CN113509142A

CN113509142A - Large-visual-field retina examination device

Info

Publication number: CN113509142A
Application number: CN202110630800.1A
Authority: CN
Inventors: 齐岳; 王熙; 赵鹏; 张锟; 王雪乔
Original assignee: Tianjin Suowei Electronic Technology Co ltd
Current assignee: Tianjin Suowei Electronic Technology Co ltd
Priority date: 2021-06-07
Filing date: 2021-06-07
Publication date: 2021-10-19
Anticipated expiration: 2041-06-07
Also published as: CN113509142B

Abstract

The invention relates to a large-visual-field retina examination device, which is characterized in that: the interferometer is connected with a sample arm light path in the probe through an optical fiber pigtail in the interferometer; the probe is used for carrying out color imaging and fluorescence contrast imaging on the fundus and is also used as a sample arm light path for optical coherence tomography imaging; the interferometer is used for optical coherence tomography of the retina of the eye. The device can display the retina tomogram while carrying out real-time color shooting on the retina of the eye, and can also carry out fluorescence radiography imaging. The shot image can be used for screening the fundus diseases in all aspects, and is particularly suitable for early diagnosis and postoperative reexamination of the infant fundus retinopathy.

Description

Large-visual-field retina examination device

Technical Field

The invention belongs to the technical field of ophthalmological images, and relates to a large-visual-field fundus examination device which takes a white light LED and a near-infrared broadband laser as illumination light sources and images through an optical lens, a camera and a spectrometer, in particular to a large-visual-field retina examination device.

Background

Retinal imaging techniques have been widely used in the field of fundus disease detection. The medicine shows that the ophthalmology disease and the systemic disease of the body can generate pathological changes on the retina of the eye fundus at the early stage of the onset. The method can accurately and timely detect retinopathy, play an important role in early diagnosis of diseases, and provide a good technical platform for pathological research of serious diseases. In the clinic, the performance of the apparatus varies according to the population of subjects and the examination requirements, and for example, a large-visual-field fundus imaging apparatus is advantageous in the evaluation of pathological features in the peripheral region of the retina. Also for example, tomographic imaging devices have advantages in retinal morphological analysis.

The most common diagnostic device for the fundus diseases is a fundus camera, the imaging visual field of the fundus camera does not exceed 50 degrees generally, pathological feature analysis of the peripheral area of the retina cannot be completed, and the bottleneck is brought to the diagnosis of a plurality of diseases. For example, clinical early screening for retinopathy of prematurity (ROP), which can heal by laser surgery early in onset but can result in lifelong blindness, requires an imaging field of view of 120 degrees or more.

Patent US5822036 discloses a hand-held large field of view fundus imaging apparatus. The invention adopts a halogen lamp light source and a large number of optical fibers arranged into an illumination light ring which is placed behind the edge of the contact lens to illuminate the eyeground, and the illumination field of view can be improved to more than 120 degrees. The invention also provides an annular prism between the optical fiber and the contact lens for controlling the illumination uniformity of the fundus. Therefore, the method has high design difficulty and complex manufacturing process. Most importantly, the invention does not provide a tomographic image of the retina.

Patent US20090268020 discloses a hand-held large-field fundus tomographic imaging apparatus. The invention realizes the tomography of the retina by using the weak optical coherence technology. An imaging field of view of up to 140 degrees may be provided. However, this invention cannot provide a color image of the fundus in real time.

Disclosure of Invention

The present invention is intended to overcome the disadvantages of the prior art, and to provide a large-field retinal examination device which can display a tomographic image of the retina while performing real-time color imaging of the retina of the eye, and can perform fluoroscopic imaging. The shot image can be used for screening the fundus diseases in all aspects, and is particularly suitable for early diagnosis and postoperative reexamination of the infant fundus retinopathy.

The technical problem to be solved by the invention is realized by adopting the following technical scheme:

a large visual field retina examination device comprises a probe and an interferometer, wherein the interferometer is connected with a sample arm light path in the probe through a fiber pigtail in the interferometer;

the probe is used for carrying out color imaging and fluorescence contrast imaging on the fundus and is also used as a sample arm light path for optical coherence tomography imaging;

the interferometer is used for optical coherence tomography of the retina of the eye.

Moreover, the length of the probe does not exceed 250mm, and the weight of the probe does not exceed 3 kg.

