Imaging systems
Patent Information
- Authority / Receiving Office
- TW · TW
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2022-02-21
- Publication Date
- 2022-10-01
Smart Images
Figure TWG2TA000877700_001 
Figure TWG2TA000877700_002 
Figure TWG2TA000877700_003
Abstract
Description
[Technical Field]
[0001] This invention relates to an imaging system. [Previous Technology]
[0002] A radiation detector is a device for measuring the properties of radiation. Examples of properties may include the spatial distribution of the intensity, phase, and polarization of the radiation. The radiation may be radiation that has already interacted with an object. For example, the radiation measured by a radiation detector may be radiation that has already penetrated an object. The radiation may be electromagnetic radiation, such as infrared light, visible light, ultraviolet light, X-rays, or gamma rays. The radiation may also be other types, such as alpha rays and beta rays. An imaging system may include an image sensor having multiple radiation detectors. [Summary of the Invention]
[0003] This document discloses an imaging system comprising: an image sensor including: a system printed circuit board (system PCB); M groups of printed circuit boards (groups PCB(i), i=1, ..., M) mounted on a mounting surface of the system PCB; and Ni radiation detectors mounted on the groups PCB(i) for i=1, ..., M, wherein M and Ni are integers greater than 1, i=1, ..., M, wherein the image sensor is configured to scan a scene in a scanning direction, and wherein, for each group PCB(i), there is no plane that (A) is parallel to the normal direction of the mounting surface of the system PCB, (B) is parallel to the scanning direction, (C) divides all effective areas of the Ni radiation detectors into two groups of effective areas, and (D) does not intersect with any effective area of all effective areas of the Ni radiation detectors.
[0004] On one hand, all Ni are the same, where i = 1, ..., M.
[0005] In one aspect, the M group PCBs and the system PCB include semiconductors.
[0006] In one respect, each of the M groups of PCBs has a rectangular shape.
[0007] In one aspect, the M groups of PCBs are arranged as columns extending in the scanning direction.
[0008] In one aspect, all effective regions of all the Ni radiation detectors overlap in the normal direction, where i = 1, ..., M, thereby forming an effective region in the normal direction, where i = 1, ..., M.
[0009] In one aspect, the imaging system further includes a radiation source configured to generate a radiation beam whose boundary does not intersect any of the effective regions of all the Ni radiation detectors when the image sensor scans the scene, where i = 1, ..., M.
[0010] In one aspect, the radiation beam is aimed at each point in the effective region of all the Ni radiation detectors, where i = 1, ..., M.
[0011] In one aspect, the imaging system also includes a mask that allows some of the radiation from the radiation source to pass through the mask to obtain the radiation beam.
[0012] In one respect, for each group of PCB(i), no two effective regions of the Ni radiation detectors overlap in the normal direction, where i=1, ..., M.
[0013] In one aspect, for each group of PCB(i), (A) the Ni radiation detectors of the group of PCB(i) overlap in the normal direction, such that the effective areas of all the Ni radiation detectors form an effective area in the normal direction, and (B) a plane parallel to the normal direction and perpendicular to the scanning direction intersects all the effective areas of the Ni radiation detectors, where i=1, ..., M.
[0014] In one aspect, the M groups of PCBs overlap in the normal direction, such that all the M groups of PCBs form a printed circuit board in the normal direction, and a plane parallel to the normal direction and parallel to the scanning direction intersects with all the M groups of PCBs.
[0015] In one aspect, the imaging system also includes an input / output port on each of the M groups of PCBs.
[0016] In one aspect, the input / output ports on the first group of the M groups of PCBs are sandwiched between the first group of PCBs and the second group of PCBs.
[0017] In one aspect, the input / output ports on the first group of the M groups of PCBs overlap with the effective area on the second group of the M groups of PCBs in the normal direction.
[0018] In one aspect, for each group PCB(i), each of the Ni radiation detectors on the group PCB(i) includes: (A) a radiation absorption layer and (B) an electronic device layer including a plurality of dedicated integrated circuits (ASICs), where i=1, ..., M.
[0019] In one aspect, the radiation absorbing layer and the electronic device layer are electrically connected to each other through vias.
[0020] In one aspect, the radiation absorbing layer includes a plurality of diodes.
[0021] In one aspect, the radiation-absorbing layer comprises a semiconductor.
[0022] In one aspect, the electronic device layer includes an electronic system configured to process signals generated by radiation incident on the radiation-absorbing layer.
