Fundus camera optical system with aperture and fundus camera

Abstract

The present disclosure relates to an optical system of a fundus camera with a light barrier, which comprises an illumination device, a first optical assembly, a second optical assembly, an imaging device and a positioning device; the illumination device comprises an illumination light source; the first optical assembly comprises a first half-transmission half-reflection mirror, a first polarizer, a second half-transmission half-reflection mirror and a retinal objective lens, the first optical assembly directs the light beam from the illumination light source to the fundus of the eye to be examined, and guides the reflected light of the fundus to the second optical assembly; the second optical assembly comprises a second polarizer and a focusing module, the focusing module guides the reflected light to the imaging device; the imaging device receives the light from the second optical assembly to form the fundus image; the positioning device comprises a guiding light source and a light barrier, the light beam of the guiding light source has a preset shape after passing through the light barrier, the imaging device acquires the fundus images of different regions of the eye to be examined based on the guiding light source, and the first optical assembly directs the light beam of the guiding light source to the fundus of the eye to be examined for imaging.

Description

[0001] This application is a divisional application of patent application No. 201911209363.5, filed on December 1, 2019, entitled "Optical System for Fundus Camera and Fundus Camera". Technical Field

[0002] This disclosure relates to the field of medical device technology, specifically to an optical system for a fundus camera with an aperture and a fundus camera. Background Technology

[0003] The retina at the back of the human eye contains a large number of capillaries. When patients suffer from diseases such as diabetes, glaucoma, macular degeneration, and hypertension, it can cause damage to the capillaries in the retina. Medical professionals can determine whether a patient has these diseases by observing the microvascular network in the retina.

[0004] Currently, in actual clinical diagnosis, medical staff usually use fundus cameras to obtain images of the patient's fundus to obtain the patient's diagnostic results.

[0005] Most existing fundus cameras consist of an illumination system and an imaging system. The illumination system provides illumination light, which, upon reaching the fundus of the human eye, produces reflected light. This reflected light then passes through the imaging system to form a fundus image.

[0006] For example, Patent Document 1 (Patent Application Publication No. CN105581771A) discloses a fundus camera that includes a fixation light source. In the fundus camera of Patent Document 1, the image sensing element and the fixation light element are located on the equivalent focal plane of the imaging lens group by means of optical elements. The fixation light element and the image sensing element share an imaging system to incident the fixation light source into the fundus of the eye.

[0007] However, in the aforementioned patent document 1, the fixation light source and image sensing element of the fundus camera use the same optical path, resulting in weaker reflected light from the fundus of the human eye compared to reflected light from the cornea, and a large amount of stray light is generated when the fundus camera takes pictures. Summary of the Invention

[0008] This disclosure is made in view of the above-mentioned situation, and its purpose is to provide an optical system and a fundus camera that can reduce stray light generated when photographing the fundus of the examined eye.

[0009] Therefore, this invention discloses an optical system for a fundus camera, characterized by comprising: an illumination device having an illumination source; a first optical component having a first semi-transparent mirror, a first polarizer, a second semi-transparent mirror, and a retinal objective lens, wherein the first polarizer is used to convert the light beam received by the first semi-transparent mirror from the illumination source into first polarized light having a first polarization state; the second semi-transparent mirror is used to reflect the first polarized light to the retinal objective lens; the retinal objective lens is used to guide the received first polarized light to the fundus of the examined eye and receive the reflected light from the fundus; the second semi-transparent mirror is used to receive the reflected light passing through the retinal objective lens and guide it to the second optical component; the second optical component has a second polarizer and a focusing module, wherein the second... A polarizer is used to obtain second polarized light with a second polarization state using the reflected light. The focusing module guides the second polarized light to an imaging device. The imaging device receives the second polarized light to form a fundus image. A positioning device has multiple guiding light sources, which guide the line of sight of the examined eye. The imaging device acquires fundus images of different regions of the examined eye based on the guiding light sources. The first optical component guides the light beam received by the first semi-transparent mirror from the guiding light sources to the fundus of the examined eye for imaging. The polarization direction of the first polarization state is orthogonal to the polarization direction of the second polarization state. The retinal objective lens and the focusing module share the same optical axis. The second semi-transparent mirror is placed at a 45-degree angle to the optical axis.

[0010] In this disclosure, the light beam provided by the illumination source in the illumination device passes through a first polarizer to form first polarized light with a first polarization state. The first polarized light enters the examined eye and is reflected from the fundus to generate reflected light. The reflected light passes through a second polarizer to form second polarized light with a second polarization state, and the second polarized light reaches the imaging device to form a fundus image. In this case, the first polarized light is reflected at the retinal objective and the cornea of ​​the examined eye to generate stray light with a first polarization state, which can be filtered out by the second polarizer. Thus, stray light mixed in with the reflected light from the fundus can be filtered out by the second polarizer, resulting in a clearer fundus image.

[0011] In the optical system of the fundus camera disclosed herein, optionally, the positioning device includes a lens, with the plurality of guiding light sources located at or near the focal point of the lens, and the light beams of the guiding light sources passing through the lens to reach the first semi-transparent mirror. In this case, the light beam passing through the lens can be made parallel.

