Touch Sensor Conductor Routing for Bezel-Free Displays
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Solution Overview
Problem
Touchscreen devices with bezels around the edges suffer from reduced touch resolution and signal quality due to increased spacing between touch sensors and signal coupling issues when routing transparent touch sensor traces between columns or rows of sensors, limiting the display area and user experience.
Innovation Solution
Routing transparent touch sensor traces between the edge of a sensing area and sensors instead of between or outside the sensing area, allowing for improved touch resolution and signal quality while maintaining a bezel-free design, which enables image display and touch sensing anywhere within the touchscreen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If transparent touch sensor traces are routed between columns or rows of sensors, then touch sensing functionality is achieved, but signal coupling issues occur and touch resolution deteriorates
Solution Approach 1:
The patent extracts the sensor traces from the interior sensing area and relocates them to the edges of the sensing area. This separation removes the traces from the active sensing region, eliminating signal coupling interference with sensor elements while maintaining electrical connectivity, thus resolving the contradiction between achieving touch sensing functionality and avoiding signal quality degradation
Solution Approach 2:
The patent transitions the trace routing from a two-dimensional grid pattern (routing between rows and columns within the sensing area) to a one-dimensional edge-aligned pattern. By confining traces to edge regions and aligning them parallel to sensing area boundaries, the patent eliminates intersection points with sensor elements, thereby preventing signal coupling while preserving touch detection capability
2Area of stationary object
If bezels are used around the edges to hide conductors, then conductor routing is simplified, but display area is reduced and user experience deteriorates
Solution Approach 1:
The patent applies different routing strategies to different spatial regions: traces are routed along the edges of the sensing area where they can be concealed by thin bezels or frames, while the central sensing area remains free of conductors to maintain high touch resolution. This localized routing approach allows minimal bezel width while achieving both aesthetic and functional goals
Solution Approach 2:
The patent introduces edge regions as intermediary zones between the central sensing area and the outer bezel structure. These edge regions serve as conductors' pathways, allowing traces to be routed close to the sensing area boundary while remaining concealed by the bezel, thus maximizing display area without exposing complex routing
3Ease of manufacture
If spacing between touch sensors is increased to accommodate conductor routing, then conductor routing becomes easier, but touch resolution deteriorates
Solution Approach 1:
The patent segments the sensing area into a central sensing region and peripheral edge regions. The central region maintains high sensor density for optimal touch resolution, while the edge regions are designated for conductor routing. This spatial segmentation allows both high-resolution sensing and easy conductor manufacturing without requiring increased spacing between sensors in the active sensing area
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 approach enhances touch resolution and signal quality, maximizes display area, and improves user experience by eliminating the need for opaque bezels, allowing touch sensing to occur wherever images are displayed without compromising sensor performance.
Implementation Method 1
routing transparent touch sensor traces between the edge of a sensing area and sensors
Implementation Method 2
measuring, through sensor signals, a change in capacitance associated with the capacitive sensor elements to determine a presence of a conductive object
Data Source
AI summary
An example apparatus includes a sensing area including a sensor matrix, a first conductor and a second conductor. The first conductor is coupled to a first sensor of the sensor matrix and is configured to be coupled to a sensing module. The second conductor is coupled to a second sensor of the sensor matrix and is configured to be coupled to the sensing module. In embodiments, the first sensor consumes a first area, the second sensor and a length of the first conductor reside within a second area that is smaller than or equal to the first area consumed by the first sensor, and the length of the first conductor is routed between an edge of the sensing area and the second sensor.