Afocal Beam Relay for Laser Scanning

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current pupil relay optics for 2-D beam scanning fail to meet requirements of low aberration, large deflection angles, phase preservation, large pupil size, afocality, color correction, low cost, and reduced size, making them unsuitable for laser scanning applications.

Innovation Solution

An afocal beam relay system using first and second primary concave reflective surfaces and first and second secondary convex toroidal reflective surfaces, with aspheric corrector elements to relay a decentered entrance pupil to a decentered exit pupil, preserving the phase of the beam wavefront and handling large deflection angles and pupil sizes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional pupil relay optics are used for 2-D beam scanning, then the system can achieve basic beam relaying function, but the numerical aperture and size requirements of the scan lens become excessively large

Engineering Contradiction:

Improvescan lens requirementsVSAvoidscan lens aperture size

Core Design Contradiction:

Ease of manufactureVSArea of stationary object

Solution Approach 1:

The optical system is divided into multiple functional components: a beam relay system with mirrors and lenses to manage beam path, and a separate scan lens for focusing. This segmentation allows each component to be optimized independently, with the beam relay handling beam transport and the scan lens handling focusing, thereby reducing the aperture size requirements of the scan lens.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A beam relay system acts as an intermediary between the beam source and the scan lens. This relay system includes optical elements that redirect and condition the beam, serving as a mediator that reduces the effective aperture requirements of the subsequent scan lens while maintaining beam quality and scanning capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If galvo mirrors are positioned close to and equidistant from the entrance pupil to accommodate beam displacements, then the mirrors can be positioned for optimal deflection, but the scan lens must have a larger aperture to accommodate beam displacements

Engineering Contradiction:

Improvemirror positioning flexibilityVSAvoidscan lens aperture

Core Design Contradiction:

Ease of operationVSArea of stationary object

Solution Approach 1:

The system introduces an additional optical dimension by using a beam relay with mirrors positioned at specific locations. The first mirror is positioned at a first location and the second mirror at a second location, creating a multi-dimensional beam path that manages beam displacement without requiring the scan lens to accommodate all displacements directly, thus reducing the required aperture size.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If a pre-objective scanning system is used with multiple mirrors, then the system can achieve 2-D beam scanning capability, but the design becomes more complex and the scan lens requires higher numerical aperture

Engineering Contradiction:

Improve2-D scanning capabilityVSAvoidoptical system design

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The beam relay system is designed to perform multiple functions: it relays the beam from the first mirror to the second mirror, manages beam displacements in both X and Y directions, and prepares the beam for the scan lens. This multi-functionality reduces the need for additional separate components, thereby managing system complexity while maintaining 2-D scanning capability.

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

The solution effectively reduces the numerical aperture and size requirements of the scan lens, preserves beam quality, and is capable of handling large scan angles while maintaining low aberrations and cost-effectiveness, making it suitable for laser scanning systems.

Implementation Method 1

first and second primary concave reflective surfaces and first and second secondary convex toroidal reflective surfaces

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

aspheric corrector elements to relay a decentered entrance pupil to a decentered exit pupil, preserving the phase of the beam wavefront

Methodology Applied

Scientific EffectAspheric correction:

Implementation Method 3

The directed beam of light between the first and second secondary convex mirrors is collimated in one direction and focused in mid air in an orthogonal direction

Methodology Applied

Scientific EffectOptical focusing and collimation: Focusing

Data Source

PatentUS8531750B2Afocal beam relay

Publication Date: 2013.09.10 KESSLER OPTICS & PHOTONICS SOLUTIONS

AI summary

An afocal beam relay has first and second primary concave reflective surfaces and first and second secondary convex toroidal reflective surfaces. The centers of curvature of each of the first and second primary reflective surfaces and first and second secondary reflective surfaces lie on an axis. The first and second secondary convex reflective surfaces face toward the first and second primary concave reflective surfaces and are disposed to relay a decentered entrance pupil to a decentered exit pupil. An aspheric corrector element is disposed in the path of an input beam of light that is directed by the primary and secondary surfaces to the decentered entrance pupil. The directed beam of light between the first and second secondary convex mirrors is collimated in one direction and focused in mid air in an orthogonal direction.