Moreover, the probe consists of an illumination module, an eyeground imaging optical path and a sample arm optical path,

the lighting module comprises LED light sources, light homogenizing sheets and annular condensing lenses, wherein the LED light sources are arranged in a circular ring shape, the annular light homogenizing sheets are arranged in front of the formed circular ring, and the annular condensing lenses are arranged in front of the light homogenizing sheets.

When the LED light source emits light, the dodging sheet can be regarded as an annular luminous body with uniform brightness in all directions. An annular condenser lens is arranged in front of the light homogenizing sheet, and light can pass through a contact lens of the ocular lens group and be projected on the surface of the human eye crystal to form a light ring. These rays continue to travel forward and will spread out at the fundus to form a uniform illumination.

The fundus imaging light path is composed of an ocular lens group, an imaging objective lens, a dichroic mirror, a low pass filter, a fluorescent filter and an imaging camera, light rays emitted by the illumination module are collected by the ocular lens group after being reflected by the fundus and form an intermediate image surface R behind the ocular lens group, the imaging objective lens can carry out secondary imaging on the intermediate image surface, and a final fundus image R' is formed on the imaging camera through the dichroic mirror, the low pass filter or the fluorescent filter.

The sample arm optical path consists of a connecting eyepiece group, an imaging objective lens, a dichroic mirror, a high-pass filter, a scanning objective lens, a scanning galvanometer and a first collimating lens, wherein the connecting eyepiece group, the imaging objective lens, the dichroic mirror and an eyeground imaging optical path are shared,

the first collimating lens bends light emitted by an optical fiber tail fiber of the interferometer into parallel light, the parallel light is projected onto a scanning objective lens through a scanning vibrating mirror, the scanning objective lens converges the light on a back focal plane of the scanning objective lens to form a light spot, the position of the light spot on the focal plane is changed along with the change of the reflection angle of the scanning vibrating mirror to form a scanning image surface R, the light spot at any position in the R 'forms another equivalent light spot at the eye bottom of a human eye through a high-pass filter, a dichroic mirror and an imaging objective lens, the position of the equivalent light spot at the eye bottom can also be changed along with the change of the position of the light spot in the R', the scanning of the eye bottom is realized, the eye bottom can reflect the equivalent light spot, and the light can return to the optical fiber tail fiber through a sample arm light path to enter the interferometer.

Moreover, the LED light source is a patch type LED and is composed of white LEDs and blue LEDs which are arranged at intervals. The white light LED is a color imaging light source, the color temperature range is 4000K-5500K, and the color rendering index is not lower than 90%; the blue light LED is a fluorescence contrast light source, and the central wavelength range is 460 nm-490 nm. The number of each LED is not less than 6, and the light emitting angle is not less than 65 degrees.

The light homogenizing sheet is an acrylic plate or ground glass with a frosted surface, the surface roughness is not less than 1000 meshes, and the light transmittance is not less than 70%.

The annular condenser is an optical lens, one surface of the annular condenser is a plane, the curvature radius of the other surface of the annular condenser ranges from 2mm to 10mm, the curvature radius is determined by the refractive index of the material of the annular condenser, and the material of the annular condenser can be optical glass or optical resin.

And the ocular lens group consists of a contact lens, a conical lens and an ocular lens, and has the function of collecting light rays reflected by the eyeground to form a middle image surface R with good quality and low distortion.

The contact lens is an optical lens, needs to be in contact with the cornea of the human eye during working, and has a curvature radius close to that of the cornea of the human eye.

The cone-shaped lens is a cone-shaped optical lens, the material of the cone-shaped optical lens is different from that of the contact lens, the cone-shaped optical lens and the contact lens form a cemented lens for eliminating part of chromatic aberration of human eyes, and the illumination module is arranged on the outer ring of the cone-shaped lens.

The objective lens is 1 group of optical lens, and the function of the objective lens is to eliminate aberration of human eyes, wherein the aberration mainly comprises spherical aberration, coma aberration, chromatic aberration and distortion.

Moreover, the imaging objective lens is 1 group of optical lenses, the focal length range is 10 mm-100 mm, and the imaging objective lens at least comprises 1 cemented lens. The imaging objective lens moves back and forth along an imaging optical axis and is used for compensating individual difference of human eye diopter, so that an imaging image surface R' just falls on the imaging camera to form a clear fundus retina image. Moreover, the imaging objective lens also has image-side telecentric characteristics.

