Waveguide Deflection Structures for Multi-Aperture Imaging Illumination

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Solution Overview

Problem

Existing multi-aperture imaging systems face challenges in achieving high image quality with incident light illumination for laterally extended close object fields while maintaining a low overall height and avoiding interference with the imaging optics.

Innovation Solution

An optical arrangement using a waveguide with deflection structures positioned in dead zones between the fields of view of optical channels, guiding light laterally and deflecting it towards the object plane for efficient illumination, allowing for higher image quality and reduced optics height.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional flat lighting elements are used for illumination, then the illumination can be provided, but they affect the beam path in the multi-aperture imaging optics and are therefore not applicable

Engineering Contradiction:
ImproveilluminationVSAvoidbeam path interference
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The illumination function is segmented from the imaging optics by using separate light guide elements that are optically coupled to the imaging system. The light guide plate with exit pupils is positioned separately from the imaging objective, allowing illumination without direct beam path interference. This segmentation enables the illumination light to be delivered through a dedicated path that does not interfere with the imaging beam path.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A light guide plate acts as an intermediary element between the light source and the imaging objective. The light guide plate receives light from LED elements and transmits it through its exit pupils to illuminate the object plane without directly interfering with the imaging beam path. This intermediary approach allows decoupling of illumination and imaging functions while maintaining optical coupling.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If decoupling through bumps or reflective parts is used, then illumination can be achieved, but lighting elements in the beam path would impair the imaging

Engineering Contradiction:
ImproveilluminationVSAvoidimaging quality
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The illumination and imaging functions are segmented into separate optical paths. The light guide plate with its exit pupils is positioned such that the illumination light emerges at locations that do not interfere with the imaging beam path. This spatial segmentation allows both functions to operate simultaneously without mutual interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The illumination light is directed into the object plane from a different spatial dimension or angle compared to the imaging beam path. By utilizing the lateral exit pupils of the light guide plate, the illumination light can be coupled into the object plane without interfering with the axial imaging path, effectively using another dimension for illumination delivery.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Illumination intensity

If decoupling through holograms is used, then illumination can be provided, but strong dispersion behavior occurs which is unsuitable for broadband light

Engineering Contradiction:
ImproveilluminationVSAvoidspectral compatibility
Core Design Contradiction:
Illumination intensityVSAdaptability or versatility

Solution Approach 1:

The holographic decoupling mechanism is replaced with a geometric optical approach using a light guide plate with exit pupils. Instead of using diffractive holograms that cause dispersion, the invention uses refractive and reflective geometries in the light guide plate to direct light. This substitution maintains broadband spectral compatibility while achieving effective illumination decoupling.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Illumination intensity

If conventional microscope incident light illumination with beam splitters is used, then illumination can be achieved, but the thickness of the beam splitter scales with the area to be illuminated, preventing axial miniaturization

Engineering Contradiction:
ImproveilluminationVSAvoidaxial length
Core Design Contradiction:
Illumination intensityVSLength of moving object

Solution Approach 1:

The beam splitter function is segmented and replaced by a light guide plate with distributed exit pupils. Instead of using a single thick beam splitter that scales with illumination area, the invention uses a laterally extended light guide plate with multiple exit pupils that can be optically coupled to the imaging system. This segmentation allows miniaturization while maintaining illumination capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The thick beam splitter is replaced by a thin light guide plate that can be laterally extended without increasing axial thickness. The light guide plate acts as a thin-film optical element that delivers illumination through its exit pupils, enabling miniaturization while maintaining the ability to illuminate large object areas.

Inventive Principle:
Principle #30Flexible shells and thin films

5Length of moving object

If miniaturized multi-aperture imaging system with short working distance is used, then compactness is achieved, but sufficient object field illumination with incident light becomes difficult

Engineering Contradiction:
Improveworking distanceVSAvoidobject field illumination
Core Design Contradiction:
Length of moving objectVSIllumination intensity

Solution Approach 1:

The illumination function is segmented from the imaging optics by using separate light guide elements positioned close to the object plane. The light guide plate with exit pupils can be optically coupled to the miniaturized imaging system while providing illumination to the object field. This segmentation allows both compact imaging geometry and sufficient illumination without requiring large working distances.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The illumination light is delivered to the object plane from a lateral dimension through the exit pupils of the light guide plate, rather than requiring axial illumination from the imaging side. This dimensional approach allows illumination of the object field without increasing the axial working distance, maintaining compactness while providing sufficient light.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 efficient incident light illumination of the object plane with improved image quality and a compact optics arrangement, suitable for miniaturized multi-aperture imaging systems with short working distances.

Implementation Method 1

a waveguide (120) with a plurality of deflection structures (130) which are arranged on a side (122, 124) of the waveguide (120) facing the object plane (111) and/or on a side (122, 124) of the waveguide (120) facing the multi-channel imaging system (110)

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

the deflection structures (130) are designed to deflect the guided light (101) in the direction of the object plane (111), so that the object plane (111) is illuminated

Methodology Applied
Scientific EffectLight deflection: Refraction

Data Source

PatentEP2681605B1Optical arrangement and method for optically scanning an object plane using a multichannel imaging system
Publication Date: 2016.06.22 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP2681605B1 patent drawingFigure 1
  • EP2681605B1 patent drawingFigure 2
  • EP2681605B1 patent drawingFigure 3

AI summary

An optical arrangement comprises a multichannel imaging system for optically scanning an object plane in fields of view, which adjoin one another or overlap in the object plane, of a plurality of optical channels of the multichannel imaging system and a waveguide, which is arranged between the object plane and the multichannel imaging system in order to guide light laterally in the waveguide, wherein the waveguide has a multiplicity of deflection structures, which are arranged on a side facing the object plane and/or on a side facing the multichannel imaging system, which sides are part of the waveguide, wherein the deflection structures are arranged in dead zones between the fields of view of the optical channels, and wherein the deflection structures are configured to deflect the guided light in the direction of the object plane such that the object plane is illuminated.