AGC Asahi Glass (AGC) of Tokyo reports that the company has developed a quartz lens for deep ultraviolet LEDs. The company claims that with this product, the manufacturing processes of deep ultraviolet LED can be significantly simplified and the capital investment in manufacturing equipment and processes can be reduced. AGC intends to begin prototyping in the third quarter of 2018 and has scheduled the start of mass production for 2019.
UV and Deep UV LEDs are known to be superior to mercury lamps because they do not contain mercury a chemical that is extremely toxic to the human body and the environment. Also, deep ultraviolet LEDs offer an extremely potent disinfecting action.
AGC says adhesive joining the lens and window degrades due to UV light.
However, the company says that current deep ultraviolet LEDs often have some design issues such as the transparent adhesive joining the lens and the window material that is expensive and easily degrades due to ultraviolet light. The company also says that the current solder for joining the package and the window is so hard that the thermal stress from the difference of coefficient of thermal expansion (CTE) between package and window directly attacks the interface between them.
AGC notes that clients must employ large-scale deoxygenation equipment during the hermetic sealing process. Despite this, the CTE difference can cause ultraviolet LED products to crack and leak air.
However, AGC Asahi Glass says its newly developed a quartz lens for deep ultraviolet LEDs can help solve this. The quartz lens integrates the quartz window material and the lens with the firm’s proprietary technology so that a transparent adhesive is not needed. In addition, the “special solder” developed by the company is already overlaid so that clients can join lens and cavity by simply heating and pressing in the atmosphere, without needing large-scale deoxygenation equipment. Furthermore, the “special solder” is soft to ease the thermal stress due to the difference of CTE. So, it will not crack or allow air leak.