TW201838582A - Fundus photography device - Google Patents

Abstract

The present application discloses a fundus photography device with which position adjustment of a focus lens using invisible light, which is performed prior to performing fundus photography using visible light, can be performed without requiring complex control. The present invention provides a fundus photography device provided with: an image capture element sensitive to at least visible light and invisible light; a focus lens disposed partway along an optical path extending from the fundus of a subject's eye to the image capture element; a focus adjust means which projects a focus target using a second invisible light having a different peak wavelength from that of a first invisible light used for observing the fundus of the subject's eye, and which aligns the focus lens in a position at which a focus target image captured by means of the image capture element is focused; and an optical path correction member which is inserted or removed when an image of the fundus of the subject's eye is captured using visible light, and which corrects an optical path difference between visible light and invisible light traveling from the fundus of the subject's eye to the image capture element.

Description

Fundus photography device

The present invention relates to a fundus photography device.

In fundus photography using visible light, in order to prevent pupils from closing due to visible light shining on the fundus, invisible light, such as infrared light, which the eye does not perceive, is used to perform pre-adjustment between the eye to be inspected and the optical system ( Optical axis alignment, focusing, etc.) (for example, refer to Patent Document 1). [Habitual technical literature] [patent literature]

[Patent Document 1] Japanese Patent No. 5807701 [Patent Document 2] Japanese Patent No. 5215675 [Patent Document 3] International Publication No. 2016/136859

[Problems to be Solved by the Invention]

In the fundus imaging device, before the fundus photography, first, the position of the focus lens is adjusted. However, since visible light and invisible light have chromatic aberration, when the position of the focus lens is adjusted using invisible light, it is necessary to consider the deviation of the position of the focus lens due to chromatic aberration. However, adjusting the position of the focus lens corresponding to chromatic aberration complicates control of the operation mechanism of the focus lens.

Here, the fundus photography device of the present case can be realized without complicated control: before the fundus photography using visible light, the position of the focusing lens using invisible light is adjusted in advance. [Means to solve the problem]

In order to solve the above-mentioned problems, in the present invention, the imaging using an imaging element having sensitivity to at least visible light and invisible light, and fundus using visible light is in a state where the focusing lens is aligned at a position focused by invisible light. get on. The optical path difference between visible light and invisible light is corrected by inserting and removing the optical path correction member.

In detail, the fundus imaging device of the present invention includes: an imaging element having a sensitivity to at least visible light and invisible light; and a focusing lens disposed in the middle of the optical path from the fundus of the subject's eye to the imaging element; and The second invisible light, which is different from the first invisible light used for the observation of the fundus of the eye of the subject, projects the focusing optotype and focuses the focusing lens on the image of the focusing optotype obtained by the imaging element Means for adjusting the focusing position of the camera; and optical path correction for correcting the optical path difference between the visible light and the invisible light of the imaging element from the fundus of the subject's eye to the imaging element when the fundus of the subject's eye is photographed with visible light member.

Here, invisible light is light that cannot be perceived by human eyes, and for example, infrared light can be applied. The first invisible light is invisible light having a predetermined wavelength at the peak, and for example, infrared light having a wavelength of 850 nm as the peak can be applied. In addition, the second invisible light is invisible light having a wavelength different from a predetermined wavelength at the peak, and for example, infrared light having a wavelength of 805 nm as the peak can be applied.

The above-mentioned focus adjustment means of the fundus imaging device is to position the focus lens at a position where the image of the focus target projected by the second invisible light is focused. In addition, the fundus photography using visible light is performed in a state where the focusing lens is aligned at a position focused by invisible light. That is, in the operating mechanism of the focus lens, complicated control that takes into account chromatic aberration between visible light and invisible light is not performed. In addition, the focus position caused by the chromatic aberration between visible light and invisible light is adjusted by an optical path correction member that is detached during fundus photography using visible light. This adjustment is achieved by a simple operation of the insertion and removal of the optical path correction member, and therefore does not require the complicated control required for adjusting the position of the focus lens considering chromatic aberration.

Further, the above-mentioned focus adjustment means may be one in which the focus lens is positioned at the position where the image of the focus target obtained by the imaging element is focused when the first invisible light is turned off. If the aforementioned fundus imaging device is equipped with such a focus adjustment means, the focus optotype can be clearly captured.

