A cold and hot light source switching imaging system for eye visual training

Abstract

This invention discloses a cold / hot light source switching imaging system for ocular vision training, belonging to the field of medical device technology. The system includes: a light source integration module that generates and outputs cold and hot light; a spectral modulation and beam combining module that integrates the two light sources into a coaxial, temporally combined beam through polarization control and beam combining technology; a digital micromirror array imaging module that modulates the beam according to the training content and projects an image; a synchronization control module that precisely coordinates the synchronization of light source switching and image display; and a human-computer interaction module that receives user input and displays the system status, while simultaneously receiving and displaying the system's operating status from the synchronization control module in real time. This invention aims to solve the problems of non-coaxial imaging optical paths, slow switching speeds, and large size in existing systems, achieving highly coaxial optical paths and microsecond-level rapid switching, thus improving the accuracy, reliability, and convenience of vision training.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and in particular to an imaging system for switching between hot and cold light sources for eye vision training. Background Technology

[0002] Visual training and rehabilitation is an important branch of ophthalmology and optometry, aiming to improve or restore the visual function of the human eye through specific optical stimulation and training methods. Among these methods, using light sources of different properties to alternately stimulate the eye, thereby regulating ciliary muscle tension and improving ocular microcirculation, is one of the effective means to enhance visual acuity and relieve eye strain.

[0003] Among them, alternating hot and cold light source imaging training is a specific technical direction. Its basic principle is to control two light sources with different wavelengths or properties, cold light and hot light, and alternately project them onto the trainee's retina according to a preset program, thereby achieving differentiated stimulation and regulation of the eye tissue.

[0004] Existing technologies typically employ two independent light source systems to provide cold and hot light respectively, switching between them mechanically or electronically. However, this discrete system has significant drawbacks: the optical paths of the two light sources are difficult to achieve complete coaxiality and precise overlap, causing positional drift or parallax in the training images during switching, severely impacting the trainee's visual positioning and concentration; secondly, the mechanical switching mechanism is slow and prone to wear, unable to support the demands of high-frequency, precise, instantaneous switching, limiting the diversity and effectiveness of training modes; furthermore, discrete systems are bulky, consume high power, and have complex optical path calibration, hindering portability and daily use and maintenance. These technical bottlenecks collectively result in deficiencies in stimulation accuracy, response speed, and user experience in existing training systems, making it difficult to meet the requirements of efficient, accurate, and convenient modern visual training. Summary of the Invention

[0005] The purpose of this invention is to provide a switching imaging system for hot and cold light sources for eye vision training, in order to solve the problems of existing discrete hot and cold light source systems, such as image drift during switching due to non-coaxial imaging optical paths, slow mechanical switching response speed and low reliability, as well as large system size and complex calibration.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A switching imaging system for hot and cold light sources for eye vision training includes:

[0008] The light source integration module generates and outputs the initial cold and hot light beams. The module incorporates a multi-band semiconductor light-emitting unit, which integrates at least two independently controllable light-emitting chip groups within a single package. The first chip group is configured to emit cold light with a center wavelength in the 450 nm to 495 nm band, and a spectral half-width of less than 20 nm. The second chip group is configured to emit hot light with a center wavelength in the 620 nm to 750 nm band, and a spectral half-width of less than 25 nm. Each chip group is connected to an independent constant current drive circuit, which receives a pulse width modulation signal from the synchronization control module to achieve 256 levels of linear adjustment of the output light intensity. The output of the light source integration module is coupled to the corresponding input ports of the spectral modulation and beam combining modules via polarization-maintaining optical fibers.

[0009] The spectral modulation and beam combining module performs spectral shaping and spatial beam combining on the input cold and hot light beams to generate a single-outgoing temporally composite beam. The module includes a cold light modulation channel, a hot light modulation channel, and a polarization beam splitter beam combiner. The cold light modulation channel consists of a beam collimator, a first bandpass filter, and a first polarization controller arranged sequentially. The beam collimator converts the cold light output from the fiber into collimated parallel light. The first bandpass filter further filters out stray light within ±10 nm of the center wavelength. The first polarization controller adjusts the polarization state of the cold light beam to S-polarized light. The hot light modulation channel has a symmetrical structure to the cold light modulation channel, including a second beam collimator, a second bandpass filter, and a second polarization controller, which ultimately adjusts the polarization state of the hot light beam to P-polarized light. The polarization beam splitter beam combiner is located at the intersection of the output optical paths of the two modulation channels, and its characteristic is to reflect S-polarized light and transmit P-polarized light. The cold S-polarized light and the hot P-polarized light, after polarization control, are spatially superimposed inside the prism, and output as a coaxial and orthogonally polarized time-composite beam from the same exit end.

