Optical system of color three-dimensional fundus imager

Abstract

The invention belongs to the technical field of retina imaging and fundus three-dimensional reconstruction, and particularly relates to a color three-dimensional fundus imager optical system. Comprising a large eye objective lens, a dichroscope, a hollow reflector, a focusing lens, a spectroscope, a retina lens, a retina imaging chip, a fixation lens, a sighting mark lamp, an illumination lens, an annular light source, a pupil lens, a pupil imaging chip, an infrared lens, an infrared dodging lens, an infrared light source, a scanning lens, a three-dimensional galvanometer, a collimator, a coupler, a frequency sweeping light source and a dispersion compensator. A polarization controller, a coupler and a photoelectric detector. The system is mainly composed of a visible light imaging light path, an infrared imaging light path and a laser imaging light path, the visible light imaging light path is used for shooting color fundus two-dimensional images, the infrared imaging light path is used for real-time positioning and focusing of human eye pupils, and the laser imaging light path is used for three-dimensional tomography of retinas. The objective of the invention is to solve the problem that existing medical equipment cannot acquire fundus color three-dimensional images.

Description

Technical Field

[0001] The invention belongs to the technical field of retinal imaging and fundus three-dimensional reconstruction, and in particular relates to a color three-dimensional fundus imager optical system. Background Art

[0002] Vision is the most important way for humans to obtain external information. About 80% of perception comes from the eyes, so the study of the human eye is very important. The physiological structure of the human eye is complex, including the cornea, pupil, iris, lens and retina. The retina is the only physiological tissue in the human body that can be directly observed non-invasively. Examination of the retina can accurately determine a variety of eye diseases and systemic diseases. Through detailed observation of the retina with imaging technology, the key parameters of the biological tissue of the human eye can be obtained, which is of great significance for the prevention and diagnosis of ophthalmology and related diseases.

[0003] At present, the fundus imaging technologies commonly used in clinical practice mainly include ophthalmoscopes, fundus cameras, laser scanning ophthalmoscopes and optical coherence tomography (OCT). Ophthalmoscopes and fundus cameras are based on visible light imaging and can generate color images; laser scanning ophthalmoscopes and OCT use laser scanning imaging to generate grayscale images. As the most commonly used equipment in fundus lesion examinations, fundus cameras can provide color, wide-angle retinal images, intuitively presenting the overall structure of the retina, the direction of blood vessels, and the location of lesions, such as macular edema, hemorrhage, exudation, and retinal detachment. However, fundus cameras have low sensitivity to subtle structural changes, and the two-dimensional images they generate cannot present the spatial relationship of the three-dimensional retinal structure, which brings certain limitations to doctors' diagnosis. In contrast, OCT is widely used in retinal imaging due to its advantages of high resolution and non-destructive testing. It can provide high-resolution cross-sectional images, showing in detail the layered structure and subtle changes of the retina, such as thinning of the nerve fiber layer, macular edema, retinal tears, and vitreous traction. However, the grayscale tomographic images generated by OCT cannot reflect the true color distribution of the retina, making it difficult to evaluate the overall fundus.

[0004] In the actual clinical diagnosis and treatment process, relying solely on a single modality of data to assist diagnosis has limitations and cannot achieve good results. Doctors often need to collect multiple imaging data for joint examination. The combined application of fundus cameras and OCT has played an important role in the early diagnosis and monitoring of diseases such as diabetic retinopathy, glaucoma, macular degeneration and retinal vein occlusion, effectively reducing the risk of missed diagnosis and misdiagnosis, and can obtain a more comprehensive and accurate evaluation of fundus diseases. However, this joint examination also has many problems: First, fundus photography and OCT are two independent medical devices, and patients need to move and adjust their positions many times, which is not only time-consuming, but may also cause discomfort to patients, especially the elderly and patients with limited mobility. Long examination time and complex procedures may reduce the degree of patient cooperation, especially in the case of limited medical resources, and may also affect the quality of the examination. Secondly, the two devices are operated separately, requiring medical staff to repeatedly adjust the instruments and parameters, increase the operation steps, and coordinate the data generated by different devices. The two devices may also use different image standards or imaging areas that are not completely consistent, making it difficult to directly compare or integrate the two data during diagnosis, increasing the possibility of misdiagnosis or missed diagnosis. Finally, the purchase, maintenance and calibration costs of independent devices are high, and training medical staff to master the operation of both devices also requires additional resources, which undoubtedly increases the burden on medical institutions. Summary of the invention

[0005] The purpose of the present invention is to provide an optical system integrating multiple imaging modalities to achieve three-dimensional true color stereoscopic imaging of the human eye retina.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is as follows:

[0007] The color three-dimensional fundus imager optical system integrates the fundus camera and OCT into one, and is mainly composed of three optical paths: visible light imaging optical path, laser imaging optical path and infrared imaging optical path. Each optical path has its own specific working band, and a coaxial design is used to integrate the three optical paths without affecting each other.