Implementation Method
[0024] Radiation detector
[0025] As an example, Figure 1 schematically illustrates a radiation detector 100. The radiation detector 100 may include an array of primitives 150 (also referred to as sensing elements 150). This array may be a rectangular array (as shown in Figure 1), a cellular array, a hexagonal array, or any other suitable array. The primitive 150 array in the example of Figure 1 has 4 columns and 7 rows; however, typically, the primitive 150 array can have any number of rows and any number of columns.
[0026] Each primitive 150 can be configured to detect radiation incident upon it from a radiation source (not shown) and can be configured to measure characteristics of the radiation (e.g., particle energy, wavelength, and frequency). The radiation may include particles, such as photons and subatomic particles. Each primitive 150 can be configured to count the number of radiant particles incident upon it over a period of time, with energy falling into multiple energy ranges. All primitives 150 can be configured to count the number of radiant particles incident upon it within multiple energy ranges over the same period of time. When the incident radiant particles have similar energies, primitive 150 can simply be configured to count the number of radiant particles incident upon it over a period of time without measuring the energy of each individual radiant particle.
[0027] Each primitive 150 may have its own analog-to-digital converter (ADC), configured to digitize an analog signal representing the energy of an incident radiating particle into a digital signal, or to digitize an analog signal representing the total energy of multiple incident radiating particles into a digital signal. Primitives 150 may be configured to operate in parallel. For example, while one primitive 150 is measuring an incident radiating particle, another primitive 150 may be waiting for the radiating particle to arrive. Primitives 150 need not be individually addressable.
[0028] The radiation detector 100 described herein can be applied to applications such as X-ray telescopes, X-ray mammography, industrial X-ray defect detection, X-ray microscopy or microradiography, X-ray casting inspection, X-ray non-destructive testing, X-ray weld inspection, and X-ray digital subtraction angiography. It may also be suitable to use the radiation detector 100 in place of photographic plates, photographic films, PSP plates, X-ray image intensifiers, scintillators, or other semiconductor X-ray detectors.
[0029] FIG. 2A schematically shows a simplified cross-sectional view of the radiation detector of FIG. 1 according to an embodiment along line 2A-2A. More specifically, the radiation detector 100 may include a radiation absorption layer 110 and an electronics layer 120 (e.g., including one or more ASICs 122 or dedicated integrated circuits) for processing or analyzing electrical signals generated in the radiation absorption layer 110 by incident radiation. The radiation detector 100 may or may not include a scintillator (not shown). The radiation absorption layer 110 may contain a semiconductor material, such as silicon, germanium, GaAs, CdTe, CdZnTe, or combinations thereof. The semiconductor material may have a high-quality attenuation coefficient for the radiation of interest. FIG. 2B schematically shows a top view of the radiation detector 100 of FIG. 2A according to an embodiment. In FIG. 2B, as an example, the electronics layer 120 of the radiation detector 100 may include six ASICs 122. Typically, the electronics layer 120 of the radiation detector 100 may include one or more ASICs 122.
[0030] As an example, FIG. 2C schematically shows a detailed cross-sectional view of the radiation detector 100 of FIG. 1 along line 2A-2A. More specifically, the radiation absorption layer 110 may include one or more diodes (e.g., pin or pn) formed by one or more discrete regions 114 of a first doped region 111 and a second doped region 113. The second doped region 113 may be separated from the first doped region 111 by an optional intrinsic region 112. The discrete regions 114 may be separated from each other by either the first doped region 111 or the intrinsic region 112. The first doped region 111 and the second doped region 113 may have opposite types of doping (e.g., region 111 is p-type and region 113 is n-type, or region 111 is n-type and region 113 is p-type). In the example of FIG. 2C, each discrete region 114 of the second doped region 113 forms a diode with the first doped region 111 and the optional intrinsic region 112. That is, in the example of Figure 2C, the radiation absorbing layer 110 has multiple diodes (more specifically, seven diodes correspond to seven elements 150 in a column of the array in Figure 1; for simplicity, only two of the elements 150 are labeled in Figure 2C). The multiple diodes may have an electrode 119A as a common (shared) electrode. The first doped region 111 may also have discrete portions.
