A 3D printing-based long-afterglow material closed synchronous photographing system and method

Abstract

The application provides a long-afterglow material closed synchronous photographing system and method based on 3D printing, which comprises a 3D printing polymer closed cavity, an ultraviolet lamp tube excitation module, a single-chip microcomputer control module, an image acquisition module, a display storage module and a photosensitive resistance light leakage detection alarm module. The application realizes low-cost structure adaptation through the 3D printing cavity, solves the problems of long processing period and fixed structure of the traditional metal dark box, controls the time difference between the closing of the ultraviolet lamp tube and the shooting of the camera module within milliseconds through the single-chip microcomputer, completely eliminates the time error caused by manual operation, integrates the photosensitive detection and the buzzer alarm functions, and can detect the light leakage of the cavity in real time. The application can realize the automatic collection of the afterglow image at a specific time point after the excitation of the long-afterglow material is completed, significantly improves the accuracy, repeatability and experimental efficiency of the afterglow photograph collection, and is suitable for the performance testing and screening of various inorganic, organic and composite long-afterglow materials.

Description

Technical Field

[0001] This invention belongs to the field of luminescent material testing and optical imaging detection technology, specifically relating to a closed synchronous imaging system and method for observing, photographing, and recording the afterglow luminescence of long-afterglow materials. This invention also relates to the application of 3D printed structural design and embedded automatic control technology in luminescent material testing devices. Background Technology

[0002] Long-persistent luminescent materials are functional materials that continue to emit light for a period of time after the external excitation source has ceased. These materials are typically excited by ultraviolet light, visible light, or other energy sources, causing excitons and charge carriers within the material to be captured by defect or trap energy levels. After excitation ceases, they slowly release energy, resulting in a continuous afterglow emission phenomenon. Due to their characteristics of requiring no continuous power supply, long emission duration, and low background interference, long-persistent luminescent materials have been widely used in fields such as security marking, anti-counterfeiting encryption, bioimaging, environmental monitoring, photocatalysis, and functional coatings. In material research and performance screening, afterglow photographs can quickly and intuitively reflect the luminescence intensity, color, spatial uniformity, and decay state of the material after excitation is removed. Therefore, stable and repeatable recording of afterglow photographs of long-persistent materials is of great significance. However, the luminescence intensity of long-persistent materials decays rapidly within a short period after excitation ceases, followed by a slow decay phase at low brightness. Therefore, capturing afterglow photographs requires high standards for ambient light isolation, excitation source selection, shooting time control, and the stability of shooting parameters. If there is light leakage, reflection, or external stray light interference in the shooting environment, it can easily lead to an increase in the brightness of the image background, affecting the accurate recording of weak afterglow signals. If there are differences in the excitation distance, excitation time, or shooting angle of different samples, it will cause a lack of comparability between the photos, affecting the subsequent judgment of material properties.

[0003] Currently, the observation or photography of long-persistent materials mostly employs darkrooms, metal dark boxes, or simple light-shielding boxes in conjunction with a camera. While darkrooms provide a good light-shielding environment, they are costly to construct, require a large area, and are not easily adaptable to different experimental needs. Traditional metal dark boxes have long processing cycles and fixed structures, making it difficult to flexibly adapt to different sample sizes, light sources in different installation positions, and different camera modules. Simple light-shielding boxes, while cheaper, have poor airtightness and structural stability, are prone to light leakage, and cannot meet the repeatability requirements of low-light photography. Existing photography processes commonly suffer from time errors due to manual operation. Researchers typically need to first turn on the excitation light source to illuminate the sample, then manually turn off the light source and quickly take the picture. Because the luminescence intensity of long-persistent materials changes significantly over time after excitation stops, an uncertain time interval inevitably exists between manually turning off the light and pressing the shutter. Especially when comparing multiple samples or repeating experiments, this time interval difference directly affects the brightness and decay state of the image, leading to insufficient consistency between experimental data and image results. While some devices can fix the positions of the light source and camera, they still rely primarily on manual control of the light source's start-up and shutdown, as well as the imaging process, lacking synchronous control between excitation termination and image acquisition. Existing devices typically lack real-time detection and alerting capabilities for light leakage inside the dark chamber. In long-afterglow, low-light imaging scenarios, even slight light leakage can significantly impact imaging results, and researchers often only discover the problem after the image shows anomalies, reducing experimental efficiency. Based on these issues, there is an urgent need for a low-cost, customizable, well-sealed, long-afterglow material sealed imaging system that can automatically control the excitation light source and simultaneously capture images, while also possessing light leakage detection alarms and image display and storage functions, to improve the accuracy, repeatability, and experimental convenience of afterglow image acquisition. Summary of the Invention

