Search for: All records

We propose an artificial iris to tackle sensitivity caused by photophobia. This artificial iris is made with a twisted nematic cell sandwiched between two linear polarizers. The light attenuation performance of a commercial TNC was compared with TNCs made for smart contact lenses. 

We demonstrate the implementation of a low-power, low-profile, varifocal liquid-crystal Fresnel lens stack suitable for tunable imaging in smart contact lenses. The lens stack consists of a high-order refractive-type liquid crystal Fresnel chamber, a voltage-controlled twisted nematic cell, a linear polarizer and a fixed offset lens. The lens stack has an aperture of 4 mm and thickness is ∼980 µm. The varifocal lens requires ∼2.5 V_RMSfor a maximum optical power change of ∼6.5 D consuming electrical power of ∼2.6 µW. The maximum RMS wavefront aberration error was 0.2 µm and the chromatic aberration was 0.008 D/nm. The average BRISQUE image quality score of the Fresnel lens was 35.23 compared to 57.23 for a curved LC lens of comparable power indicating a superior Fresnel imaging quality. 

We demonstrate fabrication of tunable flexible refractive Fresnel liquid-crystal lens using PET for Smart Contact Lens System. We show focus tunability of 1.9D at 1.1V_RMSusing voltage and pulse width modulation lens tuning techniques. 

By stacking multiple thin, LC filled lenses based on refractive Fresnel geometry, we experimentally demonstrate a fast response, low-power, and low-profile adaptive optical system that is suitable for integration with a smart contact lens system. 

Using high-performance LC (5CB) filled microfabricated refractive Fresnel chambers, we experimentally demonstrate a thin low-profile adaptive optical system with very high analog tunability (15.5 D) that can be integrated with an adaptive smart contact-lens system. 

This article reports the fabrication, characterization, implementation, and microsystem integration of micromachined flexible silicon solar cells to supply electric power to smart contact lenses. Single silicon solar cell shows the open circuit voltage (V oc ) of 0.5 and 0.55 V Under indoor and outdoor lighting conditions, respectively. The V oc enhanced to 1.25 and 1.65 V after making series connections between three cells. The maximum power output of 50 µW and 2.7 mW are recorded under indoor and outdoor lighting conditions. Furthermore, a power management IC is used to boost up the voltage to 3.3 V and efficiently store or use the generated energy. 

One of the essential requirements of any flexible substrate electronic system is the availability of reliable, high density, fine pitch interconnects between components. In this work, we demonstrate a high-toughness two-layer (aluminum, N-doped polysilicon) composite wiring scheme. The top aluminum layer carries most of the current while the polysilicon underlayer electrically bridges any cracks present on the top aluminum induced by flexing thus maintaining electrical conductivity even at very high stresses. When composite and Al control wires on a flexible tape were subject to 4000 cycles of bending, we observed that Al control wires fracture at a 2.5 mm radius of curvature but the composite wires maintain electrical conduction with an increased resistance. 

Using high-performance LC (E7) filled microfabricated refractive Fresnel chambers, we experimentally demonstrate a thin low-profile adaptive optical system with high analog tunability (2.1 D) that can be integrated with an adaptive contact-lens system. 

We report a thin film wearable aluminum-air battery that utilizes the flow of a biological fluid (eye tear) as a moving electrolyte. When the eye blinks, the eye-tear fluid comes into contact with two metal electrodes, and it produces spontaneous redox reactions, which generate an electric current when connected to a load. In this paper, we demonstrate that a 5×5 mm2 tear-activated Al-air battery is capable of providing maximum energy of 45 μJ per eyeblinking cycle. Furthermore, we investigate the effect of different air-breathing electrodes, including gold, platinum, and silver, on the battery's performance. Results demonstrate that the battery's maximum voltage and current outputs are 1 V and 220 μA while using Pt as the cathode. The moving biofluid Al-air battery with the Pt cathode charges up a 10 μF capacitor in 10 s. Furthermore, load line analysis shows a maximum deliverable load power density of 64 μW·cm-2 for this device.