Encoded Marking in Chemically Strengthened Glass

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Solution Overview

Problem

Conventional marking techniques on glass members for electronic devices are prone to damage or alteration during chemical strengthening processes, and surface markings can be obscured or difficult to read without disassembling the device.

Innovation Solution

The implementation of encoded markings formed within the bulk of chemically strengthened glass using laser techniques, which are positioned between the upper and lower surfaces and remain visible through optical magnification, allowing for unique identifiers to be encoded and read without affecting the glass's strength or visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If surface markings are applied to glass members using conventional techniques, then markings can be initially formed on the glass surface, but the markings are damaged or altered during chemical strengthening processes and become difficult to read

Engineering Contradiction:

Improvemarking durabilityVSAvoidmarking readability

Core Design Contradiction:

ReliabilityVSDifficulty of detecting and measuring

Solution Approach 1:

The encoded marking is formed within the bulk of the glass member before the chemical strengthening process is applied. This preliminary action ensures the marking is established in a stable position that will not be damaged or altered by subsequent chemical strengthening, thereby maintaining both durability and readability

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The marking transitions from a surface-level two-dimensional marking to a three-dimensional marking embedded within the bulk of the glass. This dimensional change allows the marking to survive chemical strengthening while remaining readable through optical magnification from the glass surface

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If encoded markings are formed within the bulk of the glass member, then the markings survive chemical strengthening operations, but the markings require optical magnification apparatus to be readable

Engineering Contradiction:

Improvemarking survival during strengtheningVSAvoidreading apparatus complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The marking is pre-formed within the glass bulk at a controlled size (3-10 microns per mark) before strengthening, ensuring it survives the chemical process while maintaining a scale that can be read with standard optical magnification equipment

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The laser forming process creates optical contrast within the glass bulk through refractive index changes or absorption characteristics, making the encoded marking detectable by optical magnification apparatus without requiring additional materials or complex reading mechanisms

Inventive Principle:

Principle #32Color changes

3Loss of information

If laser techniques are used to form markings within the glass bulk, then unique identifiers can be encoded and preserved, but the manufacturing process becomes more complex

Engineering Contradiction:

Improveinformation retentionVSAvoidmanufacturing process simplicity

Core Design Contradiction:

Loss of informationVSEase of manufacture

Solution Approach 1:

The mechanical process of applying surface markings is replaced with laser-based energy delivery that forms markings within the glass bulk. This substitution enables permanent encoding of unique identifiers and manufacturing information that survives chemical strengthening, despite requiring more sophisticated equipment

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The laser parameters (power, pulse duration, wavelength, scanning speed) are precisely controlled to create marks of specific size (3-10 microns) and depth within the glass, optimizing both the survival of the marking during strengthening and its readability while maintaining manufacturing efficiency

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 encoded markings survive chemical strengthening operations and remain readable, providing a secure and non-invasive method to track glass members and maintain information about manufacturing processes without damaging the device.

Implementation Method 1

laser forming, along an interior of a glass member, an encoded marking

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

chemically strengthened glass member

Methodology Applied

Scientific EffectIon exchange: Ion Exchange

Data Source

PatentUS11299421B2Electronic device enclosure with a glass member having an internal encoded marking

Publication Date: 2022.04.12 APPLE INC

AI summary

An electronic device may include a housing, a display positioned at least partially within the housing, a cover assembly coupled to the housing and comprising a chemically strengthened glass member, and an encoded marking formed within the chemically strengthened glass member between an upper surface and a lower surface of the chemically strengthened glass member. The encoded marking may include an array of marks, each mark of the array of marks having a dimension between about 3 microns and about 10 microns and set apart from an adjacent mark by an unmarked area of the chemically strengthened glass member. Each mark may represent a bit of information in a binary number system. The encoded marking may be readable, by an optical magnification apparatus, through the upper surface.