[0004] The purpose of this invention is to provide a closed synchronous imaging system and method for long-afterglow materials based on 3D printing. It aims to completely solve the problems of large time error in manual operation, high cost and poor adaptability of traditional devices, and light leakage interference in afterglow imaging of long-afterglow materials by combining a customizable closed cavity printed by 3D printing with microcontroller precise synchronous control technology and real-time light leakage detection function. It achieves low-cost, high-accuracy, and highly repeatable automatic acquisition of afterglow images of long-afterglow materials, providing a reliable experimental device for material performance testing and screening.

[0005] According to one objective of the present invention, the present invention provides a closed synchronous imaging system for long afterglow materials based on 3D printing, comprising: The 3D-printed polymer sealed cavity adopts a pull-out structure design. The top is reserved with a camera lens mounting hole and a pull-out slot, the side is provided with wiring holes and matching sealing caps, and the interior is reserved with installation positions for light sources, sensors and control modules. The ultraviolet lamp excitation module is installed inside a sealed cavity to provide uniform ultraviolet excitation light for long-afterglow materials. The microcontroller control module is electrically connected to the ultraviolet lamp excitation module, image acquisition module, display and storage module, and light leakage detection and alarm module, respectively, and is used to control the timing operation of the entire system. The image acquisition module is installed at the camera lens mounting hole at the top of the sealed cavity and is used to acquire afterglow images of long afterglow materials. The display storage module is electrically connected to the microcontroller control module and is used to display system parameters, provide real-time previews, and store the acquired afterglow images. The light leakage detection alarm module is installed inside a sealed cavity to detect the light intensity inside the cavity in real time. When the light intensity exceeds a preset threshold, an alarm signal is issued.

[0006] Furthermore, the 3D-printed polymer sealed cavity is made of PLA material using 3D printing technology. The opening diameter of the side wiring hole is 50mm, the overall diameter is 60mm, the thickness is 2.5mm, and the groove depth is 200mm.

[0007] Furthermore, the ultraviolet lamp excitation module is an ultraviolet black light lamp with a wavelength of 365nm or 254nm, which is electrically connected to the microcontroller control module through a relay, and its on / off timing is controlled by the microcontroller.

[0008] Furthermore, the microcontroller control module uses an STM32F407VE microcontroller as the main control chip. This chip is based on the ARM Cortex-M4 core, has a main frequency of 168MHz, and is equipped with 512KB Flash and 192+4KB SRAM.

[0009] Furthermore, the image acquisition module adopts an OV7670 CMOS image sensor, supports VGA (640×480) resolution output, and has built-in automatic exposure, automatic white balance and automatic gain control functions. It is connected to the microcontroller control module through an external FIFO memory.

[0010] Furthermore, the display storage module adopts an ILI9341 TFT LCD screen with an integrated XPT2046 resistive touch chip, a resolution of 240×320, and supports 16-bit RGB565 color mode. It is connected to the microcontroller control module via an SPI interface.

[0011] Furthermore, the light leakage detection alarm module includes a photoresistor sensor, an LM393 comparator, a relay, and an active buzzer; the photoresistor sensor collects the light intensity signal inside the cavity, and after processing by the LM393 comparator, it outputs a control signal. When the light intensity exceeds a preset threshold, the relay is activated, driving the active buzzer to emit an alarm sound.

