Aspherical Mirror Laser Beam Shaping for Compact Projection

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Solution Overview

Problem

Existing projection systems using laser diodes face challenges in transforming Gaussian beam profiles into homogenous or specific shapes like top-hat profiles, requiring complex lens arrangements that are bulky, costly, and temperature-sensitive, limiting their integration in compact mobile devices.

Innovation Solution

A projection system with an optical arrangement that uses an aspherically curved reflective surface to transform inhomogeneous laser radiation into a homogenous top-hat beam profile, minimizing the number of optical components and avoiding the need for anti-reflective coatings, while maintaining stability across a broad temperature range and wavelength range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If lens arrangements are used to transform Gaussian beam profiles into top-hat profiles, then beam profile transformation is achieved, but device complexity and size increase

Engineering Contradiction:

Improvebeam profileVSAvoidoptical components

Core Design Contradiction:

ShapeVSDevice complexity

Solution Approach 1:

The patent employs an aspherically curved reflective surface instead of traditional lens arrangements. This curved mirror transforms the Gaussian beam profile into a top-hat profile through reflection, eliminating the need for multiple lenses and reducing overall system complexity while achieving the desired beam shape transformation.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

Instead of using transmissive lenses to transform the beam profile, the patent uses a reflective surface. This inversion of the approach (reflection vs. refraction) achieves the same beam transformation goal while avoiding the complexity and size issues associated with lens arrangements.

Inventive Principle:

Principle #13The other way round (Inversion)

2Object-affected harmful factors

If anti-reflective coatings are applied to lens surfaces, then scattering effects are reduced, but manufacturing cost and spectral limitations increase

Engineering Contradiction:

Improvescattering effectsVSAvoidmanufacturing cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent replaces transmissive lens elements with a reflective mirror surface. This inversion eliminates the need for anti-reflective coatings on multiple lens surfaces, thereby reducing manufacturing costs and avoiding the spectral limitations imposed by such coatings while still controlling scattering effects.

Inventive Principle:

Principle #13The other way round (Inversion)

3Volume of moving object

If plastic lenses are used in compact devices, then device size is reduced, but temperature stability deteriorates

Engineering Contradiction:

Improvedevice sizeVSAvoidoptical properties

Core Design Contradiction:

Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent replaces temperature-sensitive plastic lenses with a more stable reflective mirror surface. While mirrors may have higher initial cost, they provide superior long-term temperature stability and optical property consistency, making them suitable for compact devices that require reliability across varying thermal conditions.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Manufacturing precision

If cylindrical lens arrangements are used to adjust laser axes, then beam alignment is improved, but device complexity increases

Engineering Contradiction:

Improvebeam alignmentVSAvoidoptical components

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The aspherically curved reflective surface performs multiple functions simultaneously: it transforms the Gaussian beam profile to top-hat, aligns the laser axes, and focuses the beam. This multi-functionality eliminates the need for separate cylindrical lens arrangements, reducing device complexity while maintaining precise beam alignment.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 enables compact, robust, and efficient projection systems with stable optical properties, achieving high spectral bandwidth and uniform illumination, suitable for integration in mobile devices without the limitations of traditional lens-based systems.

Implementation Method 1

a known radiation profile of the single mode laser can be transformed by means of reflection on a curved, reflective surface into any other beam profile

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS10126557B2Projection system for generating spatially modulated laser radiation and optical arrangement for transforming laser radiation

Publication Date: 2018.11.13 JABIL OPTICS GERMANY GMBH

AI summary

Described is an arrangement for the transformation of laser radiation. A projection system for generating spatially modulated laser radiation includes an optical arrangement for transforming laser radiation, a field lens, a spatial light modulator and a projection arrangement. By means of the optical arrangement, incidental laser radiation in a first direction (E) is reflected on an aspherically curved, reflective surface in a second direction (R), where in a plane perpendicular to the first direction (E) the laser radiation has an inhomogeneous beam profile (GB1, G2) with a first beam axis (A) and a second beams axis (B) perpendicular to the latter, and the aspherical curvature is designed, during the reflection on the reflective surface, to transform the inhomogeneous beam profile of the laser radiation for the first beam axis (A) and/or the second beam axis (B) respectively into a homogenous top-hat beam profile (H).