Solid State Lighting Module Lumen Output and Color Point Control

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Solution Overview

Problem

Existing semiconductor light emitting devices, particularly those using phosphor-based solid state lighting components, often have a low color rendering index (CRI), leading to unnatural object coloring due to limited light spectrum, and struggle to balance color point, CRI, and lumen output in lighting modules.

Innovation Solution

A lighting module comprising a plurality of solid state light emitting components configured to provide collective light emission with a desired color point and CRI, supplemented by an additional light emitting component that emits light over a different wavelength range to increase lumen output without altering the desired white point, using a combination of blue shifted yellow, red, warm-white, or neutral-white LEDs and wavelength conversion materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If phosphor-based solid state lighting components are used to generate white light, then energy efficiency is improved, but color rendering index deteriorates

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcolor rendering index
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent combines multiple solid state light emitting components with different emission characteristics (blue LED with yellow phosphor, red LED, green LED) to create a composite light source that achieves both high energy efficiency and high CRI (>90) by merging their spectral outputs

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple wavelength conversion materials are used to improve CRI, then color rendering index is improved, but device complexity increases

Engineering Contradiction:
Improvecolor rendering indexVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the lighting system into multiple independent solid state light emitting components, each responsible for specific wavelength ranges, allowing simplified individual component design while achieving complex spectral output collectively

Inventive Principle:
Principle #1Segmentation

3Reliability

If red-emitting elements are added to improve CRI, then color rendering index is improved, but maintaining color point becomes difficult

Engineering Contradiction:
Improvecolor rendering indexVSAvoidcolor point
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by assigning specific functional roles to different components: blue LED with yellow phosphor provides base white light, red LED specifically enhances CRI in the red spectrum, and green LED fills the green spectrum gap, with each component optimized for its local spectral region while contributing to overall color point stability

Inventive Principle:
Principle #3Local quality

4Productivity

If lumen output is increased by adding more light emitting components, then luminous flux is improved, but color point stability deteriorates

Engineering Contradiction:
Improveluminous fluxVSAvoidcolor point
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The patent uses parameter changes by adjusting the relative intensities and spectral characteristics of each light emitting component to achieve desired color points while maximizing total luminous flux output

Inventive Principle:
Principle #35Parameter changes

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 achieves a CRI greater than 90 and increased luminous flux while maintaining the desired color point, approximating the performance of incandescent lamps in object illumination.

Implementation Method 1

Light emitting diodes and laser diodes are well known solid state lighting elements capable of generating light upon application of a sufficient current

Methodology Applied
Scientific EffectLight emitting diode effect: Light Emitting Diode

Implementation Method 2

The radiative recombination of electrons and holes within the active region generates light

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 3

The light from a single-color LED may be converted to white light by surrounding the LED with a wavelength conversion material, such as a phosphor

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Implementation Method 4

A fraction of the light may also pass through the phosphor and/or be reemitted from the phosphor at essentially the same wavelength as the incident light

Methodology Applied
Scientific EffectWavelength conversion: Photoluminescence

Data Source

PatentEP2671019B1Lighting apparatus providing increased luminous flux while maintaining color point and cri
Publication Date: 2016.11.23 WOLFSPEED INC
  • EP2671019B1 patent drawingFigure 1~2
  • EP2671019B1 patent drawingFigure 3A~3C
  • EP2671019B1 patent drawingFigure 4A~5A

AI summary

A lighting module includes a plurality of solid state light emitting components configured to collectively emit light having a desired white point and a color rendering index (CRI) of greater than about 90. The module further includes at least one additional solid state light emitting component configured to individually emit light having a white point substantially similar to the desired white point. The at least one additional light emitting component may increase a lumen output of the lighting module without substantially altering the desired white point of the light collectively emitted by the plurality of light emitting components.