Detection Substrate Hollowed Electrode Design for Capacitive Touch Sensitivity
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Solution Overview
Problem
Capacitive touch screens face issues with varying parasitic capacitance between touch sensing electrodes and signal lines, leading to uneven display brightness and transverse mura due to differences in parasitic capacitance between signal lines and touch electrodes, affecting detection sensitivity and accuracy.
Innovation Solution
A detection substrate with a base substrate featuring outer and inner detection electrodes, where the outer detection electrode has hollowed portions corresponding to the inner detection electrodes, and orthographic projections of the inner electrodes overlap with regions surrounded by the edge of the hollowed portions, enhancing mutual capacitance and detection sensitivity by staggering inner detection electrodes and signal lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional capacitive touch screen electrodes are used without hollowed portions, then the structure is simple, but the mutual capacitance between touch electrodes is insufficient leading to low detection sensitivity
Solution Approach 1:
The patent converts the harmful effect of parasitic capacitance into a beneficial effect by designing hollowed portions in the outer detection electrode that correspond to inner detection electrodes. This structure increases the mutual capacitance between touch electrodes while the curved portions of the hollowed edges further enhance the electric field coupling, transforming the parasitic capacitance problem into an advantage for improving detection sensitivity
Solution Approach 2:
The patent applies curvature by designing the edges of the hollowed portions with curved portions rather than straight lines. This curved geometry increases the surface area and optimizes the electric field distribution between the outer and inner detection electrodes, thereby enhancing the mutual capacitance and detection sensitivity without significantly increasing structural complexity
2Illumination intensity
If signal lines are arranged without considering electrode overlap, then layout is simple, but parasitic capacitance varies causing transverse mura and uneven display brightness
Solution Approach 1:
The patent applies local quality by staggering the arrangement of inner detection electrodes and signal lines in specific regions. This local optimization ensures that signal lines overlap with both outer and inner detection electrodes uniformly across different areas of the touch screen, maintaining consistent parasitic capacitance values and achieving uniform display brightness without requiring complete redesign of the entire layout
3Measurement precision
If outer and inner detection electrodes are placed close together, then mutual capacitance increases improving detection, but parasitic capacitance with signal lines increases causing transverse mura
Solution Approach 1:
The patent applies segmentation by dividing the detection electrode structure into outer and inner components with hollowed portions. This segmentation allows the inner detection electrodes to be positioned close to outer electrodes for high mutual capacitance, while the hollowed portions create spatial separation that reduces parasitic capacitance coupling with signal lines, thereby resolving the contradiction between detection sensitivity and parasitic capacitance effects
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 solution improves detection sensitivity and reduces transverse mura by increasing the effective mutual capacitance between outer and inner detection electrodes, allowing for accurate touch positioning and fingerprint recognition with enhanced sensitivity.
Implementation Method 1
The working principle of the capacitive touch screens includes that a conductive material is provided on a surface of a substrate as a touch electrode, and in the case where a touch object (for example, a user's finger) touches the touch screen, a capacitance of a touch electrode located at a touch point changes
Implementation Method 2
The at least one outer detection electrode has at least one hollowed portion, the at least one hollowed portion corresponds to the at least one inner detection electrode, and at least one orthographic projection of the at least one inner detection electrode on the base substrate respectively overlaps with at least one region respectively surrounded by at least one orthographic projection of at least one edge of the at least one hollowed portion on the base substrate
Data Source
AI summary
A detection substrate and a display device are disclosed. The detection substrate includes an outer detection electrode and an inner detection electrode on a base substrate and insulated from each other. The outer detection electrode has a hollowed portion, and the hollowed portion corresponds to the inner detection electrode. The inner detection electrode includes a body portion and a plurality of protrusion portions protruding from the body portion and extending in directions away from the body portion. The edge of the hollowed portion includes a curved portion, an orthographic projection of the curved portion on the base substrate protrudes into a region between orthographic projections of at least two adjacent protrusion portions of the plurality of protrusion portions on the base substrate, a portion of the orthographic projection of the curved portion is closer to an orthographic projection of the body portion on the base substrate.