Fixation target light path system for fundus camera

Abstract

The utility model discloses a kind of eye fundus camera fixation mark light path systems, it is related to eye fundus optical camera field, wherein, eye fundus camera fixation mark light path system includes: multiplexing mirror group, including multiplexing lens assembly and main mirror barrel, multiplexing lens assembly is located in main mirror barrel;Fixation module, including fixation light source and first fixation mirror barrel, first fixation mirror barrel is connected with main mirror barrel, fixation light source is located in one end of first fixation mirror barrel, fixation light source is used to form fixation mark pattern and emit fixation mark light ray;Fixation lens assembly, it is located in first fixation mirror barrel and located in the end away from fixation light source, one end of fixation lens assembly also extends to main mirror barrel inside;And reflector, it is located in mirror barrel and is obliquely arranged, fixation mark light ray is transmitted through fixation lens assembly, and it is reflected to multiplexing mirror group by reflector, fixation mark light ray is transmitted through multiplexing mirror group and is shot into human eye.The eye fundus camera fixation mark light path system provided in the utility model technical scheme can take into account the needs of various population.

Description

Technical Field

[0001] This utility model relates to the field of fundus optical camera technology, and in particular to a fundus camera fixed target optical path system. Background Technology

[0002] During certain ophthalmological examinations, the test subject is asked to fixate on a fixation target pattern in a fixation optical device. Given that most current fundus camera fixation target optical path systems use a single-wavelength fixation target design, related technologies typically employ a continuously lit or flashing monochromatic point light source as the fixation target. However, this may not be suitable for colorblind individuals and cannot meet the needs of various population groups. Utility Model Content

[0003] The main purpose of this invention is to provide a fixed optical path system for fundus cameras, which aims to solve the technical problem that current fundus cameras cannot meet the needs of various groups of people.

[0004] To achieve the above objectives, this utility model proposes a fundus camera fixation target optical path system, comprising: A multiplex lens assembly includes a multiplex lens assembly and a main lens barrel, wherein the multiplex lens assembly is disposed in the main lens barrel; A fixation module includes a fixation light source and a first fixation lens barrel. The first fixation lens barrel is connected to the main lens barrel. The fixation light source is located at one end of the first fixation lens barrel. The fixation light source is used to form a fixation target pattern and emit fixation target light. A fixation lens assembly, disposed within the first fixation lens barrel and located at one end opposite to the fixation light source, wherein one end of the fixation lens assembly also extends into the main lens barrel; and A reflector is disposed inside the lens barrel and is tilted. The fixed target light passes through the fixed lens assembly and is reflected by the reflector to the multiplex lens group. The fixed target light passes through the multiplex lens group and enters the human eye.

[0005] The fixation lens assembly includes a second fixation lens barrel and a first fixation positive lens, a second fixation positive lens, and a fixation negative lens disposed inside the second fixation lens barrel. The first fixation positive lens is disposed near the reflector, the fixation negative lens is disposed near the fixation module, the second fixation positive lens is disposed between the first fixation positive lens and the fixation negative lens, and one end of the second fixation lens barrel is disposed inside the first fixation lens barrel, and the other end extends into the main lens barrel.

[0006] In one embodiment, the second fixation lens barrel is provided with a mounting ring inside, the second fixation positive lens and the fixation negative lens are respectively disposed on both sides of the mounting ring, the side of the fixation negative lens away from the mounting ring is provided with a first fixation pressure ring, and the first fixation pressure ring abuts against the fixation negative lens, a fixation spacer is provided between the second fixation positive lens and the first fixation positive lens, and a second fixation pressure ring is provided on the side of the first fixation positive lens away from the second fixation positive lens.

[0007] In one embodiment, the multiplexed lens assembly includes an eyepiece module and a relay lens module. The eyepiece module is located at the end of the main lens barrel away from the reflector, and the relay lens module is located inside the main lens barrel. The reflector reflects the fixed target light rays through the relay lens module and the eyepiece module in sequence.

