Transparent Roof Panel Light In-Coupling with Molded Optical Adhesive

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Solution Overview

Problem

Existing transparent roof panel assemblies for vehicles face challenges in precisely shaping the light in-coupling element and efficiently minimizing the use of expensive optical adhesive, while maintaining high transparency and adaptability to the panel's contour.

Innovation Solution

The use of a mould, preferably made of transparent plastic, is applied on the light entering side of the in-coupling element during moulding, allowing for precise shaping and minimizing adhesive usage, with options for deformable sections to accommodate thermal expansion and adaptable attachment methods using adhesive tape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a mould is used to shape the in-coupling element, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvelight entering side shapeVSAvoidmould structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent employs a flexible mould that can be deformed to match the contour of the panel's interior side. This flexible mould maintains manufacturing precision for the light entering side while avoiding the need for complex rigid mould structures, thereby resolving the contradiction between precision and complexity.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The mould acts as an intermediary element between the optical adhesive and the panel interior side. It transfers the desired shape to the adhesive during curing, enabling precise shaping without requiring complex direct attachment mechanisms, thus improving precision while keeping the overall device complexity manageable.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of substance

If optical adhesive is minimized for cost reasons, then loss of substance is reduced, but manufacturing precision deteriorates

Engineering Contradiction:
Improveoptical adhesive quantityVSAvoidin-coupling element shape
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent applies optical adhesive only in the necessary amount to fill the space between the mould and the panel interior side, rather than using excessive adhesive. The mould confines the adhesive to the precise area needed, minimizing material usage while ensuring complete coverage and precise shaping, thus resolving the contradiction between reducing substance loss and maintaining manufacturing precision.

Inventive Principle:
Principle #16Partial or excessive action

3Illumination intensity

If the mould is made transparent for light transmission, then illumination intensity is improved, but strength deteriorates

Engineering Contradiction:
Improvelight transmissionVSAvoidmould structural integrity
Core Design Contradiction:
Illumination intensityVSStrength

Solution Approach 1:

The patent employs a transparent mould material that combines optical clarity with sufficient mechanical strength. By selecting appropriate transparent materials and optimizing the mould design, both light transmission and structural integrity are maintained, resolving the contradiction between illumination intensity and strength.

Inventive Principle:
Principle #40Composite materials

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 approach enables efficient light transmission, precise light shaping, and cost-effective use of optical adhesive, ensuring optimal transparency and adaptability to the vehicle roof panel's contour.

Implementation Method 1

an in-coupling element to in-couple light into the panel from the interior side of the panel, the in-coupling element being attached to the interior side of the panel and redirecting light from the at least one light source into the panel

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

redirecting light from the at least one light source into the panel

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 3

The clear plastic strip forming the mould may be provided with deformable sections along the length of the strip to compensate for thermal expansions during use of the roof panel assembly

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4474694A1A transparent roof panel assembly for a vehicle roof, and method of making it
Publication Date: 2024.12.11 INALFA ROOF SYST GROUP
  • EP4474694A1 patent drawingFigure 1~2
  • EP4474694A1 patent drawingFigure 3a~3c
  • EP4474694A1 patent drawingFigure 4a~4c

AI summary

A transparent roof panel assembly for a vehicle roof comprises a transparent panel (3) and at least one light source (8) arranged to provide light in the panel. An in-coupling element (9) to in-couple light into the panel from the interior side of the panel, is attached to the interior side of the panel and redirects light from the at least one light source (8) into the panel. The in-coupling element (9) is made at least partly from optical adhesive which is directly moulded to the interior side of the panel. The in-coupling element is bounded at least on its light entering side by a mould (11) for the optical adhesive at least during moulding of the in-coupling element.