Force Touch Display Device with Dynamic Electrode Switching

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Solution Overview

Problem

Current touch input systems for display devices can only sense touch position and are limited in providing various functions and satisfying user demands, as they do not effectively sense touch force or pressure.

Innovation Solution

A force touch display device is developed, which includes first and second electrodes with a gap structure unit to sense touch position and force by measuring changes in capacitance, allowing for both in-cell touch and force touch modes through different driving signals, and a touch control unit that switches the second electrode based on touch location to enhance sensing accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional touch input process is used that only senses touch position, then the device structure remains simple, but the functionality is limited and cannot satisfy various user demands

Engineering Contradiction:
ImprovefunctionalityVSAvoiddevice structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The touch display device integrates both touch position sensing and touch force sensing functions into a single system. The same display panel serves as the touch sensor substrate, and the touch control unit processes both touch coordinates and touch pressure information, enabling the device to perform multiple functions (touch input and force input) without adding separate sensing systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the touch position sensing function and touch force sensing function into one integrated touch display device. The touch panel and force sensor share the same substrate structure, with the display panel serving dual purposes as both display element and touch sensing element, while the touch control unit unifiedly processes both types of input signals

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If a force touch display device with multiple electrodes and gap structure is implemented, then touch force and position sensing accuracy is improved, but the device complexity increases

Engineering Contradiction:
Improvetouch force sensing accuracyVSAvoidelectrode structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The touch sensing area is divided into multiple regions with different second electrodes (first second electrode for first touch sensing area, second second electrode for second touch sensing area). This segmentation allows independent optimization of sensing characteristics for different regions while maintaining overall system functionality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the touch display device are equipped with different electrode configurations and gap structures tailored to their specific sensing requirements. The first and second touch sensing areas have locally optimized electrode arrangements and capacitance characteristics to enhance measurement precision in each specific region

Inventive Principle:
Principle #3Local quality

3Measurement precision

If the second electrode is fixed for the entire touch sensing area, then the device structure is simple, but sensing accuracy varies across different touch locations

Engineering Contradiction:
Improvesensing accuracyVSAvoidelectrode switching mechanism
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The touch control unit dynamically switches between different second electrodes based on the detected touch position. When a touch occurs in the first touch sensing area, the first second electrode is activated; when a touch occurs in the second touch sensing area, the second second electrode is activated. This dynamic switching optimizes sensing accuracy for each local region

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The touch control unit uses feedback from the touch position detection to determine which second electrode to activate. The system continuously monitors touch coordinates and adjusts the electrode configuration accordingly, creating a closed-loop control system that optimizes sensing performance based on real-time touch location

Inventive Principle:
Principle #23Feedback

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 force touch display device effectively senses touch force and position, providing improved functionality and user experience by enabling precise detection of touch pressure across the display area, including areas where the cover bottom is cut, thereby extending the force touch sensing area.

Implementation Method 1

a force touch display device, which includes first and second electrodes with a gap structure unit to sense touch position and force by measuring changes in capacitance

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3301554B1Touch display device
Publication Date: 2022.01.26 LG DISPLAY CO LTD
  • EP3301554B1 patent drawingFigure 1
  • EP3301554B1 patent drawingFigure 2
  • EP3301554B1 patent drawingFigure 3

AI summary

There is provided a force touch display device in which a partial area of a cover bottom configured to support a back surface of a display panel is cut, and the entire area of the display device can secure uniform touch performance by selectively applying a ground (GND) signal to a mid-frame configured to support a back surface of a set device and a cut cover bottom depending on a force touch sensing area.