Liquid Lens Curvature Control via Capacitance Feedback
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Solution Overview
Problem
Existing liquid lens control systems struggle to accurately recognize and control the movement and shape of the liquid lens interface in response to electric signals, leading to inefficiencies in autofocus and image stabilization functions.
Innovation Solution
A liquid lens control circuit and method that incorporates a sensor unit to sense the capacitance changes at the liquid lens interface, allowing for precise control of the lens curvature through a feedback loop and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a liquid lens is used to adjust focal length electrically, then the device size is reduced and power consumption is lowered, but the control precision and interface recognition accuracy deteriorate
Solution Approach 1:
The patent implements a feedback control system where a sensor unit continuously monitors the capacitance of the liquid lens interface and feeds this information back to a controller. The controller adjusts the voltage applied to individual electrodes based on the detected interface position, enabling precise control and accurate recognition of the liquid lens interface state, thereby resolving the measurement precision deterioration issue.
Solution Approach 2:
The patent replaces traditional optical sensing methods with electrical capacitance sensing. By measuring the capacitance between electrodes and the liquid lens interface, the system achieves accurate interface detection without complex optical components, maintaining measurement precision while keeping the device compact and power consumption low.
2Reliability
If traditional lens-driving devices are used for AF and image stabilization, then control reliability is improved, but power consumption increases and device thickness increases
Solution Approach 1:
The patent replaces mechanical lens-driving devices with an electrically controlled liquid lens system. The liquid lens uses voltage applied to individual electrodes to control the interface shape and position, eliminating moving mechanical parts. This substitution maintains control reliability through precise electrical control while significantly reducing power consumption and device thickness.
Solution Approach 2:
The patent utilizes the electro-hydrodynamic properties of liquid crystals or conductive liquids to achieve lens control. By applying voltage to individual electrodes, the electrical field manipulates the liquid interface shape and position, providing reliable control without mechanical actuators, thereby reducing power consumption and overall device thickness.
3Measurement precision
If multiple sensing circuits and ADCs are used to measure interface capacitance, then measurement precision is improved, but device complexity and size increase
Solution Approach 1:
The patent divides the liquid lens interface into multiple regions, each associated with individual electrodes. By measuring capacitance for each electrode independently, the system achieves comprehensive interface coverage and high measurement precision. The segmented approach allows precise localization of interface position and shape changes across different areas of the lens.
Solution Approach 2:
The patent employs a single sensor unit and ADC that can measure capacitance for multiple electrodes sequentially or simultaneously through multiplexing. This multi-functional approach enables comprehensive interface monitoring without requiring separate sensing circuits for each electrode, thereby reducing device complexity and size while maintaining high measurement precision through multiple measurement points.
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
Enables quick and accurate adjustment of the liquid lens curvature, improving autofocus and image stabilization performance while minimizing the size of the control circuit and reducing power consumption.
Implementation Method 1
recognize a state of the interface included in the liquid lens through a change of a capacitance
Implementation Method 2
liquid lens that electrically adjusts a curvature of an interface between two types of liquids
Data Source
AI summary
A lens curvature variation apparatus according to an embodiment includes: a liquid lens including a common electrode and a plurality of individual electrodes; a lens driver configured to apply a voltage to the common electrode and the plurality of individual electrodes; a sensor unit configured to sense an interface of the liquid lens; an AD converter configured to convert an analog signal corresponding to the interface output from the sensor unit into a digital signal; and a controller configured to control the lens driver based on a signal output from the AD converter, wherein the plurality of individual electrodes includes a first group and a second group each including two or more individual electrodes, wherein the sensor unit includes a first sensor unit connected to a first individual electrode among individual electrodes of the first group; and a second sensor unit connected to a second individual electrode among individual electrodes of the second group; and wherein the controller includes a controller for controlling the lens driver to adjust the voltage applied to each of the individual electrodes included in the first group and the second group based on the signal output from the AD converter.