[0012] In the optical system of the fundus camera disclosed herein, optionally, the illumination device has a homogenizing filter that homogenizes the light beam from the illumination source. In this case, the light beam after passing through the homogenizing filter becomes uniform.

[0013] In the optical system of the fundus camera disclosed herein, optionally, the light-diffusing filter has a conjugate relationship with the pupil of the examined eye. In this case, a uniform light spot can be formed at the pupil of the examined eye.

[0014] In the optical system of the fundus camera disclosed herein, optionally, the illumination device includes a field stop for adjusting the size of the light spot on the pupil. In this case, the size of the light beam emitted by the illumination device can be controlled.

[0015] In the optical system of the fundus camera disclosed herein, the retinal objective assembly optionally includes at least a cemented lens. In this case, partial chromatic aberration can be eliminated.

[0016] In the optical system of the fundus camera disclosed herein, optionally, the focusing module includes a focusing group and a first aperture stop, the focusing group being located near the second polarizer. In this case, the focusing group and the first aperture stop can be adjusted to achieve clear imaging subsequently.

[0017] In the optical system of the fundus camera disclosed herein, optionally, the distance between the focusing group and the second polarizer is adjustable. In this case, it is possible to achieve focusing on examiner eyes with different refractive powers.

[0018] In the optical system of the fundus camera disclosed herein, optionally, the pupil of the examined eye has a conjugate relationship with the first aperture stop. In this case, the influence of the pupil of the examined eye on the fundus image acquired by the imaging device 14 can be avoided.

[0019] This disclosure relates to a fundus camera, characterized in that it includes: an optical system of the fundus camera as described in any of the preceding claims; and an external device connected to the imaging device, wherein the external device further includes: a control module for controlling the movement of optical elements within the first optical component and the second optical component; and an information processing module for processing imaging information captured by the imaging device.

[0020] In this disclosure, the light beam provided by the illumination source in the illumination device passes through a first polarizer to form first polarized light with a first polarization state. This first polarized light enters the examined eye and is reflected from the fundus to generate reflected light. The reflected light passes through a second polarizer to form second polarized light with a second polarization state. This second polarized light reaches the imaging device to form a fundus image. The imaging device is connected to an external device. In this external device, a control module can control the distance between the focusing group in the focusing module and the second polarizer to achieve focusing. In this configuration, the imaging device can obtain a relatively clear fundus image. Simultaneously, the information processing module can store, transform, transmit, and display the imaging information captured by the imaging process.

[0021] Compared with the prior art, the present disclosure can reduce stray light generated by the cornea during shooting, obtain clearer fundus images, and simplify the structure of the fundus camera and its optical system. Attached Figure Description

[0022] Embodiments of this disclosure will now be explained in further detail by way of example only with reference to the accompanying drawings, in which:

[0023] Figure 1 This is a schematic diagram illustrating the application scenarios of the fundus camera involved in this disclosure.

[0024] Figure 2 This is a schematic diagram showing the modular framework of a fundus camera involved in this disclosure.

[0025] Figure 3 This is a schematic diagram showing the modular framework of the optical system of the fundus camera involved in this disclosure.

[0026] Figure 4 This is a schematic diagram illustrating the illumination device of the fundus camera involved in this disclosure.

[0027] Figure 5 This is a schematic diagram illustrating a modified example of the illumination device of the fundus camera involved in this disclosure.

[0028] Figure 6 This is a schematic diagram showing the illumination source of the illumination device of the fundus camera involved in this disclosure.

[0029] Figure 7 This is a schematic diagram showing the first optical component of the optical system of the fundus camera involved in this disclosure.

[0030] Figure 8 This is a schematic diagram showing a second optical component in the optical system involved in this disclosure.

[0031] Figure 9 This is a schematic diagram showing the positioning device of the fundus camera involved in this disclosure.

[0032] Figure 10 This is a schematic diagram showing the guide light source of the positioning device involved in this disclosure.

[0033] Figure 11 This is a schematic diagram showing the module frame of the peripheral device of the fundus camera involved in this disclosure.

[0034] Explanation of main icon numbers:

[0035] 1…Fundus camera, 10…Optical system, 11…Illumination device, 12…First optical component, 13…Second optical component, 14…Imaging device, 15…Positioning device, 16…Optical axis, 17…Peripheral device, 2…Examined eye, 21…Fundus, 22…Cornea. Detailed Implementation

[0036] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same parts, and repeated descriptions are omitted. Furthermore, the drawings are merely schematic diagrams, and the proportions of the parts or the shapes of the parts may differ from the actual figures.

[0037] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this disclosure are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0038] Furthermore, the subheadings and similar terms used in the following description of this disclosure are not intended to limit the content or scope of this disclosure; they are merely intended to serve as reading prompts. Such subheadings should not be construed as dividing the content of the article, nor should the content under a subheading be limited to the scope of that subheading.

[0039] Figure 1 This is a schematic diagram illustrating an application scenario of the fundus camera involved in this disclosure. In this embodiment, as... Figure 1 As shown, fundus camera 1 is a handheld fundus camera. Medical staff can obtain fundus images of the patient's examined eye 2 by operating fundus camera 1 with one or both hands.

