Technology Focus: Heavy Duty Ultraviolet Filter

When it comes to outdoor detection, there are many challenges when it comes to reliable, robust and stable detection.


One such challenge is to overcome natural ultraviolet (UV) light. UV is electromagnetic radiation with a wavelength that is shorter than that of visible light, but longer than that of X-rays. It is constantly present and can cause chemical reactions such as causing some substances to glow or fluoresce, as well as cellular damage to us, like sunburn or even skin cancer.

The chemical and biological impact UV can have, is dependent on its interactions with organic molecules. There are three categories of UV light; UV-A, which is the longest wavelength and least harmful. This is most commonly associated with black lights, whereby it makes certain substances glow or fluoresce, as described above.

There is also UV-B, which is mainly filtered out by the earth’s atmosphere, but is the cause of sunburn, with prolonged exposure increasing risks of skin cancer and other cellular damage.

Finally, there is UV-C, which is the most harmful but almost completely absorbed by the earth’s atmosphere.

UV light is always present and is particularly strong at high altitude and next to the seaside. In relation to security devices, exposure to such high radiation can reduce performance and in some cases blind PIR lenses.


In order to combat this, Pyronix detectors have a strong UV filter, but how does this help?

An apt metaphor for this is sun cream! In order to protect your skin from the sun, you apply sun cream so that your skin does not absorb UV rays.

UV filters are either individual compounds, or a mixture that absorb or block the UV light. Therefore, the PIR lenses of our outdoor detectors are manufactured with a heavy-duty UV filter or UV stabilising material applied to ensure that their detection capability is not affected and performance is maintained.

Looking at other impacts UV can have on our outdoor peripherals, we have also moulded an ultraviolet stabilising