Under-Display Image Sensor Foreign Object Detection

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Solution Overview

Problem

Electronic devices with touch screens face damage due to foreign objects attached to the screen, which can affect sensitivity and cause damage, especially in foldable screens that are prone to damage when folded with foreign objects present.

Innovation Solution

An apparatus with an image sensor below the screen captures detection images to identify foreign objects by comparing pixel brightness, allowing for real-time or periodic detection and prompting users to remove them, thereby preventing screen damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an image sensor is added below the screen to detect foreign objects, then foreign object detection capability is improved, but device complexity increases

Engineering Contradiction:
Improveforeign object detection capabilityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The image sensor below the screen is designed to serve multiple functions: it can detect foreign objects on the screen surface and also function as a fingerprint sensor for authentication. By making the sensor multi-functional, the patent avoids adding a separate dedicated foreign object detection sensor, thereby improving detection capability while minimizing the increase in device complexity

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

Solution Approach 2:

The existing image sensor structure below the screen is utilized for foreign object detection without requiring additional specialized components. The sensor leverages its inherent imaging capability to detect foreign objects by capturing light reflections or shadows, allowing the system to perform foreign object detection using already-present hardware resources

Inventive Principle:
Principle #25Self-service

2Speed

If the image sensor continuously captures detection images to detect foreign objects in real-time, then detection responsiveness is improved, but energy consumption increases

Engineering Contradiction:
Improvedetection responsivenessVSAvoidenergy consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

Instead of continuous real-time monitoring, the patent implements periodic detection by capturing detection images at specific intervals or under specific conditions (such as when the screen is touched or during idle periods). This periodic action maintains detection responsiveness for critical moments while significantly reducing overall energy consumption compared to continuous monitoring

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system performs preliminary detection by capturing detection images before actual screen usage or during setup phases, and also performs detection after screen operations. This preliminary and post-action detection approach ensures foreign objects are detected at critical moments without requiring constant continuous monitoring, thereby balancing responsiveness with energy efficiency

Inventive Principle:
Principle #10Preliminary action

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

Effectively detects and alerts users to foreign objects on the screen, reducing the risk of damage and improving the endurance and convenience of electronic devices, especially foldable screens.

Implementation Method 1

An image sensor arranged below the screen of the electronic device... acquire a detection image captured by an image sensor... detect whether a foreign object is attached on the screen based on the detection image

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3923037B1Foreign object detection method, foreign object detection device, and electronic apparatus
Publication Date: 2024.05.29 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP3923037B1 patent drawingFigure 1~3
  • EP3923037B1 patent drawingFigure 4~6
  • EP3923037B1 patent drawingFigure 7~9

AI summary

A foreign object detection method, a foreign object detection device, and an electronic apparatus. The method is used to detect whether a foreign object is present on a screen (32) of an electronic apparatus. An image sensor (33) is provided under the screen (32) of the electronic apparatus. The method comprises: acquiring a detection image captured by the image sensor (33); and detecting, according to the detection image, whether a foreign object is present on the screen (32). The method enables a user to ascertain whether a foreign object is present on a screen (32), such that the foreign object can be timely removed without damaging the screen (32).