Segmented Display Border Overmolding to Reduce Glass Stress

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Solution Overview

Problem

Conventional electronic devices with flat display covers and reduced bezels face manufacturing stress and potential damage due to abrupt corners and material contraction, leading to increased risk of fractures and breakage.

Innovation Solution

A segmented border portion is applied to a planar body panel in two stages, using materials with different properties to alleviate stress from material contraction during cooling and curing, enhancing durability and aesthetics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a continuous border material is applied around the display cover to create curved edges, then aesthetic appearance and user comfort are improved, but stress and potential damage to the display cover increase due to material contraction during manufacturing and device lifetime

Engineering Contradiction:
Improvecurved border appearanceVSAvoiddisplay cover integrity
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The border is divided into multiple discrete segments rather than being continuous. Each segment is separately positioned and attached to the display cover, allowing independent stress management. The segments create gaps that prevent continuous stress transmission around the entire display cover perimeter, thereby reducing the risk of cracks and damage while maintaining the curved aesthetic appearance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the border are treated differently through segmentation. Specific high-stress areas (such as corners and edges) can have different segment configurations, spacing, or attachment methods compared to other regions. This allows optimization of stress distribution locally while maintaining overall curved appearance, addressing the specific vulnerability points where cracks are most likely to initiate.

Inventive Principle:
Principle #3Local quality

2Weight of moving object

If the bezel is reduced to make electronic devices smaller and lighter, then device size and weight are improved, but the risk of damage to the display cover increases due to reduced structural support

Engineering Contradiction:
Improvedevice weightVSAvoiddisplay cover protection
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The segmented border structure provides structural support through distributed attachment points rather than requiring a continuous thick bezel. Each segment acts as an independent support element, collectively providing sufficient mechanical reinforcement to protect the display cover even when the overall bezel width is minimized. This enables lightweight design while maintaining display cover integrity.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If a second border material is applied to create smooth curved borders, then user comfort and aesthetics are improved, but manufacturing complexity and stress introduction increase

Engineering Contradiction:
Improveuser comfortVSAvoidmanufacturing process complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The border is implemented as separate segments that can be manufactured independently and then positioned around the display cover. This segmentation simplifies the manufacturing process by allowing parallel production of border segments, easier handling and positioning, and reduced complexity in the molding and assembly processes compared to creating a single continuous curved border structure.

Inventive Principle:
Principle #1Segmentation

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 segmented border portion reduces compressive forces on the body panel, allowing for larger and thinner designs with improved comfort and reduced risk of fractures, while maintaining a seamless appearance.

Implementation Method 1

contraction of the second material related to cooling and/or curing of the second material

Methodology Applied
Scientific EffectThermal contraction: Thermal Contraction

Data Source

PatentEP4150432B1Systems and methods for overmolding on electronic device surfaces
Publication Date: 2025.09.10 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP4150432B1 patent drawingFigure 1-1
  • EP4150432B1 patent drawingFigure 1-2
  • EP4150432B1 patent drawingFigure 2

AI summary

An electronic device includes a display with a glass planar portion and a second material position at an outer edge of the glass planar portion. The glass planar portion defines a majority of a display surface of the display, and the second material is molded to the outer edge of the glass planar portion and defines at least part of a border portion. The second material is curved in a direction perpendicular to the display surface. The second material is composed of a first plurality of segments and a second plurality of segments. Each segment of the second plurality of segments is interposed between adjacent segments of the first plurality of segments, and the first plurality of segments interlock with the second plurality of segments.