Endoscopic imaging system based on illumination and imaging multiplexed waveguide

Abstract

The application discloses an endoscope imaging system based on illumination and imaging multiplexing waveguide and belongs to the medical imaging field.The system realizes the illumination and imaging functions simultaneously through a waveguide with a gradually changing refractive index.In the aspect of illumination, coaxial illumination light sources are introduced into the system through a light splitting prism, and the light sources are coupled into the gradually changing refractive index waveguide through a microscope objective.In the aspect of imaging, reflected light on a target is transmitted into an objective through the gradually changing refractive index waveguide, and then captured by a camera after expansion and beam expansion.The application breaks the aperture limitation caused by the traditional endoscope lens group design method, realizes single waveguide imaging, saves the optical fiber illumination light path, greatly reduces the aperture and heat of the equipment, provides a wide application prospect for hard endoscope imaging surgery, and fills the blank in the related technical field.

Description

TECHNICAL FIELD

[0001] The present invention belongs to the field of medical imaging, and more specifically, it relates to an endoscope imaging system based on illumination and imaging multiplexed waveguide. BACKGROUND

[0002] Endoscope imaging systems play a crucial role in medicine, allowing doctors to observe internal organs and tissues of the human body, providing key information for disease diagnosis and treatment. However, traditional systems often require separate optical fibers for illumination and image transmission, resulting in relatively bulky devices that are not convenient to operate in narrow areas. In addition, the phase difference introduced during light transmission can damage image quality. This limits the application of endoscopes in high-precision diagnosis and observation of complex anatomical structures. The key to solving these problems lies in how to achieve a compact system design while improving image quality and system flexibility. Innovative methods involve integrating illumination and imaging functions into the same waveguide, thereby reducing device size and improving its adaptability in narrow areas. In addition, the introduction of graded-index waveguide technology can optimize the light transmission path, enabling more accurate image acquisition. These innovative methods are expected to promote the further development of endoscope imaging technology, providing more accurate and reliable tools for medical diagnosis and treatment.

[0003] Illumination and imaging multiplexed waveguide technology is an innovative method in the field of endoscope imaging, aiming to overcome the problems existing in traditional endoscope systems. Traditional systems often require separate optical fibers for illumination and image transmission, resulting in complex system design and large size, making it difficult to adapt to narrow areas. Illumination and imaging multiplexed waveguide technology integrates illumination and imaging functions by introducing lenses with graded-index characteristics. However, this technology still faces some challenges. For example, how to achieve accurate focusing and beam expansion of light in lens design to obtain high-quality images is an important problem. By solving these problems, illumination and imaging multiplexed waveguide technology is expected to bring new breakthroughs to the field of endoscope imaging, improve system performance, and promote the development of medical diagnosis and treatment.

[0004] Gradient-index waveguide technology is a key innovation in the field of endoscopic imaging, aiming to address the limitations imposed by traditional optical lens designs. The optical lenses used in conventional endoscopic systems struggle to meet both high-quality illumination and imaging requirements simultaneously. Gradient-index waveguides employ a design where the refractive index gradually changes in space, controlling the bending and focusing of light to achieve superior imaging results. This technology has the potential to eliminate phase differences and reduce image distortion in optical lenses, thereby improving image clarity and accuracy. However, there are challenges in implementing gradient-index waveguide technology. For example, accurately designing and manufacturing gradient-index waveguides to achieve the desired optical performance is a key issue. Additionally, addressing potential material and manufacturing errors during lens production and optimizing lens design under different imaging conditions also require further research. By addressing these issues, gradient-index waveguide technology has the potential to provide higher-quality image acquisition for endoscopic imaging systems, driving further innovation and development in medical imaging technology.

[0005] Splitting prism and objective lens technology is a crucial component in endoscopic imaging systems, used to optimize illumination and image transmission. In traditional endoscopic systems, a splitting prism is often employed to introduce side illumination light sources. Splitting prisms can direct light to the desired direction, enabling side illumination and improving image contrast and clarity. Meanwhile, microscope objectives are used to guide light into gradient-index waveguides for illumination purposes. However, splitting prism and objective lens technology still faces some problems. First, designing and manufacturing efficient splitting prisms to ensure accurate light guidance and distribution is a challenge. Second, the design of objectives needs to consider how to effectively couple light into gradient-index waveguides to achieve high-quality illumination. Additionally, balancing the needs of illumination and imaging to maintain sufficient illumination while achieving high-quality images also requires further research. By addressing these issues, splitting prism and objective lens technology has the potential to enhance the performance of endoscopic imaging systems, improving image clarity and contrast, and providing more accurate and reliable tools for medical diagnosis and treatment.

