Flexible LED Lighting Module Color Calibration

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Solution Overview

Problem

Flexible LED lighting modules emit a bluer light due to the use of a flexible encapsulant, which requires calibration adjustments to correct for the color shift, particularly affecting warm and cool white LEDs, and intensity changes.

Innovation Solution

A method for calibrating flexible LED lighting elements involving multiple color LEDs and a flexible encapsulant with embedded phosphor particles, where initial calibration coefficients are adjusted to match a target color within a predefined tolerance, accounting for the color shift caused by the encapsulant, and a flexible U-shaped housing and PCB design allowing for bendability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flexible encapsulant is used in the LED lighting module, then the housing becomes flexible and bendable, but the emitted light color shifts to bluer tones requiring calibration adjustments

Engineering Contradiction:
ImproveflexibilityVSAvoidcolor accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-calibrating the LED modules during manufacturing to account for the color shift caused by the flexible encapsulant. Calibration coefficients are determined in advance and stored in memory, allowing the system to compensate for the bluer light emission without requiring real-time adjustments during use.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter of the encapsulant's optical properties by selecting materials with specific refractive indices that minimize color shift. Additionally, the calibration process adjusts the intensity parameters of individual LEDs to compensate for the encapsulant's effect on light transmission, thereby maintaining color accuracy despite the flexible material's presence.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple LEDs of different colors are used to achieve target color emission, then color versatility is improved, but calibration complexity increases due to interdependent color contributions

Engineering Contradiction:
Improvecolor rangeVSAvoidcalibration process
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the calibration process into distinct steps for different color components. The method first determines calibration coefficients for warm white LEDs, then for cool white LEDs, and finally for colored LEDs separately. This segmented approach simplifies the overall calibration complexity by breaking down the multi-color calibration into manageable sequential tasks.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs feedback mechanisms where the measured color output is continuously compared against target color values, and calibration coefficients are iteratively adjusted based on the deviation. This feedback loop ensures that the combined output of multiple LEDs converges to the desired target color, managing the complexity through systematic error correction.

Inventive Principle:
Principle #23Feedback

3Duration of action of stationary object

If calibration coefficients are stored in non-volatile memory, then calibration data is preserved, but additional memory components and reading operations increase device complexity

Engineering Contradiction:
Improvecalibration data retentionVSAvoidmemory system
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent applies self-service by having the microcontroller directly write and read calibration coefficients from non-volatile memory without requiring external calibration equipment or additional complex memory management systems. The system autonomously manages its own calibration data, simplifying the overall architecture despite the inclusion of non-volatile memory.

Inventive Principle:
Principle #25Self-service

4Adaptability or versatility

If the flexible PCB and housing are designed to bend to a 2-inch radius, then flexibility and adaptability are improved, but structural integrity and reliability may be compromised

Engineering Contradiction:
ImprovebendabilityVSAvoidstructural integrity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent employs flexible shells and thin films by using a flexible printed circuit board (PCB) and a flexible housing made from materials that can withstand repeated bending to a 2-inch radius. These flexible structures maintain electrical connectivity and structural integrity through specialized construction techniques, allowing the LED module to adapt to curved surfaces without compromising reliability.

Inventive Principle:
Principle #30Flexible shells and thin films

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 calibration method effectively adjusts for the color shift caused by the flexible encapsulant, ensuring accurate color emission and intensity correction, maintaining the desired color temperature and reducing the need for additional adjustment factors.

Implementation Method 1

An encapsulant fills a channel of the flexible housing and has a same or similar optical refractive index value as is used in the LED unit to hold phosphorous particles used for coloring of the LED

Methodology Applied
Scientific EffectOptical refraction: Refraction

Implementation Method 2

contains embedded phosphor particles used for coloring of the LED

Methodology Applied
Scientific EffectPhosphorescence: Phosphorescence

Data Source

PatentEP3557952B1Flexible LED lighting element
Publication Date: 2021.04.07 BE AEROSPACE INC
  • EP3557952B1 patent drawingFigure 1~3
  • EP3557952B1 patent drawingFigure 4A~4E
  • EP3557952B1 patent drawingFigure 5A

AI summary

A flexible LED lighting module (250) includes a flexible housing (270) and flexible PCB (260) to which LED units (500) are mounted. An encapsulant (280) fills a channel of the flexible housing (270) and has a same or similar optical refractive index value as is used in the LED unit (500) to hold phosphorous particles used for coloring of the LED. Use of the encapsulant (280) changes the color of the light ultimately emitted from the flexible LED lighting module (250), and this factor is corrected for in calibration processes associated with the flexible LED lighting module (250).