In addition, the above-mentioned focus adjustment means is to use the first invisible light to perform fundus observation every 1 frame, and when the first invisible light is turned off, the focus lens is aligned with the image of the focus target obtained by the imaging element Anyone can focus. If the aforementioned fundus imaging device is equipped with such a focus adjustment means, it is possible to perform focus adjustment during fundus observation.

In addition, the above-mentioned optical path correction member may have a function of blocking invisible light. If the above-mentioned fundus imaging device is provided with such a light path correction member, invisible light will not be reflected in the photographic image of the fundus, so that a clear photographic image of the fundus can be obtained.

In addition, the fundus imaging device described above may include a plurality of optical path correction members corresponding to a plurality of types of lenses whose corresponding magnifications are exchanged. When the above-mentioned fundus imaging device is provided with such an optical path correction member, a more vivid photographic image of the fundus can be obtained. [Effect of the invention]

With the aforementioned fundus imaging device, it is possible to realize without complicated control: before the fundus photography using visible light, the position adjustment using the invisible light focusing lens is performed in advance.

Hereinafter, examples of the present invention will be described. The embodiment shown below is only an example of the embodiment of the present invention, and does not limit the technical scope of the present invention to the following aspects.

FIG. 1 is a diagram showing a schematic configuration of an optical system of a fundus imaging apparatus according to this embodiment. Fundus photographing device 1 is a device for photographing the fundus of the eye E to be inspected, and includes an objective lens 2, a perforated mirror 3, a focusing lens 4, a half mirror 5, an internal fixation lamp 6, a relay lens 7, and a pair of Focus mirror 8, focusing target projection system 9, black dot glass 10, relay lens 11, ring slit 12, diffuser 13, lighting 14 for photography, lighting 15 for observation, imaging lens 16, and narrow-angle lens 17. Wide-angle lens 18, optical path correction glass 19 (an example of the "optical path correction member" in this case), and image detector 20.

First, the positional relationship and function of each component provided in the fundus imaging device 1 will be described. The objective lens 2 is a lens located on the front side of the eye E to be examined. In addition, on the optical axis behind the objective lens 2, the perforated mirror 3, the focusing lens 4, the half mirror 5, and the internal fixation lamp 6 are arranged in order. The perforated mirror 3 is a mirror in which a through-hole is formed at a portion through which the optical axis of the objective lens 2 passes, and the optical axis of the objective lens 2 is fixed in the fundus imaging device 1 at an appropriate inclination angle.

On the axis of the illumination optical system that is guided by the illumination light reflected by the effective mirror and irradiated on the subject's eye E, a relay lens 7, a focus mirror 8, and a black spot are arranged in this order from the side of the perforated mirror 3. The plate glass 10, the relay lens 11, the annular slit 12, the diffusion plate 13, the photography illumination 14, and the observation illumination 15 are provided. Therefore, the light radiated from the photography illumination 14 and the observation illumination 15 is irradiated with light in the form of passing through the diffuser plate 13 and the annular slit 12, and passes through the relay lens 11, the black spot glass 10, The focus mirror 8 and the relay lens 7 are reflected by the perforated mirror 3 and illuminate the fundus of the eye E through the objective lens 2.

The black dot plate glass 10 is a user who prevents the reflected light generated by the objective lens 2 from being written into the photographic image. A small light shield is arranged at the center of the plate glass, that is, at the position of the optical axis. In the focus mirror 8 between the black spot plate glass 10 and the relay lens 7, the light from the in-focus target projection system 9 is incident from the reflected light at an angle that coincides with the optical axis of the relay lens 7. The focus optotype projection system 9 projects the focus optotype on the fundus of the eye E to be examined. Therefore, in addition to the light emitted from the photography illumination 14 and the observation illumination 15 in the fundus of the eye E to be inspected, the light of the focus optotype emitted from the focus optotype projection system 9 is also incident. The in-focus target projection system 9 is an infrared LED (Light Emitting Diode) that emits infrared light having a peak wavelength different from infrared light for fundus observation emitted by the observation illumination 15. The observation illumination 15 is a case where an infrared LED that emits infrared light with a peak wavelength of 850 nm is used as the light source, and the light source of the focus target projection system 9 is an infrared LED that emits infrared light with a peak wavelength of 805 nm .

