Array Substrate Touch Line Layering for Aperture Ratio
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Solution Overview
Problem
Self-capacitance touch panels have a low aperture ratio, which restricts brightness enhancement and is a result of the parallel arrangement of touch lines and source/drain electrodes in the same layer, leading to reduced light transmission.
Innovation Solution
The touch line and source electrode are arranged in different layers, with overlapping orthographic projections on the base, reducing the opaque wiring region and increasing the light transmission area, thereby enhancing the aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If touch lines and source/drain electrodes are arranged in the same layer in parallel, then the manufacturing process is simplified, but the aperture ratio is reduced due to increased opaque wiring region
Solution Approach 1:
The patent applies dimensionality change by transitioning from a two-dimensional parallel arrangement (same layer) to a three-dimensional stacked arrangement (different layers). The touch line is moved from the same layer as source/drain electrodes to a different layer, creating vertical stacking. This spatial reconfiguration reduces the opaque wiring region in the planar view while maintaining electrical connectivity through vertical vias, thereby increasing the aperture ratio without significantly complicating the manufacturing process.
2Device complexity
If touch lines are placed in the same layer as source/drain electrodes, then device complexity is reduced, but light transmission is blocked leading to lower brightness
Solution Approach 1:
The patent resolves the brightness issue by moving the touch line to a different layer, creating a vertical stack where the touch line in the second layer overlaps with the source/drain electrode in the first layer. This dimensional change allows light to pass through the first layer more effectively while the touch line provides shielding from the second layer, thereby increasing overall light transmission and brightness without significantly increasing device complexity.
Solution Approach 2:
The patent converts the harmful shielding effect of the touch line into a beneficial feature. By positioning the touch line in the second layer to overlap with the source/drain electrode in the first layer, the touch line's shielding effect is localized to specific regions, actually protecting the underlying structures while allowing light transmission through non-overlapping areas. This converts the previously harmful full-layer shielding into a beneficial localized shielding that improves overall optical performance.
3Area of stationary object
If touch lines and source/drain electrodes overlap in different layers, then aperture ratio is increased, but manufacturing precision requirements are elevated due to multi-layer alignment
Solution Approach 1:
The patent addresses alignment precision by utilizing the third dimension (vertical stacking) to resolve planar overlap issues. The touch line in the second layer is designed to overlap with the source/drain electrode in the first layer, creating a vertical configuration that maximizes light transmission in the planar view. The multi-layer structure with via holes provides natural alignment references, and the vertical stacking tolerates certain lateral misalignments better than planar arrangements, thereby achieving high aperture ratio with manageable manufacturing precision requirements.
Data Source
AI summary
An array substrate is provided. The array substrate includes a base, a first electrode and a second electrode which are on the base and a touch line on the base, both the first electrode and the second electrode are configured to transmit a display signal, the touch line is configured to transmit a touch signal; the first electrode and the touch line are respectively in different layers, and an orthographic projection of the first electrode on the base at least partially overlaps with an orthographic projection of the touch line on the base. A preparation method of the array substrate and a touch display panel are further provided.