High-performance ultraviolet imaging detector based on single photon and its imaging method

Abstract

The present invention relates to the field of detector imaging technology, and in particular to a high-performance ultraviolet imaging detector based on single photons and an imaging method thereof, wherein the imaging method comprises S1: after the incident spectrum is collimated, it is uniformly incident and covered with a digital micromirror device; S2: according to the equivalent mapping relationship between the digital micromirror device and the area array single photon counter, the micromirror array of the digital micromirror device is flipped, so that the incident spectrum is reflected into the same equivalent pixel of the area array single photon counter to obtain a spectral signal. The present invention not only retains the high sensitivity detection capability of the position-sensitive anode area array single photon counter for the ultraviolet band, but also makes up for the problem of poor spatial resolution of the position-sensitive anode area array single photon counter due to the large equivalent pixel, thereby effectively improving the detection resolution capability.

Description

Technical Field

[0001] The invention belongs to the technical field of detector imaging, and in particular relates to a single-photon-based high-performance ultraviolet imaging detector and an imaging method thereof. Background Art

[0002] my country is a major country in the application of atomic fluorescence spectroscopy (AFS). AFS instruments have become important routine detection instruments and are widely used in environmental testing, food hygiene, water quality monitoring and other fields. Instrument products based on hydride generation-atomic fluorescence spectroscopy (HG-AFS) can effectively detect and analyze 12 inorganic metal elements such as arsenic (As), antimony (Sb), bismuth (Bi), and mercury (Hg), and have the advantages of low matrix interference and high sensitivity.

[0003] The imaging system of existing AFS instruments usually uses detectors and spatial light modulators for imaging. Semiconductor detectors such as CMOS or CCD have low sensitivity to ultraviolet detection, especially in the solar-blind band and deep ultraviolet band. Although the spatial resolution is high, the detection sensitivity is poor and it is insensitive to weak signals, which is not suitable for atomic fluorescence detection technology. The equivalent pixel size of the position-sensitive anode array single photon counter is large, which reduces the spatial resolution of the imaging system.

[0004] In addition, the methods of modulating and mapping signals at different pixel positions through spatial light modulators mainly include liquid crystal and LCOS, but the transmittance of liquid crystal and LCOS materials in the ultraviolet band is limited. The surface of the digital micromirror device is mainly made of aluminum material, which can effectively improve the transmittance of ultraviolet spectrum signals. At present, the technology based on digital micromirror devices and photomultiplier tubes has been applied in the field of atomic fluorescence analysis. However, the biggest problem with this method is that the photomultiplier tube does not have imaging capabilities and can only detect the intensity of ultraviolet spectrum signals. Summary of the invention

[0005] In view of this, the present invention aims to provide a high-performance ultraviolet imaging detector based on single photons and an imaging method thereof, so as to solve the technical problem of low detection sensitivity of AFS instruments in the ultraviolet band in the prior art.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows:

[0007] A high-performance ultraviolet imaging detector based on single photons includes a digital micromirror device and an array single photon counter. The equivalent mapping relationship between the digital micromirror device and the array single photon counter is:

[0008] ;

[0009] in, is the coordinate of the equivalent pixel of the area array single photon counter, is the coordinate of the micromirror array of the digital micromirror device, and m is the multiple of the equivalent pixel size of the area array single photon counter and the size of the digital micromirror device.

[0010] Furthermore, the single-photon-based high-performance ultraviolet imaging detector also includes a reflector group arranged between the digital micromirror device and the area array single-photon counter.

[0011] Furthermore, the reflector assembly includes at least one reflector.

[0012] Furthermore, the reflector group includes three reflectors, forming an off-axis three-mirror optical system.