[0006] Lens coating technology plays an important role in endoscopic imaging systems, aiming to improve lens performance and durability. Traditionally, lens coatings include diamond thin films, anti-reflection films, and hydrophobic films, applied to different surfaces of the lens. Diamond thin films can enhance the lens's scratch resistance, anti-reflection films can improve light transmission, and hydrophobic films can help prevent liquid contamination and fogging. However, lens coating technology still faces some problems. For example, accurately applying and controlling these coatings to ensure their uniformity and stability, as well as optimizing coating design under different optical conditions, still require further research. By addressing these issues, lens coating technology has the potential to improve the durability and imaging quality of endoscopic imaging systems, providing support for the further development of medical imaging technology.

[0007] The technology breaks through the design method of the traditional endoscope system, realizes single waveguide imaging through multiplexing waveguide, avoids the optical fiber illumination light path, and reduces the device size and heat generation. SUMMARY

[0008] In view of the defects of the prior art, the application provides an endoscope imaging system based on illumination and imaging multiplexing waveguide, which realizes the functions of illumination and imaging through a waveguide with a gradient refractive index. In terms of illumination, the side illumination light source is introduced into the system through a light splitting prism, and the light source is coupled into the waveguide with a gradient refractive index by using a microscope objective. In terms of imaging, the reflected light on the target is transmitted to the objective through the waveguide with a gradient refractive index, and then captured by the camera after expansion. In order to ensure the structural strength and imaging performance of the waveguide with a gradient refractive index, the cylindrical surface of the waveguide is coated with a diamond film, and the end surface is coated with an antireflection film and a hydrophobic film. The application breaks through the aperture limitation brought by the traditional endoscope lens design method, realizes single waveguide imaging, avoids the optical fiber illumination light path, greatly reduces the diameter and width of the device and the heat generated by illumination, provides a broad application prospect for hard endoscopic imaging surgery, and fills the gap in the related technical field.

[0009] To achieve the above objectives, the present invention provides an endoscopic imaging system based on an illumination and imaging multiplexed waveguide, comprising: a light source, a polarizer, a beam splitter, an objective lens, a gradient index waveguide, an analyzer, and a camera; the illumination light generated by the light source, after passing through the polarizer, becomes linearly polarized and is then directed into the objective lens through the beam splitter. The objective lens couples the illumination light to the gradient index waveguide, which then transmits the illumination light to the end of the gradient index waveguide near the target, where it is output and illuminates the target; the reflected light generated by the illumination is received by the end of the gradient index waveguide near the target, and an image is transmitted sinusoidally through the gradient index waveguide to the end near the objective lens; after the image is expanded by the objective lens, the imaging beam is projected through the beam splitter, receives light of the desired polarization angle, and is received by the analyzer for imaging by the camera. The unique feature of the system is that the gradient index waveguide employed has the excellent characteristic of low intermodal dispersion. The innovation lies in that the gradient refractive index waveguide used in the present invention exhibits a square index refractive index distribution in its radial structure, which is significantly different from the conventional step-index waveguide. Under this special design, the light meanders in the waveguide, presenting an eye-catching sinusoidal path. After entering from different angles, the light converges after traveling half the pitch length, and continues to follow the sinusoidal path during the journey, and finally focuses at the waveguide outlet to form a clear imaging effect. Compared with traditional step-index cylindrical lenses and conventional optical fibers, this lens waveguide exhibits minimized inter-mode crosstalk, thereby achieving clearer and sharper image imaging, and eliminating the common speckle problem. This innovative waveguide structure will definitely play an important role in endoscopic imaging systems, highlighting its superiority in image quality and resolution, thereby bringing new technical support to the high-level performance of medical imaging technology.