The reflected light from the fundus of the eye E to be illuminated by the light of the photography illumination 14 and the observation illumination 15 is incident on the half mirror 5 through the objective lens 2, the perforated mirror 3, and the focusing lens 4. The half mirror 5 is fixed in the fundus imaging device 1 at an appropriate tilt angle with respect to the optical axis of the objective lens 2. Therefore, the reflected light from the fundus of the eye E to be inspected is reflected by the half mirror 5 at an appropriate angle to the optical axis of the objective lens 2. On the optical axis of the reflected light of the half mirror 5 incident from the focusing lens 4, an imaging lens 16, an optical path correction glass 19, and an image detector 20 are sequentially provided. In addition, a variable-magnification lens that is appropriately selected according to the viewer's desired magnification, that is, a narrow-angle lens 17 or a wide-angle lens 18, is inserted between the imaging lens 16 and the optical path correction glass 19. Therefore, the reflected light from the fundus of the eye E to be inspected is reflected by the half mirror 5, passes through the imaging lens 16, passes through the narrow-angle lens 17 or the wide-angle lens 18, and then enters the image detector 20. In the image detector 20, the photoelectric conversion elements arranged in an array form receive electrical energy and emit electrical signals to obtain an image of the fundus of the eye E to be inspected.

The image detector 20 is an imaging element having sensitivity to at least visible light and infrared light. Therefore, the image detector 20 can obtain an image of the fundus irrespective of whether the light source illuminating the fundus of the eye E to be inspected is any of the illumination 14 for photography and the illumination 15 for observation. In addition, the image detector 20 has a merging function that aggregates adjacent photoelectric change elements into one pixel for processing. Therefore, even if the image detector 20 reflects light from the fundus of the eye E to be inspected, which is illuminated by the observation illumination 15 having a lower illuminance than the illumination 14 for photography, it is possible to perform photosensitivity when obtaining the fundus image degree. The image detector 20 is, for example, CMOS.

However, the optical path correction glass 19 is inserted toward the optical path when the fundus of the eye E to be photographed is visible light, and is removed from the optical path when viewed with infrared light. The optical path correction glass 19 is a member that corrects the optical path difference between visible light and infrared light from the fundus of the eye E to the image detector 20, and is between visible light and infrared light that will be caused by chromatic aberration. The plate-shaped glass is prepared for the purpose of eliminating the deviation of the focal position of the fundus image. The optical path correction glass 19 preferably has a filter function that blocks infrared light. If the optical path correction glass 19 has a filter function for blocking infrared light, it is possible to prevent infrared light from being reflected in the fundus image. The optical path correction glass 19 has a filter function, and it is possible to suppress as much as possible the loss of the fundus image caused by infrared light before and after photography using visible light. Therefore, the optical path correction glass 19 can be inserted and removed instantly. good.

FIG. 2 is a block diagram of a circuit provided in the fundus photographing device 1. The fundus imaging device 1 includes a CPU substrate 21, an LCD panel 22 (Liquid Crystal Display), an LCD back light source 23, an operation unit 24, and a main substrate 25. In the second figure, the actuators that operate the focusing lens 4 and the optical path correction glass 19, the high-voltage circuit that emits the illumination 14 for photography, the LEDs provided in the focus target projection system 9, and the observation illumination 15 are all used as Electronic components 26 are shown together.

The CPU substrate 21 is mainly a circuit substrate for processing an image obtained by the image detector 20, and is mounted with a CPU (Central Processing Unit, Central Processing Unit) and FPGA (Field Programmable Gate Array) for image processing. And various electronic components such as a magnetic disk device for recording SD images (registered trademarks in Japan). The image detector 20 operates in response to a control signal from the CPU substrate 21 and supplies the acquired image to the CPU substrate 21. The CPU substrate 21 performs various processes on the image obtained by the image detector 20, and the processed image is output to the LCD panel 22 or the SD card. The LCD panel 22 displays an image output from the CPU substrate 21.

The main substrate 25 is a circuit substrate for controlling the management of the fundus imaging device 1 as a whole, and is mounted with an FPGA and various other electronic components. The main substrate 25 operates the CPU substrate 21 and the electronic components 26 in accordance with the operation content received by the operation unit 24. The main substrate 25 implements the following processing flow.