[0012] Furthermore, the light leakage detection alarm module is also equipped with an adjustable potentiometer for adjusting the light intensity detection threshold.

[0013] A closed-loop synchronous imaging method for long afterglow materials based on 3D printing, using the aforementioned system, includes the following steps: S1: Place the long afterglow material sample to be tested on the sample stage inside the sealed cavity, close the cavity cover and seal the side wiring holes. S2: Start the system. The light leakage detection alarm module automatically detects the light intensity inside the cavity. If the light intensity exceeds the preset threshold, the buzzer will sound an alarm to indicate that there is light leakage. If the light intensity is lower than the preset threshold, the system will enter standby mode. S3: Set the trigger time, shooting delay time, and shooting parameters via the display storage module; S4: The microcontroller control module controls the UV lamp excitation module to turn on and excite the sample for a preset time using UV light. S5: After the excitation time ends, the microcontroller control module simultaneously sends a shutdown command to the ultraviolet lamp excitation module and a shooting command to the image acquisition module, realizing the synchronous execution of light source shutdown and image acquisition; S6: The image acquisition module transmits the acquired afterglow image to the microcontroller control module, which processes it and displays it on the display storage module and automatically stores it. S7: Repeat steps S3-S6 to perform multiple repeated experiments or test different samples.

[0014] Furthermore, in step S5, the microcontroller control module uses software timing logic to control the time difference between turning off the ultraviolet lamp and image acquisition to within 100 milliseconds.

[0015] Application of a closed synchronous imaging system for long afterglow materials based on 3D printing; application of 3D printing structural design and embedded automatic control technology in luminescent material testing devices.

[0016] This invention utilizes 3D printing to create customizable sealed cavities, significantly reducing the processing cost and time required for traditional metal darkrooms. It can flexibly adapt to the installation needs of samples of different sizes and various modules. A microcontroller enables millisecond-level synchronous control of ultraviolet light source shutdown and image acquisition, completely eliminating the fixed time intervals and random errors caused by manual operation, and accurately capturing the initial attenuation data of long-afterglow materials. Integrated real-time light leakage detection and alarm functions effectively avoid interference from ambient stray light on low-light imaging. The system boasts high integration and ease of operation, significantly improving the accuracy, repeatability, and experimental efficiency of afterglow image acquisition, providing a reliable technical means for the performance testing and screening of various long-afterglow materials. Attached Figure Description

[0017] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0018] Figure 1 This is a SOLIDWORKS design drawing of the sealed cavity box of the present invention; Figure 2 This is a SOLIDWORKS design drawing of the sealed cavity cover plate of the present invention; Figure 3 This is a Bambu studio slice illustration of the sealed cavity of the present invention; Figure 4 This is the standard pinout diagram for the STM32F407VE minimum system. Figure 5 A photograph of the actual PCB layout for the STM32F407VE minimum system; Figure 6 OV7670 control timing diagram; Figure 7 Timing diagram for reading data from OV7670; Figure 8 Pin diagram of OV7670 minimum system; Figure 9 This is a picture of the OV7670. Figure 10 Pin diagram of the ILI9341 minimum system; Figure 11 This is a picture of the actual ILI9341. Figure 12 The physical pin definition diagram for the ILI9341 TFT screen module; Figure 13 The minimum system pinout for the XPT2046 display touch module; Figure 14 A physical image of the XPT2046 touch module is shown. Figure 15 This is a schematic diagram of an active buzzer. Figure 16 This is a picture of an active buzzer. Figure 17 This is a physical image of an integrated module combining a photoresistor and a relay. Figure 18 This is a schematic diagram of an integrated module combining a photoresistor and a relay. Figure 19 This is a diagram showing the overall assembly structure of the photoresistor relay integrated module. Figure 20 This is an external view of the sealed imaging system of the present invention; Figure 21 This is an internal view of the sealed imaging system of the present invention; Figure 22 A photograph of a long afterglow material under 365nm lamp illumination; Figure 23 A photograph of the afterglow of a long-afterglow material after being illuminated by a 365nm lamp. Detailed Implementation

