Display Device Detection Electrodes Parasitic Capacitance Reduction
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Solution Overview
Problem
In display devices with a common electrode and detection electrodes, crosstalk can occur due to parasitic capacitance between signal lines and detection electrodes, particularly affecting blue and white sub-pixels, leading to deterioration of display quality.
Innovation Solution
The display device incorporates a matrix arrangement of detection electrodes overlapping sub-pixels, with signal supply wires coupled to detection electrodes, and dummy contact holes formed to reduce parasitic capacitance, specifically in regions overlapping signal lines coupled to blue and white sub-pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If detection electrodes are arrayed in a matrix configuration overlapping sub-pixels, then touch detection capability is improved, but parasitic capacitance between signal lines and detection electrodes increases causing crosstalk
Solution Approach 1:
The detection electrodes are segmented into multiple independent electrodes arranged in a matrix configuration, allowing individual control and reduced mutual interference. Each detection electrode can be independently driven and read, which helps isolate parasitic capacitance effects to specific regions rather than affecting the entire sensor array.
Solution Approach 2:
Different regions of the display device have different structural characteristics. The signal line configuration varies by region - some regions have signal lines passing underneath detection electrodes while others have detection electrodes positioned above signal lines. This local variation optimizes the balance between touch detection coverage and parasitic capacitance reduction in different areas of the display.
2Area of stationary object
If signal lines are positioned to overlap detection electrodes for compact layout, then device area is reduced, but parasitic capacitance increases causing display quality deterioration
Solution Approach 1:
The patent utilizes vertical stacking to resolve the spatial conflict between signal lines and detection electrodes. Instead of only horizontal arrangement, the structure employs multiple layers where signal lines and detection electrodes are positioned at different vertical levels, connected through contact holes. This three-dimensional arrangement reduces parasitic capacitance while maintaining compact footprint.
Solution Approach 2:
Insulating films are introduced as intermediary layers between signal lines and detection electrodes where they must overlap. These insulating barriers reduce direct capacitive coupling while still allowing electrical connection through controlled contact holes, thus mediating the conflict between compact layout and parasitic capacitance reduction.
Data Source
AI summary
A display device includes a plurality of first sub-pixels configured to display red, a plurality of second sub-pixels configured to display green, a plurality of third sub-pixels configured to display blue, and a plurality of fourth sub-pixels configured to display white, a first signal line coupled to the first sub-pixels, a second signal line coupled to the second sub-pixels, and a third signal line coupled to the third sub-pixels and the fourth sub-pixels, a plurality of detection electrodes arrayed in a matrix (row-column configuration) and each provided overlapping the first sub-pixels, the second sub-pixels, the third sub-pixels, and the fourth sub-pixels, and a plurality of signal supply wires coupled to the respective detection electrodes. The signal supply wires are each provided overlapping at least one of the first signal line and the second signal line and not overlapping the third signal line.