What is Swiss Super-LumiNova® ?
Swiss Super-LumiNova® or SLN is a ceramic-based compound that absorbs natural sun and artificial ultraviolet light, projecting luminescence in the dark; it is non-radioactive and harmless. It behaves like a light storage battery, photons are absorbed from the UV-light and with the (newly gained) energy, electrons are lifted into a higher energetic state. It is the energy in the photons that activate the SLN, causing the SLN’s electrons to enter a higher energy state. When these electrons return to their “normal” energy state they emit photons (light) in return. In other words when the ultraviolet light disappears, the absorbed energy is then emitted as visible light over the following hours. This process (charging, storage, emission of light) can be repeated infinite times with SLN and has no age limit.
In the Swiss watch industry, it is used by companies to provide this luminescent property to dials, bezels and hands as well as diverse other components. However, there is no limit to the uses for SLN.
SLN is an aluminate, (in chemistry, an aluminate is a substance containing an oxyanion of aluminium such as AlO2-). It is very hard, in the Mohs hardness rating at 9, diamond being rated at 10. (The Mohs' hardness scale was developed in 1822 by Frederich Mohs. 1 - is the softest until 10 being the hardest). It measures the relative hardness between minerals being able to scratch each other. SLN is non-toxic, non-radioactive.
There exists eight emission colours of Swiss Super-LumiNova®. These are independent of the colours of the SLN viewed in daylight that can be made in virtually any Pantone colour reference.
When the crucible is removed from the oven after baking the composition has completely changed, both in consistency and luminescent activity. The material has separated into small cubes, it has become luminescent and close to diamond in hardness.
At this stage the luminescent properties of the material is fully activated. If one takes a UV-light and shines it at the material, it immediately absorbs the UV energy in seconds, and emits it in darkness.
The bags below contain powders with different light emissions. Watches can in essence be made that during the day, their indexes, numbers and hands are all of the same colour due to the pigments added to the Swiss Super-LumiNova, but at night they glow multiple different colours due to the varying light emissions.
The second step is to measure the afterglow light intensity of the powders. A sample of SLN powder is placed in the black box and charged for 20 minutes by an ultra-violet light source, then when the light is turned off, a camera system on top of the box measures the length of time and intensity structure that the afterglow emissions follow and last for.
In addition to requests for a SLN product simply by colour reference, clients also send examples of components they want to replicate. Below is an example of a hand that was sent to RC Tritec and one of the comparison cards that was developed whilst the recipe was being developed to match to the colour.