The National Institute of Information and Communication Technology of Japan has developed the first "high directionality" deep ultraviolet LED

Recently, a research team led by Dr. Shinichiro Inoue, Director of the Future Institute of Information and Communication Technology at the National Institute of Information and Communication Technology in Japan, successfully developed the world's first highly directional deep ultraviolet LED without optical devices by using nano optical structure technology to control the light distribution angle.

 It is understood that the newly developed deep ultraviolet LED proves that by combining nano optical structure technology with micro LED structures, the light distribution angle of emitting deep ultraviolet light can be precisely controlled without the need for optical lenses, and it can be collimated to the beam shape. This structure can effectively improve the light extraction efficiency of deep ultraviolet LEDs. It has been proven that it can not only control the light distribution angle, but also significantly increase the light output (about 1.5 times).

 According to the introduction, deep ultraviolet LEDs are expected to be used to inactivate aerosol viruses floating in the air, and can also be used as light sources for wireless communication that are not affected by sunlight background noise. This achievement is expected to efficiently irradiate high-intensity deep ultraviolet light only where needed without the use of costly lenses or optical components, suppress unnecessary diffusion of deep ultraviolet light, reduce exposure risks to the human body, and significantly improve the safety, efficiency, and productivity of deep ultraviolet LEDs.

  The research group has been actively promoting the research and development of deep ultraviolet LEDs and striving to achieve their applications. Deep ultraviolet LED has a high inactivation effect on viruses and bacteria, and is expected to become an innovative tool for controlling contact and aerosol transmission infections. In addition, the use of deep ultraviolet LEDs with wavelengths not exceeding 280 nanometers in optical wireless communication technology is expected to greatly expand the applicability of high-speed optical wireless communication in outdoor environments, as it can avoid the influence of solar background noise.

  In the practical application of this deep ultraviolet LED for surface and space sterilization, as well as free space optical communication, technology is required to selectively illuminate deep ultraviolet light only in the areas where it is needed to ensure the safety of the human body and others. Generally speaking, the light emitted by light-emitting diodes diffuses in various directions, so far, the distribution angle of light has been controlled through externally installed lenses and optical components. However, for deep ultraviolet LEDs, deep ultraviolet light is absorbed by ordinary optical glass lenses, so it is necessary to use high-purity synthetic quartz lenses with high transparency in the deep ultraviolet region. This leads to extremely high costs for the entire system.

  Considering the widespread use of deep ultraviolet LEDs for disinfection and communication applications in the future, it is necessary to create a technology that can control the distribution angle of light through a single deep ultraviolet LED chip, without the need for costly lenses or optical components, and can effectively illuminate the areas that need to be illuminated with safe and high-strength deep ultraviolet light.

  In this study, the research team successfully developed a deep ultraviolet LED using nano optical structure technology that can control the light distribution angle without the need for optical devices . By combining the nanoscale phase type Fresnel zone plate structure formed on the luminescent surface of aluminum nitride (AlN) with the micro LED structure of aluminum gallium nitride (AlGaN), optical radiation can be controlled without the need for optical lenses, thus achieving control of the beam shape (FWHM:<10 nm). The study also found that this structure can effectively improve the light extraction efficiency of deep ultraviolet LEDs, achieve control of light distribution angle, and significantly increase their light output (about 1.5 times).

  This achievement proves for the first time in the world that the light distribution angle of deep ultraviolet LEDs usually spreads in all directions, without the need for costly lenses or optical components, and can be controlled at an extremely narrow angle. This technology is expected to broaden the application range of optical systems utilizing deep ultraviolet LEDs, from disinfection to a wide range of fields such as medical, sensing, environmental, optical processing, and solar blind spot wireless communication applications, and significantly improve their safety, efficiency, and productivity.