What Method Should Be Used to Test LED Test Items?

In recent years, performance testing technology and test equipment for LED products are developing rapidly in the world. With the improvement of testing technology and innovative ability for equipment, a series of advanced testing equippment have emerged in the market. Especially for LED photometry and energy efficiency tests, spatial light distribution test, accerated life test, optical radiation test and other tests, advanced testing equipment and LED measurement system have been developed, which are highly competitive on global market scale.

1. LED product metering and energy efficiency testing

The beam directivity of some LED products is very strong. In tests applying integrating sphere, the beam projection area and screen position are very sensitive. According to IESNA lM79 standard and CIE 127 technical report, hyperspectral reflective sphere inner coating material is recommended. NIST of the United States has launched the International LED Test Method Standards, which leads the world; it also comes with higher requirements for test equipment.

2. LED lights and lamps space light distribution test

LED goniophotometer is a light measurement device to measure the light intensity distribution of light sources and space. The principle structure of the rotating mirror goniophotometer is that the rotating mirror rotates around the central axis. It can precisely set a series of stray light apertures between the rotating mirror and the photometric detector to eliminate stray lights effectively. The LED goniophotometer is suitable for measuring the spatial light distribution of various complex beams. It has been adopted by more than 100 laboratories in the world, and the number of it applied ranks first. The rotating mirror goniometer is also employed in several national laboratories in China.

3. Photobiological radiation safety test and evaluation of LED products

With the development of photobiology, people pay more and more attention to the optical radiation safety. Especially with the rapid development of LED in recent years, the power and external quantum efficiency of LED chips have been greatly improved; high voltage blue LED chips are widely used in the field of general lighting; development of high-voltage multi-chip integration and the second optical technology draw more attention to the radiation hazard of LED lights. The safety of optical radiation for retina needs to measure 300 nm~700 nm blue light photochemical damage and 380 nm~1400 nm thermal hazards spectral radiance. 

4. Accelerated life test of LED

The service life of LED products can reach tens of thousands of hours. Much attention has been paid to evaluation of the service life of LED products in LED industry. The feasible method is accelerated thermal test based on LED junction temperature. Americaqna LM-80 standard provides three test temperatures: 85 ℃, 55 ℃ and customized (25 ℃). Under these temperatures, the LED light attenuation curve can be obtained, and the test takes 6000 hours.