This study fabricates a cross-form microchip in which the two side channels are attached to the main channel via a nanochannel bridge. Ionic depletion and enrichment zones are established on the anodic and cathodic sides of the nanochannel. Results show that the low conductivity within the depletion zone induces a rapid electroosmotic flow, which in turn prompts the generation of vortex flow structures within the depletion zone. Both the lengthening of the depletion bulk charge layer and decrease in length of the diffusion layer as the applied voltage is increased are also demonstrated in this study.

It has been demonstrated that electrical stimulation of the retina can produce visual perception for blind patients suffering from macular degeneration and retinitis pigmentosa. In order to let the retinal chip generate enough electrical stimulation, the near infrared ray source is added to enhance the stimulation current. However, it is a challenge to design a head-mounted display (HMD) that covers both visible and infrared rays. Since the HMD system covers such a broad spectral band, large color aberrations will be induced. In order to eliminate these large aberrations, a mirror system is adopted that will create a no color aberration system. We also use two freeform mirrors (FFMs) to reduce residual aberrations such as spherical aberrations and coma. The FFMs serve as the near-eye viewing optics that magnifies the image which is displayed through a microdisplay. Based on a 0.61 in. microdisplay, the HMD system demonstrates a diagonal field of view (FOV) of 30 degree and an f/# of 3.75, with an exit pupil diameter of 8 mm and eye clearance of 15mm.

The current study presents a method for producing recirculation zones in a straight microchannel using opposing pressure-driven and electrokinetically driven flows. The interaction of these two flow streams causes flow recirculation structures, which restricts the flow passage within the microchannel and causes a nozzle-like effect, thereby increasing the separation distance between particles in the fluid stream. Theoretical and experimental investigations are performed to investigate the effects of the applied electrical field intensity on the flow recirculation size, and the nozzle-like effect, respectively. In general, the results confirm that the proposed approach provides an effective means of achieving particle acceleration and separation distance within straight microchannels, and therefore provides a viable technique for improving particle manipulation and optical detection in conventional microfluidic devices.