Tunable Eyeglass Lenses With Digital Voltage Selection Circuitry
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Solution Overview
Problem
Designing eyewear with tunable lenses that can accommodate varying eye prescriptions and provide satisfactory optical performance is challenging, as existing solutions often require excessive analog circuitry and complex signal paths, limiting their effectiveness and practicality.
Innovation Solution
The use of adjustable lenses with liquid crystal cells and digital voltage selection circuitry, which includes an array of multiplexers and operational amplifiers to reduce signal paths and analog circuitry, allowing for dynamic adjustment of the refractive index profile through controlled voltage application to electrodes, thereby accommodating different eye prescriptions and optical needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional analog circuitry is used to control liquid crystal cells in tunable lenses, then the lenses can accommodate different eye prescriptions, but the device complexity and number of signal paths increase excessively
Solution Approach 1:
The patent replaces traditional analog voltage control circuitry with a digital microcontroller-based system. The microcontroller generates control signals that drive multiplexers, which in turn select appropriate voltages from a reduced set of analog voltage sources. This substitution of analog control with digital control reduces the complexity of signal paths and circuitry while maintaining the ability to accommodate different eye prescriptions through software-controlled lens power adjustment.
Solution Approach 2:
The patent implements a universal control architecture where a single microcontroller handles multiple functions: generating control signals for multiple liquid crystal cells, managing multiplexer operations, and adapting to different prescription requirements. The multiplexer system serves as a universal voltage selection mechanism that can route any of the limited analog voltage sources to any required electrode, eliminating the need for dedicated analog circuitry for each control function.
2Manufacturing precision
If more analog circuitry is added to provide precise voltage control for liquid crystal electrodes, then optical performance improves, but the area available on the lens increases
Solution Approach 1:
The patent extracts the complex analog voltage generation and control functions from the lens assembly and relocates them to an external microcontroller unit. Only the essential voltage selection components (multiplexers) and a minimal set of voltage sources remain on the lens. This extraction reduces the area occupied on the lens while maintaining precise voltage control through the digital control system that communicates with the multiplexers.
Solution Approach 2:
The patent changes the control paradigm from continuous analog voltage adjustment to discrete digital voltage selection. Instead of using complex analog circuitry to generate a continuous range of voltages, the system uses a limited set of discrete voltage levels that are selected digitally by the microcontroller through multiplexers. This parameter change from continuous to discrete control reduces the hardware requirements on the lens while maintaining sufficient precision for optical adjustment.
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 with adjustable lenses that can dynamically adjust to various eye prescriptions, reducing the need for excessive analog circuitry and simplifying signal paths, resulting in improved optical performance and practicality for users with different vision defects.
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
AI summary
A pair of eyeglasses may include one or more adjustable lenses that are each configured to align with a respective one of a user's eyes. The adjustable lenses may each include electrically modulated optical material such as one or more liquid crystal cells, each having a phase profile that is adjusted using patterned electrodes. Analog voltages may be provided to the patterned electrodes through variable-resistance conductive paths that are each coupled to a subset of the patterned electrodes. Digital voltage selection circuitry may be used to select which analog voltage to apply to each of the variable-resistance conductive paths from a predetermined set of analog voltages that are generated off of the lens. The digital voltage selection circuitry may include an array of multiplexers, each of which selects a desired voltage based on control signals received from digital control circuitry such a shift register and/or a decoder.