LED Chip Filter Layer for Directional Light Emission

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Solution Overview

Problem

Conventional light-emitting diodes (LEDs) with Lambertian radiation characteristics are inefficient for applications requiring directional light emission, especially in compact designs with contact webs that hinder the application of radiation-modifying elements.

Innovation Solution

A light-emitting semiconductor chip with a semiconductor layer sequence grown using epitaxy, featuring a filter layer integrated on the light-outcoupling surface to alter the radiation characteristics, allowing for directional emission without additional optical elements, even with contact structures present.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a separately manufactured filter element is mounted on or over an LED chip to change radiation characteristics, then directional light emission is improved, but device complexity and installation space requirements increase

Engineering Contradiction:

Improvedirectional light emissionVSAvoiddevice complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The filter element is integrated directly into the semiconductor layer sequence during the epitaxial growth process, merging the filtering function with the light-emitting structure. This eliminates the need for separate mounting of filter elements and reduces device complexity while maintaining directional light emission capability

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The filter element is formed in advance during the epitaxial growth of the semiconductor layers, before the final device assembly. This preliminary integration of the filter function into the layer sequence simplifies subsequent manufacturing steps and reduces overall device complexity

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If contact webs are placed on the chip surface to distribute current, then ease of operation is improved, but light emission efficiency deteriorates due to back reflection

Engineering Contradiction:

Improvecurrent distributionVSAvoidlight emission efficiency

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The filter element is positioned in specific regions of the light-outcoupling surface where it can modify radiation characteristics without interfering with the contact webs. This local application of the filtering function allows current distribution through contact webs while maintaining light emission efficiency in other areas

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The filter element is designed to work with the contact webs present, converting the potential harmful effect of back reflection into a beneficial directional emission pattern. The filter modifies the radiation characteristics of light interacting with the contact structure, turning the inefficiency into a controlled directional output

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Illumination intensity

If additional optical elements are added to achieve directional emission, then illumination intensity is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveforward-directed light emissionVSAvoidmanufacturing process

Core Design Contradiction:

Illumination intensityVSEase of manufacture

Solution Approach 1:

The filter element is combined with the semiconductor layer sequence into a single integrated structure grown through epitaxial processes. This merging of the optical filtering function with the semiconductor fabrication process eliminates the need for separate optical element assembly and simplifies manufacturing

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The epitaxial growth process is used to create multiple functional layers simultaneously, including the filter element, semiconductor layers, and contact structures. This multi-functional approach allows a single manufacturing process to achieve what would otherwise require multiple separate steps and components

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 integrated filter layer enhances forward-directed light emission, reducing losses and enabling directional emission without additional optical elements, improving efficiency and compactness.

Implementation Method 1

A light-emitting semiconductor chip has a filter layer on a light-outcoupling surface... the filter layer... alter the radiation characteristics, allowing for directional emission

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

a semiconductor layer sequence with an active layer which is intended and configured to generate light during operation

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS20240387778A1Light-emitting semiconductor chip and method for producing a light-emitting semiconductor chip

Publication Date: 2024.11.21 AMS OSRAM INT GMBH

AI summary

The invention relates to a semiconductor light emitting chip including a semiconductor layer sequence having an active layer which is provided and arranged to generate light when in operation and to couple out via a light outcoupling surface, a filter layer deposited on the light outcoupling surface, and a contact structure deposited on the light outcoupling surface in a region free of the filter layer. The invention also relates to a method for producing said light-emitting semiconductor chip.