GLOBAL MARINE & OFFSHORE LIGHTING SOLUTIONS Ten things you should know about LED

LED: Light source of the future LED is without doubt the most talked-about issue in the lighting industry these days. What makes LED so interesting? Light Emitting Diode. An assembly of one or more LEDs on a printed circuit board. LE D D R I V E R : The power control used to manage the light output of the LED module. TOTA L LUM I N O US FLUX: The amount of light coming from a light source or luminaire. TOTAL POWER CONSUMPTION: The power con-sumption of the whole luminaire or system, including losses. Lumen per watt. Lumen out of the light source or luminaire, divided by the total power consumption....

1 LED is a small and powerful light source that is changing the world of lighting. A Light Emitting Diode (LED) is an electronic component that generates light in a semi-conductor material. Using the right materials, a diode may produce visible light of various wavelengths. White light is created by either using a blue diode or “chip” and adding yellow phosphor on top of it or mixing light from one red, green and blue diode (RGB). The use of phosphor conversion is the most used method in the lighting industry, due to its high efficacy and flexible production method. The phosphor can be added...

LEDs are more efficient than many conventional light sources. Conventional luminaire “Light output”: Watt Efciency: Light Output Ratio Ballast Optics FL tube LED luminaire Light output: Lumen Efcacy: Lumen per watt One of the advantages of LED is that all the light is emitted in one direction. This entails fewer reflections inside the luminaire since we normally want the light to go downwards only. If we need a light distribution that goes both up and down, the LED is less suitable compared to e.g. a fluorescent lamp. The performance of a LED is often measured in terms of lumen per watt or luminous...

The typical lumen maintenance curve of LEDs according to most manufacturers. After 50.000 hours, the remaining light output is 70% of the original output. Lifetime data can be given in terms of B50 (normal case), where 50% of the diodes are better than the given lifetime value, or B10 (worst case), where 90% of the diodes are better than the given value. LEDs last longer and do not need to be replaced as often as many conventional light sources. One of the benefits of 20k 30k 40k its50k 60k lifetime. the LED is long 70k 10k Because it has no movable parts or filaments that may break, LED’s can...

LED lifetime is determined by the temperature inside the diode. Inside the LED the temperature may get very high. This causes the LED to gradually emit less and less light. The higher the internal temperature, the faster the lumen degradation. At high internal temperatures, the blue chip and phosphor layer degenerates and the LED will eventually lose light. This happens gradually and the LED will slowly fade away. The internal temperature depends on the ambient temperature. The higher temperature of the LED’s surroundings, the higher internal temperature. A stor y often heard is when increasing...

With a lumen maintenance factor of 0,7 lighting installations risk over dimensioning. Since the definition of LED lifetime is related to L70, the lamp lumen maintenance factor (LLMF) is therefore 0,7 This light loss is countered . by adding extra light in the lighting installation’s initial phase. The other factors that contribute to the light installation’s maintenance factor (MF) are the light survival factor (LSF), the room surface maintenance factor (RSMF) and the luminaire maintenance factor (LMF). The product of these factors will bring the maintenance factor (MF) down to somewhere between...

LEDs come in all colour temperatures, but white LEDs are not always white. Because LEDs do not have a full colour spectrum, we must pay special attention to their colour quality and colour rendering capabilities. Otherwise, a lighting installation with visible colour differences may be the outcome. When LEDs are produced, the production outcome is LEDs with many different colours or colour temperatures. CIE’s 1931 colour diagram is use d to cre ate a binning structure, i.e. groups of diodes that share the same colour characteristics. The LED suppliers offer different bins to luminaire manufacturers....

The colour rendering capability of a LED is influenced by its colour spectrum. As LEDs do not have a full colour spectrum, proper colour rendering from LED luminaires may be a challenge. However, LEDs are available with very high colour rendering capabilities. Light sources render colours differently depending on the colour of the light already present in the light emitted from the source. For example, if the light emitted does not contain any red light or wavelengths, red colours will look grey under this light. We measure this effect by the colour rendering index, CRI or Ra. Ra is the average...

Because LEDs are perceived as brighter than conventional light sources, you may design installations with lower lux levels. “What we see we cannot measure – and what we can measure we cannot see”. In both indoor and outdoor lighting, the perceived lux levels from LED luminaires may differ from the actual light measurements. For example, a light calculation for LED flood lights, based on conventional lux requirements, may result in too higher perceived light levels at low background luminance levels. Why does this occur? The standard way of calculating and measuring lux levels is based on light...

Retina Blue-sensitive cone Green-sensitive cone The human eye consists of different types of photo receptors. Cones are colour sensitive to blue, red and green colours. Rods are sensitive to low light levels. Receptors for visual system Test with 400 W High Pressure Sodium lamps in flood lights. Average illuminance level: 286 lux. Test with 160 W LED luminaires. Average illuminance level: 95 lux. The installation seems equally bright or brighter to the human eye. Both pictures were taken with identical parameters: Exposure time 1/2 sec; F-Number: 8; ISO speed: 400.