Rectangular view field design method for ultraviolet non-line-of-sight communication receiving end and application of rectangular view field design method

Abstract

The invention provides a rectangular field-of-view design method for an ultraviolet non-line-of-sight communication receiving end and application thereof, and belongs to the technical field of wireless optical communication, the method comprises the following steps: pre-determining the center distance length of a light shield and the upper field-of-view angle, the lower field-of-view angle, the left field-of-view angle and the right field-of-view angle of a rectangular receiving field-of-view; based on the center distance length, the upper view field angle, the lower view field angle, the left view field angle, the right view field angle and the width and length of the rectangular light sensing surface, calculating structural parameters of a light shield used for generating the rectangular receiving view field; wherein the structural parameters comprise the upper and lower edge lengths, the left and right edge lengths and the position of a vertical center point of a larger rectangular opening of the light shield. Through the design of the rectangular view field and the accurate matching of the rectangular light-sensitive surface, the photon receiving efficiency is remarkably improved, stray light and electromagnetic interference are effectively inhibited, and thus the signal-to-noise ratio of weak light signal detection and the system sensitivity are improved.

Description

Technical Field

[0001] This invention relates to the field of wireless optical communication technology, and in particular to a rectangular field-of-view design method for an ultraviolet non-line-of-sight communication receiver and its application. Background Technology

[0002] Non-line-of-sight ultraviolet (NOS) communication boasts advantages such as strong anti-interference capabilities, good concealment, and flexible deployment. In low-light signal detection scenarios (NOS), photomultiplier tubes (PMTs) are required to achieve high-sensitivity detection. PMTs are mainly divided into end-window and side-window types. For ultraviolet band detection, Hamamatsu's R7154 (side-window, 8×24mm rectangular photosensitive surface) and R795 (end-window) are typical examples. A comparison shows that side-window PMTs are more suitable for NOS low-light communication scenarios, with their core advantage being higher gain (R7154 typically achieves a gain of 10). 7 Far exceeding R795's 1.4×10 4 It can efficiently amplify weak light signals. Its cathode area is larger (192mm²) and it is equipped with a multi-stage louvered multiplier. Its photon collection efficiency is significantly better than that of the small focusing cathode (7-19.6mm²) with end window type. At the same time, the side window structure facilitates the alignment and integration of the optical system and can better adapt to the large spot weak light signal converged by the lens group.

[0003] However, existing receiving devices generally use conical light shields, which are used to limit the receiving field of view, reduce stray light interference (sunlight background noise), and assist in electromagnetic shielding. Although this structure is compatible with the circular photosensitive surface of the end-window type PMT, it is seriously mismatched with the rectangular photosensitive surface of the side-window type PMT. This not only allows a large amount of ambient stray light, non-target wavelength light, and electromagnetic interference to enter the device, superimposed with dark current noise, reducing the accuracy of weak light detection, but also, due to the misalignment between the field of view shape and the photosensitive surface, places higher demands on the alignment in the direction perpendicular to the long side of the photosensitive surface, increasing the complexity of system deployment and debugging. Summary of the Invention

[0004] This invention provides a rectangular field-of-view design method for ultraviolet non-line-of-sight communication receivers and its application, in order to overcome the deficiencies in the prior art.

[0005] In a first aspect, the present invention provides a receiving device for ultraviolet non-line-of-sight communication, comprising: a light shield, a filter and a side-window type photomultiplier tube arranged along the optical path direction, and an electromagnetic shielding structure; The light shield is rectangular and horn-shaped with a rectangular channel, which, together with the side-window photomultiplier tube, generates a rectangular receiving field of view; wherein, the end of the rectangular channel closer to the side-window photomultiplier tube forms a smaller rectangular opening, and the end farther from the side-window photomultiplier tube forms a larger rectangular opening, and the planes containing the two rectangular openings are parallel. The filter is used to filter the wavelength of the light signal passing through the light shield to filter out the ultraviolet light signal; An electromagnetic shielding structure is provided to provide electromagnetic shielding for the side-window type photomultiplier tube. The side-window type photomultiplier tube uses a rectangular photosensitive surface to convert the filtered ultraviolet light signal into an electrical signal.

[0006] The receiving device for ultraviolet non-line-of-sight communication provided by the present invention integrates the filter and electromagnetic shielding structure with the light shield into a single structure.

