Dual-Wavelength Light-Emitting Device with Selective Reflection Layers

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Solution Overview

Problem

Infrared light from the display unit can enter the infrared ray emitting unit, causing deterioration of display quality by reflected light in existing gaze detection systems.

Innovation Solution

A light emitting device with a first light emitting element for visible light and a second light emitting element for infrared rays, where the second reflection layer has a lower average reflectance for visible light compared to the first, reducing reflected light interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a reflection layer is provided in the infrared ray emitting unit to improve infrared ray emission efficiency, then infrared ray emission efficiency is improved, but reflected light from the display unit deteriorates display quality

Engineering Contradiction:

Improveinfrared ray emission efficiencyVSAvoiddisplay quality deterioration

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent applies different reflection layer configurations to different units: the display unit has a reflection layer for efficient visible light emission, while the infrared ray emitting unit has a reflection layer optimized for infrared ray emission with lower visible light reflectance. This local differentiation resolves the contradiction by tailoring each unit's optical properties to its specific function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the optical parameters of the reflection layer in the infrared ray emitting unit by using materials or structures with lower visible light reflectance while maintaining infrared ray emission efficiency. This parameter optimization allows the unit to fulfill its infrared emission function without causing harmful reflections to the display unit.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If the same reflection layer is used in both display unit and infrared ray emitting unit, then manufacturing is simplified, but infrared ray emission efficiency is reduced

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidinfrared ray emission efficiency

Core Design Contradiction:

Ease of manufactureVSPower

Solution Approach 1:

The patent segments the optical system into two distinct units with different reflection layer requirements. By providing separate reflection layer configurations for the display unit and infrared ray emitting unit, the patent optimizes each unit's performance while maintaining manageable manufacturing complexity through modular design.

Inventive Principle:

Principle #1Segmentation

3Illumination intensity

If the infrared ray emitting unit has high reflectance for visible light, then visible light emission is improved, but reflected light from display unit deteriorates display quality

Engineering Contradiction:

Improvevisible light emissionVSAvoiddisplay quality deterioration

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

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 configuration minimizes display quality deterioration while maintaining efficient infrared ray emission, enhancing visibility and gaze detection accuracy.

Implementation Method 1

a first reflection layer between the substrate and the first light emitting layer

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 2

a second reflection layer between the substrate and the second light emitting layer

Methodology Applied

Scientific EffectInfrared radiation: Infrared Radiation

Data Source

PatentUS20250331394A1Light emitting device, display device, image capturing device, electronic apparatus, and wearable device

Publication Date: 2025.10.23 CANON KK

AI summary

A light emitting device including, on a substrate, a first light emitting element configured to emit visible light and a second light emitting element configured to emit an infrared ray. The first light emitting element includes a first light emitting layer, and a first reflection layer between the substrate and the first light emitting layer, the second light emitting element includes a second light emitting layer, and a second reflection layer between the substrate and the second light emitting layer. An average reflectance of the second reflection layer for visible light is lower than an average reflectance of the first reflection layer for visible light.