The dichroic mirror is an optical transflective mirror, the working angle is 45 degrees, and the dichroic mirror has the function of reflecting visible light and transmitting near infrared light at the same time, so that the visible light and the near infrared light are transmitted in mutually perpendicular directions after passing through the mirror, and the purpose of separation is achieved.

The low-pass filter is an optical filter, the working angle is 0 degree, the low-pass filter has the function of cutting off near infrared light while transmitting visible light, and the interference of the near infrared light entering an imaging camera on an image is avoided.

The fluorescent filter is an optical filter, the working angle is 0 degree, and the function of the fluorescent filter is to transmit green fluorescent light excited by the irradiation of the fluorescein by blue light and cut off light of other wave bands. A high contrast fluorescence contrast image is formed.

The imaging camera is a CCD or CMOS camera, has a photosensitive area not larger than 1 inch and a resolution not lower than 30 ten thousand pixels, and is positioned on an image plane R' of a fundus imaging optical path to form an image.

Moreover, the low-pass filter and the fluorescence filter are switched for use, and only one of the low-pass filter and the fluorescence filter can be in the fundus imaging optical path at a time. When the fundus is subjected to color imaging, a low-pass filter is used; and when fluorescence contrast imaging is performed on the fundus, a fluorescence filter is used.

And the first collimating lens is an optical lens, the focal length range is 5 mm-25 mm, and the numerical aperture is not more than 0.5.

The scanning galvanometer is a scanning reflector, the reflection angle can be periodically changed, the scanning frequency is not lower than 100Hz, and the scanning angle is not more than +/-20 degrees.

The scanning objective lens is 1 group of optical lens, and the focal length range is 20 mm-100 mm. Moreover, the scanning objective lens also has the characteristics of image space telecentricity and low distortion.

The high-pass filter is an optical filter, the working angle is 0 degree, the high-pass filter has the function of cutting off visible light while transmitting near infrared light, and interference caused by the fact that visible light enters an interferometer due to fundus reflection is avoided.

The interferometer consists of a weak coherent light source, a 2x2 optical fiber coupler, a polarization controller, a fiber pigtail, a reference arm optical path and a spectrometer and is used for carrying out optical coherence tomography on the retina of the eye;

the optical weak coherent light source is a super-radiation light emitting diode, the central wavelength range of the optical weak coherent light source is 780 nm-1100 nm, and the bandwidth is not narrower than 40 nm;

the 2x2 optical fiber coupler is an optical fiber device which is provided with 4 tail fibers which are respectively connected into a weak coherent light source, a sample arm light path, a reference arm light path and a spectrometer; the interferometer has the functions of respectively guiding light rays emitted by the weak coherent light source to enter the sample arm light path and the reference arm light path according to a set proportion, collecting return light of the two light paths to form an interference signal, and sending the interference signal to the spectrometer for signal analysis to obtain a fault image;

the polarization controller is an optical fiber device and is used for changing the polarization state of light in the optical fiber by twisting and stretching the optical fiber;

the optical fiber pigtail is a light connector which is used as an interface between the interferometer and the sample arm light path and the reference arm light path respectively.

The reference arm optical path consists of a second collimating mirror, a dispersion compensation rod, a right-angle reflecting mirror and a delay reflecting mirror, and has the function of forming reference light with the same optical path as the sample arm optical path so as to form an interference signal with the return light of the sample arm.

And the second collimating lens is an optical lens, the focal length range is 5 mm-25 mm, and the numerical aperture is not more than 0.5.

The dispersion compensation rod is an optical device made of optical glass and has the function of compensating dispersion difference between a reference arm light path and a sample arm light path, and interference signals can reach the maximum value.

The right-angle reflecting mirror is an optical reflecting mirror, can reflect light rays incident on the right-angle reflecting mirror in a direction of 180 degrees, has the reflectivity of not less than 80 percent, and is used for folding a light path and reducing the volume of the light path of the reference arm.

The delay reflector is an optical reflector, the reflectivity is not lower than 90%, the delay reflector is used for reflecting incident light and forming reference light with the same optical path as the sample arm optical path, and the delay reflector can move back and forth along the optical axis and is used for compensating the difference of the length of the eye axis among different people.

The spectrometer is used for carrying out Fourier change on the formed interference signal to obtain a fault image.