[0008] The optical system of the color three-dimensional fundus imager includes a large eyepiece objective lens, a first dichroic mirror, a second dichroic mirror, a scanning lens, a three-dimensional galvanometer and a collimator are arranged in sequence on the right side of the large eyepiece objective lens, a hollow reflector, a focusing lens, a first beam splitter, a retinal lens and a retinal imaging chip are arranged in sequence below the first dichroic mirror, an illumination lens and a ring light source are arranged in sequence on the right side of the hollow reflector, a fixation lens and a sight mark light are arranged in sequence on the right side of the first beam splitter, a second beam splitter, a pupil lens and a pupil imaging chip are arranged in sequence above the second dichroic mirror, and an infrared lens, an infrared uniform light lens and an infrared light source are arranged in sequence on the right side of the second beam splitter.

[0009] Furthermore, it also includes a swept-frequency light source, a first coupler, a dispersion compensator, a polarization controller, a second coupler and a photodetector, one end of the collimator is connected to the first end of the first coupler through an optical fiber, the second end of the first coupler is respectively connected to the swept-frequency light source and the first end of the dispersion compensator through optical fibers, the second end of the dispersion compensator is connected to the first end of the polarization controller through optical fibers, the second end of the polarization controller is connected to the first end of the second coupler through optical fibers, the first end of the first coupler is also connected to the first end of the second coupler through optical fibers, and the second end of the second coupler is respectively connected to the first end and the second end of the photodetector.

[0010] Furthermore, the pupil of the human eye is located at the front focal plane of the eyepiece large objective lens, the first dichroic mirror is located at the rear focal plane of the eyepiece large objective lens, and the rear focal plane of the eyepiece large objective lens coincides with the front focal planes of the scanning lens, the focusing lens, the pupil lens, the illumination lens, and the infrared lens.

[0011] Furthermore, the eyepiece large objective lens, the first dichroic mirror, the hollow reflector, the focusing lens, the first beam splitter, the retinal lens, the retinal imaging chip, the fixation lens, the sight mark light, the illumination lens and the annular light source constitute a visible light imaging optical path, which is recorded as an A optical path.

[0012] Furthermore, the eyepiece large objective lens, the first dichroic mirror, the second dichroic mirror, the second beam splitter, the pupil lens, the pupil imaging chip, the infrared lens, the infrared homogenizing lens and the infrared light source constitute an infrared imaging optical path, which is recorded as the B optical path.

[0013] Furthermore, the eyepiece objective, the first dichroic mirror, the second dichroic mirror, the scanning lens, the three-dimensional galvanometer, the collimator, the first coupler, the swept light source, the dispersion compensator, the polarization controller, the second coupler and the photodetector constitute a laser imaging optical path, which is recorded as the C optical path.

[0014] Furthermore, in the A optical path, the large eyepiece objective, the first dichroic mirror, the hollow reflector, the focusing lens, the first beam splitter, the retinal lens and the retinal imaging chip constitute the fundus imaging optical path, recorded as the A1 sub-optical path; the large eyepiece objective, the first dichroic mirror, the hollow reflector, the illumination lens and the annular light source constitute the fundus illumination optical path, recorded as the sub-optical path; the large eyepiece objective, the first dichroic mirror, the hollow reflector, the focusing lens, the first beam splitter, the fixation lens and the sight mark light constitute the fixation light path, recorded as the A3 sub-optical path.

[0015] Furthermore, in the B optical path, the large eyepiece objective, the first dichroic mirror, the second dichroic mirror, the second beam splitter, the pupil lens and the pupil imaging chip constitute the pupil imaging optical path, which is recorded as the B1 sub-optical path; the large eyepiece objective, the first dichroic mirror, the second dichroic mirror, the second beam splitter, the infrared lens, the infrared homogenizing lens and the infrared light source constitute the pupil illumination optical path, which is recorded as the B2 sub-optical path.

[0016] Furthermore, in the C optical path, the eyepiece objective, the first dichroic mirror, the second dichroic mirror, the scanning lens, the three-dimensional galvanometer and the collimator constitute the spatial optical path portion of the C optical path, which is recorded as the C1 sub-optical path; the collimator, the first coupler, the swept light source, the dispersion compensator, the polarization controller, the second coupler and the photodetector constitute the fiber optic path portion of the C optical path, which is recorded as the C2 sub-optical path.

[0017] Furthermore, the hollow reflector reflects the visible light emitted by the annular light source in the A2 sub-optical path, the green light emitted by the sight mark lamp in the A3 sub-optical path, and the fundus return light required by the retinal imaging chip in the A1 sub-optical path.

[0018] Furthermore, the A1 sub-optical path and the A3 sub-optical path share a focusing lens, and the focusing lens can be mechanically moved back and forth in the middle area between the hollow reflector and the first beam splitter.

[0019] Furthermore, the retinal imaging chip is located at the rear focal plane of the retinal lens, and the retinal imaging chip is a CCD or CMOS in the visible light band; the sight mark light is located at the rear focal plane of the fixation lens, and the sight mark light is an LED display screen; the annular light source is located at the rear focal plane of the illumination lens, and the annular light source is an annular illumination light source, which is composed of red, green and blue three-color LED lights arranged in an orderly manner.

[0020] Furthermore, the second beam splitter reflects the infrared light emitted by the infrared light source to the surface of the pupil of the human eye, and returns the light to the pupil imaging chip through the pupil surface.

