Solution of light attenuation caused by high temperature

There are two methods to solve the light attenuation caused by high temperature, one is the design of thermal channels, and the other is to use materials with better thermal conductivity.

Design of thermal channels

As the name suggests, the design of a hot channel is to design a channel that is more conducive to dissipating heat so that the heat can be quickly discharged or cooled.

Basically all vehicles are equipped with a center grille in front of the front. The center grille design actually uses the airflow during the driving process of the vehicle to take away the heat in the engine compartment. It is a relatively reasonable heat channel.

Adding a fan to the LED headlight is actually similar to the central grid, but the high-temperature light of the PN junction relies on the fan, and the thermal conductive glue cannot be transmitted to the fan. Among them, the requirements for thermally conductive materials are good, and there is no problem with heat dissipation. It is futile if the heat conduction is not good.

So, how do we tackle the issue of light decay caused by high temperatures? There are two main methods: designing effective heat pathways and using materials with excellent thermal conductivity.

I look forward to delving into the detailed explanation of the hot channel design in the next article, as well as providing recommendations for three materials known for their excellent thermal conductivity.

Heat dissipation substrate

The most direct contact with lamp beads is the substrate and lens. However, the lens obviously has no way to conduct heat. Only by choosing a substrate with better thermal conductivity can the difficult heat dissipation task be completed. Currently, the substrates used by LEDs are generally divided into: aluminum substrates, ceramic substrates and double-sided copper substrates. Which of the three substrates is more suitable for use in automotive LED headlights? You can first look at their respective advantages and disadvantages.

Ceramic substrate

Advantages: The thermal conductivity of aluminum substrate is nearly a hundred times higher, it is resistant to high temperatures and has strong mechanical strength.

Disadvantages: The current domestic production capacity is not enough to supply such a huge industrial chain as LED.

Aluminum substrate

Advantages: Compared with epoxy resin substrates, metal substrates are significantly more reliable, have better stability, and excellent thermal conductivity.

Disadvantages: An insulation layer needs to be made before it can be put into use, and the overall thermal conductivity is still determined by the insulation layer. The thermal conductivity is about 2-3W/(m·K). Unless thermal and electrical separation is carried out, the whole process is somewhat outweighed by the costs in terms of process costs.

Double-sided copper substrate

Advantages: It can achieve efficient heat dissipation and super light concentration, and the thickness in the middle is very close to that of halogen filament; double-sided copper is more superior and has been regarded as the development direction of automotive LED lights in the future. LED headlight copper strip heat dissipation is a passive heat dissipation method. The larger the copper strip heat dissipation area, the better the heat dissipation effect.

Disadvantages: Expensive.

Summary

The above contrast is obvious. Whether metal substrates will be replaced by ceramic substrates, double-sided copper substrates are the development direction of LED car lights. They are still one of the best substrates on the market, and the price will naturally not be cheap. When buying LED car lights, riders must pay attention to their ability. In terms of brightness, if it is not a color-changing lamp, try not to buy a color temperature greater than 7000K to avoid insufficient penetration.