Currently, our quality requirements for the LED is higher and higher, so we need testing on the LED. Following are seven elements that effect LED spectrophotometric and color separation:
1. The Chromaticity coordinates x, y step: for white or monochromatic light, chromaticity coordinates can be used to express in which LED area the LED is. Generally, 4 chromaticity coordinates define a chromaticity areas. And we need to do a couple of tests to ensure whether the LED falls in the right chromaticity area.
2. The luminous flux: the luminous flux value is always an indicator that LED users are very concerned by which the LED application client can know in which range of LED luminous flux they are using, so as to ensure that their products’ brightness uniformity and consistency.
3. The reverse leakage current test: reverse leakage current is lower than the required value when load a certain voltage. The high LED reverse leakage flow caused by static electricity, the chip quality factors in the production process will give great hidden trap in LED application productions and is very easy to cause the LED lamp to death when after using a period of time.
4. The main wavelength step: for monochromatic light LED, dominant wavelength is one of the most important indicators to measure its color parameters which directly reflect the human eye visual perception of the LED light.
5. Color rendering index step: color rendering index is very important parameter for LED lighting products which is directly related to the degree of color change of light reflect on the object.
6. The relative color temperature step: for white LED, color temperature one of the most used parameters as the manifestations of its color, which can directly present wheater the LED color slants warm, cold or white.
7. VF forward voltage test: the scope of the forward voltage should be within the scope of the licensed circuit design, many clients design drive light-emitting tube by battery voltage mode, forward voltage size will directly affect the whole circuit parameters which can bring hidden trouble to the product quality. In addition, some of the products which have requirement in circuit power consumption wants to under as lower the forward voltage is as better when ensured the same luminous efficiency.
In view of the above points, we can use two kinds of solutions for effective testing, one of the testing is from the voltage to the leakage current to the luminous flux to the spectrum with multi-channel process coordinated the quality controls and step by a lot of artificial. The other is automatically divide class through professional high-power LED testing machine which is high efficiency, fast speed and can be done for each LED spectral color separation.