Variable Width Drive Coil for MEMS Scanner Resistance
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Solution Overview
Problem
Scanned laser displays with MEMS-based electromagnetically driven actuators face challenges in reducing power consumption due to coil resistance, which increases with fewer turns in the actuator coil, leading to higher drive current requirements and inefficiency from joule heating.
Innovation Solution
The implementation of a drive coil with variable width windings, transitioning between narrower and wider sections to optimize electrical and mechanical characteristics, reducing overall resistance and power consumption while maintaining torque efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the number of turns in the actuator coil is reduced, then the coil resistance is reduced, but the drive current requirement increases
Solution Approach 1:
The coil windings have variable cross-sectional area along their length, with different sections having different widths. This local variation in geometry allows different parts of the coil to have different resistance characteristics, enabling the coil to achieve lower overall resistance without reducing the number of turns, thus resolving the contradiction between resistance reduction and maintaining torque production.
2Force
If the drive current is increased, then the torque production is maintained, but the joule heating increases
Solution Approach 1:
The patent changes the geometric parameters of the coil windings by varying the cross-sectional area (width) along the length of the windings. This parameter change allows the coil to optimize its electrical resistance while maintaining the mechanical properties needed for torque production, thereby reducing joule heating without compromising force output.
3Loss of energy
If the cross section of the conductor is increased, then the coil resistance is reduced, but the coil width becomes non-uniform
Solution Approach 1:
The coil design transitions from a static, uniform cross-section to a dynamic, variable cross-section where the width changes along the length of the windings. This dynamic geometric configuration allows the coil to achieve lower resistance in critical areas while maintaining overall structural integrity and functional performance.
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 approach minimizes power consumption and enhances efficiency by reducing coil resistance and balancing mass distribution, thereby improving the performance of the scanning platform without compromising torque production.
Implementation Method 1
a current carrying conductor in a coil arrangement interact with the magnetic field of a permanent magnet or electromagnet to generate torque that moves the scan platform
Implementation Method 2
The resistance of the current carrying conductor may significantly affect the power consumption of the actuator... Increasing the drive current also produces increased joule heating which decreases the efficiency of the actuator
Data Source
AI summary
Briefly, in accordance with one or more embodiments, a scanner for a scanned beam display may comprise a scanning platform having a mirror disposed thereon to reflect a beam of light impinging on the mirror, a drive coil disposed on the scanning platform to scan the reflected beam of light in response to a drive current applied to the drive coil. The drive coil has coil winding segments having a narrower width in one or more regions of the drive coil, and has coil winding segments having a greater width in one or more other regions of the drive coil to provide a the drive coil with a reduced electrical resistance.