[0031] Electronics layer 120 may include an electronic system 121 suitable for processing or interpreting signals generated by radiation incident on radiation-absorbing layer 110. Electronics system 121 may include analog circuitry such as filter networks, amplifiers, integrators, and comparators, or digital circuitry such as microprocessors and memory. Electronics system 121 may include one or more ADCs (analog-to-digital converters). Electronics system 121 may include elements shared by primitives 150 or elements dedicated to a single primitive 150. For example, electronics system 121 may include amplifiers dedicated to each primitive 150 and microprocessors shared among all primitives 150. Electronics system 121 may be electrically connected to primitives 150 via vias 131. The space between vias may be filled with filler material 130, which may increase the mechanical stability of the connection between electronics layer 120 and radiation-absorbing layer 110. Other bonding techniques may connect electronics system 121 to primitives 150 without using vias 131.
[0032] When radiation from a radiation source (not shown) impacts the radiation-absorbing layer 110 of a diode, the radiation particles can be absorbed and generate one or more charge carriers (e.g., electrons, holes) through various mechanisms. The charge carriers can drift to an electrode of one of the diodes under an electric field. This electric field can be an external electric field. Electrical contacts 119B can include discrete portions, each of which is in electrical contact with a discrete region 114. The term "electrical contact" can be used interchangeably with the word "electrode." In embodiments, charge carriers can drift in various directions such that charge carriers generated by a single radiation particle are substantially not shared by two different discrete regions 114 (here, "substantially not shared" means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow to a different discrete region 114 compared to the remaining charge carriers). Charge carriers generated by radiation particles incident around a coverage area of one of these discrete regions 114 are substantially not shared with the other of these discrete regions 114. The primitive 150 associated with discrete region 114 can be a region surrounding discrete region 114 in which substantially all (greater than 98%, greater than 99.5%, greater than 99.9%, or greater than 99.99%) of the charge carriers generated by incident radiating particles flow toward discrete region 114. That is, less than 2%, less than 1%, less than 0.1%, or less than 0.01% of these charge carriers flow through primitive 150.
[0033] Figure 2D schematically illustrates a detailed cross-sectional view along line 2A-2A of the radiation detector 100 of Figure 1 according to an alternative embodiment. More specifically, the radiation absorbing layer 110 may comprise resistors made of semiconductor materials such as silicon, germanium, GaAs, CdTe, CdZnTe, or combinations thereof, but not diodes. This semiconductor material may have a high-quality attenuation coefficient for the radiation of interest. In an embodiment, the electronics layer 120 of Figure 2D is structurally and functionally similar to the electronics layer 120 of Figure 2C.
[0034] When radiation impacts the radiation-absorbing layer 110, which includes a resistor but not a diode, it can be absorbed and generate one or more charge carriers through various mechanisms. The radiating particle can generate 10 to 100,000 charge carriers. These charge carriers can drift to electrical contacts 119A and 119B under an electric field. This electric field can be an external electric field. Electrical contact 119B can include discrete portions. In embodiments, charge carriers can drift in various directions such that charge carriers generated by a single radiating particle are substantially not shared by the two different discrete portions of electrical contact 119B (here, "substantially not shared" means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow to a different discrete portion compared to the remaining charge carriers). Charge carriers generated by radiating particles incident on the coverage area of one of these discrete portions of electrical contact 119B are substantially not shared with the other of these discrete portions of electrical contact 119B. The primitive 150 associated with a discrete portion of the electrical contact 119B can be a region surrounding the discrete portion, in which substantially all (greater than 98%, greater than 99.5%, greater than 99.9%, or greater than 99.99%) of the charge carriers generated by incident radiant particles flow toward the discrete portion of the electrical contact 119B. That is, less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow through a primitive associated with a discrete portion of the electrical contact 119B.
[0035] Radiation detector packaging
[0036] FIG. 3A schematically shows a top view of a radiation detector package 300 according to an embodiment. Specifically, the radiation detector package 300 may include a set of printed circuit boards (set PCB) 310 and four radiation detectors 100 mounted on the set PCB 310. Typically, the radiation detector package 300 may include any number of radiation detectors 100. As used herein, the term "PCB" is not limited to a particular material. For example, a PCB may include semiconductors. For clarity, wiring between the four radiation detectors 100 and the set PCB 310 is not shown. The set PCB 310 may have a rectangular shape. Typically, the set PCB 310 may have any shape.
[0037] The PCB 310 may have an area 305 not covered by the radiation detector 100 (e.g., for accommodating input / output ports 320). Each radiation detector 100 of the radiation detector package 300 may have an effective area 190 where the element 150 (FIG. 1) is located. Each radiation detector 100 of the radiation detector package 300 may have a peripheral area 195 near its edge. The peripheral area 195 of the radiation detector 100 does not have the element 150 and therefore does not detect radiation particles incident thereon. FIG. 3B schematically shows a cross-sectional view of the radiation detector package 300 of FIG. 3A according to an embodiment along line 3B-3B.
