Capacitive Acoustic Touchscreen With Conductive Bezel Shielding
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Solution Overview
Problem
Existing touch screen systems, particularly acoustic and capacitive technologies, face challenges in detecting continuous contact and are cumbersome due to the use of soldered wires and extensive shielding layers, leading to inefficiencies and increased costs in manufacturing.
Innovation Solution
A touch screen system incorporating a transparent substrate with conductive traces, acoustic sensors, and capacitive sensors connected via flexible printed circuits, along with a compressible gasket and a conductive bezel for electromagnetic shielding, allowing for effective hold-and-release sensing and position detection without the need for soldered connections or additional shielding layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soldered wires are used to interconnect capacitors in series, then capacitive sensing for hold-and-release detection is achieved, but manufacturing time increases and system reliability decreases
Solution Approach 1:
The patent replaces the mechanical soldering process with a printed conductive trace system. Capacitors are interconnected through conductive traces deposited on the substrate using printing or deposition techniques, eliminating the need for manual soldering while maintaining electrical connectivity for capacitive sensing.
Solution Approach 2:
The patent changes the manufacturing parameter from manual soldering to automated printing/deposition. This parameter change reduces manufacturing time and variability while improving consistency of capacitor interconnections for capacitive sensing operations.
2Object-affected harmful factors
If multiple conductive and insulating layers are deposited to shield against electromagnetic interference, then noise shielding is improved, but material consumption increases and manufacturing cost rises
Solution Approach 1:
The patent combines the shielding function with existing structural layers. The conductive traces that serve as capacitor interconnections also provide electromagnetic shielding, eliminating the need for separate shielding layers and reducing material consumption.
Solution Approach 2:
The conductive traces perform multiple functions: they interconnect capacitors electrically and simultaneously provide electromagnetic interference shielding. This multi-functionality reduces the total number of layers and material usage while maintaining shielding effectiveness.
3Reliability
If dedicated connectors are used to link acoustic and capacitive sensing components, then signal transmission is ensured, but device size increases and compactness is reduced
Solution Approach 1:
The patent merges the connection system for acoustic and capacitive sensors into a single integrated connector. The conductive traces on the substrate provide common electrical pathways for both sensor types, eliminating the need for separate dedicated connectors and reducing overall device volume.
Solution Approach 2:
The connector system is designed to handle both acoustic sensor signals and capacitive sensor signals through shared conductive pathways. This universal connection approach reduces the number of connectors needed while maintaining reliable signal transmission for all sensing functions.
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 design enhances the accuracy and reliability of touch screen systems by simplifying manufacturing, reducing bulk, and improving the detection of continuous contact, making it suitable for compact electronic devices.
Implementation Method 1
acoustic sensors that receive an acoustic wave generated by the contact and convert the acoustic wave to an electronic signal
Implementation Method 2
When a user touches a surface of the screen substrate with an object such as a finger, the electrodes to move towards one another, thereby reducing the gap between the electrodes and causing a capacitance variation
Data Source
AI summary
A simplified touch screen system that can sense when an object is held in continuous direct or indirect contact with a transparent substrate of the touch screen system as well as determine a location (e.g., X, Y coordinates) of the object in relation to the transparent substrate. The touch screen system employs capacitance technology to sense whether the object is held in contact with the transparent substrate and acoustic sensing technology to determine a position of the object that is contacting the transparent substrate. The touch screen system requires a reduced number of shielding and isolation layers to be deposited upon the transparent substrate, partially because the touch screen system utilizes a bezel associated with an underlying display to provide shielding against electromagnetic radiation emitted by the display.