Emerging Applications of LED Lighting Systems

LED (Light Emitting Diodes) are the latest and most exciting technological advancement in the lighting industry. LEDs are small, solid light bulbs which are extremely energy efficient and long lasting. LEDs operate differently than traditional incandescent light bulbs. LED’s are different to standard lighting. They don’t really burn out and stop working like a standard light, moreover the lighting diodes emit lower output levels over a very long period of time and become less bright. A number of benefits associated with LED lights can be summarized as:

Long Life – LED bulbs and diodes have an outstanding operational life time expectation of sometimes up to 100000 hours.

Energy Efficiency – LED are today’s most efficient way of illumination and lighting, with an estimated energy efficiency of 80%-90% when compared to traditional lighting and conventional light bulbs.

Ecologically Friendly – Most conventional fluorescent lighting bulbs contain a multitude of materials like e.g mercury that are dangerous for the environment.  LED lights contain no toxic materials and are 100% recyclable, and will help to reduce carbon footprint by up to a third. The long operational life time span of LED light bulb can save material and production.

Durable Quality – LEDs are extremely durable and built with sturdy components that are highly rugged and can withstand even the roughest conditions. Because LED lights are resistant to shock, vibrations and external impacts, they make great outdoor lighting systems for rough conditions and exposure to weather, wind, rain or even external vandalism, traffic related public exposure and construction or manufacturing sites.

Zero UV Emissions – LED illumination produces little infrared light and close to no UV emissions. Because of this, LED lighting is highly suitable not only for goods and materials that are sensitive to heat due to the benefit of little radiated heat emission, but also for illumination of UV sensitive objects or materials such a in museums, art galleries, archeological sites etc.

Design Flexibility – LEDs can be combined in any shape to produce highly efficient illumination. Individual LEDs can be dimmed, resulting in a dynamic control of light, color and distribution. Well-designed LED illumination systems can achieve fantastic lighting effects, not only for the eye but also for the mood and the mind. LED mood illumination is already being used in airplanes, classrooms and many more locations and we can expect to see a lot more LED mood illumination in our daily lives within the next few years.

Operational in Extremely Cold or Hot Temperatures – LED are ideal for operation under cold and low outdoor temperature settings.  LED illumination operates well also in cold settings, such as for outdoor winter settings, freezer rooms etc.

Light Dispersement – LED is designed to focus its light and can be directed to a specific location without the use of an external reflector, achieving a higher application efficiency than conventional lighting. Well-designed LED illumination systems are able to deliver light more efficiently to the desired location.

Instant Lighting & Frequent Switching – LEDs can be turned on/off many times. LED lights brighten up immediately when powered on, which has great advantages for infrastructure projects such as e.g traffic and signal lights. Also, LED lights can switched off and on frequently and without affecting the LED’s lifetime or light emission.

Low-Voltage – LED lighting can run on low-voltage power supply. This makes it easy to use LED lighting also in outdoor settings, by connecting an external solar-energy source and is a big advantage when it comes to using LED technology in remote or rural areas.

Challenges towards LEDs:

Cost: LEDs are currently more expensive, price per lumen, on an initial capital cost basis, than more conventional lighting technologies. However, when considering the total cost of ownership (including energy and maintenance costs), LEDs far surpass incandescent or halogen sources and begin to threaten compact fluorescent lamps.

Performance hurdles: LED performance largely depends on correctly engineering the fixture to manage the heat generated by the LED, which causes deterioration of the LED chip itself. Over-driving the LED or not engineering the product to manage heat in high ambient temperatures may result in overheating of the LED package, eventually leading to device failure. Adequate heat-sinking is required to maintain long life. The most common design of a heat sink is a metal device with many fins, which conducts the heat away from the LED.

Required input: LEDs must be supplied with the correct voltage and current at a constant flow. This requires some electronics expertise to design the electronic drivers.

Colour characteristics: LED’s can shift color due to age and temperature.  Also two different white LED will have two different color characteristics, which affect how the light is perceived.

Growing applications:

LEDs have been commercially available since the 1960’s, but in recent years there have been remarkable improvements in their performance. These technology developments have enabled the use of LEDs in a variety of colored and white lighting applications. Colored LEDs have already become the technology of choice for traffic signals, much of interior and exterior vehicle lighting, signage of various types often as a replacement for neon, and other areas. LEDs are expected to become the dominant technology for most colored lighting applications. LEDs are beginning to penetrate white lighting markets such as flashlights and localized task lighting. LEDs were first used for signal lighting, such as in a dashboard and later in tail lamps. In the past few years several companies have developed high power LEDs which are extremely bright and can now be used in applications that require a high light output, such as street lighting and task lighting referred to as “lighting class LEDs.”

