Introductions of LED testing methods (2)

Using integrating method, LED lighting sources will automatically absorb rays, affecting the final results. In order to remove this influence, technicians need to use auxiliary lamps. Once obtained the luminous flux, we can use it to get the lighting efficiency of LED Lights. Testing methods for radiation flux and radiation efficiency are quite similar to luminous flux and lighting efficiency.

Using integrating method, LED lighting sources will automatically absorb rays, affecting the final results.

Light intensity and light distribution are two relatively complicated compare with other LED testing methods. Spot lighting sources have even light distribution in space. Sensors in different distances and using different apertures will have same results. However, the light distribution of LED STREET LIGHT is uneven. Measuring results will be various depending on measuring distances and diameters of apertures. Standard CIE-127 gives out a series of reference parameters in different measuring conditions.

The spectral parameters include peak wavelength, bandwidth and spectrum power distribution, etc. signal light LED only has one wavelength (spectral properties can only be presented by peak wavelength and bandwidth), while white LED spectrum is a combination of multicolored rays (spectral properties can only be presented by power distribution). We can also calculate color parameters though the LED spectrum power distribution. LED spectrum power distribution can be obtained though spectrophotometers, measuring various rays separately.

 

Switching feature of LED Products can be defined as the optical/electrical/color changing properties at the moment of power charge and power lose. Through them we can obtain the working conditions and physical attributes at these moments, helping us to learn the damages caused by opening/closing the switch to LEDs. Designers also can improve driver module though this parameters.

 

Color properties of LEDs include chromaticity coordinates, dominant wavelength, color purity, color temperature and CRI, etc. Color properties are rather important for white LEDs. Currently, there are two LED testing methods for color properties: Spectrophotometry and Integration. Spectrophotometry can analyze the LED spectral power distribution by using monochromator, then obtain the corresponding color parameters though Chroma Weighting Function. Integration method directly measure chromaticity in the use of specific filters along with photo detectors. Spectrophotometry is more accurate and more complicated than Integration method. Both of them need to measure color parameters with the aid of high-precision instruments. Scientists are looking for cheaper and more accurate methods.