[0019] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1 like Figures 1-23 As shown, this invention discloses a closed-loop synchronous imaging system for long afterglow materials based on 3D printing, comprising the following steps: Example 1: Design and fabrication of a 3D-printed sealed cavity Based on the requirements of the closed-loop imaging system for long-afterglow materials, the closed chamber was designed in 3D using SOLIDWORKS software. The overall dimensions of the chamber are 280mm × 150mm × 80mm, and it adopts a pull-out structure design for easy sample placement and removal. The top of the chamber has a 12mm diameter camera lens mounting hole and two symmetrical pull-out slots to ensure convenient experimental operation. A wiring hole with an opening diameter of 50mm, an overall diameter of 60mm, a thickness of approximately 2.5mm, and a depth of approximately 200mm is designed on the side of the chamber to facilitate the connection of power supplies for 254nm and 365nm wavelength lamps. A sealing cap is also designed to match the wiring hole, sealing the opening during imaging to ensure no light leakage. The interior of the chamber has pre-installed mounting positions for the UV lamp, photoresistor module, relay integrated module, and sample stage.

[0021] The designed 3D models of the housing and cover were imported into Bambu Studio software for slicing. In the slicing settings, the side with the largest surface area was positioned to contact the PEI plate surface to prevent insufficient support during printing, which could lead to collapse or burrs and printing failure. The layer thickness was set to 0.2mm, the infill density to 20%, and a linear infill method was used. A Tuozhu A1 mini 3D printer was used for printing, with Bambu PLA Basic black filament selected to improve the light-blocking performance of the cavity. After printing, the support structure was removed, and the edges of the cavity were sanded to ensure a tight seal between the cover and the housing.

[0022] Example 2 Hardware module selection and assembly The microcontroller control module uses an STM32F407VE minimum system board as the main control unit. Based on an ARM Cortex-M4 core with a 168MHz clock speed, this module integrates an FPU floating-point unit and a DSP instruction set, providing excellent real-time processing capabilities. Equipped with 512KB Flash and 192+4KB SRAM, and packaged in a 100-pin LQFP package, the module boasts a rich set of peripheral interfaces, including 3xSPI, 3xUSART, 2xUART, 2xI2S, 3xI2C, 1xFSMC, 1xSDIO, 2xCAN, 1xUSB2.0 FS / HS controller (with dedicated DMA), 1xUSB HS ULPI, 1x10 / 100 Ethernet MAC, 1x8 to 12-bit parallel camera interface, 3x12-bit AD (1µs / time-division 24 channels), and 2x12-bit DA, fully meeting the system's control requirements.

[0023] Image Acquisition Module: Employs the OV7670 CMOS image sensor module. This module, launched by OmniVision, features low cost and low power consumption, supports VGA (640×480) resolution output, and can be configured for lower resolution modes such as QVGA and CIF. The pixel size is 3.6μm×3.6μm, supporting multiple output formats including YUV (422 / 420), RGB (565 / 555), GRB422, and raw RAWBayer. The maximum frame rate in VGA mode can reach 30fps. The module integrates Auto Exposure (AEC), Auto White Balance (AWB), and Automatic Gain Control (AGC) functions, employs an 8 / 10-bit parallel data output interface, and configures registers via the SCCB (I2C-like) protocol. To reduce the timing burden on the main control chip, an external AL422B FIFO memory is used as a data buffer. The main control chip can read data from the FIFO at any time without strictly adhering to the timing control requirements of the CMOS sensor, effectively reducing development complexity and improving system stability.

