Active Matrix Substrate Touch Sensor Aperture Ratio
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Solution Overview
Problem
In lateral-field mode liquid crystal display panels with touch sensing, the integration of touch wiring and pixel electrodes leads to a decrease in pixel aperture ratio, affecting light transmittance and display performance.
Innovation Solution
An active matrix substrate design that includes a common electrode with a dielectric layer, touch wiring lines, and optimized contact portions to minimize overlap with pixel electrodes, using an oxide semiconductor layer and specific aperture configurations to maintain light transmittance while enabling touch sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If touch wiring contact portions are formed in the displaying region to connect sensor electrodes and touch wiring lines, then touch sensing functionality is enabled, but the pixel aperture ratio decreases
Solution Approach 1:
The patent combines the pixel electrode and touch wiring contact portion into a unified structure. The pixel electrode is extended to directly connect with the touch wiring line, eliminating the need for separate contact portions. This merging approach allows touch sensing functionality to be implemented while minimizing the additional area occupied, thereby preserving the pixel aperture ratio.
Solution Approach 2:
The patent designs the pixel electrode to serve dual functions: as the display electrode for liquid crystal control and as the contact portion for touch wiring connection. By making the pixel electrode itself conductive and extending it to connect with touch wiring lines, the structure achieves multi-functionality, enabling touch sensing without requiring separate dedicated contact areas that would reduce the aperture ratio.
2Adaptability or versatility
If the common electrode is provided on the pixel electrodes with a dielectric layer interposed, then touch sensing is enabled, but the structural complexity increases
Solution Approach 1:
The patent merges the common electrode function with the pixel electrode structure. Instead of adding a separate common electrode layer with dielectric isolation, the pixel electrode itself is designed to function as the common electrode for touch sensing. This integration reduces structural complexity while maintaining touch sensing capability.
Solution Approach 2:
The pixel electrode is designed to perform multiple functions simultaneously: display function by controlling liquid crystal and touch sensing function by serving as the common electrode. This multi-functionality eliminates the need for separate common electrode structures and dielectric layers, thereby reducing overall structural complexity while enabling touch sensing.
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
The design effectively suppresses the decrease in pixel aperture ratio, enhancing light transmittance and display performance by reducing the geometric area of contact portions without compromising touch sensing functionality.
Implementation Method 1
a TFT supported on the principal face of the substrate and disposed for each of the plurality of pixel regions
Implementation Method 2
a change in electrostatic capacity that is caused by contact or approach of an object (e.g., a finger) is electrically detected
Implementation Method 3
a pair of electrodes for touch sensing (a transmitter electrode and a receiver electrode) are used to generate an electric field
Implementation Method 4
the common electrode being provided on the plurality of pixel electrodes with a dielectric layer interposed therebetween
Data Source
AI summary
An active matrix substrate includes: a TFT being disposed on each of a plurality of pixel regions and including an oxide semiconductor layer; an interlayer insulating layer covering the TFT; and a plurality of pixel electrodes, a common electrode including a plurality of common electrode subportions, and a plurality of first wiring lines which are disposed on the interlayer insulating layer. Source and drain electrodes of the TFT are disposed on the oxide semiconductor layer via an upper insulating layer; the source electrode and the drain electrode are electrically connected to the oxide semiconductor layer within, respectively, a source-side aperture and a drain-side aperture which are made in the upper insulating layer; the active matrix substrate further includes a first contact portion which connects the drain electrode with one of the pixel electrodes and a second contact portion which connects one of the common electrode subportions with one of the first wiring lines; and, when viewed from a normal direction of a principal face of the substrate, the first contact portion at least partially overlaps the drain-side aperture, and the second contact portion at least partially overlaps the source-side aperture of the TFT that is disposed in one of the plurality of pixel regions.