Smartphone Touch Sensor Pressure Detection
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Solution Overview
Problem
Current touch screen technologies can detect touch position but struggle to accurately measure touch pressure without degrading the performance of the display module, which often results in compromised visibility and optical transmittance.
Innovation Solution
A touch input device is designed with a capacitance type touch sensor panel and a pressure detection module that includes electrodes positioned to change distance based on touch pressure, allowing for simultaneous detection of touch position and pressure magnitude without compromising the display module's performance by using a spacer layer or integrating electrodes within the display module.
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 position detection capability is improved, but visibility and optical transmittance of the display screen are degraded
Solution Approach 1:
The touch sensor panel is integrated within the display module structure by placing it between the display screen and the front cover glass, nesting multiple functional layers (display screen, touch sensor panel, spacer layer, front cover glass) together. This allows touch detection capability to be added without compromising the optical properties of the display screen, as the touch sensor panel is positioned in a way that minimizes its impact on light transmission.
2Measurement precision
If a touch sensor panel is attached to the display screen, then touch position detection is improved, but the display module performance is degraded
Solution Approach 1:
A spacer layer is introduced as an intermediary element between the touch sensor panel and the front cover glass. This spacer layer maintains a precise distance relationship, allowing the touch sensor panel to detect touch position accurately while preventing direct contact that could degrade display module performance. The spacer layer acts as a mediator that enables both functions to coexist without interference.
3Measurement precision
If electrodes are positioned close to the touch surface for pressure detection, then pressure detection accuracy is improved, but display module performance is degraded
Solution Approach 1:
The pressure detection electrodes are nested within the multi-layer structure of the display module, positioned between the touch sensor panel and the front cover glass. This nested arrangement allows the electrodes to be close enough to the touch surface for accurate pressure detection while being protected by the surrounding layers that prevent degradation of display module performance.
Solution Approach 2:
The spacer layer serves as an intermediary that positions the pressure detection electrodes at an optimal distance from the touch surface. This intermediary structure enables accurate pressure detection by maintaining a consistent gap, while simultaneously protecting the display module performance by preventing direct contact between the electrodes and the front cover glass.
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 solution enables accurate detection of touch pressure while maintaining the display module's clarity and optical transmittance, enhancing user interaction without degrading the display quality.
Implementation Method 1
an electric signal depending on the distance is outputted from the electrode
Data Source
AI summary
In one embodiment, a touch input device capable of detecting a pressure of a touch on a touch surface is disclosed. The touch input device includes a substrate and a display module. A common voltage electrode is disposed within the display module. The touch input device further comprises an electrode which is disposed at a position where a distance between the electrode and the common voltage electrode changes according to the touch on the touch surface. The distance changes according to a magnitude of the pressure of the touch. Further, an electric signal depending on the distance is outputted from the electrode.