[0024] Display and storage module: Employs a 2.4-inch ILI9341 TFT LCD touchscreen module. This module, launched by ILITEK, is suitable for 2.2-3.2 inch LCD screens with a resolution of 240×320 (QVGA), supporting 16-bit (RGB565) or 18-bit (RGB666) color modes, enabling 262K color display. The chip supports a 4-wire SPI interface and an 8 / 16-bit parallel interface, with some modules compatible with the I2C interface, offering strong adaptability. It has built-in video memory and supports partial refresh, reducing the load on the main controller. The module integrates an XPT2046 resistive touch chip with a logic level of 3.3V and a backlight power supply typically of 5V. The driver solution is mature and easy to develop. Additionally, the module is equipped with an SD card slot, allowing captured images to be stored on an SD card for subsequent analysis.

[0025] Touch control module: Employs the XPT2046 4-wire resistive touchscreen controller. This chip is compatible with ADS7843 / 7846, communicates with the main controller via an SPI interface (maximum communication rate of 2MHz), supports 12-bit ADC coordinate detection (4096 levels of accuracy), and has built-in temperature detection and touch pressure (Z-axis) measurement functions. The chip operates on a 1.5V~5.5V power supply, is compatible with 3.3V / 5V logic levels, has an operating current of approximately 250μA, a standby current of approximately 1μA, and features mature driver technology that is easy to integrate.

[0026] Ultraviolet lamp excitation module: A 365nm wavelength ultraviolet black light lamp is used as the excitation source. This lamp is connected to the I / O port of the microcontroller control module through a 5V relay, and its on / off timing is controlled by the microcontroller.

[0027] The light leakage detection alarm module consists of an integrated photoresistor and relay module and an active buzzer. The core of the integrated photoresistor and relay module uses a sensitive photoresistor sensor to collect light intensity signals. After processing by a wide-voltage LM393 comparator, a control signal is output to drive the relay. This module is equipped with an adjustable potentiometer to adjust the light intensity detection threshold; it has two output options: DO digital switch output and AO analog voltage output. The comparator output signal is stable, with a drive capability of no less than 15mA; the operating voltage is compatible with 3.3V~5V, and the hardware stability is strong. The module PCB size is 32mm×14mm, with pre-drilled mounting bolt holes for easy installation.

[0028] The active buzzer module integrates an internal oscillation source, eliminating the need for external oscillation circuits and external PWM or square wave drive signals. It sounds at a fixed frequency upon power-up, requiring no software configuration of the drive timing. The operating voltage is compatible with 3.3V to 5V, making it compatible with both 3.3V and 5V microcontrollers. Start and stop are directly controlled by outputting high and low levels through the microcontroller's I / O ports, without consuming timer or PWM resources, simplifying the control method. This buzzer module uses an S8050 transistor driver, with pins defined as GND, I / O, and VCC (GND is the topmost port on the front, followed by I / O and VCC). The PCB size is 32mm × 13mm, with pre-drilled mounting bolt holes for easy installation.

[0029] Assemble the aforementioned hardware modules according to the design requirements. First, fix the UV lamp and photoresistor relay integrated module in their respective positions inside the sealed cavity; then, install the OV7670 camera module in the camera lens mounting hole on the top of the cavity, and adjust the lens angle to align it with the sample stage; finally, install the STM32F407VE minimum system board and ILI9341 TFT touch screen module in the control box outside the cavity, and connect them to the modules inside the cavity via wires. All wires are led out through the wiring holes on the side of the cavity, and the holes are sealed with sealing caps during imaging.

[0030] Example 3 Software system design and debugging The software system of this invention is developed based on the STM32 microcontroller and written in C language. It mainly includes a system initialization module, a light leakage detection module, an ultraviolet lamp control module, an image acquisition module, a display and storage module, and a touch screen interaction module.

[0031] The system initialization module completes the configuration of the microcontroller clock, GPIO port, SPI interface, FSMC interface, timer and interrupt, as well as the initialization settings of the OV7670 camera, ILI9341 display and XPT2046 touch screen.

