Elongated LED Lamp Optical Element Bending Stress Alignment

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Solution Overview

Problem

Existing elongated LED lamps face challenges in cost-effective production and maintaining precise optical alignment due to temperature fluctuations, which can cause undesirable gaps and stresses between optical elements and the carrier bar.

Innovation Solution

An elongated LED lamp design featuring an optical element held under bending stress, with a slight curvature that is eliminated upon assembly, using a screw connecting element to ensure precise alignment and secure positioning, and a latching connection to prevent relative movement due to temperature changes, allowing for precise light influencing and cost-effective manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the optical element is rigidly fixed to the carrier element, then the alignment is stable, but temperature fluctuations cause undesirable gaps and stresses

Engineering Contradiction:
Improvealignment stabilityVSAvoidgaps and stresses from temperature fluctuations
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a curved mounting surface on the optical element that changes its effective shape under bending stress. This parameter change allows the optical element to adapt to thermal expansion and contraction, maintaining contact and alignment stability while accommodating temperature-induced dimensional changes without creating gaps or harmful stresses.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The mounting design allows the optical element to dynamically adjust its position and shape in response to temperature changes. The curved surface enables controlled deformation that maintains optimal alignment conditions across varying thermal conditions, transforming a static rigid connection into a dynamically adaptive one.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the optical element is held under bending stress with curved mounting surface, then alignment precision is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvealignment precisionVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies curvature to the mounting surface of the optical element, which is then bent during assembly to achieve precise alignment. This curvature approach allows for fine-tuning of the optical element's position and orientation, achieving high alignment precision while the curvature itself can be integrated into standard manufacturing processes like injection molding.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Object-affected harmful factors

If the optical element is not fixed at end regions in longitudinal direction, then temperature-induced stresses are reduced, but alignment precision may deteriorate

Engineering Contradiction:
Improvetemperature-induced stressesVSAvoidalignment precision
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The mounting system is segmented into different zones: the curved mounting surface area that allows controlled deformation for stress relief, and the end regions that provide positional constraints. This segmentation enables the optical element to expand and contract along its length without generating harmful stresses, while still maintaining precise alignment through the curved surface mechanism.

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

The design achieves precise alignment and secure positioning of the optical element relative to the LED light source, preventing gaps and stresses, while enabling cost-effective production and maintaining optical accuracy even with long optical elements exceeding 30 cm in length.

Implementation Method 1

the optical element is arranged so as to be held on the carrier element under a bending stress

Methodology Applied
Scientific EffectBending stress: Deformation

Implementation Method 2

the at least one connecting element exerts a force on the optical element that acts perpendicularly to the longitudinal axis

Methodology Applied
Scientific EffectForce application: Force

Data Source

PatentEP3006817B1Elongated LED lamp
Publication Date: 2018.05.23 ZUMTOBEL LIGHTING GMBH
  • EP3006817B1 patent drawingFigure 1
  • EP3006817B1 patent drawingFigure 2
  • EP3006817B1 patent drawingFigure 3

AI summary

A luminaire has an elongated support element (1), an LED light source (5) arranged on the support element (1) for generating light, and an elongated optical element (3) extending along a longitudinal axis (L) and arranged parallel to the support element (1) for influencing the light, wherein the optical element (3) is held on the support element (1) under bending stress.