Monitoring LED temperature with thermal imagers

FLIR Systems has helped Belgian manufacturer Delta Lighting improve the durability of its lighting systems by monitoring the product temperature profiles.

Delta’s Light’s research and development team is focused on ensuring fire safety as well as improving the durability of its lighting designs. One of the most critical factors of durability is temperature. In order to better monitor the temperature profile of its products, Delta Light decided to purchase a thermal imaging camera from FLIR Systems, said Koen Dequae, Quality and Standards Manager at Delta Light.

Already familiar with the concept of thermal imaging, it didn’t take Delta Light very long to conclude that FLIR’s E30 handheld camera was a suitable fit for its application in terms of performance and cost-efficiency. 

“Monitoring the temperatures of our products is critical in the design, development and qualification phase,” said Dequae. 

“We now work with LED lights that have a lifetime of up to 100,000 h. If you realise that a temperature raise in the lighting system of a mere 10 degrees can reduce the LED lifetime by half, then you know that keeping the temperatures under control is essential.”

Delta Light uses the FLIR E30 camera to look at the LEDs, the electronic power supply of the lighting systems - both proprietary and third-party - and the temperature profile of the lighting system as a whole. The latter is essential to be able to design and manufacture lighting products in accordance with international (IEC-60598) and North-American (UL-1598) standards. 

“These safety standards stipulate that a lighting system design cannot exceed a certain temperature,” said Dequae. “To make sure that is the case, we look at the entire design and look for the hottest point. If that hottest point does not exceed that temperature, we meet the standard.” Thanks to the FLIR E30 camera, Delta Light can now perform these qualification tests in-house; the company no longer needs to rely on external agencies. That saves Delta Light a lot of time and effort in the qualification phase. 

The use of thermocouples is still required in order to meet certain international standards. However, these wired sensors have some significant drawbacks which make the work of research and development specialists difficult. 

“To meet the required safety standards for our products, we heavily rely on finding the hottest spot on our lighting design,” said Dequae. “However, with thermocouples that is not always very simple. Just by moving a thermocouple just a few millimetres on the lighting design, the temperature values can present significant differences. In other words, relying on thermocouples alone for temperature measurement is not sufficient. Only using thermocouples is like groping in the dark.”

A thermal imaging camera, on the other hand, provides more confidence. By using the camera, Delta’s research and development specialists have an immediate overview of the temperature values of the total lighting system design in the blink of an eye. This saves valuable time. 

“We also use the FLIR camera to look at our electronics designs,” said Dequae. “This helps us see overheated components and prevent bigger component failures. Try and put a thermocouple on certain SMD board components … It’s just not possible due to their small size. With a FLIR camera, we can see these temperature differences, also on the smallest printed circuit board components.” 

The FLIR E30 has quickly become an invaluable tool for Delta Light’s R&D team. Since its purchase, the camera has been used in the prototyping phase, the qualification phase and practically in any phase in between. 

“The camera gives us the speed and flexibility boost we need,” said Dequae. “When we are in the design phase of a lighting system, we can quickly use the FLIR camera to see whether a certain approach is feasible in terms of temperature build-up. But also in the qualification phase, the FLIR E30 allows us to see temperature profiles instantly, which would take hours with thermocouples.”

An increasing number of research and development specialists are discovering the benefits that thermal imaging has to offer. FLIR Systems can offer them a benchtop thermal kit (BTTK) that can help them with their research and design work. Each BTTK contains an entry-model thermal imaging camera, fixed-mount or handheld, and software. Thanks to these entry packages, thermal imaging is rapidly finding its way to more and more test benches.