Polygonal Contact Electrodes for Display Touch Sensing
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Solution Overview
Problem
Display apparatuses face challenges in reducing contact resistance between sensing electrodes and bridges, which affects the accuracy and efficiency of touch sensing capabilities.
Innovation Solution
The display apparatus incorporates a sensor unit with a first conductive layer, an insulating layer, and a second conductive layer, featuring a bridge with uneven portions such as protrusions or concave sections, and contact electrodes with a polygonal cross-section that fill through-holes in the insulating layer, increasing the contact area and reducing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional planar contact electrode is used to connect the bridge and sensor portion, then the device structure remains simple, but the contact resistance between the bridge and sensor portion increases
Solution Approach 1:
The contact electrode transitions from a conventional planar (2D) structure to a three-dimensional structure with vertical walls and uneven surfaces. This dimensional change increases the contact area between the bridge and sensor portion, thereby reducing contact resistance while maintaining structural integrity
Solution Approach 2:
The contact electrode is divided into multiple segments including a first contact portion, second contact portion, and third contact portion with different functions. The first contact portion connects to the bridge, the second connects to the sensor portion, and the third provides vertical walls. This segmentation allows each portion to be optimized for its specific function, improving overall electrical connection while managing structural complexity
2Reliability
If the contact area between bridge and sensor portion is increased to reduce contact resistance, then the electrical characteristics improve, but the manufacturing complexity increases
Solution Approach 1:
The contact electrode's geometric parameters are optimized to achieve the desired contact area. By controlling the width, height, and uneven surface characteristics of the contact electrode, the patent achieves reduced contact resistance while maintaining compatibility with existing manufacturing processes
Solution Approach 2:
The contact electrode exhibits local quality variations with different portions having different properties. The first contact portion has a larger area for bridge connection, the second contact portion interfaces with the sensor portion, and the vertical walls provide additional contact pathways. This localized optimization improves electrical characteristics without requiring complete restructuring of the entire electrode
Data Source
AI summary
A display apparatus includes a display panel (DP) and a sensor unit on the DP. The sensor unit includes: a first conductive layer (CL) including a first bridge (FB); a second CL disposed on the first CL, the second CL including first sensor portions (FSPs) spaced apart from each other and arranged in a first direction; a first insulating layer (IL) disposed between the first CL and the second CL, the first IL including through-holes (THs) extending between the FB and the FSPs overlapping the FB; and contact electrodes (CEs) filling spaces defined by a bridge top surface of the FB exposed by the THs, insulating sidewalls of the first IL defining the THs, and sensor bottom surfaces of the FSPs facing the FB. A cross-section, which is perpendicular to a top surface of the DP, of each of the CEs has a polygonal shape of five or more sides.