[0008] In one embodiment, the eyepiece module includes an eyepiece tube and a first eyepiece and a second eyepiece disposed within the eyepiece tube. The eyepiece tube is slidably connected to the main tube, and one end of the eyepiece tube extends out of the main tube. An eyepiece spacer is provided between the first eyepiece and the second eyepiece, and an eyepiece retainer is provided on the side of the second eyepiece facing away from the first eyepiece. The fixed target light passes through the second eyepiece and the first eyepiece in sequence.

[0009] In one embodiment, the relay lens module includes a first relay lens and a second relay lens, with a relay spacer between them, and the fixed target light beam passes through the second relay lens and the first relay lens in sequence.

[0010] In one embodiment, the fixed-view module further includes a protective glass and a filter, the protective glass being disposed between the fixed-view light source and the filter.

[0011] In one embodiment, the fixed-view light source includes a plurality of light-emitting points; or, the fixed-view light source includes a plurality of light-emitting pixels.

[0012] In one embodiment, the fundus camera fixation target optical path system further includes a base, the base including a connecting part and a supporting part disposed on the connecting part, the connecting part being connected to the main lens barrel, the supporting part extending into the main lens barrel, the supporting part being provided with a supporting inclined surface, and the reflector being disposed on the supporting inclined surface.

[0013] In one embodiment, the connecting portion is provided with a first through hole and a second through hole, the first through hole and the second through hole being located on opposite sides of the reflector, respectively.

[0014] This invention employs a multiplexed lens assembly, where a reflector reflects the fixation light to the multiplexed lens assembly, thus adding a fixation module and enabling the fixation function of a fundus camera. The multiplexed lens assembly is also used in other optical paths, significantly reducing the number of optical lenses and saving layout space. A fixation lens assembly is placed between the fixation module and the multiplexed lens assembly. This assembly refracts the light emitted from the fixation light source to form a clear fixation target pattern, thereby achieving an achromatic effect to meet the needs of various user groups. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 A schematic diagram of the optical path of the fundus camera fixation target optical path system provided by this utility model; Figure 2 A cross-sectional structural schematic diagram of an embodiment of the fundus camera fixation target optical path system provided by this utility model; Figure 3 A cross-sectional schematic diagram of the fixation module and fixation lens assembly in an embodiment of the fundus camera fixation target optical path system provided by this utility model; Figure 4 A schematic diagram of the structure of an embodiment of the fundus camera fixation target optical path system provided by this utility model; Figure 5 A schematic diagram of an embodiment of the fundus camera fixation target optical path system provided by this utility model; Figure 6 MTF curve of an embodiment of the fundus camera fixation target optical path system provided by this utility model.

[0017] Explanation of icon numbers: 100. Main lens barrel; 110. Eyepiece module; 111. Eyepiece barrel; 112. First eyepiece; 113. Second eyepiece; 114. Eyepiece spacer; 115. Eyepiece retaining ring; 120. Relay lens module; 121. First relay lens; 122. Second relay lens; 123. Relay spacer; 200. Fixation module; 210. Fixation light source; 220. First fixation lens barrel; 230. Protective glass; 240. Filter; 300. Fixation lens assembly; 310. Second fixation lens barrel; 320. First fixation positive lens; 330. Second fixation positive lens; 340. Fixation negative lens; 350. Mounting ring; 360. First fixation retaining ring; 370. Fixation spacer; 380. Second fixation retaining ring; 400. Reflector; 500, base; 510, connecting part; 520, bearing part; 530, first through hole; 540, second through hole.

[0018] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0020] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0021] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0022] In the existing technology, most fundus camera fixation target optical path systems adopt a single-wavelength fixation target design. In related technologies, a continuously lit or flashing monochromatic point light source is usually used as the fixation target, but this may not be suitable for colorblind people and cannot meet the needs of various groups.

[0023] This invention proposes a fixed-beam optical path system for a fundus camera.