[0007] According to the receiving apparatus for ultraviolet non-line-of-sight communication provided by the present invention, the rectangular receiving field of view is an asymmetric rectangular field of view.

[0008] According to the receiving apparatus for ultraviolet non-line-of-sight communication provided by the present invention, the asymmetric rectangular field of view is configured such that the upper and lower field of view angles are greater than the left and right field of view angles, thereby enhancing the signal reception capability in scenarios with lateral obstacles.

[0009] According to the receiving device for ultraviolet non-line-of-sight communication provided by the present invention, the asymmetric rectangular field of view is configured such that the left and right field of view angles are greater than the upper and lower field of view angles, thereby enhancing the signal reception capability in scenarios with longitudinal obstacles.

[0010] Secondly, the present invention also provides a rectangular field-of-view design method applicable to any of the above-mentioned receiving devices, comprising: Predetermine the center distance length of the sunshade, as well as the upper, lower, left, and right field of view angles of the rectangular receiving field of view; Based on the center distance length, the upper field of view angle, the lower field of view angle, the left field of view angle, and the right field of view angle, as well as the width and length of the rectangular photosensitive surface, the structural parameters of the light shield used to generate the rectangular receiving field of view are calculated; wherein, the center distance length is the vertical distance between the two rectangular openings; The structural parameters include the lengths of the top and bottom sides and the left and right sides of the larger rectangular opening of the light shield, as well as the position of the vertical center point; the straight line passing through the center point and the vertical center point of the smaller rectangular opening is perpendicular to the plane containing the rectangular opening.

[0011] According to the rectangular field-of-view design method for the receiving device provided by the present invention, when the rectangular receiving field of view is asymmetrically designed, the calculation formulas for the lengths l1 of the top and bottom sides and l2 of the left and right sides are as follows: l1 = d × (tan(θ) left ) + tan(θ right )) – x; l2 = d × (tan(θ) up) + tan(θ down )) – y; The position of the offset vertical center point is determined by |OM| and |HN|, and the formulas for calculating |OM| and |HN| are as follows: |OM| = |OC|-|CM|=d × tan(θ left ) - x / 2-l1 / 2; |HN| = |GH|-|GN|=d × tan(θ up ) - y / 2-l2 / 2; Where d is the center distance length, θ up θ down θ left θ right These are the upper field of view, lower field of view, left field of view, and right field of view, respectively. x and y are the width and length of the rectangular photosensitive surface, respectively. Points M and N are the midpoints of the line segments l1 and l2, respectively. |OM| represents the rightward offset distance of the vertical center point relative to the center point of the larger rectangular opening, and |HN| represents the downward offset distance of the vertical center point relative to the center point of the larger rectangular opening.

[0012] According to the rectangular field-of-view design method of the receiving device provided by the present invention, when the rectangular receiving field of view is a symmetrical field of view, the symmetrical field of view angle is set to θ, and the vertical center point coincides with the center point of the larger rectangular opening; The formulas for calculating the lengths of the top and bottom sides (l1) and the left and right sides (l2) are as follows: l1 = 2d × tan(θ / 2) – x; l2 = 2d × tan(θ / 2) – y; Where d is the center distance length, and x and y are the width and length of the rectangular photosensitive surface, respectively.

[0013] Thirdly, the present invention provides a non-line-of-sight ultraviolet light communication method, which uses any of the receiving devices described above to detect and receive ultraviolet light signals.

[0014] The non-line-of-sight ultraviolet communication method provided by the present invention further includes: adjusting the upper, lower, left, and right field-of-sight angles of the rectangular receiving field of view of the receiving device to adapt to different application scenarios.

[0015] The rectangular field-of-view design method for ultraviolet non-line-of-sight communication receivers and its application provided by this invention have the following advantages compared with the prior art: (1) A rectangular horn shield is designed to generate a rectangular receiving field of view, which can be fully adapted to the rectangular cathode photosensitive surface of the side window type PMT, reduce the influence of stray light, reduce electromagnetic interference, improve the detection capability of weak ultraviolet light signals, and can be applied to non-line-of-sight ultraviolet light communication scenarios.

[0016] (2) A rectangular receiving field of view design and light shield implementation scheme is provided, which can be used to adapt the original light shield of the side window PMT, and also provides an integrated implementation scheme of rectangular speaker light shield + shielding cover + filter.

