Touch Electrode Parasitic Capacitance Uniformity
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Solution Overview
Problem
In display apparatuses, the varying lengths of touch lines lead to different parasitic capacitances for touch electrodes, affecting touch sensitivity and reliability.
Innovation Solution
The display apparatus design includes touch electrodes connected to both a first touch line and a second touch line, where the sum of their distances is constant, with both lines made of the same material and disposed on the same layer as the electrodes, ensuring equal parasitic capacitance and improved touch reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If touch lines are extended to connect touch electrodes at different locations, then touch coverage area is improved, but parasitic capacitance difference increases
Solution Approach 1:
The touch line connection is segmented into two separate lines (first touch line and second touch line) that extend in opposite directions from the touch electrode. This segmentation allows each line to be optimized independently, with their combined length maintained constant to ensure uniform parasitic capacitance across all touch electrodes regardless of their position on the display apparatus.
Solution Approach 2:
The patent changes the configuration parameters of the touch lines by specifying that they extend in opposite directions (first direction and second direction) from the touch electrode. By controlling the lengths of these lines such that their sum remains constant, the parasitic capacitance parameter is standardized across different touch electrode locations, resolving the sensitivity uniformity issue.
2Adaptability or versatility
If touch line length varies by electrode location, then device layout flexibility is improved, but parasitic capacitance uniformity deteriorates
Solution Approach 1:
The patent applies the equipotentiality principle by ensuring that all touch electrodes have equivalent electrical characteristics in terms of parasitic capacitance. This is achieved by configuring the first and second touch lines such that their combined length is constant for all touch electrodes, creating an equipotential condition for signal transmission across the entire touch sensing area.
Solution Approach 2:
While maintaining overall symmetry in the touch electrode arrangement, the patent introduces asymmetric line configurations where the first and second touch lines extend in opposite directions with potentially different individual lengths. The key is that their sum remains constant, allowing asymmetric adaptation to different electrode positions while maintaining uniform electrical characteristics.
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 reduces parasitic capacitance differences and enhances touch sensitivity and reliability by maintaining consistent capacitance across touch electrodes, regardless of their location.
Implementation Method 1
A parasitic capacitance due to each touch line can be proportional to a length of the corresponding touch line. That is, in the display apparatus, each of the touch electrodes can have a parasitic capacitance different from each other.
Data Source
AI summary
A display apparatus is provided. The display apparatus includes touch electrodes on an encapsulating element. Each of the touch electrodes can be connected to a first touch line extending in a direction, and a second touch line extending in a direction opposite to the first touch line. Each of the touch electrodes can be connected to one of touch pads by one of the first touch lines. The second touch line can include an end on the encapsulating element. Thus, in the display apparatus, the reliability for the touch of a user or tool can be improved.