Capacitive Digitizer Sensor with Resilient Layer for Wet Environment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Capacitive-based digitizer systems struggle to accurately sense the position and pressure of interacting objects, especially non-conductive objects and those used in wet or underwater conditions, due to disruptions caused by water and inability to detect non-conductive materials effectively.
Innovation Solution
Integration of a resilient layer with a capacitive sensor that compresses under pressure, allowing for enhanced capacitive detection and pressure sensitivity, along with spacers or air gaps to increase proximity and detect interactions in wet conditions, enabling the sensing of both conductive and non-conductive objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional capacitive sensor is used, then it can detect conductive objects, but it cannot effectively detect non-conductive objects or operate in wet conditions
Solution Approach 1:
A resilient layer is introduced as an intermediary between the capacitive sensor and the interacting object. This layer compresses under pressure to change the air gap distance, thereby modulating the capacitive coupling between the sensor and non-conductive objects or objects in wet conditions, enabling detection where traditional sensors fail.
Solution Approach 2:
The system changes the physical parameter of the air gap distance by using a resilient layer that compresses under applied pressure. This dynamic parameter change enhances capacitive coupling strength, allowing the sensor to detect non-conductive objects and maintain operation in wet conditions while preserving measurement precision.
2Measurement precision
If the sensing surface is placed close to the interacting object, then capacitive coupling is enhanced, but the sensor cannot detect pressure variations
Solution Approach 1:
The resilient layer merges two functions: it maintains a small air gap for enhanced capacitive coupling while simultaneously providing pressure sensitivity through its compression characteristics. This combination allows the sensor to detect both position and pressure without requiring separate sensing mechanisms.
Solution Approach 2:
The air gap distance is made dynamic rather than fixed. The resilient layer allows the gap to change dynamically in response to applied pressure, enabling the sensor to extract pressure information from capacitance measurements while maintaining strong coupling for accurate position detection.
3Adaptability or versatility
If a resilient layer is added to enable pressure sensing, then pressure and position can be detected, but the device complexity increases
Solution Approach 1:
The resilient layer serves multiple functions simultaneously: it acts as a mechanical element for pressure sensing, a capacitive coupling enhancer by maintaining small air gaps, and a protective element for the sensor. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
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 solution effectively detects the position and pressure of interacting objects, including non-conductive ones, even in wet environments, by enhancing capacitive coupling and signal detection, providing accurate tracking and pressure measurement.
Implementation Method 1
a resilient layer under which the sensor layer is mounted, the sensor layer configured to detect local compressions based on pressure applied to the resilient layer
Implementation Method 2
A mutual capacitive sensor is one type of capacitive sensor for a digitizer system... Bringing a finger or conductive object close to the surface of the sensor changes the local electrostatic field and reduces the mutual capacitance between junction areas
Implementation Method 3
digitizer systems that are operated to use sensed pressure profiles to detect position of the interacting object... while a sensing surface of the digitizer sensor is wet
Data Source
AI summary
A sensor includes a sensor layer patterned with conductive elements spread across the sensor layer and a resilient layer proximate to the sensor layer. The conductive elements are electrically isolated from one another. The sensor layer is configured for capacitive based sensing and to detect local compressions based on pressure applied to the resilient layer.