Display Device Force Sensing Electrode Gap Design
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Solution Overview
Problem
Existing display devices with force sensing functions face challenges in detecting large pressing forces due to insufficient electrode displacement, particularly when electrodes are thin and curved, leading to reduced inter-electrode distance and compromised detection accuracy.
Innovation Solution
A display device design featuring a second force sensing electrode with a central portion and a peripheral portion surrounded by a reinforcing structure, where the gap between the central portion and the first detection electrode is greater than the gap between the peripheral portion and the first detection electrode, allowing for increased displacement and improved force detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If electrodes are formed thin to slim down the body, then device thickness is reduced, but inter-electrode distance decreases and electrode displacement becomes insufficient
Solution Approach 1:
The force sensing electrode is designed with non-uniform thickness: the central portion has a first thickness while the peripheral portion has a second thickness greater than the first. This local quality variation allows the central region to achieve sufficient displacement for accurate force detection while the peripheral regions provide structural support and maintain overall device thinness.
Solution Approach 2:
The force sensing electrode is divided into distinct regions (central portion and peripheral portion) with different thickness characteristics. This segmentation enables each region to fulfill different functions: the central region optimizes for displacement and detection accuracy, while the peripheral region optimizes for structural integrity and device thinness.
2Measurement precision
If one electrode is moved or displaced to detect large pressing force, then detection range increases, but inter-electrode distance becomes insufficient when electrodes are curved
Solution Approach 1:
The force sensing electrode implements local quality variation through thickness differentiation: the central portion with smaller thickness allows greater displacement for detecting large pressing forces, while the peripheral portion with larger thickness maintains adequate inter-electrode distance and provides structural stability.
3Stability of the object's composition
If peripheral portion of electrode is reinforced to prevent warpage, then structural stability improves, but displacement amount may be reduced
Solution Approach 1:
The electrode design applies local quality by making the peripheral portion thicker than the central portion. This thickness differentiation provides structural stability and prevents warpage in the peripheral regions while maintaining sufficient displacement capability in the thinner central region for force detection.
Solution Approach 2:
The electrode is segmented into central and peripheral portions with distinct thickness properties. This segmentation allows the peripheral portion to serve as a stable support structure that prevents warpage, while the central portion maintains the displacement freedom necessary for detecting pressing forces.
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 enables precise detection of pressing forces across the entire display area, even for larger forces, while reducing the overall thickness of the device by maintaining a sufficient displaceable amount and preventing electrode warpage.
Implementation Method 1
a display device provided with a force sensing function of sensing a pressing force applied on the display surface to thereby carry out an arbitrary operation has been proposed. Such a display device adopts an input detection mode of an electrostatic capacitance system of detecting a pressing force, in which a change in a distance between two electrodes provided in the liquid crystal display device is converted into a change in electrostatic capacitance.
Data Source
AI summary
According to one embodiment, a display device includes a display panel including a first substrate including a display area and a first detection electrode, and a second force sensing electrode opposing the display area and the first detection electrode with a gap therebetween. The second force sensing electrode includes a central portion opposing a central portion of the display region, a peripheral portion located to surround the central portion and a reinforcing structure which reinforces the peripheral portion, and the gap between the central portion and the first detection electrode is greater than a gap between the peripheral portion and the first detection electrode.