JP7302342B2 - Fundus camera - Google Patents

Description

The present disclosure relates to a fundus imaging device for obtaining a front image of the fundus.

A fundus photographing apparatus for photographing a front image of the fundus of an eye to be examined is widely used in the field of ophthalmology. Examples of the fundus imaging device include a fundus camera, a scanning laser ophthalmoscope, and the following devices. For example, in Patent Document 1, a front image of the fundus is obtained by scanning the fundus with a slit-shaped illumination light and sequentially projecting the image of the illuminated fundus area onto a two-dimensional imaging surface according to the scanning. An apparatus is disclosed. In many fundus imaging devices, illumination light is projected and received through an objective lens.

Japanese Patent Publication No. 61-48940

In devices with an objective lens, under at least some imaging conditions, reflected light from the front or back surface of the objective lens can appear as artifacts in the fundus image. The artifact appears as a bright spot image (reflection image) near the center of the fundus image. A bright spot image can be an obstacle to diagnosis and observation.

The present disclosure has been made in view of at least one of the problems of the conventional technology, and a technical problem thereof is to obtain a fundus image in which artifacts are suppressed.

A fundus imaging apparatus according to a first aspect of the present disclosure includes an irradiation optical system that irradiates a slit-shaped illumination light to the fundus of an eye to be inspected through an objective lens, the irradiation optical system and the objective lens are shared, and a photographing optical system including a light receiving optical system having an imaging surface on which an image of the fundus is formed based on the fundus reflected light of the illumination light; and a scanning unit ; and the slit-shaped illumination light provided in the photographing optical system. or to form a local imaging area on the fundus of the eye, and a lens disposed between the objective lens and the diaphragm, wherein the dioptric power in the imaging optical system is and a dioptric correction optical system that corrects by moving the lens according to the refractive power of the eye to be examined, wherein the diaphragm is positioned at a position different from the fundus conjugate position with respect to both the objective lens and the dioptric correction optical system. A fundus image is taken in the arranged state.

A fundus imaging apparatus according to a second aspect of the present disclosure includes an illumination optical system that illuminates the fundus of an eye to be inspected with illumination light through an objective lens, the objective lens shared with the illumination optical system, and the illumination light and a light-receiving optical system having a light-receiving element that receives the reflected light of the fundus of the eye, and a fundus imaging apparatus that acquires a fundus image based on a signal from the light-receiving element, and is arranged in the irradiation optical system. and a second lens which is a second lens different from the first lens and arranged in the light receiving optical system, and by moving the first lens and the second lens respectively, the a diopter correction optical system that independently adjusts an irradiation side correction amount that is a diopter correction amount in the irradiation optical system and a light receiving side correction amount that is the dioptric correction amount in the light receiving optical system;
and control means for controlling the diopter correction optical system and setting the irradiation-side correction amount and the light-receiving side correction amount to mutually different values.

According to the present disclosure, it is possible to obtain a fundus image with suppressed artifacts.

It is a figure showing the appearance composition of the device concerning one example. It is an optical system accommodated in an imaging unit, Comprising: It is the figure which showed the optical system of 1st Example. 3 is a block diagram showing a control system of the device according to the embodiment; FIG. FIG. 10 is a diagram for explaining the operation of the dioptric correction optical system according to the refractive power of the subject's eye, and shows the state of dioptric correction when the refractive power is in the first range. FIG. 10 is a diagram for explaining the operation of the diopter correction optical system according to the refractive power of the subject's eye, and shows the state of diopter correction when the refractive power is in the second range. FIG. 5 is a diagram for explaining adjustment control of a diopter correction value in consideration of pupil size in addition to the refractive power of an eye to be inspected; FIG. 11 is a diagram for explaining an outline of second artifact suppression processing; FIG. FIG. 11 is a diagram for explaining an overview of a third artifact suppression process; FIG. 3A and 3B are diagrams showing a mode of irradiation and scanning of the fundus with illumination light by the optical system of FIG. 2; FIG. 3A and 3B are diagrams showing a mode of irradiation and scanning of the fundus with illumination light by the optical system of FIG. 2; FIG. FIG. 10 is a diagram for explaining the outline of the fourth artifact suppression process, and shows a fundus image obtained when illumination light is emitted from two light projection areas simultaneously; FIG. 12 is a diagram for explaining the outline of the fourth artifact suppression process, and shows a fundus image obtained when illumination light is selectively emitted from one of the two light projection areas; FIG. 12 is a diagram for explaining an outline of a fifth artifact suppression process; FIG. FIG. 3 is a diagram showing an optical chopper applicable as a scanning unit in the optical system of FIG. 2; FIG. 20 is a diagram for explaining the outline of the sixth artifact suppression process, and particularly shows an example using an optical chopper in which a plurality of slits with different widths are formed; FIG. 10 is a diagram showing an optical system of a second embodiment, which is an optical system housed in the photographing unit; It is a flow chart which shows the photography operation of an apparatus.