[0017] (3) An asymmetric rectangular receiving field of view with independently defined vertical and horizontal field of view angles was designed. It can be applied to the elimination of solar background noise interference, as well as to the link enhancement and protection in the presence of different types of obstacles. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of an application scenario for the non-line-of-sight ultraviolet communication system provided in this embodiment of the invention; Figure 2 This is a schematic diagram of the signal processing flow of the ultraviolet non-line-of-sight communication system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram comparing the spatial shapes of a rectangular receiving field of view and a conical receiving field of view provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the geometric relationship projection and parameter design of the asymmetric rectangular receiving field of view provided in an embodiment of the present invention; Figure 5 This is a schematic diagram comparing the design effects of a rectangular receiving field of view and a conical receiving field of view provided by the present invention; Figure 6 This is a schematic diagram illustrating a typical application of the asymmetric rectangular field of view provided by the present invention; Figure 7 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] It should be noted that, in the description of the embodiments of the present invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0022] The terms "first," "second," etc., used in this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more.

[0023] The following is combined Figures 1-7 This invention describes the rectangular field-of-view design method for ultraviolet non-line-of-sight communication receivers and its applications, provided by embodiments of the present invention.

[0024] Figure 1 This is a schematic diagram of an application scenario for the non-line-of-sight ultraviolet communication system provided in this embodiment of the invention, such as... Figure 1 As shown, in non-line-of-sight ultraviolet communication, the transmitter and receiver transmit signals via a non-line-of-sight link, relying on atmospheric scattering of ultraviolet photons. Under normal circumstances, they are aligned horizontally, and the communication performance is adjusted by adjusting the transmitter elevation angle, beam angle, receiver elevation angle, and field of view (FOV). Figure 2 This is a schematic diagram of the signal processing flow of the ultraviolet non-line-of-sight communication system provided in an embodiment of the present invention, as shown below. Figure 2 As shown, the data from the transmitting end is processed and then modulated into the driving circuit module, causing the ultraviolet light source (LED) to emit ultraviolet light signals. After the photons are scattered and transmitted through the atmosphere, the receiving end converts the light signals into electrical signals through a structure with a photomultiplier tube (PMT) as the core. After processing, the signals are output for display. The power supplies are respectively for the driving circuit and signal processing module of the transmitting end and the high voltage module and signal processing module of the receiving end.

[0025] The core component of the system is the weak ultraviolet photon detection stage (i.e., the receiver), whose core objective is to accurately capture weak ultraviolet light signals from complex interference and complete photoelectric conversion.

[0026] The receiving device for ultraviolet non-line-of-sight communication provided by the present invention can be used for weak ultraviolet photon detection, including: a light shield, a filter and a side window type photomultiplier tube arranged along the optical path direction, and an electromagnetic shielding structure; The light shield is rectangular and horn-shaped with a rectangular channel, which, together with the side-window photomultiplier tube, generates a rectangular receiving field of view; wherein, the end of the rectangular channel closer to the side-window photomultiplier tube forms a smaller rectangular opening, and the end farther from the side-window photomultiplier tube forms a larger rectangular opening, and the planes containing the two rectangular openings are parallel. The filter is used to filter the wavelength of the light signal passing through the light shield to filter out the ultraviolet light signal; An electromagnetic shielding structure is provided to provide electromagnetic shielding for the side-window type photomultiplier tube. The side-window type photomultiplier tube uses a rectangular photosensitive surface to convert the filtered ultraviolet light signal into an electrical signal.

[0027] Optionally, the filter and electromagnetic shielding structure are integrated with the light shield into a single structure.

[0028] See Figure 2 The core part of the system relates to the technical content of the receiving device for ultraviolet non-line-of-sight communication provided by this invention, such as... Figure 2 As shown, ultraviolet photons (optical signals) first enter the light shield, where physical blocking (limiting the field of view) filters stray light from the environment, reducing interference from irrelevant light to subsequent detection at the source. The optical signal passing through the light shield then passes through a filter, which uses optical filtering characteristics to precisely intercept specific wavelengths and eliminate interference from other bands, ensuring the targeting and accuracy of the detection. The filtered ultraviolet light then enters the electromagnetic shielding box, where external electromagnetic radiation is isolated, avoiding dark current fluctuations and gain reduction caused by external electromagnetic fields. The ultraviolet photons finally reach the core device, the photomultiplier tube (PMT): its internal cathode photosensitive surface (photocathode) is excited by ultraviolet photon impacts to generate electrons. After multi-stage amplification, a large number of these electrons are collected by the anode, forming an electrical signal that can be directly processed and displayed, completing the efficient conversion of weak light signals into electrical signals.