FIG. 3 is a diagram showing a processing flow realized by the fundus imaging device 1. When the shooting start operation is performed by the operation unit 24, the merge function of the video detector 20 becomes effective, and the merge processing of the video detector 20 is started (S101). Then, the observation illumination 15 is energized, and the infrared LEDs of the observation illumination 15 start to emit light synchronously (S102). Then, the infrared LED of the focus target projection system 9 starts emitting light (S103). Here, synchronous light emission is to repeatedly emit light and turn off the light at the time when the image detector 20 scans one frame. Therefore, in the synchronous emission of the observation illumination 15, the image of the eye E obtained by the image detector 20 is the fundus image illuminated by the observation illumination 15 and the fundus image not illuminated by the observation illumination 15 A collection of portraits that are interactively juxtaposed along the time axis. Since the infrared LEDs of the focus target projection system 9 always light up even during the synchronous emission of the infrared LEDs of the observation illumination 15, the image of the eye E obtained by the image detector 20 is acquired by the synchronous emission of the observation illumination 15. Regardless of whether the fundus is illuminated by the observation light 15, the focus optotypes will be reflected.

FIG. 4 is a diagram showing a time chart of each process realized when the wide-angle lens 18 is selected. When the shooting start operation is performed with the wide-angle lens 18 selected, as shown in the timing chart of FIG. 4, in addition to the integration process of the image detector 20, the infrared LEDs generated by the observation illumination 15 are also started. The light is emitted synchronously, and the emission of the infrared LED of the focus target projection system 9 starts. Therefore, the video detector 20 acquires the following video.

FIG. 5 is a diagram showing an example of an image acquired by the image detector 20. When the imaging start operation is started and the synchronous light emission by the infrared LED of the observation illumination 15 and the light emission of the infrared LED of the focus target projection system 9 are started, the image detector 20 is obtained as shown in FIG. 5. The fundus image illuminated by the illumination 15 (refer to the even-numbered cell in FIG. 5) and the fundus image not illuminated by the observation illumination 15 (refer to the odd-numbered cell in FIG. 5) are alternately repeated images. Since the infrared LEDs of the focusing target projection system 9 always light up even during the synchronous emission of the infrared LEDs of the observation illumination 15, as shown in FIG. 5, in the image obtained by the image detector 20, the focusing target 30 is horizontal. The whole frame is reflected. Further, in the image acquired by the image detector 20, in addition to the focus optotype 30, a WD indicator 31 (WD: Working Distance) is reflected.

FIG. 6 is a diagram showing an example of an image displayed on the LCD panel 22. When the image detector 20 starts acquiring an image, the CPU substrate 21 performs a process of sending out only the fundus image illuminated by the observation illumination 15 to the LCD panel 22. Thus, for example, as shown in FIG. 6, the LCD panel 22 displays the fundus images illuminated by the observation illumination 15 as continuous images. In this case, as shown in Fig. 5, it becomes an image of an even-numbered grid frame separated by an interval of 2nd, 4th, and 6th frames ‧‧‧ as shown in Fig. 5, but it is not necessary to be a target The image display of all the frames may be displayed at intervals of the second frame, the sixth frame, and the tenth frame.

Referring to the flowchart in FIG. 3 again, the processing after step S104 will be described. The fundus photographing device 1 is provided with an autofocus function and an auto-irradiation function, and can automatically adjust the focus lens 4 and the like by electronic control. However, in the fundus photographing device 1 of this embodiment, among the narrow-angle lens 17 and wide-angle lens 18 that are appropriately selected by the observer in accordance with the observation site, the narrow-angle lens 17 is selected by the autofocus function and automatic The irradiation function becomes invalid. The reason for this is that the optic nerve papilla with the narrow-angle lens 17 selected and more likely to be observed has a higher reflectance than the so-called fundus portion, so the focus optics are projected onto the optic nerve papilla. The brightness of the subject is unstable compared with the fundus portion, and there is a possibility that the autofocus function cannot operate normally. Therefore, as shown in the flowchart of FIG. 3, in the fundus imaging device 1 of this embodiment, the processing of the autofocus function and the auto-irradiation function is performed when the wide-angle lens 18 is selected (step S105 to step to be described later). The processes up to S107) are performed when the narrow-angle lens 17 is selected (processes from step S108 to step S109 to be described later).

