Display Touch Electrode Capacitance Reduction via Air Traps
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Solution Overview
Problem
Existing touch panel technologies face challenges in enhancing touch detection accuracy and reducing noise due to increased capacitance between touch electrodes and cathode electrodes, which is limited by material permittivity changes alone.
Innovation Solution
The introduction of holes with an air trap structure between the touch electrodes and the cathode electrodes, formed in the organic insulating layer, reduces capacitance by utilizing air with lower permittivity, and the use of an inorganic masking pattern and conductive patterns to maintain hole size and connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the permittivity of materials between the touch electrode and the cathode electrode is decreased, then the capacitance between the touch electrode and the cathode electrode is reduced, but there are limitations in reducing the permittivity solely through changes in the materials
Solution Approach 1:
The insulating layer is segmented by forming holes at specific positions, dividing the continuous insulating material into regions separated by air-filled spaces. This segmentation reduces the overall permittivity between the touch electrode and cathode electrode without requiring novel material compositions, thereby reducing capacitance and improving touch detection accuracy while avoiding material selection limitations.
Solution Approach 2:
The insulating layer is transformed into a porous structure by forming holes within it. This porous configuration introduces air (with lower permittivity) into the insulating layer, effectively reducing the average permittivity between the electrodes. This approach achieves capacitance reduction through structural modification rather than material composition changes, overcoming the limitations of material selection.
2Reliability
If holes are formed in the organic insulating layer, then the capacitance between the touch electrode and the cathode electrode is reduced, but the manufacturing process becomes more complex
Solution Approach 1:
The holes are formed in the organic insulating layer before forming the inorganic insulating layer. This preliminary action allows the hole formation process to be completed when the organic layer is still accessible, avoiding the need to create complex 3D structures or perform post-processing on already-formed multi-layer stacks. The subsequent inorganic insulating layer is then formed to cover and protect the holes, integrating the complex feature into the existing manufacturing sequence.
3Reliability
If the width of holes is decreased to reduce capacitance, then the capacitance between touch electrode and cathode electrode is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The permittivity parameter is changed by introducing air-filled holes into the insulating layer rather than changing the material composition. By controlling the density, size, and distribution of holes, the effective permittivity is reduced to lower capacitance. This parameter change approach achieves the desired electrical performance while using standard manufacturing processes for hole formation, avoiding excessive precision requirements for hole width control.
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 configuration effectively reduces noise and improves touch detection accuracy by minimizing capacitance between touch electrodes and cathode electrodes, enhancing the overall performance of touch panels in display devices.
Implementation Method 1
Noise increases as the capacitance between a touch electrode and a cathode electrode increases. Research has been conducted to reduce the capacitance between the touch electrode and the cathode electrode by decreasing the permittivity of materials between the touch electrode and the cathode electrode.
Data Source
AI summary
A display device includes a base layer that includes a first area and a second area, a light-emitting-element layer disposed on the base layer and that includes a light emitting element in the first area, an encapsulation layer disposed on the light-emitting-element layer, an organic insulating layer disposed on the encapsulation layer, where holes are formed in the organic insulating layer, an inorganic insulating layer disposed on the organic insulating layer, and touch electrodes disposed on the inorganic insulating layer.