Elastic Compensator for Laser Diode Mounting on Heat Sink

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Solution Overview

Problem

Existing methods for mounting laser diodes on heat sinks often fail to provide a uniformly distributed holding force, leading to potential tilting and thermal expansion issues, which can impair the functionality and longevity of the laser diode.

Innovation Solution

A method involving a laser diode with a housing flange and an elastic compensating element, such as a stamped sheet metal part with spring tongues, is used to distribute the holding force evenly across the circumference, ensuring a constant contact pressure and compensating for component tolerances and thermal expansions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a large number of screws (at least four) are arranged around the circumference of the laser diode to provide sufficient holding force, then the holding force between the holding plate and the heat sink is sufficient, but the force distribution between the retaining plate and the flange becomes non-uniform, causing the laser diode to tilt

Engineering Contradiction:
Improveholding forceVSAvoidtilting
Core Design Contradiction:
ForceVSStability of the object's composition

Solution Approach 1:

An elastic compensation element is introduced as an intermediary between the holding plate and the laser diode flange. This elastic element distributes the holding force uniformly across the flange surface, preventing tilting while maintaining sufficient total holding force. The elastic material acts as a mediator that transforms the concentrated screw forces into a distributed uniform pressure field.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the physical state of the compensation element from rigid to elastic, allowing it to deform and distribute forces uniformly. By selecting appropriate elastic material properties and geometric parameters (thickness, diameter, elasticity modulus), the system achieves uniform force distribution that prevents laser diode tilting while maintaining adequate holding force.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If component tolerances and thermal expansions are not compensated for, then the assembly is simpler, but the holding force becomes non-constant at high and low temperature load cases, impairing laser diode functionality

Engineering Contradiction:
Improveconstant holding forceVSAvoidcompensation mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The elastic compensation element is specifically designed to accommodate thermal expansion and contraction of the laser diode and heat sink components. As temperature varies, the elastic element deforms elastically to maintain constant contact pressure, compensating for dimensional changes in the metal components without requiring complex active control mechanisms.

Inventive Principle:
Principle #37Thermal expansion

Solution Approach 2:

The elastic compensation element serves as a pre-designed cushioning mechanism that anticipates and compensates for both manufacturing tolerances and thermal effects. By incorporating this elastic element from the beginning of the design, the system proactively handles variability in component dimensions and temperature-induced expansions, ensuring reliable constant holding force throughout the operating range.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Force

If multiple screws are used to secure the laser diode, then the holding force is sufficient, but the assembly effort and manufacturing complexity increase

Engineering Contradiction:
Improveholding forceVSAvoidassembly effort
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

The elastic compensation element serves as a mediator that enables the use of fewer screws (reducing assembly complexity) while maintaining sufficient holding force. The elastic element distributes the force from fewer screw connections uniformly across the flange, achieving both force adequacy and manufacturing simplicity simultaneously.

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 solution provides a secure, even contact pressure between the laser diode and the heat sink, preventing tilting and ensuring reliable operation across varying temperature conditions with fewer screws required, reducing assembly effort and maintaining performance.

Implementation Method 1

an elastic compensation element is arranged between the holding element and the upper side of the flange of the housing of the laser diode

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a laser diode must be mounted on a heat sink, via which heat is dissipated from the laser diode and the operating temperature of the laser diode is reduced

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3386042B1Method for mounting a laser diode on a heat sink, light emitting unit mounted using this method and motor vehicle headlamp with such a light emitting unit
Publication Date: 2020.10.28 MARELLI GERMANY GMBH
  • EP3386042B1 patent drawingFigure 1
  • EP3386042B1 patent drawingFigure 2
  • EP3386042B1 patent drawingFigure 3

AI summary

The invention relates to a method for mounting a laser diode (12) on a heat sink (18), wherein the laser diode (12) has a housing (14) with a flange (16) extending over an outer circumferential surface of the housing (14). The laser diode (12) is placed in or onto a mounting position (18a) of the heat sink (18), a retaining element (20) encompassing at least part of the laser diode (12) is placed onto it from a side of the laser diode (12) facing away from the heat sink (18), the retaining element (20) being supported at least indirectly on a top surface of the flange (16), and the retaining element (20) being attached to the heat sink (18). It is proposed that an elastic compensating element (24) be arranged between the retaining element (20) and the top surface of the flange (16) of the housing (14) of the laser diode (12).