Double-layer X-ray detector and preparation method thereof

Abstract

The double-layer X-ray detector comprises a metal filtering layer, an upper-layer detector and a lower-layer detector. The metal filtering layer comprises a first surface and a second surface which are oppositely arranged. The upper-layer detector comprises an upper-layer substrate, an upper-layer scintillator and an upper-layer packaging reflecting film which are arranged in sequence; the upper-layer substrate is arranged on the first surface of the metal filtering layer; the lower-layer detector comprises a lower-layer substrate, a lower-layer scintillator and a lower-layer packaging reflecting film which are arranged in sequence, and the lower-layer substrate is arranged on the second surface of the metal filtering layer. Wherein the upper-layer substrate and the lower-layer substrate are respectively provided with an extension part on the radial outer side of the metal filtering layer, and alignment marks are arranged on the extension parts. And the upper-layer detector and the lower-layer detector form a symmetrical stacked structure by taking the metal filtering layer as a center. And in the preparation process, performing alignment operation on the upper-layer detector and the lower-layer detector based on the alignment identifier, so that the upper-layer detector is aligned with the lower-layer detector. And the alignment precision can be effectively and reliably improved.

Description

Technical Field

[0001] This invention belongs to the field of X-ray detector technology, specifically, it relates to a dual-layer X-ray detector and its fabrication method. Background Technology

[0002] In modern medical imaging (such as X-ray examinations) and industrial non-destructive testing, the "dual-layer detector" is an advanced technology that can simultaneously capture both high-energy and low-energy X-ray signals. It not only reveals the shape of objects but also roughly distinguishes their atomic numbers (e.g., differentiating between bone and soft tissue). This technology is of great significance for improving diagnostic accuracy and testing precision.

[0003] However, traditional dual-layer detectors face several key technical challenges and limitations in their design and manufacturing, restricting further performance improvements. Traditional dual-layer detectors typically employ a "face-to-face" stacking method, where the photosensitive surfaces of both detectors face upwards. This structure necessitates a significant physical space (usually greater than 2 mm) between the upper and lower layers to accommodate the intermediate structure. Due to the gap between the layers and the fact that the X-ray source is a point source, according to the principles of optical projection, the image projected onto the lower detector will be slightly magnified and shifted compared to the upper image. This results in inaccurate alignment of corresponding "pixels" (the smallest units of an image) in the upper and lower images. To address this issue, existing technologies rely on complex software algorithms for "geometric correction" after imaging. This process not only increases computational burden but, more importantly, any algorithmic correction introduces errors and loses some of the image's true details, leading to a decrease in the spatial resolution (i.e., sharpness and detail reproduction capability) of the final "fused image." Precisely aligning the tens of millions of tiny pixels between the upper and lower layers during manufacturing is a significant challenge. Existing methods typically rely on coarse positioning of the detector's geometric contours, followed by placing markers within the imaging area for fine positioning via X-ray projection. This method has several drawbacks: First, it must be operated under X-ray conditions and utilizes electrical fixtures for imaging the upper and lower detector layers themselves, increasing process complexity and safety costs. Second, the accuracy of this indirect alignment method is limited, typically with an alignment error of around 100 micrometers (limited by the spatial resolution of the detector's own pixels), which is still too large for images requiring extreme spatial resolution. The traditional manufacturing sequence usually involves first fabricating all key components on the upper and lower detector layers separately (scintillator deposition and encapsulation are required before X-ray projection can be used), and then finally performing two-layer stacking and alignment. Summary of the Invention

[0004] In view of the problems existing in the prior art described above, this application provides a dual-layer X-ray detector and its preparation method, which can effectively and reliably improve alignment accuracy and enhance the spatial resolution and clarity of the final fused image.

[0005] To achieve the above and other related objectives, the present invention provides a dual-layer X-ray detector, comprising: A metal filter layer, comprising a first surface and a second surface disposed opposite to each other; The upper detector includes an upper substrate, an upper scintillator, and an upper encapsulation reflective film arranged sequentially, with the upper substrate disposed on the first surface of the metal filter layer; The lower-layer detector includes a lower-layer substrate, a lower-layer scintillator, and a lower-layer encapsulation reflective film arranged sequentially, with the lower-layer substrate disposed on the second surface of the metal filter layer; Both the upper and lower substrates have extensions on the radially outer side of the metal filter layer, and the upper and lower detectors form a symmetrical stacked structure with the metal filter layer as the center.

