Force and Location Sensitive Display with Deformable Members
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Solution Overview
Problem
Existing touch screen technologies do not provide pressure or force information and are unable to track multiple points of contact simultaneously, limiting their functionality in providing robust command and control signals for devices like tablet computers and mobile phones.
Innovation Solution
A display unit comprising two transparent substrates with conductive traces and deformable members between them, which detect capacitance changes to sense both location and force of touch, allowing for simultaneous force and location detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If conventional touch screen technologies (resistive, capacitive, infrared, surface acoustic wave) are used, then the display can detect touch location, but it cannot provide pressure or force information
Solution Approach 1:
The patent combines location detection and force detection functions into a single integrated display structure. Multiple conductive trace sets (first set in first direction, second set in second direction) are embedded within the same transparent substrate, allowing simultaneous measurement of both touch location and applied force through a unified sensor architecture rather than separate systems.
Solution Approach 2:
The conductive trace network serves multiple functions: it detects touch location through capacitance changes at contact points and simultaneously measures applied force through the interaction between perpendicular trace sets. The deformable member integrated into the substrate enables the same structure to respond to both positional and forceful aspects of user input.
2Measurement precision
If conventional touch screen technologies are used, then the display can detect single point touch, but it cannot track multiple points of contact simultaneously
Solution Approach 1:
The conductive traces are arranged in multiple segmented sets oriented in different directions (first set in first direction, second set in second direction). This segmentation allows the system to independently identify and track multiple distinct contact points across the display surface, as each trace set can detect contacts along its respective orientation, enabling simultaneous multi-point touch detection.
3Loss of information
If deformable members are added to detect force, then force information can be obtained, but visual aspects may be degraded
Solution Approach 1:
The deformable member is integrated within the transparent substrate structure, allowing it to deform in response to applied force while remaining optically transparent. This thin-film integration ensures that the force-sensing element does not obstruct or degrade the visual display quality, as the substrate material itself serves as both the structural support and the optical window.
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 a display unit capable of detecting both the location and force of touch, providing a more robust input dimension for electronic devices and allowing multiple points of contact to be tracked simultaneously.
Implementation Method 1
The first set of conductive traces, in combination with the conductive traces of the second transparent element, are configured to provide a capacitance signal representing where a user touches the display element. The second set of conductive traces, in combination with the conductive traces of the second transparent element, are configured to provide a capacitance signal representing the amount of force applied to the display element.
Implementation Method 2
A plurality of deformable members (e.g., rubber beads) juxtaposed between the first and second transparent substrates
Data Source
AI summary
A unit to provide both force and location detection includes a first transparent substrate (having first and second sets of conductive traces oriented in a first direction), a second transparent substrate (having a third set of conductive traces oriented in a second direction) and a plurality of deformable members (e.g., rubber beads) arranged between the first and second transparent substrates. The first set of conductive traces, in combination with the conductive traces of the second transparent element, provide a capacitance signal representing where a user touches the display element. The second set of conductive traces, in combination with the conductive traces of the second transparent element, provide a capacitance signal representing the amount of force applied to the display element. When used with a display element (e.g., a LCD or CRT), an input-output unit capable of both location sensing and force sensing operations is provided.