LUMISSION 2021 catalog update june 2021

C
Quality of Light
NE: Kwaliteit van het licht
188
A LED is a Light Emitting Diode and thus an electronic semiconductor
component. This so called diode actually works as a kind
of valve because it only lets current through in 1 direction when
a certain voltage is applied. This voltage depends on the material
used inside the diode and varies from 1.2V to 3.5V.
A LED contains 2 different semiconductors. Due to the interaction
of the different electrons in these 2 semiconductors (also called
stamp), which occurs with the above voltage drop, energy is
emitted in the form of photons (light particles).
This is called the injection electroluminescent process the emitting
of actual light. Unfortunately some of these photons are also
reabsorbed by the stamp, which result in heat development.
At least 50% of the energy is converted into light making LED technology
more efficient than any other type of light source.
The colour of the light emitted by LEDs depends on the mixed
materials used in the stamp and is monochromatic in colour where
white is not possible at first. The colour white is only obtained
later by adding an extra yellow phosphor in the epoxy layer with
specific blue LEDs.
White shades: white is a mixture of all colours from the visible
part of the colour spectrum. We can distinguish different shades
(experiences) with white LEDs. These shades of white are expressed
in correlated colour temperature (CCT) with the unit Kelvin.
It is possible to simulate any desired colour temperature, however
in practise the temperatures listed below are formulated in the
functional lighting industry.
Extra warm = 1800K~2700K
Warm white = 3000K
Neutral white = 4000K
Cool white = 5000K~6500K
See picture B
B
3000K CRI 100 3000K CRI 90 3000K CRI 80 3000K CRI 70
The quality of light of a luminaire depends on many different
parameters. The colour rendering index CRI is a measure of how
real colours are rendered in the light from artificial light sources.
This value can vary between 0 and 100.
The closer to 100 the better saturated colours are perceived.
For most functional lighting applications CRI80 is sufficient.
See picture C
Binning is the sorting of LEDs in the manufacturing process and is
necessary for applications where light quality and reliability are
paramount. For LUMISSION luminaires it is important that the
LEDs have an identical visual light output and light intensity and
therefore always use only specific same binnings for production.
Next to binning of leds optical systems like the reflector and
diffusor design are very important to eliminate unwanted visual
effects and make sure the luminaires have a nice homogenous and
non blinding lighting effects. Also the optical system has an effect
D
on the quality of light and will influence the colour tolerance
number of the luminaire. This colour deviation number is expressed
in the unit MacAdams steps and can be divided into 7 steps of
SDCM. The LUMISSION luminaires for functional lighting all have a
SDCM