Lens module and fundus camera having the same

Abstract

The present invention provides a lens module for converging imaging light reflected from the fundus, comprising: a first lens group, an illumination module and a second lens group arranged in sequence from the fundus side to the imaging side; wherein the illumination module comprises a plurality of light-emitting elements and a light shielding member; the plurality of light-emitting elements are cocircular and evenly distributed on the circumference; the light shielding member is cylindrical or truncated cone-shaped, and is provided with a light-through groove penetrating the light shielding member; the light-emitting element cooperates with the light shielding member so that the illumination range of the light-emitting element is annular. Compared with the prior art, the illumination system of the lens module of the present invention has a simple structure, can achieve uniform illumination, and can effectively reduce the influence of reflected light on the imaging system.

Description

Technical Field

[0001] The invention relates to a lens module and a fundus camera having the lens module. Background Art

[0002] Fundus cameras belong to the field of medical imaging and are used to obtain images of the human retina so that medical personnel can examine fundus diseases or assist medical personnel in judging the condition of other organs. Since the blood vessels in the fundus are the only blood vessels in the human body that can be directly observed through the body surface, medical personnel can use fundus cameras to check whether there are lesions in the optic nerve, retina, choroid and refractive media in the fundus. Fundus cameras can also be used to assist in the diagnosis and condition judgment of other systemic diseases, such as screening retinal photos to detect cerebral infarction, cerebral hemorrhage, cerebral arteriosclerosis, brain tumors, diabetes, kidney disease, hypertension, retinopathy of prematurity, glaucoma, age-related macular degeneration, etc. The earlier these diseases are detected, the more conducive to clinical treatment. Therefore, fundus cameras are widely used in clinical screening of fundus diseases and have become an indispensable medical device.

[0003] However, in order to simplify the lighting system, the lens module of the existing handheld fundus camera usually uses an off-axis lighting system, that is, the lighting lamp deviates from the optical axis and illuminates the objective lens obliquely. This makes the lighting of the objective lens extremely uneven, thereby affecting the image quality. In addition, the reflected light formed by the illumination light emitted by the lighting lamp after being reflected by the surface of the objective lens will also seriously interfere with the imaging, thereby reducing the image quality.

[0004] In view of the above problems, it is necessary to provide a new lens module to solve the above problems. Summary of the invention

[0005] In view of the deficiencies in the prior art, the technical problem solved by the present invention is to provide a lens module and a fundus camera having the lens module. The lighting system of the lens module has a simple structure, can achieve uniform lighting, and can effectively reduce the impact of reflected light on the imaging system.

[0006] To solve the above technical problems, the technical solution of the present invention is achieved as follows:

[0007] A lens module is used to converge imaging light reflected from the fundus, comprising: a first lens group, an illumination module and a second lens group arranged in sequence from the fundus side to the imaging side; wherein the illumination module comprises a plurality of light-emitting elements and a light-shielding member; the plurality of light-emitting elements are cocircular and evenly distributed on the circumference; the light-shielding member is cylindrical or truncated cone-shaped, and is provided with a light-through groove penetrating the light-shielding member; the light-emitting element cooperates with the light-shielding element so that the illumination light emitted by the light-emitting element is projected toward the cornea in a ring-shaped form.

[0008] Furthermore, the first lens group includes a first lens close to the lighting module, and the first lens has a first surface close to the lighting module; the light-through groove includes an incident port close to the first lens group and an exit port away from the first lens group; the light-emitting element and the light-shielding member are configured so that the illumination area of ​​the reflected light formed by the illumination light emitted by the light-emitting element after being reflected by the first surface does not overlap with the exit port.

[0009] Furthermore, the first lens group includes a first lens near the lighting module, and the first lens has a first surface near the lighting module; the light-through groove includes an incident port near the first lens group and an exit port away from the first lens group; the light-emitting element and the light-shielding member are configured so that the illumination area of ​​the reflected light formed by the illumination light emitted by the light-emitting element after being reflected by the first surface partially overlaps with the exit port, and the area of ​​the overlapping portion is less than half of the area of ​​the exit port.

[0010] Furthermore, the first surface is a convex surface or a concave surface.

[0011] Furthermore, the lighting module also includes an aperture, and the aperture cooperates with the shading member to form an annular groove so that the lighting light emitted by the light-emitting element can pass through.

[0012] Furthermore, the projections of the annular groove and the light-emitting element on the plane where the first lens is located overlap.

[0013] Furthermore, the second lens group has a second lens close to the first lens; a line connecting the edges of the first lens and the second lens on the same side is defined as a boundary line; the light-through groove is in a truncated cone shape, an angle between its generatrix and the optical axis is not less than an angle between the boundary line and the optical axis, and the boundary line is located between the generatrix and the optical axis.

[0014] Furthermore, the light emitting elements include four first light emitting elements and four second light emitting elements, and the first light emitting elements and the second light emitting elements are arranged at intervals.

