Variable Resistance Zones and Mini-stops for Accurate Position Sensing
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Solution Overview
Problem
Existing touch sensors for electronic devices face issues with inconsistent signal generation due to varying user force and speed, leading to inaccurate position reporting, especially in miniature devices like cell phones and PDAs, where hard stops and variable joysticks exacerbate these problems.
Innovation Solution
A system with multiple variable resistors arranged in a substrate and an actuator that transfers pressure across these resistors, coupled with a converter to map pressure and location, allowing for accurate tracking of finger pressure and movement, effectively functioning as a scroll wheel or navigation device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If hard stops are used to limit motion range in miniature devices, then device size is reduced, but position sensing accuracy deteriorates due to compliance and inertia effects
Solution Approach 1:
The hard stop is segmented into multiple mini-stops distributed along the travel path. This segmentation allows the sensing system to detect position through multiple discrete contact points rather than relying on a single hard stop, thereby maintaining position accuracy while limiting motion range in miniature devices.
Solution Approach 2:
Mini-stops serve as intermediary elements between the movable component and the sensing system. These mini-stops provide defined contact points that mediate the interaction, allowing accurate position detection through electrical contact while maintaining compact device dimensions.
2Adaptability or versatility
If variable device joysticks are incorporated into miniature devices, then device functionality is enhanced, but position reporting consistency deteriorates due to compliance and inertia
Solution Approach 1:
The variable joystick mechanism is divided into discrete segments with individual mini-stops at key positions. This segmentation creates defined electrical contact points that provide consistent position reporting regardless of compliance or inertia effects during movement.
Solution Approach 2:
The continuous mechanical position sensing is replaced with discrete electrical contact sensing through mini-stops. This substitution eliminates the problems of compliance and inertia affecting position detection, as the electrical contact provides direct and consistent position information.
3Productivity
If touch sensors are made more sensitive to user force, then input responsiveness is improved, but position accuracy deteriorates due to non-uniform resistance variations
Solution Approach 1:
The continuous touch sensor surface is segmented into multiple discrete sensing zones with associated mini-stops. This segmentation creates distinct resistance change patterns for each zone, allowing the system to determine position based on which zone is activated rather than relying on continuous resistance measurements that are sensitive to force variations.
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 precise tracking of pressure and location, providing consistent and accurate navigation and haptic feedback, improving user experience by reducing counterintuitive position values and enhancing device performance in constrained form factors.
Implementation Method 1
multiple pressure-sensitive variable resistors... Each of the resistive members is deformable to thereby contact a corresponding one of the multiple conductive elements at a location on the conductive element, thereby generating a voltage differential at the resistive member corresponding to the location on the corresponding conductive element
Data Source
AI summary
The present invention is directed to variable resistance zones for sensing input to an electronic device, as well as ministops for controlling deformation of the input components to ensure the accuracy of the inputs sensed. In one embodiment, a system in accordance with the present invention includes multiple variable resistors, an actuator, and a converter. The actuator overlies the multiple pressure-sensitive variable resistors and is configured to generate a pressure at a contact location on the multiple variable resistors. The converter is coupled to the multiple variable resistors and is programmed to map a pressure at the contact location to a pressure, location, or both along the surface of the actuator.