[0010] Preferably, for the endoscope imaging system based on illumination and imaging multiplexing waveguide proposed by the present application, its uniqueness lies in the use of a double-cemented structure of graded-index waveguide to comprehensively consider the aberration control and efficient light collection capability. Generally speaking, the degree of aberration caused by the graded-index waveguide is mainly determined by its pitch number, and the increase of pitch number is positively correlated with the increase of aberration. Therefore, when considering the problem of aberration, the long graded-index waveguide used for transmitting image information needs to ensure a larger pitch value to minimize the introduction of aberration within a certain transmission distance. However, the long-pitch value of the graded-index waveguide means that its numerical aperture is smaller, which will reduce its light collection capability. Therefore, the innovative solution is to cement a short graded-index waveguide with a long graded-index waveguide to fully exert their respective advantages. Specifically, the short graded-index waveguide is designed for light collection, requiring its numerical aperture (NA) not less than 0.6, pitch number not more than 0.500, and length limited within 1 cm. The long graded-index waveguide is then specially used for transmission and reception of reflected imaging targets, with its NA not less than 0.4, pitch number not more than 1.433, and length at least reaching 15 cm. The central refractive index of both is set to 1.666 to ensure the consistency of the system. In addition, in order to minimize the light scattering loss to below 1%, the light scattering of the cemented area is strictly controlled. In summary, through the double-cemented structure of the graded-index waveguide, the endoscope imaging system, while considering the aberration control and efficient light collection capability, provides more innovative support for the progress of medical imaging technology.

[0011] Preferably, for the endoscope imaging system based on illumination and imaging multiplexing waveguide proposed in the present application, its unique feature is that its double-cemented graded-index waveguide has excellent coating protection. For the cylindrical double-cemented graded-index waveguide, due to the lack of mechanical support structure, it is necessary to apply a diamond film on its side to enhance its rigidity and strength, so as to meet the possible collision during the operation. The thickness of this diamond film is about 2-3 μm to ensure the stability and durability of the waveguide. Considering that the double-cemented graded-index waveguide needs to transmit both the illumination light source and the imaging reflected light, the light will pass through the waveguide from two different directions. However, too high reflectivity can affect the resolution of the image, therefore, antireflection coating is applied on both end faces of the waveguide to ensure that the bidirectional reflectivity in the visible light band is less than 2%. Such design helps to optimize the imaging effect and improve the image quality of the system. During use, the waveguide will be inserted into the human body to avoid the blood mist that may appear during the operation from adhering to the end face of the waveguide and affecting the imaging effect. For this purpose, a hydrophobic film is coated on the side of the graded-index waveguide close to the target, thereby effectively reducing the possible liquid adhesion and ensuring the clarity of the imaging result. Through the application of multiple coatings of diamond film, antireflection film and hydrophobic film on the double-cemented graded-index waveguide, the endoscope imaging system of the present application realizes the comprehensive optimization of the strength, imaging quality and durability of the lens, and provides reliable support for the development of medical imaging technology.

[0012] Preferably, for the endoscope imaging system based on illumination and imaging multiplexing waveguide proposed in the present application, its key feature is the use of high-power and small-spot illumination light source. In the system, both the power and the spot size of the light source are important factors. The light source will pass through the beam splitter prism during the incidence and imaging light receiving process, which causes about 50% of the light intensity to be reflected or projected in the direction without effective device each time the beam splitter prism is passed through, and thus the direct light loss reaches as high as 75%. Therefore, in order to ensure sufficient light intensity, a white light source with higher power should be selected, and the spot size should be ensured not to exceed the size of the beam splitter prism. In this context, the light source power usually needs to reach 150-200 W to ensure that the loss in the system optical path does not affect effective imaging. At the same time, in order to maximize the use of light energy, the spot size generated by the light source should be limited within 1 cm x 1 cm. Such design strategy not only ensures the maximization of the optical efficiency of the system, but also helps to provide sufficient light intensity to meet the requirement of sufficient illumination for the endoscope imaging system. Therefore, the high-power and small-spot illumination light source used in the endoscope imaging system, as well as the strict control of the power and spot size of the light source, provides stable and reliable support for ensuring sufficient illumination during imaging.