[0040] Figure 2 This is a schematic diagram illustrating the module frame of a fundus camera according to this disclosure. In this embodiment, as... Figure 2 As shown, the fundus camera 1 may include an optical system 10 and a peripheral device 17. The optical system 10 of the fundus camera 1 is capable of acquiring clear fundus images of the examined eye 2. The peripheral device 17 is capable of controlling some optical components in the optical system 10 of the fundus camera 1 and processing the fundus images acquired by the optical system 10 of the fundus camera 1. In addition, the optical system 10 of the fundus camera 1 according to this embodiment may be simply referred to as the optical system 10.

[0041] Figure 3This is a schematic diagram of the module framework of the optical system 10 of the fundus camera 1 involved in this disclosure. In this embodiment, as... Figure 3 As shown, the optical system 10 of the fundus camera 1 may include an illumination device 11, a first optical component 12, a second optical component 13, and an imaging device 14. The light beam generated by the illumination source of the illumination device 11 can be incident on the examined eye 2 through the first optical component 12, and reflected at the fundus of the examined eye 2 to generate reflected light. The reflected light then passes through the first optical component 12 and the second optical component 13 to reach the imaging device 14.

[0042] Figure 4 This is a schematic diagram showing the illumination device 11 of the fundus camera 1 according to this disclosure. In this embodiment, as... Figure 4 As shown, the lighting device 11 may include a lighting source 111. The lighting source 111 may be a single-spectrum light source. In some examples, the lighting source 111 may be a multi-spectral light source.

[0043] In some examples, such as Figure 4 As shown, the lighting device 11 may include a light diffuser 112 (also referred to as a light homogenizer). The light diffuser 112 can receive the light beam emitted by the lighting source and homogenize the light beam from the lighting source. In this case, the light beam after passing through the light diffuser can become uniform.

[0044] In some examples, the light-diffusing plate 112 has a conjugate relationship with the pupil of the examined eye 2. That is, the image plane of the light beam emitted from the light-diffusing plate 112 has a conjugate relationship with the pupil image formed in the examined eye 2. In this case, a uniform light spot can be formed at the pupil of the examined eye 2. In other words, the light spot emitted from the light-diffusing plate 112 can form an image in the pupil of the examined eye 2.

[0045] In some examples, the light diffuser 112 can be thin. For example, the thickness of the light diffuser 112 can be selected from 0.05 mm to 60 mm. The light beam emitted through the thin light diffuser 112 can be evenly distributed and the light energy utilization rate can be improved. However, the examples of this disclosure are not limited to this; for example, the thickness of the light diffuser 112 can be greater than 60 mm.

[0046] In some examples, the lighting device 11 may include a first lens 113. The first lens 113 may be located between the lighting source 111 and the diffuser 112. The light beam emitted from the lighting source 111 can be formed into a parallel light beam by passing through the first lens 113.

[0047] In this embodiment, the first lens 113 of the illumination device 11 can be a convex lens. The illumination source 111 can be placed at the focal point of the convex lens. However, this embodiment is not limited to this; for example, the first lens 113 can be an optical instrument composed of multiple lenses. This optical instrument can guide the light beam emitted by the illumination source 111 into a parallel light beam.

[0048] Figure 5 This is a schematic diagram illustrating a modified example of the illumination device 11 of the fundus camera 1 according to this disclosure. In some examples, the number of illumination sources 111 can be multiple. For example... Figure 5 As shown, the lighting device 11 may include two light sources and a third semi-transparent mirror 114, such as a first light source 111a and a second light source 111b. The beams emitted by the multiple light sources can be combined into a single beam by the third semi-transparent mirror 114. The third semi-transparent mirror 114 may be a beam splitter or beam splitter prism for splitting the beams of the first light source 111a and the second light source 111b. In some examples, the beam combined by the third semi-transparent mirror 114 may contain half of the beam from each light source. In other examples, the beam combined by the third semi-transparent mirror 114 may contain the spectrum of one of the light sources, either the first light source 111a or the second light source 111b, as the dominant transmitted light.

[0049] In some examples, such as Figure 5 As shown, the light beams emitted from the first illumination source 111a and the second illumination source 111b can be formed into two parallel light beams by passing through the first lens 113a and the first lens 113b, respectively. The parallel light beams emitted from the first lens 113a or the first lens 113b can pass through the first light diffuser 112a and the second light diffuser 112b, respectively, to reach the third semi-transparent and semi-reflective mirror 114.

[0050] In some examples, the light beams emitted from the first illumination source 111a and the second illumination source 111b can pass directly through the first light diffuser 112a and the second light diffuser 112b to reach the third semi-transparent mirror 114 without the first lens 113a and the first lens 113b.

[0051] In some examples, the first light diffuser 112a and the second light diffuser 112b can be placed symmetrically about the third semi-transparent mirror 114.

[0052] In other examples, the lighting device 11 may provide three or more light sources 111.

[0053] In some examples, when the lighting device 11 has multiple light sources, each light source can work simultaneously or individually.