[0010] The digital micromirror array (DMI) imaging module generates dynamic images based on the training content and modulates the temporally composited beam output from the spectral modulation and beam combining module into a corresponding spatial light distribution, which is then projected onto the trainee's eye. At the core of this module is a digital micromirror device with a 1024×768 pixel array, each micromirror measuring 10.8 micrometers, and a switching response time of less than 20 microseconds. The DMI is configured to switch rapidly between two operating states: state 1 reflects the incident cold light beam onto the projection lens path; state 2 reflects the incident hot light beam onto the same projection lens path. The projection lens group converges and corrects the imaging light reflected from the DMI, ultimately forming a clear, coaxial training image on the eye's imaging plane located at the system's exit pupil. The distance between the imaging plane of the DMI and the system's exit pupil is precisely designed to be 2 meters optical infinity to induce a relaxed accommodative state in the trainee's eyes.

[0011] The synchronization control module, serving as the system's timing and logic hub, coordinates the precise synchronization of light source switching, image rendering, and training processes. The synchronization control module comprises a field-programmable gate array (FPGA) main controller, along with connected light source driver interfaces, digital micromirror array (DMI) driver interfaces, and an image data buffer. The FPGA main controller internally contains precise timing logic, generating two sets of synchronization control signals with a basic time unit of 1 microsecond. The first set of control signals is the light source switching sequence, which, according to a preset training protocol, sends instructions to the constant current drive circuit of the light source integrated module, controlling the cold light and hot light chipsets to alternately or mix and illuminate at specific frequencies, duty cycles, and intensities. The second set of control signals is the image frame synchronization signal, which is strictly phase-locked with the light source switching sequence, ensuring that the corresponding image frame data is sent to the DMI imaging module within 5 microseconds after each light source state switch. The image data buffer stores multiple sets of training pattern sequences, each containing image content corresponding to the cold light and hot light stages, respectively. The synchronization control module is also responsible for running the visual training protocol parser, which dynamically calculates and generates the corresponding light source switching sequence and image frame sequence based on the training mode and parameters set by the human-computer interaction module.

[0012] The human-machine interface (HMI) module receives user input and displays system status. It includes a touchscreen display, physical control knobs and buttons, and an embedded microprocessor. The touchscreen provides a graphical user interface for selecting training modes and setting training parameters, including single training duration, alternation frequency of hot and cold light, light intensity ratio, and training pattern type. The physical control knobs are used for real-time fine-tuning of the projected light intensity. The embedded microprocessor runs the user interface logic and converts the user's settings into protocol instructions, which are then sent to the synchronization control module via the communication bus. Simultaneously, the HMI module also receives and displays the system's operating status from the synchronization control module in real time, including the current training progress, light source operating mode, and remaining training time.

[0013] In one embodiment of the present invention, the precise synchronization process implemented by the synchronization control module is as follows: The field-programmable gate array (FPGA) main controller internally includes a global timer and a state machine. The state machine defines a periodic timing sequence including a cold light period, a hot light period, and a transition period based on the loaded training protocol. At the beginning of the cold light period, the state machine triggers the first control event, i.e., sends a command to the light source drive interface to turn on the drive current of the cold light chipset and simultaneously turn off the drive current of the hot light chipset. Two microseconds after the triggering of the first control event, the state machine triggers the second control event, i.e., reads the image frame data corresponding to the cold light period from the image data buffer and sends it to the digital micromirror device through the digital micromirror array (DMI) drive interface. The control flow of the hot light period is symmetrical to that of the cold light period, but the image frame data corresponding to the hot light period is loaded. The transition period is used to achieve a smooth intensity gradient from cold light to hot light or from hot light to cold light. The field programmable gate array main controller uses pulse width modulation technology to linearly reduce the driving current of the current light source to 0 within 1 millisecond, while linearly increasing the driving current of the light source in the next cycle from 0 to the target value. During this period, the image content displayed by the digital micromirror device remains unchanged.

[0014] The training protocol parser supports multiple predefined training modes, including alternating flashing mode, gradual fusion mode, and random stimulation mode. In alternating flashing mode, cold light and hot light periods alternate in equal duration, switching instantaneously without a transition period, suitable for high-intensity contrast stimulation. In gradual fusion mode, each cycle includes a longer transition period, making the intensity change curves of cold and hot light sinusoidal, suitable for gentle stimulation modulation. In random stimulation mode, the durations of cold and hot light periods are randomly generated within a preset range, designed to disrupt the trainee's rhythmic expectations and enhance training attention. Based on the selected mode and parameters, the parser generates the corresponding timing parameter table in real time and loads it into the state machine.

[0015] As one embodiment of the present invention, the projection lens group of the digital micromirror array imaging module adopts an apochromatic design, which includes three lens elements made of anomalously dispersed glass to correct chromatic aberration and spherical aberration in the full wavelength range of 450 nm to 750 nm, ensuring that the spatial positions of the images formed by cold light and hot light are completely superimposed on the retina, and the image plane drift is less than 5 micrometers in diameter of a single cone cell.

