Perimeter Light Blockout Channels for Out-of-Skew Window Frames

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Solution Overview

Problem

Architectural-structure coverings, such as blinds and shades, suffer from light leakage through gaps between the covering and the window frame or wall due to imperfect fit and alignment, especially in out-of-skew frames, affecting aesthetics and functionality.

Innovation Solution

A perimeter light blockout system with a U-shaped channel and mounting extrusion or clips that minimize light leakage by adjusting to the window frame, allowing for alignment and easy installation or removal, featuring a light-absorbing inner surface to reflect light back and prevent transmission through gaps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mounting brackets are used to install the covering inside the window frame, then the covering can be securely mounted and operated, but side gaps are created between the covering and window frame that allow unwanted light to pass through

Engineering Contradiction:
Improvemounting securityVSAvoidlight leakage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A light blocking device is introduced as an intermediary element between the covering and the window frame. This device includes a channel that receives the covering and extends across the light gap to the window frame, with a light blocking member that prevents light from passing through the gap while allowing the covering to operate independently within its channel.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The light blocking device is segmented into distinct functional components: a channel portion that interfaces with the covering, a light blocking member that seals the gap, and a mounting portion that attaches to the window frame. This segmentation allows each component to perform its specific function independently while working together as a complete light blocking system.

Inventive Principle:
Principle #1Segmentation

2Ease of manufacture

If the covering is made narrower than the window opening to fit within mounting brackets, then proper installation is achieved, but side gaps are created that enable light to leak through

Engineering Contradiction:
Improveinstallation feasibilityVSAvoidlight leakage
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The light blocking device serves as a mediator that fills the space between the narrower covering and the wider window opening. The channel receives the covering while the light blocking member extends to the window frame, effectively bridging the gap without requiring the covering itself to be wider.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of increasing the width of the covering in the horizontal dimension, the solution extends vertically along the sides of the covering with light blocking channels that run from the headrail to the bottom rail, blocking light in the vertical dimension while the covering maintains its reduced horizontal width.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If complex actuators such as tilt rods and operating cords are included in the covering, then full functionality is achieved, but additional space is required that increases the side gaps

Engineering Contradiction:
Improvecovering functionalityVSAvoidlight leakage
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The light blocking channel is designed to receive and accommodate the covering with all its actuators and mechanisms. The channel provides a housing that contains the covering and its operational components, allowing tilt rods, cords, and other actuators to function within the confined space without increasing the external dimensions that would create larger gaps.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The light blocking device is designed with dynamic capabilities including adjustable mounting positions and flexible light blocking members that can adapt to the movements and operational requirements of the covering's actuators, maintaining effective light blocking while accommodating functional complexity.

Inventive Principle:
Principle #15Dynamics

4Object-affected harmful factors

If the covering is precisely aligned with the window opening, then light gaps are minimized, but the installation becomes more difficult and time-consuming

Engineering Contradiction:
Improvelight gap minimizationVSAvoidinstallation time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The light blocking device is pre-assembled with the covering during manufacturing, with channels and light blocking members positioned in advance. This preliminary action eliminates the need for precise field alignment during installation, as the light blocking components are already integrated with the covering and will function effectively regardless of minor variations in window frame alignment.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The mounting system incorporates adjustable parameters that allow the light blocking device to be positioned at different locations on the window frame. This adjustability compensates for variations in window frame dimensions and alignment, enabling effective light blocking without requiring precise measurement and alignment procedures during installation.

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

Effectively blocks unwanted light, maintains covering integrity, and facilitates proper alignment, enhancing both functionality and aesthetics by reducing light gaps and wear on the covering.

Implementation Method 1

featuring a light-absorbing inner surface to reflect light back and prevent transmission through gaps

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP3382138B1Perimeter light blockout system and corresponding method for minimizing passing light
Publication Date: 2026.03.18 HUNTER DOUGLAS INC
  • EP3382138B1 patent drawingFigure 1
  • EP3382138B1 patent drawingFigure 2
  • EP3382138B1 patent drawingFigure 3

AI summary

A perimeter light blockout system for minimizing light leakage between light gaps such as, for example, between the sides of a covering (e.g., shade) of an architectural-structure covering and the interior side surfaces of a window frame, or between the covering and the outer surface of an interior wall is disclosed. The perimeter light blockout system including a light blocking device and a mounting element for coupling the light blocking device to the interior side surface of the window frame, or the outer surface of the interior wall. The light blocking device may include rear and front channel members. The mounting element may be a mounting extrusion. Alternatively, the mounting element may be a spring clip. In use, the light blocking device may be adapted and configured so as not to contact the covering as the covering moves between extended and retracted positions. The mounting element may include a degree of adjustment so that the light blocking device may be aligned with an out-of-skew window frame.