[0024] Please see Figures 1 to 4 In one embodiment of this utility model, the fundus camera fixation target optical path system includes: a multiplexer assembly, a fixation module 200, a fixation lens assembly 300, and a reflector 400. The multiplexer assembly includes a multiplexer lens assembly and a main lens barrel 100, with the multiplexer lens assembly disposed in the main lens barrel 100. The fixation module 200 includes a fixation light source 210 and a first fixation lens barrel 220, with the first fixation lens barrel 220 connected to the main lens barrel 100. The fixation light source 210 is disposed in the first fixation lens barrel 220. At one end of 20, the fixation light source 210 is used to form a fixation target pattern and emit fixation target light; the fixation lens assembly 300 is disposed inside the first fixation lens barrel 220 and located at the end opposite to the fixation light source 210, and one end of the fixation lens assembly 300 also extends into the main lens barrel 100; the reflector 400 is disposed inside the lens barrel and is tilted, the fixation target light passes through the fixation lens assembly 300 and is reflected by the reflector 400 to the multiplex lens group, and the fixation target light enters the human eye after passing through the multiplex lens group.

[0025] It should be noted that the fixation lens assembly 300 is a lens group with a precise achromatic design. For example, it can be an achromatic doublet lens made by cementing a crown glass positive lens and a flint glass negative lens together, or it can be a more complex apochromatic lens group containing aspherical lenses, to ensure that the fundus images acquired by the main imaging optical path have high resolution and true color reproduction capabilities.

[0026] In practical implementation, the fixation module 200 is connected to the main lens barrel 100 of the multiplex lens group through its first fixation lens barrel 220, forming a stable whole. The fixation module 200 includes a fixation light source 210, which can be a monochrome LED or an OLED micro-display that can display specific patterns (such as cross-shaped or dot-shaped patterns). Specifically, the fixation light source 210 is installed at one end of the first fixation lens barrel 220, and the axis of the first fixation lens barrel 220 has a certain angle with the axis of the main lens barrel 100. The reflector 400 is tilted and reflects the fixation light path to be consistent with the axis direction of the main lens barrel 100, and then shines into the human eye.

[0027] The multiplex lens assembly can be constructed using simple single or multiple spherical lenses. Its main function is to refract the fixed target light emitted from the fixed light source 210 after it has passed through the fixed lens assembly 300 (which has been achromatic), and to direct the fixed target light into the eye. The reflecting mirror 400 is tilted inside the main lens barrel 100, and its position is precisely calculated so that the light from the fixed light source 210, after passing through the fixed lens assembly 300, is reflected and redirected, and accurately enters the multiplex lens assembly.

[0028] This invention employs a multiplexed lens assembly, with the reflector 400 reflecting the fixation light back to the multiplexed lens assembly, thereby adding a fixation module 200 to achieve the fixation function of a fundus camera. The multiplexed lens assembly is also used in other optical paths, significantly reducing the number of optical lenses and saving layout space. A fixation lens assembly 300 is placed between the fixation module 200 and the multiplexed lens assembly. The fixation lens assembly 300 refracts the light emitted from the fixation light source 210 to form a clear fixation target pattern, thus achieving an achromatic effect to meet the needs of various user groups.

[0029] In one embodiment, the fixed lens assembly 300 includes a second fixed lens barrel 310 and a first fixed positive lens 320, a second fixed positive lens 330, and a fixed negative lens 340 disposed inside the second fixed lens barrel 310. The first fixed positive lens 320 is disposed near the reflector 400, the fixed negative lens 340 is disposed near the fixed module 200, and the second fixed positive lens 330 is disposed between the first fixed positive lens 320 and the fixed negative lens 340. One end of the second fixed lens barrel 310 is disposed inside the first fixed lens barrel 220, and the other end extends into the main lens barrel 100.