The invention has the advantages and positive effects that:

1. the large-visual-field retina examination device adopts the illumination module with high integration level, and utilizes the annular condenser to converge light rays on the crystal and form a light ring, so that the light rays can be uniformly dispersed at the fundus to form fundus illumination of a visual field of more than 130 degrees. The illumination field is determined by the light-emitting angle of the light source, and is increased along with the increase of the light-emitting angle of the light source. The invention removes the light guide optical fiber and the light guide prism used in the prior art, and reduces the manufacturing cost and the installation and adjustment difficulty; the LED light source is used for replacing a halogen lamp light source, so that the power consumption and the heat productivity of the product are greatly reduced.

2. The large-view retina examination device integrates the fundus imaging light path with a large view field and the sample arm light path of optical coherence tomography imaging into one probe, thereby realizing the function of performing optical coherence tomography imaging on the fundus while performing real-time large-view field color imaging or fluorescence contrast imaging on the fundus. The two imaging modes are not interfered with each other, so that the comprehensive screening of the single device on the fundus diseases is realized, and the method is particularly suitable for the early diagnosis and the postoperative reexamination of the infant fundus retinopathy.

3. The large-view-field fundus imaging optical path of the large-view-field retina examination device realizes fluorescence radiography imaging by adopting a mode of optical filter switching, and solves the problem that a probe needs to be replaced in the prior art. Moreover, the probe realized by the invention has the characteristic of high integration, and has obvious advantages in volume and weight compared with the prior art.

Drawings

FIG. 1 is a schematic diagram of an optical structure of the present invention;

FIG. 2 is a schematic view of the direction of light rays of the illumination module in human eyes according to the present invention;

FIG. 3 is a color fundus image obtained by the present invention;

FIG. 4 is a fluorescence contrast image obtained by the present invention;

fig. 5 is an optical coherence tomographic image obtained by the present invention.

Detailed Description

The following detailed description of specific embodiments of the invention is provided in conjunction with the accompanying drawings:

the device of the embodiment mainly comprises a probe and an interferometer. As shown in figure 1, the probe consists of an illumination module, a fundus imaging optical path and a sample arm optical path.

The illumination module comprises an LED light source 3, a light homogenizing sheet 2 and an annular collecting lens 1, wherein the annular collecting lens is a ring with the diameter of 12mm formed by alternately arranging 8 white LEDs and 8 blue LEDs which are packaged in the same way, and the annular light homogenizing sheet is arranged in front of the annular collecting lens. When the LED light source emits light, the dodging sheet can be regarded as an annular luminous body with uniform brightness in all directions. An annular condenser lens is arranged in front of the dodging sheet, and light can pass through a contact lens of the contact lens group and be projected on the surface of the human eye lens 26 to form a light ring. These rays continue to travel forward and will spread out at the fundus to form a uniform illumination, as shown in figure 2. Since the central region 27 of the crystal is not illuminated by light rays 28, reflection of the illumination light into the fundus imaging optical path to form stray light can be avoided.

The fundus imaging light path is composed of a contact lens group, an imaging objective lens 8, a dichroic mirror 9, a low-pass filter 10, a fluorescent filter 25 and an imaging camera 24. The light emitted by the illumination module is reflected by the eyeground and collected by the ocular lens group, and an intermediate image surface R is formed behind the ocular lens group. The imaging objective lens performs secondary imaging on the intermediate image plane, and a final fundus image R' is formed on the imaging camera through the dichroic mirror and the low-pass filter.

The sample arm optical path is composed of a connecting eyepiece group, an imaging objective lens, a dichroic mirror, a high-pass filter 11, a scanning objective lens 13, a scanning galvanometer 14 and a first collimating lens 15, wherein the connecting eyepiece group, the imaging objective lens, the dichroic mirror and an eyeground imaging optical path are shared. The first collimating lens bends the light emitted by the optical fiber tail fiber of the interferometer into parallel light, and the parallel light is projected onto the scanning objective lens through the scanning galvanometer, and the scanning objective lens converges the light on the back focal plane to form a light spot. The scanning galvanometer can periodically change the reflection angle, so that the position of the light spot on the focal plane can also change along with the change of the reflection angle, and a scanning image surface R' is formed. R ' is optically conjugated with the middle image plane R ' through the high-pass filter, the dichroic mirror and the imaging objective lens, and R ' is optically conjugated with the eye fundus of the human eye through the ocular lens group, so that the scanning image plane R ' is also optically conjugated with the eye fundus of the human eye, and then a light spot on R ' is also a light spot at the eye fundus of the human eye. Thus, the light spot can be scanned over the fundus by changing the reflection angle of the scanning galvanometer. The eyeground reflects the light point, and the light returns to the optical fiber pigtail through the sample arm optical path and enters the interferometer.

