Multi-Chip LED Package Layout for Uniform Far-Field Color Mixing

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Solution Overview

Problem

Conventional LED packages with multiple LED chips of different colors exhibit varying color intensities with viewing angle, leading to non-uniform color displays due to differing far field patterns.

Innovation Solution

The LED packages incorporate multiple LED chips within a single recess and a corresponding lens, with optimized chip arrangements and cladding layers to reduce lensing effects, achieving a full width half maximum of less than 50 degrees and a color quality index metric of 0.7 to 0.96, enhancing color uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple LED chips of different colors are arranged in separate cavities with individual lenses, then each chip can be independently optimized, but the far field patterns exhibit varying color intensities with viewing angle leading to non-uniform color displays

Engineering Contradiction:

Improvecolor uniformityVSAvoidviewing angle consistency

Core Design Contradiction:

Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent merges multiple LED chips of different colors into a single shared cavity with a common lens structure. This integration allows the light from multiple chips to mix and propagate together, eliminating the separate cavity isolation that caused viewing angle-dependent color variations. The shared optical path ensures uniform color output across different viewing angles.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent applies local quality by positioning specific LED chips at optimized locations within the shared cavity and applying selective cladding layers to specific lens regions. This localized optimization controls the far field pattern contributions from each chip, ensuring that color intensities remain uniform across viewing angles while maintaining manufacturing precision.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If a single lens is used over multiple LED chips in a shared cavity, then color mixing is improved, but lensing effects cause far field pattern variations

Engineering Contradiction:

Improvecolor mixing uniformityVSAvoidfar field pattern uniformity

Core Design Contradiction:

Manufacturing precisionVSIllumination intensity

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent modifies lens parameters by introducing cladding layers with specific refractive indices on portions of the lens surface. This changes the optical parameters of the lens system, reducing unwanted lensing effects and improving far field pattern uniformity while maintaining effective color mixing.

Inventive Principle:

Principle #35Parameter changes

3Illumination intensity

If cladding layers are added to the lens, then far field pattern uniformity is improved, but device complexity increases

Engineering Contradiction:

Improvefar field pattern uniformityVSAvoidlens structure complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The cladding layers are applied selectively to specific portions of the lens surface rather than uniformly across the entire lens. This localized application reduces far field pattern variations while minimizing the increase in device complexity by only modifying the regions that require optical correction.

Inventive Principle:

Principle #3Local quality

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 solution provides improved color uniformity and reduced far field pattern variations, ensuring consistent color output across different viewing angles.

Implementation Method 1

a lens over the recess

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

the cladding layer comprises a light-reflective material

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 3

the cladding layer comprises a light-absorbing material

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS20250293215A1Light mixing arrangements in multiple-chip light-emitting diode packages

Publication Date: 2025.09.18 CREELED INC

AI summary

Light-emitting diode (LED) packages and more particularly light mixing arrangements in LED packages are disclosed. LED packages include multiple LED chips arranged within a single recess or cavity and a single corresponding lens. Light mixing arrangements include LED chip layouts, lens structures, and/or cladding layers for lens structures. LED packages are disclosed with reduced full width half maximum values and improved uniformity in far field pattern emissions by reducing lensing effects of multiple LED chips in a single cavity. A figure of merit is described that defines a color quality index metric that characterizes color quality and uniformity of far field emissions in multiple-color and multiple-chip LED packages.