same colour temperature value may in color appearance is slightly different. Only the color of Feng could not understand the source of the object color, how to reproduce or objects in the light color. Different color temperature of light source, light color is also different, color temperature below the 3300K sedate atmosphere, warm feeling; color temperature in the 3000--5000K intermediate color temperature, a refreshed feeling; color temperature 5000K above have the feeling of cold.

< p > display color index colourrenderingindex: sunlight and incandescent lamps are radiation continuous spectrum, in the visible light wavelength (380nm-760nm), contains a red, orange, yellow, green, cyan, blue, purple, and so on all colors of light. Under the illumination of the sun and the incandescent lamp, the object shows its true color, but when the object is illuminated by a gas discharge lamp in the non continuous spectrum, the color will have different degree of distortion. The source of real object color presents the degree of said light source color to the color of light source for quantitative evaluation, introducing explicit concept of color index, subject to the standard light source, the color rendering index set at 100, remaining light source color rendering index were lower than 100. Color rendering index with Ra, Ra value is greater, the better the color of the light, the better