Retroreflector Ambient Light Visibility for Organic LED Lighting

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Solution Overview

Problem

Conventional lighting devices lack visibility when not in operation or if the organic light-emitting component is defective, as they do not effectively utilize ambient light for visibility purposes.

Innovation Solution

A lighting device incorporating an organic light-emitting component with a retroreflector that couples and reflects ambient light, maintaining visibility by reflecting ambient light back through the light passage surface, even when the organic light-emitting component is switched off or defective, using a wavelength-selective retroreflector to match the color impression of the organic light-emitting component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional lighting devices are used without retroreflector, then the structure is simple, but visibility when not in operation is poor

Engineering Contradiction:
ImprovevisibilityVSAvoidstructure
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent combines the retroreflector with the light passage surface into an integrated component. The retroreflector is positioned behind the light passage surface and works together with it to reflect ambient light back through the same surface, achieving improved visibility without adding separate complex components. This merging approach resolves the contradiction by integrating the reflective function into the existing light passage structure.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If ambient light is not reflected back through light passage surface, then device complexity is low, but visibility when organic light-emitting component is defective is poor

Engineering Contradiction:
Improvevisibility when defectiveVSAvoidstructure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The retroreflector is pre-positioned behind the light passage surface to automatically reflect ambient light back through the surface when the organic light-emitting component is not functioning. This preliminary arrangement ensures that visibility is maintained in failure conditions without requiring active control or additional components, resolving the contradiction between reliability and device complexity.

Inventive Principle:
Principle #10Preliminary action

3Illumination intensity

If retroreflector reflects ambient light in wide angles, then visibility from multiple directions is improved, but light is reflected back into external light source instead of toward observer

Engineering Contradiction:
Improvevisibility for observerVSAvoidlight reflection into source
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The retroreflector is positioned specifically behind the light passage surface at a defined distance, creating a localized reflective zone. This positioning ensures that ambient light reflected by the retroreflector passes through the light passage surface and reaches observers in front of the device, rather than reflecting back into the external light source. The local positioning resolves the contradiction by controlling the reflection geometry to favor observer visibility while avoiding harmful back-reflection.

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

Ensures good visibility of the lighting device through ambient light reflection, maintaining a consistent color impression regardless of the organic light-emitting component's operational state, enhancing visibility and information display even when the component is not functioning.

Implementation Method 1

a retroreflector (5), which is provided for reflecting at least part of the ambient light coupled in through the light passage surface (7) back to the light passage surface (7)

Methodology Applied
Scientific EffectRetroreflection: Retroreflector

Implementation Method 2

a light passage surface (7) which is provided for coupling light emitted by the organic light-emitting component (2) out of the lighting device (1) and coupling ambient light into the lighting device (1)

Methodology Applied
Scientific EffectLight coupling: Refraction

Data Source

PatentEP2043176B1Lighting device, lights and display device
Publication Date: 2019.01.09 OSRAM OLED
  • EP2043176B1 patent drawingFigure 1A~2
  • EP2043176B1 patent drawingFigure 3~4
  • EP2043176B1 patent drawingFigure 5~6

AI summary

The device (1) has an organic light emitting component (2) e.g. organic LED, with a functional layer sequence (23) for light generation. A light transmission surface (7) decouples light emitted from the organic light emitting components, and couples ambient light in the illumination device. A retro-reflector (5) reflects a part of the coupled ambient light back to the light transmission surface. The light emitting components are designed to be partially transparent, and the functional layer sequence is arranged between the light transmission surface and the reflector.