[0030] It should be noted that the fixed-focus negative lens 340 is typically made of high-dispersion (low Abbe number) flint glass. Its function is to generate dispersion in the opposite direction to that of the positive lens, thereby canceling the chromatic aberration introduced by the positive lens, and is key to chromatic aberration correction. In specific implementation, when the white light emitted by the fixed-focus light source 210, such as a white LED, first passes through the fixed-focus negative lens 340, it diverges, with blue light having a larger divergence angle than red light. Subsequently, the light passes through the second fixed-focus positive lens 330 and the first fixed-focus positive lens 320, which converge the light. Through precise optical design, calculating the curvature, spacing, and glass material of these three lenses, light of different wavelengths (such as blue and red) can be converged to the same focal point after passing through this component, or its dispersion can be greatly compensated.

[0031] The achromatic design of the fixation lens assembly 300 first actively controls the chromatic aberration of the fixation light to an extremely low level within the fixation target optical path. Then, the fixation target light enters the multiplex lens assembly, which performs final and precise aberration correction on this basis, and projects a clear fixation target image onto the human eye's retina. This fundamentally avoids chromatic aberration problems such as color fringing, improves the patient's fixation experience, and enhances the overall imaging reliability of the system.

[0032] In this embodiment, the axis of the first fixation lens barrel 220 is collinear with the axis of the second fixation lens barrel 310. The second fixation lens barrel 310 is fixed inside the first fixation lens barrel 220 by a set screw or directly screwed into the first fixation lens barrel 220. Of course, the second fixation lens barrel 310 can also be slidably disposed inside the first fixation lens barrel 220. The position of the second fixation lens barrel 310 inside the first fixation lens barrel 220 can be adjusted, such as by slotting the side wall of the first fixation lens barrel 220 and connecting the second fixation lens barrel 310 through an external structure (adjusting rod, etc.).

[0033] In one embodiment, a mounting ring 350 is provided inside the second fixation lens barrel 310. The second fixation positive lens 330 and the fixation negative lens 340 are respectively disposed on both sides of the mounting ring 350. A first fixation retaining ring 360 is provided on the side of the fixation negative lens 340 away from the mounting ring 350, and the first fixation retaining ring 360 abuts against the fixation negative lens 340. A fixation spacer 370 is provided between the second fixation positive lens 330 and the first fixation positive lens 320. A second fixation retaining ring 380 is provided on the side of the first fixation positive lens 320 away from the second fixation positive lens 330.

[0034] The mounting ring 350 is an annular protrusion machined directly inside the second fixation lens barrel 310 and is an integral part of the second fixation lens barrel 310. It provides a precise and uniform axial mounting reference for the core lens assembly. The second fixation positive lens 330 and the fixation negative lens 340 abut against both sides of the mounting ring 350, ensuring that the axial distance (air gap) between these two key lenses, which need to fit closely together and coordinately correct aberrations in the achromatic design, is determined and controlled with high precision. This air gap is a critical variable in optical design; even micron-level errors can significantly affect the achromatic effect.

[0035] The first fixation ring 360 is located outside the fixation negative lens 340 and is used to precisely set the distance between the lens and adjacent components (such as the end face of the lens barrel or the fixation light source 210). The fixation spacer 370 is located between the second fixation positive lens 330 and the first fixation positive lens 320, and is one of the most critical air gaps for achieving achromaticity. The second fixation ring 380 is located outside the first fixation positive lens 320 to maintain a safe distance between it and the reflector 400 or other structures.

