Capacitive Force Sensor in Display Panel
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Solution Overview
Problem
Current on-cell or in-cell type touch display panels cannot sense the amount of touch force applied, limiting their functionality as both output and input devices.
Innovation Solution
Incorporating a force sensor within the display panel, comprising a substrate, driving module, light emitting units, and conductive layers, where the first and second conductive layers form a capacitive force sensor that detects touch force by varying capacitance due to pressure, allowing for the calculation of touch force intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a force sensor is integrated into the display panel, then the display panel can sense touch force, but the device complexity increases
Solution Approach 1:
The force sensor is integrated into the display panel by merging the capacitive sensing function with the existing display structure. The first and second conductive layers are incorporated within the display panel layers, combining touch sensing and force sensing capabilities with the display function in a single integrated device, thereby adding versatility without proportionally increasing complexity.
Solution Approach 2:
The capacitive sensing structure serves multiple functions: it detects touch position, detects touch force through capacitance changes, and maintains compatibility with the display function. This multi-functionality approach allows the same structural elements to perform multiple sensing tasks, improving adaptability while controlling device complexity.
2Measurement precision
If conductive layers are added to detect touch force, then force sensing is enabled, but manufacturing complexity increases
Solution Approach 1:
The force sensing function is segmented into specific conductive layers (first and second conductive layers) positioned at different locations within the display panel. This segmentation allows the force sensing capability to be implemented in a modular fashion, with each layer contributing to the overall capacitance measurement, thereby enabling precise force measurement while managing manufacturing complexity through structured layering.
Solution Approach 2:
The patent utilizes changes in capacitance parameters to detect touch force. By measuring the capacitance between the first and second conductive layers, which changes in response to applied pressure, the system achieves precise force measurement. This parameter-based approach allows for accurate sensing using existing conductive layer technologies, avoiding the need for entirely new manufacturing processes.
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
Enables the display panel to effectively sense and measure touch force, enhancing its functionality as both an input and output device by integrating touch force sensing capabilities without interfering with light intensity or touch position detection.
Implementation Method 1
the first and second conductive layers form a capacitive force sensor that detects touch force by varying capacitance due to pressure
Data Source
AI summary
A display panel, which an also function as a touch input device, includes a substrate and at least one TFT on the substrate. Such a multi-function panel also includes a force sensor sensitive to pressure of touches on the panel. The force sensor includes a first conductive layer and a second conductive layer on the substrate.