[0021] Furthermore, the infrared light source is located at the rear focal plane of the infrared uniform light lens, the infrared light source is a planar LED lighting source, and is composed of near-infrared LED lamps arranged in an orderly manner. The pupil imaging chip is located at the rear focal plane of the pupil lens, and the pupil imaging chip is a CCD or CMOS in the infrared light band.

[0022] Furthermore, the collimator can convert the laser emitted by the swept-frequency light source into a spatial parallel light beam in the C1 sub-optical path, and can also couple the fundus return light in the C1 sub-optical path to the optical fiber in the C2 sub-optical path. The C1 sub-optical path and the C2 sub-optical path perform mutual conversion between spatial light beams and optical fiber light beams through the collimator.

[0023] Furthermore, the laser emitted by the swept-frequency light source is divided into two beams by a first coupler, one beam is transmitted to a collimator via an optical fiber, and the other beam is transmitted to a second coupler via an optical fiber. The first coupler can receive fundus return light from the collimator and transmit the fundus return light to a dispersion compensator.

[0024] Furthermore, the dispersion compensation device can receive the fundus return light transmitted by the first coupler and transmit the fundus return light to the polarization controller. The dispersion compensator is a combination of optical fiber filaments of specific length and glass blocks of specific material, which can compensate for the group dispersion of the optical system and match the optical path difference.

[0025] Furthermore, the second coupler is a 5:5 fiber coupler, and the reference laser emitted by the swept-frequency light source interferes with the fundus return light emitted from the polarization controller in the second coupler. The interfered light beam is received by the photodetector and converted into an electrical signal required for imaging. The photodetector is a balanced detector.

[0026] Furthermore, the frequency-sweeping light source is a frequency-sweeping laser with a wavelength range of 1000nm to 1200nm; the polarization controller is a three-ring polarization controller that can change the polarization state of the light beam.

[0027] The working method of the optical system of the color three-dimensional fundus imager comprises the following steps:

[0028] S1: Complete the work of eye positioning and focusing;

[0029] S2: A optical path fixes the human eye and generates a retinal guidance image;

[0030] S3: Realize color two-dimensional imaging and three-dimensional tomographic imaging of the fundus.

[0031] Furthermore, step S1 is specifically as follows:

[0032] The B optical path starts working first. The infrared light source emits infrared light and illuminates the pupil of the human eye through the B2 sub-optical path. Then the infrared return light of the human eye pupil is imaged on the pupil imaging chip through the B1 sub-optical path. The main function of the B optical path is to locate and focus the human eye. By real-time monitoring of the center position of the pupil and the clarity of the pupil image, it can ensure that the center of the human eye pupil is aligned with the optical axis of the optical system and lock the human eye pupil at the front focal plane of the large objective lens.

[0033] Furthermore, step S2 is specifically as follows:

[0034] After completing the work of eye positioning and focusing, the A optical path starts to work. First, the sight mark lamp transmits the fixation pattern to the human eye retina through the A3 sub-optical path to guide the human eye to fixate. Then the ring light source transmits visible light through the A2 sub-optical path to illuminate the human eye retina, and the return light from the human eye retina is imaged on the retinal imaging chip through the A1 sub-optical path. The main functions of the A optical path are fundus color imaging and human eye fixation. The A3 sub-optical path is in working state during the operation of the entire optical system to ensure that the human eye always fixes relative to the optical system. Before the C optical path scans and images, the ring light source emits monochromatic weak light, and a black and white retinal guide image is formed on the retinal imaging chip.

[0035] Furthermore, step S3 is specifically as follows:

[0036] After the A optical path generates the retinal guide image, the C optical path starts to work: first, the deflection angle of the three-dimensional galvanometer in the C optical path is reset to zero, and the laser scanning area is set on the fundus according to the retinal guide image generated by the A optical path; then the swept frequency light source of the C optical path emits laser, and sends the laser to the three-dimensional galvanometer in the C1 sub-optical path through the C2 sub-optical path, and the three-dimensional galvanometer deflects the galvanometer to complete the tomographic imaging of the laser in the set area of ​​the fundus; when the C optical path completes the scanning imaging, the annular light source in the A optical path emits three-color strong light to realize color two-dimensional imaging of the fundus.

[0037] Preferably, the operating wavelength of the A optical path is 400nm to 760nm, the operating wavelength of the B optical path is 800nm ​​to 890nm, and the operating wavelength of the C optical path is 900nm to 1200nm. Such a design can ensure that the optical paths do not affect each other while reducing the system volume and improving the stability of the system. In fact, the operating wavelength range of each optical path can also be appropriately expanded or reduced according to actual needs.

[0038] Preferably, the large objective lens for receiving the eye is coated with an anti-reflection film in the wavelength range of 400nm to 1200nm, the first dichroic mirror is set to transmit infrared light in the wavelength range of 800nm ​​to 1200nm, and reflect visible light in the wavelength range of 400nm to 760nm, and the second dichroic mirror is set to transmit infrared light in the wavelength range of 900nm to 1200nm, and reflect infrared light in the wavelength range of 800nm ​​to 890nm. Such a design can effectively ensure that the imaging of each optical path does not affect each other. In fact, the working bands of the first dichroic mirror and the second dichroic mirror and the coating range of the large objective lens for receiving the eye can also be specifically considered according to actual needs.

