LED Technology Glossary

Light Emitting Diode (LED)
A Light Emitting Diode (LED) is a solid-state semiconductor device that converts electrical energy directly into light.

Luminous Flux
Unit of measurement: lumen (lm).
All the visible radiated power emitted by a light source and perceived by the eye is call luminous flux.

Luminous Intensity
Unit of measurement: candela [cd]
Generally speaking, a light source emits its luminous flux in different directions and at different intensities. The visible radiant intensity in a particular direction is called luminous intensity.

Luminous efficacy
Unit of measurement: lumens per watt [lm/w]
Luminous efficacy is the ratio of luminous flux to power. The power can be either the radiant flux of the source’s output, or it can be the total electric power consumed by the source.

Unit of measurement: lux (lx)
Illuminance is the ratio between the luminous flux and the illuminated area. An illuminance of 1 lx occurs when a luminous flux of 1lm is evenly distributed over an area of 1m².

Unit of measurement: candelas per square metre [cd/ m²]
The luminance of a light source or an illuminated area is measured of its luminous intensity per unit area of illuminated surface.

Colour Temperature
Unit of measurement: Kelvin [K]
Cool White: 5000 ~ 6000k
Natural White / Day Light: 4000k
Warm White: 3000 ~ 3500K

The colour rendering index (CRI), sometimes called colour rendition index, is a quantitative measure of the ability of a light source to reproduce the colours of various objects faithfully in comparison with an ideal or natural light source.

RGB Colour
An additive colour model in which red, green, and blue light are added together in different proportions to produce a broad range of colours, including white.

IP Rating Index

First number
(Protection against solid objects)
Definition Second number
(Protection against liquids)
0 No protection 0 No protection
1 Protected against solid objects over 50mm(e.g. accidental touch by hands 1 Protected against vertically falling drops of water
2 Protected against solid objects over 12mm(e.g. fingers) 2 Protected against direct sprays up to 15° from the vertical
3 Protected against solid objects over 2.5mm (e.g. tools and wires) 3 Protected against direct sprays up to 60° from the vertical
4 Protected against solid objects over 1mm (e.g. tools, wires and small wires) 4 Protected against sprays from all directions – limited ingress permitted
5 Protected against dust – limited ingress (no harmful deposit) 5 Protected against low pressure jets of water from all directions – limited ingress permitted
6 Totally protected against dust 6 Protected against strong jets of water e.g. for use on shipdecks – limited ingress permitted
7 Protected against the effects of temporary immersion between 15cm and 1m. Duration of test 30 minutes
8 Protected against long periods of immersion under pressure