Pressure-Sensitive Stylus with Pyramid Sensor for Multi-Axial Force Detection
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Solution Overview
Problem
Existing styluses are inadequate in detecting both axial and cross-axial forces applied to the writing tip, which limits their sensitivity and accuracy in tracking the transition between hovering and touch states on a sensing surface.
Innovation Solution
A pressure-sensitive stylus with an elastic element and a pyramid structure, where the elastic element is connected to the writing tip and the pyramid structure is integrated into the housing, allowing for capacitive coupling and resistivity changes to detect both the magnitude and direction of forces applied, enhancing sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional pressure sensor is used in the stylus, then axial force detection is possible, but cross-axial force detection is not achieved
Solution Approach 1:
The pressure sensor is segmented into multiple sensing elements arranged in a pyramid structure with electrodes on different surfaces. Each sensing element detects force in specific directions, collectively covering both axial and cross-axial force components through spatial segmentation of the sensing function.
Solution Approach 2:
The sensing capability is extended from one dimension (axial force only) to three dimensions by adding cross-axial force detection capability. The pyramid structure with electrodes on multiple surfaces enables detection of force vectors in multiple spatial dimensions, transforming the sensor from scalar to vector measurement.
2Ease of operation
If the writing tip is held at an angle during interaction, then natural writing posture is achieved, but accurate force detection becomes difficult
Solution Approach 1:
The sensing system is designed to be dynamic and adaptive, automatically adjusting to the stylus orientation and writing angle. The pyramid structure with multiple electrode surfaces allows the sensor to detect force components regardless of the writing tip's angular position, maintaining measurement precision across varying operational configurations.
Solution Approach 2:
The pressure sensor is designed with universal detection capability that works effectively at various writing angles. By incorporating sensing elements on multiple surfaces of the pyramid structure, the sensor can detect axial and cross-axial forces regardless of the stylus's angular orientation, making the system universally applicable to natural writing postures.
3Device complexity
If only axial force detection is implemented, then device complexity is reduced, but transition detection between hovering and touch states is inaccurate
Solution Approach 1:
The detection function is segmented across multiple electrode surfaces arranged in a pyramid structure. Each surface contributes to detecting specific force components, and the combined output from all segments enables accurate determination of state transitions between hovering and touch modes through综合分析 of multi-directional force data.
4Measurement precision
If cross-axial force detection is added to axial force detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Multiple sensing functions are merged into a single integrated pyramid structure. The electrodes on different surfaces of the pyramid are combined into one cohesive sensor assembly that simultaneously detects both axial and cross-axial forces, reducing the need for separate sensor components and simplifying the overall device architecture.
Solution Approach 2:
The pyramid structure serves multiple detection functions simultaneously. The same structural element detects both axial and cross-axial force components, making the sensor multi-functional and eliminating the need for separate sensing mechanisms for different force directions, thereby managing complexity while enhancing measurement precision.
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
The stylus effectively detects both axial and cross-axial forces, improving its ability to accurately track the writing tip's position and state, enhancing the transition detection between hovering and touch modes.
Implementation Method 1
an elastic element and a pyramid structure, where the elastic element is connected to the writing tip
Implementation Method 2
allowing for capacitive coupling and resistivity changes to detect both the magnitude and direction of forces applied
Implementation Method 3
allowing for capacitive coupling and resistivity changes to detect both the magnitude and direction of forces applied
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
A handheld device includes a housing, an elongated rod movable with respect to the housing, a pyramid structure and a circuit. The elongated rod includes a tip at a first end and a compressible element at a second end. The compressible element includes conductive material configured to press against the electrodes based on a force vector applied on the tip. The pyramid structure includes at least three walls and an electrode on each of the at least three walls and is fixed or integrated with the housing. The circuit transmit signals on the compressible element or the electrodes, detect outputs from the electrodes and provide pressure related information based on the outputs.