Line scanning ultra-wide angle fundus imaging system and imaging method

Abstract

According to the line scanning ultra-wide-angle fundus imaging system and method, the super-lens is adopted to replace an eye objective lens in traditional fundus photographing, fundus ultra-wide-angle imaging is achieved, the super-lens can form an ultra-wide-angle middle image plane of fundus retina by adopting a single lens, the structure is compact and small, the size is very light, and the imaging effect is good. The size and the weight of the ultra-wide-angle fundus imaging system are greatly reduced; as the super lens only has two reflecting surfaces which may cause stray light, and the traditional eye objective lens adopts a plurality of lenses, and each lens has two reflecting surfaces which may cause stray light, the stray light during system imaging is reduced by adopting the super lens, and the system complexity and difficulty caused by stray light suppression are also greatly reduced.

Description

Technical Field

[0001] The present application relates to the technical field of fundus scanning imaging, and in particular to a line scanning ultra-wide-angle fundus imaging system and imaging method. Background Art

[0002] Among all blinding eye diseases, fundus disease is the main cause of irreversible vision loss. The treatment process of fundus disease is long, and early screening, early diagnosis, and early treatment are the key to preventing and treating fundus disease. The optic nerve and posterior pole areas such as the macula have always been considered the two most important parts of the fundus. However, various ischemic diseases, inflammatory diseases, degenerative diseases, degenerative changes, some tumors, and some genetic diseases can cause peripheral retinal lesions. Many fundus diseases start to develop from the periphery and then gradually involve the macular area. When the lesions do not involve the macular area, patients tend to ignore early lesions because their vision is not significantly affected and no symptoms occur. When examining patients, ordinary fundus imaging equipment cannot observe the peripheral area of ​​the fundus. When the lesions involve the central macular area of ​​the fundus, the difficulty of treatment is greatly increased and the prognosis is poor. Therefore, it is of great significance to develop imaging instruments that can examine the retina including the peripheral part of the fundus.

[0003] Traditional fundus photography and fundus angiography have a small imaging field and low image clarity. They can only shoot within a range of about 50° at a time, and cannot capture the peripheral area of ​​the fundus. Scanning laser ophthalmoscopy (SLO) uses laser points to scan the fundus point by point and line by line. It has high imaging contrast and a large fundus imaging field, and can achieve ultra-wide-angle imaging. The disadvantage is that it uses laser as the illumination light source, which poses certain laser safety risks. In addition, the laser spectrum width is very narrow, and several wavelengths of laser are used to image the fundus separately. The fundus color image is obtained by image fusion, and the image color has relatively large distortion.

[0004] Line scanning fundus imaging can use LED light source as the illumination light source, and through the multi-wavelength LED synthetic white light source, fundus imaging can be achieved in true color. The disadvantage is that the core component in line scanning fundus imaging - the eyepiece objective adopts traditional optical design, and ultra-wide-angle imaging is achieved by optimizing the lens's surface radius, aspheric parameters, thickness, material, and combination of multiple lenses. It requires a combination of multiple lenses, and there is stray light formed by scattering or reflection on the lens surface. Due to the presence of multiple lenses, each lens has two surfaces, which greatly increases the probability of stray light, causing more serious stray light to the imaging. Suppressing stray light will bring greater difficulties to the development of the system; in addition, the eyepiece objective is relatively large in size and weight, which makes the line scanning ultra-wide-angle fundus imaging device using this type of eyepiece objective also large in size and weight. Summary of the invention

[0005] In view of this, it is necessary to provide a line scanning ultra-wide-angle fundus imaging system and imaging method that can reduce the stray light, volume and weight of the system during imaging, in order to address the defects of the prior art fundus scanning imaging, such as severe stray light and large size and weight.

[0006] To solve the above problems, this application adopts the following technical solutions:

[0007] One of the purposes of the present application is to provide a line scanning ultra-wide-angle fundus imaging system, comprising: an illumination optical path, an imaging detection optical path, and a sight mark projection optical path, wherein:

[0008] The illumination optical path includes: an LED light source, a condenser, an illumination slit, an illumination lens, a one-dimensional scanning galvanometer, a scanning lens, a beam splitter and a super lens; the imaging detection optical path includes the super lens, the beam splitter, the scanning lens, the one-dimensional scanning galvanometer, a detection beam splitter, a first imaging objective lens, a detection slit, a second imaging objective lens and a camera; the sight mark projection optical path includes a sight mark projection screen, a projection lens, the beam splitter and the super lens;