That is, after performing the process of step S103 in the fundus imaging apparatus 1, it is determined whether the wide-angle lens 18 is selected (S104). When the wide-angle lens 18 is inserted between the imaging lens 16 and the optical path correction glass 19, an affirmative determination is made in the process of step S104. When the narrow-angle lens 17 is inserted between the imaging lens 16 and the optical path correction glass 19, a negative determination is made in the process of step S104. Whether or not any of the wide-angle lens 18 and the narrow-angle lens 17 is selected is detected by a contact switch or the like provided in the lens switching mechanism.

After an affirmative determination is made in step S104, a determination is made as to whether the focus is consistent (S105), and if the focus is not consistent, the motor of the focus lens 4 is appropriately operated (S106). After step S106 is performed, the processing after step S104 is performed again. If it is determined that the focus is consistent in the process of step S105, it is then determined whether the position and size of the WD indicator 31 are within a predetermined range (S107).

After the negative determination is made in step S104, the autofocus function and the automatic irradiation function are invalidated (S108), and it is determined whether the shutter switch is pushed by the operation unit 24 (S109).

However, in step S105, the discrimination processing is performed as follows. That is, when the image detector 20 starts acquiring an image, the CPU board 21 performs the process of sending only the fundus image illuminated by the observation illumination 15 as described above to the LCD panel 22 and using the illumination without the observation illumination 15. Detection processing of the focus optotype 30 of the fundus image. FIG. 7 is a diagram showing an example of an image in which the fundus images used in the detection process of the focus optotype 30 are juxtaposed. In the determination processing of whether the focus is consistent in step S105, in order to easily detect the focus optotype 30, a fundus image that is not reflected in the background of the focus optotype 30 is used. In this case, although it is an image of an odd-numbered grid spaced at an interval of each of the first, third, and fifth frames ‧‧‧ as shown in FIG. 5, it is not necessary to be a target. The portraits of all the frames show that the interval between the first frame, the fifth frame, and the ninth frame is not a problem.

Whether the focus is consistent is determined as follows. FIG. 8 is a first diagram showing a method of determining focus. In the determination of whether the focus is consistent, first, as shown in FIG. 8, the position (y coordinate) of the upper and lower ends of the focus optotype 30L within the discrimination range 32L on the left and the focus optotype 30R within the discrimination range 32R on the right The upper and lower end positions (y-coordinates) are extracted.

FIG. 9 is a second diagram showing a method of determining focus. The positions of the upper and lower ends of the focus optotypes 30L and 30R within the discrimination ranges 32L and 32R are obtained, for example, as follows. That is, the sum of the luminance of 10 pixels adjacent to each other in the x-axis direction is calculated at each y-coordinate, and the coordinates of the portion where the sum of the luminance becomes 75% of the peak of the luminance are taken as the upper and lower ends of the focus optotypes 30L and 30R. Get coordinates.

FIG. 10 is a third diagram showing a method of determining focus. After the coordinates of the upper and lower ends of the focus optotypes 30L and 30R within the discrimination ranges 32L and 32R are obtained, the center y coordinates of the upper and lower ends of the focus optotype 30L and the focus optotype 30R are calculated, respectively. If the difference between the center y coordinate of the focus optotype 30L and the center y coordinate of the focus optotype 30R is not 0, a negative determination is made in step S105, and the motor of the focus lens 4 is made so that the difference becomes 0 in step S106. It is appropriately operated. If the difference is 0, an affirmative determination is made in step S105.

In this embodiment, as described above, when the wide-angle lens 18 is selected, the autofocus function and the auto-irradiation function are effective, but the fundus imaging device 1 is not limited to this. The fundus imaging device 1 is, for example, irrespective of whether the wide-angle lens 18 is selected, the processes from step S105 to step S107 described above may be implemented, or the autofocus function and the automatic irradiation function may be abolished and the above step S108 may be eliminated. The processing up to step S109 may be implemented in the selection of the wide-angle lens 18. As in the former case, the processing of steps S105 to S107 is also realized in the selection of the narrow-angle lens 17. For example, the selection of the narrow-angle lens 17 is performed by focusing the infrared projection of the target projection system 9 The brightness is reduced, and the brightness of the focusing optotype projected on the optic nerve nipple is changed to suppress the possibility that the autofocus function cannot operate normally.