[0016] Furthermore, the eye vision training system with hot and cold light source switching also integrates an eye-tracking and feedback adjustment subsystem. This subsystem includes a near-infrared illumination unit, a high-speed camera, and an image processing coprocessor integrated into the synchronization control module. The near-infrared illumination unit uniformly illuminates the trainee's eye area with invisible light at a wavelength of 850 nanometers. The high-speed camera captures eye-tracking video streams at a frame rate of 200 Hz. The image processing coprocessor runs a pupil center localization algorithm to calculate in real time the deviation of the trainee's gaze point relative to the center position of the training image. When the deviation persists for more than 3 degrees of visual field for 500 milliseconds, the image processing coprocessor sends a signal to the synchronization control module. The synchronization control module then dynamically fine-tunes the display position of the next frame of the training image on the digital micromirror array, performing real-time offset compensation to ensure that the image content remains stable within the trainee's central visual field.

[0017] In one embodiment of the present invention, the multi-band semiconductor light-emitting unit of the light source integration module adopts flip-chip packaging technology to integrate the cold light-emitting chip and the hot light-emitting chip on the same ceramic substrate, sharing the same heat sink. This structure ensures that the optical center distance between the two light-emitting chips is less than 0.5 mm, thus guaranteeing a high degree of coaxiality of the subsequent optical path from the physical source.

[0018] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0019] This invention achieves highly coaxial output of cold light and hot light in a single optical path through the coordinated design of the light source integration module, spectral modulation and polarization beam combining module; the polarization beam splitter beam combining technology ensures the precise superposition of the two types of light in space, eliminates the parallax and image drift problems inherent in traditional discrete systems, provides a stable and accurate stimulus target for visual training, and significantly improves the effectiveness of training and user experience.

[0020] This invention employs an all-solid-state electronic switching scheme, eliminating mechanical moving parts. Through a synchronous control module, it achieves nanosecond-level precise synchronous control of the semiconductor light source and the digital micromirror array, enabling microsecond-level instantaneous switching between hot and cold light sources and corresponding image content. The system supports a wide range of alternating frequencies from 0.1 Hz to 50 Hz and can realize complex light intensity gradient modes, breaking through the bottlenecks of mechanical switching in terms of speed, accuracy, and reliability, and greatly expanding the modes and performance limits of visual training.

[0021] The highly integrated design of this invention compactly integrates multi-band light sources, beam combiners, spatial light modulators, and control units, significantly reducing system size and power consumption. Once the optical path is factory-calibrated, it remains permanently stable, eliminating the need for users to perform tedious optical path alignment and maintenance. Combined with the eye-tracking feedback subsystem, the system achieves intelligent human-computer interaction and adaptive adjustment, making the device easy to operate and portable, and able to meet the needs of efficient and convenient visual training in clinical institutions and home settings. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall technical architecture of the cold and hot light source switching imaging system for eye vision training proposed in this invention.

[0023] Figure 2 This is a schematic diagram of the core principle framework proposed in this invention based on polarization beam combining and synchronous switching of electrons. Detailed Implementation

[0024] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely intended to explain the present invention and not to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present invention by illustrating examples of the invention.

[0025] Example 1

[0026] This invention provides an imaging system for switching between hot and cold light sources for eye vision training, the overall technical architecture of which is shown in the attached figure. Figure 1 As shown, the system consists of five functional units: a light source integration module, a spectral modulation and beam combining module, a digital micromirror array imaging module, a synchronization control module, and a human-computer interaction module. These units are tightly coupled and work together through a precision optical path and a high-speed electronic signal bus, thereby ensuring the coaxiality, instantaneous switching, and image stability of cold and hot light stimuli at the physical level.

[0027] The light source integration module serves as the optical energy source for the entire system. Its core is a multi-band semiconductor light-emitting unit. This unit utilizes flip-chip packaging technology, integrating the first and second light-emitting chip groups onto the same high thermal conductivity ceramic substrate and sharing a metal heat sink. The first light-emitting chip group is dedicated to emitting cold light with a center wavelength between 450 nm and 495 nm, with a typical center wavelength set at 470 nm and a spectral half-width of less than 20 nm. The second light-emitting chip group emits hot light with a center wavelength between 620 nm and 750 nm, with a typical center wavelength set at 660 nm and a spectral half-width of less than 25 nm. The two light-emitting chip groups are spatially arranged extremely compactly, with the optical center distance between their respective emitting surfaces less than 0.5 mm, ensuring a high degree of coaxiality in the subsequent optical path from the source. Each light-emitting chip group is connected to an independent constant current drive circuit. This circuit receives pulse width modulation signals from the synchronization control module and can linearly adjust the output light intensity in 256 levels with an adjustment accuracy better than 0.4%. The output ports of the light source integration module are led out through two polarization-maintaining optical fibers. One fiber transmits a cold light beam, and the other transmits a hot light beam. The two fibers are respectively connected to the corresponding input ports of the spectral modulation and beam combining module.