[0039] The color three-dimensional fundus imaging optical system of the present invention integrates the fundus camera and OCT into one, and has the following beneficial effects compared with the prior art:

[0040] 1. Improve examination efficiency. Existing fundus cameras and OCT are usually independent devices, and patients need to move between different devices during examination, which affects the examination process. The present invention can complete fundus photography and OCT scanning at one time, reducing examination time, improving patient comfort and medical efficiency.

[0041] 2. Improve diagnostic accuracy. Fundus cameras provide two-dimensional color retinal images, while OCT provides three-dimensional high-resolution tomographic images. Combining the two can provide more comprehensive retinal structural information, improve the accuracy of disease diagnosis, and facilitate doctors to quickly compare and analyze lesions.

[0042] 3. Improve imaging accuracy. Since the fundus camera and OCT in the present invention are in the same optical system, the focus and alignment can be automatically adjusted through algorithms, which improves the imaging quality and avoids imaging errors caused by position differences in traditional equipment; since the fundus camera and OCT data come from the same source, more accurate image registration can be performed, making it easier for doctors to conduct longitudinal analysis and disease monitoring of the same patient.

[0043] 4. The all-in-one machine integrates fundus photography and OCT. Patients can complete multiple examinations in just one visit. The optimization of the examination process and the shortening of the examination time can improve the patient's medical experience, especially for the elderly or patients with limited mobility, which can effectively improve medical efficiency. The all-in-one machine can simultaneously complete imaging in different modes, ensure the spatial position consistency of fundus photography and OCT data, and integrate multiple imaging results to generate true color three-dimensional images, reducing the time for doctors to analyze data from multiple devices, helping to make diagnoses faster and providing doctors with more accurate diagnostic basis. At the same time, the integrated equipment reduces the need for multiple independent devices, reduces acquisition and maintenance costs, takes up less space, and optimizes the utilization of medical resources.

[0044] 5. The all-in-one machine is mainly composed of three optical paths: visible light imaging optical path, laser imaging optical path and infrared imaging optical path. Each optical path has its own specific working band, and the coaxial design is used to integrate the three optical paths without affecting each other, which can significantly improve the inspection accuracy and efficiency.

[0045] Compared with the existing technology, the present invention has significant improvements in examination efficiency, diagnostic accuracy, patient experience, equipment cost, optical alignment and data synchronization. It is suitable for medical institutions, physical examination centers, remote diagnosis and treatment and primary medical markets, and has higher clinical value and market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present invention can be further illustrated by the non-limiting examples given in the accompanying drawings;

[0047] Figure 1 A schematic diagram of the optical structure of an optical system embodiment of a color three-dimensional fundus imager of the present invention;

[0048] Figure 2 A schematic diagram of light splitting in an optical system embodiment of a color three-dimensional fundus imager of the present invention;

[0049] Figure 3 Schematic diagram of the optical path of visible light imaging in an embodiment of the optical system of the color three-dimensional fundus imager of the present invention;

[0050] Figure 4 It is a schematic diagram of the infrared imaging optical path in the embodiment of the optical system of the color three-dimensional fundus imager of the present invention;

[0051] Figure 5 Schematic diagram of the laser imaging optical path in the embodiment of the optical system of the color three-dimensional fundus imager of the present invention;

[0052] The symbols in the diagram are explained as follows:

[0053] Eyepiece large objective lens abc1, first dichroic mirror abc2, hollow reflector a1, focusing lens a2, first beam splitter a3, retinal lens a4, retinal imaging chip a5, fixation lens a6, sight mark light a7, illumination lens a8, annular light source a9, second dichroic mirror bc1, second beam splitter b1, pupil lens b2, pupil imaging chip b3, infrared lens b4, infrared uniform light lens b5, infrared light source b6, scanning lens c5, three-dimensional galvanometer c4, collimator c3, first coupler c2, frequency sweeping light source c1, dispersion compensator c6, polarization controller c7, second coupler c8, photodetector c9, visible light imaging optical path A, infrared imaging optical path B and laser imaging optical path C. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the present invention, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0055] Example 1

[0056] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5As shown, the optical system of the color three-dimensional fundus imager of the present invention comprises a large eyepiece objective lens abc1, a first dichroic mirror abc2, a second dichroic mirror bc1, a scanning lens c5, a three-dimensional galvanometer c4 and a collimator c3 are sequentially arranged on the right side of the large eyepiece objective lens abc1, a hollow reflector a1, a focusing lens a2, a first beam splitter a3, a retinal lens a4 and a retinal imaging chip a5 are sequentially arranged below the first dichroic mirror abc2, an illumination lens a8 and a ring light source a9 are sequentially arranged on the right side of the hollow reflector a1, a fixation lens a6 and a sight mark lamp a7 are sequentially arranged on the right side of the first beam splitter a3, a second beam splitter b1, a pupil lens b2 and a pupil imaging chip b3 are sequentially arranged above the second dichroic mirror bc1, and a right side of the second beam splitter b1 is provided. An infrared lens b4, an infrared homogenizing lens b5, and an infrared light source b6 are sequentially arranged on the side; it also includes a swept-frequency light source c1, a first coupler c2, a dispersion compensator c6, a polarization controller c7, a second coupler c8, and a photodetector c9. One end of the collimator c3 is connected to the first end of the first coupler c2 through an optical fiber, the second end of c2 is respectively connected to the swept-frequency light source c1 and the first end of the dispersion compensator c6 through optical fibers, the second end of the dispersion compensator c6 is connected to the first end of the polarization controller c7 through optical fibers, the second end of the polarization controller c7 is connected to the first end of the second coupler c8 through optical fibers, the first end of c2 is also connected to the first end of the second coupler c8 through optical fibers, and the second end of the second coupler c8 is respectively connected to the first end and the second end of the photodetector c9.