Referring to the flowchart in FIG. 3 again, the processing after step S110 will be described. After an affirmative determination is made in the processing of step S107 or step S109 described above, preparations for fundus photography are performed in order to obtain a sharp, high-resolution image of the fundus illuminated by the photographic illumination 14 having sufficient brightness. That is, the integration processing of the image detector 20 is stopped (S110), the observation illumination 15 is turned off (S111), and the infrared LED of the focus target projection system 9 is turned off (S112). The optical path correction glass 19 is inserted between the wide-angle lens 18 and the image detector 20 (S113), and the image detector 20 performs photographing of the fundus at the same time as the illumination of the photography illumination 14 (S114).

The optical path correction glass 19 is inserted for the following reasons. Fig. 11 is a first diagram comparing the in-focus positions. In the optical system of the fundus imaging device 1, chromatic aberration is an element that cannot be ignored for photographing the fundus clearly. For example, as shown in FIG. 11 (A), when the position of the focusing lens 4 is adjusted by infrared light, the optical path correction glass 19 is not inserted between the wide-angle lens 18 and the image detector 20, and visible light , As shown in FIG. 11 (B), focusing at a position far from the image detector 20. On the other hand, consider the case where the chromatic aberration of infrared light and visible light causes the thickness and the selected optical path correction glass 19 to be inserted between the wide-angle lens 18 and the image detector 20. The visible light is as shown in Figure 11 ( C) Focus on the surface of the image detector 20 as shown. Therefore, the image detector 20 is capable of capturing a sharp image of the fundus illuminated by the imaging illumination 14 that emits visible light.

When the wide-angle lens 18 is selected, the content of the processing performed by the fundus imaging device 1 is as described above. Next, the content of processing performed by the fundus imaging device 1 when the narrow-angle lens 17 is selected will be described.

FIG. 12 is a diagram showing a time chart of each process realized when the narrow-angle lens 17 is selected. When the shooting start operation is performed with the narrow-angle lens 17 selected, as shown in the timing chart of FIG. 12, the combination processing of the image detector 20 and the synchronous emission of the observation illumination 15 and the projection of the focus target are started. The light emitted from the system 9 is illuminated by the observation light 15 and the fundus image is a continuous image displayed on the LCD panel 22. Then, as shown in the flowchart in FIG. 3, a negative determination is performed in the process of step S104, and the autofocus function and the automatic irradiation function are invalidated (S108). Then, it is determined whether the shutter switch is pushed by the operation unit 24 (S109). If an affirmative determination is made in step S109, a series of processes from step S110 to step S114 described above are completed and the fundus photography is performed.

Fig. 13 is a second diagram comparing the in-focus positions. In the case where the narrow-angle lens 17 is selected, the chromatic aberration in the optical system possessed by the fundus imaging device 1 becomes more significant than when the wide-angle lens 18 is selected. That is, comparing the focus position shown in FIG. 11 and the focus position shown in FIG. 13 shows that when the narrow-angle lens 17 is selected, the position of the focus lens 4 is adjusted by infrared light. (See FIG. 13 (A)), visible light is focused at a position far from the image detector 20 as shown in FIG. 13 (B). Here, the optical path correction glass 19 between the wide-angle lens 18 and the image detector 20 is inserted when the narrow-angle lens 17 is selected, and the wide-angle lens 18 and the image are inserted when the wide-angle lens 18 is selected. The optical path correction glass 19 between the detectors 20 may be different in thickness or tortuosity. When the optical path correction glass 19 is switched according to the characteristics of the lens disposed between the imaging lens 16 and the optical path correction glass 19, visible light can be focused on the surface of the image detector 20 as shown in FIG. 13 (C).

Although the description of the fundus imaging device 1 is as described above, the fundus imaging device 1 is not limited to the above. The fundus imaging device 1 may be, for example, an infrared LED that emits infrared light other than the above-mentioned wavelengths in the in-focus target projection system 9 and the observation illumination 15. In addition, the fundus imaging device 1 may be, for example, a lens with a perforated mirror 3 and a half mirror 5 inclined at an angle different from the optical axis shown in FIG. 1.

