Lighting Technology

 
 
LIGHTING TECHNOLOGY
LED TECHNOLOGY

Over the past decades the lighting industry was shaped by rapidly evolving new lighting technologies and applications. LEDs (Light emitting diodes) are semiconductor devices that convert electricity into light. They have been in operation all around us since the late 1950s, initially being used as simple indicator light in electronic appliances. Their tiny size and low power consumption rendered them a very competent indicator, perfectly suitable for visual indication on particular points such as computers, digital clocks, radios or remote controls.

The developing race among manufacturers in LED technology, however, results nowadays in a rapidly growing potential of these small electronic devices. Over the past years the traditional concept of application underwent a transformation due to continuous material and semiconductor advancement. The significant improvement of visible brightness, form factor and switching response created a multiple of new and unique application possibilities and enabled a new category of lighting: these days LEDs process data, function as light source and can even display text, whole graphics and images when collected together. Recently developed white LED can be used for general lighting. Continuous improvements in LED lighting technology promises to not to only let LEDs replace the ordinary light bulb, but also to become the most common device to be utilized in today’s society.

What is the difference?
LEDs differ completely from other light sources (e.g. filament lamps, discharge lamps and fluorescent tubes), not only in size and renderings, but especially in regard to how they operate. The light emittance is initiated through an “electroluminescence injection’, a phenomenon first observed in 1907 by H. J. Round experimenting with Silicon Carbide. This means light is emitted through the release of energy during the exchange of positive and negative charged atoms. Conventional light bulbs, for instance, produce light through the heating of filament to the point where it gives off light, fluorescent light bulbs through excited atoms emitting light through fluorescence, or discharge lamps by applying a certain pressure on the mercury inside the light bulb.

 

How does it work?
LEDs are semiconductor devices that emit incoherent narrow-spectrum light in a specific color when electrically biased forward.

As indicated by its name, a LED is a light emitting diode, a most basic sort of semiconductor device in the electronic field; able to conduct electrical current in one direction. A LED consists of a chip comprising two semi-conducting materials, which are separated into two areas: the n-doped side (anode), where negatively-charged electrons move to a positively charged area, and the p-doped side (cathode), where positively-charged electrons move to the negative area. The transfer area between the positive and negative semi-conductor is called “p-n junction”. Once power is applied, electron-rich (/-deficient) particles are balanced and light arises due to the interface recombination process.

LED-lighting is also commonly called Solid State Lighting (SSL), since a diode is a solid state device with no moving mechanical parts involved. There are several benefits coming along with Solid State lighting devices such as their low power consumption, long lifetime and resulting maintenance costs, their vibrations resistance and no UV radiation, as well as their digital controllability and instant response.

For practical use, some types of LEDs are assembled onto printed circuit boards (PCBs), which in general are additionally equipped with electronic components to control the current flowing through the LED. Depending on the assembly of the LEDs onto the PCB, different types can be defined. Next to Radial LEDs (LEDs with legs that pass through holes on a PCB, fixed underneath the PCB via soldering) which are commonly used on LED screens, Surface Mount LEDs (commonly called LED SMD) are the most common and modern nowadays. Assembled directly onto the PCB, their size can range from small to large depending on usage and intended power. Unlike radial LEDs, SMDs normally do not have cover lenses but emit a more even light output on the surface.

*SMD - Surface Mount Device

HISTORY

First developed in the 1950s, LEDs were originally only available in infra-red. These LEDs were put to good use in remote controls, televisions and a few other appliances.

Between 1950 and 1990, Red, Green and Amber LEDs were developed - the mid 1990s saw the Blue LED come to light, from which white light could be produced by mixing red, blue and green (additive color mixing). Since the introduction of the Blue LED, their general light output has doubled approximately every two years.

Up to then, white light only could be produced by the combination of “rainbow” groups of three LEDs – red, green, and blue – yielding to each other, for receiving an overall white light.

During the last years, new white LEDs have become available by combining different phosphor types with a UV LED. This new method not only permits to create new white light source, but also enlarge the spectrum of RGB colors: even colors such as purple, orange or pink are now possible to create, setting no limits to the universe of color display.

