Non-Rectangular LED Emission Surfaces for Optical Aperture Matching

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Solution Overview

Problem

Conventional light-emitting diodes (LEDs) with rectangular emission surfaces are not optimized for use in optical systems with circular or non-rectangular input apertures, leading to inefficiencies in light transmission and increased etendue, which limits the extent to which narrow beams of light can be projected.

Innovation Solution

The emission surface of the LED is shaped to match the input aperture, either through the use of non-rectangular polygonal emission surfaces or emitter output apertures, such as circular or pentagonal shapes, to enhance optical and thermal efficiencies by ensuring that a larger amount of light is transmitted while preserving the etendue of the source.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a rectangular emission surface is used in conventional LEDs, then the manufacturing process is simple, but the light transmission efficiency is reduced when used with circular or non-rectangular input apertures

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidlight transmission efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent changes the geometric parameter of the emission surface from rectangular to non-rectangular (circular, polygonal, or irregular shapes) to match the input aperture geometry. This parameter change optimizes light transmission efficiency by eliminating wasted light from corners that cannot pass through circular apertures, while the manufacturing process remains compatible with standard LED fabrication techniques.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the emission surface shape is changed to match the input aperture, then the optical efficiency is improved, but the device complexity increases

Engineering Contradiction:
Improveoptical efficiencyVSAvoidemission surface geometry
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent applies local quality by modifying only the emission surface geometry at the light-output interface while keeping the internal LED structure and manufacturing processes standard. This localized change optimizes optical coupling efficiency without requiring complex modifications throughout the entire device, thus improving optical efficiency with minimal increase in overall device complexity.

Inventive Principle:
Principle #3Local quality

3Area of stationary object

If a rectangular emission surface is used, then the etendue is increased, but the beam narrowness is limited

Engineering Contradiction:
Improveemission surface areaVSAvoidbeam convergence
Core Design Contradiction:
Area of stationary objectVSSpeed

Solution Approach 1:

The patent employs curved geometries (circular or polygonal emission surfaces) instead of rectangular shapes to better match the circular input aperture of optical systems. This curved geometry reduces the etendue by eliminating corner regions that contribute to beam divergence, thereby enabling narrower beam projection while maintaining effective light transmission through the aperture.

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

This approach increases the lumens per etendue of the system, reduces light loss, and allows for more efficient heat dissipation, thereby improving the overall performance and efficacy of LED-based optical systems.

Implementation Method 1

A light-emitting diode (LED) often can provide light in a more efficient manner than an incandescent light source and/or a fluorescent light source

Methodology Applied
Scientific EffectLight-emitting diode effect: Light Emitting Diode

Implementation Method 2

During use, electrical energy is usually injected into an LED and then converted into electromagnetic radiation (light)

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2727156B1Light-emitting diode architectures for enhanced performance
Publication Date: 2021.03.24 LUMINUS DEVICES INC
  • EP2727156B1 patent drawingFigure 1A~1B
  • EP2727156B1 patent drawingFigure 1C~1D
  • EP2727156B1 patent drawingFigure 1E~1F

AI summary

The present invention relates to light-emitting diodes (LEDs), and related components, processes, systems, and methods. In certain embodiments, an LED that provides improved optical and thermal efficiency when used in optical systems with a non-rectangular input aperture (e.g., a circular aperture) is described. In some embodiments, the emission surface of the LED and/or an emitter output aperture can be shaped (e.g., in a non-rectangular shape) such that enhanced optical and thermal efficiencies are achieved. In addition, in some embodiments, chip designs and processes that may be employed in order to produce such devices are described.