[0006] Optionally, the shortest distance between the upper and lower detectors is between 0.4 mm and 2 mm.

[0007] Optionally, both the upper and lower substrates are transparent substrates.

[0008] Optionally, an adhesive layer is provided between the upper substrate and the metal filter layer, and between the lower substrate and the metal filter layer.

[0009] Optionally, the extensions of the upper substrate and the lower substrate are provided with a plurality of corresponding alignment marks.

[0010] Optionally, the alignment accuracy of the upper pixel array of the upper substrate and the lower pixel array of the lower substrate within the effective imaging area is between 5 μm and 100 μm.

[0011] Another aspect of the present invention provides a method for fabricating a dual-layer X-ray detector, which includes the following steps: A metal filter layer is provided, including a first surface and a second surface disposed opposite to each other; An upper-layer detector is provided, comprising an upper-layer substrate, an upper-layer scintillator, and an upper-layer encapsulation reflective film arranged sequentially; A lower-layer detector is provided, comprising a lower-layer substrate, a lower-layer scintillator, and a lower-layer encapsulation reflective film arranged sequentially, wherein both the upper-layer substrate and the lower-layer substrate have extensions on the radially outer side of the metal filter layer; Multiple alignment marks are provided on the extensions of the upper and lower substrates; The upper detector is movably disposed on the first surface of the metal filter layer and / or the lower detector is movably disposed on the second surface of the metal filter layer; Based on the alignment marker, the upper and lower layer detectors will be aligned until they are in place, at which point the upper and lower layer detectors will be fixed in place.

[0012] Optionally, alignment operations can be performed on the upper and lower detectors in a visible light environment.

[0013] Another aspect of the present invention provides a method for fabricating a dual-layer X-ray detector, which includes the following steps: A metal filter layer is provided, including a first surface and a second surface disposed opposite to each other; An upper substrate and a lower substrate are provided, both of which have extensions on the radially outer side of the metal filter layer; Multiple alignment marks are provided on the extensions of the upper and lower substrates; The upper substrate is movably disposed on the first surface of the metal filter layer and / or the lower substrate is movably disposed on the second surface of the metal filter layer; Based on the alignment mark, the upper substrate and the lower substrate will be aligned until the upper substrate and the lower substrate are aligned, and then the upper substrate and the lower substrate will be fixed. An upper scintillator and an upper encapsulation reflective film are sequentially disposed on an upper substrate to form an upper detector; A lower-layer scintillator and a lower-layer encapsulation reflective film are sequentially disposed on the lower-layer substrate to form a lower-layer detector.

[0014] Optionally, alignment operations can be performed on the upper and lower substrates under visible light conditions.

[0015] As described above, the dual-layer X-ray detector and its fabrication method provided by the present invention have at least the following beneficial technical effects: The dual-layer X-ray detector of the present invention includes a metal filter layer, an upper detector, and a lower detector. The metal filter layer includes a first surface and a second surface disposed opposite to each other. The upper detector includes an upper substrate, an upper scintillator, and an upper encapsulation reflective film disposed sequentially, with the upper substrate disposed on the first surface of the metal filter layer. The lower detector includes a lower substrate, a lower scintillator, and a lower encapsulation reflective film disposed sequentially, with the lower substrate disposed on the second surface of the metal filter layer. Both the upper and lower substrates have extensions radially outward from the metal filter layer, and alignment marks are provided on the extensions. The upper and lower detectors form a symmetrical stacked structure with the metal filter layer as the center. During fabrication, alignment operations are performed on the upper and lower detectors based on the alignment marks to align them. This effectively and reliably improves alignment accuracy, enhancing the spatial resolution and clarity of the final fused image. Attached Figure Description

[0016] Figure 1 The diagram shown is a structural schematic of a dual-layer X-ray detector provided in an embodiment of the present invention.

[0017] Figure 2 The diagram shown is a schematic diagram of the upper substrate provided in an embodiment of the present invention.

