Touch Sensor System with Minimized Inactive Borders
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Solution Overview
Problem
Existing touch sensors for electronic devices often have excessively large inactive borders, which are aesthetically unpleasing and result in bulky devices, as they require opaque metal signal lines that need to be hidden, increasing the width of the inactive areas.
Innovation Solution
A two-dimensional touch sensor system with minimized inactive regions, utilizing distinct vertical and horizontal position sensors based on different technologies, such as capacitive, force, or light-based sensors, where the horizontal position sensor structures are formed on a transparent substrate and the vertical position sensors are placed at the edges, reducing the need for opaque masking and minimizing inactive border widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional capacitive touch sensor arrays with metal signal lines are used, then touch detection capability is achieved, but inactive border width increases due to opaque masking requirements
Solution Approach 1:
The touch sensor is divided into separate horizontal and vertical sensor arrays that can be independently optimized. The horizontal sensors use transparent electrodes while vertical sensors use opaque electrodes, allowing each to be positioned and designed optimally without requiring large inactive borders for signal line routing
Solution Approach 2:
The patent transitions from a single two-dimensional capacitive sensor array to a composite system combining one-dimensional horizontal and vertical sensor arrays. This dimensional decomposition allows the sensors to be arranged along the edges of the active display area, minimizing the inactive border width while maintaining full touch detection capability across the display surface
2Shape
If opaque masking layers are added to hide metal signal lines, then aesthetic appearance is improved, but device thickness and complexity increase
Solution Approach 1:
The patent extracts the signal line routing function from the sensor electrode structure itself. By using separate horizontal and vertical sensor arrays with electrodes oriented perpendicular to each other, the need for complex peripheral signal line routing and associated opaque masking layers is eliminated, reducing device complexity and thickness
Solution Approach 2:
The patent applies different electrode transparency properties to different sensor orientations: horizontal sensors use transparent electrodes where they intersect the display active area, while vertical sensors use opaque electrodes positioned along the edges. This local differentiation eliminates the need for extensive opaque masking layers while maintaining aesthetic appearance
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 minimizes the inactive border regions, enhancing the aesthetics and compactness of electronic devices by reducing the width of inactive areas, allowing for more streamlined device designs while maintaining effective touch input detection capabilities.
Implementation Method 1
The capacitive touch sensor electrodes can be formed from a material such as indium tin oxide that is both conductive and transparent
Implementation Method 2
The position sensors may be based on strain gauge sensors or other force sensors
Data Source
AI summary
An electronic device may be provided with a touch screen display. The touch screen display may have an array of display pixels that are used to display images for a user. Touch input to the touch screen display may be provided by a user's finger or other external object. A touch sensor in the display may have vertical and horizontal position sensors that are based on distinct touch sensor technologies. The position sensors may be based on strain gauge sensors or other force sensors, capacitive sensors having multiple elongated transparent capacitive electrodes that span the display, acoustic sensors, light-based sensors, and other types of sensors. An opaque masking layer in an inactive area of the display may hide some of the position sensor structures from view such as vertical position sensor structures. The horizontal position sensor structures may have minimal inactive regions along their edges.