[0038] In an embodiment, the radiation detector 100 of FIG3A can be rotated counterclockwise to obtain the radiation detector package 300 of FIG3C. In FIG3C, for simplicity, only the effective area 190 of the radiation detector 100 is shown.
[0039] Image sensor
[0040] FIG4A schematically shows a top view of an image sensor 490 according to an embodiment. Specifically, the image sensor 490 may include a system PCB 410 and three radiation detector packages 300 of FIG3C mounted on a mounting surface 412 of the system PCB 410. Typically, the image sensor 490 may include any number of radiation detector packages 300, and each radiation detector package 300 may have any number of radiation detectors 100. In other words, the number of radiation detectors 100 in the radiation detector packages 300 need not be the same. For simplicity, only the effective area 190 of the radiation detectors 100 is shown. For clarity, the electrical connections between the system PCB 410 and the three radiation detector packages 300 are not shown.
[0041] In an embodiment, as shown in FIG4A, the effective regions 190 of each radiation detector package 300 of the image sensor 490 may not overlap in the normal direction (not shown) perpendicular to the mounting surface 412 of the system PCB 410. In other words, for each radiation detector package 300 of the image sensor 490, two effective regions 190 of the radiation detector 100 of the radiation detector package 300 do not overlap in the normal direction. In FIG4A, the mounting surface 412 is parallel to the page; and the normal direction is perpendicular to the page.
[0042] In an embodiment, as shown in Figures 4A and 4B, the three radiation detector packages 300 may overlap in the normal direction. Specifically, the left portion (including the input / output port 320) of the middle radiation detector package 300 may be below the left radiation detector package 300 and is not shown for simplicity. Similarly, the left portion (including the input / output port 320) of the right radiation detector package 300 may be below the middle radiation detector package 300 and is not shown for simplicity. Figure 4B schematically shows a cross-sectional view of the image detector 490 of Figure 4A according to an embodiment along line 4B-4B.
[0043] In an embodiment, referring to Figures 4A and 4B, the dead zone 488 of the image sensor 490 may include any area of the image sensor 490 not covered by the effective area 190 of the radiation detector 100. The dead zone 488 cannot detect incident radiation. However, the image sensor 490 may capture multiple partial images of an object or scene (not shown) one by one, and these captured partial images may then be stitched together to form a complete image of the object or scene.
[0044] In an embodiment, the image sensor 490 may translate (i.e., move such that all portions of the image sensor 490 travel in the same direction without rotation or change in shape) while scanning an object or scene (i.e., capturing multiple partial images of the object or scene one by one). This translation direction of the image sensor 490 may be referred to as the scanning direction. In an embodiment, as shown in FIG4A, the image sensor 490 may be configured to scan in an eastward direction (i.e., the 3 o'clock direction), and the three groups of PCBs 310 may be arranged as columns extending in the scanning direction (i.e., in the eastward direction).
[0045] In an embodiment, as shown in Figures 4A and 4B, the three groups of PCBs 310 can overlap in the normal direction, such that all three groups of PCBs 310 form a single printed circuit board in the normal direction, and a plane parallel to the normal direction and parallel to the scanning direction (i.e., eastward) intersects all three groups of PCBs. Here, "the groups of PCBs 310 forming a single printed circuit board in the normal direction" means that there are no gaps between them when viewed along the normal direction.
[0046] In an embodiment, as shown in FIG4B, the input / output port 320 on the middle group PCB 310 can be sandwiched between the middle group PCB 310 and the left group PCB 310. In an embodiment, as shown in FIG4B, the input / output port 320 on the middle group PCB 310 can overlap with the effective area 190 on the left group PCB 310 in the normal direction.
[0047] In summary, an image sensor (e.g., image sensor 490 of FIG4A and FIG4B) has been described above, which includes: (A) a system PCB (e.g., system PCB 410); (B) M group PCBs, including group PCB(i) mounted on a mounting surface (e.g., mounting surface 412) of the system PCB, i=1, ..., M (e.g., group PCB(1), group PCB(2) and group PCB(3) of FIG4A and FIG4B); and (C) for i=1, ..., M, Ni radiation detectors mounted on group PCB(i) (e.g., N1=4 radiation detectors 100 mounted on group PCB(1); N2=4 radiation detectors 100 mounted on group PCB(2); and N3=4 radiation detectors 100 mounted on group PCB(3).
