Constructed by heterogeneous integration of electronic and optical units, current artificial compound eyes (ACEs) have limited resolution and high construction complexity on curvy surface. Though both can be alleviated using monolithic integration, hitherto the lack of progress can be attributed to the difficulty in resolving incompatibility issues when integrating the photo-sensors and the transistors.

Constructed as an array of pixels and each consisting of metal-oxide thin film transistors (MO-TFTs), a hydrogenated amorphous silicon photodiode (PD), and a structured optical path, this work builds a monolithic integrated ACE system to solve the issues. The ACE design, process and characterization, and application are further explored.

ACE optical units are designed with anticipated an...[ Read more ]

Constructed by heterogeneous integration of electronic and optical units, current artificial compound eyes (ACEs) have limited resolution and high construction complexity on curvy surface. Though both can be alleviated using monolithic integration, hitherto the lack of progress can be attributed to the difficulty in resolving incompatibility issues when integrating the photo-sensors and the transistors.

Constructed as an array of pixels and each consisting of metal-oxide thin film transistors (MO-TFTs), a hydrogenated amorphous silicon photodiode (PD), and a structured optical path, this work builds a monolithic integrated ACE system to solve the issues. The ACE design, process and characterization, and application are further explored.

ACE optical units are designed with anticipated angular field of view, inter-ommatidial angle, resolution, and cross-talk prevention, controlled by the proposed mathematical relationships, and further for motion-tracking on the planar and cylindrical ACE surface. ACE In-pixel circuit consisting of an amorphous silicon photodiode, a one-stage amplifier, and scan TFT is proposed for PD signals amplification and active-matrix addressing.

The monolithic integration processes of each pixel component on the planar and flexible ACE array are developed. When integrated with PD, a protection layer is suggested to protect the TFTs from hydrogen diffusion and radiation damage. The performances of the optical and electrical units on planar and flexible ACE are characterized. With the proposed circuit, the signal strength can be boosted by around 6.7 times. Visualized patterns and light source tracing are demonstrated using a planar ACE array and a 200ppi flexible ACE array, respectively.

The planar ACE system is applied in motion detection and proximity pattern recognition. The motion tracing along the x-, y-, and z-axis and on the x-o-y plane are demonstrated based on the designed resolution. For proximity pattern recognition, three finger patterns are identified with 95% predicting accuracy by constructed neural networks and fabricated ACE.