Dual-Pronged Capacitive Sensor Pattern for Signal Integrity
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Solution Overview
Problem
Current capacitive touch-sensor arrays face challenges in accurately detecting multiple touches and maintaining signal integrity due to limitations in sensor element design and manufacturing yield, particularly in achieving high signal-to-noise ratios and minimizing visibility of bridges in the sensor array.
Innovation Solution
The implementation of a dual-pronged capacitive sensor array pattern with redundant bridges and connecting subtraces, which enhances signal disparity characteristics and manufacturing yield while reducing visibility, and includes a design where each unit cell has two bridges for improved redundancy and optical uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional capacitive sensor array pattern is used, then the manufacturing process is simpler, but the signal-to-noise ratio is lower and manufacturing yield is reduced
Solution Approach 1:
The sensor element is divided into multiple segments including first and second prongs, bridges, and connecting subtraces. This segmentation allows each component to be optimized independently for signal integrity while maintaining manufacturability. The bridges connect the prongs in a configuration that enhances signal-to-noise ratio without requiring complete redesign of the entire sensor element.
Solution Approach 2:
Different regions of the sensor element are designed with different properties: the prongs are optimized for capacitive coupling and signal generation, the bridges are designed with specific geometries to minimize visibility and maximize electrical connection, and the connecting subtraces are routed to optimize signal paths. This local optimization allows improvement of signal-to-noise ratio in critical areas without uniformly increasing complexity throughout the entire array.
2Ease of manufacture
If bridges are made more visible or prominent in the sensor array, then manufacturing and alignment may be easier, but optical uniformity and aesthetic appearance deteriorate
Solution Approach 1:
The bridges are designed with asymmetric geometries where the width, length, and positioning are optimized to minimize their visual impact while maintaining electrical functionality. The bridges connect the prongs in non-uniform patterns that are less visually apparent, allowing the sensor array to maintain optical uniformity across the display surface while still providing robust electrical connections.
Solution Approach 2:
The bridge design incorporates dimensional variations in the z-axis (thickness) and angular orientations that reduce their visual profile. By adjusting the bridges to be thinner or positioned at angles that minimize light reflection and visibility, the design maintains ease of manufacturing through standard deposition processes while achieving superior optical uniformity in the finished product.
3Productivity
If redundant bridges and connecting subtraces are added to each unit cell, then manufacturing yield and signal disparity characteristics improve, but the device complexity increases
Solution Approach 1:
Redundant bridges are incorporated into the sensor element design to provide backup signal paths before manufacturing defects or signal degradation can occur. If one bridge or connecting subtrace fails or experiences signal loss, the redundant paths ensure continued functionality, thereby improving manufacturing yield and reliability without requiring complex post-manufacturing corrections or adjustments.
Solution Approach 2:
The design optimizes the parameters of the bridges and connecting subtraces such as width, length, material composition, and routing paths to achieve the desired level of redundancy with minimal increase in complexity. By carefully tuning these parameters, the design achieves improved manufacturing yield and signal disparity characteristics while keeping the additional structural elements within acceptable complexity limits for standard manufacturing processes.
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 improves the signal-to-noise ratio and manufacturing yield, enabling more accurate detection of multiple touches and maintaining optical uniformity, thus enhancing the overall performance and reliability of capacitive touch-sensor arrays.
Implementation Method 1
capacitive sensor arrays face challenges in accurately detecting multiple touches and maintaining signal integrity
Implementation Method 2
electrically-sensitive (capacitive)
Data Source
AI summary
One embodiment of a capacitive sensor array may comprise a first plurality of sensor elements and a second sensor element capacitively coupled with each of the first plurality of sensor elements. The second sensor element may further comprise a first main trace and a second main trace, where the first main trace and the second main trace intersect each of the first plurality of sensor elements, and where each of the main traces cross at least one of a plurality of unit cells associated with the second sensor element. The second sensor element may also comprise a connecting subtrace electrically coupled to both the first main trace and the second main trace, and within each unit cell, at least one primary subtrace branching away from the first main trace or the second main trace.