A Magnetically-Coupled Micromachined Electrostatic Energy Harvester Driven by Eye Blinking Motion

Pourshaban, Erfan; Karkhanis, Mohit; Deshpande, Adwait; Banerjee, Aishwaryadev; Ghosh, Chayanjit; Kim, Hanseup; Mastrangelo, Carlos H.

doi:10.1109/transducers50396.2021.9495499

Cited by 10 publications

(7 citation statements)

References 13 publications

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“…Two other sets of measurements were taken at 45-degree and 90-degree rotation from magnetic north to show the invariability of the proposed approach to head movements. The vergence angle is next calculated from the calibrated magnetometer data using (26).…”

Section: Magnetometer Measurements and Discussion Of Resultsmentioning

confidence: 99%

“…Equation (26) essentially requires that the external field that is being measured is pointing along the same direction at both magnetometer locations. This is satisfied for most situations but may not be true in the presence of magnetic objects very close to the eyes.…”

Section: Magnetometer Measurements and Discussion Of Resultsmentioning

confidence: 99%

“…Smart contacts require several subsystems for their realization. Some key components are varifocal lenses [12]- [14], various types of power sources like wireless power transfer [15]- [18], metal-air batteries [19]- [21], solar cells [22]- [25] and other bio-fluid based energy harvesters [26]- [28], object distance sensors [29]- [31], electronic components and flexible interconnects between these subsystems [32] and soft packaging to encapsulate these components [33], [34]. All these subsystems must conform to the small form factor of a thin shell in contact with the eye and operate with very little electrical power consumption as possible as energy storage is, in general proportional to the system volume, and for this application, the thickness is in the order of 1 mm or less.…”

Section: Introductionmentioning

confidence: 99%

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Ultralow Power On-the-Eye Vergence and Distance Sensing Through Differential Magnetometry

et al. 2023

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We demonstrate the realization of a very low energy, on-the-eye vergence-type distance ranger based on sensing of a locally-uniform vector field, specifically the earth's magnetic field. This ranging method is passive, only requiring measurement of the magnetic field vector at both eyeballs utilizing magnetometer chips placed on the eye scleral regions. The eye vergence angle and range distance are calculated from these two vector quantities. The method can obtain a range reading with as little as 118 nJ of energy consumed per eye for 3.3V and 50 nJ when operated at 1.9V. This method is thus suitable for applications where energy storage is very limited such as in smart contacts vision correcting microsystems.

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Section: Magnetometer Measurements and Discussion Of Resultsmentioning

confidence: 99%

Section: Magnetometer Measurements and Discussion Of Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ultralow Power On-the-Eye Vergence and Distance Sensing Through Differential Magnetometry

et al. 2023

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“…Accordingly, the urgent need to develop a sustainable power supply for SCLs is recognized more than ever. Conventional Li-ion batteries, , radio power scavenging, and electrostatic generators , were already reported as the proposed strategies to supply power to SCLs. However, all these methods suffer from serious shortcomings, which make them unsuitable for the practical realization of SCLs.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, due to the limited available area on the SCL, the reading range (<10 cm) and the power output of the wireless power transfer are too low . Furthermore, our group already showed the possibility of converting the mechanical motion of eye blinking to electricity through the design and fabrication of two different types of electrostatic generators. , Electrostatic generators operate based on the capacitance gradient (Δ C ). , Hence, the device’s surface should be electrically charged to enhance the Δ C . An external charging source is not an appropriate option because it requires a separate power source always connected to the harvester.…”

Section: Introductionmentioning

confidence: 99%

Flexible and Semi-Transparent Silicon Solar Cells as a Power Supply to Smart Contact Lenses

Pourshaban

Banerjee

Deshpande

et al. 2022

ACS Appl. Electron. Mater.

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Supplying electric power to wearable IoT devices, particularly smart contact lenses (SCLs), is one of the main obstacles to widespread adoption and commercialization. In the present study, we have successfully designed, fabricated, and characterized semi-transparent, self-supported, and flexible single crystalline silicon solar cells using a single-sided micromachining procedure. Optical, mechanical, and electrical simulations, together with the practical measurements, verify the application of our developed solar cells to be mounted on a limitedfootprint and flexible SCL. The 15 μm-thick silicon solar cells conformally fit on a dome-shaped contact lens (ROC = 8 mm) without any mechanical and electrical degradation. This homojunction photovoltaic device containing an array of microholes exhibits a V oc , J sc , and maximum power density of 504 mV, 6.48 mA cm −2 , and 1.67 mW cm −2 , respectively, at 25% visible light transparency under an AM1.5 one sun condition. Furthermore, the measurements were conducted under low-intensity indoor light conditions and resulted in a maximum power output of 25 and 42 μW cm −2 for the 50 and 25% transparent solar cells, respectively.

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Power Scavenging Microsystem for Smart Contact Lenses

Pourshaban,

Karkhanis,

Deshpande

et al. 2024

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On‐the‐eye microsystems such as smart contacts for vision correction, health monitoring, drug delivery, and displaying information represent a new emerging class of low‐profile (≤ 1 mm) wireless microsystems that conform to the curvature of the eyeball surface. The implementation of suitable low‐profile power sources for eye‐based microsystems on curved substrates is a major technical challenge addressed in this paper. The fabrication and characterization of a hybrid energy generation unit composed of a flexible silicon solar cell and eye‐blinking activated Mg–O2 metal–air harvester capable of sustainably supplying electrical power to smart ocular devices are reported. The encapsulated photovoltaic device provides a DC output with a power density of 42.4 µW cm−2 and 2.5 mW cm−2 under indoor and outdoor lighting conditions, respectively. The eye‐blinking activated Mg–air harvester delivers pulsed power output with a maximum power density of 1.3 mW cm−2. A power management circuit with an integrated 11 mF supercapacitor is used to convert the harvesters’ pulsed voltages to DC, boost up the voltages, and continuously deliver ≈150 µW at a stable 3.3 V DC output. Uniquely, in contrast to wireless power transfer, the power pack continuously generates electric power and does not require any type of external accessories for operation.

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A Magnetically-Coupled Micromachined Electrostatic Energy Harvester Driven by Eye Blinking Motion

Cited by 10 publications

References 13 publications

Ultralow Power On-the-Eye Vergence and Distance Sensing Through Differential Magnetometry

Ultralow Power On-the-Eye Vergence and Distance Sensing Through Differential Magnetometry

Flexible and Semi-Transparent Silicon Solar Cells as a Power Supply to Smart Contact Lenses

Power Scavenging Microsystem for Smart Contact Lenses

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