Scintillator Coating for Image Sensor Resolution
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Solution Overview
Problem
Existing radiological image sensors face inefficiencies in directly detecting X-rays due to the loss of resolving power caused by the emission of visible light through scintillators, leading to suboptimal spatial resolution and potential electron saturation in detectors.
Innovation Solution
An image sensor design featuring a scintillator with a luminescent material layer having asperities covered by a coating material that partially absorbs detection radiation, applied using a low-surface-energy solvent and dry vapor evaporation method, enhancing spatial resolution and light efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the thickness of the luminescent material layer is increased to improve light efficiency, then the light efficiency is improved, but the spatial resolution deteriorates
Solution Approach 1:
The luminescent material layer is segmented into needle-like structures (asperities) rather than a continuous layer. This segmentation allows light to be channeled through discrete pathways, improving spatial resolution while maintaining effective light conversion thickness.
Solution Approach 2:
The scintillator structure transitions from uniform luminescent material to localized needle structures with specific geometric properties. The needles have optimized dimensions (3-6 micrometers) that provide both sufficient light conversion and spatial confinement for high resolution imaging.
2Measurement precision
If the luminescent material emits high levels of visible radiation to improve detection sensitivity, then the detection sensitivity is improved, but electron saturation occurs in the detector
Solution Approach 1:
The coating material is applied locally to the needle structures rather than uniformly across the entire scintillator. This localized application allows precise control of light emission levels at the needle level, matching detector capacity while maintaining overall detection sensitivity.
Solution Approach 2:
The optical properties of the scintillator system are modified by introducing a coating material with specific absorption characteristics. This changes the effective light emission parameter to match detector capacity, preventing electron saturation while maintaining adequate signal levels.
3Object-generated harmful factors
If a filter is applied to reduce visible radiation levels to match detector capacity, then electron saturation is prevented, but the application process becomes complex and costly
Solution Approach 1:
Instead of adding a separate filter layer, the invention modifies the existing needle structures by coating them directly. This changes the optical parameters of the scintillator itself, achieving radiation level control through a simpler single-step process rather than multi-layer filtering.
Solution Approach 2:
The filtering function is extracted from a separate filter component and integrated directly into the needle structures through coating. This eliminates the need for additional filter layers and simplifies the overall device structure and application process.
4Object-generated harmful factors
If a filter is used to attenuate visible radiation energy, then light efficiency is reduced to match detector capacity, but spatial resolution is not improved and application costs increase
Solution Approach 1:
The scintillator is segmented into needle structures that inherently provide spatial resolution through their geometric configuration. The coating material applied to these needles simultaneously achieves both spatial resolution enhancement and radiation attenuation, eliminating the need for separate filtering components.
Solution Approach 2:
The functions of spatial resolution enhancement and radiation attenuation are merged into a single integrated structure - the coated needle scintillator. This combines the benefits of both features while reducing overall device complexity and application costs.
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 significantly improves spatial resolution by up to 30% at specific spatial frequencies and ensures uniform attenuation of light efficiency, simplifying the application process and reducing costs and equipment risks.
Implementation Method 1
the surface of which has asperities, separated by interstices, a detection radiation emerging from the second side of the layer of luminescent material when the luminescent material is illuminated by a probe radiation through the substrate, characterized in that the second side of the layer of luminescent material is covered with a film of a coating material partially absorbing the detection radiation
Implementation Method 2
the invention is of particular use in the field of radiological imaging where the image sensors include a scintillator for converting a probe radiation, for example an X- or Gamma-range radiation, into a normally visible detection radiation
Implementation Method 3
Thallium-doped caesium iodide Csl, in needle form, offers an interesting alternative for a greater light efficiency associated with a waveguide effect of the needles
Implementation Method 4
the operation comprising a first step of slow immersion of the layer of luminescent material in a coating solution including a solvent that is inert relative to the material of the substrate, to the luminescent material and the coating material, the coating solution having a low surface energy
Implementation Method 5
followed by a second step of evaporation of the solvent in dry vapour phase
Data Source
AI summary
An image sensor includes a scintillator comprising a substrate covered with a layer of luminescent material, the layer of luminescent material comprising a first side in contact with the substrate and a second side, the surface of which has asperities, separated by interstices, a detection radiation emerging from the second side of the layer of luminescent material when the luminescent material is illuminated by a probe radiation through the substrate, characterized in that the second side of the layer of luminescent material is covered with a film of a coating material partially absorbing the detection radiation, and moulding itself to the asperities of the surface of the second side of the layer of luminescent material.