1‧‧‧ fundus photography device

2‧‧‧ object lens

3‧‧‧ Perforated mirror

4‧‧‧ Focusing lens

5‧‧‧ half mirror

6‧‧‧ Internal Fixation Light

7‧‧‧ relay lens

8‧‧‧ focus mirror

9‧‧‧Focus Vision Projection System

10‧‧‧Black Dot Plate Glass

11‧‧‧ relay lens

12‧‧‧Ring slit

13‧‧‧ diffuser

14‧‧‧Photographic Lighting

15‧‧‧observation lighting

16‧‧‧ imaging lens

17‧‧‧ Narrow Angle Lenses

18‧‧‧wide-angle lens

19‧‧‧ light path correction glass

20‧‧‧Image Detector

21‧‧‧CPU board

22‧‧‧LCD Panel

23‧‧‧LCD back light source

24‧‧‧Operation Department

25‧‧‧Main board

26‧‧‧Electronic parts

30, 30L, 30R‧‧‧focus sight

31‧‧‧WD indicator

32L, 32R‧‧‧Discrimination range

E‧‧‧Eye examined

[FIG. 1] A diagram showing a schematic configuration of an optical system of a fundus imaging apparatus according to this embodiment.第 [Fig. 2] A block diagram of a circuit provided in the fundus photography device. [Fig. 3] A diagram showing a processing flow realized by a fundus imaging device. [Fig. 4] A diagram showing a time chart of each process realized when a wide-angle lens is selected. [Fig. 5] A diagram showing an example of an image obtained by an image detector. [Fig. 6] A diagram showing an example of an image displayed on the LCD panel. [Fig. 7] A diagram showing an example of an image in which the fundus images used in the detection process of the focus target are juxtaposed. [Fig. 8] Fig. 1 shows the method of determining the focus. [Fig. 9] Fig. 2 shows the method of determining the focus. [Fig. 10] Fig. 3 shows the method of determining the focus. [Figure 11] Figure 1 comparing the focus position. [Fig. 12] A diagram showing a time chart of each process realized when a narrow-angle lens is selected. [Figure 13] Figure 2 comparing the focus position.

Claims (7)

A fundus photographing device comprising: (ii) an imaging element having a sensitivity to at least visible light and invisible light; and a focusing lens arranged at a part of the optical path from the fundus of the subject's eye to the aforementioned imaging element; and the peak wavelength is The second invisible light, which is different from the first invisible light used for the observation of the fundus of the subject's eyes, projects a focusing optotype and focuses the focusing lens on an image of the focusing optotype obtained by the imaging element. Means for adjusting focus at the position; and inserting and removing the fundus of the subject's eye with visible light, and correcting a difference in optical path between visible light and invisible light of the subject's eye fundus to the image sensor Optical path correction member. For example, the ocular fundus photographing device according to item 1 of the patent application, wherein the focus adjustment means is to position the focus lens at a position where the image of the focus target obtained by the image sensor is focused when the first invisible light is turned off. . For example, the fundus photographing device according to item 1 or 2 of the scope of patent application, wherein the aforementioned focus adjustment means is to turn off the first invisible light when the first invisible light is observed at each frame of the fundus, and the first invisible light is turned off. At the time, the focusing lens is aligned at a position where the image of the focusing target obtained by the imaging element is focused. For example, the fundus photographing device according to item 1 or 2 of the patent application scope, wherein the aforementioned optical path correction member has a function of blocking the aforementioned invisible light. For example, the fundus photographing device according to item 1 or 2 of the patent application scope, wherein the aforementioned fundus photographing device is provided with a plurality of the aforementioned optical path correction members corresponding to a plurality of types of lenses whose corresponding magnifications are exchanged, respectively. For example, the fundus photography device according to item 1 or 2 of the patent application scope, wherein the aforementioned invisible light is infrared light. For example, the fundus photographing device according to item 1 or 2 of the patent application scope, wherein: the first invisible light is infrared light having a wavelength of 850 nm as a peak, and the second invisible light is infrared light having a wavelength of 805 nm as a peak.