WO2018010298A1 - Fundus camera and optical system thereof - Google Patents

Abstract

An optical system, comprising: an ocular objective lens (L₁), an imaging objective lens (L₂), an image sensor (4) for collecting a fundus image, and a visual marker (6) for human eye observation, disposed in that order. The visual marker (6) is disposed between the ocular objective lens (L₁) and the imaging objective lens (L₂). The optical system also comprises a semi-transparent semi-reflecting mirror (3), disposed between the ocular objective lens (L₁) and the imaging objective lens (L₂), for light splitting. The imaging objective lens (L₂) and the image sensor (4) are disposed, in that order, in a transmitted light path of the semi-transparent semi-reflecting mirror (3), and the image sensor (4) is placed at a position conjugated with a fundus. The visual marker (6) is disposed in a reflected light path of the semi-transparent semi-reflecting mirror (3) and is placed at a position conjugated with the fundus. The visual marker (6) and the image sensor (4) have the same conjugate distance. Also provided is a fundus camera comprising the optical system. Photographing a fundus with the camera of the invention does not require eye fixation and is easy to use.

Description

 Fundus camera and its optical system

Technical field

 The invention relates to the field of medical instruments, and particularly relates to a fundus camera and an optical system thereof.

Background technique

The fundus retinal vascular network is the only network of small arteries and venules that can be directly observed. It can directly reflect coronary heart disease, hypertension, diabetes and other diseases. The most common chronic complication of diabetic patients is diabetic retinopathy (Diabetic) Retinopathy, DR), the blindness rate is 25 times that of the general population. By examining whether the fundus produces vascular lesions, it is the main basis for early diagnosis of these diseases, early detection, early diagnosis, early prevention, effective treatment of patients before irreversible damage of the retina, so fundus screening has very important clinical significance. . The comparison of the normal retina and the diseased retina is shown in Figs. 1A and 1B, wherein Fig. 1A is a normal retinal image, and Fig. 1B is a diabetic retinopathy image.

At present, the fundus image is generally obtained by a fundus camera to observe and analyze the retina of the fundus. A conventional fundus camera has an eyepiece structure, and it is necessary to observe the fundus through an eyepiece to find a pathological region, and then collect a fundus image through a camera system. When collecting the fundus image, try to prevent the eyeball from rotating. The prior art usually uses the method of fixing the eyeball angle to prevent the eyeball from rotating. The fundus camera based on this method is mostly a desktop product, and the operation is professional, and the operator is required to have higher requirements. .

Summary of the invention

In view of the above problems, an object of the present invention is to provide a fundus camera and an optical system thereof which are easy to operate.

A technical solution adopted by the present invention is:

An optical system of a fundus camera, comprising a contact objective lens L1, an imaging objective lens L2 and an image sensor for collecting a fundus image, wherein the optical system further comprises an optotype for human eye observation. The optotype is disposed between the object objective lens L1 and the imaging objective lens L2.

Preferably, the optical system includes a focusing lens L1' disposed to be movable along the optical axis between the object objective lens L1 and the object.

Another technical solution adopted by the present invention is:

An optical system of a fundus camera, comprising a contact objective lens L1, an imaging objective lens L2 and an image sensor for acquiring a fundus image, which are sequentially disposed, the optical system further comprising an eyepiece lens L1 and the imaging objective lens L2 a half mirror for splitting light, an optotype for human eye observation, the imaging objective L2, an image sensor being sequentially disposed in a transmitted light path of the half mirror and the image sensor Located at a position conjugate with the fundus, the optotype is disposed in a reflected light path of the half mirror and located at a position conjugate with the fundus, the optotype being consistent with a conjugate distance of the image sensor .

Preferably, the optical system further includes an imaging objective lens L2', and the imaging objective lens L2', the visual target is sequentially disposed in the reflected light path of the half mirror.

More preferably, the optical system includes a mirror, the mirror, the imaging objective L2', and the optotype are sequentially disposed in the reflected light path of the half mirror.

More preferably, the optical parameters of the imaging objective lens L2 and the imaging objective lens L2' are identical.

Preferably, the optical system further includes a focus lens L1' movable along an optical axis, the focus lens L1' being disposed between the object objective lens and the half mirror.

Another technical solution adopted by the present invention is:

A fundus camera having the optical system described.

Preferably, the image sensor is connected to the display screen for displaying the collected fundus image on the display screen;

And/or, the image sensor is connected to a data transmitting device for transmitting the collected fundus image to the server or the terminal.

