Digitizer Absorber Sheet Composition for Magnetic Interference Control

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Solution Overview

Problem

Existing electronic devices with digitizers face challenges in maintaining accurate position detection of digital pens due to interference from external magnetic fields and metal components, which can lead to reduced sensitivity and accuracy of the digitizer.

Innovation Solution

The electronic device incorporates an absorber sheet with a specific composition of first particles (iron, silicon, and aluminum) and second particles (iron and silicon), with a ratio of second particles to first particles of 7:3 or higher, positioned under the digitizer. This configuration enhances the sensitivity of the digitizer and reduces electromagnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a digitizer is positioned under the display to enable digital pen input detection, then the electronic device can receive various inputs from users, but external magnetic fields and metal components cause interference that reduces detection accuracy and sensitivity

Engineering Contradiction:

Improvedigital pen input detection capabilityVSAvoidposition detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

An absorber sheet is introduced as an intermediary layer positioned between the metal components and the digitizer. This absorber sheet acts as a mediator that absorbs and attenuates magnetic field interference before it reaches the digitizer, thereby protecting the position detection system from external magnetic field interference while maintaining the overall structure's functionality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful magnetic field interference from metal components into a beneficial shielding effect by strategically positioning absorber sheets and metal sheets. The metal components that originally caused interference are repositioned and combined with absorber materials to create an electromagnetic shielding structure that protects the digitizer while maintaining structural integrity

Inventive Principle:

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

2Strength

If metal components are used in the electronic device structure, then the device gains structural strength and durability, but these metal components generate eddy currents and inductance drop that interfere with digitizer sensitivity

Engineering Contradiction:

Improvestructural strengthVSAvoidelectromagnetic interference

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The electromagnetic shielding structure is segmented into multiple functional layers: absorber sheets positioned at specific locations to absorb magnetic field interference, and metal sheets positioned to provide structural strength while minimizing interference. This segmentation allows each layer to perform its specific function optimally without compromising the other

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs composite electromagnetic shielding structures combining absorber materials (such as ferrite particles embedded in polymer matrices) with metal sheets. This composite approach leverages the magnetic field absorption properties of the absorber materials and the structural strength and electromagnetic shielding properties of the metal sheets, achieving both mechanical integrity and electromagnetic compatibility

Inventive Principle:

Principle #40Composite materials

3Reliability

If the absorber sheet uses a high ratio of second particles (iron and silicon) to first particles (iron, silicon, and aluminum), then inductance drop and eddy current generation are reduced, but the manufacturing complexity increases due to precise composition requirements

Engineering Contradiction:

Improvedigitizer sensitivityVSAvoidabsorber sheet fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent specifies precise compositional parameters for the absorber sheet, including the particle size distribution (D10, D50, D90 values) and the ratio of different particle types (first particles containing aluminum, second particles without aluminum). By controlling these parameters within defined ranges, the invention achieves optimal electromagnetic interference reduction while providing clear manufacturing guidelines to manage complexity

Inventive Principle:

Principle #35Parameter changes

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

The use of the absorber sheet with a high ratio of second particles to first particles improves the digitizer's sensitivity and accuracy by reducing inductance drop and eddy current generation, thereby enhancing the overall performance of the electronic device in detecting digital pen inputs.

Implementation Method 1

an absorber sheet positioned under the digitizer... The absorber sheet may include first particles including iron, silicon, and aluminum, and second particles including iron and silicon

Methodology Applied

Scientific EffectElectromagnetic absorption: Absorption (EM radiation)

Implementation Method 2

The use of the absorber sheet with a high ratio of second particles to first particles improves the digitizer's sensitivity and accuracy by reducing inductance drop and eddy current generation

Methodology Applied

Scientific EffectElectromagnetic interference reduction: Eddy Currents

Data Source

PatentUS20250119487A1Electronic device including digitizer

Publication Date: 2025.04.10 SAMSUNG ELECTRONICS CO LTD

AI summary

An electronic device may be provided. The electronic device may comprise: a housing; a display; a digitizer disposed under the display; an absorber sheet disposed under the digitizer; and a metal sheet disposed under the absorber sheet. The absorber sheet may comprise: first particles containing iron, silicon, and aluminum; and second particles containing iron and silicon. The ratio of the second particles to the first particles may be 7:3 or greater.