Lithographic Collimator Element Manufacturing
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Solution Overview
Problem
Current manufacturing methods for scattered-radiation collimators in X-ray computed tomography devices are limited by minimum wall thickness and tungsten proportion, leading to suboptimal X-ray absorption and increased production costs, which are exacerbated by the need for precise alignment and smaller pixel sizes in ultra-high resolution CT applications.
Innovation Solution
A method involving lithographic coating and cathode sputtering to create thinner X-ray absorbing layers, allowing for the production of collimator elements with reduced wall thickness and improved alignment tolerances, enabling more efficient scattered-radiation collimation while maintaining high detective quantum efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional manufacturing methods (metal plates, selective laser melting) are used for collimator elements, then sufficient X-ray absorption is achieved, but minimum wall thickness constraints and high production costs occur
Solution Approach 1:
The patent changes the manufacturing parameters by using a lithographic coating layer with thickness of at least 0.5 mm (unconventional thickness) and applying cathode sputtering to deposit X-ray absorbing material. This combination allows achieving sufficient X-ray absorption with thinner walls compared to conventional methods, while the lithographic process enables cost-effective mass production
Solution Approach 2:
The patent creates a composite structure by combining a lithographic coating layer (polymer-based, at least 0.5 mm thick) with an X-ray absorbing layer (metallic material applied via cathode sputtering). This composite approach leverages the mechanical stability of the thick polymer layer and the high X-ray absorption coefficient of the metallic coating, achieving both thin wall thickness and effective radiation attenuation
2Manufacturing precision
If collimator wall thickness is reduced to improve alignment tolerances and detective quantum efficiency, then scattered radiation suppression capability deteriorates
Solution Approach 1:
The patent applies cathode sputtering to deposit a high-density X-ray absorbing material layer on the lithographic coating. This process enables achieving high attenuation capability in a thin layer, allowing wall thickness reduction while maintaining scattered radiation suppression. The sputtered layer's high atomic number material provides superior absorption per unit thickness
Solution Approach 2:
The composite structure of thick lithographic coating (≥0.5 mm) plus thin sputtered X-ray absorbing layer creates an optimized wall design. The lithographic layer provides mechanical integrity and alignment tolerance, while the thin metallic layer delivers high X-ray absorption, together suppressing scattered radiation effectively despite reduced overall wall thickness
3Stability of the object's composition
If lithographic coating layer thickness is increased to at least 0.5 mm for better structural stability, then manufacturing complexity and process time increase
Solution Approach 1:
The patent applies a relatively thick lithographic coating layer (at least 0.5 mm) as a preliminary structural foundation before applying the X-ray absorbing material. This pre-established thick polymer layer provides immediate structural stability and alignment tolerance, simplifying subsequent manufacturing steps and reducing the need for additional reinforcement structures
4Quantity of substance
If conventional collimator elements are used with metal plates, then X-ray absorption is achieved, but geometric DQE (detector surface area) is reduced due to thicker walls
Solution Approach 1:
The patent uses cathode sputtering to deposit a thin layer of high-density X-ray absorbing material, achieving superior absorption capacity per unit thickness compared to conventional metal plates. This allows reducing wall thickness while maintaining or improving X-ray absorption, thereby increasing the effective detector surface area
Solution Approach 2:
The composite structure combines the mechanical properties of thick lithographic coating with the high absorption properties of thin sputtered metallic layer. This optimization reduces overall wall thickness compared to solid metal plates, increasing the geometric DQE and effective detector surface area while maintaining adequate X-ray absorption capacity
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 method enables the production of collimator elements with reduced wall thickness and improved alignment, enhancing X-ray absorption and reducing production costs, thus addressing the limitations of existing technologies and meeting the demands of ultra-high resolution CT applications.
Implementation Method 1
the lithographic coating layer is exposed in exposure regions that correspond to a structure of the collimator element
Implementation Method 2
an X-ray absorbing layer is applied via cathode sputtering
Implementation Method 3
an X-ray absorbing layer is applied via cathode sputtering; the absorption of radiation in a material is exponential in relation to its thickness
Data Source
AI summary
A method is disclosed for manufacturing a collimator element. The method includes applying a lithographic coating layer. The lithographic coating layer is then exposed using a grid mask. Exposure regions then correspond to a structure of the collimator element. Here, the structure of the collimator element is aligned on a common focus. The lithographic coating layer is then developed to give a pre-structure of the collimator element. Further, an X-ray absorbing layer is applied via cathode sputtering. At least the X-ray absorbing layer is then removed from regions of the pre-structure. A collimator element, a method for manufacturing a scattered-radiation collimator, a scattered-radiation collimator, a radiation detector and a CT device are also disclosed.