Preferably, the focusing lens L1' is disposed in a lens barrel, and the lens barrel is provided with scales corresponding to front view, near vision, and far vision.

The invention adopts the above technical solution, and has the following advantages compared with the prior art: the optical target is set in the optical path, and the eyeball naturally remains relatively immobile when the human eye observes the visual target, and the eyeball does not need to be fixed; according to the reversible principle of the optical path, the human eye can see clearly When the target is used, the fundus image can be imaged on the image sensor, which makes the operation convenient, and the fundus camera has a simple structure and is portable.

DRAWINGS

Figure 1A is a normal retinal image;

Figure 1B is a retinal image of a diabetic lesion;

Figure 2 is an optical system according to Embodiment 1 of the present invention;

Figure 3 is a schematic view of the lens barrel of the fundus camera of the present invention;

Figure 4 is an optical system of Embodiment 2 of the present invention.

Among them, 1, fundus; 2, eyelid; L1, eyepiece lens; L1', focusing lens; 3, half mirror; L2, imaging objective; 4, image sensor; 5, mirror; L2', Imaging objective; 6, visual target.

detailed description

The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings, in which the advantages and features of the invention can be more readily understood by those skilled in the art.

Example 1

Figure 2 shows a specific embodiment of the optical system of the fundus camera of the present invention. Referring to FIG. 2, the optical system includes an object objective lens L1, an imaging objective lens L2, and an image sensor 4. The fundus 1 generates a real image (intermediate image) at R via the object objective lens L1, and the real image is imaged via the imaging objective lens L2. On the image sensor 4, the image sensor 4 performs acquisition of a fundus image. An optotype 6 for human eye observation is also disposed in the optical path of the optical system. Specifically in this embodiment, the position of the optotype 6 is located at R between the object objective and the imaging objective. The optotype 6 should not be large enough to completely obscure the fundus 1 so that the image sensor 4 can capture the fundus 1 image, and the optotype 6 can be a cross or the like.

In practice, there are individual differences in the diopter of the human eye, and the differences tend to be large. The emmetropic eye is parallel light (equivalent to the infinity); the myopic eye is concentrated light (equivalent to the object is limited); the farsighted eye is divergent light (equivalent to the virtual object). The distance l0 from the fundus 1 to the pupil is different depending on the diopter of the human eye. Therefore, in order to compensate for the surface movement caused by the diopter error, the fundus camera uses a mechanical or optical compensation method to achieve clear imaging of the fundus 1 of the abnormal eye and the normal eye. In order to apply a different diopter of the subject (such as myopia, hyperopia and the like), the optical system of the embodiment is provided with a focusing lens L1' between the objective lens L1 and the target 6, and the focusing lens L1' can be Moving along the optical axis, with a large adjustment range.

The image sensor 4 is connected to a display screen (not shown) to transmit the image of the fundus 1 to the display screen for real-time observation and shooting; the image sensor 4 can also be connected to a data transmitting device (such as a wifi transmitting device). The collected fundus 1 image is sent to the server end of the telemedicine system for storage and analysis by the data transmitting device, or sent to the terminal of the PC or smartphone of the subject for storage and display.

The fundus camera includes the above optical system in which the focus lens L1' is disposed in the lens barrel. In order to facilitate the subject to quickly focus to find the best focal plane, as shown in FIG. 3, the lens barrel is provided with scales arranged along the optical axis corresponding to the front view, the near vision and the far vision. The focus lens L1' is moved to the myopia scale to compensate the diopter of the myopic subject; the focus lens L1' is moved to the far vision scale to compensate the diopter of the hyperopia subject.

The focus lens L1' is a lens group composed of a plurality of lenses, and the illumination mode that can be used for the fundus camera is not limited.

The principle of the optical system of the present embodiment is as follows: the optotype 6 is set at the R of the optical path, and the subject adjusts the focusing lens L1' according to its own diopter until the visual target 6 is seen. According to the reversible principle of the optical path, the fundus 1 is necessarily in the R A real image is generated, which is imaged on the image sensor 4 via the imaging objective lens L2; a focusing lens L1' is disposed between the object objective lens L1 and the visual target 6, and the position of the focusing lens L1' is adjusted to adjust the diopter. The examiner can see the visual target 6 (ie, adjust l1 and l2 according to the distance l0 of the fundus 1 to the eyelid 2), and ensure that the conjugate distances l3 and l4 of the imaging objective lens L2 remain unchanged, thereby making the structure of the fundus camera more In order to simplify the use of the fundus camera for civilian use, portability, and popularization, it is possible for the general public to check the fundus 1 in time, and obtain a correct diagnosis through the telemedicine system, thereby achieving a positive effect of early prevention and early treatment.

