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The basic concepts and related parameters for LED

time:2020-06-22 source:ZJ Lighting Views:243

 In the 19th century, humans entered the age of electric lighting. After the development, now is the fourth generation solid light source --LED lighting era. Let's take a look at the knowledge of LED lighting.

  Glossary: LED is the abbreviation of Light Emitting Diode

  Based on the different semiconductor materials used,the emitting color for leds emit is different, traditionally there is red, green, orange, yellow, blue, etc. So it's going to be called a blue-ray LED.White light is a composite light, therefore the so-called LED white light is modulated on the basis of the above.

  The basic parameters for Lighting application :

  luminous flux

  Refers to the human eye can feel the radiation power, that is, the ratio of light emitted by the light source. The unit is LW (lumens). The nominal luminous flux of a 40 W incandescent bulb is 360 lm, the nominal luminous flux of a 40 W daylight fluorescent lamp is 2100 lm, and the luminous flux of a 400 W standard high-pressure sodium lamp is 48000 lm.

  luminous efficiency

  The ratio of Luminous flux and electric power, unit generally is lm / W. Luminous efficiency represents the energy-saving characteristics of the light source, which is an important indicator of the performance of modern light sources.

  Luminous intensity and intensity distribution

  LED luminescence intensity is a representation of its luminous intensity in a certain direction. Since leds differ widely in different spatial angles, it is necessar y to understand the light intensity distribution characteristics of LED.This parameter has a real meaning, which directly affects the minimum observation Angle of the LED display device.

  wave length

  For the spectral characteristics of LED, we mainly see whether its monochromaticity is good, and it should be noted that the main colors of red, yellow, blue, green ,white leds and other major colors are pure positive. Because in many occasions, such as traffic lights on the more stringent requirements of color, but according to the observation, some LED lights in green to blue, red to crimson, judging by the phenomenon we devoted the spectral characteristics of the LED is very necessary and meaningful.

  Color temperature

  The light that is seen by ordinary people is composed of a spectrum of seven colored colored lights. However, some of them are bluish, while others are reddish, Color temperature is a method that is used exclusively to measure and calculate the color components of light.The unit is K. The color temperature of the light source is different, the light color is also different, and the feeling is not the same:

  <3300K warm (with reddish white)

  3000-5000K middle (white) refreshing

  > 5000K cool (with blue white) cold

  CRI(color rendering index)

  The color rendering ability for an object from light source referred to as color rendering index,by comparison with the appearance color of an object under the same reference color temperature or reference light source (incandescent lamp or painted light). Color separation in two types, the one is faithful coloration, can accurately represent the original color of the material which needs to use a high color rendering index (Ra) of the light source, the value close to 100, the color rendering is the best. The another one is the effect of color, it is necessary to clearly highlight for specific color, The life of beauty can be used to enhance the color effect by adding color. Using low - color temperature source irradiation, can make the red color to be more vivid; Adopt medium color lukewarm light source illuminate, make blue with a sense of cool; high color temperature light source make the object has a cold feeling.

  The grade for color rendering Index (Ra) and general application

  90-100 1A excellent for the palce that needs with accurate contrast color

  80-89 1B for the place that needs correct judgment color

  60-79 2 Normal for the place that require Neutral color rendering index

  40-59 3 for the place that with less demanding of color rendering and less


  20-39 4 for the place with no specific requirements of color redenring index.