Filler Mounting for Ultrasonic Sensor Under Display

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Solution Overview

Problem

Ultrasonic sensors used in electronic devices, such as smartphones, often experience reduced recognition performance due to air gaps formed by liquid adhesives or contraction issues, leading to nonuniform attachment surfaces and degraded display visibility.

Innovation Solution

A mounting structure using a filler on the rear surface of the display to eliminate or reduce air gaps between the ultrasonic sensor and the display, combined with the addition of an acoustic lens to enhance signal transmission and recognition performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If liquid adhesive is used to attach the ultrasonic sensor, then the sensor can be mounted on the display, but air gaps are formed and the attachment surface becomes nonuniform

Engineering Contradiction:
Improvesensor mountingVSAvoidattachment surface uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent changes the physical state of the adhesive from liquid to solid by introducing a filler material (such as epoxy resin or silicone rubber) that transforms the adhesive properties. This eliminates air gaps and ensures uniform attachment surface while maintaining ease of mounting.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by combining the adhesive with filler particles or using a composite adhesive structure. This composite approach fills voids and air gaps that pure liquid adhesive cannot eliminate, achieving both easy mounting and surface uniformity.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If liquid adhesive is used to attach the ultrasonic sensor, then the sensor can be mounted on the display, but display visibility is degraded

Engineering Contradiction:
Improvesensor mountingVSAvoiddisplay visibility
Core Design Contradiction:
Ease of manufactureVSIllumination intensity

Solution Approach 1:

The patent modifies the adhesive parameters by using a filler-based adhesive that cures to a solid state, eliminating the liquid adhesive layer that causes light scattering. This improves display visibility while maintaining the mounting function.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent extracts or removes the harmful liquid adhesive layer that degrades visibility by replacing it with a solid filler-based adhesive that does not scatter light, thus eliminating the visibility problem while keeping the sensor mounted.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If acoustic lens is added to the ultrasonic sensor, then signal transmission is improved, but device complexity increases

Engineering Contradiction:
Improvefingerprint recognition performanceVSAvoidsensor structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The acoustic lens is integrated into the existing sensor structure, serving multiple functions: improving ultrasonic signal transmission, protecting the sensor surface, and potentially serving as part of the sealing structure. This multi-functionality reduces the impact of added complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the acoustic lens with the sensor assembly, combining multiple components into an integrated unit. This reduces the number of separate parts and simplifies the overall device structure while maintaining the performance benefits of the acoustic lens.

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 solution improves the visibility of the display and enhances fingerprint recognition performance by minimizing air gaps and optimizing the acoustic signal transmission, resulting in improved sensor performance.

Implementation Method 1

an acoustic lens disposed on the ultrasonic sensor to be able to improve transmission of an ultrasonic signal

Methodology Applied
Scientific EffectAcoustic lens: Acoustic Lens

Data Source

PatentEP3718289B1Electronic device including filler for filling a space between biological sensor disposed under a display and the display
Publication Date: 2021.12.29 SAMSUNG ELECTRONICS CO LTD
  • EP3718289B1 patent drawingFigure 1~2
  • EP3718289B1 patent drawingFigure 3
  • EP3718289B1 patent drawingFigure 4~5

AI summary

An electronic device includes: a transparent member comprising a transparent material; a display panel disposed under the transparent member; a shock absorption sheet disposed under the display panel, and having an opening formed in a region thereof; a biological sensor disposed to face the display panel, and disposed in at least a portion of the opening; a filler material filling at least some space in the opening formed between the biological sensor and the display panel; and a seal disposed between the biological sensor and the shock absorption member and configured to prevent the filler from being discharged outside the opening.