The colorshift is a change in the color temperature of an LED as a result of direct casting of the chip with (for example) resin. Due to a change in the refraction of light at the transition of the layers, this drift arises. There are various ways to prevent this effect: know and calculate the factor of the shift; avoid direct casting or chemically counteract the drift.
The variety of different circuit boards (rigid; flexible) is huge. All manufacturers have a different heat effect and therefore need costumized heat management. Whether hotspot, full surface or heat spreader – the right thermal management extend the life-time of your products. The path between necessity and overengineering to find is our target.
Chemical border relations
Very rarely do products consist of just one component – mostly, many materials come together, which then have to be cast. The circuit board usually has many different materials (soldering flux, solder, etc.), as well as cables (sheathing, etc.), carrier and sealants. In order to produce a homogeneous product, the components must be coordinated. Border relations, which can be the result of chemical reactions, happens often – but only at the customer’s side. A professional coordination of all components is not only important, it´s elemental.
With exothermic reaction we mean the heat effect by the chemical reaction of (for example) Polyurethane. Two chemical substances react without adding an energy by self-reaction to a new substance. (Polyaddition of polyol + isocyanate = polyurethane) The temperature increases as more material is mixed together. It is important to plan this temperature before products are designed. Most common epoxy, for example, have a temperature that can already damage components like the solder paste. Polyurethane usually has a heat of about 80 degrees.
Coefficient of thermal expansion
All materials have a specific coefficient of expansion. This should – for all components you used – be known and coordinated. For example, a plastic may have a coefficient of expansion that is ten times higher than aluminum. This creates tensions, tensions creates cracks, and cracks creates moisture damage. IP68 needs more!
...and much more!
We can´t say everything – but if you have any questions, we are happy to help. Take advantage of our knowledge!