a recent article by ee news europe examined the growing uv-c disinfection market, which uses short-wavelength ultraviolet light to kill bacteria and combat the spread of pathogens, and thermal management needs of handheld uvc disinfection devices.

the article explains the best solutions for cooling uvc led. (wikimedia commons)

the article noted, “led technology is about to revolutionize the uvc disinfection market by enabling small, robust and portable applications that are not possible using traditional uvc technologies. however, as the technology gets smaller and the power gets higher one major challenge the industry needs to overcome is effective thermal management.”

uvc disinfection has been limited at present by the use of mercury lamps, but led technology has made the lights far safer, smaller, and more robust. the article claimed that the uvc market could jump from $7 million today to more than $610 million by 2021.

according to john cafferkey, marketing manager at cambridge nanotherm, who wrote the article, “the size and robustness of uvc led technology means that such leds could even be embedded within devices themselves, turning them into self-disinfecting devices. these factors open up a host of new applications.”

these applications could range from household or business use to hospitals and other medical uses. this could also lead to the easier sterilization of water anywhere in the world, which is a growing problem in areas that lack centralized infrastructure and with growing pollution issues.

“uvc led technology holds the potential to prevent millions of deaths every year,” cafferkey wrote.

but, in order for uvc disinfection to reach its potential, thermal management has to be front and center. cafferkey noted that uvc leds convert only 5 percent of power into light, which means that 95 percent is converted into heat that needs to be dissipated.

he added, “the size of uv leds is too small to allow for any significant loss of heat through ambient radiation or convection. the only way heat can be removed is through conduction through the back of the led to the pcb and then to the ambient atmosphere via a heat sink. it stands to reason that the pcb on which the led is mounted must have a high thermal conductivity.”

traditional metal-clad pcbs are not an option, so cafferkey suggests a new technique from cambridge nanotherm that uses electro-chemical oxidation to form a layer of alumina ceramic that is microns thick on the surface of an aluminum pcb.

“this acts as an electrically-isolating dielectric layer,” cafferkey said, “preventing the circuit from shorting out against the aluminum heat spreader. alumina isn’t the most thermally-effective substance, but because the layer is extraordinarily thin it conducts heat extremely effectively.”

read the full article at http://www.eenewseurope.com/design-center/thermal-implications-small-portable-uv-led-disinfection.