[0013] An imaging method using the above-mentioned high-performance ultraviolet imaging detector based on single photons comprises the following steps:

[0014] S1: The test spectrum is collimated and evenly incident on the micromirror array of the digital micromirror device;

[0015] S2: flip each micromirror in turn according to the planned path, so that each micromirror reflects the test spectrum incident on itself to the area array single photon counter, and obtain the equivalent mapping relationship between the micromirror array of the digital micromirror device and different equivalent pixels of the area array single photon counter;

[0016] S3: The incident spectrum is collimated and evenly incident on the micromirror array of the digital micromirror device;

[0017] S4: Select an equivalent pixel of the area array single photon counter, and according to the equivalent mapping relationship between the micromirror array of the digital micromirror device and different equivalent pixels of the area array single photon counter, flip the micromirror in the micromirror array corresponding to the equivalent pixel, so that the incident spectrum is reflected into the equivalent pixel to obtain a spectral signal.

[0018] Compared with the prior art, the invention can achieve the following beneficial effects:

[0019] Combining the area array single photon counter with the digital micromirror device not only retains the high sensitivity detection capability of the area array single photon counter in the ultraviolet band, but also makes up for the poor spatial resolution of the area array single photon counter due to the large equivalent pixel, thereby effectively improving the detection resolution capability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0021] Figure 1 A schematic diagram of the structure of a high-performance single-photon ultraviolet imaging detector according to an embodiment of the present invention;

[0022] Figure 2 A schematic flow chart of an imaging method implemented by a single-photon high-performance ultraviolet imaging detector according to an embodiment of the present invention;

[0023] Figure 3 A schematic diagram of the flipping sequence of a micromirror array according to an embodiment of the present invention;

[0024] Figure 4 A schematic diagram of the mapping relationship between the micromirror array of the digital micromirror device of the embodiment of the present invention and the equivalent pixel of the area array single photon counter;

[0025] Figure 5 A schematic diagram of the flipping state of a micromirror array according to an embodiment of the present invention.

[0026] Description of reference numerals:

[0027] Digital micromirror device 1, area array single photon counter 2, incident spectrum 3, reflecting mirror group 4. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0029] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0031] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0032] The following will refer to the attached Figure 1 -Attached Figure 5 The invention is described in detail with reference to the embodiments.

[0033] like Figure 1 As shown, the high-performance ultraviolet imaging detector based on single photons provided by an embodiment of the present invention includes a digital micromirror device 1 and an array single photon counter 2. The collimated incident spectrum 3 is incident on the digital micromirror device 1, and then reflected by the digital micromirror device 1 to the array single photon counter 2 for imaging.

[0034] In a specific embodiment of the present invention, a reflector group 4 is further provided between the digital micromirror device 1 and the area array single photon counter 2. The reflector group 4 includes at least one reflector. Figure 1 In the figure, three reflectors are taken as an example to illustrate that the three reflectors constitute an off-axis three-mirror optical system.

[0035] There is an equivalent mapping relationship between the digital micromirror device 1 and the area array single photon counter 2, and the equivalent mapping relationship specifically refers to the mapping relationship between the micromirror array of the digital micromirror device 1 and the equivalent pixel of the area array single photon counter 2. Since the equivalent pixel of the area array single photon counter 2 is larger in size and lower in resolution, while the micromirror array is smaller in size and higher in resolution, the micromirror array of the digital micromirror device 1 corresponds to an equivalent pixel of the area array single photon counter 2 to improve the resolution of the area array single photon counter 2. Of course, the present invention can also divide the micromirror array into multiple micromirror arrays, each micromirror array corresponds to an equivalent pixel of the area array single photon counter 2, that is, multiple micromirror arrays correspond to different equivalent pixels of the area array single photon counter 2, so as to reflect the incident spectra of different micromirror arrays to different equivalent pixels of the area array single photon counter 2.

[0036] The above content describes in detail the high-performance ultraviolet imaging detector based on single photons provided by the present invention. Corresponding to the high-performance ultraviolet imaging detector, the present invention also provides an imaging method implemented by using the high-performance ultraviolet imaging detector based on single photons, such as Figure 2 As shown, the specific steps include:

[0037] S1: The test spectrum is collimated and evenly incident on the micromirror array of the digital micromirror device.

