Digitizer Surface Roughness for Display Visibility

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Solution Overview

Problem

Existing electronic apparatuses face challenges in maintaining improved visibility and reliability due to uneven surfaces within the digitizer layer, which can cause visual disturbances and electrical interference when light is transmitted through the display module.

Innovation Solution

The electronic apparatus incorporates a digitizer with a photosensitive resin layer having two opposing surfaces, where the first surface is relatively flat and smoother, and the second surface is more rough, with a shielding layer on the rough surface, and sensing coils embedded within the resin layer to sense external inputs, while maintaining a slim design without a separate adhesive layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a digitizer with sensing coils is disposed under the display panel, then sensing function is provided, but uneven surfaces and visual disturbances occur due to light transmission through the display module

Engineering Contradiction:

Improvesensing functionVSAvoidvisual disturbances

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by creating different surface roughness characteristics at different locations of the digitizer. The first surface (facing display panel) has controlled roughness of 1-10 micrometers to minimize visual disturbances when light passes through, while the second surface (facing user) has higher roughness of 5-15 micrometers for adhesive bonding. This spatial differentiation of surface properties resolves the contradiction between providing sensing function and preventing visual disturbances.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If the first surface of the digitizer is made flat for improved visibility, then visual appearance is enhanced, but adhesive bonding strength is reduced

Engineering Contradiction:

ImprovevisibilityVSAvoidadhesive bonding strength

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent resolves this contradiction by applying different surface roughness values to different surfaces of the same digitizer component. The first surface has controlled roughness (1-10 micrometers) optimized for visual appearance and light transmission, while the second surface has higher roughness (5-15 micrometers) optimized for adhesive bonding strength. This allows each surface to be locally optimized for its specific function without compromising the other.

Inventive Principle:

Principle #3Local quality

3Reliability

If a separate adhesive layer is added to attach the shielding layer, then bonding reliability is improved, but device thickness increases

Engineering Contradiction:

Improvebonding reliabilityVSAvoiddevice thickness

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The patent merges the adhesive layer with the photosensitive resin layer that contains the sensing coils. The photosensitive resin layer serves dual functions: it embeds the sensing coils and provides adhesive bonding between the digitizer and display panel. This integration eliminates the need for a separate adhesive layer, maintaining bonding reliability while reducing overall device thickness and simplifying the structure.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The photosensitive resin layer is designed to perform multiple functions simultaneously: it acts as both the embedding medium for the sensing coils and the adhesive layer for bonding. This multi-functionality reduces the number of separate components needed, thereby reducing device thickness while maintaining or improving bonding reliability through optimized material properties.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 configuration enhances visibility by minimizing the visibility of uneven surfaces and improves reliability by reducing electrical interference, while allowing for efficient sensing of external inputs and maintaining a slim form factor.

Implementation Method 1

a plurality of sensing coils disposed inside the photosensitive resin layer

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a photosensitive resin layer including a first surface and a second surface opposite to the first surface

Methodology Applied

Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentUS11281346B2Electronic apparatus including display panel and digitizer

Publication Date: 2022.03.22 SAMSUNG DISPLAY CO LTD

AI summary

An electronic apparatus includes a window, a display panel disposed under the window, and a digitizer disposed under the display panel. The digitizer includes a photosensitive resin layer including a front surface and a rear surface opposite to the front surface, and a plurality of sensing coils disposed inside the photosensitive resin layer. The front surface is relatively flat compared with the rear surface.