MEMS Micro-Mirror Array for Multi-FOV Optical Sensor
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Solution Overview
Problem
Existing dual-mode optical sensors with afocal zoom systems require complex mechanical arrangements to adjust field-of-view (FOV), limiting flexibility and efficiency in collecting and focusing light across different optical bands.
Innovation Solution
A multiple FOV optical sensor utilizing a primary mirror with rings of differing curvature and a MEMS Micro-Mirror Array (MMA) that can tip, tilt, and piston in two or three degrees of freedom to reflect light from different FOV rings onto an imaging detector, allowing for focused or blurred image formation without moving optical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an afocal zoom system with moving lenses is used to adjust FOV, then the field-of-view can be varied, but the device complexity increases due to complex mechanical arrangements
Solution Approach 1:
The patent replaces the mechanical lens movement system with a fixed optical system that uses a MEMS micro-mirror array to achieve FOV adjustment. The MEMS mirrors can be electronically controlled to redirect light paths, eliminating the need for complex mechanical lens positioning mechanisms while maintaining the ability to vary the field-of-view.
Solution Approach 2:
The fixed optical system is designed to perform multiple functions: it can focus light for narrow FOV imaging and also create blurred spots for wide FOV detection using the same optical components. The MEMS micro-mirror array serves multiple purposes including light redirection, focus control, and FOV adjustment, reducing the need for separate mechanical systems for each function.
2Adaptability or versatility
If lenses are moved axially to adjust FOV, then the magnification and FOV can be varied, but the ease of operation decreases due to non-linear movement relationships
Solution Approach 1:
The patent replaces axial lens movement with electronic control of MEMS micro-mirror tilt angles. The mirrors can be positioned precisely through electrical signals, providing a linear and easily controllable method to adjust the field-of-view and magnification without dealing with non-linear mechanical relationships.
3Device complexity
If a common fixed FOV is used for both passive and active sensing, then the system is simpler, but the adaptability to different engagement scenarios is limited
Solution Approach 1:
The fixed optical system is designed to serve both passive imaging and active laser detection functions. By using the same optical path and components for both modes, the system maintains simplicity while the MEMS micro-mirror array provides the adaptability to switch between narrow and wide FOV configurations as needed for different engagement scenarios.
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 flexible and efficient collection and focusing of light across multiple FOV, maintaining phase coherence and allowing simultaneous passive and active imaging without interrupting visibility, with the ability to switch between modes and adjust focus for different engagement scenarios.
Implementation Method 1
A secondary mirror includes a micro-electro-mechanical system (MEMS) micro-mirror array (MMA) that can tip and tilt in two degrees of freedom (2 DOF) to (I) reflect light from the first ring within a first FOV that is focused at an imaging plane coincident with an imaging detector
Data Source
AI summary
A multiple FOV optical sensor includes a primary mirror having first and second rings of differing curvature to collect light from an object within different FOV. A secondary mirror includes a MEMS MMA in which the mirrors tip and tilt in 2 DOF or add piston in 3 DOF to (I) reflect light from the first ring within the first FOV that is focused at an imaging plane coincident with an imaging detector to form a focused image of the object at the imaging detector or (II) reflect light from the second ring within the second FOV onto the imaging detector (either focused to form a focused image or defocused to form a blurred spot). The MEMS MMA may be configured to alternate between (I) and (II) or to perform both (I) and (II) at the same time with the different FOV either overlapped or spatially separated on the detector. The sensor may be configured as an all-passive sensor, a dual-mode sensor or a hybrid of the two.