Beam angle

The design of the LED requires the use of optics that bundle the emerging light and thus enable a defined beam angle.

Accent light

Accent lighting is used to emphasise structures and outlines. Accent lights highlight subtleties of objects and can create reflections and highlights. Accent lighting must be applied separately to rooms and objects for a meaningful effect.


The illuminance E is a measure of the light hitting a surface. This is also referred to as luminous flux density. The unit of illuminance is lux [lx].


Glare affects the visibility of details and well-being. Normally, glare is divided into: unpleasant glare and vision-limiting glare.


The production of state-of-the-art high-power light-emitting diodes is a complex process in which certain manufacturing tolerances cannot be avoided. For this reason, it is necessary to sort the semiconductor elements after production according to their colour values and efficiencies. This process is also called binning. This ensures that the LEDs in a production series have similar operating characteristics (such as colour and efficiency). The tighter the manufacturing tolerances are set, the better the quality of individual bins, i.e. the similarity of the individual LEDs. This is particularly important when, for example, a large number of identical LEDs are used in a spotlight.


Luminous intensity (I) is a basic unit of the International System of Units and is measured in candela (cd). Luminous intensity indicates the luminous flux density (intensity) of a light source in a certain direction, whereby the luminous intensity is unevenly distributed in different directions. This directional dependence is indicated in luminous intensity distribution curves (LVK), in which the luminous intensity for different beam angles are shown.

CE mark

The CE mark is not a test mark but an administrative mark, the affixing of which is required by new EU directives. The CE mark is a condition for the sale of electrical products within the European Union. It serves as a confirmation for manufacturers and importers that their products meet the requirements of specific EU directives.


To change the brightness of an electrical consumer such as a light bulb, dimmers are used to reduce the electrical energy.


The standard protocol for transmitting control signals in lighting technology is the DMX512 protocol. This allows 512 channels per data line to be controlled, whereby each channel can assume an 8-bit value between 0 and 255 (0% - 100%).

Colour rendering index Ra/CRI

The Colour Rendering Index (CRI) is the colour rendering index used to characterise light sources. It is an index for the naturalness of colours. The greater the colour rendering index, known as the CRI or Ra value, the more natural colours are rendered and the more pleasant they are perceived. The size of the CRI value can be between 0 and 100 and is decisive for the colour rendering of illuminated objects. In other words, only the light colours that are also contained in the light source can also be reflected on the illuminated body. If, for example, red is missing, a red towel looks grey.

Colour temperature

The colour temperature is a measure of the colour impression of a light source based on the black body, the unit is Kelvin (K).

Intensity (LED)

The intensity of the radiation produced by a light emitting diode increases proportionally with the current, with the current limit currently being 20mA. When this limit is exceeded, excess heat is generated, resulting in a reduction in light intensity and the life of the light emitting diode.


Refers to a process in which by mixing different shades of white - usually cool and warm white - white tones are produced that are matched to the place, time and task. This means that different colour temperatures can be reproduced. Sometimes a little red is added for application-specific purposes. This form of colour mixing is also called "kelvin shifting" and is mainly used to simulate the light colour of lighting according to the natural course of the day.

Service Life

The service life of a light emitting diode is well over 100,000 hours at an average temperature of 25°C (corresponds to 11.5 years of uninterrupted operation).


Luminance is a measure of the impression of brightness that the eye has of a self-luminous or illuminated surface. The unit of luminance is cd/m². From luminance levels of about 0.75 cd/m², the eye is dazzled.

Luminous efficacy

The lumen/watt ratio is also referred to as luminous efficacy n. The luminous efficacy indicates the luminous flux generated in relation to the electrical power expended.
Luminous efficacy of various light sources:
Incandescent lamp 60W = 12 lm/W
Fluorescent lamp 58 W = 78 lm/W
Sodium vapour lamp 105 lm/W

Light distribution curve

The luminous flux of a light source does not radiate evenly on all sides. The luminous intensity distribution depends very much on the type and design of the light source. The installation of the light source in a housing, a luminaire or in an optical system also changes the luminous intensity distribution of the light source. A luminous intensity distribution is drawn in a polar diagram, with the light source in the centre of the diagram and the luminous intensity decreasing towards the edge of the diagram. The diagram indicates the luminous intensity as a function of a beam angle with the unit lumen.

MacAdam ellipse

A MacAdam ellipse, after David L.(ewis) MacAdam, is that circumference in the CIExy diagram around a reference hue in which the comparison colours are perceived to be equidistant.

RAL colours

The RAL system comprises around 200 colours, divided into high-gloss and matt and distinguished by a four-digit number.

Protection classes

The protection classes describe the type of protection against dangerous body currents for electrical equipment.