Piezoelectric Adaptive Mirror Monolithic Combs
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Solution Overview
Problem
Existing adaptive mirrors face a compromise between the distribution pitch and stroke of piezoelectric bars, with a minimum distribution pitch of 3 mm being impractical for applications requiring smaller pitches and similar stroke sizes, typically in the order of micrometers.
Innovation Solution
The adaptive mirror employs monolithic combs of piezoelectric material with teeth forming bars, utilizing the transverse piezoelectric effect to achieve a smaller section and lower distribution pitch, where each monolithic bar has a square section and is secured to a base formed by joining the backs of multiple combs, allowing for a smaller distribution pitch while maintaining sufficient stroke.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If composite piezoelectric bars are used to achieve sufficient stroke, then the number of stacked elements must be increased, but this requires a large surface area for each element which prevents achieving a low distribution pitch
Solution Approach 1:
The patent changes the piezoelectric effect parameter from direct effect (stacking elements in series) to transverse effect (using lateral expansion). This allows achieving the same stroke with a single monolithic element of smaller cross-section, enabling distribution pitch reduction to 1mm while maintaining several micrometers stroke
Solution Approach 2:
The patent segments the piezoelectric structure into monolithic combs with multiple teeth, where each tooth is a独立的 actuator bar. This segmentation allows compact arrangement with 1mm pitch while each tooth maintains sufficient stroke through the transverse piezoelectric effect
2Ease of operation
If the number of stacked piezoelectric elements is increased to achieve greater travel, then the surface area of each element must be large, but this makes it impossible to obtain a low distribution pitch
Solution Approach 1:
The patent utilizes the transverse piezoelectric effect parameter instead of the direct effect, allowing a single monolithic element to achieve the required travel without stacking. This reduces the number of elements and electrodes from multiple stacked components to a single comb structure with manageable complexity
Solution Approach 2:
The patent merges multiple piezoelectric teeth into monolithic combs that are joined together. This combining approach achieves the collective travel capability of multiple stacked elements while using a compact single-layer structure that enables 1mm distribution pitch
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 design enables a smaller distribution pitch of piezoelectric bars while achieving a stroke of several micrometers, specifically demonstrated with a distribution pitch of 1 mm and a stroke of 3 micrometers, enhancing the adaptability of the mirror for various optical applications.
Implementation Method 1
piezoelectric actuators, in the form of bars, secured to a rigid base by one of their ends and provided with electrodes by means of which electric voltages can be applied to said piezoelectric actuators to generate electric fields therein
Implementation Method 2
each monolithic bar of piezoelectric material is provided, on opposite longitudinal faces, with two electrodes to form one of said actuators
Data Source
Figure 1~2a
Figure 3~4
AI summary
The mirror has bar-shaped piezoelectric actuators joined to a rigid base by one of ends and provided with electrodes in virtue of which electrical voltages are applied to the actuators to generate electric fields. Monolithic combs of piezoelectric material are placed side by side, and attached to each another, where each comb includes teeth forming monolithic bars. Back of the mirror forms a slice of a base, and each of the monolithic bars is provided with two electrodes on opposing longitudinal faces to form one of the actuators.