[0009] The LED light source is irradiated onto the illumination slit through the condenser, and the linear light beam emitted from the illumination slit propagates forward through the illumination lens, and is then partially blocked by the detection beam splitter, and the unblocked portion passes through the one-dimensional scanning galvanometer and the scanning lens in turn and enters the beam splitter, and the beam splitter reflects most of the light beam into the super lens, and the super lens transmits the incident light beam to the pupil of the human eye, and forms a linear illumination area at the fundus after passing through the human eye and the super lens, and forms an intermediate image plane of the retina after the linear illumination area of ​​the fundus passes through the human eye and the super lens, and the intermediate image plane is reflected by the beam splitter and enters the scanning lens, and then The light beam then enters the one-dimensional scanning galvanometer, which reflects the incident light beam into the detection beam splitter. The detection beam splitter reflects a part of the imaging light beam into the first imaging objective lens, which is gathered at the detection slit through the first imaging objective lens. The light beam emitted from the detection slit is imaged and focused on the photosensitive surface of the camera through the second imaging objective lens. The light beam emitted by the sight mark on the sight mark projection screen passes through the projection lens and enters the beam splitter. A small part of the light beam is transmitted by the beam splitter and enters the super lens. The light beam emitted from the super lens enters the human eye, guiding the inspected person to look at the sight mark projection screen along the set viewing angle.

[0010] In some of the embodiments, a metasurface structure is disposed on a side of the metalens close to the scanning lens, and the metasurface structure is composed of sub-wavelength structural unit meta-atoms.

[0011] In some embodiments, the retina position R of the human eye, the image plane position P of the metalens, the slit position S1 of the illumination slit, the slit position S2 of the detection slit, and the sight mark position M of the sight mark projection screen are located at optically conjugate positions.

[0012] In some embodiments, the illumination slit and the detection slit are both configured as thin line slits.

[0013] In some of the embodiments, the illumination slit is configured as a thin line slit, the detection slit is configured as a wide line slit, and the camera is a linear array camera.

[0014] In some of the embodiments, the illumination slit is configured as a wide line slit, the detection slit is configured as a wide line slit, and the camera is a TDI camera or an area array camera.

[0015] In some of the embodiments, the sight mark projection screen generates a sight mark at a preset position on the screen to guide the person being examined to look at the sight mark.

[0016] In some of the embodiments, the sight mark projection screen may be an electronic display screen or a projection screen.

[0017] In some of the embodiments, the one-dimensional scanning galvanometer is connected to a control unit, and the control unit can control the one-dimensional scanning galvanometer to swing. Every time the one-dimensional scanning galvanometer swings a small angle, the linear area illuminated by the line light beam in the fundus moves one position. The camera can record image information of the illuminated linear area of ​​the fundus, and obtain an ultra-wide-angle image of the fundus through image reconstruction.

[0018] The second object of the present application is to provide an imaging method of the line scanning ultra-wide-angle fundus imaging system, comprising the following steps:

[0019] The LED light source is irradiated onto the illumination slit through the condenser, and the linear light beam emitted from the illumination slit propagates forward through the illumination lens, and is then partially blocked by the detection beam splitter, and the unblocked portion passes through the one-dimensional scanning galvanometer and the scanning lens in turn and enters the beam splitter, and the beam splitter reflects most of the light beam into the super lens, and the super lens transmits the incident light beam to the pupil of the human eye, and forms a linear illumination area at the fundus after passing through the human eye and the super lens, and forms an intermediate image plane of the retina after the linear illumination area of ​​the fundus passes through the human eye and the super lens, and the intermediate image plane is reflected by the beam splitter and enters the scanning lens, and then The light beam then enters the one-dimensional scanning galvanometer, which reflects the incident light beam into the detection beam splitter. The detection beam splitter reflects a part of the imaging light beam into the first imaging objective lens, which is focused at the detection slit through the first imaging objective lens. The light beam emitted from the detection slit is imaged and focused on the photosensitive surface of the camera through the second imaging objective lens. The light beam emitted from the sight mark on the sight mark projection screen passes through the projection lens and enters the beam splitter. A small part of the light beam is transmitted by the beam splitter and enters the super lens. The light beam emitted from the super lens enters the human eye, guiding the inspected person to look at the sight mark projection screen along the set viewing angle.