[0038] Taking an N*N micromirror array as an example, the test spectrum is spread over N*N micromirrors.

[0039] S2: Flip each micromirror in turn according to the planned path, so that each micromirror reflects the test spectrum incident on itself to the area array single photon counter, and obtain the equivalent mapping relationship between the micromirror array of the digital micromirror device and different equivalent pixels of the area array single photon counter.

[0040] The area array single photon counter is a detector without actual pixels. It inverts the position of the photon signal of the microchannel plate through the position-sensitive anode to achieve imaging detection of the object.

[0041] The area array single photon counter can be divided into multiple equivalent pixels. The multiple equivalent pixels are divided according to the positional relationship of the spectral signals collected on the area array single photon counter, that is, each equivalent pixel is distinguished by the coordinates of the equivalent pixel.

[0042] Equivalent pixel coordinates (X t0 Y t0 ) is calculated as follows:

[0043] ;

[0044] ;

[0045] In the formula, C represents the capacitance per unit area of ​​the microchannel plate, k represents the inter-electrode modulation coefficient, L represents the diameter of the microchannel plate, I and V represent the current and voltage respectively. and Respectively represent the electron cloud coordinate deviation values ​​in the x-direction and y-direction, and represents the charge coefficient.

[0046] You can follow Figure 3 The planning path in the algorithm flips each micromirror in turn and reflects the test spectrum to different equivalent pixels of the area array single photon counter, so as to obtain the mapping relationship between each micromirror and the equivalent pixel.

[0047] The equivalent mapping relationship between the digital micromirror device and the area array single photon counter is:

[0048] ;

[0049] in, is the coordinate of the equivalent pixel of the single-photon counter, X t is the horizontal coordinate of the equivalent pixel of the area array single photon counter, Y t is the ordinate of the equivalent pixel of the area array single photon counter, is the coordinate of the micromirror array of the digital micromirror device, X k is the horizontal coordinate of the micromirror array of the digital micromirror device, Y k is the ordinate of the micromirror array of the digital micromirror device, and m is the multiple of the equivalent pixel size of the area array single photon counter and the size of the digital micromirror device.

[0050] Of course, the planned path of the present invention can also be a vertical serpentine path or a U-shaped path to achieve the flipping of each micromirror.

[0051] S3: The incident spectrum is collimated and evenly incident on the micromirror array of the digital micromirror device.

[0052] S4: Select an equivalent pixel of the area array single photon counter, and according to the equivalent mapping relationship between the micromirror array of the digital micromirror device and different equivalent pixels of the area array single photon counter, flip the micromirror in the micromirror array corresponding to the equivalent pixel, so that the incident spectrum is reflected into the equivalent pixel to obtain a spectral signal.

[0053] The following takes the mapping of an N*N micromirror array to an equivalent pixel of a planar array single photon counter as an example for explanation.

[0054] like Figure 4 As shown, N*N micromirrors correspond to the same equivalent pixel of the area array single photon counter.

[0055] like Figure 5 As shown, according to the equivalent mapping relationship between the micromirror array of the digital micromirror device and different equivalent pixels of the area array single photon counter, when each micromirror is controlled to flip, a spectral signal will be obtained in the same equivalent pixel. Specifically, according to the positional relationship between the equivalent pixel of the area array single photon counter and each micromirror, the micromirrors with coordinates (1, 1) to (N, N) are flipped in sequence one by one, and each flipping takes T0 time.

[0056] Each time the digital micromirror device flips to an equivalent pixel, it will be locked within T0 and will no longer flip at will. During T0, the spectral signal received at the equivalent pixel position (m, m) of the array single photon counter is integrated to obtain the spectral signal intensity values ​​of N micromirrors within T0.

