Laser Assembly Spacer Structure for Eutectic Bond Gap Control

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Solution Overview

Problem

Existing laser assemblies for XR glasses face challenges in maintaining predetermined gaps between laser element bases and optical waveguiding substrates, which can lead to issues like metal leakage and device failure due to improper bonding.

Innovation Solution

The laser assembly incorporates spacer layers and metal laminate films with specific metal compositions, such as Sn and Au, to maintain predetermined gaps and ensure eutectic bonding between the laser element bases and the optical waveguiding substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal films are melted at high temperature to form metal bonds, then bonding strength is improved, but melted metal may leak out through voids causing device failure

Engineering Contradiction:

Improvebonding strengthVSAvoiddevice reliability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

A spacer layer is introduced as an intermediary component between the laser element base and the optical waveguiding substrate. This spacer layer fills voids and prevents melted metal from leaking out during high-temperature bonding, while maintaining accurate alignment through its positioning structure

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The bonding structure uses a composite approach combining spacer layer material with metal bonding materials. The spacer layer material is selected to be compatible with both the metal films and the substrate, creating a multi-material bonding system that achieves both strong bonding and leakage prevention

Inventive Principle:

Principle #40Composite materials

2Device complexity

If adhesive is used for bonding, then device complexity is reduced, but bonding strength decreases and temperature dependency increases

Engineering Contradiction:

Improvebonding structure complexityVSAvoidbonding strength

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The patent replaces adhesive-based chemical bonding with metal-based eutectic bonding. This substitution eliminates the need for organic adhesives and their associated temperature dependencies, achieving superior bonding strength through metallurgical bonding mechanisms

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Manufacturing precision

If flat bonding surfaces are used, then manufacturing precision is improved, but melted metal flows more easily causing leakage

Engineering Contradiction:

Improvealignment precisionVSAvoidmetal leakage

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The spacer layer acts as a mediator that addresses the harmful effect of metal flow on flat surfaces. By providing a structured interface with controlled void filling, it prevents metal leakage while preserving the alignment advantages of flat bonding surfaces

Inventive Principle:

Principle #24Intermediary (Mediator)

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

This configuration effectively prevents metal leakage and maintains the integrity of the bonding, ensuring reliable performance and extended lifespan of the laser assembly in XR glasses.

Implementation Method 1

metal laminate films which bond the bonding surfaces of the plurality of laser element bases and the bonding surface of the optical waveguiding substrate. The plurality of metal laminate films respectively have a plurality of first metal films and second metal films that are disposed on the bonding surfaces of the plurality of laser element bases and made of metals capable of being eutectic with metals constituting the first metal films

Methodology Applied

Scientific EffectEutectic bonding: Welding

Implementation Method 2

a plurality of spacer layers which are disposed away from each other at positions respectively corresponding to the plurality of laser element bases on the bonding surface of the optical waveguiding substrate

Methodology Applied

Scientific EffectPhysical spacing: Physical Containment

Data Source

PatentUS20250155658A1Laser assembly and method for manufacturing same, laser module, optical engine, and XR glasses

Publication Date: 2025.05.15 TDK CORP

AI summary

A laser assembly of the present invention includes a plurality of laser element bases in which laser elements are installed on main surfaces, an optical waveguiding substrate in which an optical waveguiding layer is provided on a main surface, a plurality of spacer layers which are disposed away from each other at positions corresponding to the bases on a bonding surface of the substrate, and a plurality of metal laminate films which bond bonding surfaces of the plurality of laser element bases and the bonding surface of the optical waveguiding substrate. The plurality of metal laminate films are respectively disposed on the plurality of spacer layers and have a plurality of first metal films and second metal films that are disposed on the bonding surfaces of the plurality of laser element bases and made of metals capable of being eutectic with metals constituting the first metal films.