[0057] Preferably, the pupil of the human eye is located at the front focal plane of the large objective lens abc1, and the first dichroic mirror abc2 is located at the rear focal plane of the large objective lens abc1. The rear focal plane of the large objective lens abc1 coincides with the front focal plane of the scanning lens c5, the front focal plane of the focusing lens a2, the front focal plane of the pupil lens b2, the front focal plane of the illumination lens a8, and the front focal plane of the infrared lens b4. Such a design can not only ensure the object-image conjugate relationship between the pupil of the human eye and the annular light source a9, the pupil imaging chip b3, and the three-dimensional galvanometer c4, but also ensure the object-image conjugate relationship between the fundus and the retinal imaging chip a5 and the sight mark light a7. In fact, the specific positional relationship between the large objective lens abc1 and other lenses can also be specifically considered according to actual needs.

[0058] The large objective lens abc1, the first dichroic mirror abc2, the hollow reflector a1, the focusing lens a2, the first beam splitter a3, the retinal lens a4, the retinal imaging chip a5, the fixation lens a6, the sight mark light a7, the illumination lens a8 and the annular light source a9 form a visible light imaging optical path, which is recorded as the A optical path.

[0059] The large objective lens abc1, the first dichroic mirror abc2, the second dichroic mirror bc1, the second beam splitter b1, the pupil lens b2, the pupil imaging chip b3, the infrared lens b4, the infrared uniform light lens b5 and the infrared light source b6 form an infrared imaging optical path, which is recorded as the B optical path.

[0060] The large objective lens abc1, the first dichroic mirror abc2, the second dichroic mirror bc1, the scanning lens c5, the three-dimensional galvanometer c4, the collimator c3, the first coupler c2, the swept light source c1, the dispersion compensator c6, the polarization controller c7, the second coupler c8 and the photodetector c9 constitute a laser imaging optical path, which is recorded as C optical path.

[0061] In the A optical path, the large eyepiece objective lens abc1, the first dichroic mirror abc2, the hollow reflector a1, the focusing lens a2, the first beam splitter a3, the retinal lens a4 and the retinal imaging chip a5 constitute the fundus imaging optical path, which is recorded as the A1 sub-optical path; the large eyepiece objective lens abc1, the first dichroic mirror abc2, the hollow reflector a1, the illumination lens a8 and the annular light source a9 constitute the fundus illumination optical path, which is recorded as the A2 sub-optical path; the large eyepiece objective lens abc1, the first dichroic mirror abc2, the hollow reflector a1, the focusing lens a2, the first beam splitter a3, the fixation lens a6 and the sight mark light a7 constitute the fixation light path, which is recorded as the A3 sub-optical path.

[0062] In the B optical path, the large eyepiece objective lens abc1, the first dichroic mirror abc2, the second dichroic mirror bc1, the second beam splitter b1, the pupil lens b2 and the pupil imaging chip b3 constitute the pupil imaging optical path, which is recorded as the B1 sub-optical path; the large eyepiece objective lens abc1, the first dichroic mirror abc2, the second dichroic mirror bc1, the second beam splitter b1, the infrared lens b4, the infrared uniform light lens b5 and the infrared light source b6 constitute the pupil illumination optical path, which is recorded as the B2 sub-optical path.

[0063] In the C optical path, the large objective lens abc1, the first dichroic mirror abc2, the second dichroic mirror bc1, the scanning lens c5, the three-dimensional galvanometer c4 and the collimator c3 constitute the spatial optical path part of the C optical path, which is recorded as the C1 sub-optical path; the collimator c3, the first coupler c2, the swept light source c1, the dispersion compensator c6, the polarization controller c7, the second coupler c8 and the photodetector c9 constitute the fiber optic path part of the C optical path, which is recorded as the C2 sub-optical path.

[0064] Preferably, the hollow reflector a1 reflects the visible light emitted by the annular light source a9 in the A2 sub-optical path, the green light emitted by the sight mark light a7 in the A3 sub-optical path, and the fundus return light required by the retinal imaging chip a5 in the A1 sub-optical path. Such a design can ensure that the illumination light enters the human eye in the form of an annular light spot, avoids the illumination light beam passing through the high-reflection area in the center of the cornea, and increases the light flux of the fundus return light, which is conducive to clear imaging of the retinal imaging chip a5. In fact, the type of hollow reflector a1 can also be specifically considered according to actual conditions.