The LED light source is a surface mount LED, the white light LED is a color imaging light source, the color temperature range is 5000K, and the color rendering index is 92%; the blue light LED is a fluorescence contrast light source, and the central wavelength is 475 nm.

The light homogenizing sheet is an acrylic sheet with two frosted surfaces, the surface roughness is 300 meshes, and the light transmittance is 80%.

The annular condenser is an optical lens, one surface of the annular condenser is a plane, the curvature radius range of the other surface of the annular condenser is 6.5mm, and the annular condenser is made of PMMA.

The ocular lens group consists of a contact lens 5, a conical lens 6 and an ocular objective lens 7, and is used for collecting light rays reflected by the eyeground to form a middle image surface R with good quality and low distortion.

The contact lens is an optical lens and needs to be in contact with the cornea 4 of the human eye during work. Therefore, the curvature radius is 8mm close to that of human cornea, and the material is ZLAF optical glass.

The conical lens is a conical optical lens made of LaK series optical glass and combined with the contact lens to eliminate chromatic aberration of a part of human eyes. The diameter of the gluing part of the conical lens and the contact lens is 5mm, and the cone angle is 40 degrees, so that enough installation space can be provided for the lighting module.

The objective lens is 2 optical lenses, which is used for eliminating aberration of human eyes, mainly spherical aberration, coma aberration, chromatic aberration and distortion, wherein one of the optical lenses is a double-cemented lens.

The imaging objective lens is 3 optical lenses, the combined focal length range is 30mm, the imaging objective lens comprises 1 double-cemented lens and 1 triple-cemented lens, and the imaging objective lens is used for eliminating chromatic aberration and secondary chromatic aberration of human eyes. The imaging objective lens can move back and forth along the imaging optical axis and is used for compensating the individual difference of the diopter of human eyes, so that the imaging image surface R' just falls on the imaging camera to form a clear fundus retina image, as shown in figure 3. Moreover, the imaging objective lens also has the image space telecentricity characteristic, and the telecentricity is 1.5 degrees.

The dichroic mirror is an optical transflective mirror, and the working angle is 45 degrees. The function of the lens is to reflect visible light and transmit near infrared light, and the visible light and the near infrared light are transmitted in mutually perpendicular directions after passing through the lens, so that the aim of separation is fulfilled.

The low-pass filter is an optical filter, and the working angle is 0 degree. The function of the device is to cut off near infrared light while transmitting visible light, so as to prevent the near infrared light from entering an imaging camera to interfere with an image.

The fluorescence filter is an optical filter, and the working angle is 0 degree. The function of the fluorescence imaging device is to transmit green fluorescence excited by the blue light irradiating fluorescein and cut off light of other wave bands to form a fluorescence contrast image with high contrast, as shown in fig. 4.

The low-pass filter and the fluorescence filter can be switched by a mechanical structure, and only one of the low-pass filter and the fluorescence filter can be in the fundus imaging optical path at a time. When the fundus is subjected to color imaging, a low-pass filter is used; and when fluorescence contrast imaging is performed on the fundus, a fluorescence filter is used.

The imaging camera is a CMOS camera, has a photosensitive area of 1/1.8 inch and a resolution of less than 300 ten thousand pixels, and is positioned on an image plane R' of a fundus imaging optical path to form an image.

The first collimating lens is an optical lens, the focal length range is 7.5mm, and the numerical aperture is 0.3.

The scanning galvanometer is a scanning reflector, the reflection angle can be periodically changed, the scanning frequency is 1KHz, and the scanning angle is not more than +/-10 degrees.

The scanning objective lens is 5 optical lenses, and the combined focal length range is 50 mm. The scanning objective lens also has the characteristics of image space telecentricity and low distortion, wherein the telecentricity is 1 degree, and the distortion is 3 percent.