[0029] The receiving field of view is the spatial range (field of view angle) within which the receiver effectively captures optical signals. Figure 3 This is a schematic diagram comparing the spatial shapes of a rectangular receiving field of view and a conical receiving field of view provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the conical receiving field of view is conical in shape and is generated by the end window PMT in conjunction with a circular horn-shaped light shield, which can capture the ultraviolet light signal inside the cone; the rectangular receiving field of view is a rectangular area and is generated by the side window PMT in conjunction with a light shield component with a rectangular channel, which is used to receive the light signal within the rectangular area.

[0030] Figure 4This is a schematic diagram of the geometric relationship projection and parameter design of the asymmetric rectangular receiving field of view provided in an embodiment of the present invention, as shown below. Figure 4 As shown, designing a rectangular receiving space field of view involves determining the required vertical, horizontal, and vertical field of view angles for the receiver, and then determining the parameters of the horn-shaped light shield based on these angles to ensure that the required rectangular field of view can be generated.

[0031] The present invention provides a rectangular field-of-view design method for the aforementioned receiving device, comprising: pre-determining the center distance length of the light shield, and the upper field-of-view angle, lower field-of-view angle, left field-of-view angle, and right field-of-view angle of the rectangular receiving field of view; calculating the structural parameters of the light shield used to generate the rectangular receiving field of view based on the center distance length, the upper field-of-view angle, the lower field-of-view angle, the left field-of-view angle, and the right field-of-view angle, as well as the width and length of the rectangular photosensitive surface; wherein the structural parameters include the upper and lower side lengths and the left and right side lengths of the larger rectangular opening of the light shield, and the position of the vertical center point.

[0032] Specifically, refer to Figure 4 The parameters are defined as follows: These represent the field of view angles, respectively, up, down, left, and right. The center point of the smaller rectangular opening, through Draw perpendicular lines to the plane containing the larger rectangular opening; the intersection point is the vertical center point. O The center distance of the light shield is Understandably, the center-to-center distance is the vertical distance between the planes containing the two rectangular openings of the light shield. These represent the width and length of the PMT cathode photosensitive surface, respectively. If the smaller rectangular opening of the rectangular channel of the light shield matches the size of the rectangular photosensitive surface of the side-window photomultiplier tube, then only the upper and lower side lengths of the larger rectangular opening need to be determined. left and right side lengths and vertical center point The location.

[0033] Specifically, the lengths of the top and bottom edges The influence of the left and right field of view angles can be expressed by the formula:

[0034] Similarly, the lengths of the left and right sides The influence of the upper and lower field of view angles can be expressed by the formula:

[0035] Offset vertical center point The location can be determined by Combination The only certainty is that its calculation formula is as follows:

[0036] Among them, point M , N They are respectively l 1, l The midpoint of line segment 2, |OM| represents the distance to the right of the vertical center point relative to the center point of the larger rectangular opening of the sunshade, and |HN| represents the distance to the down of the vertical center point relative to the center point of the larger rectangular opening of the sunshade.

[0037] The above is an asymmetrical design based on the inconsistent directions of the four field of view angles (up, down, left, and right). It assumes that the field of view angles are symmetrical, meaning the field of view angles are... At this time, the vertical center point At this point, no offset is needed; the view is located at the center of the rectangular field of view, and only the side length needs to be determined. The simplified formula is as follows: .

[0038] Taking Hamamatsu PMT-R7154 as an example, its cathode photosensitive area is The center distance of the horn-shaped light shield is set to Depending on the required field of view, they can be divided into the following three categories: (1) The receiving field of view is asymmetrical in all directions: Left field of view of the receiver Right field of view upper field of view Lower field of view Then the upper and lower side lengths of the larger rectangular face (i.e., the larger rectangular opening) facing outwards of the light shield are... The vertical center point is offset to the right by 41.185 mm compared to the center of the larger rectangular surface of the sunshade. (Left and right side lengths) The vertical center point is offset 15.475mm below the center of the larger rectangular surface of the sunshade.

[0039] (2) The receiving field of view is symmetrical vertically and horizontally: The vertical field of view requirement is greater, and the horizontal field of view of the receiver is also greater. Upper and lower field of view Then the top and bottom side lengths of the largest rectangular face facing outwards of the light shield are... left and right side lengths The position of the vertical center point coincides with the center of the outer rectangular surface of the light shield.

