Solid-State Laser Adhesive Shielding Against Thermal Stress

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Solution Overview

Problem

High thermal stress on solid-state laser arrangements due to concentrated pump radiation leads to adhesive layer degradation and mechanical deformation, causing effectiveness impairment and potential failure, especially in edge areas where the adhesive layer is not fully transparent to laser radiation.

Innovation Solution

A radiation-impermeable region is formed between the plate-shaped solid and the heat sink by applying a continuous reflective coating and optionally an absorber layer, ensuring the adhesive layer is shielded from laser radiation and maintaining effective heat conduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the adhesive layer is made thin to improve heat conduction, then thermal resistance is reduced, but the adhesive layer becomes more susceptible to radiation degradation

Engineering Contradiction:

Improvethermal resistanceVSAvoidadhesive layer stability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

A radiation-impermeable layer is introduced as an intermediary between the plate-shaped solid and the adhesive layer. This layer blocks laser radiation from reaching the adhesive, preventing radiation-induced degradation while allowing the adhesive layer to remain thin for optimal thermal conduction.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The interface between the plate-shaped solid and heat sink is segmented into functional zones: a central radiation-impermeable region for mechanical support and heat conduction, and a peripheral adhesive-free zone to prevent radiation exposure of adhesive material.

Inventive Principle:

Principle #1Segmentation

2Productivity

If pump radiation is concentrated on a specific area to increase laser power, then efficiency is improved, but thermal stress on edge areas increases causing burning and failure

Engineering Contradiction:

Improvelaser powerVSAvoidthermal stress on edge areas

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

Different regions of the plate-shaped solid are assigned different functions: a central pumped region for laser generation and a peripheral edge region with enhanced cooling and radiation shielding for thermal management. The radiation-impermeable layer specifically protects vulnerable edge areas.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The radiation-impermeable layer, which might seem to block useful pump radiation, actually converts harmful edge-area laser radiation into a beneficial protective barrier, preventing adhesive degradation and edge burning while allowing controlled pump radiation in the central region.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Strength

If the adhesive layer extends to the edge of the plate-shaped solid to ensure mechanical coupling, then mechanical strength is improved, but radiation absorption by adhesive increases causing degradation

Engineering Contradiction:

Improvemechanical couplingVSAvoidadhesive layer degradation

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The adhesive layer is extracted or removed from the peripheral edge areas of the plate-shaped solid, leaving it only in the central region where it is protected by the radiation-impermeable layer. This eliminates the harmful exposure of adhesive to laser radiation at the edges.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The radiation-impermeable layer is applied in advance to cover the entire surface including edges before adhesive application. This preliminary protective action prevents adhesive material from being exposed to radiation during subsequent operation.

Inventive Principle:

Principle #10Preliminary action

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 solution prevents adhesive layer degradation, enhances thermal stability, and maintains high laser output power by shielding the adhesive layer from radiation, allowing the solid-state laser arrangement to withstand high thermal loads and operate effectively at elevated temperatures.

Implementation Method 1

the adhesive layer is completely shielded from radiation from the plate-shaped solid by a radiation-impermeable region

Methodology Applied

Scientific EffectRadiation blocking: Absorption (EM radiation)

Data Source

PatentEP2888789B1Solid-state laser device and method for the production thereof

Publication Date: 2017.10.18 TRUMPF LASER GMBH CO KG

AI summary

The invention relates to a solid-state laser array comprising: a disk-shaped solid (2) that includes a laser-active medium; a heat sink (3); an adhesive layer (16) between a supporting surface (3a) of the heat sink (3) and the disk-shaped solid (2); and a reflective coating (4) applied to the disk-shaped solid (2) on a side (2a) facing the adhesive layer (16). The adhesive layer (16) is entirely shielded against radiation (20) from the disk-shaped solid (2) by a radiation-impermeable zone (4a) formed between the side (2a) of the disk-shaped solid (2) facing the adhesive layer (16) and the supporting surface (3a) of the heat sink (3). Such a solid-state laser array can withstand great thermal stress. The invention further relates to a method for producing such a solid-state laser array.