Micromirror Array for Free-Form Illumination Patterns
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Solution Overview
Problem
Existing apparatuses for generating illumination patterns are limited to planar or single-curved light sheets, making it difficult to measure flow velocities and directions near structured walls or in three-dimensional spaces, as they scatter when brought close to wall elevations, leading to useless measurement signals.
Innovation Solution
A system using a micromirror array to diffract coherent light, generating two-dimensional free-form illumination patterns with low divergence angles, allowing for adjustable and complex light beam shapes, including curved lines and waves, which can be optimized for measuring flows near structured walls and enabling three-dimensional measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a planar or single-curved light sheet is used, then the construction is simple, but the measurement capability near structured walls is lost due to scattering
Solution Approach 1:
The light sheet is segmented into multiple independently controllable light beams using a micromirror array with multiple micromirrors. Each micromirror can be tilted independently to direct light along different paths, allowing the light sheet to be divided into multiple segments that can be individually positioned and shaped to follow complex wall geometries without scattering issues
Solution Approach 2:
The light sheet is transformed from a static planar or single-curved structure into a dynamic, reconfigurable illumination pattern. By rapidly tilting micromirrors in the micromirror array, the system can dynamically adjust the shape, position, and curvature of light beams to match complex wall structures, enabling reliable measurements near structured walls while maintaining construction simplicity
2Adaptability or versatility
If refractive optics with movable parts are used to generate non-planar light sheets, then three-dimensional measurement is enabled, but the construction effort and complexity increase very high
Solution Approach 1:
The patent replaces complex mechanical refractive optics with movable parts with a micromirror array consisting of multiple small mirrors that can be tilted independently. This substitution eliminates the need for large movable optical components while achieving the same three-dimensional measurement capability through electronic or piezoelectric control of micromirror tilting angles
Solution Approach 2:
The system achieves three-dimensional measurement capability by changing the tilting angle parameter of individual micromirrors in the array. By controlling the tilt angles of multiple micromirrors, the system can generate light beams with different directions and curvatures, enabling three-dimensional flow measurement without requiring complex mechanical optical systems
3Measurement precision
If a planar light sheet is brought close to wall elevations, then velocity gradient measurement near the wall is improved, but the light sheet scatters and the measurement signal becomes useless
Solution Approach 1:
Instead of using a single planar light sheet that scatters at wall elevations, the system segments the illumination into multiple narrow light beams. Each beam can be independently directed and shaped to follow the wall contour, maintaining close proximity to the wall for accurate velocity gradient measurement while avoiding scattering by adapting to wall elevations
Solution Approach 2:
The system dynamically adjusts the shape and position of light beams by controlling micromirror tilting angles in real-time. This allows the light sheets to adapt to wall elevations and maintain optimal measurement conditions without scattering, improving velocity gradient measurement accuracy near structured walls
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 precise measurement of flow velocities and directions in complex geometries and three-dimensional spaces with high energy efficiency and minimal scattering, improving the accuracy of flow measurements and reducing construction complexity.
Implementation Method 1
a micromirror array for diffracting planarly incident coherent light comprising a plurality of micromirrors, which are each tiltable around at least one axis by the control means
Implementation Method 2
a microlens array having a plurality of microlenses, wherein the microlenses comprise a common Fourier plane, which is disposed congruently with a Fourier plane of the collecting means
Data Source
AI summary
Apparatus for generating a two-dimensional illumination pattern of light beams, including: controller; a micromirror array; illuminator; collector; and a microlens array; wherein the controller is configured for tilting the micromirrors such that in the Fourier plane of the collector, intensity maxima of light collected by the collector can be generated, wherein the intensity maxima are each allocated to one of the microlenses, wherein from the respectively generated intensity maximum one of the light beams is generated by the respectively allocated microlens.