In-Cell Touch LCD Merging Sensing Lines With Display Substrates

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Solution Overview

Problem

Conventional touch-sensitive LCD devices are thick and heavy due to multiple layers, including touch panels and adhesive layers, which reduces light transmittance and display quality.

Innovation Solution

An in-cell touch-sensitive LCD device design integrates touch sensing functionality within the display by using a first and second substrate with a liquid crystal layer, first and second sensing lines, and conductive layers electrically isolated by a gap, where a spacer connects these layers upon external pressure to transmit touch signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional touch-sensitive panel with multiple layers (upper substrate, lower substrate, transparent conductive layers, spacer, adhesive layer) is used, then touch sensitivity is achieved, but the overall thickness and weight increase

Engineering Contradiction:

Improvetouch sensitivityVSAvoiddevice thickness

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent merges the touch-sensitive panel and display panel into a single integrated structure. The touch-sensitive functional layers (conductive layers, spacers) are formed directly on the display panel substrates, eliminating the need for a separate touch panel and its supporting adhesive layers. This integration maintains touch sensitivity while reducing overall device thickness.

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If multiple layers including adhesive layer are stacked to form touch-sensitive panel, then touch functionality is achieved, but the overall weight increases

Engineering Contradiction:

Improvetouch functionalityVSAvoiddevice weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent combines the touch-sensitive panel and display panel into one integrated device, eliminating redundant layers including the adhesive layer that bonds separate panels. By forming touch-sensitive conductive layers and spacers directly on the display panel substrates during the display panel manufacturing process, the patent removes unnecessary materials while preserving complete touch functionality.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If touch-sensitive panel and adhesive layer are added, then touch sensitivity is achieved, but light transmittance rate decreases

Engineering Contradiction:

Improvetouch sensitivityVSAvoidlight transmittance rate

Core Design Contradiction:

ReliabilityVSIllumination intensity

Solution Approach 1:

The patent integrates touch-sensitive functional layers within the display panel structure itself, eliminating the need for a separate touch panel and adhesive layer that would block light. The conductive layers and spacers are formed directly on the display panel substrates, minimizing additional light-blocking materials while maintaining touch sensitivity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses thin transparent conductive layers (such as ITO - indium tin oxide) for the touch-sensitive electrodes. These thin film structures provide the necessary electrical conductivity for touch sensing while minimizing light absorption and maintaining high light transmittance rates.

Inventive Principle:

Principle #30Flexible shells and thin films

4Adaptability or versatility

If conventional separate touch panel and display panel are used, then touch and display functions are achieved, but device complexity increases

Engineering Contradiction:

Improvetouch and display functionsVSAvoidnumber of layers

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the touch-sensitive panel and display panel into a single integrated device with unified substrate structures. The touch-sensitive conductive layers and spacers are formed directly on the display panel substrates during the display panel manufacturing process, eliminating the need for separate panel assemblies and reducing overall device complexity while maintaining both touch and display functions.

Inventive Principle:

Principle #5Merging (Combining)

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 design reduces device thickness, maintains brightness, and integrates touch panel and display panel functions, enhancing user interaction while preserving display quality.

Implementation Method 1

a liquid crystal layer disposed between the first substrate and the second substrate

Methodology Applied

Scientific EffectLiquid crystal effect: Liquid Crystals

Implementation Method 2

The spacer is electrically connected to the first conductive layer and the second conductive layer in response to an external pressure

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentUS8279361B2Touch-sensitive liquid crystal display device

Publication Date: 2012.10.02 INNOLUX CORP

AI summary

A in-cell touch-sensitive liquid crystal display device (LCD) includes a first substrate, a second substrate opposite to the first substrate, a liquid crystal layer disposed between the first substrate and the second substrate, a first sensing line and a second sensing line disposed on the second substrate, a first conductive layer and a second conductive layer electrically connected to the first sensing line and the second sensing line, respectively, and electrically isolated from each other by a gap existing therebetween. The in-cell touch-sensitive LCD device further includes a spacer disposed on the first substrate and corresponding to the gap. The spacer is electrically connected to the first conductive layer and the second conductive layer in response to an external pressure.