Researchers from the Chinese Academy of Sciences, Hong Kong University of Science and Technology, Beihang University and the Hong Kong Polytechnic University have reported the development of a focus-tunable curved imaging system based on an ultrathin perovskite curved image sensor. The device was designed to address the limitations of conventional curved sensors, which cannot adjust their curvature to match the Petzval surface across different focal ranges.
The human visual system and the focus-tunable real-time curved imaging system. (A) Schematic of the human visual system. (B) Schematic of the focus-tunable real-time curved imaging system. Image from: Science Advances
The perovskite image sensor was fabricated with a total thickness of 5.4 μm with a hierarchical mesh design. This architecture allows the device to conform to hemispherical surfaces with varying radii while maintaining mechanical stability during deformation, as the mesh interconnects accommodate local strain. The sensor achieves a low detection limit of 10 nW cm⁻², which is below the sensitivity range of human photoreceptor cells, and maintains a stable dynamic photoresponse.
To ensure durability and resistance to decomposition, parylene C film was employed both as a substrate and as an encapsulation layer, enabling compatibility with standard fabrication processes.
By integrating the sensor with a shape-tunable convex lens, it is possible to adjust both the sensor curvature and lens focal length in coordination. This configuration enables imaging of objects at different distances with reduced optical aberration, closely mimicking the process of visual accommodation. Furthermore, coupling the perovskite curved sensor with a thin-film transistor readout matrix and wireless data module allows real-time acquisition and display of grayscale images.
This work provides a framework for integrating perovskite optoelectronics into advanced imaging platforms capable of more closely emulating natural vision.