[0065] Preferably, the A1 sub-optical path and the A3 sub-optical path share a focusing lens a2, and the focusing lens a2 can be mechanically moved forward and backward in the middle area between the hollow reflector a1 and the first beam splitter a3 to achieve clear imaging of the sight mark light a7 on the fundus and clear imaging of the fundus return light on the retinal imaging chip a5. Such a design can reduce hardware costs and simplify system complexity. In fact, the focusing method of the focusing lens a2 can also be specifically considered according to actual conditions.

[0066] Preferably, the retinal imaging chip a5 is located at the rear focal plane of the retinal lens a4, and the retinal imaging chip a5 is a CCD or CMOS in the visible light band; the sight mark light a7 is located at the rear focal plane of the fixation lens a6, and the sight mark light a7 is an LED display screen that can display various green fixation patterns; the annular light source a9 is located at the rear focal plane of the illumination lens a8, and the annular light source a9 is an annular illumination light source, which is composed of red, green and blue LED lights arranged in an orderly manner. Such a design is conducive to multi-band imaging. In fact, the types of the retinal imaging chip a5, the sight mark light a7 and the annular light source a9 can also be specifically considered according to actual conditions.

[0067] Preferably, the second beam splitter b1 reflects the infrared light emitted by the infrared light source b6 to the surface of the pupil of the human eye, and returns the light to the pupil imaging chip b3 through the pupil surface. Such a design can reduce the volume of the optical system and improve the imaging stability. In fact, the type of the second beam splitter b1 can also be specifically considered according to actual conditions.

[0068] Preferably, the infrared light source b6 is located at the rear focal plane of the infrared homogenizing lens b5, and the infrared light source b6 is a planar LED lighting source, which is composed of near-infrared LED lamps arranged in an orderly manner, and the pupil imaging chip b3 is located at the rear focal plane of the pupil lens b2, and the pupil imaging chip b3 is a CCD or CMOS in the infrared light band. With such a design, the lighting and imaging effects will be relatively ideal. In fact, the types of the pupil imaging chip b3 and the infrared light source b6 can also be specifically considered according to actual conditions.

[0069] Preferably, the collimator c3 can convert the laser emitted by the frequency sweeping light source c1 into a spatial parallel beam in the C1 sub-optical path, and can also couple the fundus return light in the C1 sub-optical path to the optical fiber in the C2 sub-optical path. The C1 sub-optical path and the C2 sub-optical path perform mutual conversion between the spatial beam and the optical fiber beam through the collimator c3. Such a design can realize the stable conversion between the optical fiber laser and the spatial beam. In fact, the type of collimator c3 can also be specifically considered according to the actual situation.

[0070] Preferably, the laser emitted by the frequency sweeping light source c1 is divided into two beams through the first coupler c2, one beam is transmitted to the collimator c3 through the optical fiber, and the other beam is transmitted to the second coupler c8 through the optical fiber. The first coupler c2 can receive the fundus return light from the collimator c3 and transmit the fundus return light to the dispersion compensator c6. Such a design is conducive to the miniaturization of the optical fiber optical path and reduces the complexity of the system. In fact, the type of the second coupler c8 can also be specifically considered according to the actual situation.

[0071] Preferably, the dispersion compensator c6 can receive the fundus return light transmitted by the first coupler c2, and transmit the fundus return light to the polarization controller c7. The dispersion compensator c6 is a combination of a fiber filament of a specific length and a glass block of a specific material, which can compensate for the group dispersion of the optical system and match the optical path difference. Such a design can improve the resolution of coherent measurement and improve the tomographic imaging effect. In fact, the type of dispersion compensator c6 can also be specifically considered according to actual conditions.

[0072] Preferably, the second coupler c8 is a 5:5 fiber coupler, the reference laser emitted by the frequency sweeping light source c1 interferes with the fundus return light emitted from the polarization controller c7 in the second coupler c8, the interfered light beam is received by the photodetector c9 and converted into an electrical signal required for imaging, and the photodetector c9 is a balanced detector. Such a design can achieve high-sensitivity photoelectric conversion. In fact, the types of the second coupler c8 and the photodetector c9 can also be specifically considered according to actual conditions.

[0073] Preferably, the frequency-sweeping light source c1 is a frequency-sweeping laser with a wavelength range of 1000nm to 1200nm; the polarization controller c7 is a three-ring polarization controller that can change the polarization state of the light beam. Such a design can ensure the best retinal imaging quality. In fact, the types of frequency-sweeping light source c1 and polarization controller c7 can also be specifically considered according to actual conditions.

[0074] Example 2

[0075] The working method of the optical system of the color three-dimensional fundus imager comprises the following steps:

[0076] S1: Complete the human eye positioning and focusing work

[0077] The B optical path starts working first. The infrared light source b6 emits infrared light and illuminates the pupil of the human eye through the B2 sub-optical path. Then the infrared return light of the human eye pupil is imaged on the pupil imaging chip b3 through the B1 sub-optical path. The main function of the B optical path is to locate and focus the human eye. By real-time monitoring of the center position of the pupil and the clarity of the pupil image, it can ensure that the center of the human eye pupil is aligned with the optical axis of the optical system and lock the human eye pupil at the front focal plane of the large objective lens abc1.

