Optical Measuring Arrangement for X-ray Grid Alignment

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Solution Overview

Problem

Current methods are limited in determining the precise relative arrangement, including angle and position, of multiple X-ray grids, which is crucial for Talbot-Lau interferometry, as they can only measure tilting in two rotational degrees of freedom and require physical prisms for alignment.

Innovation Solution

An optical measuring arrangement with a point light source, detector, lens, and mirrors aligned along a common optical axis, utilizing beam splitters to generate independent measurement beam paths that can be directed onto multiple X-ray grids, allowing for precise determination of their relative position and angle, even when grids are far apart.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a single measuring beam path is used with a prism, then the measurement setup is simple, but only tilts in two rotational degrees of freedom can be measured and only a single object can be measured

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidsetup complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The single measuring beam path is segmented into multiple independent measuring beam paths using beam splitters. Each beam path can independently measure a different X-ray grating, enabling the system to measure multiple objects simultaneously while maintaining a relatively simple overall setup architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The measuring arrangement is designed to be universal by enabling measurement of multiple X-ray gratings with different orientations and positions through the use of beam splitters. The system can measure tilts in two rotational degrees of freedom for each grating, making it adaptable to various measurement configurations without requiring separate measurement setups.

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

2Area of stationary object

If X-ray gratings are arranged as tiles to achieve large surface area, then the measurement coverage is improved, but the alignment precision between tiles becomes more difficult to maintain

Engineering Contradiction:
Improvemeasurement surface areaVSAvoidalignment precision
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The mechanical alignment process is replaced by an optical measurement system using laser beams and beam splitters. This non-contact optical method provides precise measurement of the relative arrangement of multiple X-ray gratings, achieving alignment precision of 10 micrometers without requiring physical contact or complex mechanical adjustment mechanisms.

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

Solution Approach 2:

The measuring arrangement creates optical copies (light beams) of the X-ray gratings by reflecting laser light off each grating surface. These optical copies are detected and analyzed to determine the precise relative positions and orientations of the gratings, enabling accurate alignment assessment without physically moving or disturbing the gratings.

Inventive Principle:
Principle #26Copying

3Adaptability or versatility

If multiple independent measuring arrangements are used to measure multiple X-ray gratings, then the measurement versatility is improved, but the device complexity and cost increase significantly

Engineering Contradiction:
Improvemeasurement versatilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple measuring beam paths are merged into a single integrated measuring arrangement through the use of beam splitters. The beam splitters combine the optical paths of multiple laser beams, allowing them to share common components such as the detector and optical axis. This merging approach enables measurement of multiple X-ray gratings simultaneously while avoiding the need for separate independent measuring arrangements, thus reducing overall system complexity and cost.

Inventive Principle:
Principle #5Merging (Combining)

4Measurement precision

If prisms are placed on X-ray gratings for measurement, then the alignment measurement is enabled, but the measurement process becomes more complex and time-consuming

Engineering Contradiction:
Improvealignment measurement capabilityVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The physical prism component is extracted and removed from the measurement process. Instead of placing prisms on the X-ray gratings, the invention uses the gratings themselves as the reflective surfaces for the laser beams. The beam splitters and optical system are configured to directly measure the grating surfaces without requiring any additional alignment accessories, thereby eliminating the time-consuming process of prism placement and removal.

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

Enables accurate and efficient measurement of the relative position and angle of multiple X-ray grids in various configurations, including those that are adjacent or spaced apart, overcoming the limitations of existing methods by allowing for precise alignment and interference pattern analysis.

Implementation Method 1

A point light source 3, in particular a collimated laser point light source 3, is provided, which creates a light beam path L. Furthermore, a lens 4 as well as a mirror 5 are provided, which are arranged along the main optical axis AA. Moreover, a beam splitter 7 is provided, which is arranged in such a way that the light beam path L is divided at the beam splitter 7, whereby a first measuring beam path M1 is generated, which strikes a first X-ray grating 2, and a second measuring beam path M2 is generated, which strikes a second X-ray grating 2.

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The reflected light beams from multiple X-ray gratings are superimposed and focused onto a detector, creating interference patterns that encode the relative position and orientation information of the gratings. This enables precise measurement of the grating arrangement through optical interference and diffraction effects.

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP3295122B1Optical measuring arrangement and method for determining the angle and position of measurement objects
Publication Date: 2019.07.24 KARLSRUHER INST FUR TECH
  • EP3295122B1 patent drawingFigure 1~2
  • EP3295122B1 patent drawingFigure 3~4
  • EP3295122B1 patent drawingFigure 5

AI summary

The present invention provides an optical measuring arrangement (1) for determining the angle and position of measurement objects and a method for evaluating a relative arrangement of at least two measurement objects in relation to one another. The optical measuring arrangement (1) has a point light source (3) for generating a light beam path, a detector (6), a lens (4) for focusing the beam path on the detector (6), and at least one mirror (5) for deflecting the beam path onto the measurement object. The lens (4), the detector (6), and the mirror (5) thereby lie on a common optical axis (A-A). According to the invention, at least one beam splitter (7) is arranged along the optical axis (A-A) between the lens (4) and mirror (5), for generating at least two measurement beam paths that are independent from one another, for illuminating at least two measurement objects.