Laser Beam-Combining Optical Device with Reflective Element

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Solution Overview

Problem

Current laser beam-combining technologies face challenges in achieving high output power and small focus spot size due to differences in laser beam path lengths and aberration issues, particularly when combining light from multiple laser elements, which complicates the optical system design and increases costs.

Innovation Solution

A laser beam-combining optical device that uses a reflective element to adjust the optical axis of laser beams from semiconductor laser arrays, allowing them to be focused on a single point with equal beam radii, eliminating the need for adjacent array arrangement and enabling flexible placement, and includes a condenser unit with a lens array and condenser lens for efficient beam focusing and aberration correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If light beams from multiple laser elements are combined using different path lengths to a condenser lens, then high output power can be achieved, but the radii of the light beams at the condenser lens location differ, making it difficult to obtain a sufficiently small focus point

Engineering Contradiction:
Improveoutput powerVSAvoidfocus spot size
Core Design Contradiction:
PowerVSManufacturing precision

Solution Approach 1:

The patent changes the optical path length parameter by introducing a reflective element to delay one of the laser beams, ensuring that all beams have equal path lengths to the condenser lens. This parameter adjustment allows the beams to maintain equal radii at the focal point, achieving both high output power and small focus spot size simultaneously.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a single multi-emitter laser is used to combine light rays, then the configuration is simplified, but it creates difficulties in combining outputs of multiple multi-emitter lasers

Engineering Contradiction:
Improveoptical system configurationVSAvoidcombining capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent designs an optical system that can universally handle both single multi-emitter laser configurations and multiple multi-emitter laser combinations. The reflective element and equal path length design create a versatile system that adapts to different laser array configurations, enabling flexible scaling from single to multiple laser sources without fundamental redesign.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Power

If polarization members and condenser lenses are used to align and combine laser beams, then beam combination is achieved, but the system complexity increases and aberration correction becomes difficult

Engineering Contradiction:
Improvebeam combination efficiencyVSAvoidoptical system complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent extracts the beam combination function from a complex system involving polarization members and multiple optical elements, simplifying it to a fundamental reflective element-based approach. By removing unnecessary polarization components and focusing on equal path length control through reflection, the system achieves beam combination with reduced complexity and improved aberration characteristics.

Inventive Principle:
Principle #2Taking out (Extraction)

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 high-density, high-power laser output with reduced focus spot size and increased flexibility in array placement, simplifying the optical system and reducing aberration, thus enhancing the efficiency and cost-effectiveness of laser beam combination.

Implementation Method 1

a reflective element configured to reflect a laser light beam emitted from at least one semiconductor laser array of the plurality of semiconductor laser arrays

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

When laser light beams emitted from respective ones of the plurality of semiconductor laser arrays are focused on a single focus point

Methodology Applied
Scientific EffectFocusing: Focusing

Data Source

PatentEP2908517B1Laser beam-combining optical device
Publication Date: 2019.12.25 MITSUBISHI ELECTRIC CORP
  • EP2908517B1 patent drawingFigure 1~2B
  • EP2908517B1 patent drawingFigure 3~4
  • EP2908517B1 patent drawingFigure 5~6

AI summary

A laser beam-combining optical device (100) according to the present invention includes a plurality of semiconductor laser arrays (10a, 10b, 10c), and a reflective element (11b, 11c) that reflects a laser light beam emitted from at least one semiconductor laser array (10b, 10c) of the plurality of semiconductor laser arrays (10a, 10b, 10c). When laser light beams emitted from respective ones of the plurality of semiconductor laser arrays (10a, 10b, 10c) are focused on a single focus point (14), the laser light beam emitted from the at least one semiconductor laser array (10b, 10c) is reflected by the reflective element (11b, 11c), and is then focused on the focus point (14).