[0028] The spectral modulation and beam combining module functions to perform spectral purification, polarization state adjustment, and spatial beam combining on the two initial beams from the light source integration module, ultimately forming a coaxial and orthogonally polarized temporally composite beam. (See attached...) Figure 2The schematic diagram illustrates the principle framework. This module includes a cold light modulation channel, a hot light modulation channel, and a polarization beam splitter and combiner. The cold light modulation channel, arranged sequentially along the light propagation direction, comprises a beam collimator, a first bandpass filter, and a first polarization controller. The beam collimator receives the diverging cold light output from the polarization-maintaining fiber and converts it into a collimated parallel beam with a divergence angle less than 0.5 degrees. The center wavelength of the first bandpass filter matches the first light-emitting chip group, with a bandwidth of ±10 nanometers, used to filter out stray radiation components other than the main peak, improving spectral purity. The first polarization controller consists of a liquid crystal phase retarder and a polarization rotator, precisely adjusting the polarization direction of the cold light beam to an S-polarization state. The hot light modulation channel adopts a symmetrical structure, including a second beam collimator, a second bandpass filter, and a second polarization controller. Its function is to collimate, filter, and adjust the hot light beam to a P-polarization state. The polarization beam combiner is located at the intersection of the outputs of the two modulation channels. Its interior is coated with multiple dielectric films, exhibiting a high reflectivity of over 98% for S-polarized light and a high transmittance of over 95% for P-polarized light. The polarization-controlled cold S-polarized light is incident at a 45-degree angle onto the prism's inclined surface and reflected, while the hot P-polarized light is transmitted into the prism at the same angle. The two beams completely overlap at the prism's exit surface and exit as a single beam from the same outlet. The temporally combined beam contains only one type of light (cold or hot) at any given time, or both during a specific transition period with controlled intensity, and always maintains strictly coaxial propagation characteristics.

[0029] The digital micromirror array (DMI) imaging module is responsible for modulating the aforementioned temporally composite beam into a spatially controllable dynamic training image and precisely projecting it onto the trainee's eye. The core component of the DMI imaging module is a digital micromirror device with a micromirror array specification of 1024×768 pixels. Each micromirror has a physical size of 10.8 micrometers, and its surface material is a high-reflectivity aluminum film with a surface roughness of less than 2 nanometers. Each micromirror can rapidly flip between two angles of +12 degrees and -12 degrees, with a switching response time of less than 20 microseconds. In system operation, the DMI device is configured with two logical operating states: State 1 corresponds to the cold light period, where all micromirrors reflect the incident cold S-polarized light to the main optical path of the projection lens group; State 2 corresponds to the hot light period, where the micromirrors reflect the incident hot P-polarized light to the same main optical path. Because the cold and hot light are combined into a coaxial beam before entering the digital micromirror device, the reflected light always enters the projection lens assembly along the exact same path, regardless of the light source, fundamentally eliminating image position drift caused by light source switching. The projection lens assembly employs an apochromatic optical design, consisting of three lens elements made of special anomalously dispersed glass, with a focal length of 50 mm and a numerical aperture of 0.12. The projection lens assembly has undergone chromatic and spherical aberration correction across the entire visible spectrum from 450 nm to 750 nm, ensuring that the images formed by the cold and hot light have a completely consistent focal position and geometry on the eye's imaging plane at the system's exit pupil. The system's exit pupil is precisely set at optical infinity, 2 meters away from the last lens of the projection lens, allowing the trainee's eyes to be naturally relaxed and accommodative when viewing the image, avoiding eye strain caused by close-range focusing that could interfere with the training effect. Through actual testing, it has been verified that under this design, the image plane drift caused by imaging with cold light and hot light is less than 5 micrometers, which is lower than the average diameter of a single cone cell in the fovea of ​​the human retina, thus ensuring the spatial consistency of visual stimulation.

[0030] The synchronization control module, serving as the timing hub and logic engine of the entire system, undertakes the core task of coordinating light source switching, image rendering, and timing synchronization. Built around a field-programmable gate array (FPGA) main controller, the module integrates a global timer, a finite state machine, a dual-channel signal generator, and a high-speed data interface. The FPGA main controller runs a fixed hardware description logic, generating two sets of strictly synchronized control signals with a basic time unit of 1 microsecond. The first set is the light source switching sequence signal, sent to the constant current drive circuit in the light source integrated module via the light source driver interface, precisely controlling the on / off timing, drive current amplitude, and pulse width modulation duty cycle of the first and second light-emitting chipsets. The second set is the image frame synchronization signal, connected to the dedicated driver chip of the digital micromirror device via the digital micromirror array (DMI) driver interface, used to trigger the loading and display of image frames. The image data buffer uses a dual-port static random access memory (SRAM) with a capacity of 64 megabytes, pre-stored with multiple sets of training pattern sequences. Each sequence set contains a set of image frames A corresponding to the cold light stage and a set of image frames B corresponding to the hot light stage. The content of these two sets can be the same or different to support diverse training strategies such as contrast, complementarity, or alternation. The synchronization control module also embeds a visual training protocol parser. This parser dynamically calculates and generates the corresponding periodic time series table based on the training mode instructions and parameters passed from the human-computer interaction module, and loads it into a finite state machine for execution. Parameters include frequency, light intensity ratio, or duration; training mode instructions include alternating flashing, gradual fusion, or random stimulation.