LEDs can be used as point sources, or can be used with light guides of various types to provide distributed illumination. LED lighting has established brand new experience through special lighting, cosmopolitan night scenes, indoor decoration lighting and display engineering. Regarding color presentation, lighting control, environmental protection, and energy-saving, it has clear advantages over traditional neon lights, incandescent lights, tungsten-halogen lights, and fluorescent lights. With further improvement LEDs have the potential to become an important technology for large area general illumination. White LED products already have performance of over 30 lumens/watt which is nearly 3x better than incandescents. White LEDs with outputs of more than 100 lumens are already available commercially, and higher power devices can be expected in the near future. However, LED needs to cut the price and finds breakthroughs in high-end digital intelligent products to penetrate the general market and enhance application levels. In this process, LED lighting will gradually replace traditional lighting in high-end application areas. LEDs are fast becoming the light source of choice for so many general lighting applications. LED-based products are poised to replace legacy light sources in virtually all general lighting applications indoors and out while also finding substantial use in many other places ranging from automotive headlamps to life-science applications such as horticulture and maintain a strong presence in backlight and display.

Some of the applications of LED lighting systems are:

Smart Lighting System

With the improvement of material and spiritual life, people nowadays have more demands to lighting. It is no longer just about lighting. Besides energy-saving, more and more people are using lights to create a harmonious, homey and comfortable environment. Smart lighting is developed based on this concept. Different lighting can create different atmosphere. Romantic, relaxed, sparkling, enjoyable, and comfortable feelings can all be created by lights. If it is possible to control indoor lighting through digital systems, residents would have more lighting variations at their will. The combination of lighting design and intelligent technology can fulfill many people’s dreams. Digital intelligent lighting is an important component of smart living. Experts predict that in the near future, smart lighting will replace ordinary lighting and become the industry mainstream.  In order to present different effects, smart lighting with traditional lights will need lots of lights, which increases costs. Moreover, it is difficult to integrate harmoniously with construction materials and interior design.  Smart lighting system is turned on and off constantly, which will increase the impact to lights and reduce their life time.  Current smart lighting systems only have regional lighting and timer functions. Color , setting and brightness control are not yet realized, so it is still far from our expectation.  Traditional lights, including incandescent lights, fluorescent lights and energy-saving lights, cannot be applied to digital control due to technical deficiencies. LED lighting can maintain lumen efficiency and light color parameter in a larger sink current range, so it can materialize digital control. Because LED is mixing RED, GREEN, and BLUE color through electronic control systems, or changing different colors in a rhythm to create a colorful and dynamic atmosphere. This effect is impossible with traditional lighting. When chips are built in lighting, which reduce the thickness and weight of lights, and it successfully integrate lighting and construction materials. When lights are off, people even forget the existence of them, but they are also omnipresent.  Compared with traditional lights, new LED lights pack chips directly into circuit boards with cooler, which reduce size and cost and increase steadiness.

Emerging applications of UV LEDs

While technology barriers remain in manufacturing UV LEDs, especially at shorter wavelengths, a number of potential high-volume applications are driving interest among packaged LED manufacturers. While visible-spectrum LEDs have penetrated into TV and mobile backlighting, automotive, general lighting, signage, and other markets, ultraviolet (UV) LEDs are just beginning to replace incumbent UV sources in diverse applications, including curing, counterfeit detection, medical, sensing, printing, and water/air disinfection. The cost of UV LEDs has dropped significantly during the past several years through improvements in architectures and manufacturing technologies. However, when compared to the price of white LEDs, UV prices are still much higher and fewer manufacturers supply UV LEDs – although volumes are high for these suppliers. As a result, more and more white-light LED manufacturers are attempting to enter this field. The highest penetration and usage of UV LEDs today is in curing applications, but other applications such as water and air disinfection are increasing their reliance on UV LEDs as the technology evolves. This growth is expected to continue in the next five years and new potential applications will emerge.

Other applications

• The use of LED technology in supplemental lighting and the impact on chemical plant growth  regulators
• The photoperiodic response of plants to LEDs
• The use of LEDs as sole-source lighting in plug propagation
• Growing hops in a greenhouse under LEDs

The Future of LEDs

LEDs continue to get brighter, more efficient and cheaper. Some predict a 2 or 3 times improvement in efficiency and brightness before the decade is over with significant price decreases. Whether these predictions are true or not remains to be seen, but what is certain is that this technology is getting popular among masses with its basic advantages and possible use in emerging & exotic applications ensuring a bright future for LED technology. Currently, almost every aspect of LED technology from substrates to systems applications is undergoing rapid technical evolution, so projections about future system level applications are highly speculative, and this assessment presumes that solutions to long standing LED issues like droop and poor green/yellow performance will ultimately be found. Future system level applications will also be tightly convolved with the system level incorporation of new types of light sensors and embedded processing capabilities so that feedback loops between the light source, the environment and the control system can be closed. Future systems level applications will also be tightly convolved the development of new features and services needed to extend business revenue models of lighting companies as the progress in LED system reliability drives future applications in lighting to the point that bulb/socket commodity business models begin to fail, and business models based on the offering of new lighting features and services are developed. Possible future LED lighting systems applications will emerge with changing trends in lighting related human health, communications, and display technologies.

Author

Dr. S. S. Verma, Department of Physics, S.L.I.E.T., Longowal, Distt.-Sangrur (Punjab)-148106