[0013] Preferably, for the endoscope imaging system based on illumination and imaging multiplexing waveguide proposed by the present application, its unique feature lies in that the embedded microscope objective not only realizes the function of coupling illumination light, but also has the ability of expanding the imaging light beam. In this system, the aperture of the double-cemented graded-index waveguide is about 1 mm, while the spot size is on the order of 1 cm. Therefore, the illumination beam must be focused by the microscope objective to be effectively coupled into the double-cemented graded-index waveguide. Through the microscope objective, the image generated by the double-cemented graded-index waveguide needs to be expanded during transmission, and then focused by the focusing lens of the camera, and finally received by the photosensitive chip. In order to achieve this purpose, the magnification of the microscope objective is set to 20 times, the numerical aperture reaches 0.6, and the working distance is set to 2.04 mm. Such a design strategy makes full use of the optical properties of the microscope objective, which not only meets the precise coupling of illumination light, but also realizes the effective expansion of imaging light, thereby ensuring the clarity and accuracy required in the endoscope imaging process. This unique objective configuration provides key support for the optical performance and imaging quality of the system.

[0014] Preferably, for the endoscope imaging system based on illumination and imaging multiplexing waveguide proposed by the present application, its unique feature lies in that the selected camera is a high-resolution and high-frame-rate color digital camera. The specifications of this camera are designed to provide excellent performance for imaging. Its resolution reaches 3088x2064, and the frame rate can be as high as 60 frames per second. The chip used is Sony IMX 178 row exposure CMOS. In addition, by mounting a 5mm adapter ring lens, the working distance of the camera is set to 96mm, and the field of view size is 32mmx21mm. With this high-resolution and high-frame-rate color digital camera, the endoscope imaging system can acquire and transmit clearer and more detailed images. The combination of its excellent resolution and high frame rate helps to capture subtle anatomical structures and physiological features, thereby supporting doctors to make accurate diagnosis and treatment. In addition, the configuration of Sony IMX 178 chip and 5mm adapter ring lens further ensures the quality and stability of the image, making the imaging result more reliable. In summary, the selection of this color high-resolution and high-frame-rate digital camera provides advanced image acquisition capability for the endoscope imaging system based on illumination and imaging multiplexing waveguide, to support medical professionals to achieve more accurate and reliable imaging results in clinical practice.

[0015] Preferably, for the endoscope imaging system based on illumination and imaging multiplexing waveguide proposed by the present application, it is characterized by adopting polarization imaging technology to reduce the influence of stray light. A linear polarizer is configured in front of the light source and the camera of the endoscope system respectively to achieve effective stray light suppression. The linear polarizer in front of the light source acts as a polarizer, making the illumination light emitted by the light source linearly polarized. The linear polarizer in front of the camera acts as an analyzer for receiving light signals of a specific polarization angle. Through this configuration, the polarizer and the analyzer can effectively reduce the reflected stray light during the propagation of light, and further filter out the interference of stray light by rotating the analyzer. The extinction ratio of these linear polarizers reaches 1000:1, which is suitable for the visible light band with a working wavelength range of 400-700 nm, ensuring that the single transmittance is higher than 70%. With the help of polarization imaging technology, the endoscope imaging system can effectively suppress the interference of reflected stray light, thereby improving the clarity and quality of the image. The polarizer in front of the light source ensures that the illumination light enters the system in a specific polarization state, and the analyzer in front of the camera only receives light signals of the required polarization angle, thereby effectively reducing the influence of interfering light. This innovative design further enhances the performance of the imaging system, providing doctors with more accurate and reliable endoscope images, which helps to improve the effect of clinical diagnosis and treatment.

[0016] Compared with the prior art, the above technical scheme conceived by the present application has the following beneficial effects:

[0017] 1. Integrated illumination and imaging function: By adopting illumination and imaging multiplexing waveguide, the system realizes the integration of illumination and imaging functions, eliminates the independent optical fiber wiring in traditional endoscope systems, greatly reduces the device size, and improves the portability and flexibility of the system.

[0018] 2. High-quality image acquisition: Double-coupled square refractive index waveguide allows for a larger light collection aperture and smaller aberration introduction, further ensuring the clarity and accuracy of the imaging transmission.