[0040] (3) The receiving field of view needs to be symmetrical in all directions: Field of view That is, the top and bottom side lengths of the largest rectangular surface facing outwards of the light shield. left and right side lengths The position of the vertical center point coincides with the center of the outer rectangular surface of the light shield.

[0041] Therefore, a light shield device can be designed to meet the specific requirements. The material can be metal according to the electromagnetic shielding requirements, and the specific material and thickness should be determined according to the specific requirements of electromagnetic shielding.

[0042] Figure 5 This is a schematic diagram comparing the design effects of a rectangular receiving field of view and a conical receiving field of view provided by the present invention, as shown in the figure. Figure 5 As shown, this invention designs a rectangular horn light shield to generate a rectangular receiving field of view, which can be fully adapted to the rectangular cathode photosensitive surface of a side-window PMT, reducing stray light influence, reducing electromagnetic interference, and improving the detection capability of weak ultraviolet light signals. It is applicable to non-line-of-sight ultraviolet light communication scenarios. This invention provides a rectangular receiving field of view design and light shield implementation scheme, which can be used to adapt to the original light shield of a side-window PMT, and also provides an integrated implementation scheme of rectangular horn light shield + shielding cover + filter.

[0043] Furthermore, this invention designs an asymmetric rectangular receiving field of view whose vertical, horizontal, and vertical field of view angles can be freely defined independently. This can be applied to suppressing solar background noise interference, as well as to link enhancement and protection in the presence of different types of obstacles.

[0044] Figure 6 This is a typical application diagram of the asymmetric rectangular field of view provided by the present invention, such as... Figure 6 As shown, the asymmetric rectangular field of view can be configured such that the upper and lower field of view angles are greater than the left and right field of view angles, in order to enhance signal reception capability in scenarios with lateral obstacles; the asymmetric rectangular field of view can also be configured such that the left and right field of view angles are greater than the upper and lower field of view angles, in order to enhance signal reception capability in scenarios with longitudinal obstacles.

[0045] Figure 7 This is a schematic diagram of the structure of the electronic device provided by the present invention, such as... Figure 7As shown, the electronic device may include a processor 710, a communications interface 720, a memory 730, and a communication bus 740, wherein the processor 710, communications interface 720, and memory 730 communicate with each other via the communication bus 740. The processor 710 can call logical instructions in the memory 730 to execute a rectangular field-of-view design method for the receiving device. This method includes: pre-determining the center distance length of the light shield, and the upper, lower, left, and right field-of-view angles of the rectangular receiving field of view; calculating the structural parameters of the light shield used to generate the rectangular receiving field of view based on the center distance length, the upper, lower, left, and right field-of-view angles, and the width and length of the rectangular photosensitive surface; wherein the structural parameters include the upper and lower side lengths and left and right side lengths of the larger rectangular opening of the light shield, and the position of the vertical center point.

[0046] On the other hand, the present invention also provides a computer program product, the computer program product including a computer program stored on a non-transitory computer-readable storage medium, the computer program including program instructions, when the program instructions are executed by a computer, the computer is able to execute the rectangular field-of-view design method of the receiving device provided in the above embodiments, the method including: pre-determining the center distance length of the light shield, and the upper field-of-view angle, lower field-of-view angle, left field-of-view angle and right field-of-view angle of the rectangular receiving field of view; calculating the structural parameters of the light shield for generating the rectangular receiving field of view based on the center distance length, the upper field-of-view angle, the lower field-of-view angle, the left field-of-view angle and the right field-of-view angle, and the width and length of the rectangular photosensitive surface; wherein, the structural parameters include the upper and lower side lengths and the left and right side lengths of the larger rectangular opening of the light shield and the position of the vertical center point.

[0047] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements a rectangular field-of-view design method for the receiving device provided in the above embodiments. The method includes: pre-determining the center distance length of a light shield, and the upper field-of-view angle, lower field-of-view angle, left field-of-view angle, and right field-of-view angle of the rectangular receiving field of view; calculating structural parameters of the light shield for generating the rectangular receiving field of view based on the center distance length, the upper field-of-view angle, the lower field-of-view angle, the left field-of-view angle, and the right field-of-view angle, as well as the width and length of the rectangular photosensitive surface; wherein the structural parameters include the upper and lower side lengths and the left and right side lengths of the larger rectangular opening of the light shield, and the position of the vertical center point.

