Roof Window Screening with Light-Proofing Against Reflections

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Solution Overview

Problem

Existing screening arrangements for roof windows, particularly those installed in inclined roof surfaces, suffer from light leakage due to reflections between the top casing and the guide bar, compromising light-proofing properties.

Innovation Solution

Incorporating a light-proofing element within the top casing that extends past the first outer tangent line between the roller and guide bars to block light reflections, ensuring no direct path for light to enter the interior room.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a roller assembly with separate roller bar and guide bar is used to guide the screening body, then the screening body can be guided in a well-defined plane, but light may pass between the top casing and the guide bar due to reflections

Engineering Contradiction:
Improveguiding of screening bodyVSAvoidlight leakage
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

A light-absorbing element is introduced as an intermediary component between the roller bar and guide bar. This element absorbs incident light before it can reflect off the guide bar or top casing, thereby eliminating the light leakage problem while maintaining the guiding function of the roller assembly

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The optical properties of the components are changed by introducing a light-absorbing element with specific optical parameters. This element has high light absorption capability, which changes the overall optical behavior of the roller assembly from reflective to absorptive, preventing light from entering the interior room

Inventive Principle:
Principle #35Parameter changes

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 light-proofing element effectively obstructs light from entering the interior room by blocking reflections along or above the tangent line, enhancing the light-blocking capabilities of the screening arrangement.

Implementation Method 1

a light-proofing element extending within the top casing, which is furthermore characterized in that said light-proofing element passes the first outer tangent line so as to prevent reflection of light along or above the first outer tangent line

Methodology Applied
Scientific EffectLight blocking: Absorption (EM radiation)

Data Source

PatentEP4177437B1Screening arrangement comprising a light-proofing element
Publication Date: 2025.10.08 VKR HOLDING AS
  • EP4177437B1 patent drawingFigure 1~2
  • EP4177437B1 patent drawingFigure 3
  • EP4177437B1 patent drawingFigure 4~7

AI summary

In a screening arrangement (10) for a roof window (1), a top casing (11) is configured to extend longitudinally substantially in parallel with a top member (2) of a frame structure. A screening body (12) has a screening position in which the screening body (12) substantially covers a window opening (6) of the roof window (1). A roller assembly (20) is accommodated in the top casing (11) and comprises a roller bar (21) and a guide bar (22). A first outer tangent line (T1) is defined to extend between the roller bar (21) and the guide bar (22) and substantially intersecting a periphery of the roller bar (21) and a periphery of the guide bar (22), the first outer tangent line (T1) extending on a side of the roller assembly (20) closer to a top of the top casing (11). The screening arrangement (10) further comprises a lightproofing element (30) extending within the top casing (11) and at least contacting the first outer tangent line (T1) so as to prevent reflection of light along the first outer tangent line (T1).