[0048] Furthermore, in an embodiment, the image sensor may be configured to scan the scene in a scanning direction (e.g., the scanning direction may be eastward, i.e., at the 3 o'clock position).
[0049] Furthermore, for each group PCB(i) (e.g., group PCB(1), group PCB(2), and group PCB(3) of Figures 4A and 4B), there is no plane that (A) is parallel to the normal direction of the mounting surface of the system PCB (e.g., perpendicular to the direction of page 4A), (B) is parallel to the scanning direction (e.g., eastward), (C) divides all effective areas of the Ni radiation detectors (e.g., 4 effective areas 190) into two groups of effective areas, and (D) does not intersect with any effective area of all effective areas of the Ni radiation detectors. This condition (i.e., there is no such plane that…) ensures that when the image sensor 490 scans the scene in the scanning direction, the effective area 190 of each radiation detector package 300 of the image sensor 490 can scan an area without leaving any unscanned areas in that area.
[0050] This can be explained with reference to FIG3C as follows. If the scanning direction is in the 2 o'clock direction (arrow 330), then the gap 340 between the four effective regions 190 of the radiation detector package 300 will result in unscanned regions existing in the area swept by the four effective regions 190. This situation occurs when the above condition is not met (i.e., there is no such plane, ...). Alternatively, if the scanning direction is in the 3 o'clock direction (arrow 350), then there will be no unscanned regions in the area swept by the four effective regions 190. This alternative situation occurs when the above condition is met (i.e., there is no such plane, ...).
[0051] FIG4C schematically shows a perspective view of an imaging system 400 according to an embodiment. Specifically, the imaging system 400 may include an image sensor 490, a radiation source 450, and a mask 470 as shown in FIG4A and FIG4B. In FIG4C, for simplicity, details of the image sensor 490 are not shown. In the embodiment, for radiation from the radiation source 450 incident on the mask 470, only radiation incident on the mask window 472 of the mask 470 is allowed to pass through the mask 470, thereby obtaining a radiation beam 452 with a beam boundary 452b.
[0052] In an embodiment, the imaging system 400 may be arranged such that, when the image sensor 490 scans a scene (which may include an object 460), the beam boundary 452b of the radiation beam 452 does not intersect with any effective region 190 of all effective regions 190 of the image sensor 490. In an embodiment, as shown in FIG4C, the radiation of the radiation beam 452 may be aimed at various points of all effective regions 190 of the image sensor 490. In other words, various points of all effective regions 190 of the image sensor 490 are aimed at by the radiation beam 452.
[0053] In an embodiment, referring to FIG5, in each of the three radiation detector packages 300 of the image sensor 490, the effective regions 190 may overlap in the normal direction. In an embodiment, as shown in FIG5, the effective regions 190 of each radiation detector package 300 of the image sensor 490 may overlap, such that all effective regions 190 of each radiation detector package 300 form a single effective region in the normal direction. Here, all effective regions 190 forming a single effective region in the normal direction means that there are no gaps between the effective regions 190 when viewed along the normal direction. Furthermore, in an embodiment, as shown in FIG5, for each radiation detector package 300 of the image sensor 490, a plane (not shown) parallel to the normal direction and perpendicular to the scanning direction intersects all effective regions 190 of the radiation detector 100 of the radiation detector element 300.
[0054] In an embodiment, the three radiation detector packages 300 of FIG. 5 can be arranged more closely together to obtain the image sensor 490 of FIG. 6. In FIG. 6, for simplicity, only the effective areas 190 of the three radiation detector packages 300 of the image sensor 490 are shown. In an embodiment, as shown in FIG. 6, all 12 effective areas 190 of the three radiation detector packages 300 form one effective area in the normal direction.
[0055] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for illustrative purposes and are not intended to be limiting; the true scope and spirit are indicated by the appended claims. [Simplified Explanation of the Diagram]
[0023] FIG1 schematically illustrates a radiation detector according to an embodiment. FIG2A and FIG2B schematically illustrate simplified diagrams of a radiation detector according to an embodiment. FIG2C schematically illustrates a detailed cross-sectional view of a radiation detector according to an embodiment. FIG2D schematically illustrates a detailed cross-sectional view of a radiation detector according to an alternative embodiment. FIG3A to FIG3C schematically illustrate a radiation detector package including multiple radiation detectors according to different embodiments. FIG4A and FIG4B schematically illustrate an image sensor including a package of multiple radiation detectors according to an embodiment. FIG4C schematically illustrates a perspective view of an imaging system according to an embodiment. FIG5 illustrates an image sensor of FIG4A and FIG4B according to an alternative embodiment. FIG6 illustrates an image sensor of FIG4A and FIG4B according to yet another alternative embodiment.
