LED lighting is becoming ever more popular in industrial plants and facilities. What are the strengths and the possible criticalities of this technology for manufacturing areas? We asked Andrea Banfi of Lumileds.
Andrea Banfi explained to us: “LED technology represents a total rupture with the past in terms of lighting sources of which the limits are well known. Today, we expect completely different performance levels from LEDs, including longer life: the usual 50,000 hours have now been increased to 100,000 and even more. It is a figure that is derived from the mathematical calculations carried out in lab tests. It is certainly a valid criterion, but it should be verified against the actual conditions in which the LED is used.”
What are the factors that can put the operation and life of LEDs at risk?
“In the production of LEDs, manufacturers had to face different problems. During their manufacturing process, LED bulbs are subjected to thermal and chemical stress, because the electronic components must be assembled. During the welding, the peak temperature can be of even 260° C, which the LED will no longer reach during its lifetime. LEDs are also subjected to chemical stress due to the substances used during the welding, leading manufacturers to choose the most resistant material that can withstand these factors. For example, the plastic support of power LEDs has changed from a plastic material to a ceramic material because it is extremely resistant to heat and almost fully chemically inert.
To protect the phosphor that is fundamental for converting the blue LED into white light, the material that best reacts in terms of optical stability is silicone. Despite being extremely resistant to heat, chemical agents and oxidation, silicone is permeable to some chemical agents such as VOC (volatile organic compounds). Some of these substances may already be present in the manufacturing process, while others may be found in the environment where the LED will be installed, such as for example in the varnishing paints of some manufacturing plants, in which – even if they are mostly eliminated by suction hoods – the vapours tend to accumulate upwards towards the ceiling where the lights are installed.
These chemical agents penetrate the silicone and oxidise or break down under the effect of the blue radiation usually resulting in a thin dark layer covering the phosphor film, altering the LED performance in terms of emitted light output and white colour quality. It should also be noted that these substances are eliminated by oxygen, so the exposure to air makes them evaporate. In fact, if we allow browning LEDs to operate outdoors they will tend to recover partly or totally their brightness in some hundred hours.”
So how can we protect the LED?
“Therefore, the best way to protect LEDs is to either seal it completely or leave it exposed to the open air.
In the first case, we need to make sure that the material used to seal the LED is chemically compatible, even at high temperatures, in order to prevent the alteration process. Moreover, we need to pay attention to the encapsulant that will prevent air from penetrating inside, thus favouring the action of the aggressive agents present in the manufacturing process.
The opposite solution is to allow an exchange of air, but this can be done in a residential space or in the streets, allowing air circulation without completely encapsulating the optics. This will exploit the so called “expansion effect”, i.e. the heated LED increases the air pressure that comes out and sucks it in when it cools off. All this is not applicable in industrial spaces, where the expansion effect could suck in toxic substances.
In conclusion, spaces with a concentration of potentially toxic substances require specific LED products.”
Does this mean that products are becoming more specialised?
“Yes, exactly. Today, the attention of manufacturers is focused on LED performance. It is a necessary step for ensuring the development of this technology. We have heard about the quantitative performance of LEDs, such as energy savings and long life. Now the time has come to consider the qualitative performance and help end users understand the possible differences between the many products available on the market.
LED life, for example, can be fully exploited only with quality fixtures and the most important manufacturers who use our LEDs carry out tests on their fixtures. Today, lighting installers in industrial plants must turn to companies which have proper know-how and can suggest the best solutions, also based on the presence of aggressive and potentially dangerous agents for the LEDs.
LED lighting has reached a high degree of specialisation in several sectors. Let us mention the retailing sector, where we can create a lighting system that will enhance the white colour in stores that sell wedding gowns or that can highlight the colours of different types of food products.
In industrial areas, these quality criteria are even more important. In the places where workers spend at least eight hours a day, lights should give a correct perception of what workers are doing and ensure visual comfort. A great number of studies demonstrate how proper lighting in work places, without glare and that provides the right light level (lux), increases productivity.
This performance is difficult to quantify, it is not an immediate measurement, such as the lumen/watt ratio, but these factors are the ones that help differentiate the products on the market that declare the same performance.”
Astro: technology for energy-efficiency and safety
Lighting that protects the environment, saves energy, is good for people’s health and improves the quality of life both indoors and outdoors. Astro wins the technological challenge thanks to a perfect design in terms of shape and technical specifications, making it the perfect product for new installations and relamping projects. The exceptional energy savings that can be obtained by replacing an old lighting system with the new Astro lights ensures a quick payback with extraordinary advantages that are not only economic. The lighting quality of latest generation LEDs multiplies the benefits in any application: at work it offers greater lighting quality and improved colour rendering, increasing safety and productivity, plus it includes a technology that eliminates flicker and glare, protecting the health and wellbeing of workers. In sporting facilities, in addition to saving on management costs, it offers a perfect lighting for photo and video purposes. Astro can be used outdoors, as a suspension lamp and for central road installation, in two versions, with wide beam, symmetric and street light. The different combinations of LEDs (16, 24, 32 48 and 72) have very low consumption ranging from 2.1 to 8 W per LED.
- Posted by Redazione
- On December 10, 2016
- 0 Comments