[0057] By distributing the spectral data of all N micromirrors on equivalent pixels, the accumulated spectral signals of N micromirrors can be obtained under the condition of one equivalent pixel.

[0058] If the N*N micromirror array is divided into M micromirror arrays, and the M micromirror arrays correspond to the M equivalent pixels of the area array single-photon counter, the micromirrors of the first micromirror array can be controlled to flip and map the incident spectrum to the first equivalent pixel of the area array single-photon counter. The mapping of other micromirror arrays and corresponding equivalent pixels can be understood in the same way.

[0059] Since the micromirror has only two reflection angles (+12 degrees or -12 degrees), the micromirror does not work when it is not flipped; when the micromirror is flipped to +12 degrees, the incident spectrum is reflected to the area array single photon counter, and when the micromirror is flipped to -12 degrees, the incident spectrum is reflected out of the area array single photon counter.

[0060] By controlling the flipping of the micromirrors, the micromirror array that needs to form an image is flipped to +12 degrees, and the micromirror array that does not need to form an image is flipped to -12 degrees, thereby ensuring that the incident spectrum is incident on the same equivalent pixel.

[0061] It should be understood that the various forms of processes shown above can be used to reorder, add or delete steps. For example, the steps described in the disclosure of the present invention can be performed in parallel, sequentially or in different orders, as long as the desired results of the technical solution disclosed in the present invention can be achieved, and this document does not limit this.

[0062] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-performance ultraviolet imaging detector based on single photons, characterized in that: Including a digital micromirror device and an area array single photon counter, the equivalent mapping relationship between the micromirror array of the digital micromirror device and different equivalent pixels of the area array single photon counter is: ； in, is the coordinate of the equivalent pixel of the area array single photon counter, X t is the horizontal coordinate of the equivalent pixel of the area array single photon counter, Y t is the ordinate of the equivalent pixel of the area array single photon counter, is the coordinate of the micromirror array of the digital micromirror device, X k is the horizontal coordinate of the micromirror array of the digital micromirror device, Y k is the ordinate of the micromirror array of the digital micromirror device, and m is the multiple of the equivalent pixel size of the area array single photon counter and the size of the digital micromirror device; Equivalent pixel coordinates (X t Y t ) is calculated as follows: ； ； In the formula, C represents the capacitance per unit area of ​​the microchannel plate, k represents the inter-electrode modulation coefficient, L represents the diameter of the microchannel plate, I and V represent the current and voltage respectively. and Respectively represent the electron cloud coordinate deviation values ​​in the x-direction and y-direction, and represents the charge coefficient.

2. The high-performance single-photon ultraviolet imaging detector according to claim 1, characterized in that: It also includes a reflector group arranged between the digital micromirror device and the area array single photon counter.

3. The high-performance single-photon ultraviolet imaging detector according to claim 2, characterized in that: The reflector assembly includes at least one reflector.

4. The high-performance single-photon-based ultraviolet imaging detector according to claim 3, characterized in that: The reflector group includes three reflectors, forming an off-axis three-mirror optical system.

5. An imaging method using the high-performance single-photon ultraviolet imaging detector according to any one of claims 1 to 4, characterized in that: The steps include: S1: The test spectrum is collimated and evenly incident on the micromirror array of the digital micromirror device; S2: flip each micromirror in turn according to the planned path, so that each micromirror reflects the test spectrum incident on itself to the area array single photon counter, and obtain the equivalent mapping relationship between the micromirror array of the digital micromirror device and different equivalent pixels of the area array single photon counter; S3: The incident spectrum is collimated and evenly incident on the micromirror array of the digital micromirror device; S4: Select an equivalent pixel of the area array single photon counter, and according to the equivalent mapping relationship between the micromirror array of the digital micromirror device and different equivalent pixels of the area array single photon counter, flip the micromirror in the micromirror array corresponding to the equivalent pixel, so that the incident spectrum is reflected into the equivalent pixel to obtain a spectral signal.

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