Direct Red LED White Light Tuning for TM-30 Color Quality

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Solution Overview

Problem

Existing lighting devices and systems struggle to meet desirable lighting quality standards, such as TM-30(2020) requirements, with inefficient solutions and limited control over spectral power distribution and melanopic efficacy.

Innovation Solution

A light generating system comprising primary and secondary solid state light sources, along with first and second luminescent material arrangements, configured to generate light with adjustable correlated color temperatures and enhanced melanopic efficacy, using a control system to manage spectral power distributions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional lighting devices use single or simple multi-LED configurations, then device complexity is reduced, but they cannot meet TM-30(2020) priority level 1 and fidelity level 3 requirements across wide color temperature ranges

Engineering Contradiction:
Improvecompliance with lighting quality standardsVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The lighting system is divided into multiple independent light generating channels (first channel with blue LED + first phosphor, second channel with blue LED + second phosphor, third channel with red LED). Each channel can be independently controlled to achieve precise spectral power distribution management, enabling compliance with TM-30(2020) P1F3 requirements across wide color temperature ranges while maintaining modular simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements dynamic control of multiple light generating channels with independent dimming capabilities. The control system adjusts the intensity of each channel to dynamically tune correlated color temperature and spectral power distribution, enabling adaptive compliance with lighting quality standards across different operating conditions

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If lighting systems use multiple LED channels with independent control, then spectral power distribution control is improved, but device complexity increases

Engineering Contradiction:
Improvespectral power distribution controlVSAvoidcontrol system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The control system serves multiple functions simultaneously: it controls dimming of individual LED channels, manages phosphor excitation, tunes correlated color temperature, and ensures compliance with TM-30(2020) spectral power distribution requirements. This multi-functionality reduces the need for separate control circuits for each parameter, managing complexity while enhancing adaptability

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Use of energy by moving object

If conventional systems use blue pump LEDs with phosphor conversion, then energy efficiency is improved, but melanopic efficacy and color quality at low correlated color temperatures remain insufficient

Engineering Contradiction:
Improveenergy efficiencyVSAvoidmelanopic efficacy
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system adds a dedicated red LED channel (610-630 nm) that specifically targets the spectral region critical for melanopic stimulation and color rendering at low correlated color temperatures. This localized spectral enhancement complements the blue-phosphor conversion channels, improving melanopic efficacy without compromising overall energy efficiency, as the red channel only activates when needed for specific color temperature ranges

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 system efficiently meets TM-30(2020) requirements across a wide range of correlated color temperatures, including low values, while allowing control over melanopic daylight illuminance and efficacy, providing high color quality and efficiency.

Implementation Method 1

the first luminescent material arrangement is configured to convert at least part of the primary light of the at least one primary solid state light source into first luminescent material arrangement light

Methodology Applied
Scientific EffectLuminescence: Luminescence

Implementation Method 2

an optical component that is positioned to receive at least a portion of the off-white light generated by the one or more light sources, the optical component comprising an optical material for converting at least a portion of the off-white light to one or more predetermined wavelengths

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP4578249B1Direct red LED for white light with high user preference
Publication Date: 2026.02.18 SIGNIFY HOLDING BV
  • EP4578249B1 patent drawingFigure 1A~1B
  • EP4578249B1 patent drawingFigure 2A
  • EP4578249B1 patent drawingFigure 2B~2C

AI summary

The invention provides a light generating system (1000) comprising one or more primary solid state light sources (50), one or more secondary solid state light sources (60), a first luminescent material arrangement (1210), a second luminescent material arrangement (1220), and a control system (300), wherein: (A) the one or more primary solid state light sources (50) are configured to generate primary light (51); (B) the one or more secondary solid state light sources (60) are configured to generate secondary light (61); (C) the first luminescent material arrangement (1210) is configured in a light receiving relationship with at least one primary solid state light source (50) and is configured to convert at least part of the primary light (51) of the at least one primary solid state light source (50) into first luminescent material arrangement light (1211); wherein when the at least one primary solid state light source (50) alone irradiates the first luminescent material arrangement (1210) a first spectral power distribution, comprising the primary light (51) (of the at least one primary solid state light source (50)) and the first luminescent material arrangement light (1211), is obtained; (D) the second luminescent material arrangement (1220) is configured in a light receiving relationship with at least one (other) primary solid state light source (50) and is configured to convert at least part of the primary light (51) into second luminescent material arrangement light (1221); wherein when the at least one (other) primary solid state light source (50) alone irradiates the second luminescent material arrangement (1220) a second spectral power distribution, comprising the primary light (51) and the second luminescent material arrangement light (1221), is obtained; (E) the first spectral power distribution and the second spectral power distribution have v' values differing at least 0.02; wherein the first spectral power distribution has a first color point outside 10 standard deviation of color matching (SDCM) from the black body locus, and wherein the second spectral power distribution has a second color point outside 10 standard deviation of color matching (SDCM) from the black body locus.