Active Matrix Substrate Touch Sensor Integration
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Solution Overview
Problem
Conventional LCD panels with embedded touch sensors in the lateral electric field mode require additional photomasks for producing touch sensor lines and insulating layers, increasing production complexity and costs.
Innovation Solution
An active matrix substrate design that integrates touch sensor lines within the drain metal layer and positions them on the upper insulating layer, allowing for reduced photomask requirements by using the same conductive film for touch lines and drain electrodes, and positioning touch lines to overlap with source bus lines for improved sensitivity and reduced parasitic capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If touch sensor lines are provided as separate layers with additional insulating layers, then touch sensor functionality is achieved, but the number of photomasks and production complexity increases
Solution Approach 1:
The patent merges the touch sensor line function with the drain electrode by forming both structures from the same conductive film in the same layer. This integration eliminates the need for separate touch sensor line layers and associated insulating layers, thereby reducing the total number of photomasks required during fabrication while maintaining complete touch sensor functionality
Solution Approach 2:
The conductive film layer is designed to serve dual purposes: forming both the drain electrode for the TFT and the touch sensor lines for capacitance detection. This multi-functional design allows a single layer to fulfill multiple electrical functions, reducing structural complexity and manufacturing steps
2Reliability
If additional insulating layers are added to cover touch sensor lines, then electrical isolation is achieved, but manufacturing precision requirements increase
Solution Approach 1:
By combining the drain electrode and touch sensor line into a single formed structure from one conductive film, the patent eliminates multiple interfaces between different layers. This reduces the cumulative alignment precision requirements that would otherwise be necessary to properly position separate touch sensor line layers relative to the TFT structures
Solution Approach 2:
The patent extracts the touch sensor line formation from the separate layer structure and integrates it into the existing drain electrode formation process. This extraction of the touch sensor function from a separate layer eliminates the need for additional insulating layers and their associated alignment precision requirements
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
This design reduces the number of photomasks needed for production, enhances touch sensitivity, and maintains a high aperture ratio, facilitating the development of thinner and more efficient liquid crystal display devices with integrated touch sensors.
Implementation Method 1
an oxide semiconductor layer which is provided on the lower insulating layer; a gate insulating layer which is provided on the oxide semiconductor layer; a gate electrode which is provided across the gate insulating layer from the oxide semiconductor layer; and source and drain electrodes which are electrically connected to the oxide semiconductor layer
Implementation Method 2
a gate insulating layer which is provided on the oxide semiconductor layer; a gate electrode which is provided across the gate insulating layer from the oxide semiconductor layer
Implementation Method 3
a common electrode to be also used as an electrode for the touch sensor; and touch sensor lines which are included in the drain metal layer and each of which is electrically connected to any one of the sub common electrodes
Data Source
AI summary
An active matrix substrate includes: a source metal layer including a plurality of source bus lines; a lower insulating layer covering the source metal layer; a oxide semiconductor TFT including an oxide semiconductor layer provided on the lower insulating layer; an inter-layer insulating layer covering the oxide semiconductor TFT; a pixel electrode provided on the inter-layer insulating layer; a common electrode including a plurality of sub common electrodes each of which is capable of functioning as a touch sensor electrode; a gate metal layer including a plurality of gate bus lines and a gate electrode; a drain metal layer including the drain electrode; and a plurality of touch sensor lines included in the drain metal layer and each electrically connected to any one of the sub common electrodes.