At present, disinfection of water and air is done mainly using mercury lamps. However, because mercury has adverse effects on the human body and the environment, production of mercury lamps may be greatly limited in the future under the Minamata Convention on Mercury. Deep ultraviolet LEDs have a low impact on the environment, extremely strong disinfectant action, and as such are expected to be the next generation light source that replaces the mercury lamp. Market size is projected to be 30 billion yen in 2020*1.

However, current deep ultraviolet LEDs (Fig.2) have some problems. One is about the transparent adhesive joining the lens and the window material. It is expensive and is easily degraded by ultraviolet light. Second is for current solder joining the package and window. Clients must have large-scale deoxigination equipment at the time of hermetic sealing, and ultraviolet LED products have the risk of cracking and air leak because current solder is hard so thermal stress due to difference of CTE between package and window directly attack the interface of package and window.
In order to solve these problems, AGC Asahi Glass has newly developed quartz lens for deep ultraviolet LEDs (Fig.2). This product integrates the quartz window material and the lens with AGC’s proprietary technology so a transparent adhesive is not required. In addition, the special solder developed by AGC is already overlaid so clients can join lens and cavity by simply heating and pressing in the atmosphere, without large-scale deoxigination equipment. Furthermore, AGC’s “special solder” is soft so make ease the thermal stress due to difference of CTE between package and window. So it will not crack or allow air leak. By these means, deep ultraviolet LED manufacturing processes can be greatly simplified and capital investment can be reduced.

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Exhibition Summary