[0078] S2: A optical path fixes the human eye and generates a retinal guidance image

[0079] After completing the work of eye positioning and focusing, the A optical path starts to work. First, the sight mark light a7 emits a fixation pattern to the human eye retina through the A3 sub-optical path to guide the human eye to fixate. Then the ring light source a9 emits visible light through the A2 sub-optical path to illuminate the human eye retina, and the return light from the human eye retina is imaged on the retinal imaging chip a5 through the A1 sub-optical path. The main functions of the A optical path are fundus color imaging and human eye fixation. The A3 sub-optical path is in working condition during the operation of the entire optical system to ensure that the human eye always fixes relative to the optical system. Before the C optical path scans and images, the ring light source a9 emits monochromatic weak light, and a black and white retinal guide image is formed on the retinal imaging chip a5.

[0080] S3: Realize color 2D imaging and 3D tomographic imaging of the fundus

[0081] After the A optical path generates the retinal guide image, the C optical path starts to work: first, the deflection angle of the three-dimensional galvanometer c4 in the C optical path is reset to zero, and the laser intended scanning area is set on the fundus according to the retinal guide image generated by the A optical path; then the scanning light source c1 of the C optical path emits laser, and sends the laser to the three-dimensional galvanometer c4 in the C1 sub-optical path through the C2 sub-optical path, and the three-dimensional galvanometer c4 deflects the galvanometer to complete the tomographic imaging of the laser in the set area of ​​the fundus; when the C optical path completes the scanning imaging, the annular light source a9 in the A optical path emits three-color strong light to realize color two-dimensional imaging of the fundus.

[0082] Preferably, the operating band of the A optical path is 400nm to 760nm, and the visible light imaging optical path can not only guide the human eye to fixate, but also perform red, green and blue imaging of the fundus separately and white light full-color imaging. The operating band of the B optical path is 800nm ​​to 890nm, and its main function is to locate and focus the human eye. The infrared imaging optical path does not participate in the color three-dimensional reconstruction of the retina. It is an optical component that assists in completing fully automatic fundus imaging. It can automatically locate the center of the human pupil and ensure that the optical system is aligned with the center of the human pupil. The infrared imaging optical path is a fixed-focus optical path, which can assist the optical system in determining whether the human pupil is located at the front focal plane of the large objective lens abc1 to ensure that the human eye is located at the optimal imaging position. The operating band of the C optical path is 900nm to 1200nm, and its main function is laser scanning imaging of the human retina, which can complete tomographic imaging of any range or position of the retina. The laser imaging optical path is the main optical path of the optical system. The visible light imaging optical path and the infrared imaging optical path are respectively connected to the main optical path through two different dichroic mirrors and share the large objective lens abc1. This design can ensure that the optical paths do not affect each other while reducing the system volume and improving the stability of the system.

[0083] Preferably, the large objective lens abc1 is coated with an anti-reflection film in the wavelength range of 400nm to 1200nm, the first dichroic mirror abc2 is set to transmit infrared light in the wavelength range of 800nm ​​to 1200nm, and reflect visible light in the wavelength range of 400nm to 760nm, and the second dichroic mirror bc1 is set to transmit infrared light in the wavelength range of 900nm to 1200nm, and reflect infrared light in the wavelength range of 800nm ​​to 890nm. Such a design can effectively ensure that the imaging of each optical path does not affect each other. In fact, the working bands of the first dichroic mirror abc2 and the second dichroic mirror bc1 and the coating range of the large objective lens abc1 can also be specifically considered according to actual needs.

[0084] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A color three-dimensional fundus imager optical system, characterized in that: The invention comprises an eyepiece large objective lens (abc1), a first dichroic mirror (abc2), a second dichroic mirror (bc1), a scanning lens (c5), a three-dimensional galvanometer (c4) and a collimator (c3) are sequentially arranged on the right side of the eyepiece large objective lens (abc1), a hollow reflector (a1), a focusing lens (a2), a first beam splitter (a3), a retinal lens (a4) and a retinal imaging chip (a5) are sequentially arranged below the first dichroic mirror (abc2), and a hollow reflector (a1), a focusing lens (a2), a first beam splitter (a3), a retinal lens (a4) and a retinal imaging chip (a5) are sequentially arranged below the first dichroic mirror (abc2). An illumination lens (a8) and an annular light source (a9) are sequentially arranged on the right side of the mirror (a1); a fixation lens (a6) and a sight mark light (a7) are sequentially arranged on the right side of the first beam splitter (a3); a second beam splitter (b1), a pupil lens (b2) and a pupil imaging chip (b3) are sequentially arranged above the second dichroic mirror (bc1); an infrared lens (b4), an infrared homogenizing lens (b5) and an infrared light source (b6) are sequentially arranged on the right side of the second beam splitter (b1).

