Micromirror Array Leverage Mechanism for Compact Scanning

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Solution Overview

Problem

Micromechanical micromirror arrangements with piezo drives face limitations in scanning large areas with compact designs, as they require significant voltage-induced deformation to achieve substantial mirror deflections, which can be inefficient and mechanically challenging.

Innovation Solution

The micromechanical micromirror array employs a configuration where the first and second pivoting wing devices extend along the third axis beyond the axis of rotation, utilizing a leverage effect to achieve larger rotations with smaller deflections, and incorporates a quadruple drive system with piezoelectric or electromagnetic drives for enhanced deflection and robustness, along with a sensor device for detecting elastic movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If piezoelectric drives are used to deflect micromirrors, then compact design is achieved, but large area scanning requires significant voltage-induced deformation which is mechanically challenging

Engineering Contradiction:
Improvecompact designVSAvoidmechanical stress from voltage-induced deformation
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The pivoting wing devices extend along the third axis beyond the axis of rotation (second axis), creating a three-dimensional leverage mechanism. This dimensional extension allows small deflections in the third axis to produce large rotations about the second axis, achieving large scanning angles without requiring large piezoelectric deformations

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The system uses elastic deformation of the pivoting wing devices through spring means to achieve dynamic rotation of the micromirror. The elastic elements allow the structure to flex and rotate smoothly, converting small piezoelectric actuations into large mirror deflections through the leverage effect

Inventive Principle:
Principle #15Dynamics

2Speed

If the pivoting wing devices are extended along the third axis beyond the axis of rotation, then larger micromirror rotations are achieved with small deflections, but the device complexity increases

Engineering Contradiction:
Improverotation angle achievementVSAvoidstructural complexity of pivoting wing devices
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The micromirror device is divided into multiple functional segments: the micromirror itself, the pivoting wing devices, the spring means, and the piezoelectric actuators. This segmentation allows each component to perform its specific function efficiently, with the extended pivoting wings providing leverage while the springs provide elastic restoration

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pivoting wing devices combine multiple functions: they serve as both the structural element that provides leverage for rotation and as the elastic element that stores and releases mechanical energy. The extension beyond the rotation axis merges the leverage arm function with the elastic deformation function in a single integrated structure

Inventive Principle:
Principle #5Merging (Combining)

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 configuration allows for larger rotations of the micromirror device with relatively small deflections of the pivoting wing devices, enabling efficient scanning of large areas while maintaining a compact design and providing robust and space-saving solutions for micromechanical systems.

Implementation Method 1

The piezo drives used use the effect of the piezo effect. As soon as a voltage is applied to a piezoelectric layer, it deforms.

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3698195B1Micromechanical micromirror array
Publication Date: 2023.03.08 ROBERT BOSCH GMBH
  • EP3698195B1 patent drawingFigure 1a
  • EP3698195B1 patent drawingFigure 1b
  • EP3698195B1 patent drawingFigure 1c

AI summary

The invention provides a micromechanical micromirror array and a corresponding operating method. The micromechanical micromirror array is equipped with a frame (1) having a cutout (AS), a micromirror device (10) suspended from the frame (1) in the region of the cutout (AS) in a first plane (x, y), a first pivoting vane device (2a) suspended from the frame (1) and projecting into the region of the cutout (AS), said first pivoting vane device being coupled to the micromirror device (10) via a first spring device (4a), a second pivoting vane device (3a) suspended from the frame (1) and projecting into the region of the cutout (AS), said second pivoting vane device being coupled to the micromirror device (10) via a second spring device (4b), a first drive device (81a) for deflecting the first pivoting vane device (3a) along a first axis (z) running perpendicular to the first plane (x, y), and a second drive device (82a) for deflecting in antiphase the second pivoting vane device (3b) along the first axis (z). The micromirror device (10) can be resiliently rotated out of the first plane (x, y) about a second axis (x) by the deflection in antiphase of the first pivoting vane device (2a) and the second pivoting vane device (3a). The first pivoting vane device (2a) and the second pivoting vane device (3a) are designed such that they extend, on a first side of the micromirror device (10), beyond the second axis (x) in the direction of a third axis (y) running substantially perpendicular to the second axis (x).