THE LED FILAMENT
or the LED light string
WHAT IS A LED FILAMENT AND HOW DOES IT WORK?
The LED filament is a LED filament on which individual diodes are applied using COB (Chip On Board) technology. The carrier material is e.g. sapphire glass (transparent), ceramic or copper. These materials have good heat-conducting properties from the ground up and have a certain cooling capability.
In order to generate a broad light spectrum, diodes of different colors are bonded to the substrate and additionally coated with a fluorescent layer. This layer is the yellow, visible outer sheath of the filament. Depending on the composition of the fluorescent material and the arrangement of the diodes, different light colours can be produced. The SEGULA LED filaments are coated all around with the fluorescent layer, which means a large radiation angle, i.e. an almost omnidirectional radiation. If the filaments are only coated on one side, the angle is reduced and the lumen yield is also reduced.
In order to achieve the optical effect of the filament, the individual diodes are applied and connected in series, in contrast to SMD technology. At both ends of the filament there is an electrical contact to apply the voltage.
Another component of ALL LED filament lamps is a small, usually invisible power supply unit built into the base. This converts the AC voltage of the power supply network into DC voltage, which is necessary for the operation of LED lamps.
In SEGULA lamps we additionally use a small capacitor which bridges the wave troughs of the emitted light. Thus we can reduce the so-called “flicker” to a minimum.
Thermally conductive gases, which are filled into the piston, ensure constant cooling of the filament. Constant cooling ensures a long service life and a largely constant luminosity. This is because the semiconductor crystals of the LED are very sensitive to heat and must be cooled constantly.
To achieve a maximum lumen yield of up to 4000 lumens, we at SEGULA use ceramic filament (COC – Chip On Ceramic). This material is very suitable because it has very good thermal conductivity and relatively large diodes can be applied. Many products of the SEGULA Bright Line are equipped with this technology.
The further development – SOFT LED FILAMENT
In 2017 the world novelty of the “Soft Filament” comes on the LED light source market and the optics of the incandescent lamp is almost reached. The rigid carrier materials, such as ceramics or sapphire glass, are being replaced by flexible materials. The so-called “Blue Diamond” silicone-based polyester film is very flexible and allows rounding up to a minimum diameter of approx. 10mm. The shape of the filaments is thus almost unlimited and the appearance is now actually reminiscent of the classic tungsten filament, which we all know. Until 2017, this filament was only used in bulb lamps in order to guarantee constant cooling through the gassing.
WORLD NEWNESS – Soft Filament “PLUS”
The revolution is on its way! The Soft Filament “PLUS”. With this technical innovation, the heat sinks are placed directly on the LED filament and dissipate the heat from the diodes. They look like little wings on the sides of the LED filament. Thus we are no longer dependent on the glass bulb and cooling gases. Completely new styles and designs are possible all at once and are realized by SEGULA in the Art Line!
Another positive side effect of this technology: a much higher lumen yield is possible due to the better and more constant cooling directly at the filament.
The Soft Filament “PLUS” is not only used in the free design, but also within the other series to take advantage of the positive properties. The innovative filament also unfolds its full potential in the beautifully shaped bulb lamps of the Design Line!