[0018] Figure 3 The diagram shown is a schematic diagram of the structure of the lower substrate provided in an embodiment of the present invention.

[0019] Figure 4 The image shown is a top view of the upper substrate, metal filter layer, and lower substrate provided in an embodiment of the present invention after positioning.

[0020] Figure 5 The diagram shown is a flowchart of the fabrication method of the dual-layer X-ray detector provided in Embodiment 2 of the present invention.

[0021] Figure 6 The diagram shown is a flowchart of the fabrication method of the dual-layer X-ray detector provided in Embodiment 3 of the present invention.

[0022] Figure Labels 1. Upper detector; 11. Upper substrate; 111. Extension; 12. Upper pixel array; 13. Upper scintillator; 14. Upper encapsulation reflective film; 2. Metal filter layer; 21. First surface; 22. Second surface; 3. Lower detector; 31. Lower substrate; 32. Lower pixel array; 33. Lower scintillator; 34. Lower encapsulation reflective film; 4. Alignment mark. Detailed Implementation

[0023] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0024] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Although the illustrations only show components related to the present invention and are not drawn according to the actual number, shape and size of the components, the shape, quantity, positional relationship and proportion of each component can be arbitrarily changed under the premise of realizing the technical solution of this invention, and the layout of the components may also be more complex.

[0025] Example 1 This embodiment provides a dual-layer X-ray detector, referencing... Figures 1 to 4 It includes a metal filter layer 2, an upper detector 1, and a lower detector 3.

[0026] Reference Figure 1 The metal filter layer 2 includes a first surface 21 and a second surface 22 disposed opposite to each other. The metal filter layer 2 is preferably made of copper or aluminum and is used to selectively filter X-rays of different energies to achieve energy spectrum separation. In this embodiment, the thickness of the metal filter layer 2 is between 300 μm and 800 μm, which ensures sufficient energy spectrum separation while avoiding excessive attenuation of the X-ray signal. In an optional embodiment of this invention, the thickness of the metal filter layer 2 is 300 μm.

[0027] Reference Figure 1The upper detector 1 includes an upper substrate 11, an upper scintillator 13, and an upper encapsulation reflective film 14 arranged sequentially. The upper substrate 11 is disposed on the first surface 21 of the metal filter layer 2. The upper substrate 11 includes an upper pixel array 12. An adhesive layer (not shown in the figures) is provided between the upper substrate 11 and the metal filter layer 2. In an optional embodiment of this example, the adhesive layer is a slow-curing liquid adhesive. In this example, the thickness of the upper substrate 11 is between 20 μm and 700 μm. The upper substrate 11 can be a flexible plastic substrate or a rigid glass substrate, and there is no limitation. In this example, the upper substrate 11 is a transparent substrate. In an optional embodiment of this example, the upper substrate 11 is a flexible plastic substrate. The thickness of the upper pixel array 12 is greater than 1 μm, and it can convert the visible light signal converted by the upper scintillator 13 into an electrical signal. The thickness of the upper scintillator 13 is between 200 μm and 700 μm, and it is used to convert incident X-rays into visible light. The thickness of the upper encapsulation reflective film 14 is between 50 μm and 100 μm. Its function is to improve the backlight collection efficiency and prevent damage to the internal scintillator from external air. The thickness of the adhesive layer is between 10 μm and 100 μm, which ensures the adhesive strength while avoiding affecting the overall structural compactness due to excessive thickness.

[0028] Reference Figure 1 The lower-layer detector 3 includes a lower-layer substrate 31, a lower-layer scintillator 33, and a lower-layer encapsulated reflective film 34, which are sequentially disposed. The lower-layer substrate 31 is disposed on the second surface 22 of the metal filter layer 2. The lower-layer substrate 31 includes a lower-layer pixel array 32. An adhesive layer (not shown in the figures) is provided between the lower-layer substrate 31 and the metal filter layer 2. In an optional embodiment of this example, the adhesive layer is also a slow-curing liquid adhesive. In this example, the thickness of the lower-layer substrate 31 is also between 20 μm and 700 μm. The lower-layer substrate 31 is also a transparent substrate. The lower-layer substrate 31 can be a flexible plastic substrate or a rigid glass substrate, which is not limited here. In an optional embodiment of this example, the lower-layer substrate 31 is a flexible plastic substrate. The thickness of the lower-layer pixel array 32 is greater than 1 μm. The thickness of the lower-layer scintillator 33 is between 200 μm and 700 μm. The thickness of the lower-layer encapsulated reflective film 34 is between 50 μm and 100 μm. The thickness of the adhesive layer ranges from 10 μm to 100 μm.