[0032] The light leakage detection module forms a complete alarm function chain under the control of software logic: the ambient light intensity signal is collected by a photoresistor, and compared with a set threshold after software calculation; the system remains silent in low-light conditions, and when strong light leakage occurs, the relay is activated, driving the buzzer to emit an audible and visual alarm, realizing a closed loop of functions including light detection, relay linkage control, and buzzer prompting. When the detected light intensity exceeds the preset threshold, the buzzer alarm is triggered, and a "light leakage warning" message is displayed on the screen.

[0033] The UV lamp control module controls the relay to turn the UV lamp on and off via the microcontroller's I / O port. The module supports setting the excitation time via a touchscreen, ranging from 1 second to 60 minutes.

[0034] The image acquisition module controls the OV7670 camera to acquire images and stores the acquired image data in a FIFO memory. When the microcontroller receives a shooting command, it reads the image data from the FIFO and performs format conversion and processing.

[0035] The display storage module displays the processed image data on the ILI9341 display screen and can also store the image to an SD card. The stored image files are named in the format "YYYYMMDD_HHMMSS.jpg" for easy retrieval and analysis later.

[0036] The touchscreen interaction module enables user interaction with the system. Users can set system parameters such as trigger time, shooting delay time, exposure time, and gain via the touchscreen, and can also view and delete stored images.

[0037] The core of the software system is to achieve synchronous control of UV lamp shutdown and image acquisition. The afterglow decay of long-afterglow materials follows an exponential law. The initial stage, from tens of milliseconds to several seconds after the lamp is turned off, is the period of rapid brightness decay and represents the core data range characterizing the material's afterglow performance. Existing manual operation methods require manually turning off the lamp power and then manually triggering the image capture, inevitably resulting in a fixed time interval of more than 0.5 seconds, making it impossible to capture the initial afterglow data at the moment the lamp is turned off. Furthermore, the time interval between each operation introduces random errors, leading to non-repeatable experimental data, lack of cross-comparison value, and inability to accurately represent the true decay law of the material. This invention, through precise software timing logic, sets the lamp shutdown command and camera capture command to be issued synchronously in the program. Through coordinated optimization of hardware circuitry and software timing, the time difference between the two actions is controlled within milliseconds, completely eliminating the fixed time interval and random errors of manual operation. This allows for precise capture of the initial decay data of long-afterglow materials at the moment the lamp is turned off. Simultaneously, the triggering timing is completely consistent for each experiment, ensuring strong repeatability of experimental data and accurately characterizing the true afterglow decay law of long-afterglow materials.

[0038] Example 4 System testing and use like Figures 1-23 As shown, after the system assembly and debugging were completed, afterglow photography tests on long-afterglow materials were conducted. The sealed imaging system was finally assembled, integrating a 365nm ultraviolet lamp, a photosensitive alarm module, and an OV7670 camera module inside the sealed cavity. The ultraviolet lamp serves as the excitation light source for the long-afterglow materials, and its on / off timing is controlled by a relay through the main control I / O port, precisely linked with the camera's shooting logic.

[0039] This invention uses a 365nm ultraviolet lamp as the excitation source, which has significant advantages over conventional UV LED beads: First, the lamp's main wavelength is precisely matched with the optimal excitation band of long-afterglow materials, resulting in high excitation efficiency and fully excitation of the material's luminescent center, ensuring stable and controllable afterglow effects. Second, the lamp is a line light source, enabling uniform irradiation of the entire sample surface within the limited space of the cavity, eliminating bright and dark areas and ensuring uniform brightness and reliable data in the captured afterglow image. Third, the dedicated black light lamp has no visible light stray output, preventing diffuse reflection stray light from forming within the cavity, avoiding interference with the light leakage detection system of the photoresistor, and eliminating experimental misjudgments. Fourth, the lamp's luminous characteristics are stable, with minimal light decay throughout its lifespan, and it can be precisely matched with the system's "excitation-delay-imaging" timing control logic, ensuring the repeatability of experimental results. Furthermore, its driving circuit is extremely simple and seamlessly compatible with existing relay control hardware, requiring no additional modifications to the system design.

