Touch Display Driving Circuit for Simultaneous Position and Force Sensing

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Solution Overview

Problem

Current touch-type user interfaces are limited in detecting multiple functions and user demands, as they primarily focus on sensing touch coordinates and pressure, failing to efficiently handle diverse and complex interactions on touch screens.

Innovation Solution

A driving circuit and touch display device that utilize electrodes of a single type for simultaneous display, touch sensing, and force sensing operations, allowing for the detection of touch position and force during a single touch event, and enabling the detection of multiple touches through force sensing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple types of electrodes are used for display, touch sensing, and force sensing, then sensing accuracy and functionality are improved, but device complexity increases

Engineering Contradiction:
Improvesensing functionalityVSAvoidelectrode structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies multi-functionality by enabling a single electrode type to serve multiple purposes: display function, touch sensing function, and force sensing function. The driving circuit selectively applies different driving signals to the same electrode structure based on the required function, eliminating the need for separate electrode layers for each function and thereby reducing device complexity while maintaining versatility.

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

Solution Approach 2:

The patent employs dynamics by making the electrode's function changeable through dynamic signal application. The same physical electrode structure can be dynamically assigned to different functions (display, touch sensing, or force sensing) by controlling the driving signals, allowing the system to adapt its functionality without physical reconfiguration.

Inventive Principle:
Principle #15Dynamics

2Measurement precision

If separate operating modes are used for display and sensing, then sensing performance is improved, but response time and productivity are reduced

Engineering Contradiction:
Improvesensing performanceVSAvoidresponse time
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent implements continuity of useful action by enabling the electrode to perform both display and sensing functions within the same operating period without switching between separate modes. The driving circuit can simultaneously or sequentially apply display driving signals and sensing detection signals to the same electrode, ensuring continuous functionality and eliminating idle transition times between modes.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent applies periodic action through the driving circuit's ability to cycle through different signal types (display signals and sensing signals) in a structured sequence. This periodic switching allows the system to maintain both display and sensing capabilities within a single frame period, improving response time while preserving sensing performance.

Inventive Principle:
Principle #19Periodic action

3Adaptability or versatility

If only touch coordinates are detected, then device complexity is reduced, but adaptability to diverse user demands is limited

Engineering Contradiction:
Improveuser interaction capabilitiesVSAvoidsensing system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extends multi-functionality beyond spatial touch detection to include force sensing capabilities. The same electrode structure used for touch coordinate detection is also utilized for force sensing by applying appropriate driving signals, enabling the system to detect multiple interaction parameters (position, pressure, and potentially other force characteristics) without adding separate sensing hardware.

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

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 user interaction by efficiently sensing touch position and force, reducing the number of operating modes and improving display and sensing performance, enabling a broader range of functions on touch screens.

Implementation Method 1

By detecting changes in capacitance at each of the touch pixels and noting the position of the touch pixels, the touch sensing system can recognize multiple objects

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The sensor unit is configured to detect a change in capacitance between the first and second electrodes upon a change in position of the input portion relative to the first substrate from a touch on to the input portion

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3208698B1Driving circuit, touch display device, and method of driving the touch display device
Publication Date: 2022.03.09 LG DISPLAY CO LTD
  • EP3208698B1 patent drawingFigure 1
  • EP3208698B1 patent drawingFigure 2
  • EP3208698B1 patent drawingFigure 3A

AI summary

A driving circuit (120), a touch display device (100), and a method of driving the touch display device (100). A plurality of first electrodes (El) are disposed within a display panel (110). A second electrode is disposed outside of the display panel (110). A driving circuit (120) detects at least one of a touch position and a touching force of a touch by sequentially applying a first electrode driving signal (DS1) to at least one first electrode among the plurality of first electrodes (El) and applying a second electrode driving signal (DS2) to the second electrode in a touch driving period. When a user touches a screen, not only can a touch position be sensed, but also a touching force with which the user presses the screen can also be efficiently sensed. This provides a range of functions that existing touch position-detecting technologies have failed to provide.