Example 2

Fig. 4 shows another specific embodiment of the optical system of the fundus camera of the present invention. The difference between this embodiment and the embodiment 1 is set at different positions in the optotype 6. Referring to Fig. 4, the optical system includes an object objective lens L1, a half mirror 3, an imaging objective lens L2, an image sensor 4, and a mirror 5, an imaging objective lens L2', and an optotype 6. The half mirror 3 is disposed to split between the object objective lens L1 and the imaging objective lenses L2 and L2', and the imaging objective lens L2 and the image sensor 4 are sequentially disposed in the transmitted light path of the half mirror 3 and the image sensor 4 is located and The position where the fundus 1 is conjugate with each other, the mirror 5, the imaging objective lens L2', and the optotype 6 are sequentially disposed in the reflected light path of the half mirror 3 and the optotype 6 is located at a position conjugate with the fundus 1 .

The human eye observes the optotype 6 through the reflection of the half mirror 3, and the image sensor 4 transmits the fundus image through the half mirror 3, and the imaging objective lens L2. The optical parameters of the imaging objective lens L2 and the imaging objective lens L2' are completely identical, such as a focal length and the like. The image sensor 4 and the optotype 6 are respectively located at positions where the two of the optical paths are conjugate with the fundus 1, the fundus 1 is conjugate with the image sensor 4 (the image relationship between the two), and the fundus 1 is conjugate with the optotype 6. (the two form image relationship), and the conjugate distance of both the image sensor 4 and the optotype 6 is the same, that is, the distance from the image sensor 4 to the fundus 1 in the optical path is the same as the distance from the optotype 6 to the fundus 1 in the optical path. . When the human eye sees the visual target 6, the fundus 1 can be imaged on the image sensor 4.

The focus lens L1' in this embodiment is disposed between the object objective lens L1 and the half mirror 3, and the focus lens L1' is movable along the optical axis, and has a large adjustment range.

The above embodiments are merely illustrative of the technical concept and features of the present invention, and are a preferred embodiment for the purpose of enabling those skilled in the art to understand the present invention and implement the present invention. The scope of protection. Equivalent variations or modifications made in accordance with the spirit of the invention are intended to be included within the scope of the invention.

Claims (10)

An optical system of a fundus camera, comprising a contact objective lens L1, an imaging objective lens L2 and an image sensor for collecting a fundus image, wherein the optical system further comprises an optotype for human eye observation. The optotype is disposed between the object objective lens L1 and the imaging objective lens L2. The optical system according to claim 1, characterized in that the optical system comprises a focus lens L1' which is movable between the object objective lens L1 and the object mark and movable along the optical axis. An optical system for a fundus camera, comprising an eyepiece lens L1, an imaging objective lens L2, and an image sensor for collecting a fundus image, which are sequentially disposed, wherein the optical system further comprises an eyepiece L1 and a device disposed at the eyepiece a half mirror for separating light between the imaging objective lens L2, an optotype for human eye observation, the imaging objective lens L2, the image sensor are sequentially disposed in the transmission optical path of the semi-transparent mirror and The image sensor is located at a position conjugate with the fundus, the optotype being disposed in a reflected light path of the half mirror and located at a position conjugate with the fundus, the optotype and the image sensor The conjugate distance is the same. The optical system according to claim 3, wherein said optical system further comprises an imaging objective lens L2', The imaging objective lens L2' and the visual target are sequentially disposed in the reflected light path of the half mirror. The optical system according to claim 4, wherein the optical system comprises a mirror, and the mirror, the imaging objective L2', and the optotype are sequentially disposed in the reflected light path of the half mirror. The optical system according to claim 4, characterized in that the optical parameters of the imaging objective lens L2 and the imaging objective lens L2' are identical. The optical system according to claim 3, wherein said optical system further comprises a focus lens L1' movable along an optical axis, said focus lens L1' being disposed at said object objective lens and said half Between the half mirrors. A fundus camera having the optical system of any of claims 1-7. The fundus camera according to claim 8, wherein the image sensor is connected to the display screen for displaying the collected fundus image on the display screen; And/or, the image sensor is connected to a data transmitting device for transmitting the collected fundus image to the server or the terminal. A fundus camera having the optical system according to claim 2 or 7, wherein the focus lens L1' is disposed in a lens barrel, and the lens barrel is provided with scales corresponding to front view, near vision, and far vision.