Foam-Injected EL Sheet Door Trim Glare Reduction

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Solution Overview

Problem

Conventional vehicle interior materials, particularly door trims, suffer from glare issues and compromised aesthetics due to complex illumination systems, which detract from the user's experience and visibility at night.

Innovation Solution

A foam-injection molding method incorporating an electro luminescence (EL) sheet, a thermoplastic elastomer foam layer, and a skin layer with adjustable transmittance, embedded with a power line and additives like fluorescent or polarizing materials to prevent exposure and enhance light emission, is used to create a soft-touch, visually appealing interior material.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a separate illumination unit is provided adjacent to a part of a door trim, then the discrimination and sense of beauty are improved, but the night view visibility is deteriorated due to glare phenomenon

Engineering Contradiction:

Improveillumination effectivenessVSAvoidglare phenomenon

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent combines the illumination function with the door trim structure itself by embedding an EL sheet within the foam-injection molded door trim, rather than using a separate illumination unit. This integration eliminates the glare problem while maintaining aesthetic illumination, as the light is diffused through the foam material and skin layer rather than emitted from a concentrated external source.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The foam layer acts as an intermediary medium between the EL sheet and the external environment. It diffuses and softens the light emitted by the EL sheet, preventing direct glare while still providing effective illumination and aesthetic effect. The skin layer further mediates the light transmission to achieve the desired visual effect without harmful glare.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Illumination intensity

If a separate illumination unit is provided, then the discrimination is improved, but the beauty is deteriorated due to complicatedness of the illumination unit

Engineering Contradiction:

ImprovediscriminationVSAvoidcomplicatedness of illumination unit

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The illumination function is merged into the door trim manufacturing process itself. The EL sheet is embedded during the foam-injection molding process, integrating multiple functions (structural support, illumination, aesthetics) into a single component rather than requiring separate illumination units and assembly steps.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The door trim structure serves multiple functions simultaneously: it provides structural support through the base material and foam layer, aesthetic appearance through the skin layer, and illumination through the embedded EL sheet. This multi-functionality eliminates the need for separate dedicated illumination components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of operation

If the skin layer is formed by foaming with TPE material, then the soft feeling is maximized, but the manufacturing precision may be compromised

Engineering Contradiction:

Improvesoft feelingVSAvoidmolding precision

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent utilizes parameter changes in the foaming process, specifically controlling the foam expansion ratio, cell structure, and material properties of the TPE foam to achieve both soft tactile properties and dimensional accuracy. By optimizing foaming parameters such as temperature, pressure, and expansion timing, the process achieves compatibility between softness and precision.

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 solution enhances the emotional quality and beauty of vehicle interiors by providing improved night visibility, soft touch, and luxurious aesthetics while preventing glare and exposure issues, thereby increasing user convenience and interior decoration quality.

Implementation Method 1

an electro luminescence (EL) sheet which is able to emit a light

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a foam layer disposed on an upper side of the EL sheet

Methodology Applied

Scientific EffectLight absorption and diffusion: Absorption (EM radiation)

Implementation Method 3

The skin layer is formed of a material capable of adjusting transmittance

Methodology Applied

Scientific EffectTransmittance adjustment:

Implementation Method 4

The additive is a fluorescent material or a polarizing material

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 5

The additive is a fluorescent material or a polarizing material

Methodology Applied

Scientific EffectPolarisation: Polarisation

Data Source

PatentUS9963067B1Structure and method of foam-injection molding including EL sheet

Publication Date: 2018.05.08 SEOYON E HWA CO LTD

AI summary

Provided is a structure of foam-injection molding including an EL sheet. The structure includes: a base material; an electro luminescence(EL) sheet which is able to emit a light, and which is disposed on an upper side of the base material; a foam layer disposed on an upper side of the EL sheet; and a skin layer disposed on an upper side of the foam layer.