LED Emitter with Diffuser Cap for Color Homogeneity

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Solution Overview

Problem

LED emitters with different emission spectra face challenges in achieving color homogeneity across the entire angular range of emitted light, especially when a color conversion layer is used, which can exacerbate the issue of mixed light homogeneity.

Innovation Solution

An LED spotlight design featuring a diffuser cap and reflector configuration, where the diffuser cap is positioned inside the reflector and can be designed as a hollow cylinder with phosphor and scattering particles, ensuring optimal mixing of light from LEDs, including a heat sink in thermal contact with the LED module, and a reflector base with a central opening for LED protrusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple LEDs with different emission spectra are used to achieve white light illumination, then the spectral range is improved, but color homogeneity deteriorates

Engineering Contradiction:

Improvespectral rangeVSAvoidcolor homogeneity

Core Design Contradiction:

Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The emitter is divided into multiple LED chips with different emission spectra (first, second, and third LEDs emitting at different wavelengths) that are spatially separated on the circuit board but optically integrated through the reflector geometry, allowing each chip to contribute its spectral characteristics while maintaining overall color homogeneity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A reflector with a specific geometric shape (parabolic, elliptical, or spherical) is used to redirect light from multiple LED chips positioned at focal points or strategic locations, ensuring that light from different spectral sources is mixed and distributed uniformly across the emission angle

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Use of energy by moving object

If a color conversion layer is applied to convert LED spectrum, then wavelength conversion is improved, but light mixing homogeneity deteriorates

Engineering Contradiction:

Improvewavelength conversionVSAvoidmixed light homogeneity

Core Design Contradiction:

Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

Different portions of the reflector surface are assigned different functions: some areas contain color conversion layers (phosphor materials) while other areas remain reflective, allowing localized wavelength conversion without compromising overall light mixing homogeneity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The reflector acts as an intermediary element that receives light from LEDs, redirects it through color conversion layers, and redistributes the converted light back to the emission direction, ensuring homogeneous mixing of converted and direct light

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If LEDs are arranged on a reflector floor, then device complexity is reduced, but light mixing capability deteriorates

Engineering Contradiction:

Improvestructural simplicityVSAvoidlight mixing capability

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The circuit board carrying multiple LED chips is positioned within the reflector structure, with LEDs arranged on the reflector floor or in close proximity, nesting the LED array within the optical cavity to achieve effective light mixing while maintaining structural simplicity

Inventive Principle:

Principle #7Nested doll (Nesting)

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 configuration enhances light mixing and color homogeneity by premixing light from LEDs and any color conversion material within the diffuser cap before it reaches the reflector, resulting in improved color consistency and efficiency compared to existing technologies.

Implementation Method 1

The light-transmitting medium can have phosphor and/or scattering particles

Methodology Applied

Scientific EffectPhosphor conversion: Photoluminescence

Implementation Method 2

The light-transmitting medium can have phosphor and/or scattering particles

Methodology Applied

Scientific EffectLight scattering: Scattering

Implementation Method 3

a diffuser cap arranged inside the reflector, the diffuser cap enclosing the LED chips wrapped

Methodology Applied

Scientific EffectLight diffusion: Scattering

Implementation Method 4

a reflector surrounding the LED chips at the side

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 5

The LED emitter can have a heat sink that is in thermal contact with the LED module

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2646740B1LED emitter with reflector

Publication Date: 2015.08.26 LUMITECH PRODN & ENTWICKLUNG

Figure 1a~1d
Figure 2
Figure 3

AI summary

The invention relates to an LED emitter, preferably for white light, comprising: - an LED module (5) having a plurality of LED Chips (7, 7') on a carrier (6), - a light-transmissive medium (8), below which the LED chips are accommodated, - a reflector (2) laterally surrounding the LED chips (7, 7'), characterized in that a diffusing cap (900) is arranged within the reflector (2), wherein the diffusing cap (900) encloses the LED chips (7, 7').