Biometric Sensor Fixing via Dual Adhesive Segmentation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing electronic devices face challenges in stably fixing biometric sensors on the rear surface of displays without damaging the display and maintaining visual quality, as the display area with the biometric sensor appears different from other areas.

Innovation Solution

A method involving a first fixing member hardened at a specified temperature and a second fixing member hardened by UV light is used to securely attach the biometric sensor to the display, ensuring the sensor is fixed without damaging the display and maintaining its visual integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a biometric sensor is attached to the rear surface of the display using conventional fixing methods, then the sensor can be fixed to the display, but the display area with the sensor appears different from other areas and may be damaged

Engineering Contradiction:
Improvefixing stabilityVSAvoidvisual quality
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The fixing process is divided into two stages: a first fixing member is applied to the sensor and partially cured, then a second fixing member is applied to the periphery and fully cured. This segmentation allows the sensor area to be fixed without fully saturating the adhesive, preventing visual defects while ensuring structural stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the display are treated differently: the sensor area uses a first fixing member with controlled adhesion, while the periphery uses a second fixing member for full fixation. This local differentiation ensures the sensor area maintains visual quality while still achieving reliable fixation through the combined fixing members.

Inventive Principle:
Principle #3Local quality

2Reliability

If the biometric sensor is fixed firmly to the display, then fixing stability is improved, but the display may be damaged or visual quality deteriorates

Engineering Contradiction:
Improvefixing stabilityVSAvoiddisplay damage risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The adhesive fixing is segmented into two members with different curing characteristics. The first fixing member provides initial fixation without full curing, reducing stress on the display, while the second fixing member provides peripheral support. This segmentation prevents excessive adhesive saturation that could damage the display.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first fixing member acts as an intermediary that provides temporary fixation and distributes stress, preventing direct excessive adhesion forces from damaging the display. It serves as a buffer between the sensor and the fully cured second fixing member, protecting the display while ensuring stable fixation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional adhesive fixing is used for the biometric sensor, then the sensor can be attached, but the adhesive may be visible and affect visual quality

Engineering Contradiction:
Improvevisual qualityVSAvoidfixing stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The adhesive system is segmented into two members: the first fixing member is applied sparsely to the sensor and partially cured to minimize visibility, while the second fixing member is applied to the periphery and fully cured for structural integrity. This segmentation allows the adhesive to provide stable fixation while remaining visually minimal in the sensor area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different adhesive characteristics are applied to different locations: the first fixing member uses controlled adhesion properties in the sensor area to prevent visibility, while the second fixing member uses full adhesion properties at the periphery for structural support. This local quality differentiation achieves both visual quality and fixing stability.

Inventive Principle:
Principle #3Local quality

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 method allows for stable fixation of biometric sensors on the rear surface of displays without breaking or modifying the display, improving visual quality by making the sensor area visually indistinguishable from the surrounding display area.

Implementation Method 1

a first fixing member interposed between the partial area of the second surface and the biometric sensor such that the sensing surface is attached to the partial area of the second surface, and hardened at a specified temperature

Methodology Applied
Scientific EffectHeat hardening:

Implementation Method 2

a second fixing member attached to at least a portion of the side surface and at least a portion of a peripheral area adjacent to the partial area of the second surface and hardened by light of a specified wavelength

Methodology Applied
Scientific EffectUV light hardening: Photopolymerisation

Data Source

PatentEP3940504B1Electronic device including multiple fixing members to fix biometric sensor to display and method for manufacturing the same
Publication Date: 2024.08.28 SAMSUNG ELECTRONICS CO LTD
  • EP3940504B1 patent drawingFigure 1
  • EP3940504B1 patent drawingFigure 2
  • EP3940504B1 patent drawingFigure 3

AI summary

An electronic device includes a display including a first surface facing a first direction to output display information and a second surface facing a second direction opposite the first direction, a biometric sensor including a sensing surface disposed to face a partial area of the second surface of the display and a side surface formed in a lateral direction, a first fixing member interposed between the partial area of the second surface and the biometric sensor such that the sensing surface is attached to the partial area of the second surface, and hardened at a specified temperature, and a second fixing member attached to at least a portion of the side surface and at least a portion of a peripheral area adjacent to the partial area of the second surface and hardened by light of a specified wavelength.