Selective Masking of LED Circuitry to Prevent Color Shift

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Solution Overview

Problem

Flexible LED modules with sealed designs face aesthetic issues due to visible dark components and color shift phenomena, limiting the selection of LEDs and increasing costs when trying to achieve a warm white Correlated Colour Temperature (CCT) and efficient protection.

Innovation Solution

A method involving selective deposition of light-coloured and transparent elastomer materials to mask dark components while allowing light transmission, using a light-impermeable material to cover circuitry and a light-permeable material to cover LEDs, ensuring protection and minimizing color shift.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If dark-coloured components are used in LED modules, then cost and availability are improved, but aesthetic appearance deteriorates due to visible dark spots

Engineering Contradiction:
Improvecomponent availability and costVSAvoidaesthetic appearance
Core Design Contradiction:
Ease of manufactureVSShape

Solution Approach 1:

The patent applies different surface treatments to different areas: the circuit board receives a light-coloured reflective coating to mask dark components, while the LED lens maintains its original transparent or coloured appearance. This local differentiation allows dark components to be hidden where needed while preserving LED light transmission and colour characteristics.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces a light-coloured reflective coating on the circuit board surface to change the visual appearance from dark to light. This color transformation masks the dark-coloured electronic components and creates a uniform aesthetic appearance while maintaining the functionality of dark components.

Inventive Principle:
Principle #32Color changes

2Reliability

If sealing mass with different reflection coefficient is used, then protection degree is improved, but colour shift phenomenon occurs

Engineering Contradiction:
Improveprotection degreeVSAvoidemission wavelength stability
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent applies different reflective coatings to different areas: a light-coloured coating on the circuit board area and a transparent or wavelength-matched coating on the LED lens area. This ensures that the sealing mass has appropriate reflection characteristics for each location, preventing colour shift at the LED while maintaining protection.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent modifies the reflection coefficient parameter of the sealing mass by using different materials or coatings in different areas. The circuit board area uses a light-coloured coating with high reflectivity, while the LED lens area uses a transparent coating with minimal interference, thus changing the optical parameters to prevent colour shift.

Inventive Principle:
Principle #35Parameter changes

3Shape

If white silicone layer is applied to cover dark components, then aesthetic appearance is improved, but LED selection freedom is reduced

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidLED selection freedom
Core Design Contradiction:
ShapeVSAdaptability or versatility

Solution Approach 1:

The patent applies the light-coloured reflective coating selectively only on the circuit board area surrounding the LED, while leaving the LED lens area uncovered or with different treatment. This localized application improves aesthetics by masking dark components without interfering with LED light output or restricting LED selection.

Inventive Principle:
Principle #3Local quality

4Temperature

If transparent elastomer material with matched reflection coefficient is used, then colour shift is reduced, but manufacturing cost increases

Engineering Contradiction:
Improveemission wavelength stabilityVSAvoidoverall price
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The patent applies the expensive transparent elastomer material with matched reflection coefficient only in the critical LED lens area where colour shift prevention is essential, while using a simpler light-coloured coating on the circuit board area. This localized high-performance treatment reduces overall cost while maintaining wavelength stability.

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

This approach allows only LEDs to be visible, adapts to various LED types, reduces color shift, and lowers costs by enabling the use of low-cost modules while maintaining effective protection and light transmission.

Implementation Method 1

The first step consists in covering the whole board surface with a material such as white silicone, the dark (black) components being therefore covered by said silicone layer and being invisible (masked) from the outside

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

The second process step involves coating the whole board surface (already covered with the light or white silicone) with a transparent silicone, so as to favour an efficient light transmission through said transparent layer

Methodology Applied
Scientific EffectLight transmission:

Implementation Method 3

Still another solution may consist in depositing, above the transparent layer and on the whole surface of the module, a layer of diffusive particles

Methodology Applied
Scientific EffectLight diffusion: Scattering

Data Source

PatentEP3263983B1A method of producing lighting devices and corresponding device
Publication Date: 2019.05.15 OSRAM SOC RIUNITE OSRAM EDISON CLERICI
  • EP3263983B1 patent drawingFigure 1a~1f
  • EP3263983B1 patent drawingFigure 2a~2f
  • EP3263983B1 patent drawingFigure 3a~3e

AI summary

A method of producing lighting devices includes: - providing a channel-shaped housing (18), - arranging in said housing (18) a lighting module (10) with at least one electrically-powered light radiation source (14), e.g. a LED source, and circuitry (16) coupled (120) with the light radiation source(s) (14), the light radiation source(s) (14) and the circuitry (16) facing towards the opening of the channel-shaped housing (12), - providing a light-permeable cover (22, 26) that covers the light radiation source(s) (14) and leaves the associated circuitry (16) uncovered, and - providing a sealing mass of light-impermeable material (20) which masks the circuitry (16), with the light radiation emitted from the light radiation source(s) (14) being adapted to propagate through the light-permeable cover (22, 26).