A low cost CMOS polarimetric ophthalmoscope scheme for cerebral malaria diagnostics

Abstract

In this chapter, we present a low cost CMOS polarimetric ophthalmoscope scheme enabling the capture of the retinal abnormalities that are unique to cerebral malaria. The proposed technology, which can be integrated into cellphones, offers the basis for quick and non-invasive screening of cerebral malaria. In addition, we report a micropolarizer array technology exploiting "guest-host" interactions in liquid crystals for visible imaging polarimetry. The proposed technology enables the fabrication of high resolution (5μm x 5μm pixel pitch) micropolarizer arrays with submicron thickness (0.95μm) to provide for larger light collection angles and reduced optical cross-talk. With the "host" nematic liquid crystal molecules photo-aligned by sulfonic azo-dye SD1, we report averaged major principal transmittance and polarization efficiency (PE) of 80.3% and 0.863, respectively across the 400nm - 700nm visible spectrum range. The proposed fabrication technology is simple and cost-effective, requiring only a single ultraviolet-exposure of the spin-coated "guest-host" mixture through a "photoalignment master". © 2012 IFIP International Federation for Information Processing.