Diffractive Optical Element for Structured Line Focus

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Solution Overview

Problem

Existing methods for generating a line focus for material processing, such as those used in OLED display production, suffer from high power loss and inefficiency due to the use of masks and projection lenses, as well as issues like speckle formation and sensitivity to adjustment errors in diffuser and beam shaper principles.

Innovation Solution

The implementation of beam shaping optics with a beam splitter function that generates the desired structuring directly, eliminating the need for projection optics and maximizing light yield in the processing plane, using diffractive optical elements to create an intensity-structured line focus with high homogeneity and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a mask and projection lens are used to generate structured line focus, then the desired intensity distribution can be achieved, but high power loss occurs in the mask plane and the overall length increases

Engineering Contradiction:
Improveintensity distributionVSAvoidpower loss
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The patent combines the mask function and projection lens function into a single diffractive optical element (DOE). The DOE directly generates the structured line focus pattern without requiring separate masking and projection components, thereby eliminating power loss in the mask plane and reducing the overall optical path length while maintaining the desired intensity distribution

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The diffractive optical element performs multiple functions simultaneously: it acts as both the mask that defines the intensity distribution and the projection lens that focuses the light into a line focus. This multi-functional design eliminates the need for separate components and reduces energy loss

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

2Ease of operation

If a diffuser is used to generate line focus, then the far-field distribution is formed through diffraction, but speckle occurs leading to strong intensity fluctuations

Engineering Contradiction:
Improveinsensitivity to adjustment errorsVSAvoidintensity homogeneity
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent changes the fundamental parameter of how the diffuser/DOE generates the line focus. Instead of relying on far-field diffraction from each sub-area (which causes speckle), the DOE is designed to directly form the structured line focus in the near field through carefully engineered diffraction patterns, eliminating speckle while maintaining adjustment insensitivity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The diffractive optical element is pre-designed with specific phase and amplitude modulations that directly encode the desired line focus intensity distribution. This preliminary encoding of the target pattern into the DOE structure eliminates the need for far-field diffraction and prevents speckle formation from the outset

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If a beam shaper with DOE is used, then good line homogeneity is achieved without speckle, but sensitive adjustment and susceptibility to light source fluctuations occur

Engineering Contradiction:
Improveline homogeneityVSAvoidadjustment sensitivity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The diffractive optical element is pre-configured with the exact phase and amplitude distributions needed to generate the structured line focus directly. This preliminary encoding of the optimal beam shape into the DOE structure eliminates the need for sensitive post-alignment adjustments and makes the system robust against light source fluctuations

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If mask and projection optics are used, then structured line focus is generated, but the arrangement becomes inefficient due to light loss in the mask plane

Engineering Contradiction:
Improvetarget structuringVSAvoidlight yield
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent merges the mask and projection optics into a single diffractive optical element that directly generates the structured line focus. This integration eliminates the mask plane where light is lost, thereby maximizing light yield and improving productivity while maintaining the desired target structuring

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and eliminates the inefficient mask component from the optical system. By removing the separate mask and its associated projection optics, the system eliminates the source of light loss in the mask plane while retaining the essential function of generating structured line focus through the integrated DOE

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 approach allows for high-resolution, efficient material processing with reduced light loss and improved homogeneity, enabling the production of small but high-resolution displays like those for mobile devices, and reduces the need for high-powered lasers by optimizing light distribution.

Implementation Method 1

The diffractive element (DOE), designed as a diffractive optical element (DOE), forms the desired intensity distribution in the far field, for example a line focus, through diffraction on diffractive structures

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP2622400B1Arrangement and method for generating a light beam for material processing
Publication Date: 2018.08.29 JENOPTIK OPTICAL SYSTEMS GMBH
  • EP2622400B1 patent drawingFigure 1~3
  • EP2622400B1 patent drawingFigure 4~5
  • EP2622400B1 patent drawingFigure 6

AI summary

The invention relates to an arrangement for generating a light beam for material processing, having a light source (1) emitting a light beam (11), a beam shaping lens (14) disposed downstream of the light source (1) and imaging the light beam (11) in a processing plane (7) at a predetermined target structure, wherein the beam shaping optic (14) comprises a beam dividing function for generating the target structure.