"overview"
An embodiment of a fundus imaging apparatus according to the present disclosure will be described below with reference to the drawings. Below, in each of the first to third embodiments, an apparatus that suppresses artifacts caused by reflection/scattering inside the eye or inside the apparatus will be disclosed. Each embodiment can utilize part or all of other embodiments as appropriate.

<First embodiment>
First, the first embodiment will be described. In the first embodiment, the fundus imaging device (see FIG. 1) has at least an imaging optical system (see FIG. 2, for example) and a controller (see FIG. 3, for example). The fundus imaging device may additionally have a refractive power information acquisition unit.

<Control section>
The control unit is a processing device (processor) that performs control processing of each unit in the fundus imaging apparatus and arithmetic processing. For example, the control unit is implemented by a CPU (Central Processing Unit), a memory, and the like. In this embodiment, the control unit may also serve as an image processing unit (imaging processor). The image processing unit generates a fundus image and executes at least one of various image processing on the fundus image.

<Photographing optical system>
The imaging optical system is used to project and receive illumination light to and from the fundus of the subject's eye via the objective lens to capture a fundus image. In the first embodiment, the imaging optical system has an irradiation optical system, a light receiving optical system, and a dioptric correction optical system (see FIGS. 2, 4A, and 4B).

The illumination optical system illuminates the fundus of the subject's eye with illumination light through the objective lens. Additionally, the illumination optics may have a light source that emits illumination light (illumination light source). The light receiving optical system has a light receiving element that receives the fundus reflected light of the illumination light. The light receiving optical system forms an image of the fundus on the imaging surface based on the fundus reflected light of the illumination light. A signal from the light receiving element is input to the image processing section. The image processing unit acquires (generates) an image formed on the imaging surface as a fundus image based on the signal from the light receiving element. In addition, in the present disclosure, the front image of the fundus is referred to as a “fundus image”.

The irradiation optical system and the light receiving optical system share at least an objective lens. In addition, the irradiation optical system and the light receiving optical system may share an optical path coupling section. The optical path coupling unit couples and separates the projection optical path of the illumination light and the reception optical path of the fundus reflected light. In this case, the objective lens is arranged on the common optical path of the light-projecting optical path and the light-receiving optical path formed by the optical path coupling section.

The imaging optical system may be a scanning optical system that performs imaging by scanning illumination light on the fundus. Also, the imaging optical system may be a non-scanning optical system. Examples of scanning optical systems include a spot scanning optical system and a line scanning optical system. In the spot scan type optical system, a spot-shaped illumination light is two-dimensionally scanned on the fundus. In the line scan type optical system, linear illumination light is scanned in one direction. For example, the line-shaped illumination light may be linearly scanned on the fundus or may be rotationally scanned on the fundus. In the case of rotational scanning, the center of rotation may be the optical axis of the imaging optical system (hereinafter also referred to as the "imaging optical axis"). In the scanning optical system, any one of a point light receiving element, a line sensor, a two-dimensional light receiving element (imaging element) and the like can be appropriately adopted as the light receiving element. An example of a non-scanning optical system includes an optical system of a general fundus camera.

<Diopter correction optical system>
The dioptric correction optical system (see FIGS. 2, 4A, and 4B) is used to correct the dioptric power of the imaging optical system according to the refractive power of the subject's eye. The refractive power of the subject's eye is also referred to as refractive error and diopter value. In this embodiment, the diopter correction optical system includes a diopter correction amount in the irradiation optical system (hereinafter referred to as "irradiation side correction amount") and a diopter correction amount in the light receiving optical system (hereinafter referred to as "light receiving side correction amount"). ) and are adjusted independently.

The dioptric correction optical system may be arranged separately at two or more locations in the imaging optical system. In this case, the dioptric correction optical system may have a first dioptric correction optical system and a second dioptric correction optical system. The dioptric correction amount in the first dioptric correction optical system and the dioptric correction amount in the second dioptric correction optical system are set independently. For example, the first dioptric correction optical system may be arranged on one of the optical paths of the irradiation optical system and the light receiving optical system. Alternatively, it may be arranged on a common optical path between the irradiation optical system and the light receiving optical system.

