MEMS Mirror Contour Sensor for Extended Depth of Field
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Solution Overview
Problem
Conventional structured light sensing systems have limited depth of field and do not generate three-dimensional data for feature extraction and form measurement, resulting in inaccurate contour sensing and metrology.
Innovation Solution
The implementation of a structured light sensor system that incorporates a multi-pixel MEMS mirror array to maintain a Scheimpflug tilt condition, allowing for focused imaging over a larger depth of field and generating 3D data for feature extraction and form measurement, using a system with a projection system, imaging system, and control module that projects and captures light patterns to determine surface contours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional structured light sensing systems are used, then the system structure is simple, but the depth of field is limited and 3D data cannot be generated
Solution Approach 1:
The patent replaces conventional mechanical focusing systems with a MEMS mirror-based optical system. The MEMS mirrors dynamically adjust the focus plane to maintain the Scheimpflug condition, enabling extended depth of field without requiring complex mechanical focus adjustment mechanisms. This substitution of mechanical focusing with electro-optical control resolves the contradiction between depth of field and system complexity.
Solution Approach 2:
The patent changes the optical parameter configuration by implementing the Scheimpflug condition through controlled tilt of the image plane relative to the object plane. By adjusting the angular orientation parameters of the imaging system, the system achieves extended depth of field while maintaining a relatively simple overall structure. This parameter-based solution avoids complex mechanical redesign.
2Measurement precision
If conventional structured light sensing systems are used, then the device complexity is low, but the accuracy of contour sensing and metrology is insufficient
Solution Approach 1:
The patent substitutes conventional mechanical measurement systems with an optical-MEMS hybrid system. The MEMS mirrors enable precise control of light paths and focus planes, providing accurate 3D data for contour sensing. This optical substitution delivers higher measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The patent introduces MEMS mirrors as an intermediary component between the light source and the image sensor. These mirrors mediate the optical path to maintain the Scheimpflug condition, enabling accurate measurement of surface contours and 3D features. The intermediary MEMS component enables high precision without requiring complete system redesign.
3Adaptability or versatility
If conventional imaging systems are used, then the system is simple, but 3D data for feature extraction cannot be generated
Solution Approach 1:
The patent creates a multi-functional imaging system where the same optical hardware with MEMS mirrors can capture both 2D images and 3D data. The system can operate in different modes (focus plane adjustment, tilt angle control) to generate various types of optical data. This universality enables 3D data generation capability without requiring entirely separate systems, thus limiting the increase in device complexity.
Solution Approach 2:
The patent introduces dynamic control capabilities through MEMS mirrors that can adjust focus planes and tilt angles in real-time. This dynamic adaptability allows the system to generate 3D data by capturing light at multiple focus planes and orientations. The dynamic reconfigurability of the optical path enables versatile 3D measurement capabilities while maintaining a relatively compact system structure.
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 solution increases the optical signal and accuracy of metrology, enabling more precise contour sensing and feature extraction, particularly in the z-direction, and allows for the generation of 3D point clouds for further processing and modeling.
Implementation Method 1
The set of micro MEMS mirrors are configured to direct the focused light to the image capturing device. The control module is configured to determine a quality of focus of the captured light based on the received data, and to control the set of MEMS mirrors based on the quality of focus to maintain a Scheimpflug tilt condition between the lens plane of focus and the image plane of focus.
Implementation Method 2
The imaging lens system is configured to focus light reflected from the surface using at least one lens
Implementation Method 3
The projection system is configured to project onto the surface either (i) a point of light, (ii) a first plurality of points of light forming a line of light
Data Source
AI summary
A structured light sensor system for measuring contour of a surface includes a control module that coordinates control of both a projection system and an imaging system to operate the structured light sensor system in three different modes. The imaging system is configured to selectively capture an image of light reflected off of the surface. In point mode, the imaging system is on for a first period during which the projection system projects a point of light onto the surface. In line mode, the imaging system is on for a second period during which the projection system projects onto the surface a first plurality of points of light forming a line of light. In area mode, the imaging system is on for a third period during which the projection system projects onto the surface a second plurality of points of light forming a plurality of lines of light.