Liquid Lens Feedback Control for Focal Precision
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Solution Overview
Problem
Existing liquid lens technologies face challenges in accurately controlling the position of the fluid interface to achieve desired focal properties due to factors like temperature variations and manufacturing imperfections, which affect the capacitance and position of the fluid interface, making it difficult to achieve precise focal lengths and optical image stabilization.
Innovation Solution
A liquid lens system with a chamber containing immiscible fluids, where electrodes are used to control the position of the fluid interface based on voltage differentials, and a feedback control system adjusts voltage signals based on capacitance measurements and temperature, using a signal generator, sensor circuitry, and temperature sensors to maintain precise focal lengths and optical image stabilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage signals are applied to control the fluid interface position, then focal length adjustment is achieved, but temperature variations and manufacturing imperfections cause capacitance changes that reduce positioning precision
Solution Approach 1:
The patent implements a feedback control system where sensor circuitry continuously measures the capacitance between electrodes and the first fluid, which indicates the fluid interface position. The controller receives these capacitance measurements and adjusts the voltage signals applied to the electrodes to maintain the desired fluid interface position despite temperature variations and manufacturing imperfections. This closed-loop feedback mechanism resolves the contradiction by using real-time capacitance data to compensate for environmental and manufacturing variations, thereby maintaining both positioning precision and focal length accuracy.
Solution Approach 2:
The patent utilizes capacitance as a measurable parameter that changes with fluid interface position, temperature, and manufacturing variations. By monitoring capacitance changes and using them as feedback to adjust control voltages, the system adapts to parameter variations. The common electrode grounded to ground impedes charge buildup, stabilizing the electrical parameters. This approach transforms the problematic parameter changes (temperature, manufacturing imperfections) into useful feedback signals that enable precise compensation and maintain reliable focal length control.
2Stability of the object's composition
If a common electrode is grounded to impede charge buildup, then electrical stability is improved, but the system complexity increases due to additional grounding requirements
Solution Approach 1:
The common electrode serves multiple functions: it provides a reference potential for voltage differential control, collects charge to prevent buildup in the chamber, and acts as a grounding point for the entire liquid lens system. By making the common electrode multi-functional, the patent achieves electrical stability without proportionally increasing system complexity. The same electrode structure that is necessary for voltage control also performs the charge management function, eliminating the need for separate charge dissipation components.
3Measurement precision
If sensor circuitry with sampling capacitors and current mirrors is used to detect fluid interface position, then measurement accuracy is improved, but the circuit complexity and manufacturing difficulty increase
Solution Approach 1:
The patent uses the electrical properties of the liquid fluids themselves (capacitance, dielectric constant) as the sensing mechanism, eliminating the need for complex mechanical or optical sensors inside the chamber. The sensor circuitry measures electrical capacitance between electrodes and the first fluid, which naturally varies with fluid interface position. This approach leverages the inherent electrical properties of the liquid system rather than requiring separate sensing components, thereby improving measurement accuracy while keeping the manufacturing complexity manageable through standard PCB fabrication techniques for the electrode and sensor circuits.
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 system effectively adjusts the fluid interface position to achieve precise focal lengths and optical image stabilization, compensating for temperature and manufacturing variations, thereby improving the accuracy and reliability of the liquid lens in camera systems.
Implementation Method 1
a position of the fluid interface is based at least in part on one or more voltage differentials between the one or more electrodes and the common electrode
Implementation Method 2
The common electrode can be electrically coupled to ground to impede charge from building up in the liquid lens
Implementation Method 3
The sensor circuitry can be configured to output one or more voltage values that are indicative of capacitance between the one or more electrodes and the first fluid
Data Source
AI summary
A liquid lens can be coupled to ground, such as to impede charge from building up in the liquid lens during operation thereof. For example, an electrode that is in electrical communication with a conductive fluid of the liquid lens can be coupled to ground. A switch can be used to selectively couple the liquid lens to ground, such as for discharging the liquid lens. An electrode can be selectively coupled to ground and to driving signals using a switch. In some cases, drive signals can be provided to electrodes other than the grounded electrode for driving the liquid lens. In some cases, the liquid lens can be driven using feedback control based on one or more measured parameters indicative capacitance between a fluid and one or more electrodes in the liquid lens.