How do you know you are choosing a quality LED?

The LED lamp market is growing steadily with sales expected to reach £600 million by 2018 and it is still a rapidly changing technology. LED’s have become extremely popular for both domestic and commercial applications, with huge growth in the retail sector. The only problem with LED lamps is that whilst they will save up to 80% in energy when compared to a traditional light source, they tend to look very similar to each other, irrespective of the quality of the components that have been used to make them. The trouble is, they may look the same but their performance can vary considerably. This may be in terms of the light output, consistency of colour temperature, energy consumption or the longevity of the lamp.

In many ways, this is potentially more of a problem with LEDs than other light sources because they are more complex than traditional lamps. For example, a typical LED lighting system comprises of a power supply that converts the mains voltage to a constant voltage, which is then supplied to the LED lamp. The role of the LED driver is to convert the mains supply into either a constant voltage or a constant current that is then supplied to the LEDs themselves. The constancy of the current ensures a constant light output, with the light output being proportional to the current applied.

An important point here is that energy is lost at each of the conversion stages described above and this can have a significant impact on the overall power supply efficiency. In fact, the power supply efficiency of LEDs from different manufacturers can vary from 50% to 90% and this will influence the overall energy savings that are achieved.

Also, the light energy generated by the LED is then converted to white light by exciting phosphors that coat the LED, in the same way that fluorescent lighting works. The quality and consistency of the phosphor coating has a direct impact on the consistency of colour temperature and colour rendering. There are huge advantages to be had for commercial lighting by getting the colour temperature right – mood can be increased and atmosphere created for hospitality, whilst the colours of merchandise can be highlighted in retail applications. Megaman lamps can achieve a warm temperature of 2400K for mood creation up to 5500K for colour enhancement in retail applications.  Megaman is now concentrating on improving the quality of light and the CRI not reducing the wattage.

While the factors described above apply to all LED light sources, there are also other considerations relating to retrofit lamps that are designed for fitting to an existing luminaire. For instance, the optical design of the retrofit LED lamp has a significant impact on overall performance.

In many retrofit lamps there are both primary optics and secondary optics. The primary optics are frequently built into the LED source, often in the form of a dome that helps to increase light output. There may then be secondary optics added to modify the beam width or light distribution, adding further to the complexity of the design and the intricacy of manufacture.

There is also the whole issue of thermal management as LEDs can generate a considerable amount of heat. If the temperature in the vicinity of the LED and its electronic circuitry is allowed to get too high this will both reduce light output and the life of the lamp. Retrofit lamps therefore have a built-in heat sink to conduct heat away from the sensitive electronics - so the efficiency with which the heat sink does its job is another important element in performance and reliability.

A lack of effective surge protection is also important, as is the use of a sealed housing to prevent moisture infiltration.

For all of these reasons it is clear that each of these components is important in the overall performance of the lamp that the end user experiences, thus reinforcing the importance of high quality manufacture using proven, reliable components.

Trusted brands

Given the complexity of LED lighting, as described above, the reasons for being very cautious when sourcing LED lighting products become immediately apparent. Megaman has addressed the issues above by launching product ranges using TCH technology (an ingenious highway design across the reflector to dissipate heat efficiently) for thermal control, instant start, smooth dimming, Perfect White and Dim to Warm. Megaman also use a ‘true size shape’ that allows easy retrofit and the process of ‘LEDification’ of the traditional light source formats is pretty much complete so there are now LED alternatives for the vast majority of lamp types.

Megaman’s Dim to Warm allows linear dimming from 2800K to 1800K, providing a perfect solution for many applications where it is desirable to change the ambience at different times of day. A cosy hotel bar is one obvious example of this. The fact that these lamps are available in candle, GLS, AR111 and GU10 formats also gives them very wide scope. Tuneable White allows commercial projects to choose between 3000K and 6000K so that users can tune the lighting to the shade of white they want, without needing to change light source, and dim it if necessary. Tuneable white lighting is ideal for multi-use areas or where there is a requirement to link to human-centric lighting systems. Perfect White which makes white clothes in retail look really amazing. This is a significant development because general LED lighting tends not to show plain white fabrics at their best, but by adding a violet spike to the phosphor mix their appearance is transformed.

Megaman is also producing fittings that meet the requirements of the hospitality and leisure sectors. Indeed, as the LED light source has become well established there has been a corresponding boost in the introduction of luminaires that have been designed specifically for LED light sources. This is a clear benefit as these luminaires are able to optimise the particular optical characteristics of LEDs to achieve maximum light output ratio and efficient light distribution. In parallel, the ability to use new thermoplastics in the manufacture of LED luminaires – something that couldn’t be done three years ago – is enabling luminaire designers to broaden their creative output.

2015 is set to be a very significant year for low-energy lighting in general, and LED lighting in particular. In order to achieve the maximum benefits available it is important to start thinking beyond simply swapping an energy-hungry light source for a more efficient one and begin to take advantage of the extra functionality that are now making possible. Additionally, Megaman has its own test facility and is able to subject its products to continuous assessment to ensure good quality control and consistent performance.