Low Inductance Laser Diode Bar Mount Using Heat Sink Electrical Connection

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Solution Overview

Problem

Existing laser diode bar mounts face limitations in pulse mode operation due to high inductance in the electrical connection circuit, leading to longer rise and fall times, which are undesirable for applications requiring fast current response, such as range-gated active imaging.

Innovation Solution

The solution involves positioning a printed circuit board driver directly onto the heat sink base adjacent to the laser bar, using a heat sink base as an electrical connection, and employing a sheet of electrically conductive material with a narrow fold to reduce loop surface area and inductance, while securing the components with clamps to maintain low inductance and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the electrical connection circuit uses traditional mount arrangements, then the connection is simple and reliable, but the inductance is high which limits fast rise and fall times in pulse mode operation

Engineering Contradiction:

Improverise and fall timeVSAvoidelectrical connection stability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The heat sink base is merged to serve dual functions: thermal management and electrical connection. The heat sink base with high thermal conductivity and low electrical resistivity forms the first electrical connection between the laser bar and driver, eliminating the need for separate electrical connection components and reducing overall circuit inductance.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The electrical connection transitions from traditional wire-based three-dimensional routing to a planar configuration where the driver is positioned directly on the heat sink base. This dimensional change reduces the loop surface area and associated inductance while maintaining connection reliability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Speed

If the driver is positioned远离 the laser bar, then the mounting is easier and more flexible, but the loop surface area increases leading to higher inductance

Engineering Contradiction:

Improvecurrent response speedVSAvoidmounting flexibility

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The heat sink base serves multiple functions simultaneously: thermal sinking, electrical connection, and mechanical mounting platform. By positioning the driver directly on the heat sink base, the design achieves both low inductance (through minimal loop area) and mounting flexibility (through the universal platform).

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

A thin, flexible electrically conductive sheet with a narrow fold is used for the second electrical connection. The fold provides elasticity to accommodate positioning variations while the narrow profile minimizes the loop surface area and associated inductance.

Inventive Principle:

Principle #30Flexible shells and thin films

3Strength

If traditional soldering methods are used to secure the driver and laser bar, then the connection is strong, but stress is induced in the laser bar causing misalignment

Engineering Contradiction:

Improveconnection strengthVSAvoidlaser bar alignment

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

Traditional soldering (thermal-mechanical bonding) is replaced with a purely mechanical clamping system. Clamps apply controlled mechanical force to secure the driver and laser bar to the heat sink base, providing strong connections without the thermal stress and misalignment risks associated with soldering.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 achieves short rise and fall times, enabling satisfactory operation in pulsed mode with currents up to 90 A, rise times below 125 ns, and low thermal resistance, while avoiding stress-induced misalignment and thermal issues.

Implementation Method 1

a heat sink base having a high thermal conductivity

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

having a low electrical resistivity and having a connection face secured in electrical contact with both the laser bar first electrical contact and the driver first electrical contact

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

The inductance value is affected by the loop surface area of the current going from the driver to the laser diode and back. One way to reduce the loop surface area is to bring the driver close to the laser bar

Methodology Applied

Scientific EffectElectrical inductance reduction through geometry optimization:

Data Source

PatentUS9031104B2Low inductance laser diode bar mount

Publication Date: 2015.05.12 OBZERV TECH

AI summary

The laser mount arrangement can have a laser bar and a driver positioned adjacent to one another and secured against a connection face of a heat sink base. The heat sink base is connected to and forms a first electrical connection between the laser bar and the driver. A second electrical connection is also provided between the laser bar and the driver opposite the heat sink base, which can be in the form of a flexible metal sheet with a narrow upward fold. This arrangement can provide a low inductance path for the current.