UV-A Led light for new industrial vision applications.
UV-A (400-315 nm) lighting sources have existed for many years. They are also called black lights because of their features, employed for decorative and artistic lighting effects (discotheques, theatres and concerts), diagnostic and therapeutic uses in medicine, the detection of substances tagged with fluorescent dyes, the detection of counterfeit money, the curing of plastic resins, attracting insects and the detection of refrigerant leaks affecting refrigerators and air conditioning systems
This light emission is almost invisible (black light), but when it illuminates an object the result can be very different depending on the nature of the object: illuminating certain materials with UV radiation causes the emission of visible light, causing these substances to glow with various colors.
More recently with the advent of the UV-A leds, this feature has started to be used also in the artificial vision sector in the following industrial application areas:
Material recognition in the sorting sector (plastic, glass, ceramic, etc…);
Reading of barcodes printed with ultraviolet paint;
Defects detection on products encapsulated by transparent plastic
Silicone or glue presence indication in the assembly processes
Detection of defects invisible with other kind of lights in mechanical processing;
Detection of defects in food products (meat, fruit and seed);
Detection of impurities and liquid levels
Recently, together with the continuous requests of the customers, the new need to understand which UV-A wavelength is the most indicated for the application in development has become important for the following reasons:
- Depending on the type of material and sensors used, there is a different visual response;
- The manufacturer of the inks that react to UV-A, often does not declare the optimal wavelength
- The UV-A leds have a very narrow bandwidth (from 9 to 15 nm) and the materials or the pigments have a sensibility that changes a lot with the variation of the wavelength
For this reason, it has been realised a new handy KIT that allows to identify which is the best solution in terms of wavelength and type of UV lighting.
It has also been included a white led light in the KIT, useful as comparison during the evaluation tests.
