Flexible Lighting Device Thermal Elongation Management

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Solution Overview

Problem

Flexible lighting devices with embedded light engines face instability during temperature curing processes, leading to waving or twisting issues due to differing thermal elongations between the module and extruded polymeric profiles, affecting lamination accuracy and positioning.

Innovation Solution

A channel-shaped profiled body with a light-permeable central portion and light-impermeable lateral inserts, featuring undercuts to securely house and position the light engine, allows for sliding to absorb thermal elongations, preventing warping and ensuring accurate alignment through the use of sealing masses and a controlled curing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If temperature curing is applied to bond the flexible lighting module to the extruded profile, then bonding strength is improved, but thermal elongation differences cause waving and twisting

Engineering Contradiction:

Improvebonding strengthVSAvoiddimensional stability

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

A tape is introduced as an intermediary element between the flexible lighting module and the extruded profile. This tape serves as a mediator that absorbs differential thermal elongation during curing, preventing waving and twisting while maintaining bonding strength. The tape is specifically positioned at critical locations where dimensional instability would occur.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The solution explicitly addresses thermal expansion by using a tape adapted to absorb different thermal elongations of the flexible lighting module and the extruded profile during temperature curing. The tape's material properties are selected to accommodate the differential expansion between the two components.

Inventive Principle:

Principle #37Thermal expansion

2Ease of manufacture

If the flexible lighting module is laminated onto the extruded profile, then assembly is achieved, but positioning accuracy deteriorates due to waving

Engineering Contradiction:

ImproveassemblyVSAvoidpositioning accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The tape acts as a mediator that maintains dimensional stability during lamination, thereby preserving positioning accuracy. By preventing waving and twisting, the tape ensures that the flexible lighting module remains properly aligned with the extruded profile throughout the assembly process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The tape is applied to the assembly before the lamination process begins. This preliminary action of placing the tape prevents dimensional instability from occurring during subsequent heating and bonding operations, ensuring positioning accuracy is maintained throughout manufacturing.

Inventive Principle:

Principle #10Preliminary action

3Stability of the object's composition

If the module length is reduced below the curing oven length, then thermal elongation stability is improved through sliding, but productivity decreases

Engineering Contradiction:

Improvethermal elongation stabilityVSAvoidmanufacturing efficiency

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

The tape is extracted or removed after serving its purpose during curing. It performs the function of absorbing thermal elongation differences only during the critical curing process, then is removed to restore full functionality and flexibility to the lighting module without permanently compromising productivity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The solution uses thermal expansion principles to allow the module to maintain standard lengths by accommodating expansion through the tape during curing, rather than reducing module length. This maintains productivity while achieving thermal stability.

Inventive Principle:

Principle #37Thermal expansion

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 solution effectively prevents waving and twisting during curing, ensuring precise positioning and stable bonding of the flexible lighting device with the extruded profile, maintaining light output performance while accommodating thermal expansion.

Implementation Method 1

the tape being adapted to absorb the different thermal elongations while curing

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

a liquid transparent polymer which is subsequently cured

Methodology Applied

Scientific EffectCuring: Photopolymerisation

Data Source

PatentUS10054292B2Lighting device and method of manufacturing it

Publication Date: 2018.08.21 OPTOTRONIC GMBH

AI summary

In various embodiments, a lighting device is provided. The lighting device includes a channel-shaped elongate profiled body having a central or web portion and two side portions sidewise of the web portion, a profiled body having mutually opposed undercuts opening inwardly of the channel shape of profiled body, and a light radiation source assembly including an elongate support board carrying one or more light radiation sources, e.g. LED sources, the support board having longitudinal sides extending into the said undercuts, wherein the light radiation source assembly is retained by the channel-shaped profiled body.