Electronic Device Casing Undercut Bonding

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Solution Overview

Problem

Existing methods for bonding metal and plastic parts in electronic device casings, such as insert molding, face challenges with achieving strong bonding forces and preventing light leakage, while being costly and time-consuming, particularly with the use of Nano Molding Technology.

Innovation Solution

Incorporating an undercut feature on the metallic layer, which allows for improved z-direction constraint and bonding of moldable materials, replacing the need for Nano Molding Technology, and enhancing the bonding force between metallic and plastic parts, while also addressing light leakage issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If Nano Molding Technology is used to bond metal and plastic parts, then bonding force is improved, but manufacturing cost and process cycle time increase

Engineering Contradiction:

Improvebonding forceVSAvoidprocess cycle time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

An undercut feature is pre-formed on the metallic layer before the moldable material is applied. This preliminary structural feature provides immediate mechanical interlocking capability, eliminating the need for subsequent Nano Molding Treatment and reducing the overall process cycle time while maintaining strong bonding force.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent extracts and eliminates the Nano Molding Treatment step from the manufacturing process by replacing it with a purely mechanical interlocking solution through the undercut feature. This removes the complex chemical treatment process while achieving the same bonding objective through geometric design alone.

Inventive Principle:

Principle #2Taking out (Extraction)

2Strength

If Nano Molding Technology is used to bond metal and plastic parts, then bonding force is improved, but manufacturing cost increases

Engineering Contradiction:

Improvebonding forceVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The undercut feature provides a simple, cost-effective mechanical solution that replaces expensive Nano Molding Treatment. The geometric feature can be easily formed during metal fabrication using conventional processes, significantly reducing manufacturing costs while achieving sufficient bonding strength.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Strength

If insert molding is used to bond metal and plastic parts, then bonding is achieved, but light leakage occurs

Engineering Contradiction:

Improvebonding forceVSAvoidlight leakage

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The undercut feature is pre-formed with optimized geometry that creates both mechanical interlocking for bonding and a light-blocking structure. This preliminary design simultaneously addresses both bonding strength and light leakage prevention without requiring additional sealing components or processes.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP3504946B1Casings of electronic devices

Publication Date: 2022.08.10 HEWLETT PACKARD DEVELOPMENT COMPANY LP

Figure 1A~1B
Figure 2A~2B
Figure 3A~3B

AI summary

In one example, a casing of an electronic device is disclosed which includes a metallic housing and a moldable material. The metallic housing may have a first surface and a second surface opposite to the first surface. The first surface may include an undercut physically contacting the second surface. The moldable material may be insert molded in the undercut of the metallic housing.