Integrated Touch Sensor Layer in Liquid Crystal Display

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Solution Overview

Problem

Conventional liquid crystal displays with integrated touch panels suffer from increased weight, thickness, and decreased image quality due to external touch panels, which also raise manufacturing costs and degrade luminance and contrast ratio.

Innovation Solution

A liquid crystal display design incorporating a touch sensor layer on one substrate with a bridge wire and insulating layer, and a conductive color filter layer on the other substrate, allowing for integrated touch functionality without additional substrates or films, thereby reducing thickness and weight while enhancing light transmittance and reducing noise interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an external touch panel is attached to the liquid crystal display, then touch functionality is achieved, but weight and thickness increase

Engineering Contradiction:

Improvetouch functionalityVSAvoidweight

Core Design Contradiction:

Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The touch sensor layer is integrated directly into the liquid crystal display structure by forming transparent electrodes on the same substrate as the color filter layer, merging two previously separate components (touch panel and LCD) into a single integrated device, thereby eliminating the need for an external touch panel attachment

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If an external touch panel is attached to the liquid crystal display, then touch functionality is achieved, but thickness increases

Engineering Contradiction:

Improvetouch functionalityVSAvoidthickness

Core Design Contradiction:

Adaptability or versatilityVSLength of stationary object

Solution Approach 1:

The touch sensor layer and color filter layer are formed on the same substrate, merging multiple functional layers into a single integrated structure, thereby reducing the overall thickness compared to stacking separate touch panel and LCD assemblies

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The invention transitions from a three-dimensional stacked structure (separate touch panel attached to LCD) to a two-dimensional integrated structure (touch sensor and color filter on the same substrate plane), effectively reducing the z-direction thickness

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If an external touch panel is attached to the liquid crystal display, then touch functionality is achieved, but luminance and contrast ratio deteriorate

Engineering Contradiction:

Improvetouch functionalityVSAvoidluminance

Core Design Contradiction:

Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The touch sensor layer uses transparent electrodes with optimized local transparency properties, allowing light to pass through the touch sensing regions while maintaining display quality, whereas traditional external touch panels use opaque or less transparent materials that block light

Inventive Principle:

Principle #3Local quality

4Adaptability or versatility

If an external touch panel is attached to the liquid crystal display, then touch functionality is achieved, but manufacturing cost increases

Engineering Contradiction:

Improvetouch functionalityVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The touch sensor layer and color filter layer are manufactured together in the same production process on the same substrate, eliminating the need for separate manufacturing and assembly steps for external touch panels, thereby reducing overall manufacturing cost

Inventive Principle:

Principle #5Merging (Combining)

5Reliability

If a bridge wire and insulating layer are added to the touch sensor layer, then electrical connection and insulation are improved, but device complexity increases

Engineering Contradiction:

Improveelectrical connectionVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The insulating layer serves multiple functions simultaneously: it provides electrical insulation between the bridge wire and first electrode, supports the bridge wire structure, and maintains the integrity of the transparent electrode pattern, thereby reducing the need for additional separate insulating components

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8289457B2Liquid crystal display including touch sensor layer and manufacturing method thereof

Publication Date: 2012.10.16 SAMSUNG DISPLAY CO LTD

AI summary

A liquid crystal display includes a first substrate, a second substrate having a first surface and a second surface facing the first substrate, a liquid crystal layer between the first and second substrates, and a touch sensor layer on the first surface. The touch sensor layer includes a first electrode in a first direction on the first surface, a second electrode in a second direction crossing the first direction on the first surface and including first and second portions that are separated by the first electrode, a bridge wire including first and second contacts on the first surface. The first contact is electrically connected to the first portion of the second electrode, and the second contact is electrically connected to the second portion of the second electrode. An insulating layer insulates the bridge wire from the first electrode and exposes the first contact and the second contact.