In-cell Touch Panel Pressure Sensing via Capacitance Variation
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Solution Overview
Problem
Current pressure-sensitive technologies in display fields, such as mobile phones and tablets, face challenges in achieving high detection accuracy with minimal hardware modification, particularly in the integration of additional mechanisms with liquid crystal display (LCD) panels.
Innovation Solution
An in-cell touch panel design incorporating organic light-emitting diode (OLED) pixel units with pressure-sensitive detection electrodes and a chip that detects capacitance variations between these electrodes and the cathode layer, allowing for pressure-sensitive detection without significant structural changes to the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an additional mechanism is added to the LCD panel for pressure sensing, then pressure-sensitive functionality is achieved, but device complexity and structural modification increase
Solution Approach 1:
The patent combines the touch sensing function and pressure sensing function into a single integrated structure. The touch sensor includes both a touch detection electrode and a pressure detection electrode formed on the same substrate, eliminating the need for separate additional mechanisms and reducing device complexity while maintaining pressure-sensitive functionality.
Solution Approach 2:
The sensor substrate serves multiple functions: it acts as both the touch sensing component and the pressure sensing component. The same substrate integrates both touch detection and pressure detection capabilities, making the system more versatile without requiring separate dedicated structures for each function.
2Adaptability or versatility
If an additional mechanism is added to the LCD panel for pressure sensing, then pressure-sensitive functionality is achieved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the touch sensor and pressure sensor manufacturing processes into a single integrated fabrication sequence. Both detection electrodes are formed on the same substrate using compatible materials and processes, simplifying manufacturing and reducing production complexity compared to adding separate pressure sensing mechanisms.
Solution Approach 2:
The patent uses parameter changes in the electrode design, such as varying the shape, size, and arrangement of detection electrodes, to achieve both touch and pressure sensing functions within the same manufacturing framework. This allows for functional differentiation through geometric parameters rather than requiring different manufacturing processes.
3Measurement precision
If detection accuracy is improved by reducing fit tolerance, then measurement precision increases, but manufacturing difficulty increases
Solution Approach 1:
The patent employs self-alignment mechanisms where the detection electrodes are formed in direct contact with or in close proximity to the OLED pixel units on the same substrate. This self-service approach eliminates the need for precise mechanical fitting and assembly, as the electrodes automatically align with the underlying structures during the fabrication process, thereby improving detection accuracy without increasing manufacturing difficulty.
Solution Approach 2:
The patent replaces mechanical fitting and assembly mechanisms with a planar integrated structure where all components are formed on the same substrate. This substitution of mechanical systems with a monolithic integrated design eliminates fit tolerance issues and achieves high detection accuracy through precise pattern formation during fabrication rather than through mechanical assembly.
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 enhances detection accuracy while minimizing hardware modifications and production costs, achieving effective pressure-sensitive touch functionality with improved light transmittance uniformity and reduced production complexity.
Implementation Method 1
determine a pressure value at a touch position by detecting a capacitance variation between the pressure-sensitive detection electrodes and the cathode layer
Implementation Method 2
a plurality of organic light-emitting diode (OLED) pixel units disposed on a side of the base substrate facing the opposing substrate
Data Source
AI summary
An in-cell touch panel, driving method thereof and display device are provided. The in-cell touch panel includes: a base substrate; an opposing substrate arranged opposite to the base substrate; a plurality of organic light-emitting diode pixel units disposed on a side of the base substrate facing the opposing substrate, wherein each of the OLED pixel units include an anode layer; a pressure-sensitive detection chip; and a plurality of mutually independent pressure-sensitive detection electrodes disposed between the cathode layer and the opposing substrate, wherein a capacitor structure is formed by the pressure-sensitive detection electrodes and the cathode layer, wherein the pressure-sensitive detection chip is configured to determine a pressure value at a touch position by detecting a capacitance variation between the pressure-sensitive detection electrodes and the cathode layer.