OLEDs

Another revolutionary illuminant is the organic LED (OLED). Until today OLEDs are mainly used in displays of electric household appliances and mobile phones, but based on advanced researches OLEDs have the potential to be used for another generation of innovative lighting solutions in a few years. Generally organic LEDs are based on glass substrates. Further components are a luminiferous layer, the electric contacting and the casing. Operable prototypes show that it is possible to create a flexible light source based on ductile transparent substrates.

Continuous researches of materials resulted in the development of a number of organic material systems, in which light can be generated. These systems are classified into two groups, organic LEDs with small molecule chains (sm-OLEDs) and LEDs with large molecule chains, so-called polymers (pOLEDs). The two groups can be differed by the number of materials needed to create the luminiferous layer. The organic part of sm-OLEDs consists of four layers; however, p-OLEDs can reach the same functionality with only two layers.

Depending on the organic material used, each color of the visible spectrum can be created, including white light. The advantage of OLEDs is their ability to generate white light already in the organic layer by light interference. Using this method of light interference, white and colored OLEDs can be created, completely lucent when switched off. Manufacturing these kind of lucent OLEDs is very simple, but it is not possible to change the color of their light; the light can only be dimmed. The interference to white light allows the adjustment of the color temperature, which offers the opportunity to create color gradients.

An alternative for mixing white light is by mixing blue light of the organic layer and yellow light of the conversion luminescent material.

OLEDs offer a maximum flexibility in coloring and dimming, but their costs are still high.

BENEFITS

As a result of the increasing demand for more efficient, flexible and creative lighting solutions in recent years, LED (Light Emitting Diode) lighting technologies have been evolving tremendously. Offering a convincing set of advantages including low energy consumption, high durability as well as the ability to generate a huge spectrum of different colors, LEDs present a viable alternative to conventional light sources and has become an attractive medium for numerous industries.

Economic advantages
Consuming only 10 – 20% of the power required by regular lighting sources, LEDs are very energy efficient. Whilst, for instance, a regular traffic light containing an incandescent light bulb draws 150W, the application of LEDs reduces the energy consumption to 10W. This does not only allow tremendous energy cost savings, but also a reduction of the environmental impact of artificial lighting which has become a worldwide concern in recent years.
In contrast to conventional light bulbs which generally expire after 5,000 hours, the lifetime of LEDs ranges from 35,000 to more than 50,000 hours - this is equal to more than 51/2 years of continuous operation. Consequently, replacement costs of LEDs are reduced to a minimum for the customer.

Based on its advanced construction, LEDs are very durable: while regular light sources are very fragile and sensitive to shocks and vibrations, the encasement of high strength optical grade resin of LEDs renders them extremely resistant to outside influences. This robustness significantly reduces maintenance costs and makes LEDs highly suitable for most demanding installations indoors and outdoors. Due to their energy efficiency, long lifetime, and high durability, LEDs do not only operate on an environmentally friendly basis, but also reduce costs significantly. Despite the fact that the initial cost of LED bulbs is higher than that of incandescent or halogen light bulb, the long term savings certainly pay off.

Advantages for Design and Architecture
RGB LEDs can emit a wide range of different colors (up to 16.7 million) and can be used in conjunction with one another to create color changing effects. The application of a control system enables the user to define brightness, color and speed of color changing of an RGB LED. As they start instantly and react directly to control, they are ideal for quick, dynamic light scenes. The small size of a LED allows their manufacturing in a variety of shapes which renders them a flexible lighting source for every kind of application.

The LEDs' low voltage usage, the low level of generated heat, as well as the fact that they do not produce any UV radiation render LEDs not only a convenient and flexible lighting solution, but also a highly secure one. While conventional light sources frequently cannot be used for illuminating certain materials, LEDs are combinable with almost every type of material, offering its users an unlimited range of application possibilities.

Environmental advantages
LEDs are low energy products which reduce carbon emissions. As they contain no sulfurs or phosphors like other light sources, they are an eco-friendly product for disposal, contributing actively to the protection of the environment.

FUTURE TRENDS

The rapid development of LEDs consisting of a continuously climbing light output, improvement of light efficiency and quality, increasing energy savings as well as shrinking cost, renders LED light bulbs the light source of the 21st century. Resulting in a strong market growth, LEDs are set to conquer the lighting industry.

