Touch Input Apparatus With Slit Ground Plate

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Solution Overview

Problem

Existing touch input systems experience signal loss and decreased sensitivity due to eddy currents when using electromagnetic signals, particularly when interacting with metal surfaces, leading to reduced performance in recognizing user inputs.

Innovation Solution

The input apparatus incorporates a conductivity tip with a coil and a ground plate that forms an open loop or includes slits to minimize eddy losses, allowing for efficient signal transfer and increased touch sensitivity without the need for additional power sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a closed loop metal shield is used to protect the electromagnetic signal, then electromagnetic shielding is improved, but eddy current loss increases and signal strength decreases

Engineering Contradiction:
Improveelectromagnetic shieldingVSAvoideddy current loss
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The ground plate is designed with slits that divide the continuous metal structure into segmented regions. This segmentation interrupts the formation of closed-loop eddy current paths while maintaining the ground plate's electromagnetic shielding function, thereby reducing eddy current loss and improving signal strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The harmful eddy current paths are extracted or removed from the ground plate structure by introducing slits. This allows the ground plate to retain its shielding function while eliminating the continuous conductive loops that cause energy loss through eddy currents.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If electromagnetic signal strength is increased to improve recognition, then signal recognition is improved, but energy consumption increases

Engineering Contradiction:
Improvesignal recognitionVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The slits in the ground plate convert what would be harmful eddy current paths into beneficial structures that redirect electromagnetic signals. By preventing energy-wasting eddy currents, more energy is available for productive signal transmission, improving recognition without increasing overall energy consumption.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The ground plate's electrical conductivity distribution is changed by introducing slits, creating regions of high and low conductivity. This parameter change optimizes the electromagnetic field distribution, enhancing signal recognition efficiency while reducing energy loss.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a continuous ground plate is used to provide grounding, then grounding effectiveness is improved, but eddy current formation is enabled

Engineering Contradiction:
Improvegrounding effectivenessVSAvoideddy current formation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The continuous ground plate is segmented by slits into multiple isolated conductive regions. This segmentation maintains grounding effectiveness for each local region while preventing the formation of continuous closed loops that would enable harmful eddy currents.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The slits create an asymmetric structure in the ground plate that disrupts the symmetry required for eddy current formation. The asymmetric slit patterns break the continuous conductive paths while maintaining adequate grounding coverage through distributed ground contacts.

Inventive Principle:
Principle #4Asymmetry

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 enhances touch sensitivity and reduces energy consumption by minimizing eddy losses, enabling more accurate and efficient electromagnetic signal transfer between the input apparatus and the display device.

Implementation Method 1

The input apparatus transmits the electromagnetic signal to the display device by using an electromagnetic signal generating circuit

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The electromagnetic signal may form an eddy current in a metal plate, and may be decreased in the form of an eddy loss

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Data Source

PatentEP2860613B1Touch input apparatus
Publication Date: 2019.03.13 LG DISPLAY CO LTD
  • EP2860613B1 patent drawingFigure 1
  • EP2860613B1 patent drawingFigure 2
  • EP2860613B1 patent drawingFigure 3

AI summary

The present invention provides an input apparatus which can include a conductivity tip (512), a coil (522) electrically connected to the tip (512), and a ground plate (536) electrically connected to the coil (522) and forming an open loop in a circumference direction of the coil (522).