The Foldscope is a fully functional microscope that can be laser- or die-cut out of paper for around 50 cents.
This bookmark-sized microscope can be assembled in minutes, includes no mechanical moving parts, packs in a flat configuration, is extremely rugged and can be incinerated after to safely dispose of infectious biological samples. With minor optics modifications, the microscope can be designed for brightfield, multi-flourescence or projection microscopy, or specialized to identify specific pathogens.
Foldscope design, components and usage. (A) CAD layout of Foldscope paper components on an A4 sheet. (B) Schematic of an assembled Foldscope illustrating panning, and (C) cross-sectional view illustrating flexure-based focusing. (D) Foldscope components and tools used in the assembly, including Foldscope paper components, ball lens, button-cell battery, surface-mounted LED, switch, copper tape and polymeric filters. (E) Different modalities assembled from colored paper stock. (F) Novice users demonstrating the technique for using the Foldscope. (G) Demonstration of the field-rugged design, such as stomping under foot. Credit: arXiv:1403.1211 [physics.optics]