[0036] In one embodiment, the multiplexed lens assembly includes an eyepiece module 110 and a relay lens module 120. The eyepiece module 110 is located at the end of the main lens barrel 100 away from the reflecting mirror 400, and the relay lens module 120 is located inside the main lens barrel 100. The fixed target light reflected by the reflecting mirror 400 passes sequentially through the relay lens module 120 and the eyepiece module 110. The eyepiece module 110 is positioned close to the human eye, and the relay lens module 120 is positioned close to the reflecting mirror 400, which allows for the decomposition and optimization of the overall aberration correction task. In specific implementation, the eyepiece module 110 further includes an eyepiece tube 111 and a first eyepiece 112 and a second eyepiece 113 disposed within the eyepiece tube 111. The eyepiece tube 111 is slidably connected to the main tube 100, and one end of the eyepiece tube 111 extends out of the main tube 100. An eyepiece spacer 114 is provided between the first eyepiece 112 and the second eyepiece 113, and an eyepiece retaining ring 115 is provided on the side of the second eyepiece 113 facing away from the first eyepiece 112. The target light passes through the second eyepiece 113 and the first eyepiece 112 in sequence. The relay lens module 120 includes a first relay lens 121 and a second relay lens 122, and a relay spacer 123 is provided between them. The target light passes through the second relay lens 122 and the first relay lens 121 in sequence.

[0037] The sliding connection between the eyepiece tube 111 and the main lens tube 100 is primarily used for refractive power adjustment to compensate for differences in vision between the patient and the doctor. From an achromatic perspective, the first eyepiece 112 and the second eyepiece 113 are moved as a single sub-unit, ensuring stable achromatic performance throughout the entire range of motion. In practical implementation, the eyepiece tube 111 can be connected to a motor drive mechanism to precisely control the distance between the eyepiece module 110 and the relay lens module 120, thereby achieving refractive power adjustment.

[0038] The first eyepiece 112, the second eyepiece 113, the first relay lens 121, and the second relay lens 122 are either convex or concave lenses, depending on the actual light design requirements. No limitation is made here, as long as the light refraction requirements are met. In this embodiment, the fixed target light passes sequentially through the second relay lens 122, the first relay lens 121, the second eyepiece 113, and the first eyepiece 112, achieving optimized aberration balance and ensuring that the fixed target projected onto the retina is clear and free of chromatic aberration at all refractive adjustment positions.

[0039] In one embodiment, the fixed-view module 200 further includes a protective glass 230 and a filter 240, with the protective glass 230 disposed between the fixed-view light source 210 and the filter 240.

[0040] The filter 240 selectively allows light of specific wavelengths to pass through while blocking other wavelengths. The filter 240 is pluggable and switchable; it can be inserted when only a single-color fixation target is needed and removed when not, and different filters 240 can be selected to match different fixation light sources 210. Understandably, the fixation lens barrel has a pluggable slot, and the filter 240 is inserted into the fixation lens barrel through this slot. By using the filter 240, the broadband white light emitted by the fixation light source 210 (such as a white LED) can be filtered into a quasi-monochromatic light with a very narrow wavelength range. When the light entering the subsequent complex lens group (fixation lens assembly 300, relay lens module 120, eyepiece module 110) is almost of a single wavelength, the dispersion phenomenon itself is physically eliminated to a large extent, greatly reducing the achromatic design pressure of all subsequent lens groups, making it easier to achieve extremely high image sharpness, and even approaching the ideal state of zero chromatic aberration.

[0041] The protective glass 230 primarily serves a physical protection function, preventing dust, moisture, or accidental contact during operation from damaging the expensive fixed-state light source 210 (such as an OLED microdisplay) and the precision filter 240. The protective glass 230 maintains the optical cleanliness of the light source, ensuring that the pure quasi-monochromatic light generated by the filter 240 can enter the optical system without interference, thereby guaranteeing the signal-to-noise ratio and purity of the final output image from the entire achromatic optical chain.

[0042] In one embodiment, the fixed-view light source 210 includes a plurality of light-emitting points; or, the fixed-view light source 210 includes a plurality of light-emitting pixels.

[0043] The fixation light source 210 can be a point light source or a single pixel of the light-emitting screen to emit light as the light source for the fixation target optical path. The position and number of the emitting pixels are controlled to form different emitting patterns, which serve as the object plane for the entire fixation optical path. After passing through the entire fixation target optical path, the image is finally projected onto the human retina, guiding the eye's gaze to be fixed in different positions for fundus imaging. Simultaneously, by switching different fixation target positions, the eye is guided to rotate, thus imaging different areas of the fundus. Finally, by stitching the images together, a complete fundus image is obtained, which is beneficial for ophthalmologists to gain a comprehensive understanding of the patient's fundus. The fixation target optical path adopts a reverse optical path design. Parallel light incident on the eyepiece module 110 is finally imaged on the LCD screen, and the dot plot and MTF curve are shown below. Figure 5 and Figure 6 As shown.

