MEMS Scanner Mirror Angle Detection via Electromagnetic Substitution
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Solution Overview
Problem
Conventional MEMS scanners face challenges in integrating components for detecting the rotational angle of a mirror due to complexity in layering electric wires, increased power consumption, and reduced durability of springs, particularly in multi-layered structures.
Innovation Solution
A MEMS scanner design featuring a mirror rotatable about one or two axes, with a gimbal, spring, and substrate connected via combs to detect rotational angles by measuring capacitance values, allowing for adjustable comb thickness, length, and spacing to enhance reliability and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a strain gauge is mounted on an elastic body or spring to detect the rotational angle of the mirror, then the rotational angle can be detected, but the structure becomes complicated due to multi-layered electric wires and the integration degree is lowered
Solution Approach 1:
The patent replaces the mechanical strain gauge system with an electromagnetic detection system. A coil is mounted on the elastic body instead of a strain gauge, and rotational angle is detected by measuring changes in magnetic flux or electromagnetic induction, thereby eliminating the need for complex multi-layered electric wire structures while maintaining detection capability
Solution Approach 2:
The elastic body serves multiple functions: it provides mechanical support for the mirror, enables rotational motion, and simultaneously acts as a mounting structure for the coil that facilitates angle detection. This multi-functionality reduces the need for separate detection components and simplifies the overall structure
2Ease of operation
If a strain gauge with multi-layered electric wires is used for mirror rotation and electrical connection, then electrical connection is achieved, but the load on the spring is increased
Solution Approach 1:
The patent replaces the mechanical multi-layered wire structure with an electromagnetic field-based detection system. The coil generates or detects electromagnetic fields through the elastic body, eliminating the need for multiple physical wire layers and reducing the mechanical load on the spring while maintaining electrical connection functionality
3Measurement precision
If a strain gauge structure is used for mirror rotation detection, then rotational angle detection is achieved, but power consumption is increased and durability of the spring is deteriorated
Solution Approach 1:
The patent replaces the strain gauge with a coil-based electromagnetic detection system that requires minimal mechanical load on the spring. The coil detects rotational angle through electromagnetic induction or magnetic flux changes, significantly reducing mechanical stress on the spring and improving its durability while maintaining detection precision
Solution Approach 2:
The patent changes the detection parameter from mechanical strain (in strain gauges) to electromagnetic field parameters (magnetic flux or induced voltage). This parameter change allows for non-contact or minimal-contact detection, reducing mechanical load and improving spring reliability
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 design enables efficient detection of rotational angles with reduced power consumption and improved durability by simplifying component integration and reducing load on springs, while allowing for easy adjustment of component positions and numbers based on mirror shape and direction.
Implementation Method 1
a coil disposed on the gimbal so as to adjust the rotational angle of the mirror by generating electromagnetic force by interaction with a magnetic field, which is first formed therearound, when current flows therethrough
Implementation Method 2
The rotational angle of the mirror may be detected by measuring a capacitance value corresponding to the distance between the first and second combs, which varies with the rotation of the mirror
Data Source
AI summary
A MEMS scanner is disclosed. The MEMS scanner includes a mirror rotatable about at least one rotational axis, a gimbal disposed outside the mirror, a spring connected to the gimbal on the same line as the rotational axis of the mirror, a substrate spaced apart from an outer surface of the gimbal and connected to the gimbal via the spring, a coil disposed on the gimbal so as to adjust a rotational angle of the mirror by generating electromagnetic force by interaction with a magnetic field, which is first formed therearound, when current flows therethrough, and a plurality of combs formed between the substrate and at least one of the spring and the gimbal adjacent to the substrate so as to detect the rotational angle of the mirror.