The design of optical systems for digital cameras is complicated by the requirement that the image surface be planar, which results in complex and expensive optics. We analyze a compact optical system with a curved image surface and compare its performance to systems with planarimage surfaces via optics analysis and image system simulation. Our analysis shows that a curved image surface provides a way to lower the number of optical elements, reduce aberrations including astigmatism and coma, and increase off-axis brightness and sharpness. A method to fabricate curved image focal plane arrays using monolithic silicon is demonstrated.

Despite progress in the performance of image sensors, comparatively little work has focused on overcoming the limitations of planar image sensor arrays. We present a technique to construct curved monolithic silicon structures that can be processed using standard silicon processing prior to curving. The process relies on microstructuring of a monolithic silicon die using a deep reactive ion etch process. This technique can be used to build curved integrated circuits such as image sensors for more compact cameras with improved optical performance.

unrolls last and is given by imax=t/D, where t is the thickness of the spiral ribbon defined by the fabrication process and D We have developed an approach to build large-area electronics the diameter of the innermost spiral winding (Fig. 3). For from monolithic silicon integrated circuits. The method used t=2gm, and assuming a maximum allowable strain of Fax=1%, deep reactive ion etching to structure a monolithic silicon a minimum node diameter of D=200m is required. If finer substrate into a stretchable, two-dimensional, wired network lithography is used to define thinner ribbons, the silicon that can be expanded to cover large planar or curved surfaces islands can be shrunk proportionally. In Fig. 4, a typical force to realize high-performance, large-area, monolithic silicon vs. displacement calculated using finite-element simulations electronics in a cost-effective manner. This approach has ( Fig. 3) is shown. The length of the spiral ribbon can be applications in sensing, smart materials, electronic textile, adjusted depending on the desired density of silicon after RFID tag and microconcentrator solar cell manufacturing.stretching.

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We have developed a curvable photovoltaic monolithic retinal implant that requires no electrical power or data connection. The implant consists of a two-dimensional network of miniature silicon solar cells that directly stimulate the retina when illuminated by a goggle system. A MEMS process isolates adjacent pixels and makes the arrays curvable allowing them to conform to the shape of the retina. Motivation and Approach