The high-pass filter is an optical filter, and the working angle is 0 degree. The near infrared light is transmitted and the visible light is cut off, so that the interference caused by the visible light entering the interferometer due to the reflection of the eyeground is avoided.

The interferometer consists of a weak coherent light source 20, a 2x2 optical fiber coupler 19, a polarization controller 17, a fiber pigtail 16, a reference arm optical path and a spectrometer 21 and is used for carrying out optical coherence tomography on the retina of the eye.

The optical weak coherent light source is a super-radiation light emitting diode (SLED), the central wavelength of the SLED is 850nm, and the bandwidth of the SLED is 60 nm.

The 2x2 optical fiber coupler is an optical fiber device and is a core device of the interferometer. The spectrometer is provided with 4 tail fibers which are respectively connected into a weak coherent light source, a sample arm light path, a reference arm light path and a spectrometer. The interferometer has the functions of respectively guiding light rays emitted by the weak coherent light source into the sample arm light path and the reference arm light path according to a certain proportion, collecting return light of the two light paths to form an interference signal, and sending the interference signal into the spectrometer for signal analysis to obtain a tomographic image.

The polarization controller is a double-paddle dial plate type, the diameters of the two paddle plates are both 22mm, two 1/4 wave plates aiming at the 840nm light source are formed according to the number of turns of winding of the optical fiber, and the polarization state of light in the optical fiber can be adjusted at will.

The reference arm optical path is composed of a second collimating mirror 18, a dispersion compensation rod 12, a right-angle reflecting mirror 23 and a delay reflecting mirror 22, and the function of the reference arm optical path is to form reference light with the same optical path as that of the sample arm and form interference signals with return light of the sample arm.

The second collimating lens is an optical lens, the focal length range is 7.5mm, and the numerical aperture is 0.3.

The dispersion compensation rod is an optical device, is made of K9 glass and has a length of 30 mm. The function of the method is to compensate the dispersion difference between the reference arm optical path and the sample arm optical path and ensure that the interference signal can reach the maximum value.

The right-angle reflecting mirror is an optical reflecting mirror, and can reflect light rays incident on the right-angle reflecting mirror in a direction of 180 degrees, wherein the reflectivity is 92%. The function of the optical path is to fold the optical path and reduce the volume of the optical path of the reference arm.

The delay reflector is an optical reflector, and the reflectivity is 98%. The function of the optical path is to reflect the incident light and form the reference light with the same optical path length as the optical path of the sample arm. The delay mirror can move back and forth along the optical axis to compensate for the difference in length of the eye axis between different persons.

The spectrometer is used for performing fourier transform on the formed interference signal to obtain a tomographic image, as shown in fig. 5.

Although the embodiments of the present invention and the accompanying drawings are disclosed for illustrative purposes, those skilled in the art will appreciate that: various substitutions, changes and modifications are possible without departing from the spirit and scope of the invention and the appended claims, and therefore the scope of the invention is not limited to the disclosure of the embodiments and the accompanying drawings.

Claims

1. A large-field retinal examination device characterized by: the interferometer is connected with a sample arm light path in the probe through an optical fiber pigtail in the interferometer;

2. A large-field retinal examination device according to claim 1, wherein: the length of the probe is not more than 250mm, and the weight of the probe is not more than 3 kg.

3. A large-field retinal examination device according to claim 1, wherein: the probe consists of an illumination module, an eyeground imaging optical path and a sample arm optical path,

the illumination module comprises LED light sources, light homogenizing sheets and annular condensing lenses, wherein the LED light sources are arranged in a circular ring shape, the annular light homogenizing sheet is arranged in front of the formed circular ring, the annular condensing lenses are arranged in front of the light homogenizing sheet, and the annular condensing lenses project light rays on the surface of the intraocular lens after passing through contact lenses of the contact lens group to form a light ring;

the fundus imaging light path is composed of an ocular lens group, an imaging objective lens, a dichroic mirror, a low-pass filter, a fluorescent filter and an imaging camera, light rays emitted by the illumination module are collected by the ocular lens group after being reflected by the fundus and form a middle image surface R behind the ocular lens group, the imaging objective lens can carry out secondary imaging on the middle image surface, and a final fundus image R' is formed on the imaging camera through the dichroic mirror, the low-pass filter or the fluorescent filter;

4. A large-field retinal examination device according to claim 3, wherein: the LED light source is a surface mount LED and consists of white light LEDs and blue light LEDs which are arranged at intervals, the white light LEDs are color imaging light sources, the color temperature range is 4000K-5500K, and the color rendering index is not lower than 90%; the blue light LEDs are fluorescence contrast light sources, the central wavelength range is 460 nm-490 nm, and the number of each LED is not less than 6;

the light homogenizing sheet is an acrylic plate or ground glass with a frosted surface, the surface roughness is not less than 1000 meshes, and the light transmittance is not less than 70%;

the annular condenser is an optical lens, one surface of the annular condenser is a plane, and the curvature radius of the other surface of the annular condenser ranges from 2mm to 10 mm.

