Integration of a matrix addressable blue/green LED array with multicore imaging fiber for spatiotemporal excitation in endoscopic biomedical applications

We have developed a micro‐scale endoscopic optical image projection device, integrating an InGaN MQW blue/green two‐dimensional (2D) LED array to a multicore imaging fiber. A scalable matrix addressing scheme was used for the electrical access to individual elements in the densely packed 2D‐LED array. A prototype 10×10 element array was fabricated by specialized device process flow, using deep reactive ion etching and polyimide etch‐back processes for device isolation and planarization. Individual elements of the array have been operated under cw current injection up to 3 kA/cm2, suggesting uncompromised performance and robustness of the planarized device structure. The device was butt‐coupled to a 30,000 pixel multicore image fiber to generate a spatiotemporal pattern of light at the output end of the fiber. As application demonstration, selected illumination patterns have been projected to the eye of Xenopus laevis tadpoles in studies of their developing visual system, as well as optically excitable neural cells in the brain. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)