[0044] In this embodiment, the air gap between the first eyepiece 112 and the second eyepiece 113 is 0.2 mm, and the air gap between the second eyepiece 113 and the first relay lens 121 is 120 mm. This air gap is for shooting a human eye with zero diopter. When the eyepiece module 110 focuses for a human eye with different diopter, the air gap will change. Within the diopter focusing range of -18D to +18D, the air gap changes from 113 to 127 mm. The air gap between the first relay lens 121 and the second relay lens 122 is 3mm; the air gap between the first and second relay lenses 122 and the center of the reflector 400 is 4.5mm; the air gap between the center of the reflector 400 and the fixed lens D-1 is 20mm; the air gap between the first fixed positive lens 320 and the second fixed positive lens 330 is 0.5mm; the air gap between the second fixed positive lens 330 and the fixed negative lens 340 is 2.17mm; and the air gap between the fixed negative lens 340 and the fixed module 200 is 17.12mm. In this embodiment, the light sequentially enters the fixed lens assembly 300, the reflector 400, the relay lens module 120, and the eyepiece module 110 after being emitted by the fixed light source 210, and finally enters the human eye for imaging. This invention addresses the issues of limited color richness in monochrome images caused by the monochromatic fixation light source 210 in current fundus cameras and its unfriendliness to colorblind individuals. It incorporates an achromatic design that balances the imaging performance of the fixation light path across different wavelengths, and allows for switching between different wavelengths via a pluggable filter 240. Furthermore, since the fixation light path and the imaging light path can simultaneously adjust diopter, the fixation light path can synchronously adjust to achieve clarity during different eye diopter adjustments.

[0045] In one embodiment, the fundus camera fixation target optical path system further includes a base 500, which includes a connecting part 510 and a support part 520 disposed on the connecting part 510. The connecting part 510 is connected to the main lens barrel 100, and the support part extends into the main lens barrel 100. The support part 520 is provided with a support slope, and the reflector 400 is disposed on the support slope.

[0046] The bearing slope is a precision-machined optical reference surface with a specific angle, and the angle of the bearing slope directly determines the tilt angle of the reflector 400. The angle of the reflector 400 is the core pivot of the optical path reversal; even a slight deviation can cause the entire fixed target optical path to deviate significantly from the design path. The base 500 is installed at one end of the lens barrel away from the eyepiece module 110, and the base 500 is firmly connected to the main lens barrel 100 through its connecting part 510 to maintain the stability of the optical path.

[0047] In one embodiment, the connecting portion 510 is provided with a first through hole 530 and a second through hole 540, the first through hole and the second through hole being located on opposite sides of the reflector.

[0048] The fundus camera also has an inherent illumination and imaging optical path. The illumination optical path is used to illuminate the fundus, and the imaging optical path is used for fundus imaging. Both are inherent optical paths of the fundus camera, and their specific components will not be described in detail in this embodiment. In specific implementation, the illumination, imaging, and fixation target optical paths share a multiplexer assembly. The other components of the illumination and imaging optical paths are located on the side of the base away from the main lens barrel. To avoid affecting the illumination and imaging optical paths of the fundus camera, the reflector 400 reflects the fixation target optical path after the relay lens module 120 upwards. The illumination and imaging optical paths pass through the first and second through holes of the base 500 of the reflector 400, respectively, thus not affecting the optical paths of other functions.

[0049] The above description is merely an exemplary embodiment of the present utility model and does not limit the scope of protection of the present utility model. Any equivalent structural transformations made based on the inventive concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the scope of protection of the present utility model.

