LED Light Bulb With Parallel White Light Sources For Color Temperature Control

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Solution Overview

Problem

Conventional LED light sources struggle to adjust brightness while maintaining color temperature variability, requiring changes in phosphor or LED types to alter emission color, which is not intuitive like incandescent bulbs.

Innovation Solution

A light emitting device with multiple white light sources of different color temperatures, connected in parallel and series, using phosphors of specific compositions to produce mixed white light, allowing for adjustable color temperature and brightness through current control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional white light source uses a single phosphor type with LED, then the structure is simple, but the color temperature cannot be varied with brightness adjustment

Engineering Contradiction:
Improvecolor temperature variabilityVSAvoidlight source structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides the white light source into multiple segments, each emitting light at different color temperatures (e.g., first white light source at higher color temperature, second white light source at lower color temperature). This segmentation allows independent control of each segment's brightness to achieve variable color temperature mixing, resolving the contradiction between adaptability and structural simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges multiple white light sources with different color temperatures into a single integrated light emitting device. By combining these diverse light sources and controlling their relative intensities, the system achieves variable color temperature output while maintaining a unified structure, thus balancing adaptability and device complexity.

Inventive Principle:
Principle #5Merging (Combining)

2Illumination intensity

If brightness of LED is adjusted in conventional white light source, then brightness control is achieved, but color temperature remains constant

Engineering Contradiction:
Improvebrightness controlVSAvoidcolor temperature adjustment
Core Design Contradiction:
Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic control where the brightness of each white light source is independently adjustable. By dynamically varying the intensity ratio between high color temperature and low color temperature light sources, the system achieves both brightness control and color temperature adjustment simultaneously, resolving the contradiction between illumination intensity control and color temperature adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operating parameters of multiple light sources to achieve dual control. By independently adjusting the current or voltage supplied to each white light source, the system can vary both the total brightness and the color temperature of the combined light output, thus resolving the contradiction between fixed color temperature and adjustable brightness.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If multiple white light sources are used to achieve color temperature variation, then color temperature adjustability is improved, but device complexity increases

Engineering Contradiction:
Improvecolor temperature rangeVSAvoidnumber of light sources
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent designs each white light source to serve multiple functions: they collectively provide both brightness control and color temperature adjustment. By making the system multi-functional through the coordinated operation of multiple light sources, the patent achieves wide color temperature range without proportionally increasing overall device complexity, as the control system manages multiple functions through integrated control.

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

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

Enables adjustable color temperature and brightness control, mimicking incandescent bulb behavior by varying the current to white light sources, achieving a wide range of color temperatures and luminous flux while maintaining high color rendering index.

Implementation Method 1

a first white light source 71 and a second white light source 72 which emit first and second white lights with different color temperatures, respectively

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP3122160B1Light-emitting device and LED light bulb
Publication Date: 2021.05.05 TOSHIBA MATERIALS CO LTD
  • EP3122160B1 patent drawingFigure 1
  • EP3122160B1 patent drawingFigure 2
  • EP3122160B1 patent drawingFigure 3

AI summary

A light emitting device includes: a first white light source which includes N pieces of first white light emitting diodes and emits a first white light; and a second white light source which includes M pieces of second white light emitting diodes and a first resistance element electrically connected in series to the second white light emitting diodes and having a first resistance value, is electrically connected in parallel to the first white light source, and emits a second white light, the light emitting device emitting a mixed white light of the first white light and the second white light. The drive voltage of the first white light source is higher than a drive voltage of the second white light source, and a color temperature of the mixed white light is higher as a total luminous flux of the mixed white light is higher.