Ceramic Rear Cover Composite Structure for Lighter Electronic Housings

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Solution Overview

Problem

Ceramic materials used in electronic devices, such as mobile phones, are heavy and difficult to reduce weight while maintaining strength, especially when trying to create a thinner ceramic rear cover or middle frame that can withstand usage without compromising structural integrity.

Innovation Solution

A rear cover and middle frame design incorporating a ceramic outer housing combined with an inner housing made of a fiber-reinforced composite, where the fiber-reinforced composite provides strength and toughness, allowing for a thinner and lighter structure while maintaining the ceramic's high quality and hardness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a ceramic rear cover or middle frame is used, then high hardness and abrasion resistance are achieved, but weight increases

Engineering Contradiction:
Improvehardness and abrasion resistanceVSAvoidweight of electronic device
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The rear cover is divided into two distinct parts: a ceramic outer housing (52) providing hardness and abrasion resistance, and an inner housing (51) made of fiber-reinforced composite material providing strength support. This segmentation allows each material to perform its optimal function while reducing overall weight compared to a solid ceramic construction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure combining ceramic material and fiber-reinforced composite material. The ceramic outer housing provides surface hardness and scratch resistance, while the inner fiber-reinforced composite housing provides structural strength and toughness, achieving a weight reduction compared to solid ceramic while maintaining or improving overall mechanical performance.

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If the thickness of ceramic rear cover or middle frame is reduced, then weight is reduced, but strength cannot satisfy requirements

Engineering Contradiction:
Improveweight of electronic deviceVSAvoidstrength of ceramic rear cover or middle frame
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

By segmenting the rear cover into outer and inner housings with different materials, the design enables the outer ceramic layer to be thin (reducing weight) while the inner fiber-reinforced composite layer provides the necessary structural strength support, solving the contradiction between thickness reduction and strength maintenance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the rear cover use different materials optimized for their specific functions: the outer surface uses ceramic for hardness and scratch resistance, while the inner structure uses fiber-reinforced composite for strength and toughness. This local optimization allows thin overall design while maintaining strength requirements.

Inventive Principle:
Principle #3Local quality

3Strength

If inner structure design is made on ceramic outer housing, then high quality and hardness are implemented, but manufacturing difficulty increases due to high hardness

Engineering Contradiction:
Improvehardness and qualityVSAvoidease of inner structure design
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The segmentation of the rear cover into outer and inner housings allows the complex inner structure to be designed and manufactured in the inner housing made of fiber-reinforced composite material, which is easier to form and manufacture than ceramic. The outer ceramic housing can then be simply fitted over this pre-manufactured inner structure, significantly easing the manufacturing process while maintaining ceramic's hardness and quality on the outer surface.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4024835B1Middle frame, rear cover and preparation method therefor, and electronic device
Publication Date: 2025.03.26 HUAWEI TECH CO LTD
  • EP4024835B1 patent drawingFigure 1
  • EP4024835B1 patent drawingFigure 2
  • EP4024835B1 patent drawingFigure 3

AI summary

Embodiments of this application provide a middle frame, a rear cover, and fabrication methods thereof, and an electronic device. The electronic device may include a mobile or fixed terminal with a frame or a housing, such as a mobile phone, a tablet computer, a notebook computer, an ultra-mobile personal computer (UMPC), a handheld computer, a walkie-talkie, a netbook, a POS terminal, a personal digital assistant (PDA), an event data recorder, a wearable device, a virtual reality device, a wireless USB flash drive, a Bluetooth speaker/headset, or a vehicle-mounted device. Ceramics and fiber reinforced composite are used to form frames of a rear cover and a middle frame, to reduce thicknesses of a ceramic outer housing and a ceramic outer frame, thereby reducing a weight of the electronic device. This resolves a prior-art problem that the electronic device has a relatively large weight when a pure ceramic middle frame and a pure ceramic battery cover are used in the electronic device.