Questions & Answers

Theoretically, the only limitations are in the transport of the luminaires. Luminaires up to 2.70 m in length can be manufactured without freight forwarding. Anything longer is delivered by freight carrier. Our standard lengths for luminaire inserts range from 108 mm to 2008 mm, depending on the LED series and application. Furthermore, all our extruded profiles are supplied in 6100 mm lengths; theoretically, luminaire inserts up to 6 m in length are possible.

The reason for this is the optical material property known as the refractive index. This dimensionless physical quantity indicates by what factor the wavelength and phase velocity of light are reduced in a vacuum. The refractive index of air is generally known as 1, while the refractive index of polyurethane is approximately 1.41. When the light from an LED passes from an optically less dense medium into an optically denser medium, each color of the white light is refracted differently due to the different refractive indices. The refraction of violet light rays is strongest, while that of red light rays is weakest. This dispersion effect is responsible for the separation of white light into its spectral color components, which we observe as color shift or Kelvin drift after LEDs are encapsulated.

DALI stands for Digital Addressable Lighting Interface. DALI is a protocol for digital communication between components of a lighting system. In installations, a DALI controller organizes and manages the flow of information and access to the data line for all components.

Since lighting management doesn't require the control of fast processes, slower data transmission, as with DALI, is perfectly adequate and also contributes to reducing the cost of DALI components. Despite these deliberate limitations, DALI offers considerable functionality that goes far beyond simply switching and dimming individual DALI components. For example, constant light control loops can be created using brightness sensors, and attractive lighting scenes can be compiled, saved, and recalled.

Of particular interest in this context is the status feedback from peripheral DALI components to the central DALI controller. This enables targeted fault diagnosis and the definition of sensible maintenance intervals for ballasts and lighting technology. A two-wire cable, as used in previous lighting installations, is primarily employed as the data transmission medium. This can be implemented as a separate cable or by utilizing spare conductors within an existing power line. To ensure interchangeability between DALI components from different manufacturers, the DALI protocol is standardized internationally according to IEC 929.

Casambi is an intelligent lighting control system that uses Bluetooth to control LEDs, halogen lamps, or even traditional light bulbs. The major advantage of Casambi is that entire lighting scenes can be programmed and automatically switched on and off using a timer.

A linear regulator is a voltage regulator; it stabilizes an electrical voltage as the operating voltage of a circuit in order to compensate for fluctuations in the input voltage.

Basically, an LED assembly consists of the following parts:

• Semiconductors, as a source of radiation and heat
• Optics, for determining the radiation characteristics
• Various connection technologies as electrically and thermally conductive components of the chip
• Submount/circuit board for heat dissipation
• Housing as a protective function

LED failures can be categorized into several main groups. First, there are total failures, which can be either complete or temporary interruptions caused by the chip itself or by disturbances in the electrical path. These interruptions can be caused by mechanical overload, chemical, or thermal processes. Another type of total failure is an electrical short circuit. Here, electrical overload and silver growth play a role.

Degradation failures involve changes in optical, electrical, or thermal properties, or a combination thereof, with the "light reduction" of the LED being the most obvious form of degradation. In reality, however, other changes in the various parameters precede the light reduction. Often, degradation precedes total failure. A specific type of degradation failure involves reversible processes caused by current or other stress. These failures can be induced and thus identified through targeted tests, such as temperature cycling tests.

Examples include:

• Electrical interruption
• Bond wire detachment
• Bond wire detachment due to mechanical influences
• Bond wire detachment due to chemical influences
• Electrical short circuit
• Short circuit caused by overload
• Short circuit caused by ESD damage
• Degradation
• ESD damage
• Chip aging
• Excessive barrier temperature

Source: https://www.elektroniknet.de/automotive/wirtschaft/appearsbild-und-ursachen-von-led-errorn.87432.html

Flicker is the so-called flickering of a light source. This flickering occurs because our mains voltage powers the electronic ballast (control gear) at a frequency of 50 Hz, causing the current to change its intensity 100 times per second. Thus, maximum brightness or luminance is always displayed at maximum amplitude, regardless of the polarity in the case of an incandescent bulb.

Another possibility is flicker caused by pulse width modulation, or PWM. PWM is the basic principle behind modern dimmers. In principle, dimming lights is achieved by extremely rapid switching on and off in the millisecond range, which is imperceptible to the human eye. These processes result in frequency-related delays that can manifest as flickering.

A dimmer is simply a regulator that controls the current or voltage. However, this control process involves delays in the millisecond range. We perceive this delay as flickering in the LEDs.

In converters, this is a quality characteristic of the capacitors used. If these are of low quality, the time during which the polarity of the alternating voltage changes cannot be adequately bridged, and a so-called flicker occurs during the polarity transition.

Casambi is an intelligent lighting control system that uses Bluetooth to control LEDs, halogen lamps, or even traditional incandescent bulbs. The major advantage of Casambi is that entire lighting scenes can be programmed and automatically switched on and off using a timer.

Source https://www.lightim.de/lightim-magazin/was-ist-eigentlich-casambi

The forward voltage (also called diffusion voltage) is the most important characteristic of a diode. The forward voltage indicates the voltage at which a semiconductor diode conducts in the forward direction. This means that a diode is not always conducting in the forward direction, but only above a certain forward voltage.

The voltage range in which a diode operates is irrelevant. The anode of the diode only needs to be more positive than the cathode by the threshold voltage when forward-biased. The threshold voltage can therefore be considered a potential.

Source: https://www.elektronik-kompendium.de/sites/bau/0201113.htm

PWM stands for Pulse Width Modulation. LEDs are dimmed by a pulse-width modulated current or voltage. Essentially, the LED is switched on and off very quickly, and the number of switching cycles is called the frequency. LEDs are typically switched or dimmed at a frequency of 200-300 Hz, meaning the LED is switched on and off 200-300 times per second. The "on" state always means 100% brightness.

The longer the time between the two on/off states, i.e., the time the LED is off, the less light it emits. The human eye, with its tendency to slow down, then perceives the LED as dimmed. This is possible because the LED reacts instantly to this switching on and off; that is, it doesn't glow faintly like the filament of an incandescent bulb.