[0054] In some examples, the illumination source 111 can be a ring light source. In this case, stray light generated at the cornea can be reflected outside the imaging optical path (i.e., the transmission optical path of the reflected light from the fundus), thereby reducing stray light mixed in with the reflected light from the fundus.

[0055] Figure 6 This is a schematic diagram showing the illumination source 111 of the illumination device 11 of the fundus camera 1 according to this disclosure. In some examples, such as Figure 6 As shown, the illumination source 111 can be composed of multiple illumination sub-sources 1111. The illumination source 111 can be composed of a single monochromatic illumination sub-source 1111. For example, the illumination source 111 can be composed of visible yellow light as the illumination sub-source 1111.

[0056] However, this embodiment is not limited to this. The lighting source 111 may be composed of two or more monochromatic LEDs forming a lighting sub-light source 1111. For example, the lighting source 111 may be a white light source formed by mixing two wavelengths of blue light and yellow light. The lighting source 111 may also be a white light source formed by mixing three wavelengths of blue light, green light and red light.

[0057] Additionally, in some examples, the lighting source 111 can be an LED cold light source. Therefore, using an LED cold light source 111 can reduce the operating power of the lighting device 11, reduce heat generation, decrease the size of the lighting device 11, and increase its lifespan. In this embodiment, as... Figure 6 As shown, the plurality of illumination sub-light sources 1111 can be ring-shaped. However, this embodiment is not limited to this; the plurality of illumination sub-light sources 1111 of the illumination source 111 can also be, for example, tiled or rectangular.

[0058] In some examples, the illumination device 11 may include a field stop (not shown). The field stop has a conjugate relationship (i.e., object-image relationship) with the pupil of the examined eye 2. The field stop can be used to adjust the size of the light spot on the pupil of the examined eye 2. That is, the size of the light beam from the illumination source 111 can be adjusted by the field stop.

[0059] In some examples, the illumination device 11 may include a second lens (not shown). When the illumination device 11 has only one illumination source (e.g., illumination source 111), the diffuser 112 and the field stop form an image with respect to the second lens. When the illumination device 11 has multiple illumination sources (e.g., first illumination source 111a and second illumination source 111b), each diffuser (e.g., first diffuser 112a and second diffuser 112b) forms an image with respect to the second lens and the field stop.

[0060] In some examples, when the lighting device 11 has only one light source (e.g., light source 111), the light beam emitted from the diffuser 112 passes through the second lens and reaches the field stop. When the lighting device 11 has multiple light sources, such as the first light source 111a and the second light source 111b, the light beam synthesized by the third semi-transparent mirror 114 passes through the second lens and reaches the field stop.

[0061] In some examples, the illumination device 11 may include a lens group and a second aperture stop. The light beam passing through the field stop passes sequentially through the lens group and the second aperture stop to reach the first optical component 12 (described in detail later).

[0062] Figure 7 This is a schematic diagram showing the first optical component 12 of the optical system 10 of the fundus camera 1 involved in this disclosure. Figure 7 As shown, the first optical component 12 can project a light beam from the illumination source of the illumination device 11 onto the fundus 21 of the eye being examined 2. In some examples, the first optical component 12 can guide the light beam of the guiding light source 151 of the positioning device 15 (described in detail later) to the eye being examined 2.

[0063] In this embodiment, such as Figure 7 As shown, the first optical component 12 may include a first polarizer 121. The first polarizer 121 can transmit a light beam having a first polarization state. Specifically, the first polarizer 121 can be used to convert a light beam from an illumination source of the illumination device 11 into first polarized light having a first polarization state. This embodiment is not limited thereto; for example, the first polarizer 121 may be replaced by an optical element including a polarizer capable of forming a light beam having a first polarization state, or it may be replaced by an optical device having the same or similar polarization function.

[0064] In some examples, such as Figure 7 As shown, the first optical component 12 may include a first semi-transparent mirror 122. The first semi-transparent mirror 122 can receive the light beam from the illumination source of the illumination device 11 and guide the light beam to the first polarizer 121. That is, the light beam from the illumination source of the illumination device 11 can pass through the first semi-transparent mirror 122 to reach the first polarizer 121.

[0065] In some examples, the first semi-transparent mirror 122 can be a beam splitter or a beam splitter prism.

[0066] In some examples, such as Figure 7 As shown, the first semi-transparent mirror 122 can couple the light beam from the illumination source of the illumination device 11 and the light beam from the positioning device 15, and guide the coupled light beam to the first polarizer 121. The first semi-transparent mirror 122 is disposed between the illumination device 11 and the first polarizer 121.

[0067] In some examples, the first semi-transparent mirror 122 can change the propagation direction of the guide light source of the positioning device 15. Specifically, the first semi-transparent mirror 122 can receive the light beam from the guide light source 151 of the positioning device 15 (see [link to documentation]). Figure 7 The light beam from the illumination source and the light beam from the guide light source are reflected so that they share a single optical path. That is, the light beam from the illumination source and the light beam from the guide light source share the first optical component 12. In this configuration, coaxial illumination and positioning can be achieved, and the use of optical components can be reduced, simplifying the structure of the fundus camera 1.

