Under-Display Illumination Using High-Transmissivity Regions

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Solution Overview

Problem

Existing display devices with under-display illumination units face inefficiencies due to limited transparency, leading to increased power consumption, heating, and potential damage from light absorption, as well as interference with camera functionality.

Innovation Solution

A display device with non-uniform transmissivity regions and an optical element to focus light through higher transparency areas, combined with control circuitry for selective illumination based on object detection, reducing power consumption and enhancing illumination efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the illumination unit is mounted under the display, then the device achieves full-screen display coverage, but the limited transparency of the display causes increased power consumption

Engineering Contradiction:
Improvedisplay coverage areaVSAvoidpower consumption of illumination unit
Core Design Contradiction:
Area of stationary objectVSUse of energy by moving object

Solution Approach 1:

The display is designed with non-uniform transmissivity, creating a first display region with higher transmissivity and a second display region with lower transmissivity. The optical element focuses illumination light specifically through the first display region, allowing the illumination unit to operate more efficiently by utilizing the higher transparency area, thereby reducing overall power consumption while maintaining full-screen display coverage.

Inventive Principle:
Principle #3Local quality

2Device complexity

If the illumination unit is mounted under the display, then the device achieves compact integration, but the absorbed light causes punctual heating that may cause aging effect on display pixels

Engineering Contradiction:
Improveintegration structureVSAvoidheating effect on display pixels
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

By creating a localized high-transmissivity region in the display and focusing illumination light through this specific area, the patent reduces light absorption and subsequent heating in the illuminated region. This localized approach minimizes thermal damage to display pixels while maintaining the compact integrated structure.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The optical element acts as an intermediary that directs and focuses illumination light through the high-transmissivity region of the display. This intermediary component enables the illumination unit to function effectively under the display while reducing harmful heating effects by controlling the light path through the most transparent area.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Area of stationary object

If the illumination unit is mounted under the display, then the device achieves space efficiency, but the heat causes punctual expansion of the display which contributes to glass fracture

Engineering Contradiction:
Improvedevice front surface utilizationVSAvoiddisplay glass integrity
Core Design Contradiction:
Area of stationary objectVSStrength

Solution Approach 1:

The patent creates a localized high-transmissivity region and focuses illumination through this area, reducing heat generation and subsequent thermal expansion in the illuminated region. This localized heat management approach prevents punctual expansion that could lead to glass fracture, while maintaining space-efficient device design.

Inventive Principle:
Principle #3Local quality

4Device complexity

If the illumination unit is mounted under the display, then the device achieves compact structure, but the light reflected by the display may further impair cameras located under the display

Engineering Contradiction:
Improvecomponent arrangementVSAvoidreflected light interference with camera
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

By focusing illumination light through a specific high-transmissivity region and controlling the illumination pattern, the patent reduces unwanted light reflection from the display. This localized illumination approach minimizes reflected light that could interfere with camera operations, while maintaining the compact integrated structure.

Inventive Principle:
Principle #3Local quality

5Illumination intensity

If the illumination unit operates with full backlight illumination, then the scene is evenly illuminated, but additional dark current/leakage current is generated

Engineering Contradiction:
Improvescene illumination uniformityVSAvoiddark current/leakage current
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent implements selective illumination by controlling individual illumination elements to illuminate only specific parts of the scene that likely contain objects of interest. This localized illumination approach reduces the need for full backlight illumination, thereby decreasing dark current and leakage current generation while maintaining effective scene illumination for object detection.

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

This approach reduces power consumption and minimizes display damage while improving illumination efficiency and object tracking accuracy.

Implementation Method 1

The at least one optical element is configured to focus the light emitted by the plurality of illumination elements through the first display region

Methodology Applied
Scientific EffectLight focusing: Focusing

Implementation Method 2

The display device comprises a first display region exhibiting a first transmissivity for the light emitted by the plurality of illumination elements and a second display region exhibiting a second transmissivity

Methodology Applied
Scientific EffectLight transmission: Refraction

Implementation Method 3

The optical sensor is configured to measure a fraction of the light emitted by the plurality of illumination elements that is reflected back from the scene

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4001989B1Electronic device and method for an electronic device
Publication Date: 2025.07.09 INFINEON TECHNOLOGIES AG
  • EP4001989B1 patent drawingFigure 1
  • EP4001989B1 patent drawingFigure 2
  • EP4001989B1 patent drawingFigure 3~4

AI summary

An electronic device is provided. The electronic device includes a display device comprising a plurality of light-emitting elements for displaying an optical image on a front side of the display device. Further, the electronic device includes at least one illumination element configured to emit light for illuminating a scene in front of the front side of the display device. The display device is arranged between the at least one illumination element and the scene. The display device comprises a first display region exhibiting a first transmissivity for the light emitted by the at least one illumination element and a second display region exhibiting a second transmissivity for the light emitted by the at least one illumination element. The first transmissivity is higher than the second transmissivity. The electronic device additionally includes at least one optical element arranged between the at least one illumination element and the display device. The at least one optical element is configured to focus the light emitted by the at least one illumination element through the first display region.