MEMS Micro-Mirror Rotation Angle Sensing via Variable Resistance
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Solution Overview
Problem
The precision control of micro-mirrors in light steering systems, such as LiDAR modules, is limited due to variations in fabrication processes and non-idealities, leading to non-uniform rotations and reduced imaging/ranging resolution.
Innovation Solution
An adaptive control system that includes a semiconductor integrated circuit with a microelectromechanical system (MEMS) and measurement structures with variable electrical resistance, allowing for precise measurement and adjustment of micro-mirror rotation angles to ensure uniformity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fabrication process variations are reduced to improve micro-mirror uniformity, then manufacturing precision improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent implements a feedback mechanism where sensors measure the actual rotation angle of each micro-mirror, and control signals are adjusted based on these measurements to compensate for fabrication variations. This allows achieving uniform rotation without requiring extremely precise fabrication processes.
Solution Approach 2:
The patent changes the control parameter from fixed voltage to dynamically adjusted voltage based on measured rotation angle. By measuring the actual rotation and adjusting the control voltage accordingly, the system compensates for fabrication variations and achieves uniform micro-mirror rotation.
2Measurement precision
If measurement structures are added to each micro-mirror assembly to enable precise rotation angle detection, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent makes the connection structure serve multiple functions: it provides mechanical support for the micro-mirror and simultaneously acts as a sensor to detect rotation angle. This eliminates the need for separate measurement structures, reducing device complexity while maintaining measurement precision.
Solution Approach 2:
The patent merges the mechanical connection structure with the sensing function by incorporating a sensor within the connection structure. This integration allows the same component to fulfill both structural and measurement roles, reducing overall device complexity.
3Stability of the object's composition
If control signals are adjusted for each micro-mirror to compensate for rotation variations, then rotation uniformity improves, but control system complexity increases
Solution Approach 1:
The patent implements a feedback control system where the actual rotation angle of each micro-mirror is measured and used to adjust the control signal. This feedback mechanism enables individual compensation for each micro-mirror while using a standardized control architecture, managing complexity through systematic feedback processing.
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 adaptive control system improves the precision and uniformity of micro-mirror rotations, enhancing the imaging and ranging resolution by accurately determining and adjusting the rotation angles, thereby improving the overall performance of light steering systems.
Implementation Method 1
an electrical resistance of the measurement structure being variable based on a rotation angle of the micro-mirror
Implementation Method 2
the micro-mirror can be rotated to reflect (and steer) light from a light source towards a target direction
Data Source
AI summary
In one example, a light detection and ranging (LiDAR) module is provided. The LiDAR module includes a microelectromechanical system (MEMS), a substrate on which the MEMS is formed, and one or more measurement circuits. The MEMS includes an array of micro-mirror assemblies. One or more micro-mirror assemblies of the array of micro-mirror assemblies further includes a measurement structure connected to the micro-mirror, an electrical resistance of the measurement structure being variable based on a rotation angle of the micro-mirror. The one or more measurement circuits are configured to: determine the electrical resistance of the measurement structure of the one or more micro-mirror assemblies; and provide the determined electrical resistance to enable measurement of a rotation angle of the micro-mirror of the one or more micro-mirror assemblies.