Claims
1. An imaging system, comprising: An image sensor includes: a system printed circuit board (system PCB); M groups of printed circuit boards (groups PCB(i), i=1, ..., M) mounted on a mounting surface of the system PCB; and Ni radiation detectors mounted on the groups PCB(i) for i=1, ..., M, where M and Ni are integers greater than 1, i=1, ..., M, wherein the image sensor is configured to scan a scene in a scanning direction, and wherein, for each group PCB(i), there is no plane that (A) is parallel to the normal direction of the mounting surface of the system PCB, (B) is parallel to the scanning direction, (C) divides all effective areas of the Ni radiation detectors into two groups of effective areas, and (D) does not intersect any effective area of all effective areas of the Ni radiation detectors.
2. The imaging system as claimed in claim 1, wherein, All Ni are identical, where i = 1, ..., M.
3. The imaging system as claimed in claim 1, wherein, The M groups of PCBs and the system PCB include semiconductors.
4. The imaging system as claimed in claim 1, wherein, Each of the M groups of PCBs has a rectangular shape.
5. The imaging system as claimed in claim 1, wherein, The M groups of PCBs are arranged in columns extending in the scanning direction.
6. The imaging system as claimed in claim 1, wherein, All effective regions of all Ni radiation detectors overlap in the normal direction, where i = 1, ..., M, so that all effective regions of all Ni radiation detectors form one effective region in the normal direction, where i = 1, ..., M.
7. The imaging system of claim 1 further includes a radiation source configured to generate a radiation beam whose boundary does not intersect any of the effective regions of all the Ni radiation detectors when the image sensor scans the scene, where i = 1, ..., M.
8. The imaging system as claimed in claim 7, wherein, The radiation beam is aimed at points in all effective regions of all Ni radiation detectors, where i = 1, ..., M.
9. The imaging system of claim 7 further includes a mask that allows some radiation from the radiation source to pass through the mask to obtain the radiation beam.
10. The imaging system as claimed in claim 1, wherein, For each group PCB(i), no two effective regions of the Ni radiation detectors overlap in the normal direction, where i = 1, ..., M.
11. The imaging system as claimed in claim 1, wherein, For each group of PCB(i), (A) the Ni radiation detectors of the group of PCB(i) overlap in the normal direction, such that all effective regions of the Ni radiation detectors form one effective region in the normal direction, and (B) a plane parallel to the normal direction and perpendicular to the scanning direction intersects all effective regions of the Ni radiation detectors, where i = 1, ..., M.
12. The imaging system as claimed in claim 1, wherein, The M groups of PCBs overlap in the normal direction, thereby forming a single printed circuit board in the normal direction, wherein a plane parallel to the normal direction and parallel to the scanning direction intersects with all the M groups of PCBs.
13. The imaging system as claimed in claim 12 further includes an input / output port on each of the M groups of PCBs.
14. The imaging system as claimed in claim 13, wherein, The input / output ports on the first group of the M groups of PCBs are sandwiched between the first group of PCBs and the second group of PCBs.
15. The imaging system as claimed in claim 13, wherein, The input / output ports on the first group of the M groups of PCBs overlap with the effective area on the second group of the M groups of PCBs in the normal direction.
16. The imaging system as claimed in claim 1, wherein, For each group of PCBs (i), each of the Ni radiation detectors on the group of PCBs (i) includes: (A) a radiation absorption layer and (B) an electronic device layer including a plurality of dedicated integrated circuits (ASICs), where i = 1, ..., M.
17. The imaging system as claimed in claim 16, wherein, The radiation-absorbing layer and the electronic device layer are electrically connected to each other through vias.
18. The imaging system as claimed in claim 16, wherein, The radiation-absorbing layer comprises multiple diodes.
19. The imaging system as claimed in claim 16, wherein, The radiation-absorbing layer includes a semiconductor.
20. The imaging system as claimed in claim 16, wherein, The electronic device layer includes an electronic system configured to process signals generated by radiation incident on the radiation-absorbing layer.