AROD Magnet Haptic Engine for Touch Bar Lorentz Force
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Solution Overview
Problem
Conventional haptic engine modules with extreme aspect ratios, such as those in touch bars, suffer from reduced magnetic flux and Lorentz force due to self-demagnetization and inefficient magnetic field distribution, limiting their effectiveness in providing haptic feedback.
Innovation Solution
The use of Adjacent Radially Opposed Direction (AROD) magnets, where two adjacent magnets with opposite polarizations are positioned perpendicular to the vibration direction, and coils are placed above and below these magnets, allowing for increased magnetic flux and improved magnet manufacturability, enhancing the Lorentz force generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the coil and magnet are extended in the long direction to fit extreme aspect ratio housing, then the device can be embedded in compact spaces, but the magnetic flux contribution to Lorentz force is reduced
Solution Approach 1:
The single magnet is divided into multiple magnet segments (e.g., three segments) arranged along the long direction. Each segment generates magnetic flux that contributes to the Lorentz force, and the segmented configuration prevents self-demagnetization while maintaining compact footprint in the housing.
Solution Approach 2:
The magnetic flux projection is optimized by arranging magnet segments and coils in a three-dimensional configuration where magnetic flux is projected perpendicular to both the vibration direction and polarization direction, maximizing the Lorentz force within the constrained housing volume.
2Ease of manufacture
If conventional single magnet design is used in extreme aspect ratio housing, then manufacturing is simpler, but magnetic field distribution is inefficient and self-demagnetization occurs
Solution Approach 1:
The magnet is segmented into multiple pieces with opposite polarizations arranged adjacently. This segmentation prevents self-demagnetization by eliminating the demagnetizing field that occurs in long single magnets, while the segments can be manufactured using standard processes.
Solution Approach 2:
Multiple magnet segments with opposite polarizations are combined in an adjacent radially opposed direction (AROD) configuration. The segments work together to generate enhanced magnetic flux that projects perpendicular to the vibration direction, improving magnetic field stability and preventing demagnetization.
3Shape
If magnets are arranged with extreme aspect ratio, then they fit the housing dimensions, but demagnetization temperature is reduced
Solution Approach 1:
By dividing the magnet into segments with aspect ratios suitable for manufacturing and thermal stability, the demagnetization temperature is improved. Each segment has optimized dimensions that prevent thermal demagnetization while fitting within the extreme aspect ratio housing when arranged in the segmented configuration.
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 configuration increases the Lorentz force and demagnetization temperature, providing more effective haptic feedback and improved manufacturability compared to traditional designs, with a 10% increase in magnetic flux and better thermal stability.
Implementation Method 1
a proof-mass disposed in the housing proximate to the first and second coils, the proof-mass configured to move within the housing in a second direction perpendicular to the first direction in response to a Lorentz force generated by a magnetic field caused by excitation current flowing in opposite directions in the first and second coils
Implementation Method 2
a first magnet disposed on or in the proof-mass and having a first magnetic polarization, the first magnet arranged relative to the first and second coils such that a first magnetic flux of the first magnet is projected onto the first and second coils
Data Source
AI summary
Embodiments are disclosed for a haptic engine module that includes AROD magnets. The AROD magnets comprise two adjacent magnets with opposite polarization and adjacent coils above and/or below the magnets. The magnets and coils are adjacent in along direction, which is the direction that is perpendicular to the vibration direction (the direction of the Lorentz force) and to the polarization direction (the direction of magnetic flux). When in operation, excitation current flows in the two coils in opposite directions. The haptic engine module can be embedded in an electronic device with an extreme aspect ratio (e.g., a touch bar of a notebook computer) to provide haptic force (e.g., vibration, click) that can be felt by a user holding or touching the electronic device.