Curved Reflector and Light Extractor for Low-Loss LED Emission

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Solution Overview

Problem

Light emitting devices face issues with light loss, moisture penetration, structural stability, and color purity due to inefficiencies in light extraction and external pressure resistance.

Innovation Solution

A light emitting device design incorporating a light emitting semiconductor source, a reflector with a curved reflective surface, and a front-light extractor with a curved body, spacer, and neck structure, optimized to minimize light loss, delay moisture penetration, and enhance structural stability and color purity by adjusting beam angles and curvature ratios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a conventional light emitting diode package is used, then light can be emitted, but light extraction efficiency is insufficient causing light loss

Engineering Contradiction:
Improvelight lossVSAvoidlight extraction efficiency
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The front-light extractor employs a curved outer surface (convex or concave) to optimize light extraction efficiency. The curvature design enables better light emission by controlling refraction and reflection patterns, thereby reducing light loss while maintaining structural integrity and directing light effectively.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent optimizes specific parameters including the radius of curvature of the front-light extractor (R1) relative to the light emitting source length (d1), where R1/d1 ≥ 0.5. Additionally, the reflector's curvature radius (R2) is designed to be greater than or equal to R1. These parameter adjustments maximize light extraction efficiency and minimize light loss.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the light emitting device structure is simplified, then manufacturing is easier, but moisture penetration resistance is reduced

Engineering Contradiction:
Improvestructural simplicityVSAvoidmoisture penetration
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The reflector is designed as a curved shell structure that extends over the light emitting source. This shell provides a protective barrier against moisture penetration while maintaining a relatively simple manufacturing process. The curved geometry naturally directs moisture away from critical components.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The curved geometry of the reflector and front-light extractor creates a streamlined structure that resists moisture penetration. The curvature design allows the device to maintain structural simplicity while effectively preventing moisture ingress through optimized light reflection and moisture diversion pathways.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Strength

If external pressure resistance is increased, then structural stability is improved, but device complexity increases

Engineering Contradiction:
Improveexternal pressure resistanceVSAvoidstructural complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The curved outer surfaces of the front-light extractor and reflector create a dome-like structure that naturally resists external pressure. This geometric design distributes applied forces evenly across the surface, enhancing structural stability without requiring additional support elements or complex internal structures.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent specifies that the radius of curvature R1 should satisfy R1/d1 ≥ 0.5, where d1 is the light emitting source length. This parameter optimization ensures adequate structural strength to resist external pressure while maintaining a simple overall device design without excessive complexity.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If light extraction efficiency is improved through curved surfaces, then light output increases, but chromatic aberration increases

Engineering Contradiction:
Improvelight outputVSAvoidcolor purity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The front-light extractor uses a carefully designed curved surface with radius R1, and the reflector uses curvature R2 ≥ R1. These curved geometries optimize light extraction and direction while the specific radius ratios are chosen to minimize chromatic aberration. The curvature design enables high light output while maintaining acceptable color purity through controlled refraction and reflection.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 design minimizes light loss, delays moisture penetration, improves structural stability, and enhances color purity by optimizing light extraction efficiency and beam angles, while maintaining reliability and reducing chromatic aberration.

Implementation Method 1

a reflector disposed on a side region of the light emitting source while at least partially adjoining the side region of the light emitting source; The reflector may include a first reflective surface formed in at least a region thereof

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a front-light extractor disposed on the light emitting source and the reflector, and including a body comprising a first curved shape

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP4456159A1Light emitting device
Publication Date: 2024.10.30 SEOUL SEMICONDUCTOR
  • EP4456159A1 patent drawingFigure 1
  • EP4456159A1 patent drawingFigure 2
  • EP4456159A1 patent drawingFigure 3

AI summary

Provided is a light emitting device. The light emitting device comprises a light emitting source (120) comprising a light emitting semiconductor device; a reflector (130) disposed on a side region of the light emitting source (120) while at least partially adjoining the side region of the light emitting source (120); a front-light extractor (140) disposed on the light emitting source (120) and the reflector (130) and comprising a body (140a) including a first curved shape; and a substrate (110) including an upper surface on which the light emitting source (120), the reflector (130), and the front-light extractor (140) are mounted. The reflector (130) comprises a first reflective surface (130a) in at least a region thereof and including a second curved shape, and the second curved shape of the first reflective surface (130a) includes a radius of curvature (R2) greater than or equal to a radius of curvature (R1) of the first curved shape of the front-light extractor (140).