The present embodiment may have a first driving section (first driver) and a second driving section (second driver). The first driving section and the second driving section are independently controlled by the control section. The first driving section drives at least one optical element included in the first dioptric correction optical system. Also, the second driving section drives at least one optical element included in the second dioptric correction optical system.

When the second dioptric correction optical system is arranged in the common optical path, the dioptric correction amount in the other optical system is equal to the dioptric correction amount in the first dioptric correction optical system and the dioptric correction amount in the second dioptric correction optical system. It is determined by the sum of the diopter correction amount in For convenience of explanation, one or both of the first dioptric correction optical system and the second dioptric correction optical system that affect the dioptric power of the irradiation optical system will be referred to as an "irradiation side dioptric correction optical system". One or both of the optical systems that affect the dioptric power may be referred to as a "light-receiving dioptric correction optical system."

By the way, the position conjugated to the fundus with respect to the objective lens (that is, the position of the intermediate image plane of the fundus) is displaced according to the refractive power (mainly the spherical power) of the eye to be examined. 4A and 4B, the position of the intermediate image plane is denoted by J. As shown in FIG. In the present embodiment, the dioptric correction optical system arranged between the objective lens and the imaging plane is driven so that the intermediate image plane and the imaging plane of the light receiving optical system are in a conjugate relationship. image is well formed on the imaging plane.

In the present disclosure, "conjugated" is not necessarily limited to a perfect conjugated relationship, but includes "substantially conjugated". That is, the "conjugated" in the present disclosure also includes the case where the parts are displaced from the perfectly conjugated position within the allowable range in relation to the technical significance of each part.

Also, if the diopter correction is performed in the irradiation optical system, it is considered that, for example, errors in the illumination range can be suppressed, and the light intensity distribution of the illumination light on the fundus can be easily made uniform. However, the condensing position in the irradiation optical system is displaced along the optical axis according to the irradiation-side correction amount. Specifically, as the irradiation-side correction amount shifts toward the minus diopter side, the condensing position is considered to approach the objective lens. In addition, in FIG. 4A and FIG. 4B, the condensing position is shown with the code|symbol K. FIG. When the light-condensing position approaches the surface of the objective lens (that is, the front surface or the rear surface), the reflection of the illumination light by the objective lens may easily appear in the fundus image as an artifact. In other words, if the irradiation-side correction amount is adjusted according to the refractive power, the more the refractive power of the eye to be examined is closer to the minus diopter side (for example, the higher the refractive power of the eye is, the higher the myopia is). Artifacts are more likely to occur.

<Artifact Suppression by Mismatching the Correction Amount on the Irradiation Side and the Correction Amount on the Light Receiving Side>
On the other hand, the control unit may adjust the irradiation-side correction amount and the light-receiving-side correction amount to different values by controlling the diopter correction optical system (see FIG. 4B). For example, the controller may adjust the light-receiving side correction amount according to the refractive power of the eye to be examined. More specifically, the light-receiving side correction amount may be adjusted to a diopter that is substantially the same as the refractive power.

At this time, the controller may further adjust the condensing position of the illumination light via the dioptric correction optical system on the basis of the intermediate image of the fundus formed via the objective lens (see FIG. 4B). More specifically, the irradiation-side correction amount may be adjusted such that the condensing position is further away from the objective lens with respect to the intermediate image. As a result, the image of the fundus can be easily formed on the imaging surface, and the occurrence of artifacts due to the reflection of the objective lens can be suppressed. As a result, a good fundus image is captured.

At this time, the irradiation-side correction amount may be adjusted so as to have a smaller absolute value than the light-receiving-side correction amount. As the difference between the irradiation-side correction amount and the light-receiving-side correction amount increases, various effects such as a decrease in the amount of received light are more likely to occur. Therefore, each correction amount is limited so that a large difference does not occur between the irradiation-side correction amount and the light-receiving side correction amount, thereby obtaining a good-quality fundus image while suppressing the occurrence of artifacts. can be done.

When adjusting the irradiation-side correction amount and the light-receiving-side correction amount to different values, the control unit may adjust the irradiation-side correction amount to a constant value regardless of the light-receiving-side correction amount. However, it is not necessarily limited to this, and in the same case, the irradiation-side correction amount may be adjusted to a different value for each light-receiving-side correction amount.

However, it is not always necessary to adjust each photographing so that the irradiation-side correction amount and the light-receiving-side correction amount have different values. For example, under predetermined imaging conditions, the irradiation-side correction amount and the light-receiving-side correction amount may match each other. Here, imaging conditions under which artifacts do not pose a problem can be investigated in advance through experiments, optical simulations, and the like. For example, a range of diopter correction amounts in which artifacts do not occur when the irradiation-side correction amount and the light-receiving-side correction amount are matched may be determined in advance as an imaging condition. When the irradiation-side correction amount and the light-receiving-side correction amount match each other, each of the irradiation-side correction amount and the light-receiving-side correction amount may be adjusted to have substantially the same diopter as the refractive power.

