Contact Lens Charging Circuit With Wear Detection and Overvoltage Cutoff
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Solution Overview
Problem
There is a need for a charging circuit suitable for electronic contact lenses that can efficiently charge the batteries while preventing damage from overvoltage and ensuring safe operation when the lenses are being worn.
Innovation Solution
The charging circuit includes an overvoltage protection circuit with a shorting switch and an optically-enabled voltage multiplier, which detects overvoltage conditions and prevents damage by interrupting the power supply, and a disabling circuit that enables charging only when the lens is not being worn, using photodiodes to detect the presence of a charger and control the charging process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the charging circuit charges the batteries continuously, then the charging efficiency is improved, but the risk of overvoltage damage increases
Solution Approach 1:
The charging circuit incorporates an overvoltage detection mechanism that continuously monitors the battery voltage during charging. When the voltage reaches a predetermined threshold, the circuit automatically interrupts the charging current, preventing overvoltage damage. This feedback-based control enables continuous charging operation while maintaining safety through real-time voltage monitoring and automatic current interruption.
2Power
If the charging circuit operates with high power, then the charging speed is improved, but the heat generation and safety risks increase
Solution Approach 1:
The charging circuit employs periodic charging cycles with automatic current interruption at predetermined time intervals or when voltage thresholds are reached. This periodic operation allows the battery to charge at high power during active phases while providing regular pauses that prevent excessive heat accumulation and reduce safety risks, thereby enabling high-power charging with controlled thermal management.
3Ease of operation
If the charging circuit allows charging during wear, then the convenience is improved, but the safety and component integrity are compromised
Solution Approach 1:
The charging circuit incorporates a wear-detection mechanism that automatically determines whether the contact lens is being worn based on electrical connection status or optical detection. The circuit enables charging only when the lens is detected to be in the charging case (not worn), and automatically disables charging when wear is detected. This self-service functionality ensures safety and component integrity without requiring user intervention to check wear status.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents damage from overvoltage and ensures safe charging of the electronic contact lenses by disabling charging when worn, maintaining the integrity of the components and ensuring reliable operation.
Implementation Method 1
using photodiodes to detect the presence of a charger and control the charging process
Implementation Method 2
an optically-enabled voltage multiplier, which detects overvoltage conditions and prevents damage by interrupting the power supply
Data Source
AI summary
An electronic contact lens. The electronic contact lens includes an energy storage device and a charging circuit for charging the energy storage device. The electronic contact lens is configured to disable the charging circuit when the contact lens is worn.