[0068] In other examples, the first semi-transparent mirror 122 can be replaced by an optical element that has a similar function to the first semi-transparent mirror 122 and is capable of changing the propagation direction of the beam from the guiding light source of the positioning device 15. For example, it can be a beam splitter, or a beam expander, lens, lens group, or other optical element group.

[0069] In some examples, the angle of the first semi-transparent mirror 122 is adjustable. In this case, the optical path structure in the optical system 10 can be simplified.

[0070] In some examples, when the fundus camera 1 does not include the positioning device 15, the first optical component 12 may not include the first semi-transparent mirror 122. In this case, the light beam from the illumination source of the illumination device 11 is directly received by the first polarizer 121. The examples in this disclosure are not limited thereto; when the fundus camera 1 does not include the positioning device 15, the first optical component 12 may include the first semi-transparent mirror 122.

[0071] In this embodiment, such as Figure 7 As shown, the first optical component 12 may include a second semi-transparent mirror 123. The second semi-transparent mirror can be used to receive first polarized light and reflect the first polarized light to the retina objective 124 (described in detail later). In some examples, the second semi-transparent mirror 123 may be substantially parallel to the first semi-transparent mirror 122.

[0072] In some examples, the second semi-transparent mirror 123 can be disposed between the first polarizer 121 and the second polarizer 131 (see [reference]). Figure 7 and Figure 8 Between ) . For example Figure 7 As shown, the second semi-transparent mirror 123 can be positioned at a certain angle to the optical axis 16 (described later) where the retinal objective lens 124 is located. The angle can be, but is not limited to, 40°, 45° or 50°.

[0073] In some examples, the second semi-transparent mirror 123 can be replaced by a beam splitter. The beam splitter can be an optical element with the same or similar function as the second semi-transparent mirror 123. The examples disclosed herein are not limited to this; the second semi-transparent mirror 123 can be replaced by a beam expander, a lens, a lens group, a polarizing beam splitter, an anti-polarizing beam splitter, or other optical element groups. Anti-reflective coatings can be provided on the polarizing beam splitter and the anti-polarizing beam splitter.

[0074] In some examples, such as Figure 7 As shown, the second semi-transparent mirror 123 can change the propagation direction of the first polarized light having a first polarization state, so that the light beam having the first polarization state and the reflected light from the fundus 21 share some optical elements (for example). As a result, the number of optical elements used can be reduced, and the structure of the fundus camera 1 can be simplified.

[0075] In this embodiment, such as Figure 7 As shown, the first optical component 12 may include a retinal objective lens 124 located between the second semi-transparent mirror 123 and the eye under examination 2. The retinal objective lens 124 may be used to guide the received first polarized light to the fundus 21 of the eye under examination 2 and receive the reflected light from the fundus 21.

[0076] In some examples, the retinal objective 124 may be a three-element retinal objective, thereby reducing the use of optical elements and reducing chromatic aberration caused by the light beam reflected from the fundus 21.

[0077] In this embodiment, one or more lenses 124a may be provided in the retinal objective lens 124. This improves the clarity of the transmitted light beam and makes the light beam more uniform.

[0078] In this embodiment, the retinal objective 124 may include a cemented lens 124b. The cemented lens may be formed by cementing two lenses of different materials together. This allows for the elimination of some chromatic aberration; specifically, it enables the correction of chromatic aberration in the three wavelengths of light: blue, green, and red.

[0079] In this embodiment, the retinal objective lens 124 can guide the first polarized light reflected by the second semi-transparent mirror 123 to the fundus 21 of the examined eye 2, and receive the reflected light from the fundus 21. The reflected light from the examined eye 2 passes through the retinal objective lens 124 and then through the second semi-transparent mirror 123 to reach the second optical component 13. That is, the second semi-transparent mirror 123 can be used to receive the reflected light passing through the retinal objective lens 124 and guide it to the second optical component 14.

[0080] In some examples, the first optical component 12 is able to direct the light beam received by the first semi-transparent mirror 122 from the guiding light source 151 to the fundus 21 of the examined eye 2 for imaging (described in detail later).

[0081] Figure 8 This is a schematic diagram showing the second optical component 13 in the optical system 10 according to this disclosure. In this embodiment, the second optical component 13 can guide reflected light passing through the second semi-transparent mirror 123 to the imaging device 14 (described later).

[0082] In this embodiment, such as Figure 8 As shown, the second optical component 13 may include a second polarizer 131. The second polarizer 131 can be used to obtain second polarized light with a second polarization state using reflected light. That is, reflected light passing through the second semi-transparent mirror 123 forms a beam with a second polarization state after passing through the second polarizer 131. The polarization direction of the second polarization state is orthogonal to that of the first polarization state. The polarization direction of the first polarization state can be S-polarized, and the polarization direction of the second polarization state can be P-polarized. However, the examples in this disclosure are not limited to this; the polarization direction of the first polarization state can be P-polarized, and the polarization direction of the second polarization state can be S-polarized.

