Capacitive Force Sensor for Touch Screen Intent Recognition
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Solution Overview
Problem
Current touch screen technology cannot adequately determine the amount of force exerted by a user without complex mechanical systems, which can lead to unintended activation of software applications due to accidental touches.
Innovation Solution
A sensor system combining a touch screen that detects X, Y coordinates with a force sensor made of compressible elastomeric, piezoresistive, piezoelectric, or electro-mechanical capacitive materials, extending around the perimeter of the touch screen to measure and transmit force data to a controller, allowing differentiation between intended and unintended contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current touch screen technology is used to detect user input, then the device can detect X, Y coordinate location data, but it cannot adequately determine the amount of force exerted by the user
Solution Approach 1:
The patent replaces complex mechanical force sensing systems with a capacitive force sensor that uses electrical field principles. The sensor detects force through changes in capacitance caused by the deformation of a flexible membrane when pressure is applied, eliminating the need for complicated mechanical linkages while achieving accurate force measurement.
Solution Approach 2:
The patent utilizes the change in electrical capacitance parameter in response to mechanical deformation. When force is applied to the touch screen, the flexible membrane deforms, which changes the capacitance of the sensor element. This parameter change is detected and converted into force data, providing a simple yet effective force measurement mechanism.
2Reliability
If force sensing capability is added to the touch screen, then user intent recognition is enhanced, but the device structure becomes more complex
Solution Approach 1:
The patent merges the force sensing functionality with the existing touch screen structure. The capacitive force sensor is integrated into the touch screen assembly, combining the touch detection and force detection functions into a unified system. This integration enhances user intent recognition while minimizing the increase in overall device complexity.
3Reliability
If a force sensor is integrated with the touch screen, then accidental touches can be differentiated from intentional contacts, but the manufacturing process becomes more complex
Solution Approach 1:
The patent employs a flexible membrane structure as part of the capacitive force sensor. This thin film component is integral to both the touch screen and force sensing functions, allowing for simplified manufacturing processes. The flexible membrane can be manufactured using standard touch screen fabrication techniques, reducing the complexity of integration.
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
Enhances user intent recognition by providing accurate force data to the controller, reducing accidental activations and enabling more precise control of software applications, while also providing a natural feeling with haptic feedback.
Implementation Method 1
The force sensor may be formed of a compressible elastomeric material
Implementation Method 2
The force sensor may be formed of one of the following materials: a piezoresistive material
Implementation Method 3
The force sensor may be formed of one of the following materials: a piezoelectric material
Implementation Method 4
The force sensor may be formed of one of the following materials: an electro-mechanical capacitive material
Data Source
AI summary
A sensor system includes a touch screen and a force sensor. The touch screen has a first and second surface and detects a first surface touch and converts it to data indicative of an X, Y coordinate position upon the touch screen first surface. The force sensor contacts the touch screen second surface and substantially extends around the perimeter of the touch screen second surface. The force sensor measures the force exerted by the first surface touch in the form of force data.