2. The color three-dimensional fundus imager optical system according to claim 1, characterized in that: The invention also includes a frequency sweeping light source (c1), a first coupler (c2), a dispersion compensator (c6), a polarization controller (c7), a second coupler (c8) and a photodetector (c9); one end of the collimator (c3) is connected to the first end of the first coupler (c2) through an optical fiber; the second end of the first coupler (c2) is respectively connected to the frequency sweeping light source (c1) and the first end of the dispersion compensator (c6) through an optical fiber; the second end of the dispersion compensator (c6) is connected to the first end of the polarization controller (c7) through an optical fiber; the second end of the polarization controller (c7) is connected to the first end of the second coupler (c8) through an optical fiber; the first end of the first coupler (c2) is also connected to the first end of the second coupler (c8) through an optical fiber; the second end of the second coupler (c8) is respectively connected to the first end and the second end of the photodetector (c9).

3. The color three-dimensional fundus imager optical system according to claim 1, characterized in that: The pupil of the human eye is located at the front focal plane of the large eyepiece lens (abc1), the first dichroic mirror (abc2) is located at the rear focal plane of the large eyepiece lens (abc1), and the rear focal plane of the large eyepiece lens (abc1) coincides with the front focal plane of the scanning lens (c5), the front focal plane of the focusing lens (a2), the front focal plane of the pupil lens (b2), the front focal plane of the illumination lens (a8), and the front focal plane of the infrared lens (b4).

4. The color three-dimensional fundus imager optical system according to claim 1, characterized in that: The large eyepiece objective lens (abc1), the first dichroic mirror (abc2), the hollow reflector (a1), the focusing lens (a2), the first beam splitter (a3), the retinal lens (a4), the retinal imaging chip (a5), the fixation lens (a6), the sight mark light (a7), the illumination lens (a8) and the annular light source (a9) form a visible light imaging optical path, which is recorded as the A optical path.

5. The color three-dimensional fundus imager optical system according to claim 1, characterized in that: The large eyepiece objective lens (abc1), the first dichroic mirror (abc2), the second dichroic mirror (bc1), the second beam splitter (b1), the pupil lens (b2), the pupil imaging chip (b3), the infrared lens (b4), the infrared homogenizing lens (b5) and the infrared light source (b6) form an infrared imaging optical path, which is recorded as the B optical path.

6. The color three-dimensional fundus imager optical system according to claim 1, characterized in that: The large objective lens (abc1), the first dichroic mirror (abc2), the second dichroic mirror (bc1), the scanning lens (c5), the three-dimensional galvanometer (c4), the collimator (c3), the first coupler (c2), the swept-frequency light source (c1), the dispersion compensator (c6), the polarization controller (c7), the second coupler (c8) and the photodetector (c9) constitute a laser imaging optical path, which is denoted as the C optical path.

7. The color three-dimensional fundus imager optical system according to claim 1, characterized in that: In the A optical path, the large eyepiece objective lens (abc1), the first dichroic mirror (abc2), the hollow reflector (a1), the focusing lens (a2), the first beam splitter (a3), the retinal lens (a4) and the retinal imaging chip (a5) constitute a fundus imaging optical path, which is recorded as the A1 sub-optical path; the large eyepiece objective lens (abc1), the first dichroic mirror (abc2), the hollow reflector (a1), the illumination lens (a8) and the annular light source (a9) constitute a fundus illumination optical path, which is recorded as the A2 sub-optical path; the large eyepiece objective lens (abc1), the first dichroic mirror (abc2), the hollow reflector (a1), the focusing lens (a2), the first beam splitter (a3), the fixation lens (a6) and the sight mark light (a7) constitute a fixation light path, which is recorded as the A3 sub-optical path.

8. The color three-dimensional fundus imager optical system according to claim 1, characterized in that: In the B optical path, the large eyepiece objective lens (abc1), the first dichroic mirror (abc2), the second dichroic mirror (bc1), the second beam splitter (b1), the pupil lens (b2) and the pupil imaging chip (b3) constitute the pupil imaging optical path, which is recorded as the B1 sub-optical path; the large eyepiece objective lens (abc1), the first dichroic mirror (abc2), the second dichroic mirror (bc1), the second beam splitter (b1), the infrared lens (b4), the infrared homogenizing lens (b5) and the infrared light source (b6) constitute the pupil illumination optical path, which is recorded as the B2 sub-optical path.

9. The color three-dimensional fundus imager optical system according to claim 1, characterized in that: In the C optical path, the eyepiece objective lens (abc1), the first dichroic mirror (abc2), the dichroic mirror (bc1), the scanning lens (c5), the three-dimensional galvanometer (c4) and the collimator (c3) constitute the spatial optical path part of the C optical path, which is recorded as the C1 sub-optical path; the collimator (c3), the coupler (c2), the swept-frequency light source (c1), the dispersion compensator (c6), the polarization controller (c7), the coupler (c8) and the photodetector (c9) constitute the optical fiber optical path part of the C optical path, which is recorded as the C2 sub-optical path.

10. A method for operating the color three-dimensional fundus imager optical system according to any one of claims 1 to 9, characterized in that: The steps include: S1: Complete the work of eye positioning and focusing; S2: A optical path fixes the human eye and generates a retinal guidance image; S3: Realize color two-dimensional imaging and three-dimensional tomographic imaging of the fundus.

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