[0015] Furthermore, the first light-emitting element emits visible light, and the second light-emitting element emits invisible light.

[0016] A fundus camera comprises the above-mentioned lens module.

[0017] The beneficial effects of the present invention are as follows: compared with the prior art, the lighting system of the lens module of the present invention has a simple structure, can achieve uniform lighting, and can effectively reduce the influence of reflected light on the imaging system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1Shown is a schematic structural diagram of the lens module of the present invention.

[0019] Figure 2 for Figure 1 The illumination light path diagram of the illumination module of the lens module is shown.

[0020] Figure 3 for Figure 1 The first reflected light path diagram of the illumination module of the lens module is shown.

[0021] Figure 4 for Figure 1 The second reflection light path diagram of the illumination module of the lens module is shown.

[0022] Figure 5 for Figure 1 The third reflected light path diagram of the illumination module of the lens module is shown.

[0023] Figure 6 Shown is a schematic diagram of the distribution of light-emitting elements.

[0024] Figure 7 Another distribution diagram of light-emitting elements is shown.

[0025] Figure 8 A schematic cross-sectional view of a light shielding member is shown. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical scheme and advantages of the present invention clearer, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Examples of these preferred embodiments are illustrated in the accompanying drawings. The embodiments of the present invention shown in the accompanying drawings and described according to the accompanying drawings are merely exemplary, and the present invention is not limited to these embodiments.

[0027] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the scheme of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0028] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0029] See also Figure 1As shown, the lens module 100 of the present invention is used to converge imaging light reflected from the fundus of the observed eye 40 to form a fundus image of the observed eye 40 in the imaging module 50. The lens module 100 includes a first lens group 10, an illumination module 20, and a second lens group 30, which are arranged in sequence from the fundus side EYE to the imaging side IMG. The first lens group 10 and the second lens group 30 can be a single lens, or a lens group composed of a plurality of lenses, or a glued lens formed by a plurality of lenses, or a lens group formed by a glued lens, one or more lenses. The first lens group 10 includes a first lens 11 close to the illumination module 20, and the first lens 11 has a first surface 111 close to the illumination module 20. The second lens group 30 has a second lens 31 close to the first lens 11. The line connecting the same-side edges of the first lens 11 and the second lens 31 is defined as the boundary 60 (as shown in FIG. 6 ). Figure 1 as shown).

[0030] See also Figure 1 , Figure 6 as well as Figure 8 As shown, the lighting module 20 includes a lamp holder 21 in a circular shape, a plurality of light-emitting elements 22 mounted on the lamp holder 21, and a light shielding member 23 matched with the light-emitting elements 22. The plurality of light-emitting elements 22 are cocircular and evenly distributed on the circumference. Such arrangement enables the radiation distribution of the light-emitting elements 22 on the first lens group 10 to be relatively uniform. The light-emitting elements 22 include a first light-emitting element 221 that emits visible light and a second light-emitting element 222 that emits invisible light, and the first light-emitting elements 221 and the second light-emitting elements 222 are arranged at intervals. Preferably, the first light-emitting elements 221 and the second light-emitting elements 222 are 4 in number, and such arrangement can take into account the problem of uniform radiation distribution and spatial distribution of the light-emitting elements 22 at the same time, so that the light-emitting source 22 on the lamp holder 21 will not be crowded while the lighting module 20 achieves uniform illumination. The first light-emitting element 221 is used to capture fundus images, and the second light-emitting element 222 is used for image preview. Since the eyes cannot perceive invisible light, the pupil will not contract when the invisible light shines on the eyeball, which makes it easy for the user to observe the fundus image in the image preview mode, and obtain the best preview image by adjusting the distance and angle between the lens module 100 and the eyeball, adjusting the focal length, and then taking a picture of the fundus, thereby effectively improving the probability of taking the best fundus image. In addition, invisible light will not irritate the eyes, so it will not cause discomfort to the eyeball, thereby effectively improving the user experience. In the present embodiment, the first light-emitting element 221 and the second light-emitting element 222 are cocircular, but in other embodiments, the first light-emitting element 221 and the second light-emitting element 222 may not be cocircular. For example, please refer to Figure 7As shown, the four first light-emitting elements 221 are cocircular and evenly distributed on the circumference; the four second light-emitting elements 222 are cocircular and evenly distributed on the circumference; however, the first light-emitting element 221 and the second light-emitting element 222 are not cocircular.

