X-ray Imaging Apparatus Phase Contrast Resolution

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Solution Overview

Problem

Conventional X-ray image photographing methods face challenges in freely adjusting phase contrast and absorption contrast while maintaining high magnification ratios, especially when photographing fine structures with high resolution, and struggle with imaging thick specimens using electron beams.

Innovation Solution

The method involves adjusting the distance between the specimen and detector relative to the X-ray source to achieve a ratio of d/L < 1, using a high-powered X-ray source with a finite size, and a detector with a space resolution of 2 µm or less, allowing for high-resolution phase contrast and absorption contrast imaging within a short time, and employing a virtual X-ray source for improved resolution and quantitative CT reconstruction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnified projection is used to photograph fine structures with high resolution, then spatial resolution is improved, but the ability to freely adjust phase contrast and absorption contrast while maintaining magnification ratio deteriorates

Engineering Contradiction:
Improvespatial resolutionVSAvoidadjustability of phase contrast and absorption contrast
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The invention makes the distance d between specimen and detector dynamically adjustable while maintaining a small d/L ratio. This dynamic adjustment capability allows the system to switch between different contrast modes (phase contrast and absorption contrast) without changing the magnification ratio, thereby resolving the contradiction between high spatial resolution and adaptability of contrast adjustment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the parameter d (distance from specimen to detector) while keeping d/L sufficiently small. By adjusting d within a range that maintains the small ratio condition, the system can optimize for either phase contrast or absorption contrast while preserving high magnification ratio and spatial resolution, thus resolving the technical contradiction.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If electron beam is used to photograph thick specimens, then high resolution of specimen surface or thin specimen is achieved, but the ability to photograph structure inside thick specimen deteriorates

Engineering Contradiction:
Improveresolution of specimen surfaceVSAvoidcapability to image thick specimen structure
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The invention replaces the electron beam system with an X-ray transmission system. X-rays have penetrating power that allows them to pass through thick specimens, enabling imaging of internal structures. This substitution resolves the contradiction by providing both high resolution capability and the ability to image thick specimens.

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

Solution Approach 2:

The invention changes from electron beam to X-ray radiation, fundamentally altering the physical parameter of the imaging radiation. This parameter change enables penetration through thick specimens while maintaining high resolution through appropriate selection of small d/L ratio and high-power X-ray source.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If high magnification ratio is used to photograph fine structures, then spatial resolution is improved, but photographing time increases

Engineering Contradiction:
Improvespatial resolutionVSAvoidphotographing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The invention uses a high-power X-ray source that provides continuous and intense X-ray radiation. This allows sufficient X-ray flux to reach the detector even with the small solid angle subtended by the small d/L geometry, enabling high-resolution imaging in short time without requiring long exposure times.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The invention increases the power parameter of the X-ray source to compensate for the reduced X-ray flux caused by the small d/L ratio. This parameter change allows high magnification ratio imaging to be performed quickly, resolving the contradiction between spatial resolution and photographing time.

Inventive Principle:
Principle #35Parameter changes

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 enables high-resolution, short-time imaging of fine structures with emphasized phase contrast and absorption contrast, reducing artifacts and allowing for quantitative density information in CT reconstruction, effectively capturing detailed images of specimens with micron-order resolution.

Implementation Method 1

a method for performing photographing using a phase contrast and photographing using an absorption contrast

Methodology Applied
Scientific EffectPhase contrast:

Implementation Method 2

photographing using an absorption contrast with a same apparatus

Methodology Applied
Scientific EffectAbsorption contrast: Absorption (EM radiation)

Implementation Method 3

X-ray transmission image photographing

Methodology Applied
Scientific EffectX-ray transmission: X-Ray

Data Source

PatentEP2439589B1X-ray image photographing method and X-ray image photographing apparatus
Publication Date: 2018.06.20 RIGAKU CORP
  • EP2439589B1 patent drawingFigure 1
  • EP2439589B1 patent drawingFigure 2
  • EP2439589B1 patent drawingFigure 3

AI summary

There is provided an X-ray image photographing method and an X-ray image photographing apparatus capable of photographing a high resolution phase contrast image and a high resolution absorption contrast image in a short time according to the purpose only by finely adjusting the distance between a specimen and a detector with respect to an X-ray source. The X-ray image photographing method enables photographing of a fine structure with a high space resolution while using an X-ray source having a finite size, and d/L is sufficiently smaller than 1, when L is a distance from an X-ray source 110 to a specimen 500 and d is a distance from the specimen 500 to a detector 130. Further, a distance between a peak position and a valley position of a phase contrast is not less than 1/3Δ and not more than 3Δ, when λ is an average wavelength of X-ray to be irradiated from the X-ray source 110 and Δ is a resolution of the detector 130.