Under-Display Illuminance Sensor for Accurate Ambient Light Detection

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Solution Overview

Problem

The placement of illuminance sensors in electronic devices, such as smartphones, is limited by interference from display light emission, making it difficult to obtain accurate ambient light measurements, and there is a need to compensate for the deterioration of display brightness over time.

Innovation Solution

Mounting the illuminance sensor under the display in the screen area, allowing it to detect external ambient light while minimizing the influence of display light emission, and using detection data to adjust the display's brightness and compensate for subpixel deterioration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the illuminance sensor is mounted in the non-display area surrounding the screen, then the sensor can receive ambient light, but the position of the sensor is limited and interference with other parts (front camera, speaker) occurs

Engineering Contradiction:
Improveambient light measurement accuracyVSAvoidsensor positioning constraints
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The illuminance sensor is merged with the display structure by mounting it on the rear surface of the display assembly, specifically in the screen area. This integration allows the sensor to be positioned without occupying additional space in the non-display area, eliminating positioning constraints and interference with other components while maintaining ambient light detection capability.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If the illuminance sensor is mounted in the screen area of the display, then mounting freedom is increased, but the sensor cannot present exact measurement due to influence by display light emission

Engineering Contradiction:
Improvesensor mounting flexibilityVSAvoidambient light measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The display assembly is segmented into different functional layers: the display panel that emits light for image display, and the illuminance sensor mounted on the rear surface that detects ambient light. This segmentation allows both functions to coexist in the screen area without interference, as the sensor measures light from the opposite direction (ambient light from outside) rather than receiving display emission.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The display panel itself acts as an intermediary structure that separates the light emission function (front surface) from the light detection function (rear surface). By mounting the sensor on the rear surface of the display assembly, the display panel mediates between the sensor and the external environment, allowing the sensor to detect ambient light through the display structure without being affected by display light emission.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If the illuminance sensor is placed in the vicinity of the front camera or speaker and display, then the sensor can be positioned, but interference with other parts must be considered in design

Engineering Contradiction:
Improvesensor assembly easeVSAvoidinterference with other parts
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The illuminance sensor is merged into the display assembly structure, mounted on the rear surface of the display. This integration eliminates the need to position the sensor in the non-display area near other components, thereby avoiding interference with the front camera, speaker, and other parts while simplifying the overall assembly process.

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 configuration enables accurate ambient light measurement and adjusts the display's brightness effectively, improving user visibility and power efficiency while extending the display's lifespan.

Implementation Method 1

an illuminance sensor may be mounted in a screen area of the display

Methodology Applied
Scientific EffectLight transmission: Light

Data Source

PatentEP3291516B1Electronic device having display and sensor and method for operating the same
Publication Date: 2021.07.21 SAMSUNG ELECTRONICS CO LTD
  • EP3291516B1 patent drawingFigure 1
  • EP3291516B1 patent drawingFigure 2
  • EP3291516B1 patent drawingFigure 3

AI summary

An electronic device having a display and a sensor and methods for operating the same are provided. The electronic device includes a housing, a display disposed on a surface of the housing, a sensor mounted under the display inside the housing to detect light received through the display, and a processor electrically connected with the display and the sensor, wherein the processor is configured to determine an illuminance of an outside of the housing using detection data obtained by the sensor while the display displays an image and relevant information between the display and the sensor.