Under-Display Infrared Illumination Layout for Optical Sensors

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Solution Overview

Problem

Optical sensors in devices like smartphones face significant light loss due to the limited transparency of displays, as illumination units are placed behind the display, leading to inefficiencies in power consumption, heating, and potential damage.

Innovation Solution

Incorporating second light-emitting elements, such as micro LEDs or VCSELs, within the display device to emit infrared light for scene illumination, allowing the display device to be positioned between the optical sensor and the scene, thereby reducing light transmission through the display and enhancing power efficiency and reducing heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If illumination units are placed behind the display, then the display structure is simplified, but light loss increases due to limited display transparency

Engineering Contradiction:

Improvedisplay structureVSAvoidlight loss

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent extracts the infrared illumination function from the traditional behind-display illumination unit and places it directly in front of the optical sensor. This separation allows the illumination light to travel a shorter path through the display, reducing light loss while maintaining structural simplicity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the spatial arrangement by moving the illumination unit from a single dimension (behind the display) to a different spatial position (in front of the optical sensor, adjacent to the display). This dimensional change reduces the light path through the display while maintaining integration.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Device complexity

If illumination units are placed behind the display, then integration is improved, but power consumption increases due to light loss

Engineering Contradiction:

ImproveintegrationVSAvoidpower consumption

Core Design Contradiction:

Device complexityVSUse of energy by moving object

Solution Approach 1:

The illumination function is extracted from the behind-display position and relocated to an adjacent position near the optical sensor. This extraction reduces the light path through the display, improving illumination efficiency and reducing power consumption while maintaining integration benefits.

Inventive Principle:

Principle #2Taking out (Extraction)

3Volume of moving object

If illumination units are placed behind the display, then structural compactness is improved, but heating increases due to light loss

Engineering Contradiction:

Improvestructural compactnessVSAvoidheating

Core Design Contradiction:

Volume of moving objectVSTemperature

Solution Approach 1:

The illumination unit is extracted from the compact behind-display arrangement and positioned adjacent to the optical sensor. This extraction reduces the light path through the display, minimizing energy loss and reducing heat generation while maintaining structural compactness through integrated positioning.

Inventive Principle:

Principle #2Taking out (Extraction)

4Ease of manufacture

If illumination units are placed behind the display, then manufacturing simplicity is improved, but risk of display damage increases

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoiddisplay damage risk

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The illumination unit is extracted from the behind-display position and placed adjacent to the optical sensor. This extraction eliminates the need for light to pass through the display from the back, reducing the risk of display damage while maintaining manufacturing simplicity through integrated module assembly.

Inventive Principle:

Principle #2Taking out (Extraction)

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 reduces power consumption, minimizes display damage, and improves illumination efficiency by embedding infrared light-emitting elements within the display, ensuring effective operation of optical sensors.

Implementation Method 1

at least one second light-emitting element configured to emit infrared light for illuminating a scene in front of the front side of the display device

Methodology Applied

Scientific EffectInfrared light emission: Light Emitting Diode

Implementation Method 2

at least one optical sensor configured to measure reflected infrared light from the scene

Methodology Applied

Scientific EffectInfrared detection: Photoelectric Effect

Data Source

PatentUS12431470B2Display device and electronic device including the display device

Publication Date: 2025.09.30 INFINEON TECHNOLOGIES AG

AI summary

A display device is provided. The display device includes a plurality of first light-emitting elements configured to emit light for displaying an optical image on a front side of the display device. Additionally, the display device includes at least one second light-emitting element configured to emit infrared light for illuminating a scene in front of the front side of the display device.