Piezoelectric Crown Membrane for Compact Optical Focal Length Control
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Solution Overview
Problem
Existing optical devices with deformable membranes suffer from bulkiness, high energy consumption, and poor actuating efficiency, and struggle to maintain optimal optical performance and adjust focal length effectively, especially in varying temperatures.
Innovation Solution
An optical device with a deformable membrane featuring a continuous crown of piezoelectric material and multiple actuators, anchored to the membrane and support, allowing for precise deformation control and temperature compensation, using a combination of piezoelectric bimorphs and thermal bimorphs to manage stress and maintain focal length stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If radial micro-beams are used as actuating means, then the membrane can be deformed to adjust focal length, but the device becomes bulky and energy consumption increases
Solution Approach 1:
The continuous crown of piezoelectric material is segmented into multiple independent piezoelectric actuators arranged radially. Each actuator can be independently controlled to deform specific zones of the membrane, enabling focal length adjustment and optical aberration correction without requiring a bulky single actuator structure
Solution Approach 2:
Different regions of the membrane are actuated by different piezoelectric elements with tailored characteristics. The actuators are positioned and sized to provide localized deformation control, allowing optimal performance for different optical functions (focus adjustment, aberration correction) in different membrane zones
2Ease of operation
If radial micro-beams are used as actuating means, then the membrane can be deformed, but energy consumption upon actuation becomes high
Solution Approach 1:
The actuating function is divided among multiple piezoelectric actuators that can operate independently. Only the necessary actuators are activated for each specific operation (focus adjustment or aberration correction), reducing total energy consumption compared to activating all actuators or using a single large actuator
Solution Approach 2:
The piezoelectric actuators exploit the piezoelectric effect to convert electrical energy directly into mechanical deformation with high efficiency. By controlling the voltage applied to each actuator, precise membrane deformation is achieved with minimal energy input
3Reliability
If a continuous crown of piezoelectric material with multiple actuators is used, then optical performance is improved and focal length adjustment is enhanced, but device complexity increases
Solution Approach 1:
The continuous crown is segmented into multiple standard piezoelectric actuators with identical or similar characteristics. This modular approach simplifies manufacturing and assembly compared to designing custom actuators, while still providing enhanced optical performance through coordinated operation of multiple elements
Solution Approach 2:
The same piezoelectric actuator design serves multiple functions: focal length adjustment, optical aberration correction, and potentially other wavefront modulation tasks. This multi-functionality reduces the need for separate specialized actuators for each function, thereby managing device complexity
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 results in a compact, energy-efficient optical device with improved actuation flexibility, reduced optical aberrations, and the ability to maintain focal length consistency across a wide temperature range, enhancing performance and reducing manufacturing residual stresses.
Implementation Method 1
actuating means for moving the fluid biasing the membrane into an intermediate area between the anchor area and the central area, the actuating means including a continuous crown of piezoelectric material accommodating several piezoelectric actuators
Implementation Method 2
maintaining optimal focal length across a temperature range, and improving optical performance by integrating multiple piezoelectric actuators and thermal bimorph elements
Data Source
AI summary
An optical device with a deformable membrane (2) including an anchor area (2.3) on a support (1) entrapping a liquid or gas fluid, a central area (2.1) reversibly deformable from a rest position, actuating means for moving the fluid (4) biasing the membrane (2) into an intermediate area between the anchor area (2.3) and the central area (2.1), the actuating means include a piezoelectric continuous crown accommodating several actuators (5.1), this crown surrounding the central area (2.1), the actuating means (5) being anchored to the membrane (2) in at least the intermediate area (2.2), the actuating means (5) and the membrane (2) to which they are anchored, forming at least one piezoelectric bimorph (B), the actuating means (5) radially contracting or extending upon actuation so as to generate a movement of said fluid (4) from the intermediate area (2.2) to the central area (2.1) of the membrane (2) or vice versa, aiming at deforming the central area (2.1) with respect to its rest position.