[0040] The testing steps are as follows: Open the pull-out cover of the sealed cavity, place the long afterglow material sample to be tested on the sample stage, and adjust the sample position so that it is in the center of the camera's field of view; Close the pull-out cover and seal the wiring holes on the side with sealing caps; When the system power is turned on, the system will automatically perform light leakage detection. If the buzzer sounds an alarm, it indicates that there is light leakage in the cavity. The sealing of the cover plate and wiring holes needs to be checked until the light leakage alarm is cleared. Set the trigger time to 10 minutes, the shooting delay time to 0 seconds, and the exposure time to 1 second via the touchscreen; Click the "Start Experiment" button, and the system will automatically turn on the UV lamp to excite the sample for 10 minutes. After the excitation time ends, the system immediately turns off the ultraviolet lamp and simultaneously triggers the camera to take pictures; After the image is taken, the afterglow image is displayed on the screen and automatically saved to the SD card; By repeating the above steps, different long-afterglow material samples were tested, and a series of comparable afterglow images were obtained.

[0041] Test results show that the system of the present invention can stably and accurately acquire afterglow images of long afterglow materials. The brightness and attenuation state of the images from different experiments are consistent, which fully meets the requirements for performance testing and screening of long afterglow materials.

[0042] The present invention has the following beneficial effects: Using 3D printing to prepare sealed cavities allows for rapid customization of structures based on sample size, light source position, camera aperture position, and sensor installation requirements. This reduces the processing cost and manufacturing cycle of traditional metal darkrooms and improves the flexibility and adaptability of the device.

[0043] By controlling the start and stop of the ultraviolet excitation light source with a microcontroller, and automatically triggering the camera module to take pictures at the same time as the light source is turned off or after a set delay, the time difference between the two actions is controlled within milliseconds, completely eliminating the uncertain time error between manually turning off the light and manually taking pictures, improving the time consistency of afterglow photo acquisition, and accurately capturing the initial attenuation data of long afterglow materials at the moment the light tube is turned off.

[0044] Using ultraviolet lamps as the excitation source provides relatively uniform linear irradiation. The main wavelength is precisely matched with the optimal excitation band of the long-afterglow material, resulting in high excitation efficiency. Furthermore, the dedicated black light lamp has no visible light stray output, preventing the formation of diffuse reflection stray light within the cavity and avoiding interference with the light leakage detection system of the photoresistor.

[0045] A light leakage detection alarm module is set up so that an alarm can be triggered in time when the light intensity in the sealed cavity exceeds a preset threshold, thereby improving the reliability of the shooting environment in low afterglow and avoiding experimental failure due to light leakage.

[0046] It integrates image acquisition, parameter adjustment, real-time display and storage functions, which facilitates the rapid recording of afterglow photographs of long afterglow materials, repeated experiments and sample comparison analysis, thereby improving experimental efficiency and result reproducibility.

[0047] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A closed-loop synchronous imaging system for long afterglow materials based on 3D printing, characterized in that, include: The 3D-printed polymer sealed cavity adopts a pull-out structure design. The top is reserved with a camera lens mounting hole and a pull-out slot, the side is provided with wiring holes and matching sealing caps, and the interior is reserved with installation positions for light sources, sensors and control modules. The ultraviolet lamp excitation module is installed inside the sealed cavity of the 3D printed polymer to provide uniform ultraviolet excitation light for the long afterglow material. The microcontroller control module is electrically connected to the ultraviolet lamp excitation module, image acquisition module, display and storage module, and light leakage detection and alarm module, respectively, and is used to control the timing operation of the entire system. The image acquisition module is installed at the camera lens mounting hole at the top of the sealed cavity and is used to acquire afterglow images of long afterglow materials. The display storage module is electrically connected to the microcontroller control module and is used to display system parameters, provide real-time previews, and store the acquired afterglow images. The light leakage detection alarm module is installed inside a sealed cavity to detect the light intensity inside the cavity in real time. When the light intensity exceeds a preset threshold, an alarm signal is issued.