[0083] In some examples, if the second semi-transparent mirror 123 in the first optical component 12 is a polarizing beam splitter, then the second optical component 13 may not include the second polarizer 131. In this case, the reflected light passing through the second semi-transparent mirror 123 can directly reach the focusing module. Specifically, when the second semi-transparent mirror 123 is a polarizing beam splitter, it can convert the reflected light into second polarized light with a second polarization state. In this case, the polarizing beam splitter can eliminate stray light. The first polarizer can then be connected to the surface of the polarizing beam splitter via a connector. The distance between the first polarizer and the surface of the polarizing beam splitter ranges from 0 to 100 mm.

[0084] In this embodiment, the second optical component 13 may include a focusing module. The focusing module guides the second polarized light to the imaging device 14. The second polarizer 131 and the second semi-transparent mirror 123 are located on the same side of the focusing module. The focusing module is located between the second polarizer 131 and the imaging device 14. In this case, the light beam having the second polarization state reaches the imaging device 14 through the focusing module.

[0085] In this embodiment, the retinal objective lens 124 may share the same optical axis 16 with the focusing module.

[0086] In this embodiment, such as Figure 8 As shown, the focusing module may include a focusing group 132 and a first aperture stop 134 arranged sequentially. The focusing group 132 is located near the second polarizer 131. In this configuration, the focusing group and the first aperture stop can be adjusted to achieve a clear image later.

[0087] In some examples, the focusing group 132 can move independently of the optical axis 16. The focusing group 132 may consist of one or more lenses. The distance between the focusing group 132 and the second polarizer 131 is adjustable. In this case, the focusing group 132 is adjusted to achieve focusing (i.e., refocusing) of the examined eye 2 with different diopters.

[0088] In daily life, due to differences in visual acuity in the examined eye 2, the refraction of light by the lens also varies, resulting in different images reaching the focusing group 132. In this embodiment, the lens base of the focusing group 132 is bound to a motor (not shown), and the focusing group 132 can be adjusted by controlling the sliding of the motor. This allows for control of the focal point of the light beam passing through the second polarizer 131, improving image clarity.

[0089] In some examples, the pupil of the examined eye 2 has a conjugate relationship with the first aperture stop 134. In this case, the pupil of the examined eye 2 can be clearly imaged inside the second optical component 13, and the first aperture stop 134 is positioned at the image plane of the pupil. This avoids the influence of the pupil of the examined eye 2 on the fundus image acquired by the imaging device 14 (described later), improving the reliability of the analysis results.

[0090] In some examples, the aperture size of the first aperture stop 134 is adjustable. Thus, by controlling the aperture size of the first aperture stop 134, the non-uniformity of the light beam passing through the focusing group 132 can be reduced, and stray light in the light beam passing through the focusing group 132 can be weakened, so that the imaging device 14 can obtain a clearer fundus image.

[0091] In this embodiment, such as Figure 8 As shown, the focusing module may further include a field lens 133 disposed between the focusing group 132 and the first aperture stop 134. The field lens 133 may consist of one or more lenses, thereby improving the image quality.

[0092] In this embodiment, such as Figure 8 As shown, the focusing module may further include a lens group 135 disposed between the first aperture stop 134 and the imaging device 14. The lens group 135 may consist of one or more lenses. Thus, by utilizing the lens group 135, the light emitted from the first aperture stop 134 can be better guided to the imaging device 14 to obtain a clear fundus image.

[0093] In this embodiment, the focusing module is located in the second optical component 13. When the tested eye 2 has different refractive power, the focusing module can be adjusted to enable the imaging device 14 to obtain a clear fundus image without affecting the optical path within the first optical component 12. In this case, the distance between the tested eye 2 and the imaging device 14 remains unchanged.

[0094] In this embodiment, the imaging device 14 can receive second polarized light to form a fundus image. Specifically, reflected light from the fundus 21 of the examined eye 2 passes through the retinal objective lens 124 and then through the second semi-transparent mirror 123 to reach the second optical component 13. The reflected light then passes through the second optical component 13 to form a fundus image at the imaging device 14. In addition, the imaging device 14 can acquire fundus images of different regions of the examined eye 2 based on a guide light source. That is, when the examined eye 2 gazes at different guide light sources, the imaging device 14 can capture fundus images of different regions of the fundus 21 of the examined eye 2.

[0095] In some examples, the imaging device 14 may be selected from photoelectric sensors such as CMOS image sensors or CCD image sensors. Photoelectric sensors can convert image information (light signals) into electrical signals.

[0096] In this disclosure, the light beam provided by the illumination source in the illumination device 11 passes through the first polarizer 121 to form first polarized light with a first polarization state. The first polarized light enters the examined eye 2 and is reflected at the fundus 21 to generate reflected light. The polarization state of the reflected light changes (e.g., the reflected light has no polarization state). The reflected light passes through the second polarizer 131 to form second polarized light with a second polarization state, and the second polarized light reaches the imaging device 14 to form a fundus image. In this case, the first polarized light is reflected at the retinal objective lens 124 and the cornea 22 of the examined eye 2 to generate stray light with a first polarization state, which can be filtered out by the second polarizer 131. Thus, stray light mixed in with the reflected light from the fundus can be filtered out by the second polarizer 131, resulting in a clearer fundus image.

