Lamp Reflector Spring Sealing Thermal Expansion

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Solution Overview

Problem

Long lamps with LED light sources experience temperature fluctuations, leading to uneven expansion and contraction of housing and reflector elements, causing geometric and optical misalignment, gaps, and mechanical stress, which affects light emission and is exacerbated by manufacturing tolerances.

Innovation Solution

A lamp design featuring a first and second reflector element with spring elements that contact each other under elastic tension, ensuring light-tight sealing and maintaining alignment despite temperature changes, with the first reflector element having a C-shaped spring section and the second having a further spring element for enhanced contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple reflector elements are provided along the longitudinal axis to reduce misalignment, then geometric and optical assignment is improved, but gaps form between reflector elements allowing unwanted light emission

Engineering Contradiction:
Improvegeometric and optical assignmentVSAvoidunwanted light emission through gaps
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent employs a flexible sealing element (membrane) that spans across gaps between reflector elements and at end regions. This membrane is capable of deforming elastically to maintain light-tight sealing despite relative movements caused by thermal expansion differences between the housing and reflector elements made of different materials.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sealing membrane is designed with specific elastic properties allowing it to accommodate parameter changes in dimensions due to thermal expansion. The membrane's flexibility parameter enables it to deform and maintain contact, preventing light leakage while allowing the reflector elements to expand and contract independently.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If reflector elements are butted together to eliminate gaps, then light-tight sealing is improved, but very high mechanical stresses and noise occur

Engineering Contradiction:
Improvelight leakageVSAvoidmechanical stresses
Core Design Contradiction:
Object-generated harmful factorsVSStress or pressure

Solution Approach 1:

Instead of rigid butting of reflector elements, the patent introduces a flexible membrane that provides light-tight sealing through elastic deformation. This flexible element absorbs mechanical stresses and prevents noise while maintaining optical sealing, avoiding the high stresses that would result from rigid contact between reflector elements.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The sealing membrane acts as a cushioning element between reflector elements, absorbing and distributing mechanical stresses before they can accumulate to harmful levels. This pre-compliance element prevents stress concentration and noise generation that would occur with direct rigid contact.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If a single reflector element extends over the entire lamp length, then device complexity is reduced, but unfavorable deviations in geometric and optical assignment occur due to thermal expansion differences

Engineering Contradiction:
Improvenumber of reflector elementsVSAvoidgeometric and optical assignment
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent divides the reflector system into multiple separate reflector elements arranged along the longitudinal axis of the lamp. This segmentation allows each element to expand and contract independently according to its material properties, maintaining geometric and optical alignment despite thermal fluctuations, while the sealing membrane connects these segments to prevent light leakage.

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 solution effectively prevents light leakage and maintains uniform reflector element spacing, reducing the probability of undesirable light emission and mechanical stress, even with large temperature changes and manufacturing tolerances.

Implementation Method 1

The first reflector element has a spring element on the first side area, which rests under elastic tension on the second side area in such a way that the light is prevented from passing between the first side area and the second side area

Methodology Applied
Scientific EffectElastic tension: Elasticity

Implementation Method 2

The housing consists on the one hand and the reflector elements on the other hand of different materials, the coefficient of thermal expansion of the material of the housing differing from that of the material of the reflector elements. During operation, the lamp is generally exposed to temperature fluctuations, for example due to the LED light sources heating up as a result of the current flow. The consequence of this is that the housing and the reflector elements expand or contract to different extents in the longitudinal direction

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

The first reflector element has a spring element on the first side area, which rests under elastic tension on the second side area

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3366993B1Lamp with reflector element
Publication Date: 2020.07.15 ZUMTOBEL LIGHTING GMBH
  • EP3366993B1 patent drawingFigure 1
  • EP3366993B1 patent drawingFigure 2
  • EP3366993B1 patent drawingFigure 3

AI summary

A luminaire comprises a housing (1), light sources (2) for generating light, a first reflector element (3), and a second reflector element (4) for influencing the light, wherein the reflector elements (3, 4) are arranged enclosed by the housing (1), and wherein the first reflector element (3) has a first side region (31), and the second reflector element (4) has a second side region (41), and the second side region (41) contacts the first side region (31). The first reflector element (3) further comprises a spring element (5) on the first side region (31), which is under elastic tension against the second side region (41) such that the passage of light between the first side region (31) and the second side region (41) is prevented.