[0019] 3. Strong stability endoscope system: The addition of diamond film and anti-reflection film on the waveguide allows the optical waveguide to have higher mechanical strength and light transmission performance, and the presence of the hydrophobic film allows the endoscope system to work stably in the surgical endoscopic environment for a long time.

[0020] 4. Small-caliber invasive imaging: By limiting the waveguide aperture, illumination spot size, and introducing a beam expander, smaller invasive imaging is allowed.

[0021] 5. Multi-modal image acquisition: The application of polarization imaging effectively reduces the influence of stray light, improves the contrast and clarity of the image, and provides doctors with more detailed endoscope image information, which helps more accurate clinical judgment. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a light path schematic diagram of an endoscope imaging system based on illumination and imaging multiplexing waveguide provided by the present application;

[0023] Figure 2 is an optical element structure schematic diagram of an endoscope system provided by the present application. DETAILED DESCRIPTION

[0024] In order to make the objectives, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application in combination with the accompanying drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application. In addition, the technical features involved in each embodiment of the present application described below can be combined with each other as long as they do not conflict with each other.

[0025] The present application provides an endoscope imaging system based on illumination and imaging multiplexing waveguide, comprising: a light source, a polarizer, a light splitting prism, an objective lens, a graded-index waveguide, an analyzer, and a camera. The illumination light generated by the light source has linear polarization after passing through the polarizer, is introduced into the objective lens through the light splitting prism, is coupled into the graded-index waveguide through the objective lens, and is transmitted by the graded-index waveguide to the end of the graded-index waveguide close to the target to output and illuminate the target. The reflected light generated by the illumination is received by the end of the graded-index waveguide close to the target, and the image is transmitted by the graded-index waveguide to the end close to the objective lens in a sinusoidal path. After the image is expanded by the objective lens, the imaging light beam passing through the light splitting prism is received by the analyzer at the required polarization angle, and the light is received by the camera to form an image.

[0026] Further, in the endoscope imaging system based on illumination and imaging multiplexing waveguide provided by the embodiment of the present application, a series of precise methods are adopted in the implementation process to ensure the efficient realization of the function. The key of the system is a long double-cemented graded-index waveguide, which aims to meet the needs of both illumination and imaging. The collimated light source is placed on the side of the system to generate illumination light, which is guided to the built-in microscope objective lens through the light splitting prism. Through this step, the illumination light is coupled into the graded-index waveguide, ensuring the effective transmission of the light. The graded-index waveguide is the key to realizing the dual function. The illumination light is transmitted in the waveguide, gradually moving towards the end close to the target, and generating illumination at that position. At the same time, the target reflection light generated by the illumination is also transmitted in the waveguide, and finally transmitted to the end close to the microscope objective lens. Here, the microscope objective lens plays a key role in effectively expanding the imaging light beam, enabling it to be accurately captured by the camera. After transmission through the waveguide and expansion by the microscope objective lens, the image is received by the camera. Finally, a high-quality imaging pattern is output, providing clear and accurate endoscope imaging.

[0027] Further, the key of the system is to adopt a graded-index waveguide with a square rate refractive index distribution, which is different from the traditional step-index waveguide. The design of this lens waveguide makes the optical fiber travel along a sinusoidal path, and the light rays with different angles of incidence converge after half a pitch length and continue to travel along the sinusoidal path, and finally converge and focus at the focal point at the exit. This unique design can effectively reduce intermodal crosstalk, and compared with the traditional step-index cylindrical lens and ordinary optical fiber, it has smaller speckle phenomenon. In actual operation, by introducing this graded-index structure inside the lens waveguide, the system can make the light transmit in a special way inside the lens waveguide, thereby effectively suppressing the generation of intermodal crosstalk. This design not only can provide clear imaging effect in the endoscope imaging process, but also can reduce the interference of speckle phenomenon in light transmission.