[0029] Both the upper substrate 11 and the lower substrate 31 have extensions 111 on the radially outer side of the metal filter layer 2, providing space for the arrangement of the alignment marks 4. Specifically, refer to... Figure 2 and Figure 3Multiple alignment marks 4 corresponding to each other are provided on the extension 111 of the upper substrate 11 and the extension 111 of the lower substrate 31. These alignment marks 4 are located outside the effective imaging area, and high-precision alignment can be achieved by a microscopic measurement optical alignment system, while avoiding interference from the metal filter layer 2 on the identification of the alignment marks 4.

[0030] Reference Figure 1 The upper detector 1 and the lower detector 3 form a symmetrical stacked structure with the metal filter layer 2 as the center. In this symmetrical stacked structure, the shortest distance between the upper detector 1 and the lower detector 3 is between 0.4 mm and 2 mm. In an optional embodiment of this example, the shortest distance between the upper detector 1 and the lower detector 3 is 0.4 mm, which is a significant improvement compared to the spacing of more than 2 mm in traditional structures.

[0031] Reference Figure 1 Through the above structural design, this embodiment achieves an alignment accuracy of 5 μm to 100 μm between the upper pixel array 12 and the lower pixel array 32 within the effective imaging area. In an optional embodiment of this invention, the alignment accuracy between the upper pixel array 12 and the lower pixel array 32 within the effective imaging area is 10 μm, which is a significant improvement compared to the 100 μm alignment accuracy of traditional technologies. This greatly improves the fusion quality of the two-layer images, increases spatial resolution, and reduces or even eliminates the need for subsequent image geometric correction.

[0032] Example 2 This embodiment provides a method for fabricating a dual-layer X-ray detector, used to fabricate the dual-layer X-ray detector described in Embodiment 1, referring to... Figures 1 to 5 This includes the following steps: S100: A metal filter layer 2 is provided, including a first surface 21 and a second surface 22 disposed opposite to each other; S200: Provides an upper-layer detector 1, including an upper-layer substrate 11, an upper-layer scintillator 13 and an upper-layer encapsulation reflective film 14 arranged sequentially; S300: Provides a lower layer detector 3, including a lower layer substrate 31, a lower layer scintillator 33 and a lower layer encapsulation reflective film 34 arranged sequentially, with the upper layer substrate 11 and the lower layer substrate 31 both having an extension 111 on the radially outer side of the metal filter layer 2; S400: A plurality of corresponding alignment marks 4 are provided on the extensions 111 of the upper substrate 11 and the lower substrate 31; Alignment markers 4 are formed using the same photolithography process as the pixel array and are distributed in a mirror-symmetrical manner on the upper substrate 11 and the lower substrate 31. In an optional embodiment of this example, reference is made to... Figure 2 and Figure 3 Four alignment marks 4 are respectively provided on the extension 111 of the upper substrate 11 and the lower substrate 31.