Claims

1. A fixation target optical path system for a fundus camera, characterized in that, include: A multiplex lens assembly includes a multiplex lens assembly and a main lens barrel, wherein the multiplex lens assembly is disposed in the main lens barrel; A fixation module includes a fixation light source and a first fixation lens barrel. The first fixation lens barrel is connected to the main lens barrel. The fixation light source is located at one end of the first fixation lens barrel. The fixation light source is used to form a fixation target pattern and emit fixation target light. A fixation lens assembly, disposed within the first fixation lens barrel and located at one end opposite to the fixation light source, wherein one end of the fixation lens assembly also extends into the main lens barrel; and A reflector is disposed inside the lens barrel and is tilted. The fixed target light passes through the fixed lens assembly and is reflected by the reflector to the multiplex lens group. The fixed target light passes through the multiplex lens group and enters the human eye.

2. The fundus camera fixation target optical path system as described in claim 1, characterized in that, The fixation lens assembly includes a second fixation lens barrel and a first fixation positive lens, a second fixation positive lens, and a fixation negative lens disposed inside the second fixation lens barrel. The first fixation positive lens is disposed near the reflector, the fixation negative lens is disposed near the fixation module, the second fixation positive lens is disposed between the first fixation positive lens and the fixation negative lens, and one end of the second fixation lens barrel is disposed inside the first fixation lens barrel, and the other end extends into the main lens barrel.

3. The fundus camera fixation target optical path system as described in claim 2, characterized in that, The second fixation lens barrel has a mounting ring inside. The second fixation positive lens and the fixation negative lens are respectively located on both sides of the mounting ring. The side of the fixation negative lens away from the mounting ring has a first fixation pressure ring, and the first fixation pressure ring abuts against the fixation negative lens. A fixation spacer is provided between the second fixation positive lens and the first fixation positive lens. The side of the first fixation positive lens away from the second fixation positive lens has a second fixation pressure ring.

4. The fundus camera fixation target optical path system as described in claim 1, characterized in that, The multiplexed lens assembly includes an eyepiece module and a relay lens module. The eyepiece module is located at the end of the main lens barrel away from the reflector, and the relay lens module is located inside the main lens barrel. The reflector reflects the fixed target light rays through the relay lens module and the eyepiece module in sequence.

5. The fundus camera fixation target optical path system as described in claim 4, characterized in that, The eyepiece module includes an eyepiece tube and a first eyepiece and a second eyepiece disposed within the eyepiece tube. The eyepiece tube is slidably connected to the main tube, and one end of the eyepiece tube extends out of the main tube. An eyepiece spacer is provided between the first eyepiece and the second eyepiece, and an eyepiece retainer is provided on the side of the second eyepiece away from the first eyepiece. The fixed target light passes through the second eyepiece and the first eyepiece in sequence.

6. The fundus camera fixation target optical path system as described in claim 4, characterized in that, The relay lens module includes a first relay lens and a second relay lens, with a relay spacer between them. The fixed target light beam passes through the second relay lens and the first relay lens in sequence.

7. The fundus camera fixation target optical path system as described in claim 1, characterized in that, The fixed-view module also includes a protective glass and a filter, with the protective glass disposed between the fixed-view light source and the filter.

8. The fundus camera fixation target optical path system as described in claim 1, characterized in that, The fixed-view light source includes a plurality of light-emitting points; or, the fixed-view light source includes a plurality of light-emitting pixels.

9. The fundus camera fixation target optical path system as described in claim 1, characterized in that, The fundus camera fixation target optical path system also includes a base, the base including a connecting part and a supporting part disposed on the connecting part, the connecting part being connected to the main lens barrel, the supporting part extending into the main lens barrel, the supporting part being provided with a supporting inclined surface, and the reflecting mirror being disposed on the supporting inclined surface.

10. The fundus camera fixation target optical path system as described in claim 9, characterized in that, The connecting part is provided with a first through hole and a second through hole, which are located on opposite sides of the reflector.

Images