X-ray Detector Light Emission Layer OLED Uniformity

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Solution Overview

Problem

X-ray detectors suffer from phantom images and non-uniform spatial gain, which affect their resolution and ease of production.

Innovation Solution

Incorporating a light emission layer with OLEDs between the scintillator and reflector layers, with a distance of less than 50 µm, to enhance responsivity and prevent phantom images, using a combination of CMOS or CCD light detection and metal shunt lines for improved emission uniformity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional X-ray detector structure is used, then the device is simple to manufacture, but the spatial gain uniformity is poor and phantom images occur

Engineering Contradiction:
Improvespatial gain uniformityVSAvoiddetector structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The detector is divided into distinct functional layers: scintillator layer, light emission layer (with OLEDs), and reflector layer. This segmentation allows each layer to be optimized independently for its specific function, improving spatial gain uniformity while maintaining manufacturability through modular assembly

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The light emission layer with OLEDs is positioned between the scintillator and reflector layers to preemptively emit light that fills in dark spots before the reflector reflects light. This preliminary action prevents phantom images by ensuring uniform illumination across the detection surface

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If the distance between scintillator layer and reflector layer is reduced, then the resolution and responsivity improve, but the space for light emission layer is limited

Engineering Contradiction:
ImproveresolutionVSAvoidlight emission layer space
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The OLEDs in the light emission layer are implemented as thin flexible light-emitting elements that can function effectively in the constrained space between the scintillator and reflector layers. This thin-film approach maintains the required small distance (less than 50 µm) for high resolution while still providing sufficient volume for light emission functionality

Inventive Principle:
Principle #30Flexible shells and thin films

3Manufacturing precision

If secondary radiation source is added to prevent phantom images, then the spatial uniformity improves, but the device complexity and cost increase

Engineering Contradiction:
Improvespatial uniformityVSAvoidproduction complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The light emission layer with OLEDs is merged into the existing detector structure between the scintillator and reflector layers. This integration combines the secondary radiation source function with the existing light detection pathway, improving spatial uniformity without requiring separate additional components or complex assembly procedures

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The light emission layer serves multiple functions: it acts as a secondary radiation source to prevent phantom images, enhances spatial gain uniformity, and works synergistically with the reflector layer to improve overall detector responsivity. This multi-functionality reduces the need for separate components

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 increases the detector's responsivity and resolution while reducing phantom images, making the X-ray detector easier and cheaper to produce with improved modulation transfer function performance.

Implementation Method 1

a scintillator layer which converts incident X-rays into light

Methodology Applied
Scientific EffectScintillation: Scintillation

Implementation Method 2

a reflector layer for reflecting light generated within the scintillator layer towards the light detection arrangement

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

The light emission layer comprises an OLED (organic light emitting diode)

Methodology Applied
Scientific EffectOrganic Light-emitting Diode: Organic Light-emitting Diode

Data Source

PatentEP2564240B1X-ray detector with improved spatial gain uniformity and resolution and method of fabricating such x-ray detector
Publication Date: 2019.06.12 KONINKLIJKE PHILIPS NV
  • EP2564240B1 patent drawingFigure 1~4
  • EP2564240B1 patent drawingFigure 5~6

AI summary

An X-raydetector (1) is proposed comprising a light detection arrangement (3) such as a CMOS photodetector, a scintillator layer (5) such as a CsI:Tl layer, a reflector layer (9) and a light emission layer (7) interposed betweenthe scintillator layer (5) and the reflector layer (9). The light emission layer (7) may comprise an OLED and may be made with a thickness of less than 50 µm. Thereby, a sensitivity and resolutionofthe X-raydetector may be improved.