Sequential Electrode Driving for Tunable Liquid Crystal Lenses
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Solution Overview
Problem
Designing optical systems for eyewear, such as glasses, that can accommodate varying eye prescriptions and provide effective vision correction while minimizing errors due to parasitic capacitances and optimizing electrode voltage control.
Innovation Solution
The use of adjustable lenses with liquid crystal cells or other electrically modulated optical materials, where electrodes are strategically arranged and voltage control is managed through digital-to-analog converter circuits and switching circuitry to dynamically adjust the refractive index and phase profile, allowing for customizable lenses that can correct multiple vision defects and adapt to different focal ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If digital-to-analog converter circuits are sequentially coupled to different groups of electrodes to reduce the number of routing lines, then device complexity is reduced, but erroneous voltages may occur due to parasitic capacitances between adjacent fingers
Solution Approach 1:
The patent applies preliminary action by pre-charging electrodes before they are officially activated. Specifically, electrodes in a future group are charged to their target voltage levels before the switching sequence reaches them, so when the switch actually connects to these electrodes, the voltage is already established and stable, preventing erroneous voltages from parasitic capacitance effects.
Solution Approach 2:
The patent uses beforehand cushioning by maintaining continuous voltage on electrodes through overlapping charge cycles. The switching sequence is designed so that electrodes are charged in advance and held at their voltage levels through the timing of sequential operations, cushioning against the harmful effects of parasitic capacitance that would otherwise cause voltage errors during switching transitions.
2Device complexity
If fewer digital-to-analog converter circuits are used to drive more electrodes, then device complexity is reduced, but manufacturing precision requirements increase to avoid erroneous voltages
Solution Approach 1:
The patent reduces manufacturing precision requirements by performing preliminary charging of electrodes before the main switching operation. This advance preparation ensures that when electrodes are connected to digital-to-analog converter circuits, the voltage is already established, reducing the sensitivity to manufacturing variations in switching timing and connection precision.
Solution Approach 2:
The patent employs periodic action through its sequential switching scheme that cycles through groups of electrodes in a repeated pattern. This periodic operation allows the system to use fewer digital-to-analog converter circuits while maintaining voltage control precision, as each converter serves multiple electrodes over time through the periodic sequence, and the regular timing helps compensate for manufacturing variations.
3Adaptability or versatility
If electrodes are driven at different voltages in rapid succession, then adaptability of the lens is improved, but parasitic capacitances cause erroneous voltages
Solution Approach 1:
The patent applies preliminary action by charging electrodes to their required voltage levels before the switching sequence activates them. This advance charging ensures that when electrodes are rapidly switched to different voltage groups, the voltage is already stable and correct, preventing parasitic capacitance from causing erroneous voltages during the rapid succession of voltage changes needed for lens adaptability.
Solution Approach 2:
The patent maintains continuity of useful action by ensuring electrodes remain charged to their target voltages throughout the switching process. The sequential switching scheme with pre-charging creates continuous voltage application without interruption or error, allowing the lens to achieve adaptability through rapid voltage changes while the continuous charging action prevents parasitic capacitance from disrupting the voltage control.
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 enables eyewear to provide precise vision correction for various eye prescriptions, reduces errors from parasitic capacitances, and optimizes electrode voltage control, ensuring effective and adaptable optical performance.
Implementation Method 1
Each liquid crystal cell may include a layer of liquid crystal material interposed between transparent substrates. Control circuitry may apply control signals to an array of electrodes in the liquid crystal cell to adjust a phase profile of the liquid crystal material.
Implementation Method 2
Each adjustable lens may include one or more liquid crystal cells or other voltage-modulated optical material.
Data Source
Figure 1
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AI summary
A pair of eyeglasses may include one or more adjustable lenses. An adjustable lens may include electrically modulated optical material such as one or more liquid crystal cells having a phase profile that is adjusted using patterned electrodes. Digital-to-analog converter circuits may provide voltages to the electrodes. To save space on the lens, a smaller number of digital-to-analog converter circuits may provide voltages to a greater number of electrodes by sequentially coupling and decoupling the digital-to-analog converter circuits to different groups of electrodes, advancing from group-to-group with each clock cycle by a number of electrodes that is less than the number of digital-to-analog converter circuits. At least one of the electrodes in each group may be driven at the same voltage for two consecutive clock cycles to avoid erroneous voltages resulting from the parasitic capacitance between adjacent fingers.