[0031] In the specific synchronization process, the finite state machine defines a complete cycle according to the current training protocol. This cycle can be divided into a cold light period, a hot light period, and an optional transition period. When the start of the cold light period arrives, the state machine first triggers the first control event: sending a high-level enable signal to the light source driver interface to activate the constant current drive circuit of the first light-emitting chip group, and simultaneously sending a shutdown command to the second light-emitting chip group. This action is completed within 1 microsecond. Subsequently, after a precise delay of 2 microseconds after the triggering of the first control event, the state machine triggers the second control event: reading the image frame data corresponding to the current cold light period from the image data buffer and pushing it to the digital micromirror array driver interface via a high-speed parallel bus. This 2-microsecond delay is used to compensate for the time window required for the light source to be lit and for the optical path to stabilize, ensuring that a stable light intensity is available when the image is loaded. The control flow of the hot light period is completely symmetrical, only switching the activated object to the second light-emitting chip group and loading the corresponding frame from the image frame set B. During the transition period, the field-programmable gate array (FPGA) main controller uses a linear interpolation algorithm to generate continuously varying pulse-width modulation (PWM) signals, controlling the driving current of the current light source to linearly decrease from the target value to 0 within 1 millisecond, while the driving current of the next light source linearly increases from 0 to the target value. During this period, the digital micromirror device (DMM) maintains the displayed image content from the previous stage, thus achieving a smooth transition in light intensity without image jumps. The timing jitter of the entire switching process is less than 0.5 microseconds, ensuring the continuity and comfort of visual perception.

[0032] The human-computer interaction module provides users with an intuitive and convenient operation interface and status feedback interface. This module consists of a 7-inch capacitive touchscreen display, a set of physical control knobs and buttons, and an embedded microprocessor. The touchscreen display runs a graphical user interface based on a real-time operating system. The main interface includes a training mode selection area, a parameter setting panel, and a real-time status dashboard. Users can select one of three preset training modes via touch operation: In alternating flashing mode, cold light and hot light periods alternate for equal durations, with a typical cycle of 20 milliseconds (50 Hz), switching instantaneously without a transition period, suitable for high-intensity contrast sensitivity training; in gradual fusion mode, each cycle includes a transition period of up to 500 milliseconds, with cold and hot light intensities changing according to a sine function, used to gently adjust visual adaptation; in random stimulation mode, the duration of cold and hot light periods is randomly generated within the range of 100 to 2000 milliseconds, breaking rhythm expectations and improving attention concentration. The parameter setting panel allows users to set the total duration of a single training session, the frequency of alternation between cold and hot light, the relative intensity ratio of cold and hot light, and the type of training pattern. The total duration of a single training session ranges from 1 minute to 30 minutes; the frequency of alternating hot and cold light ranges from 0.1 Hz to 50 Hz; the relative intensity ratio of hot to cold light ranges from 1:9 to 9:1; and the training pattern types include letter recognition, pattern tracking, and dynamic gratings. A physical control knob is used to fine-tune the volumetric light intensity in real time during training, with an adjustment range covering 0 to the maximum safe brightness, conforming to the IEC 62471 photobiological safety standard. An embedded microprocessor parses user input, encapsulates it into standard communication protocol instructions, and sends them to the synchronization control module via the SPI bus at a rate of 10 megabits per second. Simultaneously, the human-machine interface module continuously receives system status data packets from the synchronization control module, including the current training progress percentage, light source operating status indicator, remaining time countdown, and eye-tracking feedback flags, and displays them graphically on the touchscreen in real time.

[0033] The eye-tracking and feedback adjustment subsystem for visual training integrates a hot / cold light source switching imaging system to achieve adaptive localization of training images. This subsystem consists of three parts: a near-infrared illumination unit, a high-speed camera, and an image processing coprocessor. The near-infrared illumination unit uses an array of light-emitting diodes with a center wavelength of 850 nm to uniformly illuminate the trainee's eye area at a low intensity of less than 10 lux, ensuring the illumination is invisible and does not interfere with the main training optical path. The high-speed camera is a global shutter CMOS sensor with a resolution of 640×480 pixels and a fixed frame rate of 200 Hz. The raw video stream is transmitted to the image processing coprocessor within the synchronization control module via a USB 3.0 interface. The image processing coprocessor runs an optimized pupil center localization algorithm. This algorithm first performs Gaussian filtering for noise reduction on each frame, then uses adaptive thresholding to extract the pupil region, and finally calculates the pupil center coordinates using the centroid method. The eye-tracking and feedback adjustment subsystem converts these coordinates into a visual angle deviation relative to the center of the training image, in degrees. When the absolute value of the deviation persists for more than 3 degrees for 500 milliseconds, the coprocessor determines that the trainee's gaze has significantly deviated from the central visual field and immediately sends an offset compensation request signal to the field-programmable gate array (FPGA) main controller. Upon receiving this signal, the main controller dynamically modifies the display start address of the image data on the digital micromirror array before loading the next frame, causing the entire training pattern to undergo a displacement in the micromirror plane opposite to the direction of eye movement. This displacement, magnified by the projection lens, forms an equivalent reverse movement on the eye's imaging plane, thereby pulling the image content back into the trainee's central visual field. The compensation accuracy can reach 0.1 degrees of visual angle, effectively maintaining the effectiveness of the training stimulus and concentration.

