Light-emitting Device with Inclined Structured Light Exit Layer

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional light-emitting devices, such as OLEDs, exhibit a Lambertian emission profile, which is not suitable for lighting applications that require a directed radiation profile.

Innovation Solution

The design of a light-emitting device with a light-emitting layer and a light exit layer featuring inclined, parallel surfaces, where only the first surfaces are transparent and the second surfaces are reflective, allowing for a non-perpendicular main radiation direction that deviates from the Lambertian emission profile. This can include structured surfaces using prisms, cones, or anisotropic scattering particles to achieve desired radiation patterns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a planar light exit layer is used, then the device structure is simple, but the emission profile is Lambertian with main radiation perpendicular to the light-emitting layer, which is unsuitable for directed lighting applications

Engineering Contradiction:
Improvestructural simplicityVSAvoidemission profile adaptability
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The light exit layer is segmented into multiple inclined surfaces (first surfaces and second surfaces) with different orientations. Each surface segment directs light in a specific direction, enabling the overall structure to produce a non-Lambertian, directed emission profile while maintaining manufacturing feasibility through modular surface design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from a two-dimensional planar light exit surface to a three-dimensional structured surface with inclined first surfaces and second surfaces. This dimensional change allows light to be emitted in directed angles rather than perpendicular to the plane, achieving the desired non-Lambertian emission profile suitable for lighting applications

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If the first surfaces and second surfaces have large extension dimensions, then the directed radiation effect is enhanced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveradiation direction controlVSAvoidsurface geometry precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Different regions of the light exit layer are assigned different functions: first surfaces are optimized for light extraction with specific inclination angles, while second surfaces are designed with reflective properties. This local differentiation allows each surface to be manufactured with precision tailored to its specific function, reducing overall manufacturing complexity while maintaining directed radiation performance

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

The solution enables light-emitting devices to produce directed radiation profiles suitable for various applications, including general lighting and signaling, by optimizing the emission direction and intensity, enhancing their suitability for specific use cases.

Implementation Method 1

The second surfaces are reflective for light emitted from the light-emitting layer. The second surfaces are made reflective by vaporizing metal particles.

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The second surfaces are made reflective by vaporizing metal particles.

Methodology Applied
Scientific EffectVapor deposition: Physical Vapour Deposition

Data Source

PatentEP2220521B1Light-emitting device
Publication Date: 2018.01.10 OSRAM OLED
  • EP2220521B1 patent drawingFigure 1
  • EP2220521B1 patent drawingFigure 2a~2d
  • EP2220521B1 patent drawingFigure 3a~3b

AI summary

An embodiment of the invention relates to a light-emitting device, which comprises a light-emitting layer (1) and a light-exiting layer (4). For this purpose, the light-exiting layer (4) comprises a plurality of mutually parallel first surfaces (5), which are disposed at an incline to the light-emitting layer (1). The light-exiting layer (4) comprises furthermore a plurality of mutually parallel second surfaces (6), which are disposed at an incline to the light-emitting layer (1) and at an incline to the first surfaces (5). The first surfaces (5) are transparent and the second surfaces (6) reflect light emitted by the light-emitting layer (1).