Scintillator Columnar Crystals Light Collimation

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Solution Overview

Problem

X-ray detection systems using digital radiography face data errors due to light diffusion or spreading from scintillators, which affects the accuracy of X-ray image capture.

Innovation Solution

A scintillator with a substrate and a scintillator layer comprising columnar crystals with an aspect ratio of 80:1 or greater, featuring a seed portion and a growth portion, where the columnar crystals have a smaller diameter in the seed portion than in the growth portion, is used to improve light collimation, preventing data errors by minimizing light diffusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional scintillator with irregular crystal structure is used, then the scintillator can be easily manufactured, but light diffusion or spreading occurs causing data errors

Engineering Contradiction:

Improvedata accuracyVSAvoidcrystal structure control

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the physical parameters of crystal growth by controlling super-cooling degree during different stages. By adjusting temperature parameters (higher super-cooling for seed portion, lower super-cooling for growth portion), the patent achieves controlled columnar crystal formation with high aspect ratios, resolving the contradiction between manufacturing ease and light collimation performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies different growth conditions to different portions of the scintillator. The seed portion is grown under higher super-cooling degree to initiate columnar structure, while the growth portion is grown under lower super-cooling degree to extend columns vertically. This local differentiation creates the desired high aspect ratio columnar crystals that prevent light diffusion

Inventive Principle:

Principle #3Local quality

2Measurement precision

If the scintillator layer is made thicker to improve X-ray detection, then detection sensitivity increases, but light diffusion spreads to neighboring pixels

Engineering Contradiction:

ImproveX-ray detection sensitivityVSAvoidlight signal integrity

Core Design Contradiction:

Measurement precisionVSLoss of information

Solution Approach 1:

The patent transitions from considering only the vertical thickness dimension to incorporating crystal orientation and aspect ratio. By creating columnar crystals with high aspect ratios (vertical dimension much greater than horizontal dimension), the patent enables thicker scintillator layers that maintain light collimation. The columnar structure guides light vertically while preventing lateral diffusion, thus resolving the contradiction between thickness and signal integrity

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If columnar crystals with high aspect ratio are formed, then light collimation is improved, but manufacturing process complexity increases

Engineering Contradiction:

Improvelight collimationVSAvoidcrystal growth process

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the crystal growth process into two distinct stages: seed portion formation and growth portion formation. Each stage uses different super-cooling degrees optimized for its specific purpose. This segmentation allows the complex high aspect ratio crystal structure to be achieved through a systematic, controllable two-step process rather than a single complex step

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses parameter changes (super-cooling degree adjustment) as the primary control mechanism for crystal morphology. By changing only the temperature parameter between stages while keeping other conditions relatively constant, the patent achieves complex columnar crystal structures through a simple parameter adjustment, maintaining ease of manufacture

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

The solution effectively reduces data errors by ensuring that visible light is transmitted directly to the intended light sensing pixels without spreading, enhancing the accuracy of X-ray image detection and resolution.

Implementation Method 1

indirectly measures the amount of detected X-rays by converting irradiated X-rays into visible light

Methodology Applied

Scientific EffectScintillation: Scintillation

Implementation Method 2

each of the columnar crystals has an aspect ratio of 80:1 or greater... improving light collimation... preventing data errors due to light diffusion or spreading

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS9146324B2Scintillator, method of fabricating the same and X-ray detector including the scintillator

Publication Date: 2015.09.29 SAMSUNG DISPLAY CO LTD

AI summary

A scintillator, which can prevent a data error due to light diffusion or spreading by improving light collimation, a method of fabricating the same and an X-ray detector including the scintillator are disclosed. The scintillator includes a substrate and a scintillator layer formed on the substrate and having columnar crystals and non-columnar crystals, wherein each of the columnar crystals has an aspect ratio of 80:1 or greater.