Rear Electrode Sheet Layout for Pressure-Sensing Touch Displays
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Solution Overview
Problem
Existing touch input devices struggle to detect touch pressure with a certain magnitude at specific touch positions on a touch screen without degrading the performance of the display panel, which affects the accuracy and sensitivity of touch input operations.
Innovation Solution
A touch input device is designed with a display panel and an electrode sheet that includes a first and second insulation layer with an electrode between them, allowing for capacitance changes to be detected based on the relative distance change between the electrode sheet and a reference potential layer, enabling differential capacitance change detection across different areas of the touch surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a touch sensor panel is attached to the front side of a display screen to enable touch detection, then touch input capability is improved, but the visible side of the display screen is covered and display performance is degraded
Solution Approach 1:
The patent moves the touch sensor panel from the front side (2D surface attachment) to the rear side of the display panel, utilizing the third dimension (depth/thickness) of the display structure. This allows the touch sensor panel to be positioned at a different spatial location that does not interfere with the display's light output, thereby maintaining both touch functionality and display visibility.
2Device complexity
If the touch sensor panel is positioned closer to the display panel to improve integration, then device complexity is reduced, but touch pressure detection accuracy deteriorates
Solution Approach 1:
The patent introduces an intermediary space (rear side of the display panel) and intermediary components (adhesive layers, spacer structures) that maintain an optimal distance between the touch sensor panel and display panel. This intermediary positioning allows for sufficient capacitance change detection while maintaining integrated device structure, resolving the contradiction between integration and detection accuracy.
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 solution allows for precise detection of touch pressure and position on a touch screen without compromising the display panel's performance, enhancing the sensitivity and accuracy of touch input operations by varying the capacitance change amount based on the touch position.
Implementation Method 1
When a pressure is applied to the touch surface, a distance between the electrode and a reference potential layer may be changed. A capacitance which is detected at the electrode is changed according to the distance change.
Data Source
AI summary
A touch input device capable of detecting a pressure of a touch on a touch surface may be provided that includes: a display panel; and an electrode disposed under the display panel. When a pressure is applied to the touch surface, a distance between the electrode and a reference potential layer is changed. A capacitance which is detected at the electrode is changed according to the distance change. The display panel includes a first area and a second area. Under a same distance change condition, a capacitance change amount detected at the electrode disposed under the second area is greater than a capacitance change amount detected at the electrode disposed under the first area.