[0097] In this embodiment, such as Figure 3 As shown, the optical system 10 may further include a positioning device 15. The positioning device 15 may provide multiple guiding light sources to guide the rotation of the examined eye 2. In other words, the positioning device 15 may have multiple guiding light sources. The guiding light sources may be used to guide the line of sight of the examined eye 2.

[0098] Figure 9 This is a schematic diagram showing the positioning device 15 of the fundus camera 1 according to this disclosure. In this embodiment, as... Figure 9 As shown, the positioning device 15 may include a guide light source 151 and a lens 152. The light beam from the guide light source 151 can reach the first semi-transparent mirror 122 through the lens 152. The light beam from the guide light source reflected by the first semi-transparent mirror 122 can pass through the first polarizer 121 to generate a light beam with a first polarization state.

[0099] In some examples, the guide light source 151 can be a single light source. The guide light source 151 can be positioned at the focal point of the lens 152. Thus, the light beam passing through the lens 152 can be parallel light. The light beam passing through the lens 152 passes through the aperture 153 to form the guide light source. The guide light source can guide the rotation of the examined eye 2. In some examples, the shape of the guide light source can be numbers, letters, or other patterns.

[0100] In some examples, there can be multiple guide light sources 151. These multiple guide light sources can be located at or near the focal point of the lens 152. This makes the light beam passing through the lens 152 parallel, that is, it makes the field of view of the light beam emitted at the aperture 153 smaller, thereby avoiding the need to include a focusing mechanism in the positioning device 15.

[0101] Figure 10 This is a schematic diagram showing the guide light source of the positioning device 15 according to this disclosure. The number of guide light sources 151 can be represented by a natural number n. In some examples, such as Figure 10 As shown, the number of guide light sources 151 can be 9.

[0102] In this embodiment, the guide light source 151 can be distributed in different locations. For example... Figure 10 As shown, one of the multiple guide light sources 151 is a guide light source 151. n As the center, other guiding light sources 151 n They are arranged in a circle. In other examples, the distribution of multiple guide lights 151 may also be in the shape of a cross, rectangle, etc.

[0103] In some examples, the number of lenses 152 can be one or more. The image plane of the guide light source exiting through the aperture 153 is a real image. The beam of the guide light source can be kept nearly parallel in the optical path so that the beam is focused on the fundus 21 of the examined eye 2 (see...). Figure 9 The image is clear.

[0104] In some examples, the positioning device 15 may include an aperture 153. The aperture 153 is located between the lens 152 and the first semi-transparent mirror 122. The guiding light source 151 can form uniform illumination after passing through the lens 152 and the aperture 153.

[0105] In some examples, there can be multiple apertures 153. The apertures 153 can be distributed in the desired shape, so that the guide light source formed by multiple apertures 153 can have the desired shape.

[0106] In other examples, the number of apertures 153 can be one. An aperture 153 can have n holes. Each hole can be of a desired shape. The n holes can be distributed in the desired shape. Thus, the guiding light source through the aperture 153 can have the desired shape.

[0107] In some examples, the color of the guide light source 151 may be a different color than that of the light source 111 of the lighting device 11. The light source 111 provided by the lighting device 11 is a white LED cold light, and the guide light source 151 may be a red LED, but the examples in this disclosure are not limited to this. For example, the light source 111 provided by the lighting device 11 is a white LED cold light, and the guide light source 151 may be a blue LED.

[0108] In some examples, a lens or lens group (not shown) may be disposed between the aperture 153 and the first semi-transparent mirror 122. The lens or lens group may be used to guide the light beam passing through the aperture 153 to the first semi-transparent mirror 122.

[0109] In some examples, the fundus 21 (i.e., the retina) of the examined eye 2 is conjugate with the aperture 153 (i.e., object-image relationship). That is, the examined eye 2 can observe the aperture 153 and the image on the aperture 153.

[0110] Figure 11 This is a schematic diagram showing the module frame of the peripheral device 17 of the fundus camera 1 according to this disclosure. In this embodiment, the fundus camera 1 may include the peripheral device 17 connected to the imaging device 14. Figure 11 As shown, the peripheral device 17 may include an information processing module 171 and a control module 172.

[0111] In some examples, the information processing module 171 can be used to process imaging information (e.g., fundus images) captured by the imaging device 14. For example, the information processing module 171 can store, transform, transmit, analyze, and display the imaging information (e.g., fundus images).

[0112] In some examples, the signal processing module 171 can receive the electrical signals converted by the imaging device 14 and use artificial intelligence algorithms to perform image compensation processing. In some examples, the signal processing module 171 can use artificial neural network technology for deep learning to automatically screen fundus images and determine lesions.

[0113] In other examples, the information processing module 171 can filter out fundus images that are difficult for artificial intelligence algorithms to distinguish and extract the fundus images, enabling medical staff to review the fundus images to improve the accuracy of diagnostic results.

