Multi-Channel Rhythm Spectrum Modulation for High-CRI Day-Night Lighting

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Solution Overview

Problem

Existing methods struggle to simultaneously achieve high Color Rendering Index (CRI) and appropriate rhythmic stimulation levels in indoor lighting, affecting visual and physiological effects, and fail to meet standards like the Shanghai Group Standard T/SIEATA Ranking Evaluation for Classroom Lighting Quality.

Innovation Solution

A method involving a combination of white, blue, green, and blue-green LEDs on a substrate, with specific luminous flux adjustments to create daytime and nighttime rhythmic spectra, ensuring high CRI and desired rhythmic stimulation levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the rhythmic stimulation effect is adjusted by controlling light intensity and color temperature, then the rhythmic stimulation level is improved, but the visual effect deteriorates due to inevitable changes in color temperature and color rendering index

Engineering Contradiction:
Improverhythmic stimulation effectVSAvoidvisual effect
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent segments the light source into multiple independent LED channels (warm white LED, blue LED, green LED, blue-green LED) that can be individually controlled. This allows separate adjustment of rhythmic stimulation (through blue LED at 450-465nm) and visual quality (through warm white LED with CRI>80), resolving the contradiction between rhythmic effect and visual effect

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the spectral composition parameters by introducing specific wavelength LEDs (blue 450-465nm, green 540-560nm, blue-green 490-500nm) alongside warm white LED (2600-3300K). This parameter change enables independent control of melanopic luminous flux for rhythmic stimulation while maintaining high CRI for visual quality

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the EML value is increased to meet daytime standards (EML≥200), then the rhythmic stimulation effect is improved, but the visual effect deteriorates due to required high illuminance (≥500 Ix)

Engineering Contradiction:
Improverhythmic stimulation effectVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the spectral power distribution parameters by adding blue LED (450-465nm) and blue-green LED (490-500nm) channels to enhance melanopic luminous flux efficiency. This allows achieving EML≥200 with more efficient spectral composition, reducing the energy required to reach the same rhythmic stimulation level

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the EML value is decreased to meet nighttime standards (EML≤130), then the rhythmic stimulation effect is improved for nighttime, but the visual effect deteriorates due to required illuminance (≥300 Ix)

Engineering Contradiction:
Improverhythmic stimulation effectVSAvoidvisual effect
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent segments the lighting system into independent controllable channels, allowing the blue LED (rhythmic stimulation) to be reduced for nighttime (0.72-0.88% luminous flux) while maintaining warm white LED (61.8-69.3% luminous flux) for adequate visual illumination, thus achieving EML≤130 with sufficient visual quality

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic adjustment of luminous flux ratios between different LED channels based on time of day. During nighttime, the system dynamically reduces blue LED contribution while maintaining warm white LED dominance, enabling transition from daytime rhythmic profile to nighttime rhythmic profile with appropriate visual quality

Inventive Principle:
Principle #15Dynamics

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 method achieves strong rhythmic stimulation with high CRI during the day and weak stimulation at night, enhancing learning and working efficiency while reducing melatonin secretion, meeting lighting standards for classrooms and night environments.

Implementation Method 1

providing a white light-emitting diode (LED), a blue LED, a green LED and a blue-green LED on a substrate

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Implementation Method 2

The ipRGCs are activated by internal photosensitive proteins called melanopsin

Methodology Applied
Scientific EffectMelanopsin activation:

Data Source

PatentEP4395464B1Rhythm spectrum modulation method
Publication Date: 2025.08.06 FOSHAN ELECTRICAL & LIGHTING
  • EP4395464B1 patent drawingFigure 1
  • EP4395464B1 patent drawingFigure 2
  • EP4395464B1 patent drawingFigure 3

AI summary

The present disclosure provides a method for modulating a rhythmic spectrum, including: providing a white light-emitting diode (LED), a blue LED, a green LED and a blue-green LED; and adjusting a luminous flux of each LED, thereby obtaining a rhythmic spectrum with a preset luminous flux, where the luminous flux of the white LED, the luminous flux of the blue LED, the luminous flux of the green LED, and the luminous flux of the blue-green LED respectively account for 62.32-75.9%, 1.74-1.91%, 1.5-20.27% and 15.5-22.8% in the preset luminous flux; or the luminous flux of the white LED, the luminous flux of the blue LED, the luminous flux of the green LED, and the luminous flux of the blue-green LED respectively account for 61.8-69.3%, 0.72-0.88%, 28.6-37.31% and 0-1.8% in the preset luminous flux. The present disclosure can obtain the rhythmic spectrum with an appropriate rhythmic stimulation effect, and is suitable for daily use.