Resin Substrate for Pillarless Windshield with Variable Thickness

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Solution Overview

Problem

Current resin substrates for pillarless windshields are unable to achieve a balance of being large, lightweight, providing excellent visibility, and withstanding air resistance loads at high speeds, particularly at 150 km/h, while maintaining structural integrity and visibility.

Innovation Solution

A resin substrate design featuring a central viewing section with a mean thickness of 3-7 mm and thick-walled sections along the sides, where the thick-walled sections have a thickness 1.3 times or more of the mean thickness, are strategically positioned to enhance visibility and structural strength, with a specific geometry and material composition that includes optically-transparent thermoplastic resin and inorganic infrared shield materials for improved visibility and load-bearing capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a resin substrate with uniform thickness is used for pillarless windshield, then the molding process is simple and manufacturing is easy, but the substrate cannot provide sufficient strength to withstand air resistance at high speeds and causes distortion

Engineering Contradiction:
Improvemolding process simplicityVSAvoidstrength to withstand air resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent applies local quality by creating a resin substrate with non-uniform thickness distribution. Specifically, the substrate has a first region with thickness of 3-7mm and a second region with thickness of 8-15mm, where the thicker second region is positioned at the periphery to provide enhanced structural strength and resistance against air resistance at high speeds, while the thinner first region maintains adequate visibility and reduces overall weight.

Inventive Principle:
Principle #3Local quality

2Area of stationary object

If the windshield is made larger to provide excellent visibility, then the viewing area increases, but the substrate becomes more susceptible to distortion from air resistance and requires increased structural strength

Engineering Contradiction:
Improveviewing areaVSAvoidresistance to distortion
Core Design Contradiction:
Area of stationary objectVSStability of the object's composition

Solution Approach 1:

The patent resolves this contradiction by implementing local quality through strategic thickness variation. The substrate features a larger first region (3-7mm thickness) for maximum viewing area and visibility, while incorporating a thicker second region (8-15mm) at the periphery that acts as a structural reinforcement zone. This thicker peripheral region provides the necessary rigidity to resist distortion from air resistance during high-speed driving, allowing the overall windshield to be large without compromising stability.

Inventive Principle:
Principle #3Local quality

3Strength

If a thicker resin substrate is used to increase strength, then the substrate can withstand higher loads, but the weight increases and visibility may be compromised

Engineering Contradiction:
Improveload-bearing capacityVSAvoidsubstrate weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies local quality by positioning the thicker second region (8-15mm) specifically at the periphery of the substrate where structural strength is most needed to withstand aerodynamic loads. The central first region maintains a thinner profile (3-7mm) to minimize weight and optimize visibility. This localized thickness differentiation allows the substrate to achieve high load-bearing capacity where required while keeping overall weight lower than a uniformly thick substrate would provide.

Inventive Principle:
Principle #3Local quality

4Shape

If a black resin layer is added to the periphery to hide adhesive, then the aesthetic appearance improves, but good visibility is lost when adopted to pillarless windshield configuration

Engineering Contradiction:
Improveaesthetic appearanceVSAvoidvisibility
Core Design Contradiction:
ShapeVSIllumination intensity

Solution Approach 1:

The patent resolves this contradiction by applying local quality through transparent or translucent resin material selection. Instead of using opaque black resin that would block light, the substrate is made from transparent or translucent material that allows light transmission for excellent visibility. The peripheral region, while structurally thicker, maintains optical clarity, thus achieving both aesthetic appearance suitable for pillarless configurations and optimal visibility for driver safety.

Inventive Principle:
Principle #3Local quality

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 resin substrate achieves excellent visibility and high strength to withstand air resistance loads at 150 km/h, maintaining a lightweight structure and reducing distortion, while also providing improved weatherability and abrasion resistance through a unique geometric and material approach.

Implementation Method 1

a resin substrate design featuring a central viewing section with a mean thickness of 3-7 mm and thick-walled sections along the sides... that includes optically-transparent thermoplastic resin for improved visibility

Methodology Applied
Scientific EffectLight transmission: Refraction

Implementation Method 2

inorganic infrared shield materials for improved visibility and load-bearing capacity

Methodology Applied
Scientific EffectInfrared shielding: Absorption (EM radiation)

Data Source

PatentEP3636471B1Resin substrate for pillarless windshield
Publication Date: 2021.08.04 TEIJIN LTD
  • EP3636471B1 patent drawingFigure 1~3
  • EP3636471B1 patent drawingFigure 4~5c
  • EP3636471B1 patent drawingFigure 6a~7a

AI summary

Provided is a resin substrate for the pillarless windshield which is large yet light-weight and provides excellent visibility, and has further realized a high strength to withstand a load calculated based on air resistance under the driving speed of 150 km/h. The resin substrate for the pillarless windshield has the longest side (SA) fixed to car body (3), wherein the resin substrate is an uneven-thickness structure having viewing section (1) with a mean thickness (d1) of 3-7 mm and thick-walled section (2) with a thickness of 1.3 times the (d1) or more, and satisfies all requirements of following (a)-(d): (a) the resin substrate having thin-walled viewing section (1) in the center, and having thick-walled sections (2B, 2C and 2D) along total three sides of (SB, SC and SD): opposite side (SB) of the longest side (SA), and two sides (SC and SD) between the ends of the longest side (SA) and those of the opposite sides (SB) of the longest side, (b) the viewing section (1) and thick-walled section (2) being made of an optically-transparent thermoplastic resin satisfying 5% or less of a haze at 6-mm thickness measured according to JISK7105, (c) the longest side (SA) having a length (L1) of 900 mm or longer and 2000 mm or shorter, (d) the thick-walled sections (2B, 2C and 2D) having mean thicknesses (d2B, d2C and d2D) each 3.0 times or less of the d1 and an area accounting for 3-20% of the whole area of the resin substrate.