Integrated Touch Sensing Display with Capacitive Coupling

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Solution Overview

Problem

Existing position sensing displays require separate touch panels that can introduce manufacturing complexities, increase costs, and affect optical performance due to additional surfaces that may cause reflections and trap dust or particles.

Innovation Solution

An active matrix liquid crystal display integrates sense circuits with the display by using a transparent front panel with sense electrodes and a rear active substrate, where sense signals are capacitively coupled through coupling electrodes, eliminating the need for ohmic contacts and separate touch panels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate touch panels are used for position sensing, then touch sensing functionality is achieved, but manufacturing complexity increases and costs increase

Engineering Contradiction:

Improvetouch sensing functionalityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the touch sensing function with the display structure by integrating sense electrodes directly into the display's front panel and coupling electrodes into the rear panel. This merging eliminates the need for separate touch panels while achieving the same touch sensing functionality, thereby reducing manufacturing complexity and costs.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The display structure is designed to serve multiple functions: the front panel with sense electrodes provides both display functionality and touch sensing capability, while the rear panel with coupling electrodes provides both structural support and signal coupling. This multi-functionality reduces the need for additional separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If separate touch panels are used for position sensing, then touch sensing functionality is achieved, but costs increase

Engineering Contradiction:

Improvetouch sensing functionalityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

By merging the touch sensing function into the existing display structure through integrated sense and coupling electrodes, the patent eliminates the need to manufacture and assemble separate touch panels, thereby reducing overall manufacturing costs while maintaining touch sensing functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The display components are designed to perform multiple functions simultaneously - the front panel serves as both the display interface and the touch sensing interface, while the rear panel provides both structural support and electrical coupling, reducing the total component count and manufacturing cost.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If separate touch panels are used for position sensing, then touch sensing functionality is achieved, but optical performance deteriorates due to additional surfaces causing reflections and particle trapping

Engineering Contradiction:

Improvetouch sensing functionalityVSAvoidreflections and particle trapping

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

By integrating the touch sensing electrodes directly into the display's existing glass panels rather than adding separate touch panels, the patent eliminates additional air-glass interfaces that would cause reflections and trap particles. The sense electrodes are formed on the inner surface of the front panel and coupling electrodes on the rear panel, maintaining a clean optical path.

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 integration simplifies manufacturing, reduces costs, improves yield, and enhances optical performance by eliminating additional surfaces that can cause reflections and particle trapping, while enabling accurate touch sensing without the reliability issues associated with ohmic contacts.

Implementation Method 1

coupling capacitors capacitively coupling the sense electrodes to the respective sense circuits for coupling sense signals from the sense electrodes to the sense circuits

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

a common electrode for cooperating with a rear active substrate for driving the liquid crystal

Methodology Applied

Scientific EffectLiquid crystal effect: Liquid Crystals

Data Source

PatentUS8300021B2Position sensing display

Publication Date: 2012.10.30 INNOLUX CORP

AI summary

A position sensing display integrates a touch sensor with an active matrix LCD panel. X sense electrodes and y sense electrodes in respective layers on a front panel are coupled capacitatively to respective sense circuits on active rear panel. A common electrode is driven, and the resulting signal on the x-sense electrodes and y sense electrodes is measured by the respective sense circuits. Changes in the resulting signal when sensed object approaches are measured to locate the sensed object.