[0031] See also Figure 8 as well as Figure 1 As shown, the shading member 23 is roughly cylindrical or truncated cone-shaped, and is provided with a light-through groove 231 that passes through the shading member 23 to allow the imaging light reflected from the fundus to pass through. The shading member 23 cooperates with the light-emitting element 22 so that the illumination range of the light-emitting element 22 is annular, and thus the illumination light emitted by the light-emitting element 22 is projected toward the cornea in a ring-shaped form. Since the corneal surface is convex, and the angle between its normal 80 and the optical axis 70 gradually increases from the center of the cornea to the periphery. Therefore, the reflected light generated by the illumination light emitted by the light-emitting element 22 at the periphery of the cornea will not enter the lens module 100, thereby preventing the corneal reflected light from affecting the imaging quality. Figure 2 As shown. Such a configuration can avoid the situation where reflected light is incident on the lens module 100 due to direct irradiation of the center of the cornea. The light-through groove 231 is in a truncated cone shape, and the angle between its generatrix 230 and the optical axis 70 is not less than the angle between the boundary line 60 and the optical axis 70, and the boundary line 60 is located between the generatrix 230 and the optical axis 70. Such a configuration is conducive to the light shielding member 23 to collect imaging light. The light-through groove 231 includes an incident port 232 close to the first lens group 10 and an exit port 233 away from the first lens group 10. Please refer to Figure 3 As shown in FIG. 4 , preferably, the light emitting element 22 and the light shielding member 23 are configured so that the illumination area of ​​the reflected light formed by the illumination light emitted by the light emitting element 22 after being reflected by the first surface 111 partially overlaps with the exit port 233, and the area of ​​the overlapping part is less than half of the area of ​​the exit port, that is, only a small part of the reflected light formed by the light emitting element 22 after being reflected by the first surface 111 enters the exit port 233. With such a configuration, the influence of the reflected light on the imaging quality can be effectively reduced, thereby improving the imaging quality. Referring to FIG. 4 , preferably, the light emitting element 22 and the light shielding member 23 are configured so that the illumination area of ​​the reflected light formed by the illumination light emitted by the light emitting element after being reflected by the first surface 111 does not overlap with the exit port 233, that is, the reflected light formed by the light emitting element 22 after being reflected by the first surface 111 does not enter the exit port 233. With such a configuration, the influence of the reflected light on the imaging quality can be completely avoided, thereby effectively improving the imaging quality. In this embodiment, the first surface 111 is a convex surface, but in other embodiments, the first surface 111 may also be a concave surface, such as Figure 5 See Figure 2As shown, preferably, the lighting module 20 further includes an aperture 24, and the aperture 24 cooperates with the light shielding member 23 to form an annular groove 25, so that the illumination light emitted by the light emitting element 22 can pass through. In this way, it is convenient to further adjust the illumination range of the light emitting element 22. The projections of the annular groove 25 and the light emitting element 22 on the plane where the first lens 11 is located at least partially overlap.

[0032] The present invention further provides a fundus camera, which includes the lens module 100 .

[0033] Compared with the prior art, the illumination system of the lens module 100 of the present invention has a simple structure, can achieve uniform illumination, and can effectively reduce the influence of reflected light on the imaging system.

[0034] It is particularly necessary to point out that, for those skilled in the art, equivalent changes made to the present invention under the teachings of the present invention should still be included in the scope claimed by the patent application of the present invention.

Claims

1. A lens module for converging imaging light reflected from the fundus, characterized in that: include: The first lens group, the illumination module and the second lens group are sequentially arranged from the fundus side to the imaging side; wherein the illumination module comprises a plurality of light-emitting elements and a light-shielding member; the plurality of light-emitting elements are cocircular and evenly distributed on the circumference; the light-shielding member is cylindrical or truncated cone-shaped, and is provided with a light-through groove penetrating the light-shielding member; the light-emitting element cooperates with the light-shielding element so that the illumination light emitted by the light-emitting element is projected toward the cornea in a ring-shaped form; the first lens group comprises a first lens close to the illumination module, and the first lens has a first surface close to the illumination module; the light-through groove comprises an incident port close to the first lens group and an exit port away from the first lens group; The area illuminated by the reflected light formed by the illumination light emitted by the light-emitting element after being reflected by the first surface is the illumination area, and the light-emitting element and the shading member are configured so that the illumination area does not overlap with the exit port or the area of ​​the portion overlapping with the exit port is less than half of the area of ​​the exit port.

2. The lens module according to claim 1, wherein: The first surface is convex or concave.

3. The lens module according to claim 1, wherein: The lighting module also includes an aperture, which cooperates with the light shielding member to form an annular groove so that the lighting light emitted by the light-emitting element can pass through.

4. The lens module according to claim 3, wherein: The projections of the annular groove and the light-emitting element on the plane where the first lens is located overlap.

5. The lens module according to claim 1, wherein: The second lens group has a second lens close to the first lens; a line connecting the edges of the first lens and the second lens on the same side is defined as a boundary line; the light-through groove is in a truncated cone shape, an angle between its generatrix and the optical axis is not less than an angle between the boundary line and the optical axis, and the boundary line is located between the generatrix and the optical axis.

6. The lens module according to claim 1, wherein: The light emitting elements include four first light emitting elements and four second light emitting elements, and the first light emitting elements and the second light emitting elements are arranged at intervals.

7. The lens module according to claim 6, wherein: The first light emitting element emits visible light, and the second light emitting element emits invisible light.

8. A fundus camera, characterized in that: The lens module comprises any one of claims 1 to 7.

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