Stylus Strain Sensor and Haptic Motor for Force Sensing
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Solution Overview
Problem
Current handheld input devices struggle to accurately sense subtle user manipulations, limiting their ability to simulate a realistic drawing experience due to their inability to detect nuanced forces and orientations effectively.
Innovation Solution
A handheld input apparatus equipped with a strain sensor to determine load forces and haptic motor to control haptic interactions, allowing for the simulation of different pen types, brush types, and textures by adjusting frictional forces based on detected forces and orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If basic force sensing is used in handheld input devices, then the device can detect user input, but it cannot accurately sense subtle user manipulations
Solution Approach 1:
The force sensing capability is divided into multiple independent strain sensors positioned at different locations within the stylus body. Each sensor detects force in specific directions (normal force, lateral forces), allowing the system to capture subtle manipulations through distributed measurement points rather than a single complex sensor
Solution Approach 2:
The patent transitions from basic one-dimensional force detection to three-dimensional force sensing by incorporating strain sensors that measure forces in multiple directions (normal to the surface, lateral forces parallel to the surface). This dimensional expansion enables accurate sensing of subtle manipulations including pressure, tilt, and friction forces
2Measurement precision
If multiple sensors are added to detect nuanced forces and orientations, then sensing accuracy improves, but device complexity increases
Solution Approach 1:
The strain sensor system serves multiple functions simultaneously: detecting normal force (pressure), lateral forces (friction), and orientation (tilt angle). This multi-functionality allows accurate orientation detection without requiring separate dedicated sensors for each measurement type, thereby managing device complexity while improving measurement precision
Solution Approach 2:
The patent replaces complex mechanical orientation sensing mechanisms with strain-based detection. The strain sensors mounted on the stylus body detect orientation changes through mechanical strain caused by tilting, substituting traditional mechanical gyroscopes or accelerometers with a simpler strain measurement approach
3Reliability
If haptic feedback is added to simulate textures, then drawing realism improves, but device complexity increases
Solution Approach 1:
The system implements closed-loop haptic feedback where strain sensors detect user input forces and orientations, the computing device processes this information to determine desired haptic responses, and haptic actuators deliver appropriate tactile feedback. This feedback loop creates realistic drawing experiences by simulating texture resistance and friction forces
Solution Approach 2:
The haptic system dynamically changes physical parameters including vibration frequency, amplitude, and friction force magnitude based on detected user input. By varying these parameters in response to drawing actions, the system simulates different textures and surfaces without requiring physically complex mechanical structures
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
Enables precise control over digital ink characteristics such as line width, shading, and texture, providing a more realistic drawing experience by accurately interpreting user inputs and simulating various haptic interactions.
Implementation Method 1
a strain sensor for determining different load forces on a tip of the apparatus
Implementation Method 2
A handheld input apparatus equipped with a strain sensor to determine load forces and haptic motor to control haptic interactions, allowing for the simulation of different pen types, brush types, and textures by adjusting frictional forces
Data Source
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AI summary
Techniques for haptics for a handheld input apparatus (stylus) are described. Generally, a handheld input apparatus can be used to provide input to various types of devices. According to various embodiments, a described handheld input apparatus includes a haptic motor for generating different haptic interactions between a tip of the apparatus and an input surface. According to various embodiments, a described handheld input apparatus includes strain sensors for determining different load forces on a tip of the apparatus. In at least some embodiments, a haptic mode for the haptic motor is determined based on load force detected by the strain sensors.