Some people believe that all LEDs are created equal! After all there is a world full of manufacturers and suppliers from Asia and China in particular providing low cost solutions. It may then be a surprise for some people that there are only a handful of high quality LED manufacturers in the world.
In many applications it is sufficient to use lower quality LEDs but don’t expect to get a long life from these. High quality LEDs are required for consistent and reliable operation, in regard to output and long life.
So how do we tell a good quality LED from an inferior one? Selecting a good LED begins at chip level and ends with assembly.
Commercial quality grade 1 LED manufacturers use quality materials to produce superior, consistent wafers and chips. The chemistry and materials used during the wafer process are important variables in determining the overall performance of the LED. A good chip manufacturer produces chips with the fewest inconsistencies in colour, intensity and voltage drop.
Superior LED manufacturers are distinguished not only by the quality of their chips but also by their ability to sort LEDs into various bins based on colour, intensity, voltage drop and viewing angle. High quality LED suppliers offer customers consistent operating characteristics while lower quality manufacturers offer a ‘mixed bag’ of LEDs.
Beyond the LED itself,, the assembly and electronics supporting an LED are just as important to the performance, brightness and colour of the LED. Since ambient heat, operating currents, circuit design, voltage spikes and environmental factors can all affect the final performance of the LED chip. It is critical that product assembly and circuitry are suitably designed to protect the LED and ensure its performance.
Photos showing the cooling fins required on a 40w LED on the left and a 150w on the right.
With the rapid increase in demand for LEDs, the number of manufacturers and assembly designers serving the world market has likewise increased rapidly, with the end result that suppliers have flooded the market with low quality LEDs, but inexperienced packaging and design engineers. OEM manufacturers must test the circuitry and the LED assembly to ensure that design specifications are being met and the design provides for adequate heat dissipation as heat is a major cause of LED failure and inconsistent performance.
Accelerated life testing can be a critical element in avoiding failure in a specific application, as it can help ensure that you will not be surprised by premature dimming or fading after only 1000 hours or less of operation.
This can happen because low quality LEDs or even high quality LEDs in poorly designed assemblies can begin to dim and fade. In fact a low quality LED may initially appear brighter than a high quality one because it can have a higher drive current. However the extra current causes the LED to heat up more quickly and ultimately fade or burn out.
Generally LED lamps should not be used in enclosed fittings as the heat build-up will ultimately degrade the lamps performance and lead to premature failure. There are however, LEDs that are designed for this purpose but they are few and far between.
This is one example of where assembly has more impact on the LED performance than a chip itself. Some quality LED suppliers will guarantee their assemblies for two or more years, adding further verification that the end product contains a quality LED and is suitably designed for that specific application.
Hopefully you may find this information is helpful to you in deciding which LEDs to buy. Unfortunately, it is very difficult for the average person shopping for LED Lights to make a judgement call on what is a quality product and what is not. However, as a yard stick, you pay for what you get!
If you would like more information about what type of LED is right for your home or office, please contact us.