LED displays are getting hotter. With the introduction of more defined, brighter displays comes the use of more electricity and a greater degree of heat generation. Ensuring that these systems remain cool to prevent damage is now essential, and there are several ways of achieving that.
Heat sinks and the general shape of casings can improve heat dissipation. Understanding where the heat comes from and what problems high temperatures can pose LED systems is the first step towards tackling the issue.
In comparison to conventional lighting elements, the proportion of heat to light in LED lighting is significantly lower. However, the evolution of brighter LED lighting systems has come with expected heating issues; brighter lights and more electricity usage naturally mean hotter elements, even in LED systems.
The central semiconductor devices of LED systems are small, delicate components which are susceptible to heat damage at high temperatures.
Semiconductor junctions are the cause of overheating
Heat related issues with general lighting, away from LED systems, are to do with heat being produced as a by-product of light production, in LED systems this is not the case. The heat produced from LED systems stems from the semiconductor junctions. Masquerading as an efficient light producer, LED systems’ secret is that only 30% of the electricity used in creating light in LED systems is used to create light, the remaining 70% ends up as heat.
In normal lighting, such high levels of heat is not a serious problem; however LED systems in electronic devices such as laptops and mobile phones are tightly enclosed meaning ventilation can be difficult.
These tight, space saving, insulated enclosures can reach potentially damagingly high temperatures after several hours of consistent use. With LEDs moving into the 35W range it is becoming so important to avoid damage that systems like heat sinks are being put in place to channel heat away from components like the junctions and semi conductors which are vulnerable to heat damage.
Heat sinks provide a path for excess heat to follow from within the system to the outside where the heat can radiate away from the device. The thermal conductivity of the material used in the heat sink is vital. Aluminium and copper are the most commonly used metals in heat sink creation, copper having an advantage in LED heat sinks as it is more effective in a flatter form. These heat sinks are often stamped from sheets of these metals in a number of customisable shapes making them available for most LED displays.
If the heat dissipation is not foreseen to be a problem however, certain thermoplastics may be used, which are cheaper albeit less effective.
Liquid filled heat sinks allow for smaller solutions
There are developments being made in heat management. Most interestingly is the inclusion of liquid filled pipes in heat sinks to increase their thermal conduction capacity making smaller heat sinks more viable, allowing for smaller devices, which appears to be the direction the industry is headed.
Fan cooled computers are becoming a thing of the past, meaning that such methods are certainly not appropriate for the LED industry which prides itself on thin screens, allowing no room for fans.
The possibilities for software aiding heat dissipation are not significant. The potential for sensors to register when heat levels become critical responding by lowering the brightness of the system is a possibility.
Heat sink technology is expanding providing more efficient solutions to LED heat issues, hopefully making heat damaged systems a thing of the past.
Louisa Logan is a project manager within the electronics components industry. She specialises in LEDs and is enthusiastic about discovering thermal cooling solutions for her circuits and projects.