[0034] In summary, this embodiment deeply integrates five core technologies—multi-band integrated light source, polarization beam combining optical path, high-speed digital micromirror modulation, nanosecond-level electronic synchronization control, and intelligent eye-tracking feedback—to construct a highly integrated, coaxially stable, rapidly switching, and intelligently operated ocular vision training platform. The system undergoes a one-time precision calibration of the entire optical path before leaving the factory, ensuring long-term stable performance without user intervention. Its dimensions are less than 30 cm × 20 cm × 15 cm, and its weight is less than 2 kg, making it suitable for professional rehabilitation training in ophthalmology clinics as well as convenient for daily use in a home environment.

[0035] Example 2

[0036] Building upon Example 1, this example further optimizes the light source integration module and synchronization control logic to support more complex multispectral hybrid training modes. Specifically, the multi-band semiconductor light-emitting unit in the light source integration module is expanded to include a structure with three independent light-emitting chip groups. In addition to the original first light-emitting chip group (cold light 470 nm) and the second light-emitting chip group (hot light 660 nm), a third light-emitting chip group is added, which emits green light with a center wavelength of 525 nm and a spectral half-width of less than 18 nm, used to provide intermediate color temperature stimulation. The three light-emitting chip groups are still integrated on the same ceramic substrate, with an optical center spacing of less than 0.5 mm, and each is connected to an independent constant current drive circuit, supporting 256 levels of light intensity tuning.

[0037] Correspondingly, the spectral modulation and beam combining module has also undergone structural upgrades. The original polarization beam splitter beam combiner has been replaced with a three-port polarization beam combining cube, which contains two orthogonally arranged polarization beam splitting film layers. The cold light modulation channel outputs S-polarized light, the hot light modulation channel outputs P-polarized light, and the newly added green light modulation channel is adjusted to 45-degree linearly polarized light by a third polarization controller. After entering the beam combining cube, this 45-degree polarized light is decomposed into equal-amplitude S and P components, which are superimposed with the original cold and hot light, respectively, and finally output from a single outlet as a composite beam containing three polarization state components. Since the digital micromirror device has high reflectivity for any polarization state, this composite beam can be completely reflected to the projection lens group.

[0038] The field-programmable gate array (FPGA) main controller of the synchronization control module has been reconfigured to support independent control of three light sources. Its internal state machine can define complex cycles including cool light, hot light, green light, and multi-source mixing periods. During the mixing period, the three light-emitting chips can be lit simultaneously in any ratio, such as generating white light (cool:green:hot = 3:6:1) or mixed light with a specific color temperature. The image data buffer is correspondingly expanded into three sets of image frames, A, B, and C, corresponding to the three monochromatic light sources, or a weighted composite image can be used during the mixing period. The training protocol parser adds a "multi-color mixing mode," allowing users to set the intensity weight curves of each light source, the mixing sequence, and the corresponding image content. For example, a gradient cycle can be designed: starting with pure cool light, gradually adding green light to form cyan, then adding hot light to form white, and finally fading to pure hot light, accompanied by dynamic changes in image content throughout. This mode can be used for color vision deficiency correction or advanced contrast sensitivity training.

[0039] Furthermore, the image processing coprocessor of the eye-tracking subsystem has been enhanced to support color-based gaze point analysis. When the system is in multi-color blending mode, the coprocessor not only calculates the pupil center position but also analyzes the differences in the iris's reflectivity to different wavelengths of light, helping to determine the trainee's gaze preference for specific colors of light. If it is found that the user consistently avoids a certain wavelength of light stimulation, the system can automatically increase the probability of that wavelength's appearance or adjust its spatial position to achieve personalized intervention.

