Back-Illuminated X-ray Sensor Shielding Layer Noise Suppression
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Solution Overview
Problem
X-ray CCDs detect noise light such as ultraviolet, visible, and infrared light, leading to deterioration in S/N performance, and existing solutions like Optical Blocking Filters increase device size and structural complexity, especially in space-based applications.
Innovation Solution
A back-illuminated solid-state image pickup element with a shielding layer comprising a first aluminum layer, an ultraviolet light shielding layer, and a second aluminum layer directly on the X-ray incident surface, integrated to block noise light wavelengths, reducing device size and structural complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an OBF (Optical Blocking Filter) is attached to block noise light, then noise light detection is suppressed, but the device size increases and structural complexity increases
Solution Approach 1:
The patent integrates the optical blocking function directly into the image pickup element by forming a shielding layer on the light-receiving surface. This merges the noise light blocking function with the X-ray detection function, eliminating the need for a separate OBF component and its associated mounting structure, thereby reducing device complexity while maintaining noise light suppression capability
Solution Approach 2:
The image pickup element is designed to perform multiple functions: X-ray detection through the back-illuminated structure and noise light blocking through the integrated shielding layer. This multi-functional design eliminates the need for separate dedicated noise light blocking components, reducing overall device complexity
2Object-affected harmful factors
If an OBF is attached to block noise light, then noise light detection is suppressed, but the device size increases
Solution Approach 1:
The shielding layer is formed as an integral part of the image pickup element structure, merging the noise light blocking function within the existing device footprint. This eliminates the need for additional space required by separate OBF components and their mounting structures, thereby preventing device size increase
3Use of energy by moving object
If the OBF film thickness is made thin for transmitting X-rays, then X-ray transmission is improved, but the device structure becomes weak
Solution Approach 1:
The shielding layer is formed directly on the light-receiving surface of the image pickup element, merging the noise light blocking function with the existing structural component. This integration provides structural support while maintaining thin film thickness for X-ray transmission, as the shielding layer serves dual purposes of optical blocking and structural reinforcement
4Object-affected harmful factors
If a shielding layer is provided on the X-ray incident surface, then noise light detection is suppressed, but the device structure becomes complicated
Solution Approach 1:
The shielding layer is formed as an integral part of the image pickup element structure through direct formation on the light-receiving surface. This merging of functions eliminates the need for separate mounting structures, brackets, or additional components that would be required if the shielding layer were a separate attachable component, thereby reducing device structural complexity
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 configuration effectively suppresses noise light detection, ensuring improved S/N performance and structural integrity, particularly in space-based X-ray imaging devices.
Implementation Method 1
a shielding layer provided on the X-ray incident surface of the solid-state image pickup element and used for blocking light rays with wavelengths longer than the wavelength of X-rays as a detection target
Implementation Method 2
the shielding layer includes a first aluminum layer provided directly on the X-ray incident surface, a second aluminum layer provided on the first aluminum layer, an ultraviolet light shielding layer provided between the first aluminum layer and the second aluminum layer and used for blocking ultraviolet light rays
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3(a)~3(b)
AI summary
An X-ray imaging device 1 includes a back-illuminated solid-state image pickup element 10 including an X-ray detection section having a plurality of detection pixels arrayed for detecting incident X-rays formed on one surface 11 side, and an X-ray incident surface on the other surface 12, and a shielding layer 20 provided on the incident surface 12 of the image pickup element 10 and to be used for blocking light rays with wavelengths longer than the wavelength of X-rays as a detection target. The shielding layer 20 includes a first aluminum layer 21 provided directly on the incident surface 12, a second aluminum layer 22 provided on the first aluminum layer 21, and an ultraviolet light shielding layer 25 that is provided between the first and second aluminum layers 21 and 22 and is used for blocking ultraviolet light rays. Accordingly, an X-ray imaging device capable of suppressing the influence of detection of noise light in X-ray detection is realized.