Liquid Crystal Display Touch Sensing Using Source and Capacitance Lines

Solution Overview

Problem

Existing liquid crystal display devices with touch sensing functions face challenges in integrating detection elements effectively, leading to increased costs and complexity, while maintaining the display quality and sensitivity of touch detection.

Innovation Solution

The liquid crystal display device incorporates the source line and capacitance line as detection elements, using them to detect changes in electrostatic capacitance between the pixel electrodes and the counter electrode, eliminating the need for additional detection elements and allowing for simultaneous image display and touch detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional detection elements are added to the liquid crystal display device, then touch detection sensitivity is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvetouch detection sensitivityVSAvoidstructure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The source line and capacitance line, originally designed solely for driving liquid crystal pixels, are made to serve dual functions: continuing to drive the liquid crystal while simultaneously acting as detection elements for touch sensing. This multi-functionality eliminates the need for separate detection electrodes, reducing structural complexity while maintaining touch detection capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The existing source line and capacitance line structure serves itself by performing both driving and detection functions. The same conductive lines that control the liquid crystal display also detect touch input, allowing the system to utilize its existing components for additional functionality without requiring external additions

Inventive Principle:

Principle #25Self-service

2Measurement precision

If additional detection elements are added to the liquid crystal display device, then touch detection sensitivity is improved, but manufacturing cost increases

Engineering Contradiction:

Improvetouch detection sensitivityVSAvoidmanufacturing cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The source line and capacitance line, originally designed solely for driving liquid crystal pixels, are made to serve dual functions: continuing to drive the liquid crystal while simultaneously acting as detection elements for touch sensing. This multi-functionality eliminates the need for separate detection electrodes, reducing structural complexity while maintaining touch detection capability

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The existing source line and capacitance line structure serves itself by performing both driving and detection functions. The same conductive lines that control the liquid crystal display also detect touch input, allowing the system to utilize its existing components for additional functionality without requiring external additions

Inventive Principle:

Principle #25Self-service

3Adaptability or versatility

If detection elements are integrated between substrates, then touch detection function is achieved, but display quality may be compromised

Engineering Contradiction:

Improvetouch detection functionVSAvoiddisplay quality

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The source line and capacitance line, originally designed solely for driving liquid crystal pixels, are made to serve dual functions: continuing to drive the liquid crystal while simultaneously acting as detection elements for touch sensing. This multi-functionality eliminates the need for separate detection electrodes, reducing structural complexity while maintaining touch detection capability

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 configuration enables a cost-effective and miniaturized liquid crystal display device with enhanced detection sensitivity, as it utilizes existing driver IC chip components for both image signal writing and touch detection, without requiring additional external elements.

Implementation Method 1

a liquid crystal layer (LQ) held between the first and second substrates

Methodology Applied

Scientific EffectLiquid crystal phase change: Phase Change

Implementation Method 2

a detection circuit to detect change of electrostatic capacitance between the first and second detection elements

Methodology Applied

Scientific EffectElectrostatic capacitance: Capacitance

Data Source

PatentUS8643796B2Liquid crystal display device

Publication Date: 2014.02.04 MAGNOLIA WHITE CORP

AI summary

In one embodiment, a liquid crystal display device having a plurality of pixels includes a first substrate having an insulating substrate, a first detection element extending in a first direction above the insulating substrate, a second detection element extending in a second direction crossing the first direction and an insulating film provided between the first and second detection circuits. A second substrate is arranged opposing to the first substrate so as to hold a liquid crystal layer therebetween. A detection circuit is provided on the first substrate to detect change of electrostatic capacitance between the first and second detection elements. At least one of the first and second detection elements is an element required for operating the liquid crystal layer.