[0033] S500: The upper detector 1 is movably disposed on the first surface 21 of the metal filter layer 2 and / or the lower detector 3 is movably disposed on the second surface 22 of the metal filter layer 2; Reference Figure 1 Optionally, before setting the upper detector 1 and the lower detector 3, the metal filter layer 2 needs to undergo precision pretreatment. A plasma cleaning process is used to remove the surface oxide layer and organic contaminants. Chemical mechanical polishing (CMP) is used to control the surface roughness Ra to ≤1 μm to optimize the adhesion of the subsequent adhesive layer. In one optional embodiment of this example, both the upper detector 1 and the lower detector 3 are set on the metal filter layer 2 via an adhesive layer. The adhesive material is preferably a slow-curing liquid adhesive, which remains uncured or semi-cured in the initial state to allow for subsequent fine-tuning and alignment. During subsequent alignment adjustments, both the upper detector 1 and the lower detector 3 can be adjusted simultaneously. In another optional embodiment of this example, the upper detector 1 is movably set on the first surface 21 of the metal filter layer 2, and the lower detector 3 is fixedly set on the second surface 22 of the metal filter layer 2. During subsequent alignment adjustments, the upper detector 1 is adjusted for alignment. In another optional embodiment of this invention, the upper detector 1 is fixedly disposed on the first surface 21 of the metal filter layer 2, and the lower detector 3 is movably disposed on the second surface 22 of the metal filter layer 2. During subsequent alignment adjustments, the lower detector 3 is adjusted for alignment.

[0034] S600: Based on the alignment identifier 4, the upper layer detector 1 and the lower layer detector 3 will be aligned until the upper layer detector 1 and the lower layer detector 3 are aligned, and then the upper layer detector 1 and the lower layer detector 3 will be fixed.

[0035] In this embodiment, refer to Figures 1 to 4 The upper detector 1 and lower detector 3 are aligned under visible light conditions. The visible light alignment system, with its superior microscopic ranging optical characteristics, provides higher image resolution and more precise positioning capabilities. Compared to traditional X-ray alignment methods, this process not only eliminates stringent radiation protection requirements and significantly simplifies equipment configuration and reduces special requirements for the operating environment, but also, due to the wider availability and stability of visible light equipment, it significantly improves production efficiency and reduces manufacturing costs. For specific implementation, refer to... Figure 4Both the upper substrate 11 and the lower substrate 31 are made of transparent material, allowing for alignment as follows: The upper detector 1 and the lower detector 3 are placed opposite each other, ensuring that the alignment marks 4 on the extension 111 of the upper substrate 11 and the extension 111 of the lower substrate 31 are perfectly aligned in the field of view, forming a precise mirror symmetry. Once the alignment accuracy meets the design requirements, the three-layer structure is permanently fixed by pre-curing the adhesive layers between the upper substrate 11 and the metal filter layer 2, and between the lower substrate 31 and the metal filter layer 2. The curing method is selected based on the properties of the adhesive material, with ultraviolet light curing being preferred. This method allows for rapid curing while maintaining positional accuracy, ensuring that the final dual-layer X-ray detector has a stable and reliable structure and excellent alignment accuracy.

[0036] Example 3 This embodiment provides a method for fabricating a dual-layer X-ray detector, used to fabricate the dual-layer X-ray detector described in Embodiment 1, referring to... Figures 1 to 4 and Figure 6 This includes the following steps: S100: A metal filter layer 2 is provided, including a first surface 21 and a second surface 22 disposed opposite to each other; S200: An upper substrate 11 and a lower substrate 31 are provided, and both the upper substrate 11 and the lower substrate 31 have extensions 111 on the radially outer side of the metal filter layer 2. S300: A plurality of corresponding alignment marks 4 are provided on the extensions 111 of the upper substrate 11 and the lower substrate 31; S400: The upper substrate 11 is movably disposed on the first surface 21 of the metal filter layer 2 and / or the lower substrate 31 is movably disposed on the second surface 22 of the metal filter layer 2; S500: Based on the alignment mark 4, an alignment operation will be performed on the upper substrate 11 and the lower substrate 31 until the upper substrate 11 and the lower substrate 31 are aligned, and then the upper substrate 11 and the lower substrate 31 will be fixed. S600: An upper scintillator 13 and an upper encapsulation reflective film 14 are sequentially disposed on the upper substrate 11 to form an upper detector 1; S700: A lower scintillator 33 and a lower encapsulation reflective film 34 are sequentially disposed on the lower substrate 31 to form a lower detector 3.

[0037] In this embodiment, refer to Figures 1 to 4Similarly, alignment operations are performed on the upper substrate 11 and the lower substrate 31 under visible light conditions, and the alignment method is similar to that in Embodiment 2. The difference is that in this embodiment, the upper substrate 11 and the lower substrate 31 without scintillators and encapsulated reflective films are first aligned. After alignment is completed, other structures of the upper detector 1 and the lower detector 3 are set on the upper substrate 11 and the lower substrate 31.

