Touch Sensor Routing for Reduced Bezel Area
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Solution Overview
Problem
Large-sized or high-resolution touch screens face an increased non-display area due to the number of touch electrodes and routing lines, leading to a larger bezel area, which is inefficient in terms of space utilization.
Innovation Solution
The display device incorporates a substrate with a display area and a non-display area, featuring a touch sensor system with first and second touch electrode lines, routing wirings, and pads, where the touch electrode lines are strategically arranged to minimize the non-display area by using internal and external routing wirings and ground wirings, and a dam is placed near the boundary to prevent encapsulation layer overflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of touch electrodes is increased for large-sized or high-resolution touch screens, then the touch sensing capability is improved, but the non-display area (bezel area) increases due to more routing lines
Solution Approach 1:
The patent utilizes the third dimension (vertical stacking) by placing touch electrode lines and routing wirings on different layers of the encapsulation layer. Multiple touch electrode lines extend in different directions (first direction and second direction) and are connected through vertically stacked routing wirings, allowing efficient connection of numerous touch electrodes without increasing the horizontal footprint of the bezel area.
Solution Approach 2:
The patent implements a nested structure where routing wirings are disposed between touch electrode lines in a stacked configuration. The first routing wiring connects first touch electrode lines, while the second routing wiring connects second touch electrode lines, with these routing wirings positioned between the electrode lines in the vertical dimension. This nesting allows multiple connections to be made within the same horizontal space.
2Adaptability or versatility
If routing lines are added to connect increased touch electrodes, then touch coverage is improved, but the bezel area size increases
Solution Approach 1:
The patent extends touch coverage by adding touch electrode lines in both first and second directions across the display area, connecting them through vertically stacked routing wirings. This multi-directional arrangement with vertical stacking enables comprehensive touch coverage across large display areas without proportionally increasing the horizontal bezel dimensions.
Solution Approach 2:
The patent merges multiple routing functions into a compact stacked structure where first routing wirings and second routing wirings are disposed between touch electrode lines in the vertical dimension. This consolidation allows multiple electrical connections to be achieved within the same horizontal footprint, reducing the overall bezel area required for routing.
3Measurement precision
If more routing lines are used to connect touch electrodes to the touch driving circuit, then touch sensing accuracy is improved, but the non-display area increases
Solution Approach 1:
The patent places routing wirings in a nested configuration between touch electrode lines, with first routing wirings connecting first touch electrode lines and second routing wirings connecting second touch electrode lines. This nested arrangement maintains precise electrical connections for accurate touch sensing while minimizing the horizontal space occupied by routing infrastructure.
Solution Approach 2:
The patent transitions routing connections from a horizontal planar arrangement to a vertical stacked arrangement, allowing multiple routing lines to occupy the same horizontal footprint by stacking them in the vertical dimension. This preserves touch sensing accuracy through adequate routing connections while reducing the non-display area required for these connections.
Data Source
AI summary
A display device comprises a substrate including a display area having subpixels and a non-display area excluding the display area, an encapsulation layer that covers the subpixels, a first touch electrode line including a plurality of first touch sensing electrodes in a first direction on the encapsulation layer and spaced apart from each other in the first direction, a second touch electrode line in a same plane as the first touch electrode line and disposed in a second direction, a plurality of pads on one side of the substrate, a first touch routing wiring that connects some of the first touch electrode line and some pads among the plurality of pads and disposed between the plurality of first touch sensing electrodes in the second direction, and a second touch routing wiring that connects the second touch electrode line to some other pads among the plurality of pads.