[0028] Further, in the implementation process, the endoscope imaging system of the present application realizes the double-bonding structure of the graded-index waveguide by a fine method to balance aberration control and light collection ability. First, the aberration problem introduced by the graded-index waveguide needs to be considered, and the degree of aberration is related to the pitch number of the graded-index waveguide. In order to reduce the influence of aberration, in the long graded-index waveguide for transmitting image information, it is necessary to ensure that the graded-index waveguide has a longer pitch value, so as to minimize the introduction of aberration within a certain transmission distance. However, it should be noted that the increase of the pitch value will lead to the decrease of the numerical aperture of the graded-index waveguide, thereby affecting the light collection ability. In order to balance the requirements of aberration and light collection ability, the present application adopts a double-bonding structure. Specifically, a short graded-index waveguide with a shorter pitch is bonded with a long graded-index waveguide with a longer pitch. In this way, the short graded-index waveguide is used for light collection, and its numerical aperture (NA) is required to be not less than 0.6, the pitch number is required to be not more than 0.500, and the length is required to be not more than 1 cm; while the long graded-index waveguide is used for transmitting the received target reflection image, and its pitch number is required to be not more than 1.433 and greater than 0.500, and the length is required to be not less than 15 cm. The central refractive index of both is 1.666 to ensure the consistency of light transmission and imaging. In addition, in order to control the scattering loss of light, it is necessary to ensure that the light scattering loss in the bonding area is not more than 1%. Through the design of this double-bonding structure, the endoscope imaging system of the present application can better balance the aberration control and light collection ability in actual application, thereby realizing high-quality endoscopic imaging effect.

[0029] Further, in the actual implementation process, the endoscope imaging system of the present application needs to protect the double-cemented graded-index waveguide. For the columnar double-cemented graded-index waveguide, without mechanical structure support and protection, diamond thin film coating treatment is selected on the side edge to ensure that the rigid strength of the graded-index waveguide is sufficient enough to cope with the collision that may occur during the operation. The thickness of the diamond thin film is set to be in the range of 2 to 3 microns to achieve the desired protection effect. Considering that the double-cemented graded-index waveguide needs to transmit the illumination light source and the imaging reflected light, the light will be reflected twice inside the graded-index waveguide, which may cause the problem of too high reflectivity, thereby affecting the resolution of the image. Therefore, the present application performs antireflection film coating treatment on the two end faces of the graded-index waveguide to ensure that the bidirectional reflectivity of the antireflection film in the visible light band is less than 2%. In this way, not only can the image loss caused by reflection be effectively reduced, but also the high resolution of the image can be maintained. In actual use, the graded-index waveguide will be inserted into the human body for endoscopic operation, in order to prevent blood mist from adhering to the end face of the graded-index waveguide during the operation to affect the imaging effect, the present application performs hydrophobic film coating treatment on the end face of the graded-index waveguide close to the target. This measure can effectively avoid liquid adhesion, maintain the clarity of the surface of the graded-index waveguide, and thus ensure the stability of the imaging effect.

[0030] Further, in the actual implementation process, the endoscope imaging system of the present application ensures that the illumination light source used has sufficient power and appropriate spot size through a series of specific methods. Since the light source incidence and the imaging light reception both pass through the light splitting prism, 50% of the light intensity will be reflected or projected in the direction without effective devices each time through the light splitting prism, thus directly leading to a direct loss of the light source up to 75%. To cope with this loss, a higher power white light source must be used to ensure that the system has sufficient light intensity. In this context, in order to ensure the illumination effect, it is necessary to ensure that the illumination light source has a power of 150 to 200 watts. In addition, in order to adapt to the optical path layout of the system, the effective spot size is also limited to be not greater than the size of the light splitting prism, so as to ensure that the light can be fully utilized and the spot is matched with the optical path.

[0031] Further, in the actual implementation process, the endoscope imaging system of the present application makes full use of the built-in microscope objective lens through a series of specific methods to realize the functions of illumination light coupling and imaging light beam expansion. In the system, the aperture of the double-cemented graded-index waveguide is about 1 mm, and the spot size is on the order of 1 cm. In order to effectively couple the illumination light beam into the double-cemented graded-index waveguide, the microscope objective lens is needed. In the specific steps, the microscope objective lens plays a very key role. It can focus the illumination light beam to ensure that the light is accurately coupled into the double-cemented graded-index waveguide. The image generated by the double-cemented graded-index waveguide needs to be expanded by the microscope objective lens and focused by the camera focusing lens, and finally received by the photosensitive chip. In order to ensure the imaging effect, the characteristics of the microscope objective lens are also carefully designed and selected. Its magnification reaches 20 times, the numerical aperture is 0.6, and the working distance is maintained at 2.04 mm. Through these precise parameter configurations, the system can realize efficient conversion of illumination light and imaging light in actual operation, thereby obtaining clear and accurate imaging results.

