Electronic Stylus Multi-Axis Force Sensor
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Solution Overview
Problem
Existing electronic stylus technologies face limitations in accurately approximating the force magnitude applied by the stylus tip normal to an inking surface, especially when the long axis of the stylus is not orthogonal to the surface, leading to inaccuracies in rendering ink, particularly in artistic applications where angles are less than 45°.
Innovation Solution
The electronic stylus device incorporates a nutation collar and deflection sensors, including a magnet and Hall Effect sensor, to measure both axial and lateral deflections, allowing for precise computation of the force applied to the inking surface by detecting lateral and axial forces, which improves the accuracy of force approximation across various usage states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only long axis force measurement is used, then the device complexity is reduced, but the measurement precision of force applied to the inking surface deteriorates
Solution Approach 1:
The patent transitions from one-dimensional (long axis only) force measurement to three-dimensional force measurement by adding lateral force sensors. The lateral force sensor measures forces perpendicular to the long axis, enabling the system to capture force components in multiple dimensions. This dimensional expansion allows accurate calculation of the normal force component applied to the inking surface regardless of stylus orientation angle.
Solution Approach 2:
The patent introduces a nutation collar as an intermediary mechanical element that facilitates lateral movement of the stylus tip element relative to the long axis. This nutation mechanism acts as a mediator that converts complex multi-directional forces into measurable lateral deflections, enabling the lateral force sensor to accurately capture force components that would otherwise be difficult to measure directly.
2Measurement precision
If multi-axis force sensors are added, then the measurement precision of force applied to the inking surface is improved, but the device complexity increases
Solution Approach 1:
The patent segments the force measurement function into two independent sensor components: a long axis force sensor for measuring axial forces and a lateral force sensor for measuring perpendicular forces. This segmentation allows each sensor to be optimized for its specific measurement direction, simplifying the overall system architecture while achieving comprehensive three-dimensional force measurement capability.
Solution Approach 2:
The nutation collar serves multiple functions: it enables lateral movement of the stylus tip element, provides a mechanical linkage for force transmission to the lateral force sensor, and allows the system to maintain accuracy across various stylus orientation angles. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in device complexity.
3Adaptability or versatility
If the stylus is used at non-orthogonal angles, then the adaptability of the device is improved, but the measurement precision of normal force deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the lateral force sensor continuously monitors lateral force components, and this information is fed back to the processing system. The processing system uses both long axis force and lateral force measurements to dynamically calculate the accurate normal force component applied to the inking surface, compensating for variations in stylus orientation angle and maintaining measurement precision across different usage angles.
Solution Approach 2:
The patent changes the measurement parameters from solely axial force to a combination of axial force and lateral force. By measuring both force components and using trigonometric relationships, the system can calculate the normal force component (Fn) applied to the inking surface regardless of the stylus orientation angle, thereby maintaining measurement precision across a wide range of adaptable usage angles.
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 solution enables more accurate rendering of ink by accurately computing the force applied to the inking surface, even at non-orthogonal angles, enhancing the precision of artistic strokes and shading by accounting for frictional forces and variations in tilt and lateral forces.
Implementation Method 1
a Hall Effect sensor positioned proximate to the magnet on the long center axis, the Hall Effect sensor being configured to detect lateral and axial deflections of the magnet relative to the Hall Effect sensor
Data Source
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AI summary
An electronic stylus device includes a stylus tip element having a stylus tip end and an opposing end. The stylus tip element is positioned at an end of the electronic stylus device and aligned along the long center axis of the electronic stylus device. A nutation collar is positioned about the stylus tip element and the long center axis. The nutation collar provides one or more bearing surfaces around the stylus tip element between the stylus tip end and the opposing end of the stylus tip element. The one or more bearing surfaces permit the stylus tip element to nutate within the nutation collar. A deflection sensor is positioned proximate to the opposing end of the stylus tip element on the long center axis and detects lateral deflection of the opposing end of the stylus tip element relative to the long center axis of the electronic stylus device.