In-Cell Touchscreen Stylus Pen Signal Synchronization

Solution Overview

Problem

Existing touch panel systems face challenges in integrating touch detection capabilities into display panels without adding extra electrodes and sensors, which complicates the design and can interfere with the display panel's driving mechanisms, especially when the touch panel is integrated inside the display panel with a pixel array.

Innovation Solution

An input system with an in-cell type touchscreen structure that uses a conductive tip pen with a switching unit, receiving unit, driving unit, and signal processing unit to synchronize the pen driving signal with the touchscreen driving signal, allowing touch detection without additional electrodes, and includes a pressure sensor for enhanced sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional electrodes and sensors are added to enable stylus pen recognition, then input precision is improved, but device complexity increases

Engineering Contradiction:

Improveinput precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The touchscreen electrodes serve dual purposes: they function as both display pixels and touch sensing electrodes. The same electrode structure is used for both displaying images and detecting touch inputs, eliminating the need for separate touch electrodes and reducing overall device complexity while maintaining input precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The display panel and touch panel are merged into a single integrated structure. The touchscreen is formed within the display panel itself, combining the pixel array and touch detection functions into one unified component, thereby reducing the number of separate parts and simplifying the overall device architecture.

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If additional electrodes and sensors are added to enable stylus pen recognition, then input precision is improved, but manufacturing cost increases

Engineering Contradiction:

Improveinput precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The touchscreen electrodes serve dual purposes: they function as both display pixels and touch sensing electrodes. The same electrode structure is used for both displaying images and detecting touch inputs, eliminating the need for separate touch electrodes and reducing overall device complexity while maintaining input precision.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The display panel and touch panel are merged into a single integrated structure. The touchscreen is formed within the display panel itself, combining the pixel array and touch detection functions into one unified component, thereby reducing the number of separate parts and simplifying the overall device architecture.

Inventive Principle:

Principle #5Merging (Combining)

3Length of moving object

If touch panel is integrated inside display panel with pixel array, then device thickness is reduced, but adding extra electrode becomes impractical

Engineering Contradiction:

Improvedevice thicknessVSAvoidelectrode integration complexity

Core Design Contradiction:

Length of moving objectVSDevice complexity

Solution Approach 1:

The display panel and touch panel are merged into a single integrated structure. The touchscreen is formed within the display panel itself, combining the pixel array and touch detection functions into one unified component, thereby reducing the number of separate parts and simplifying the overall device architecture.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The touchscreen electrodes serve dual purposes: they function as both display pixels and touch sensing electrodes. The same electrode structure is used for both displaying images and detecting touch inputs, eliminating the need for separate touch electrodes and reducing overall device complexity while maintaining input precision.

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 touch detection accuracy and sensitivity without adding separate electrodes or sensors, maintaining the display panel's thickness and weight, and ensuring seamless integration with the display panel's driving mechanisms.

Implementation Method 1

When the conductive tip contacts or approaches the display panel, the conductive tip is coupled to a selected one of the touch detection electrodes... so the conductive tip receives the touchscreen driving signal

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Data Source

PatentUS10698506B2Input system and method for detecting touch using the same

Publication Date: 2020.06.30 LG DISPLAY CO LTD

AI summary

An input system includes an input pen for interfacing with a touchscreen of a display panel. The input pen includes a conductive tip. A switching unit of the pen connects the conductive tip to a receiving unit and a driving unit. The receiving unit receives touchscreen driving signals from the touchscreen through the conductive tip. The driving unit generates pen driving signals transferred to the touchscreen through the conductive tip. The input pen also include a signal processing unit to calibrate timing of the pen driving signal by synchronizing the pen driving signal with the touchscreen driving signal. To enable touch detection, the conductive tip is positioned to contact or approach the touchscreen, the touchscreen driving signal is received from the touchscreen via the conductive tip. The pen driving signal is generated and transferred to the touchscreen via the conductive tip.