[0032] Further, in the actual implementation process, the endoscope imaging system of the present application uses a color high-resolution high-frame-rate digital camera as the camera. First, the resolution of the camera reaches 3088x2064, ensuring the high-definition quality of the image. At the same time, its frame rate is 60 frames per second, which can capture rapidly changing scenes to obtain smooth dynamic imaging. The camera uses a Sony IMX 178 row exposure CMOS chip, which can provide more sensitive image sensing while ensuring imaging quality. In order to further optimize the imaging effect, a 5mm adapter ring is additionally installed on the lens to adjust the optical path. In actual operation, the working distance of the camera is controlled at 96 mm to ensure that the image of the target area can be accurately captured. At the same time, the field of view range is 32mmx21mm, which can fully cover the area of interest to ensure that no key information is missed.

[0033] Further, in the implementation of the endoscopic imaging system of the present application, a polarization imaging technique is employed to reduce the interference of stray light. In the endoscopic system, a linear polarizer is configured at the front end of the light source and the camera, which plays a key role in actual operation. First, the linear polarizer at the front end of the light source is designed as a polarizer, which ensures that the illumination light emitted from the light source has specific linear polarization properties. While the linear polarizer at the front end of the camera acts as an analyzer, which is used to receive and filter light signals of specific polarization angles. Through this configuration, the polarizer and the analyzer can play an important role in the propagation of light signals, effectively reducing the interference of reflected stray light. By controlling the polarization angle of the polarizer and the analyzer, precise control of the light signal can be achieved, thereby filtering out stray light to the greatest extent. It is worth noting that the performance of the polarizer used has also been carefully selected and configured. The extinction ratio of the polarizer is 1000:1, which ensures that the transmission of light signals in the unwanted polarization direction is almost completely suppressed. In addition, the single transmittance of the polarizer in the visible light band is also controlled to be ≥70%, which ensures that enough light signals can be transmitted to the camera for imaging.

[0034] The following is described in conjunction with specific embodiments and the accompanying drawings.

[0035] As Figure 1 shown is a light path schematic diagram in an endoscopic imaging system based on illumination and imaging multiplexing waveguide provided by the present application. Unlike traditional RodLens rigid endoscopes, the present application realizes the simultaneous completion of illumination and imaging using a lens group. First, for the illumination path, the illumination light is generated by the collimated light source at the side of the system, and after passing through the polarizer, it is introduced into the built-in microscope objective through the beam splitter prism. The illumination light is coupled to the graded-index waveguide by the objective, and the illumination light is transmitted to the end of the graded-index waveguide near the target by the graded-index waveguide and illuminates the object target. For the imaging path, the reflected light generated by the illumination is received by the end of the graded-index waveguide near the target, and the image is transmitted to the end near the microscope objective through the curved path. After the beam expansion of the microscope objective, the image enters the analyzer through BS refraction, removes most of the stray light, and is finally received by the camera.

[0036] As Figure 2As shown, the endoscope optical element structure schematic diagram provided by the application, short graded refractive index waveguide 1 is used for light collection, and the requirements are NA≥0.6, pitch number≤0.500, and length≤1cm. Long graded refractive index waveguide 2 is used for transmitting the target reflection image received, and the requirements are pitch number≤1.433, length≥15cm; the center refractive index of both is 1.666, and the control glue area light scattering loss is≤1%. The high polymer adhesive material 3 bonds the short waveguide and the long waveguide to form a columnar graded refractive index waveguide group. The cylindrical high polymer carbon fiber material 4 is wrapped outside the graded refractive index waveguide, improves the compression resistance of the graded refractive index waveguide, and maintains the basic shape of the graded refractive index waveguide. The microscope objective 5 realizes the convergence of light, the magnification is 20x, the numerical aperture is 0.6, and the working distance is 2.04mm. The light splitting prism 6 makes 50% of the input light reflected, and the other 50% transmitted. The polaroid 7 includes a polarizer and an analyzer, the extinction ratio is 1000:1, the working wavelength is 400-700nm, the single pass rate in the visible light band is≥70%, and the combination of the two can eliminate most stray light. The camera 8 is a color high-resolution high-frame-rate digital camera. The resolution is 3088x2064, the frame rate is 60fps, the chip is Sony IMX 178 row exposure CMOS, the lens is added with a 5mm ring, the working distance is 96mm, and the field of view is 32mmx21mm. The light source 9 is a high-power white light source, and the effective spot size is not greater than the size of the light splitting prism. The light source power is 150-200W, and the spot size is≤1cmx1cm.