<Switching the shooting mode according to the degree of refraction>
In this embodiment, the controller may switch the imaging mode of the apparatus between the first imaging mode and the second imaging mode according to the refractive power of the subject's eye. In the second shooting mode, the diopter correction optical system is controlled so that the "difference value" is larger than in the first shooting mode. The difference value here indicates the difference between the irradiation-side correction amount and the light-receiving side correction amount. As an example, in the first photographing mode, photographing may be performed with the irradiation-side correction amount and the light-receiving side correction amount being matched with each other (see FIG. 4A). In this case, both the irradiation-side correction amount and the light-receiving side correction amount may be adjusted to values according to the refractive power. Further, in the second photographing mode, photographing may be performed in a state in which the irradiation-side correction amount and the light-receiving side correction amount are different from each other (see FIG. 4B). In this case, as an example, the control unit may adjust the light-receiving side correction amount according to the refractive power of the eye to be examined, and set the irradiation-side correction amount to a value with a smaller absolute value than the light-receiving side correction amount. good.

The refractive power of the subject's eye may be broadly divided into a first range and a second range on the negative diopter side with respect to the first range. In the second range, with respect to the first range, the intermediate image plane of the fundus reflected light formed via the objective lens (mainly the intermediate image plane formed closest to the objective lens) is The range is closer to the rear surface of the objective lens. In FIGS. 4A and 4B, the range of the diopter correction amount corresponding to the first range is the range indicated by symbol A1. Also, the range of the dioptric power correction amount corresponding to the second range is the range indicated by symbol A2.

The shooting mode may be switched between when the refractive power is in the first range and when it is in the second range. The controller may switch to the first imaging mode when the refractive power is within the first range. Further, the control unit may switch to the second imaging mode when the refractive power is within the second range.

The values of refractive power that serve as thresholds for the first range and the second range can be checked in advance by, for example, experiments and optical simulations. For example, when the diopter correction amount in the diopter correction optical system is changed from the plus diopter side to the minus diopter side while matching the irradiation side correction amount and the light receiving side correction amount, A value at which artifacts start to occur may be defined as a threshold.

<Scanning type imaging optical system>
By the way, as a scanning type photographing optical system, a device having a harmful light removing section and a scanning section is known. In a scanning-type imaging optical system, an irradiation optical system forms a local illumination area in a part of the imaging range on the fundus. A typical example is a device that forms a slit-like or spot-like illumination area.

The harmful light removal section is arranged on the optical path of the light receiving optical system, for example, with the dioptric correction optical system interposed between it and the objective lens. In this case, the harmful light removal unit may be arranged at a position conjugate with at least the objective lens and the dioptric correction optical system to the fundus when the light receiving side correction amount is set according to the refractive power of the subject's eye.

The harmful light removing unit causes the light receiving element to receive fundus reflected light from a local imaging area (hereinafter referred to as "effective area") that is part of the imaging range. Also, the harmful light removing section is used to remove light from outside the effective area. The harmful light removing section may be, for example, a diaphragm. A typical aperture in a spot scan type device is a pinhole, and a typical aperture in a slit scan type device is a slit. In this case, the fundus reflected light from the effective area corresponding to the aperture of the diaphragm is selectively guided to the light receiving element and acquired as an effective image. In particular, in a slit scan type apparatus, the light receiving element itself may be used as a harmful light removing section. In this case, a line sensor may be used as the light receiving element, or a CMOS having a rolling shutter function may be used. The line sensor itself has a slit shape. Also, in a CMOS having a rolling shutter function, line exposure is performed on a two-dimensional imaging plane. The fundus reflected light from the effective area corresponding to the line-shaped effective pixels in the entire imaging range of the fundus is selectively guided to the imaging surface, so that the image of the effective area is captured.

The scanning unit synchronously scans the local illumination area and the effective area (local imaging area) on the fundus. The scanning unit may be, for example, an optical scanner shared between the irradiation optical system and the light receiving optical system. In this case, the optical scanner is arranged on the common optical path of the irradiation optical system and the light receiving optical system.

