Liquid Lens Voltage Control Circuit for Low-EMI Camera Modules
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Solution Overview
Problem
Portable devices with camera modules using liquid lenses face issues with electromagnetic interference (EMI) due to radiation noise from driving voltage generation, which affects wireless communication sensitivity and increases device size.
Innovation Solution
A camera module design incorporating a liquid lens with a voltage control circuit that reduces the driving voltage magnitude, utilizing a first voltage generator, DC bias terminal, and switching units to minimize radiation noise and optimize voltage application, thereby reducing the size of the camera module and enhancing wireless communication sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a liquid lens with high driving voltage is used to adjust focal length, then the lens control precision is improved, but electromagnetic interference and radiation noise increase
Solution Approach 1:
The voltage control is segmented into multiple stages: a first voltage generator provides a base voltage, and a second voltage generator provides an adjustment voltage. This segmentation allows the system to achieve precise focal length control through combined voltage application while keeping individual voltage magnitudes lower, thereby reducing electromagnetic interference and radiation noise compared to using a single high-voltage generator.
Solution Approach 2:
The first voltage generator acts as an intermediary that provides a stable base voltage, while the second voltage generator serves as another intermediary that fine-tunes the voltage. This two-stage intermediary approach enables precise control with lower peak voltages, reducing harmful electromagnetic effects while maintaining control precision.
2Adaptability or versatility
If a lens-moving apparatus is used to perform AF and OIS functions, then the photographing functions are improved, but the device size and power consumption increase
Solution Approach 1:
The patent replaces the mechanical lens-moving apparatus with an electrically-controlled liquid lens system. The liquid lens uses voltage application to directly adjust the curvature of the liquid-liquid interface, enabling autofocus and optical image stabilization functions without mechanical moving parts, thereby significantly reducing device size while maintaining functional versatility.
Solution Approach 2:
The system changes the operational parameter from mechanical position to electrical voltage. By applying different voltages to the liquid lens electrodes, the focal length and lens curvature are dynamically adjusted, enabling AF and OIS functions through electrical parameter control rather than mechanical movement, thus reducing device complexity and size.
3Adaptability or versatility
If a lens-moving apparatus is used for AF and OIS, then the photographing functions are improved, but power consumption increases
Solution Approach 1:
The patent replaces the power-intensive mechanical lens-moving apparatus with an electrically-controlled liquid lens system. The liquid lens requires only electrical voltage application to adjust focus and perform image stabilization, eliminating the need for motors and mechanical actuators, thereby significantly reducing power consumption while maintaining AF and OIS functionality.
4Reliability
If a cover glass is added to protect the lens-moving apparatus, then the device reliability is improved, but the overall thickness increases
Solution Approach 1:
The patent eliminates the mechanical lens-moving apparatus that would require protective cover glass, replacing it with a solid-state liquid lens system. The liquid lens has no moving mechanical parts that need protection, allowing the device to achieve reliability through electrical control while maintaining thin overall thickness without additional protective layers.
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 reduces radiation noise, decreases the size of the camera module, and improves antenna reception sensitivity, enabling smoother video calls and multitasking in portable devices.
Implementation Method 1
research has been conducted on a liquid lens configured to electrically adjust the curvature of an interface between two types of liquids in order to perform the AF function and the OIS function
Implementation Method 2
The DC bias terminal may include a resistor disposed between the output terminal of the first voltage generator and the ground voltage
Data Source
AI summary
The present invention includes a liquid lens; a voltage control circuit, and a switching unit, wherein the liquid lens includes a first plate comprising a cavity in which a conductive liquid and a non-conductive liquid are disposed; a second plate disposed above the first plate; and a third plate disposed below the first plate, wherein the voltage control circuit includes a first voltage generator configured to output a first voltage; and a DC bias terminal disposed between an output terminal of the first voltage generator and a ground voltage, and wherein the switching unit includes a plurality of first switches configured to transmit one selected from among the first voltage and the ground voltage to the plurality of individual electrodes; and a second switch configured to transmit one selected from among the first voltage and the ground voltage to the common electrode.