[0037] The application is not limited to the above specific embodiments, and those skilled in the art can use other various specific embodiments to implement the application according to the disclosed content of the application, therefore, any design using the design structure and idea of the application, and making some simple changes or modifications, falls within the protection scope of the application.

Claims

1. An endoscopic imaging system based on an illumination and imaging multiplexing waveguide, characterized in that: include: A light source, a polarizer, a beam splitter, an objective lens, a gradient refractive index waveguide, an analyzer, and a camera; the gradient refractive index waveguide has a square refractive index distribution in the radial direction, the refractive index remains unchanged in the axial direction, and the paraxial meridional imaging light propagates along a sinusoidal path; the gradient refractive index waveguide comprises a first gradient refractive index waveguide and a second gradient refractive index waveguide of a double-glued structure, wherein the first gradient refractive index waveguide is located at one end close to the target; the first gradient refractive index waveguide is used for receiving light, with an NA ≥ 0.6, a pitch number ≤ 0.500, and a length ≤ 1 cm; the second gradient refractive index waveguide is used for transmitting the received target reflection imaging, with an NA ≥ 0.4, a pitch number 0.500 < ≤ 1 .433, length ≥15cm; the central refractive index of both is 1.666, and the light scattering loss in the bonding area is ≤1%; the illumination light generated by the light source has linear polarization after passing through the polarizer, and is introduced into the objective lens through the beam splitter prism, and the illumination light is coupled to the gradient refractive index waveguide through the objective lens, and the gradient refractive index waveguide transmits the illumination light to the end of the gradient refractive index waveguide close to the target for output and illumination of the target, and the reflected light generated by the illumination is received by the end of the gradient refractive index waveguide close to the target, and the reflected light is transmitted to the end close to the objective lens through the gradient refractive index waveguide, and after being expanded by the objective lens, it is projected onto the beam splitter prism, received by the analyzer, and finally imaged at the camera.

2. The endoscopic imaging system based on the illumination and imaging multiplexing waveguide according to claim 1, characterized in that: The cylindrical outer surface of the gradient refractive index waveguide is coated with a diamond film with a thickness of 2 to 3 μm; the two end faces of the gradient refractive index waveguide are coated with an anti-reflection film in the visible light band, and the bidirectional reflectivity is less than 2%.

3. The endoscopic imaging system based on the illumination and imaging multiplexing waveguide according to claim 2, characterized in that: A hydrophobic film is plated on the antireflection film.

4. The endoscopic imaging system based on illumination and imaging multiplexing waveguide according to claim 1, characterized in that: The spot size of the light source is no larger than 2 / 3 of the size of the beam splitter prism; the light source power is 150-200W, and the spot size is ≤1cm×1cm.

5. The endoscopic imaging system based on illumination and imaging multiplexing waveguide according to claim 1, characterized in that: The objective lens has a magnification of 20×, a numerical aperture of 0.6, and a working distance of 2.04 mm.

6. The endoscopic imaging system based on illumination and imaging multiplexing waveguide according to claim 1, characterized in that: The camera has a resolution of 3088×2064, a frame rate of 60fps, a Sony IMX 178-line exposure CMOS chip, a lens with a 5mm adapter, a working distance of 96mm, and a field of view of 32mm×21mm.

7. The endoscopic imaging system based on illumination and imaging multiplexing waveguide according to claim 1, characterized in that: The extinction ratio of the polarizer and analyzer is not less than 1000:1, the operating wavelength is 400~700nm, and the single transmittance in the visible light band is ≥70%.

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