Researchers in Korea have developed an ultra-thin lens, which is only one tenth of the thickness of existing refractive lenses, and laid the foundation for drastically reducing the size of smartphone cameras.
On the 2nd, Pohang University’s Department of Mechanical Engineering and Chemical Engineering Prof. Joon-Seok Noh team worked with Professor Heon Lee’s team in the Department of Materials Science and Engineering, Korea University, and Seung-Hoon Han’s Master Team in Imaging Device Lab, Samsung Electronics Advanced Institute of Technology. It revealed that it has developed an infrared ultra-thin meta lens and a technology to mass-produce it.
This is a study that suggested the possibility of overcoming the limitations of large and heavy existing optical devices using metamaterials, and was published in the American Chemical Society’s (ACS) nano science journal’ACS Nano.’
The lens that collects light is a key component of the latest electronic devices and optical devices such as smartphones and DSLR cameras, but conventional refractive lenses are large and heavy, and their performance is limited when the volume is reduced.
In particular, in the case of a smartphone camera that uses a composite lens consisting of 8 to 9 refractive lenses, it is difficult to reduce the thickness of the composite lens, resulting in a so-called’katuktu’ problem in which the rear camera of the smartphone protrudes.
Moreover, DSLR cameras need to develop thin and light lenses with a refractive lens weight of at least 500g to over 4kg.
The research team studied metamaterial-based lenses to develop lenses with high performance and small volume.
Metamaterials can freely control various optical properties, such as sonic and ultra-high refraction, which are not found in existing materials, and researches to implement new optical devices such as ultra-thin flat lenses, high-resolution holograms, and transparent cloaks are being actively conducted. However, the conventional metamaterial processing has a disadvantage that the process speed is slow and the cost of the produced metamaterial is very high because electron beam lithography is used.
In this study, the research team developed a one-step printing technology that can form a new nanocomposite-based nanocomposite-based material that has optical properties suitable for metamaterial realization and is free to form, and can be molded in a single process.
The nano molding material was made by mixing silicon nanoparticles with excellent refractive properties with a photosensitive resin that hardens when exposed to light. The research team said that this nano-molding material can replace the existing meta-material material because it can widely control the optical properties according to the type and concentration of the nano-particles, and the material cost is significantly cheaper.
In addition, the one-step printing technology can produce metamaterials at a speed of more than 100 times faster than conventional electron beam lithography, and can implement metamaterials on curved and flexible substrates, so it can be applied to wearable devices.
Using this silicon nanocomposite and printing technology, the research team confirmed that it is possible to replace the existing refractive lens through an imaging experiment by fabricating an ultra-thin metal lens with a thickness of 1 μm (micrometer), which is less than one hundredth of a hair, and combining it with an actual optical system. He explained that he also verified the possibility of practical application.
Prof. Joon-Seok Noh said, “The thickness of this ultra-thin metalens is only one tenth of the thickness of an existing infrared refractive lens with the same optical properties, so it will be able to solve the problems caused by large and heavy refractive lenses.” “In the future, infrared endoscopes, CCTV, night vision It will be applicable to various fields such as,” he said.
Reporter Yoon Seung-hoon [email protected]
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