LED Lighting Device with Segmented Current Regulators for Color Stability

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Solution Overview

Problem

Conventional lighting devices, particularly those using incandescent and fluorescent lights, are inefficient in energy usage and have limitations in color rendering index (CRI) and lifespan, while solid state light emitters like LEDs struggle with maintaining color consistency when intensity is adjusted, leading to undesirable color shifts.

Innovation Solution

The use of multiple groups of solid state light emitters with adjustable current regulators to maintain a consistent perceived color and intensity, allowing for incremental dimming without altering the color temperature, by switching between predefined current settings to control the light output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If solid state light emitters are used to improve energy efficiency and lifespan, then energy consumption decreases and lifespan increases, but color consistency deteriorates when intensity is adjusted

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcolor consistency
Core Design Contradiction:
Use of energy by moving objectVSStability of the object's composition

Solution Approach 1:

The lighting device is divided into multiple groups of solid state light emitters, where each group emits light of a different color or shade. Each group is independently controllable through separate current regulators, allowing the system to maintain color consistency while adjusting overall intensity by switching between predefined current settings rather than continuously varying current.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs adjustable current regulators that can switch between multiple predefined current settings for each group of light emitters. This dynamic control allows the system to adapt current levels to maintain consistent perceived color across different intensity levels, resolving the color shift issue that occurs with simple continuous dimming.

Inventive Principle:
Principle #15Dynamics

2Ease of operation

If continuous dimming is implemented to improve ease of operation, then ease of operation increases, but color temperature stability deteriorates

Engineering Contradiction:
Improvedimming controlVSAvoidcolor temperature stability
Core Design Contradiction:
Ease of operationVSTemperature

Solution Approach 1:

The current regulators are designed with multiple adjustable settings that can be switched dynamically. This allows the system to provide ease of operation through flexible intensity control while maintaining color temperature stability by selecting appropriate current combinations that preserve the desired color balance at each intensity level.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters (current levels) of different light emitter groups in a coordinated manner. By adjusting current parameters across multiple groups simultaneously and switching between predefined settings, the system achieves both ease of operation and color temperature stability.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If multiple groups of solid state light emitters with different colors are used to improve CRI, then CRI increases, but device complexity increases

Engineering Contradiction:
ImproveColor Rendering IndexVSAvoidnumber of current regulators
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The lighting device is segmented into multiple groups of solid state light emitters emitting different colors or shades, with each group having its own current regulator. This segmentation improves CRI by combining multiple color emissions while managing complexity through modular design where each regulator handles a specific color group independently.

Inventive Principle:
Principle #1Segmentation

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

This approach enables energy-efficient lighting with improved CRI and longer lifespan, allowing for consistent white light perception across varying intensities without color temperature shifts, addressing the inefficiencies and limitations of traditional lighting technologies.

Implementation Method 1

Light emitting diodes are semiconductor devices that convert electrical current into light

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2033278B1Lighting device and method of lighting
Publication Date: 2019.04.10 WOLFSPEED INC
  • EP2033278B1 patent drawingFigure 1
  • EP2033278B1 patent drawingFigure 2
  • EP2033278B1 patent drawingFigure 3

AI summary

A lighting device, comprising at least first and second current regulators, each switchable among two settings, and at least first and second groups of solid state light emitters. If the first regulator is in a first setting, a first current is supplied to the first group and a second current is supplied to the second group, and if the first regulator is in a second setting, a third current is supplied to the first group and a fourth current is supplied to the second group. In some embodiments, a ratio of the third current divided by the first current differs from a ratio of the fourth current divided by the second current by at least 5 %. Also, a method comprising substantially simultaneously adjusting current supplied to a first group, and adjusting a current supplied to a second group.