[0040] While maintaining the original advantages of coaxiality and high-speed switching, this embodiment expands the system function from dual-color switching to multi-color dynamic mixing, significantly improving the dimensionality and flexibility of visual training, and making it suitable for a wider range of clinical rehabilitation scenarios.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A switching imaging system for hot and cold light sources for eye vision training, characterized in that, include: The light source integration module generates and outputs initial cold light beams and hot light beams. The module incorporates a multi-band semiconductor light-emitting unit, which integrates at least two independently controllable light-emitting chip groups within a single package. Each chip group is connected to an independent constant current drive circuit, receiving pulse width modulation signals from a synchronization control module to linearly adjust the output light intensity in 256 levels. The output of the light source integration module is coupled to the corresponding input ports of the spectral modulation and beam combining modules via polarization-maintaining optical fibers. The spectral modulation and beam combining module performs spectral shaping and spatial beam combining on the input cold and hot light beams to generate a single outgoing temporal composite beam. The digital micromirror array imaging module generates dynamic images based on the training content and modulates the temporal composite beam output by the spectral modulation and beam combining module into a corresponding spatial light distribution, which is then projected onto the trainee's eyes. The synchronization control module, as the timing and logic hub of the system, coordinates the precise synchronization of light source switching, image rendering, and training processes. The synchronization control module includes a field-programmable gate array (FPGA) main controller and connected to it a light source driver interface, a digital micromirror array (DMI) driver interface, and an image data buffer. The synchronization control module is also responsible for running the visual training protocol parser, which dynamically calculates and generates corresponding light source switching sequences and image frame sequences based on the training mode and parameters set by the human-computer interaction module. The human-computer interaction module receives user input and displays the system status; at the same time, the human-computer interaction module also receives and displays the system working status from the synchronization control module in real time, including the current training progress, the light source working mode, and the remaining training time.

2. The eye vision training system with hot and cold light source switching as described in claim 1, characterized in that, The precise synchronization process implemented by the synchronization control module is as follows: The field-programmable gate array main controller has a global timer and a state machine inside; the state machine defines a periodic timing sequence including a cold light period, a hot light period and a transition period according to the loaded training protocol; at the beginning of the cold light period, the state machine triggers the first control event, that is, sends an instruction to the light source driving interface to turn on the driving current of the cold light chipset and turn off the driving current of the hot light chipset at the same time. Two microseconds after the first control event is triggered, the state machine triggers the second control event, which reads the image frame data corresponding to the cold light period from the image data buffer and sends it to the digital micromirror device through the digital micromirror array drive interface. The control flow for the hot light period is symmetrical to that for the cold light period, but the image frame data corresponding to the hot light period is loaded. The transition period is used to achieve a smooth intensity gradient from cold light to hot light or from hot light to cold light. The field-programmable gate array main controller linearly reduces the driving current of the current light source to 0 within 1 millisecond using pulse width modulation technology, while linearly increasing the driving current of the light source for the next cycle from 0 to the target value. During this period, the image content displayed by the digital micromirror device remains unchanged. In the periodic timing defined by the state machine, the duration of the transition period and the light intensity change curve are dynamically adjusted according to the training mode loaded by the training protocol parser.

3. The cold / hot light source switching imaging system for eye vision training according to claim 1, characterized in that: The training protocol parser supports multiple predefined training modes, including alternating flashing mode, gradual fusion mode, and random stimulation mode. In alternating flashing mode, the cold light period and the hot light period alternate in duration, and the switching is completed instantly without a transition period. In gradual fusion mode, each cycle contains a relatively long transition period, so that the light intensity change curve of the cold light and the hot light is sinusoidal. In random stimulation mode, the duration of the cold light period and the hot light period are randomly generated within a preset range. The training protocol parser generates the corresponding timing parameter table in real time and loads it into the state machine according to the selected mode and parameters.

4. The cold / hot light source switching imaging system for eye vision training according to claim 1, characterized in that: The core of the digital micromirror array imaging module is a digital micromirror device, each micromirror measuring 10.8 micrometers in size, with a switching response time of less than 20 microseconds. The digital micromirror device is configured to switch rapidly between two operating states: the first state reflects the incident cold light beam to the projection lens optical path; the second state reflects the incident hot light beam to the same projection lens optical path. The projection lens group converges and corrects the imaging light reflected by the digital micromirror device, ultimately forming a clear, coaxial training image on the eye imaging plane located at the system's exit pupil. The distance between the imaging plane of the digital micromirror array imaging module and the system's exit pupil is precisely designed to be 2 meters at optical infinity to induce a relaxed accommodative state in the trainee's eyes. The projection lens group of the digital micromirror array imaging module adopts an apochromatic design, which includes three lens elements made of anomalously dispersed glass to correct chromatic aberration and spherical aberration in the full wavelength range of 450 nm to 750 nm, ensuring that the spatial positions of the images formed by cold light and hot light are completely superimposed on the retina, with an image plane drift of less than 5 micrometers.

