CT Detector Light Guide Cross-Sectional Area Transition
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Solution Overview
Problem
Existing CT imaging systems face challenges in detector assembly design, particularly due to the high cost of custom silicon diodes required to match the dimensions of tightly packed pixels, and inefficiencies in light collection and guidance systems.
Innovation Solution
A detector assembly is designed with a scintillator block and photodiodes, where a light guide with varying cross-sectional areas is used to couple the scintillator pixels to photodiodes, allowing for a larger pixel footprint without the need for custom diodes, and featuring a light guide with light pipes that efficiently direct x-ray converted light to photodiodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If custom silicon diodes are manufactured to match the dimensions of tightly packed pixels, then detection precision is improved, but manufacturing cost increases
Solution Approach 1:
A light guide is introduced as an intermediary component between the scintillator pixels and the photodiodes. The light guide has a first end with a larger cross-sectional area that couples to the scintillator pixels, and a second end with a smaller cross-sectional area that couples to the photodiodes. This intermediary structure allows standard photodiodes to be used while maintaining effective light coupling, thereby reducing manufacturing costs without sacrificing detection precision.
2Loss of energy
If the pixel array area matches the diode array area, then light collection efficiency is improved, but device complexity increases
Solution Approach 1:
The cross-sectional area parameter of the light guide is varied along its length. The first end has a larger cross-sectional area that matches the scintillator pixel array, while the second end has a smaller cross-sectional area that matches the photodiode array. This gradual parameter change allows efficient light collection from the larger scintillator area while using standard-sized photodiodes, simplifying the overall device structure.
3Ease of manufacture
If a light guide with varying cross-sectional areas is used to couple scintillator pixels to photodiodes, then manufacturing cost is reduced, but light guidance efficiency may worsen
Solution Approach 1:
The light guide utilizes the third dimension (length along the optical path) to gradually transition the cross-sectional area from the larger scintillator interface to the smaller photodiode interface. This dimensional approach allows efficient light guidance through controlled total internal reflection, maintaining high light guidance efficiency while enabling the use of standard photodiodes and reducing manufacturing 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
This configuration reduces manufacturing costs by eliminating the need for custom diodes and enhances light collection and guidance, improving the overall efficiency of the detector assembly in CT imaging systems.
Implementation Method 1
a scintillator block (402) including a plurality of pixels (404), wherein each pixel (404) is configured to receive x-ray beams (406)
Implementation Method 2
a plurality of photodiodes (420)... Each detector element of the array produces a separate electrical signal that is a measurement of the beam intensity at each detector location
Implementation Method 3
a light guide (422)... wherein the first cross-sectional area is larger than the second cross-sectional area... efficiently direct x-ray converted light to photodiodes
Data Source
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AI summary
A detector assembly (400) for a CT imaging system is provided. The detector assembly including a scintillator block (402) including a plurality of pixels (404), each pixel configured to receive x-ray beams (406) travelling in a transmission direction (410), a plurality of photodiodes (420), and a light guide (422) coupled between the scintillator block (402) and the plurality of photodiodes (420), the light guide (422) including a plurality of light pipes (424), each light pipe (424) configured to guide light emitted from a pixel of the plurality of pixels (404) into an associated photodiode (420) of the plurality of photodiodes, wherein each pixel (404) has a first cross-sectional area (430) that is substantially perpendicular to the transmission direction (410), wherein each photodiode (420) has a second cross-sectional area (432) that is substantially perpendicular to the transmission direction (410), and wherein the first cross-sectional area (430) is different from the second cross-sectional area (432).