By BizLED Bureau
September 23, 2015: All types of LEDs are not suitable for automotive applications. For automotive applications, LEDs need to have longer lifespan, and to withstand harsh environmental conditions like extreme cold and extreme hot weathers, besides humidity, vibration, etc. Hence, the manufacturers of automotive LEDs need to make quality products and for that the industry needs to have new global standards.
Global standards are required to test automotive LEDs
To make LEDs suitable for automotive applications, these LEDs need to pass through specific tests before they can be certified for automotive applications. To test these LEDs so that they qualify different environmental conditions, special and expensive equipment like thermal chambers are required.
Test for semiconductor
Earlier, semiconductors for automotive applications were tested as per the standard developed by the Automotive Electronics Council (AEC), called AEC Q101. This standard is good for silicon-based semiconductors, but it does not test the light-emitting charecteristics like group-III-V compound semiconductors. So to solve this problem, effort was made by the International Electrotechnical Commission (IEC) to develop a better standard. Moreover, the new automotive lighting applications like driving beams in headlamps that are adaptive, increases the need for new standards. Despite AEC Q101 been updated to D-version, yet it cannot tests LEDs for automotive applications.
Next, a committee of the United States Council for Automotive Research (USCAR) started to develop a test for LEDs to get information about the failures of the LEDs.
IEC 60810 test
The International Automotive Lighting and Light Signalling Expert Group (GTB) developed a draft IEC document, which received a lot of support from as IEC committee and was approved by the IEC committee. The new LED test will be added as a part of the IEC 60810 standards, called “Lamps for Road Vehicles?Performance Requirements.”
Details of the new test
While, many AEC Q101 testing aspects were retained, many LED-specific criteria have been defined in the new test. The technical parameters were also monitored. For example, LEDs stressed under HTOL conditions were tested for luminous flux maintenance. The results showed that after 1,000 hours, the LEDs have luminous flux maintenance that is more than 90%.
Some of the aspects that need to be tested are power temperature cycling, wet high temperature operating life, temperature cycling, high temperature operating life, etc.
USCAR Lighting Group test
Meanwhile, the USCAR Lighting Group felt the need to develop a test to test the LEDs for exterior lighting of automobiles. So it developed “Specification for Testing Automotive LED Modules.” This is to test the over-stressed LEDs to ascertain the failure limits of the LEDs. The duration of the test about 1,500 hours and it tested all the components and the module to see if they are suitable to be used in the harsh environments.
Despite all these tests, a global standard is still necessary to define a systematic method to test automotive LEDs.