5. A large-field retinal examination device according to claim 3, wherein: the ocular lens group consists of a contact lens, a conical lens and an ocular objective lens and is used for collecting light rays reflected by the eyeground to form an intermediate image surface R;

the contact lens is an optical lens, and the curvature radius of the contact lens is similar to that of the cornea of human eyes;

the conical lens is a conical optical lens, the material of the conical lens is different from that of the contact lens, the conical lens and the contact lens form a cemented lens for eliminating part of chromatic aberration of human eyes, and the illumination module is arranged on the outer ring of the conical lens;

6. A large-field retinal examination device according to claim 3, wherein: the imaging objective lens is 1 group of optical lenses, the focal length range is 10-100 mm, and at least comprises 1 cemented lens, the imaging objective lens moves back and forth along the imaging optical axis and is used for compensating the individual difference of the diopter of human eyes, so that an imaging image surface R' just falls on the imaging camera to form a clear fundus retina image;

the dichroic mirror is an optical transflective mirror, the working angle is 45 degrees, and the dichroic mirror has the function of reflecting visible light and transmitting near infrared light at the same time, so that the visible light and the near infrared light are transmitted in mutually perpendicular directions after passing through the mirror, and the purpose of separation is achieved;

the low-pass filter is an optical filter, the working angle is 0 degree, and the low-pass filter has the function of cutting off near infrared light while transmitting visible light, so that the near infrared light is prevented from entering an imaging camera to form interference on an image;

the fluorescence filter is an optical filter, the working angle is 0 degrees, and the fluorescence filter has the functions of transmitting green fluorescence excited by irradiating fluorescein by blue light and cutting off light of other wave bands to form a fluorescence contrast image with high contrast;

7. The wide field retinal examination device according to claim 6, wherein: the low-pass filter and the fluorescent filter are switched for use, and the low-pass filter is used when only one of the low-pass filter and the fluorescent filter can be used for carrying out color imaging on the fundus in an fundus imaging optical path each time; when fluorescence radiography imaging is performed on the fundus, a fluorescence filter is used.

8. A large-field retinal examination device according to claim 1, wherein: the first collimating lens is an optical lens, the focal length range is 5-25 mm, and the numerical aperture is not more than 0.5;

the scanning galvanometer is a scanning reflector, the reflection angle can be periodically changed, the scanning frequency is not lower than 100Hz, and the scanning angle is not more than +/-20 degrees;

the scanning objective lens is 1 group of optical lenses, and the focal length range is 20 mm-100 mm;

9. A large-field retinal examination device according to claim 1, wherein: the interferometer consists of a weak coherent light source, a 2x2 optical fiber coupler, a polarization controller, an optical fiber pigtail, a reference arm optical path and a spectrometer,

the optical fiber pigtail is a light connector and is used as an interface between the interferometer and a sample arm light path and a reference arm light path respectively;

10. A large field of view retinal examination device according to claim 9, wherein: the second collimating lens is an optical lens, the focal length range is 5-25 mm, and the numerical aperture is not more than 0.5;

the dispersion compensation rod is an optical device made of optical glass and has the function of compensating dispersion difference between a reference arm light path and a sample arm light path to ensure that an interference signal can reach the maximum value;

the right-angle reflecting mirror is an optical reflecting mirror, can reflect light rays incident on the right-angle reflecting mirror in a direction of 180 degrees, has the reflectivity of not less than 80 percent, and is used for folding a light path and reducing the volume of the light path of the reference arm;

the delay reflector is an optical reflector, the reflectivity is not lower than 90%, the delay reflector is used for reflecting incident light and forming reference light with the same optical path as the sample arm optical path, and the delay reflector can move back and forth along the optical axis and is used for compensating the difference of the length of the eye axis among different people;