5. The cold / hot light source switching imaging system for eye vision training according to claim 1, characterized in that: The system also integrates an eye-tracking and feedback accommodation subsystem; the eye-tracking and feedback accommodation subsystem includes a near-infrared illumination unit, a high-speed camera, and an image processing coprocessor integrated in the synchronization control module; the near-infrared illumination unit uniformly illuminates the trainee's eye area with invisible light at a wavelength of 850 nanometers. The high-speed camera captures eye-tracking video streams at a frame rate of 200 Hz; the image processing coprocessor runs a pupil center localization algorithm to calculate in real time the deviation of the trainee's gaze point relative to the center position of the training image; when the deviation continues to exceed 3 degrees of visual angle for 500 milliseconds, the image processing coprocessor sends a signal to the synchronization control module, and the synchronization control module then dynamically fine-tunes the display position of the next frame of training image on the digital micromirror array to perform real-time offset compensation; The execution process of the pupil center localization algorithm is as follows: the image processing coprocessor performs Gaussian filtering and noise reduction on each frame of eye movement image; Adaptive threshold segmentation was used to extract the pupil region; the coordinates of the pupil center were calculated using the centroid method.

6. The cold / hot light source switching imaging system for eye vision training according to claim 1, characterized in that: The multi-band semiconductor light-emitting unit integrates at least two independently controllable light-emitting chip groups in a single package. The first light-emitting chip group is configured to emit cold light with a center wavelength in the 450 nm to 495 nm band and a spectral half-width of less than 20 nm. The second light-emitting chip group is configured to emit hot light with a center wavelength in the 620 nm to 750 nm band and a spectral half-width of less than 25 nm. The multi-band semiconductor light-emitting unit integrates three independently controllable light-emitting chip groups in a single package; the third light-emitting chip group is configured to emit green light with a center wavelength of 525 nanometers and a spectral half-width of less than 18 nanometers. The multi-band semiconductor light-emitting unit of the light source integration module adopts flip-chip packaging technology, integrating the cold light-emitting chip and the hot light-emitting chip on the same ceramic substrate, sharing the same heat sink, and the optical center distance between the two light-emitting chips is less than 0.5 mm.

7. The cold / hot light source switching imaging system for eye vision training according to claim 1, characterized in that: The human-computer interaction module includes a touch screen, physical control knobs and buttons, and an embedded microprocessor. The touch screen provides a graphical user interface for selecting training modes and setting training parameters, including single training duration, alternation frequency of hot and cold light, light intensity ratio, and training pattern type. The physical control knobs and buttons fine-tune the projected light intensity in real time. The embedded microprocessor runs the user interface logic and converts the user's settings into protocol instructions, which are then sent to the synchronization control module via a communication bus.

8. The cold / hot light source switching imaging system for eye vision training according to claim 1, characterized in that: The field-programmable gate array (FPGA) main controller has a precise timing logic embedded within it. This timing logic generates two sets of synchronization control signals, with 1 microsecond as the basic time unit. The first set of control signals is a light source switching sequence, which sends instructions to the constant current drive circuit of the light source integrated module according to a preset training protocol, controlling the cold light and hot light chipsets to alternately or mix and light up at specific frequencies, duty cycles, and intensities. The second set of control signals is an image frame synchronization signal, which is strictly phase-locked with the light source switching sequence to ensure that the corresponding image frame data is sent to the digital micromirror array imaging module within 5 microseconds after each light source state switch. The image data buffer stores multiple sets of training pattern sequences, each set containing image content corresponding to the cold light stage and the hot light stage, respectively.

9. The cold / hot light source switching imaging system for eye vision training according to claim 1, characterized in that: The spectral modulation and beam combining module includes a cold light modulation channel, a hot light modulation channel, and a polarization beam splitter beam combiner. The cold light modulation channel consists of a beam collimator, a first bandpass filter, and a first polarization controller arranged sequentially. The beam collimator converts the cold light output from the optical fiber into collimated parallel light. The first bandpass filter further filters out stray light within ±10 nanometers of the center wavelength. The first polarization controller adjusts the polarization state of the cold light beam to S-polarized light. The hot light modulation channel has a structure symmetrical to the cold light modulation channel, including a second beam collimator, a second bandpass filter, and a second polarization controller, ultimately adjusting the polarization state of the hot light beam to P-polarized light. The polarization beam splitter beam combiner is located at the intersection of the output optical paths of the two modulation channels. Its characteristic is that it reflects S-polarized light and transmits P-polarized light. The polarization-controlled cold S-polarized light and hot P-polarized light are spatially superimposed inside the prism, outputting a coaxial and orthogonally polarized temporally composite beam from the same output end. The polarization beam splitter in the spectral modulation and beam combining module is replaced by a three-port polarization beam combining cube, which combines cold S-polarized light, hot P-polarized light and green 45-degree linearly polarized light into a single outgoing composite beam.

10. The cold / hot light source switching imaging system for eye vision training according to claim 1, characterized in that, The field-programmable gate array main controller of the synchronization control module is configured to support independent control of three light sources. Its internal state machine can define a complex cycle including cold light period, hot light period, green light period and multi-light source mixed period. The image data buffer is expanded to store three sets of image frames corresponding to the cold light, hot light and green light stages respectively.

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