[0020] This application adopts the above technical solution, and its beneficial effects are as follows:

[0021] The line scanning ultra-wide-angle fundus imaging system and imaging method provided by the present application adopt a super lens to replace the eye contact objective lens in traditional fundus photography to achieve ultra-wide-angle fundus imaging. The super lens adopts a single lens to form an ultra-wide-angle intermediate image plane of the fundus retina. It has a compact structure and a light volume, which greatly reduces the volume and weight of the ultra-wide-angle fundus imaging system. Since the super lens has only two reflection surfaces that may cause stray light, while the traditional eye contact objective lens adopts multiple lenses, each lens has two reflection surfaces that may cause stray light. The use of the super lens reduces the stray light during system imaging, and also greatly reduces the system complexity and difficulty caused by suppressing stray light.

[0022] In addition, the present application provides a detection spectroscope in the optical path system, which effectively utilizes a part of both the illumination beam and the detection beam, and can effectively suppress the stray light caused by the scanning lens, the super lens and the human cornea. The detection slit in the imaging detection optical path can play the role of the confocal slit during line scanning confocal imaging, and can also serve as a device for blocking the stray light of the optical path system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A schematic diagram of the structure of a line scanning ultra-wide-angle fundus imaging system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0025] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0026] In the description of the present application, it should be understood that the terms "upper", "lower", "horizontal", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0027] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0028] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0029] See also Figure 1 The line scanning ultra-wide-angle fundus imaging system provided in the embodiment of the present application includes: an illumination optical path 10, an imaging detection optical path 20 and a control system 30. The specific implementation of each component is described in detail below.

[0030] The illumination optical path 10 includes: an LED light source 11 , a condenser 12 , an illumination slit 13 , an illumination lens 14 , a one-dimensional scanning galvanometer 15 , a scanning lens 16 , a beam splitter 17 and a super lens 18 .

[0031] The imaging detection optical path 20 includes the superlens 18 , the beam splitter 17 , the scanning lens 16 , the one-dimensional scanning galvanometer 15 , a detection beam splitter 21 , a first imaging objective lens 22 , a detection slit 23 , a second imaging objective lens 24 and a camera 25 .

[0032] The sight mark projection optical path 30 includes a sight mark projection screen 31 , a projection lens 32 , the beam splitter 17 and the super lens 18 .

[0033] The line scanning ultra-wide-angle fundus imaging system provided in the above embodiment of the present application works as follows:

[0034] The LED light source 11 is irradiated onto the illumination slit 13 through the condenser 12. The linear light beam emitted from the illumination slit 13 propagates forward through the illumination lens 14, and is then partially blocked by the detection beam splitter 21. The unblocked portion passes through the one-dimensional scanning galvanometer 15 and the scanning lens 16 in sequence and enters the beam splitter 17. The beam splitter 17 reflects most of the light beam into the super lens 18. The super lens 18 transmits the incident light beam to the pupil of the human eye, and forms a linear illumination area at the fundus after passing through the human eye's refractive system. The linear illumination area of ​​the fundus forms an intermediate image plane of the retina after passing through the human eye and the super lens 18. The intermediate image plane is reflected by the beam splitter 17 and enters the scanning lens 16, and then enters The light beam enters the one-dimensional scanning galvanometer 15, and the one-dimensional scanning galvanometer 15 reflects the incident light beam into the detection beam splitter 21. The detection beam splitter 21 reflects a part of the imaging light beam into the first imaging objective lens 22, and the first imaging objective lens 22 focuses the light beam at the detection slit 23. The light beam emitted from the detection slit 23 is imaged and focused on the photosensitive surface of the camera 25 through the second imaging objective lens 24. The sight mark on the sight mark projection screen 31 emits a light beam and enters the beam splitter 17 after passing through the projection lens 32. A small part of the light beam is transmitted by the beam splitter 17 and enters the super lens 18. The light beam emitted from the super lens 18 enters the human eye, guiding the inspected person to look at the sight mark projection screen 31 along the set viewing angle.

[0035] It can be understood that since a part of the detection beam splitter 21 is located in the optical path, a part of the illumination light beam is blocked by the detection beam splitter 21, and the other part can be directly transmitted. A part of the detection light beam is reflected by the detection beam splitter 21 into the subsequent imaging optical path to participate in imaging, and the other part is not blocked by the detection beam splitter 21 and directly propagates forward and does not participate in imaging. The detection beam splitter 21 serves the purpose of eliminating stray light caused by reflection or scattering of the scanning lens 16, the super lens 18, and the human cornea.

[0036] In this embodiment, a metasurface structure composed of sub-wavelength structural unit meta-atoms is provided on the side of the superlens 18 close to the scanning lens 16, and the superlens forms an intermediate image plane of the retina of the human eye between the superlens and the scanning lens. The superlens 18 can achieve a large imaging field angle and realize ultra-wide-angle imaging of the fundus; the superlens structure is small and compact, and a single lens can achieve a large imaging field angle.