[0114] In some examples, the information processing section 171 may also include a display. The display can be used to show fundus images. Additionally, related operations (e.g., magnifying fundus images) can be performed on the fundus image pairs via the display.

[0115] In some examples, the information processing module 171 can communicate with external systems or the cloud via wireless or wired connections.

[0116] In this embodiment, the control module 172 can be used to control the movement of optical elements within the first optical assembly 12 and the second optical assembly 13. For example, the control module 172 can control the distance between the focusing group 132 and the second polarizer 131 in the focusing module to achieve focusing. In this case, the imaging device 14 can clearly capture the fundus image.

[0117] In some examples, the control module 172 can control the switching of the lighting device 11, the first optical component 12, the second optical component 13, and the imaging device 14.

[0118] In some examples, the control module 172 can control the brightness of the light source 111 of the lighting device 11. When there are multiple light sources in the lighting device 11, the control module 172 can control the on / off state of each light source individually.

[0119] In some examples, the multiple guide lights 151 in the positioning device 15 may have independent on / off switches. The control module 172 can independently control the on / off switches, thereby controlling the number of illuminated guide lights 151 in the positioning device 15.

[0120] In some examples, the positioning device 15 can drive the adjustment motor of the imaging device 14 or the photoelectric sensor.

[0121] In this disclosure, the light beam provided by the illumination source in the illumination device 11 passes through the first polarizer 121 to form first polarized light with a first polarization state. The first polarized light enters the examined eye 2 and is reflected by the fundus 21 to generate reflected light. The polarization state of the reflected light changes (e.g., the reflected light has no polarization state). The reflected light passes through the second polarizer 131 to form second polarized light with a second polarization state. The second polarized light reaches the imaging device 14 to form a fundus image. The imaging device 14 is connected to the peripheral device 17. In the peripheral device 17, the control module 172 can control the distance between the focusing group 132 in the focusing module and the second polarizer 131 to achieve focusing. In this case, the imaging device 14 can obtain a relatively clear fundus image. At the same time, the information processing module 171 can store, transform, transmit, and display the imaging information captured by the imaging.

[0122] While the present invention has been specifically described above in conjunction with the accompanying drawings and embodiments, it is to be understood that the above description does not limit the invention in any way. Those skilled in the art can make modifications and variations to the present invention as needed without departing from its essential spirit and scope, and all such modifications and variations fall within the scope of the present invention.

Claims

1. An optical system for a fundus camera with an aperture stop, characterized in that: It includes a lighting device, a first optical component, a second optical component, an imaging device, and a positioning device; The lighting device includes a lighting source; The first optical component includes a first semi-transparent mirror, a first polarizer, a second semi-transparent mirror, and a retinal objective. The first polarizer is used to convert the light beam received by the first semi-transparent mirror from the illumination source into first polarized light with a first polarization state. The second semi-transparent mirror is used to reflect the first polarized light to the retinal objective. The retinal objective is used to guide the received first polarized light to the fundus of the examined eye and receive the reflected light from the fundus. The second semi-transparent mirror is used to receive the reflected light passing through the retinal objective and guide it to the second optical component. The second optical component includes a second polarizer and a focusing module. The reflected light is converted into second polarized light with a second polarization state by the second polarizer, and the focusing module guides the second polarized light to the imaging device. The imaging device is used to receive the second polarized light to form a fundus image; The positioning device includes a guiding light source and an aperture for giving the beam of the guiding light source a preset shape. The guiding light source is used to guide the line of sight of the eye being examined. The beam of the guiding light source passes through the aperture and reaches the first semi-transparent mirror. After passing through the aperture, the beam of the guiding light source is formed with the preset shape. The imaging device acquires fundus images of different regions of the eye being examined based on the guiding light source. The first optical component guides the beam of the guiding light source to the fundus of the eye being examined for imaging.

2. The fundus camera optical system as described in claim 1, characterized in that, The lighting source is a ring light source.

3. The fundus camera optical system as described in claim 1, characterized in that, The lighting device includes a light homogenizer that homogenizes the light beam from the lighting source.

4. The fundus camera optical system as described in claim 3, characterized in that, The light-diffusing plate has a conjugate relationship with the pupil of the examined eye.

5. The fundus camera optical system as described in claim 1, characterized in that, The positioning device includes a lens located between the guide light source and the aperture, wherein the light beam from the guide light source forms parallel light after passing through the lens.

6. The fundus camera optical system as described in claim 5, characterized in that, The guiding light source is positioned at the focal point of the lens.

7. The fundus camera optical system as described in claim 1, characterized in that, The polarization direction of the first polarization state is orthogonal to the polarization direction of the second polarization state.

8. The fundus camera optical system as described in claim 1, characterized in that, The aperture has a hole in the preset shape.

9. The fundus camera optical system as described in claim 1, characterized in that, The fundus of the examined eye is conjugate with the aperture.

10. A fundus camera, characterized in that: include: The fundus camera optical system as described in any one of claims 1 to 9; as well as Peripheral device, which is connected to the imaging device, The peripheral device further includes: A control module, used to control the movement of optical elements within the first and second optical assemblies; and An information processing module is used to process the imaging information captured by the imaging device.

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