Highly curved image sensors: a practical approach for improved optical performance.

Area of Science:

• Optics and Photonics
• Materials Science
• Semiconductor Manufacturing

Background:

• Curved focal surfaces offer significant optical and size advantages for imaging systems.
• The mass production of high-quality curved image sensors has been a major limitation.

Purpose of the Study:

• To demonstrate the feasibility of forming commercial silicon CMOS image sensors into accurate, highly curved optical surfaces.
• To develop a novel process for mass-producing curved image sensors without compromising functionality.

Main Methods:

• A pneumatic forming process using a pressure membrane was employed to shape thinned CMOS image sensors.
• Careful control of forming-mold design, membrane elasticity, and friction minimized wrinkling and stress.
• The process allowed for a threefold increase in spherical curvature compared to previous methods.

Main Results:

• Successfully thinned and formed commercial silicon CMOS image sensors into highly curved shapes with undiminished functionality.
• Prototype cameras with curved sensors achieved exceptional resolution (3220 LW/PH at f/1.2) and nearly 100% relative illumination.
• The process was shown to be compatible with various sensor formats, including APS-C sized dies.

Conclusions:

• The pneumatic forming process provides a viable method to bridge the gap between planar CMOS technology and ideal non-planar imaging components.
• This innovation enables a new generation of ultra-high-performance, manufacturable digital imaging systems for diverse applications.
• Curved image sensors hold significant potential for advancing scientific, industrial, and artistic imaging.