[0037] In this embodiment, the retinal position R of the human eye, the image plane position P of the super lens 18, the slit position S1 of the illumination slit 13, the slit position S2 of the detection slit 23, and the sight mark position M of the sight mark projection screen 31 are located at optically conjugate positions.

[0038] In some embodiments, the illumination slit 13 and the detection slit 23 are simultaneously configured as thin line slits, and line scanning confocal imaging can be performed at this time.

[0039] In some embodiments, the illumination slit 13 is set as a thin line slit, the detection slit 23 is set as a wide line slit, and the camera adopts a linear array camera. In this case, line scanning confocal fundus imaging can also be performed. At this time, the pixel boundary of the camera plays the role of a confocal detection slit, and the detection slit 23 plays the role of blocking the stray light generated by the system.

[0040] In some embodiments, the illumination slit 13 is configured as a wide line slit, the detection slit 23 is also configured as a wide line slit, and the camera 25 is a TDI camera or an area array camera. In this case, wide line beam line scanning imaging can be performed to improve the imaging speed and signal-to-noise ratio.

[0041] Furthermore, the sight mark projection screen 31 generates a sight mark at a pre-set position on the screen to guide the person being examined to look at the sight mark, thereby achieving the purpose of photographing different areas of the fundus of the human eye and stabilizing the human eye during the photographing process; the sight mark projection screen 31 can be an electronic display screen, or it can be a projection screen composed of a light source and sight marks, in which different areas of the sight marks are illuminated separately.

[0042] Furthermore, the one-dimensional scanning galvanometer 15 is connected to a control unit (not shown), and the control unit can control the one-dimensional scanning galvanometer 15 to swing. Every time the one-dimensional scanning galvanometer 15 swings a small angle, the linear area illuminated by the line light beam in the fundus moves one position, and the camera 25 can record the image information of the illuminated linear area of ​​the fundus, and obtain an ultra-wide-angle image of the fundus through image reconstruction.

[0043] The line scanning ultra-wide-angle fundus imaging system provided in the above-mentioned embodiment of the present application adopts a super lens 18 to replace the eyepiece objective lens in traditional fundus photography to realize ultra-wide-angle fundus imaging. The super lens 18 adopts a single lens to form an ultra-wide-angle intermediate image plane of the fundus retina. It has a compact and small structure and a very light volume, which greatly reduces the volume and weight of the ultra-wide-angle fundus imaging system. Since the super lens 18 has only two reflection surfaces that may cause stray light, and the traditional eyepiece objective lens adopts multiple lenses, each lens has two reflection surfaces that may cause stray light. The use of the super lens reduces the stray light during system imaging, and also greatly reduces the system complexity and difficulty caused by suppressing stray light.

[0044] In addition, the present application is provided with a detection spectroscope 21 in the optical path system, and the detection spectroscope 21 effectively utilizes a part of both the illumination beam and the detection beam, and can effectively suppress the stray light caused by the scanning lens 16, the super lens 18 and the human cornea. The detection slit in the imaging detection optical path can not only play the role of the confocal slit in line scanning confocal imaging, but also be used as a device to block the stray light of the optical path system. It can be understood that the technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0045] The above are only preferred embodiments of the present application, and only specifically describe the technical principles of the present application. These descriptions are only for explaining the principles of the present application and cannot be interpreted as limiting the scope of protection of the present application in any way. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, and other specific implementation methods of the present application that can be associated with the technicians in this field without creative work, should be included in the scope of protection of the present application.