2. The closed-loop synchronous imaging system for long afterglow materials based on 3D printing according to claim 1, characterized in that, The 3D-printed polymer sealed cavity is made of PLA material using 3D printing technology.

3. The closed-loop synchronous imaging system for long afterglow materials based on 3D printing according to claim 1, characterized in that, The ultraviolet lamp excitation module is an ultraviolet black light lamp with a wavelength of 365nm or 254nm. It is electrically connected to the microcontroller control module through a relay, and its on / off timing is controlled by the microcontroller.

4. The closed-loop synchronous imaging system for long afterglow materials based on 3D printing according to claim 1, characterized in that, The microcontroller control module uses an STM32F407VE microcontroller as the main control chip.

5. The closed-loop synchronous imaging system for long afterglow materials based on 3D printing according to claim 1, characterized in that, The image acquisition module uses an OV7670 CMOS image sensor, supports VGA (640×480) resolution output, and has built-in automatic exposure, automatic white balance and automatic gain control functions. It is connected to the microcontroller control module through an external FIFO memory.

6. The closed-loop synchronous imaging system for long afterglow materials based on 3D printing according to claim 1, characterized in that, The display and storage module uses an ILI9341 TFT LCD screen with an integrated XPT2046 resistive touch chip, which supports 16-bit RGB565 color mode and is connected to the microcontroller control module via an SPI interface.

7. The closed-loop synchronous imaging system for long afterglow materials based on 3D printing according to claim 1, characterized in that, The light leakage detection alarm module includes a photoresistor sensor, an LM393 comparator, a relay, and an active buzzer. The photoresistor sensor collects the light intensity signal inside the cavity, which is processed by the LM393 comparator and outputs a control signal. When the light intensity exceeds a preset threshold, the relay is activated, driving the active buzzer to emit an alarm sound. The light leakage detection alarm module is also equipped with an adjustable potentiometer for adjusting the light intensity detection threshold.

8. A method for closed-loop synchronous imaging of long afterglow materials based on 3D printing, characterized in that, Using the system as described in any one of claims 1-7 includes the following steps: S1: Place the long afterglow material sample to be tested on the sample stage inside the sealed cavity, close the cavity cover and seal the side wiring holes. S2: Start the system. The light leakage detection alarm module automatically detects the light intensity inside the cavity. If the light intensity exceeds the preset threshold, the buzzer will sound an alarm to indicate that there is light leakage. If the light intensity is lower than the preset threshold, the system will enter standby mode. S3: Set the trigger time, shooting delay time, and shooting parameters via the display storage module; S4: The microcontroller control module controls the UV lamp excitation module to turn on and excite the sample for a preset time using UV light. S5: After the excitation time ends, the microcontroller control module simultaneously sends a shutdown command to the ultraviolet lamp excitation module and a shooting command to the image acquisition module, realizing the synchronous execution of light source shutdown and image acquisition; S6: The image acquisition module transmits the acquired afterglow image to the microcontroller control module, which processes it and displays it on the display storage module and automatically stores it. S7: Repeat steps S3-S6 to perform multiple repeated experiments or test different samples.

9. The method for closed-loop synchronous imaging of long afterglow materials based on 3D printing according to claim 8, characterized in that, In step S5, the microcontroller control module uses software timing logic to control the time difference between turning off the ultraviolet lamp and image acquisition to within 100 milliseconds.

10. An application of a closed-loop synchronous imaging system for long afterglow materials based on 3D printing, characterized in that, Application of 3D printing structural design and embedded automatic control technology in luminescent material testing devices.

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