From indication to Illumination:

Monochrome Indicators

  • Traffic lights, automotive, exit signs etc
  • Portable appliances, cell phones & PDAs
  • Signage
  • Direct view displays; video screens
  

Emerging Applications

  • Transportation: marine, auto, aviation etc.
  • Lighting niches

Areas of application:

  • Architectural
  • Entertainment
  • Hospitality
  • Shop

=SSL for small scale applications

  

Near Future

  • General Illumination
  • White LEDs replacing conventional light bulbs

Areas of application:

  • Residential
  • Consumer

=SSL for large scale applications

 
Nowadays, five major trends become apparent:
  1. Broader use of LED-fixtures: especially the semi-professional market is characterized by an increased use of LED-fixtures. A growing ecological awareness and new environmental directives render LEDs the lighting solution of the new century: their longevity, low power consumption, high light output and low maintenance costs render them perfectly suitable for any lighting installation, no matter if short-term or permanent, large scale or small scale. Especially in applications located in hard-to-reach and thus difficult to maintain areas, such as recessed and angled spaces like high buildings, bridges etc. the longevity and durability of LEDs represent the solution. A strong development resulting in increasing performance and higher light-output will enlarge the application areas and design possibilities of LEDs.
     
  2. Higher demand of interactive LED systems: Especially for the professional market, as lighting applications become more and more elaborate, the development of interactive and more efficient LED-systems are of great benefit. The usage of sensor systems (e.g. tracing motion, body heat, speed etc.) becomes more and more popular, rendering installations as flexible as never before. For instance, a regular public lighting system based on interactive LED lighting benefits not only of the increased energy saving potential and low maintenance costs of the LEDs, but also of even further cost savings due to the system’s capabilities such as creating “light on demand”: the sensor system, interacting with the public, can increase or decrease the amount of lights exactly to the amount of people, their movements or speed. Next to the cost reduction and energy efficiency, an added artistic value is also added to the lighting installation - creating a unique experience for the observer.
     
  3. Penetration of the consumer market: LED lighting becomes more and more the focus of consumers and will enter everyday life in the near future. Low intensity LEDs can already be found in many sectors such as electronic equipment, toys, domestic appliances, traffic signal etc. In the future LEDs will play an increasing role for end-users, as the new technology of high power LEDs is on the advance. Due to increasing benefits such as energy efficiency, longevity, low maintaining costs as well as continuously decreasing acquisition costs, LEDs are attractive as never before for the residential market. LEDs are already used for decorative lighting and will in the near future replace some conventional light sources in everyday life.
     
  4. Increasing use of White LEDs: The price/performance situation of white LEDs continues to improve and makes white LEDs more and more competitive to conventional white lighting sources. Compared to conventional light bulbs (e.g. incandescent lamp, discharge lamp), their extremely high light output and brightness, as well as their unique flexibility to adjust the color temperature of the white light output (ranging between 3000 and 7000K) render white LEDs the light bulb of tomorrow. White LED applications, for instance, will soon become one of the standard light sources for functional illumination, revitalizing central cities and encouraging high-density housing.
     
