Stylus Nib Pressure Sensing via Pneumatic Bladder
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Solution Overview
Problem
Existing styli with integral force sensors face challenges in accurately sensing nib pressure across varying altitudes and ambient conditions without the need for manual or automatic calibration, and often require costly sensor technologies.
Innovation Solution
A stylus design incorporating a first pressure sensor to sense air pressure corresponding to nib force and a second sensor for ambient air pressure, with a control circuit determining gauge pressure, and optionally including a temperature sensor for temperature compensation, utilizing a fluid-filled bladder and a mechanical stop to provide reliable and self-calibrating force sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical, piezoelectric, or resistive force sensors are used in the stylus, then force sensing capability is provided, but the device complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical force sensing systems (optical, piezoelectric, or resistive sensors) with a simpler pneumatic system using a fluid-filled bladder and a pressure sensor. The mechanical compression of the bladder converts force applied to the stylus tip into pressure changes that can be measured by a standard pressure sensor, thereby simplifying the overall system while maintaining force sensing capability.
Solution Approach 2:
The invention employs a pneumatic sensing mechanism where a fluid-filled bladder transmits mechanical force as pressure changes to a pressure sensor. This pneumatic approach allows the use of inexpensive, miniaturized pressure sensors instead of complex force sensors, reducing device complexity and cost while providing reliable force measurement.
2Measurement precision
If force sensors are calibrated manually or automatically, then measurement precision is improved, but the ease of operation and device complexity increase
Solution Approach 1:
The patent implements a self-calibrating system where the stylus automatically compensates for ambient pressure variations and temperature effects without requiring user intervention. The control circuit continuously adjusts the force measurement based on sensor readings from ambient pressure and temperature sensors, eliminating the need for manual calibration while maintaining high measurement precision across different operating conditions.
3Adaptability or versatility
If the stylus operates at varying altitudes, then adaptability is improved, but measurement precision deteriorates due to ambient pressure changes
Solution Approach 1:
The invention employs feedback control by continuously monitoring ambient pressure and temperature through dedicated sensors and using this information to compensate for their effects on force measurement. The control circuit adjusts the pressure sensor readings in real-time based on ambient conditions, maintaining measurement precision across varying altitudes and environmental conditions.
Solution Approach 2:
The patent compensates for ambient pressure and temperature effects by dynamically adjusting the force measurement parameters. The control circuit uses sensor data to calculate compensation factors that correct the raw force measurements, allowing the stylus to maintain accurate force sensing performance despite changes in altitude and environmental conditions.
4Reliability
If expensive sensor technologies are used, then force sensing reliability is improved, but manufacturing cost increases
Solution Approach 1:
The invention replaces expensive, complex force sensors with inexpensive, miniaturized pressure sensors that can be easily manufactured. The pneumatic bladder system uses standard components that are cost-effective to produce, significantly reducing manufacturing costs while maintaining reliable force sensing capability through the simplicity and robustness of the pneumatic mechanism.
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 allows for accurate and cost-effective force sensing that is invariant to temperature and ambient conditions, enabling reliable operation at different altitudes without separate calibration, using miniature air pressure sensors at a reduced cost.
Implementation Method 1
A first pressure sensor is configured to sense air pressure that corresponds to force being supplied to the stylus nib
Implementation Method 2
A fluid-filled bladder is configured to sense a pressure that corresponds to a force being applied to the stylus nib
Implementation Method 3
A mechanical stop can serve to prevent the fluid-filled bladder from deforming beyond a given amount of deformation
Implementation Method 4
By one approach a temperature sensor can also operably couple to the control circuit and provide temperature information
Data Source
AI summary
A stylus has a stylus barrel and a stylus nib that can move with respect to the stylus barrel. A first pressure sensor is configured to sense air pressure that corresponds to force being supplied to the stylus nib and a second pressure sensor serves to sense ambient air pressure. A control circuit operably couples to both pressure sensors and determines a gauge pressure value as corresponds to force being applied to the stylus nib. By one approach a temperature sensor can also operably couple to the control circuit and provide temperature information that the control circuit can utilize when determining the aforementioned gauge pressure value.