Piezoelectric Drive Torsional Hinge Mirror Bracket With Isolation Slot
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Solution Overview
Problem
The stress loading from attaching a mounting bracket to a using device causes a shift in the resonant frequency and increases the power required to drive MEMS scanning mirrors with piezoelectric drive elements, particularly in battery-powered devices, affecting image scanning.
Innovation Solution
A combination pivoting mirror and support bracket assembly with an isolation slot between the mounting and mirror portions, allowing the bracket to be secured to a using device with minimal impact on the piezoelectric devices, featuring a mounting area for the bracket and a surface for piezoelectric devices that extend outwardly, with torsional hinges anchoring the mirror above the bracket surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the bracket is securely attached to the using device, then the mounting stability is improved, but the stress on piezoelectric devices increases causing resonant frequency shift
Solution Approach 1:
The bracket is divided into two separate portions by an isolation slot: a first portion for mounting to the using device and a second portion for mounting the piezoelectric devices. This segmentation allows the mounting stress to be isolated to the first portion, preventing it from transmitting to the piezoelectric devices mounted on the second portion, thus maintaining resonant frequency stability while ensuring mounting security.
2Reliability
If the bracket size is increased to reduce stress on piezoelectric devices, then the stress reduction is improved, but the device size increases
Solution Approach 1:
Instead of increasing the overall bracket size, the bracket is segmented into two portions separated by an isolation slot. This allows stress isolation without requiring additional space, as the slot creates a stress-free zone for the piezoelectric devices while the first portion can be compact for secure mounting.
Solution Approach 2:
The isolation slot acts as an intermediary element between the mounting portion and the piezoelectric device mounting portion. It mediates the stress transmission by creating a discontinuity in the bracket structure, preventing stress from the mounting area from reaching the piezoelectric devices, thereby protecting them without requiring a larger bracket.
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 significantly reduces stress on piezoelectric devices, maintaining the resonant frequency and reducing the power required to drive the mirror, while keeping the mounting bracket size unchanged, thus optimizing energy efficiency and image scanning performance.
Implementation Method 1
A plurality of piezoelectric devices are mounted to the second portion of the bracket and extend outwardly from a surface of the bracket
Implementation Method 2
The mirrors are designed such that the pivotal resonance of the mirror about its torsional hinges matches the selected scanning frequency for the mirror
Implementation Method 3
a pair of torsional hinges extending from the central mirror portion radially outward to an anchor frame
Data Source
AI summary
A combination pivoting mirror and support bracket has a bracket for supporting a pivoting mirror assembly and for attaching the combination to a using device. The bracket has first and second edges. A first portion of the bracket defines a mounting area for fixedly securing the first portion to the using device, and a second portion of the bracket is for mounting the pivoting mirror. An isolation slot is formed in the bracket and located between the first portion of the bracket and the second portion of the bracket. A plurality of piezoelectric devices are mounted to the second portion of the bracket and extend substantially orthogonal to a surface of the bracket. A pivoting mirror has a pair of torsional hinges for pivotally supporting a reflective surface. Each hinge of the pair extends away from the reflecting surface and along a selected axis to an anchor portion. The anchor portion of each hinge is mounted to a distal end of at least one of the piezoelectric devices to suspend the pivoting mirror above the surface of the bracket.