  5. OLEDs on Advance: OLEDs are solid state devices made with organic material (OLED), handled as the next generation of LEDs. The latest organic light emitting diodes are more powerful, use less power, and are more efficient than conventional diodes and represent an alternative and still more ecological solution. Their unique variability in application due to their tiny size, extremely low heat emission and flexibility render them a perfect solution for advanced lighting applications - even on elastic surfaces like fabrics if produced with a high density.
Glossary
AC(Alternating Current)
Bi-directional electric charge.
Art-Net™
A proprietary protocol developed by Artistic License.
Audio DSP (Digital Sound Processing)
Representation of audio signals to digital signals for processing. Sound to Light.
CCT (Correlated Color Temperature)
The value, in degrees Kelvin, which most closely matches that of a point on the Planckian locus or black body radiator curve, emitted by an ideal black body radiator. The CCT occurs above or below the Planckian locus, the distance from which is represented by ΔUV. CCT is produced by sources which generate light via emission methods other than incandescence, such as passing an electric arc through a gaseous discharge (fluorescent, HID), or using semiconductors, (LED).
Color Temperature
A point on the Planckian locus, measured in degrees Kelvin, which represents the heating of an ideal black body radiator to the point of incandescence. Only filament based sources which use incandescence as their light emission method have a color temperature. White light that is perceived as cool generally falls on the Planckian locus between 5000 K and 6500 K, white light that appears neutral falls generally between 3500 K and 5000 K, and white light perceived as warm generally falls between 2700 K and 3500 K.
Contrast Ratio
The ratio of the luminance of the brightest color (white) to that of the darkest color (black) that the system is capable of producing.
Cue
One static lighting scene saved in the e:cue Lighting Application Suite software. This concept is based on professional lighting control consoles.
Cuelist
A set of consecutive cues forming one dynamic lighting sequence.
DALI (Digital Addressable Lighting Interface)
A digital protocol used in lighting control, typically for electrical ballasts and dimmers, and commonly used to control fluorescent lighting.
DC (Direct Current)
Electric charge that flows in one constant direction.
Daisy-chain
A topology in which multiple devices are connected, one after another, in sequence.
Digital dry contact inputs
Digital input used to integrate external devices, such as occupancy and motion sensors, various buttons, regular light switches, and other building control devices. Also known as “dry contact closures”, or simply “dry contacts”.
DMX512 (Digital Multiplex)
A standard communication protocol originally used in stage lighting, and increasing in use in architectural lighting, for communication between controllers and lighting fixtures.
DMX512 Universe
A data link transmitting 512 DMX512 channels.
DSI (Digital Signal Interface)
A protocol used for lighting control in buildings.
Dynamic White
A mixture of warm white and cold white LED nodes, which allows the user to tune various CCTs from warm to cold.
e:bus
A special e:cue protocol used to communicate between the Glass Touch Series and the Butler XT2, for system integration. The e:bus protocol functions using only two wires for power and data using any network topology.
e:net
An Ethernet-based e:cue protocol used as the backbone communication standard between most e:cue Engines and Interfaces.
e:pix
An e:cue protocol similar to DMX512, for faster communication between the VMC and Traxon Technologies e:pix-capable LED media products. Can handle more control channels as DMX512.
EIB (European Installation Bus)/KNX
EIB, presently succeeded by KNX, is a standard communication protocol for building automation.
Efficacy
The ratio of the luminous flux of a light source to the power required to produce that flux. Efficacy is expressed in lumens per Watt (lm/W).
IP Rating (Ingress Protection Rating)
A classification of the degree of protection provided against the intrusion of solid objects such as dust, accidental contact, and water into electrical enclosures. The rating consists of the letters “IP” followed by two digits and an optional letter.
KiNET™
A proprietary protocol developed by Color Kinetics.
Luminous Flux
The measure of the perceived power of light, if reflects the varying sensitivity of the human eye to varying wavelengths of light.
MIDI (Musical Instrument Digital Interface)
A standard protocol that enables electronic musical instruments, computers and other electronic equipment to communicate and synchronize with each other.
Pitch
The distance between the center of two adjacent pixels in an array.
PoE (Power over Ethernet)
Power over Ethernet (PoE) technology describes a system to safely pass limited electrical power, along with data, on Ethernet cabling (cat5 or higher). Power can come from a power supply within a PoE-enabled networking device such as an Ethernet switch or from a device built for “injecting” power onto the Ethernet cabling.
PWM (Pulse Width Modulation)
A dimming technique made possible through constant voltage and turning the LEDs on and off at varying high frequencies, at which the human eye cannot detect any flickering.
RDM (Remote Device Management)
A protocol based on DMX512-A with bidirectional communication capability between a lighting controller and RDMcapable lighting fixtures or devices.
Resolution
The measurement of the total number of pixels within the display area.
RS232
A standard for communication between devices in a control system, which allows interfacing with various competitorcontrolled devices, as well as residential and building automation systems.
Smart Chip
An auto-addressing system available in Traxon Modules, Boards, Coves, and Strips.
SUITABLE FOR COASTAL ENVIRONMENT
Coastal locations present particular challenges for specifiers, designers or owners when choosing suitable lighting solutions due to the amount of airborne salt and humidity that a coastal property is subjected to, as these act as catalysts to oxidation and rust.
Traxon Nano Liner Allegro AC XB, Monochrome Tube, Media Tube, and Wall Washer Shield AC XB are proven suitable for coastal environments. These weather-proof lighting solutions underwent vigorous assessments including 200 hours salt spray tests and 168 hours high temperature/high humidity tests to verify their resilience to corrosive sea air. These luminaires are suitable for use in coastal environments and have 3 or 5 years functional warranty.
TX CONNECT®
A simple connection system, that combines power and data into a single cable in many Traxon fixtures.