Claims

1. A line scanning ultra-wide-angle fundus imaging system, characterized in that: include: Illumination optical path, imaging detection optical path and sight mark projection optical path, where: The illumination optical path includes: an LED light source, a condenser, an illumination slit, an illumination lens, a one-dimensional scanning galvanometer, a scanning lens, a beam splitter and a super lens; the imaging detection optical path includes the super lens, the beam splitter, the scanning lens, the one-dimensional scanning galvanometer, a detection beam splitter, a first imaging objective lens, a detection slit, a second imaging objective lens and a camera; the sight mark projection optical path includes a sight mark projection screen, a projection lens, the beam splitter and the super lens; The LED light source is irradiated onto the illumination slit through the condenser, and the linear light beam emitted from the illumination slit propagates forward through the illumination lens, and is then partially blocked by the detection beam splitter, and the unblocked portion passes through the one-dimensional scanning galvanometer and the scanning lens in turn and enters the beam splitter, and the beam splitter reflects most of the light beam into the super lens, and the super lens transmits the incident light beam to the pupil of the human eye, and forms a linear illumination area at the fundus after passing through the human eye and the super lens, and forms an intermediate image plane of the retina after the linear illumination area of ​​the fundus passes through the human eye and the super lens, and the intermediate image plane is reflected by the beam splitter and enters the scanning lens, and then The light beam then enters the one-dimensional scanning galvanometer, which reflects the incident light beam into the detection beam splitter. The detection beam splitter reflects a part of the imaging light beam into the first imaging objective lens, which is focused at the detection slit through the first imaging objective lens. The light beam emitted from the detection slit is imaged and focused on the photosensitive surface of the camera through the second imaging objective lens. The light beam emitted from the sight mark on the sight mark projection screen passes through the projection lens and enters the beam splitter. A small part of the light beam is transmitted by the beam splitter and enters the super lens. The light beam emitted from the super lens enters the human eye, guiding the inspected person to look at the sight mark projection screen along the set viewing angle.

2. The line scanning ultra-wide-angle fundus imaging system according to claim 1, characterized in that: A super surface structure is arranged on one side of the super lens close to the scanning lens, and the super surface structure is composed of sub-wavelength structural unit super atoms.

3. The line scanning ultra-wide-angle fundus imaging system according to claim 1, characterized in that: The retina position R of the human eye, the image plane position P of the metalens, the slit position S1 of the illumination slit, the slit position S2 of the detection slit, and the sight mark position M of the sight mark projection screen are located at optically conjugate positions.

4. The line scanning ultra-wide-angle fundus imaging system according to claim 1, characterized in that: The illumination slit and the detection slit are simultaneously configured as thin line slits.

5. The line scanning ultra-wide-angle fundus imaging system according to claim 1, characterized in that: The illumination slit is configured as a thin line slit, the detection slit is configured as a wide line slit, and the camera is a linear array camera.

6. The line scanning ultra-wide-angle fundus imaging system according to claim 1, characterized in that: The illumination slit is configured as a wide line slit, the detection slit is configured as a wide line slit, and the camera is a TDI camera or an area array camera.

7. The line scanning ultra-wide-angle fundus imaging system according to claim 1, characterized in that: The sight mark projection screen generates a sight mark at a preset position on the screen to guide the person being examined to look at the sight mark.

8. The line scanning ultra-wide-angle fundus imaging system according to claim 1 or 7, characterized in that: The sight mark projection screen can be an electronic display screen or a projection screen.

9. The line scanning ultra-wide-angle fundus imaging system according to claim 1, characterized in that: The one-dimensional scanning galvanometer is connected to a control unit, which can control the one-dimensional scanning galvanometer to swing. Every time the one-dimensional scanning galvanometer swings a small angle, the linear area illuminated by the line light beam in the fundus moves one position. The camera can record the image information of the illuminated linear area of ​​the fundus, and obtain an ultra-wide-angle image of the fundus through image reconstruction.

10. An imaging method of the line scanning ultra-wide-angle fundus imaging system according to claim 1, characterized in that: The steps include: The LED light source is irradiated onto the illumination slit through the condenser, and the linear light beam emitted from the illumination slit propagates forward through the illumination lens, and is then partially blocked by the detection beam splitter, and the unblocked portion passes through the one-dimensional scanning galvanometer and the scanning lens in turn and enters the beam splitter, and the beam splitter reflects most of the light beam into the super lens, and the super lens transmits the incident light beam to the pupil of the human eye, and forms a linear illumination area at the fundus after passing through the human eye and the super lens, and forms an intermediate image plane of the retina after the linear illumination area of ​​the fundus passes through the human eye and the super lens, and the intermediate image plane is reflected by the beam splitter and enters the scanning lens, and then The light beam then enters the one-dimensional scanning galvanometer, which reflects the incident light beam into the detection beam splitter. The detection beam splitter reflects a part of the imaging light beam into the first imaging objective lens, which is focused at the detection slit through the first imaging objective lens. The light beam emitted from the detection slit is imaged and focused on the photosensitive surface of the camera through the second imaging objective lens. The light beam emitted from the sight mark on the sight mark projection screen passes through the projection lens and enters the beam splitter. A small part of the light beam is transmitted by the beam splitter and enters the super lens. The light beam emitted from the super lens enters the human eye, guiding the inspected person to look at the sight mark projection screen along the set viewing angle.

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