LED Light Transmission Part for Thermal Load Reduction

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Solution Overview

Problem

High thermal load on light guides due to large angle light rays being absorbed rather than transmitted, leading to potential damage, especially when high luminous fluxes are required at the output of LED-based lighting devices.

Innovation Solution

A lighting device with a light transmission part having two sections: a first section with a widening cross-section and angle-independent reflective lateral surface to redirect light rays, and a second section with a constant cross-section and angle-dependent reflective lateral surface to filter out non-transmissible rays, minimizing thermal stress on the light guide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If large luminous fluxes are provided by the LED to achieve high light output at the output end, then the light output is improved, but the thermal load on the light guide increases leading to potential damage

Engineering Contradiction:
Improvelight outputVSAvoidthermal load
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The light transmission part is divided into two functional sections: a first section with a widening cross-section for angular transformation, and a second section with constant cross-section for light guide coupling. This segmentation allows each section to perform its specific function optimally, transforming light angles in the first section before coupling into the light guide in the second section, thereby reducing thermal load while maintaining high light output.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different sections of the light transmission part are given different geometric properties: the first section has a widening cross-section with specific lateral surfaces for angular transformation, while the second section has a constant cross-section optimized for light guide coupling. This local differentiation of geometric quality enables the system to simultaneously achieve high luminous flux transmission and reduced thermal load through appropriate angular transformation in each zone.

Inventive Principle:
Principle #3Local quality

2Use of energy by moving object

If light rays at large angles to the optical axis are transmitted, then the luminous flux is improved, but these rays are absorbed by the light guide converting to heat

Engineering Contradiction:
Improveluminous fluxVSAvoidheat conversion
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The first section of the light transmission part performs preliminary angular transformation of light rays before they enter the light guide. By pre-transforming the angles of light rays in the first section through its widening cross-section geometry, the system ensures that only appropriately angled rays are coupled into the light guide, preventing excessive angular rays from being absorbed and converted to heat while maximizing luminous flux transmission.

Inventive Principle:
Principle #10Preliminary action

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

Significantly increases luminous flux output while reducing thermal load on the light guide, preventing damage and enhancing efficiency by optimizing light transmission and reflection within the light guide.

Implementation Method 1

a lateral surface that reflects the radiation entering the first section independently of the angle

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

at least one lateral surface that reflects the radiation entering the second section from the first section in an angle-dependent manner

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

a light guide for forwarding the light emitted by the LED... each consisting of a core made from a core glass and surrounded by a cladding made from a cladding glass

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3407772B1Illuminating device
Publication Date: 2021.06.09 RICHARD WOLF GMBH
  • EP3407772B1 patent drawingFigure 1~3
  • EP3407772B1 patent drawingFigure 4~6
  • EP3407772B1 patent drawingFigure 7~9

AI summary

The invention relates to an illuminating device. Said illuminating device is provided with an LED (2) as a light source and a light guide (6) for conveying the light emitted by the LED (2). A light transmission part (10') is arranged between the LED (2) and the light guide (6). Said light transmission part (10) comprises two sections (14, 16), of which one first section (14) directly facing the LED (2) comprises a cross-section which expands with increasing distance from the LED (2) and a lateral surface (22) reflecting the radiation entering the first section in an angle-independent manner, and a second section directly facing the light guide (6) comprises at least one lateral surface (24) reflecting the radiation entering the second section (16) from the first section (14) in an angle-dependent manner.