LED Modules
An LED module consists of the individual LEDs soldered onto a printed circuit board or PCB. ERCO sources the LEDs globally from reputable manufacturers, specifying the luminous flux, luminous efficacy, colour rendition, colour temperature (i.e. colour of light) and consistency in mass production. The choice of suitable LEDs and their arrangement on the PCB depends on the actual lighting task. In-house PCB design allows optimisation of the complete system. This involves using suitable layouts for each separate light intensity distribution and precise mounting points for the secondary lens, while also considering optimum heat dissipation from the LED chips via the PCB to the housing.
PCB for optical projection system
The yellow surface coating of the LEDs emitting white light is a fluorescent material for luminescence conversion. Optimised spacing between the LEDs assists the heat management on the PCB. The round openings facilitate the precise and safe mounting of the collimating lens as part of the optical projection system.
PCB for optical reflection
Optical systems that direct the light via a light mixer improve efficiency if the PCB has a high reflectance. For this reason PCBs are painted white and the arrangement of LEDs on the PCB is designed to suit the optical system.
PCB for grazing light
Grazing light requires a linear light source. The PCBs for facade washlighting are therefore arranged in a line.
Neutral white and warm white
Binnings
ERCO offers LED luminaires in neutral white or warm white . This allows lighting designers to select the colour of light to suit the material colours and spatial atmosphere or to create cold-warm contrasts.
The LED manufacturing process results in certain variations in the colour loci of LEDs. LEDs are accordingly sorted into so-called "binnings". Uniform lighting quality requires the strict selection of components from defined binnings.
Warm white LEDs
The relative spectral distribution of the warm white LED with luminescence conversion is closely related to the relative brightness sensitivity of the cone cells of the human eye. The result is high luminous efficacy and good colour rendition.
RGB LEDs
The RGB LEDs are ideal for mixing highly saturated coloured light. However, the white light from RGB LEDs does not give satisfactory colour rendition quality, making it less suitable for lighting tasks where colour is critical.
RGBW LEDs
Mixing RGB LEDs with warm white LEDs combines the advantages of both systems: RGBW luminaires produce variable shades of white along the Planckian curve with excellent colour rendering, but also coloured light in pastel hues all the way to the highly saturated range.
LEDs (Light Emitting Diodes) are semiconductor elements that directly convert electrical energy into light via electro-luminescence. The outstanding characteristics of LEDs include robustness, long functional life and a high luminous efficacy with high potential for further increase. White LED-light is free of ultraviolet and infrared components and therefore has advantages from a conservation point of view. Daylight white LEDs offer higher efficiency, whereas warm white LEDs have better colour rendition quality. LEDs are dimmable and offer high switching stability, making them ideally suited for lighting control and additive colour mixing. Unlike other light sources, RGB LEDs do not produce any transmission losses through colour filters. To exploit the luminous flux of the temperature sensitive LEDs to the full, good thermal management is indispensable.
Spectral distribution
Coloured light
The radiation spectrum of warm white LEDs is free of ultraviolet and infrared components and has a reduced blue component. Its relative damage factor for sensitive exhibits is less than for halogen lamps with UV filters, making warm white LEDs recommendable for museum lighting.
The saturated LED lighting colours enable a wide variety of mixed colours within the triangle of red, green and blue . LED modules with additional white LEDs, known as RGBW modules , improve the colour rendition for the colours of light with respect to the Planckian locus.
LED manufacture
Manufacture
Modern production plants for compound semiconductor materials are geared to short throughput times and high production quantities. Hundreds of LED chips are produced from one wafer. (Photo: AIXTRON).
Construction of an LED
The small, light-producing LED chip is fitted onto a large heat sink for good thermal management. The lens takes care of the primary light guidance.
Like microchips, LEDs consist of semiconductor crystals and are produced using similar methods. The production plants build up the semiconductor layer-by-layer on a wafer. The upper and lower layer of the LED chip features an anode or cathode and the light is produced from the zone in the centre. Despite the use of cutting-edge production plants, not all areas of the wafer have the same properties of luminous flux and colour location. The result is that "binning", i.e. the selection category after cutting the wafer into individual LED chips, becomes essential. ERCO only uses LEDs of the highest grade and with identical characteristics in its luminaires.
