Capacitive Lens Displacement Detection Circuit
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Solution Overview
Problem
Existing optical devices face challenges in safely operating high-intensity light sources due to the risk of retinal damage, necessitating accurate detection and proper positioning of a lens to ensure safe light transmission within eye safety thresholds.
Innovation Solution
Incorporating a capacitive sensing mechanism using electrical traces on the lens and lens holder to form a sense capacitor, allowing for the detection of lens presence and positioning through capacitance sensing, enabling or disabling the light source based on proper alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a lens is added to transmit higher total power safely, then the total power transmission capability is improved, but the risk of retinal damage increases if the lens is not properly positioned
Solution Approach 1:
The patent performs lens positioning verification before enabling the light source to operate. The system checks whether the lens is properly positioned in the lens holder using electrical continuity detection through traces on the lens and lens holder. Only after successful verification does the system enable high-power light transmission, thus preventing retinal damage while allowing high power transmission when safe
Solution Approach 2:
The patent implements a feedback mechanism where the system continuously monitors lens positioning through electrical trace connectivity. The control circuit receives feedback signals indicating whether the lens is properly seated, and adjusts the light source operation accordingly - enabling high power transmission only when proper positioning is confirmed, thereby resolving the contradiction between power transmission and safety
2Measurement precision
If electrical traces are added to the lens and lens holder for detection, then the lens positioning detection accuracy is improved, but the device complexity increases
Solution Approach 1:
The patent makes the electrical traces on the lens and lens holder serve multiple functions: they act as both optical elements (for light transmission) and sensing elements (for positioning detection). This multi-functionality allows the system to achieve accurate lens positioning detection without adding separate sensing components, thereby improving measurement precision while minimizing the increase in device complexity
Solution Approach 2:
The patent merges the optical transmission function and the positioning detection function into a single integrated structure. The electrical traces that are part of the lens assembly are used simultaneously for both light transmission and capacitance sensing, combining multiple functions into unified components rather than adding separate systems
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
This solution provides robust and accurate detection of lens displacement, ensuring safe operation by preventing retinal damage from excessive light intensity, offering improved optical alignment sensitivity and reliability.
Implementation Method 1
the lens includes a first electrical trace; wherein the lens holder includes a second electrical trace; and wherein the first and second electrical traces form electrodes of a sense capacitor
Data Source
AI summary
A lens is positioned to be received by a lens holder. The lens includes a first electrical trace and the lens holder includes a second electrical trace. The first and second electrical traces form electrodes of a sense capacitor. A capacitance of the sense capacitor is sensed. From the sensed capacitance, a determination is made as to whether the lens is present and properly positioned in the lens holder.