Data Line Shielding for Touch Sensor Noise
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Solution Overview
Problem
Noise from display circuitry can interfere with the functionality of touch sensor circuitry in electronic devices, degrading accuracy and performance.
Innovation Solution
Incorporating data line shielding structures, such as routing lines or mesh-like conductive structures, directly over and covering data lines, which can be biased to various voltage levels and driven using dedicated shielding line bias drivers, to minimize signal coupling between data line signals and touch sensor circuitry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If data line shielding structures are added to reduce noise coupling, then touch sensor accuracy is improved, but device complexity increases
Solution Approach 1:
The shielding structures are merged with the existing display structure by forming them as conductive layers within the display device layers. The shielding lines are integrated into the data line structure itself, using the same transparent conductive oxide materials and formation processes as the display circuitry, thereby reducing noise coupling without adding separate external shielding components.
Solution Approach 2:
The patent introduces intermediate shielding layers positioned between the data lines and touch sensor circuitry. These shielding layers act as mediators that block electromagnetic coupling while maintaining the functional integrity of both the display and touch sensing systems. The shielding structures are positioned at strategic intermediate locations within the layered display architecture.
2Object-affected harmful factors
If multiple planarization layers are added to accommodate shielding structures, then signal coupling is reduced, but manufacturing complexity increases
Solution Approach 1:
The planarization layers serve multiple functions simultaneously: they provide surface flatness for subsequent layer deposition, act as dielectric insulation layers, and serve as structural support for the shielding conductors. By making the planarization layers multi-functional, the patent avoids adding extra dedicated shielding layers that would increase manufacturing complexity.
Solution Approach 2:
The patent modifies the electrical parameters of existing layers by adjusting their conductivity and thickness to achieve shielding functionality. The planarization layers are engineered with specific dielectric properties and conductor patterns that transform them into effective shielding structures without requiring fundamental changes to the manufacturing process.
3Object-affected harmful factors
If dedicated shielding line bias drivers are implemented, then noise mitigation is improved, but device complexity increases
Solution Approach 1:
The shielding structures are designed to be self-regulating through their connection to existing power supply networks. The shielding layers are connected to power supply lines (such as ELVDD or ELVSS) that already exist in the display device, allowing them to automatically establish appropriate bias voltages without requiring external control circuits or additional driver complexity.
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
The implementation of data line shielding structures effectively reduces noise coupling, improving the accuracy and performance of touch sensor functionality while minimizing undesired display artifacts.
Implementation Method 1
The display circuitry may include data line shielding structures for mitigating signal coupling between the data line signals and the touch sensor circuitry
Data Source
AI summary
An electronic device may have a display with touch sensors. One or more shielding layers may be interposed between the display and the touch sensors. The display may include transistors with gate conductors, a first planarization layer formed over the gate conductors, one or more contacts formed in a first source-drain layer within the first planarization layer, a second planarization layer formed on the first planarization layer, one or more data lines formed in a second source-drain layer within the second planarization layer, a third planarization layer formed on the second planarization layer, and a data line shielding structure formed at least partly in a third source-drain layer within the third planarization layer. The data line shielding structure may be a routing line, a blanket layer, a mesh layer formed in one or more metal layers, and/or a data line covering another data line.