LED Light Leakage Control via Segmented Phosphor Covers

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Solution Overview

Problem

In light-emitting diodes and lighting devices, varying light emission from the light-emitting element and phosphor occurs depending on the direction of emitted light, and there is a need to prevent unnecessary light leakage in other directions, especially in configurations designed for wide-angle light emission.

Innovation Solution

A light-emitting diode design featuring a light-emitting element with a p-n junction, a light-transmitting member including a phosphor, and covers on opposite surfaces, where the covers extend over the edges of the light-transmitting member to control light direction, with optional use of a second light-transmitting member with a higher diffusion coefficient to manage light emission and reduce leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a light-transmitting member with phosphor is used to emit wide-angle light, then light emission coverage is improved, but light leakage in unnecessary directions occurs

Engineering Contradiction:
Improvelight emission coverageVSAvoidlight leakage
Core Design Contradiction:
Area of stationary objectVSObject-generated harmful factors

Solution Approach 1:

The light-transmitting member is divided into multiple sections with different light transmission properties. The first light-transmitting member has a first light-transmitting region and a second light-transmitting region with different diffusion coefficients, allowing different parts to control light in different directions, thus achieving wide-angle emission while preventing leakage in specific directions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the light-transmitting member are assigned different optical properties. The first light-transmitting region has a first diffusion coefficient while the second light-transmitting region has a second diffusion coefficient that is different from the first, creating localized light control characteristics to manage emission patterns and prevent directional leakage.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If the light-transmitting member is designed for wide-angle emission, then light distribution uniformity is improved, but light leakage control becomes difficult

Engineering Contradiction:
Improvelight distribution uniformityVSAvoidlight leakage control
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The light-transmitting member is segmented into multiple functional regions with different diffusion coefficients. This segmentation allows independent optimization of each region's light distribution characteristics, achieving overall uniformity while maintaining control over directional emission patterns without requiring complex additional components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The diffusion coefficient parameter is varied across different regions of the light-transmitting member. By changing this optical parameter spatially, the patent achieves both wide-angle uniform emission and directional leakage control through material property variation rather than structural complexity.

Inventive Principle:
Principle #35Parameter changes

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 design suppresses directional variation in light emission from the light-emitting element and phosphor, enabling efficient wide-angle light emission while minimizing unnecessary light leakage, thus optimizing light output and reducing loss.

Implementation Method 1

a first light-transmitting member (24) including a phosphor (1)

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 2

a second light-transmitting member (29) with higher diffusion coefficient than the first light-transmitting member (24)

Methodology Applied
Scientific EffectLight diffusion: Scattering

Data Source

PatentEP2815437B1Light-emitting diode and method of manufacturing a light-emitting diode
Publication Date: 2019.08.14 CITIZEN ELECTRONICS CO LTD
  • EP2815437B1 patent drawingFigure 1
  • EP2815437B1 patent drawingFigure 2~3
  • EP2815437B1 patent drawingFigure 4~5

AI summary

In a first aspect of the present invention, a light-emitting diode includes a light-emitting element with a p-n junction, a first light-transmitting member including a phosphor and sealing the light-emitting element, and first and second covers disposed on opposite surfaces of the first light-transmitting member. It is disclosed that the first and second covers extend over edges of the opposite surfaces of the first light-transmitting member. In a second aspect of the present invention, a first cover disposed on a first parallel surface of a first light-transmitting member can be greater in thickness than a second cover. In some embodiments, it is disclosed that a second light-transmitting member with higher diffusion coefficient than the first light-transmitting member disposed in contact with a first perpendicular surface of the first light-transmitting member.