Piezoelectric Variable Aperture Assembly for Fast Light Control
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Solution Overview
Problem
Traditional electro-mechanical variable apertures in imaging devices, such as barcode scanners, are limited by the mass and inertia of moving parts, leading to slow aperture changes and inaccurate light control, making them inadequate for high-speed applications.
Innovation Solution
A variable aperture assembly using a piezoelectric annular bending disc and a polymer disc, coupled with a cover glass, allows for fast and accurate aperture size adjustment without moving parts by deforming the polymer disc through applied voltage, controlling the area of contact between the convex portion of the polymer disc and the cover glass to adjust light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional electro-mechanical actuators are used to change aperture position, then the aperture can be adjusted, but the response speed is slow due to mass and inertia of moving parts
Solution Approach 1:
The patent replaces traditional electro-mechanical actuators with a piezoelectric actuator that uses electrical fields to directly deform the aperture structure. The piezoelectric material changes shape in response to voltage applied across electrodes, eliminating mechanical moving parts and achieving rapid aperture adjustment without the mass and inertia limitations of conventional mechanical systems.
Solution Approach 2:
The patent changes the physical state of the aperture by applying voltage to the piezoelectric material, which alters its dimensional parameters. The voltage applied across the electrodes directly controls the deformation of the piezoelectric element, thereby changing the aperture size in a controlled and rapid manner without mechanical intermediate steps.
2Manufacturing precision
If traditional electro-mechanical actuators are used, then the aperture can be changed, but the accuracy is limited by tolerances and motion variations of moving parts
Solution Approach 1:
The patent eliminates mechanical moving parts that introduce tolerances and motion variations by using a piezoelectric actuator. The piezoelectric material's direct electrical-to-mechanical conversion provides more precise and repeatable aperture positioning, as the deformation is controlled by electrical parameters rather than mechanical tolerances and clearances.
Solution Approach 2:
The piezoelectric actuator inherently provides precise deformation control through its material properties. The voltage applied across the electrodes directly determines the amount of deformation, eliminating the need for complex mechanical linkages and reducing the impact of manufacturing tolerances on the final aperture position.
3Productivity
If traditional electro-mechanical apertures are used, then the aperture can be adjusted, but they respond slowly and are inadequate for high speed applications
Solution Approach 1:
The patent replaces slow electro-mechanical actuators with a piezoelectric actuator that has no moving parts. The piezoelectric material responds directly to voltage changes with negligible delay, enabling the aperture to be adjusted at speeds suitable for high-performance imaging applications where rapid aperture changes are required.
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 rapid and precise control of light intake, overcoming the limitations of traditional electro-mechanical apertures by providing a deformable aperture assembly that supports high-speed imaging applications.
Implementation Method 1
a piezoelectric annular bending disc defining a center opening and having opposing first and second major sides... The bending disc is selectively deformable toward the first major side when a voltage is applied across first and second electrodes of the bending disc
Data Source
AI summary
A variable aperture assembly is provided. For example, a variable aperture assembly comprises a piezoelectric annular bending disc, a polymer disc coupled to the bending disc, a cover glass coupled to the polymer disc, and a light absorptive fluid contained in a space between the polymer disc and the cover glass. The bending disc is selectively deformable when a voltage is applied. The polymer disc has a convex portion curved toward the cover glass. An area of contact between the convex portion and the cover glass defines an optical aperture. A size of the optical aperture is controlled by controlling a size of the area of contact between the convex portion and the cover glass. The size of the area of contact between the convex portion and the cover glass is controlled by controlling the voltage applied to the bending disc.