MEMS Mirror Non-Contact Sensor Compact Optical Train

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Solution Overview

Problem

Existing laser projection systems face challenges in reducing the space envelope for optical components while maintaining beam focus and minimizing distortion, which affects the accuracy of surface mapping and coordinate measurement.

Innovation Solution

A non-contact sensing system utilizing a fiber-coupled laser, a lens package with a collimating lens and beam reducer lenses, a movable micro electro-mechanical system (MEMS) mirror, and a fold mirror to generate and scan a Gaussian distributed optical beam, allowing for precise three-dimensional information acquisition with a compact optical train.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the space envelope for optical components is reduced, then the system becomes more compact, but beam focus control becomes difficult and distortion increases

Engineering Contradiction:
Improvespace envelope for optical componentsVSAvoidbeam focus control and distortion
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The patent employs a movable mirror (MEMS or other movable mirrors) that can be angularly adjusted to scan the optical beam across the measurement area. This dynamic positioning capability allows the system to maintain proper beam focus and orientation despite the reduced space envelope, resolving the contradiction between compactness and precision by making the optical path adaptable rather than fixed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces a fold mirror to redirect the optical beam orthogonally, effectively folding the optical path into a more compact configuration. This dimensional reorganization allows the optical components to be arranged in a minimized space envelope while preserving the necessary beam path length and focus characteristics

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

2Manufacturing precision

If mirrors are tilted to desired angular degrees for proper focusing, then beam focus improves, but space requirements increase

Engineering Contradiction:
Improvebeam focusVSAvoidspace envelope
Core Design Contradiction:
Manufacturing precisionVSVolume of moving object

Solution Approach 1:

The fold mirror redirects the optical beam orthogonally, folding the optical path into a compact configuration that achieves proper beam angles without requiring large linear space for mirror tilting

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

Solution Approach 2:

The movable mirror provides dynamic angular adjustment capability, allowing the system to achieve proper focus angles within a constrained space envelope by electronically controlling mirror orientation rather than requiring fixed mechanical tilt arrangements

Inventive Principle:
Principle #15Dynamics

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 system achieves accurate and efficient three-dimensional coordinate measurements with a minimized optical train length, reducing beam diameter and maintaining beam quality, thereby enhancing measurement accuracy and reducing post-processing time.

Implementation Method 1

a collimating lens operating to convert the optical beam to a collimated optical beam

Methodology Applied
Scientific EffectCollimation: Lens

Implementation Method 2

a beam reducer receiving the collimated optical beam from the collimating lens and operating to reduce a diameter of the collimated optical beam

Methodology Applied
Scientific EffectBeam reduction: Lens

Implementation Method 3

A movable mirror receives the optical beam. The movable mirror is angularly adjusted to scan the optical beam to an area of illumination

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 4

a fold mirror oriented to redirect the optical beam received from the movable mirror orthogonally with respect to the orientation path of the optical beam received at the movable mirror and maintain a round shape of the optical beam

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 5

a diverger lens receiving the optical beam from the movable mirror and increasing a scan angle of the optical beam

Methodology Applied
Scientific EffectDivergence: Lens

Data Source

PatentEP2800945B1Non-contact sensor having improved laser spot
Publication Date: 2019.08.07 PERCEPTRON INC
  • EP2800945B1 patent drawingFigure 1
  • EP2800945B1 patent drawingFigure 2
  • EP2800945B1 patent drawingFigure 3

AI summary

A non-contact sensing system acquiring three-dimensional information includes a laser light source and fiber generating a Gaussian optical beam. A movable mirror is angularly adjusted to scan the beam to an area of illumination. A lens package between the light source and the movable mirror focuses the optical beam to under-fill a movable mirror optical surface and control an optical beam scanned volume. The optical beam reflected by the movable mirror is redirected using a fold mirror orthogonal to an optical beam orientation. The optical beam is maintained Gaussian by the mirrors and lenses. An imaging device having a field of view intersecting the area of illumination receives optical beam image data reflected from the area of illumination. A control module communicating with the imaging device receives an object location in the imaging device field of view from the image data and reports object location data to a coordinate system.