Lighting Device With Segmented LED Sources For Mesopic Visibility

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Solution Overview

Problem

Existing lighting devices do not effectively improve visibility under mesopic vision environments while reducing power consumption and component complexity.

Innovation Solution

A lighting device incorporating two LED light sources with different wavelengths, one emitting short wavelength blue light and the other long wavelength light, with a fluorescent body to emit yellow light, and a backup power system to ensure continuous operation during power interruptions, allowing for adaptive spectral control to enhance visibility and reduce power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If three types of LED light sources having different wavelengths are used to improve visibility under mesopic vision environment, then visibility is improved, but the number of components increases

Engineering Contradiction:
ImprovevisibilityVSAvoidnumber of components
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent segments the light source into two distinct LED units: a first LED unit emitting short wavelength light (400-480nm) and a second LED unit emitting long wavelength light (610-630nm). This segmentation allows independent control of each wavelength band, improving mesopic visibility while maintaining manageable component complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the spectral parameters by selecting specific wavelength ranges for each LED unit (short wavelength 400-480nm and long wavelength 610-630nm) and controls the emission intensity of each unit independently. This parameter optimization achieves mesopic visibility improvement without requiring three separate light sources, thereby controlling component complexity

Inventive Principle:
Principle #35Parameter changes

2Reliability

If backup power supply with rechargeable battery is used to ensure continuous operation during power interruptions, then reliability is improved, but power consumption management becomes more complex

Engineering Contradiction:
Improvecontinuous operationVSAvoidpower consumption management
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic power management by enabling the control unit to switch between main power supply and backup power supply (rechargeable battery) based on power availability. During backup operation, the system dynamically adjusts the emission intensity of LED units to optimize battery life while maintaining essential lighting functions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The rechargeable battery is pre-charged during normal operation when main power is available. The control unit monitors battery charge levels in advance and prepares for seamless transition to backup power mode, ensuring continuous operation without interruption while simplifying power management through proactive energy storage

Inventive Principle:
Principle #10Preliminary action

3Use of energy by moving object

If LED light sources are used instead of fluorescent lamps or incandescent bulbs, then power consumption is reduced, but color rendering and chromatic adaptation requirements become more challenging

Engineering Contradiction:
Improvepower consumptionVSAvoidcolor rendering
Core Design Contradiction:
Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The patent optimizes the wavelength parameters of LED light sources to balance power consumption and color rendering. By selecting short wavelength LEDs (400-480nm) and long wavelength LEDs (610-630nm) with specific spectral characteristics, the system achieves efficient energy conversion while maintaining acceptable color rendering properties for mesopic vision conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies different spectral characteristics to different LED units according to their specific functions. The short wavelength LED unit targets rod cell stimulation for mesopic visibility, while the long wavelength LED unit complements the spectrum for color rendering. This localized spectral optimization allows each LED unit to perform its specific function efficiently

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 device improves visibility under mesopic conditions by activating the short wavelength LED source during power failures, reducing power consumption, and minimizing the number of components, while maintaining high color rendering and correlated color temperature, ensuring comfortable chromatic adaptation.

Implementation Method 1

a fluorescent body (23) covering a light emitting surface of the LED light source (22) and emitting yellow light

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP2685786B1Lighting device
Publication Date: 2017.09.13 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP2685786B1 patent drawingFigure 1~2
  • EP2685786B1 patent drawingFigure 3A~4
  • EP2685786B1 patent drawingFigure 5~6

AI summary

A lighting device is provided with an illumination unit (10) including two or less LED light sources (21,22). The illumination unit (10) uses the two or less LED light sources (21,22) to emit light of a short wavelength band and light of a long wavelength band. An output varying unit (38) functions to vary an output of at least the long wavelength band light. When the output varying unit (38) receives a varying signal, the output varying unit (38) functions to decrease the output of at least the long wavelength band light.