[0038] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A dual-layer X-ray detector, characterized in that, include: A metal filter layer, comprising a first surface and a second surface disposed opposite to each other; The upper detector includes an upper substrate, an upper scintillator, and an upper encapsulation reflective film arranged sequentially, wherein the upper substrate is disposed on the first surface of the metal filter layer; The lower-layer detector includes a lower-layer substrate, a lower-layer scintillator, and a lower-layer encapsulation reflective film arranged sequentially, wherein the lower-layer substrate is disposed on the second surface of the metal filter layer; The upper substrate and the lower substrate both have extensions on the radially outer side of the metal filter layer, and the upper detector and the lower detector form a symmetrical stacked structure with the metal filter layer as the center.

2. The dual-layer X-ray detector according to claim 1, characterized in that, The shortest distance between the upper-layer detector and the lower-layer detector is between 0.4 mm and 2 mm.

3. The dual-layer X-ray detector according to claim 1, characterized in that, Both the upper substrate and the lower substrate are transparent substrates.

4. The dual-layer X-ray detector according to claim 1, characterized in that, An adhesive layer is provided between the upper substrate and the metal filter layer, and between the lower substrate and the metal filter layer.

5. The dual-layer X-ray detector according to claim 1, characterized in that, The extension portions of the upper substrate and the lower substrate are provided with a plurality of corresponding alignment marks.

6. The dual-layer X-ray detector according to claim 1, characterized in that, The alignment accuracy between the upper pixel array of the upper substrate and the lower pixel array of the lower substrate within the effective imaging area is between 5 μm and 100 μm.

7. A method for fabricating a dual-layer X-ray detector, characterized in that, The method for preparing a dual-layer X-ray detector as described in any one of claims 1 to 6 comprises the following steps: A metal filter layer is provided, including a first surface and a second surface disposed opposite to each other; An upper-layer detector is provided, comprising an upper-layer substrate, an upper-layer scintillator, and an upper-layer encapsulation reflective film arranged sequentially; A lower-layer detector is provided, comprising a lower-layer substrate, a lower-layer scintillator, and a lower-layer encapsulation reflective film arranged sequentially, wherein both the upper-layer substrate and the lower-layer substrate have extensions on the radially outer side of the metal filter layer; A plurality of corresponding alignment marks are provided on the extension portions of the upper substrate and the lower substrate; The upper detector is movably disposed on the first surface of the metal filter layer and / or the lower detector is movably disposed on the second surface of the metal filter layer; Based on the alignment identifier, an alignment operation will be performed on the upper layer detector and the lower layer detector until the upper layer detector and the lower layer detector are aligned, and then the upper layer detector and the lower layer detector will be fixed.

8. The method for fabricating a dual-layer X-ray detector according to claim 7, characterized in that, Alignment operations are performed on the upper-layer detector and the lower-layer detector under visible light conditions.

9. A method for fabricating a dual-layer X-ray detector, characterized in that, The method for preparing a dual-layer X-ray detector as described in any one of claims 1 to 6 comprises the following steps: A metal filter layer is provided, including a first surface and a second surface disposed opposite to each other; An upper substrate and a lower substrate are provided, wherein both the upper substrate and the lower substrate have extensions on the radially outer side of the metal filter layer; A plurality of corresponding alignment marks are provided on the extension portions of the upper substrate and the lower substrate; The upper substrate is movably disposed on the first surface of the metal filter layer and / or the lower substrate is movably disposed on the second surface of the metal filter layer; Based on the alignment mark, an alignment operation will be performed on the upper substrate and the lower substrate until the upper substrate and the lower substrate are aligned, and then the upper substrate and the lower substrate will be fixed. An upper scintillator and an upper encapsulation reflective film are sequentially disposed on the upper substrate to form an upper detector; A lower-layer scintillator and a lower-layer encapsulation reflective film are sequentially disposed on the lower-layer substrate to form a lower-layer detector.

10. The method for fabricating a dual-layer X-ray detector according to claim 9, characterized in that, Alignment operations are performed on the upper and lower substrates under visible light conditions.

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