[0048] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A receiving device for ultraviolet non-line-of-sight communication, characterized in that, include: A light shield, a filter, and a side-window type photomultiplier tube arranged along the optical path, as well as an electromagnetic shielding structure; The light shield is rectangular and horn-shaped with a rectangular channel, which, together with the side-window photomultiplier tube, generates a rectangular receiving field of view; wherein, the end of the rectangular channel closer to the side-window photomultiplier tube forms a smaller rectangular opening, and the end farther from the side-window photomultiplier tube forms a larger rectangular opening, and the planes containing the two rectangular openings are parallel. The filter is used to filter the wavelength of the light signal passing through the light shield to filter out the ultraviolet light signal; An electromagnetic shielding structure is provided to provide electromagnetic shielding for the side-window type photomultiplier tube. The side-window type photomultiplier tube uses a rectangular photosensitive surface to convert the filtered ultraviolet light signal into an electrical signal.

2. The receiving device according to claim 1, characterized in that, The filter and electromagnetic shielding structure are integrated with the light shield into a single unit.

3. The receiving device according to claim 1, characterized in that, The rectangular receiving field of view is an asymmetric rectangular field of view.

4. The receiving device according to claim 3, characterized in that, The asymmetric rectangular field of view is configured such that the upper and lower field of view angles are greater than the left and right field of view angles, in order to enhance signal reception capability in scenarios with lateral obstacles.

5. The receiving device according to claim 3, characterized in that, The asymmetric rectangular field of view is configured such that the left and right field of view angles are greater than the upper and lower field of view angles, in order to enhance signal reception capability in scenarios with longitudinal obstacles.

6. A method for designing a rectangular field of view for a receiving device as described in any one of claims 1 to 5, characterized in that, include: The center distance of the light shield, as well as the upper, lower, left, and right field of view of the rectangular receiving field of view, are predetermined; wherein, the center distance is the vertical distance between the two rectangular openings. Based on the center distance length, the upper field of view angle, the lower field of view angle, the left field of view angle, and the right field of view angle, as well as the width and length of the rectangular photosensitive surface, calculate the structural parameters of the light shield used to generate the rectangular receiving field of view; The structural parameters include the lengths of the top and bottom sides and the left and right sides of the larger rectangular opening of the light shield, as well as the position of the vertical center point; the straight line passing through the center point and the vertical center point of the smaller rectangular opening is perpendicular to the plane containing the rectangular opening.

7. The rectangular field-of-view design method according to claim 6, characterized in that, When the rectangular receiving field of view is asymmetrically designed, the formulas for calculating the lengths of the top and bottom sides l1 and the left and right sides l2 are as follows: l1= d × (tan(θ left ) + tan(θ right )) – x; l2 = d × (tan(θ up ) + tan(θ down )) – y; The position of the offset vertical center point is determined by |OM| and |HN|, and the formulas for calculating |OM| and |HN| are as follows: |OM| = d × tan(θ left ) - x / 2-l1 / 2; |HN| =d × tan(θ up ) - y / 2-l2 / 2; Where d is the center distance length, θ up θ down θ left θ right These are the upper field of view, lower field of view, left field of view, and right field of view, respectively. x and y are the width and length of the rectangular photosensitive surface, respectively. |OM| represents the rightward offset distance of the vertical center point relative to the center point of the larger rectangular opening, and |HN| represents the downward offset distance of the vertical center point relative to the center point of the larger rectangular opening.

8. The rectangular field-of-view design method according to claim 6, characterized in that, When the rectangular receiving field of view is a symmetrical field of view, the symmetrical field of view angle is set to θ, and the vertical center point coincides with the center point of the larger rectangular opening; The formulas for calculating the lengths of the top and bottom sides (l1) and the left and right sides (l2) are as follows: l1 = 2d × tan(θ / 2) – x; l2 = 2d × tan(θ / 2) – y; Where d is the center distance length, and x and y are the width and length of the rectangular photosensitive surface, respectively.

9. A non-line-of-sight ultraviolet light communication method, characterized in that, The receiving device as described in any one of claims 1 to 5 is used for the detection and reception of ultraviolet light signals.

10. The non-line-of-sight ultraviolet communication method according to claim 9, characterized in that, By adjusting the top, bottom, left, and right field-of-view angles of the rectangular receiving field of view of the receiving device, it can be adapted to different application scenarios.

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