Further, the scanning section may include a first scanning section provided in the irradiation optical system and a second scanning section provided in the light receiving optical system, which is separate from the first scanning section. In this case, in an example of a slit scan type apparatus, a first slit-shaped member (an example of a diaphragm) is arranged on the optical path of the irradiation optical system in order to form a slit-shaped local illumination area. good too. The first scanning section may have a first slit-shaped member and a driving section that moves the first slit-shaped member in a direction intersecting the optical axis. Furthermore, when the second slit-shaped member is used as the harmful light removing section, the second scanning section drives the second slit-shaped member (an example of the diaphragm) and the second slit-shaped member in a direction intersecting the optical axis. You may have a part and a. The driving section of the first scanning section and the driving section of the second scanning section may be separate devices or may be a common device.

Further, in a slit scan type apparatus, when a CMOS is used as a light receiving element, the CMOS may also serve as the second scanning unit. That is, the line exposure by the rolling shutter function may be controlled in synchronization with the first scanning section. In this case, the CMOS, which is the light receiving element, serves both as the harmful light removal section and as the second scanning section. This reduces the number of parts in the optical system.

<Suppression of change in image height due to dioptric correction>
In the scanning optical system as described above, if there is a positional shift between the illumination area and the effective area on the fundus, the amount of received light may decrease, or an image may not be obtained at all. can be considered.

On the other hand, the dioptric correction optical system may include a telecentric optical system. In this telecentric optical system, when the correction amount on the irradiation side and the correction amount on the light receiving side are the same and when they differ from each other, in each of the irradiation optical system and the light receiving optical system, the image is corrected more than the dioptric correction optical system. Maintain the image height in the region on the side. However, in both the irradiation optical system and the light receiving optical system, the side of the subject's eye is referred to as the object side, and the side opposite to the subject's eye across the diopter correction optical system is referred to as the image side. Even if the amount of correction on the irradiation side and the amount of correction on the light receiving side do not match, the telecentric optical system makes it difficult for the positional deviation between the illumination area and the effective area on the fundus to occur. Therefore, the above-described telecentric optical system has the effect of being able to take good fundus images when suppressing the occurrence of artifacts in an apparatus having a scanning-type imaging optical system. However, the telecentricity in the optical system of the embodiment may be imperfect within the allowable accuracy range.

More specifically, the telecentric optical system may have a first telecentric optical system and a second telecentric optical system. The first telecentric optical system maintains the image height in the area closer to the image side than the dioptric correction optical system regardless of changes in the amount of correction on the light receiving side. The second telecentric optical system maintains the ray height of the principal ray of the illumination light on the fundus regardless of changes in the irradiation-side correction amount.

The telecentric optical system is also useful in non-scanning imaging optical systems. That is, the telecentric optical system suppresses the change in the magnification of the fundus image and the change in illumination unevenness due to diopter correction.

<Adjustment of shooting conditions according to dioptric correction amount>
As a result of adjusting the irradiation-side correction amount to a value different from the light-receiving-side correction amount, for example, the following phenomenon may occur. For example, the outer edge of the region irradiated with the illumination light on the fundus may be blurred. Also, the position of the area irradiated with the illumination light may be shifted from the position of the effective area. When these phenomena occur, the amount of received light is more likely to decrease than when the amount of correction on the irradiation side and the amount of correction on the light receiving side match.

On the other hand, in the present embodiment, between the first imaging mode and the second imaging mode, the controller controls at least one of the amount of illumination light irradiated to the fundus, the gain of the light receiving element, and the exposure time. may be switched. More specifically, in the second photographing mode, at least one of the light amount of the illumination light, the gain of the light receiving element, and the exposure time is increased as compared with the first photographing mode. As a result, a fundus image with a wide dynamic range can be obtained even when the amount of correction on the irradiation side and the amount of correction on the light receiving side do not match. Note that the control unit may slow down the scanning speed in order to increase the exposure time. In addition, in an apparatus that continuously captures a plurality of fundus images and adds the plurality of images to capture a single captured image, increasing the number of fundus images used for addition reduces the exposure time. can be substantially increased.

<Refractive power acquisition part>
The refractive power information acquisition unit acquires refractive power information as information on the refractive power of the subject's eye.

For example, the refractive power information acquisition section may be a measurement section. In this case, refractive power information is obtained as a result of measurement of the subject's eye.

At least part of the imaging optical system may be used for the measurement section as the refractive power information acquisition section. For example, the refractive power information acquisition unit may detect the focus state in the light receiving optical system and acquire the refractive power information based on the detection result of the focus state. More specifically, the focus state is detected while the light-receiving side correction amount, which is the diopter correction amount in the light-receiving optical system, is changed, and the value of the light-receiving side correction amount when the best focus state is obtained is the refractive index. It may be acquired as frequency information. However, the refractive power information is not necessarily limited to the light receiving side correction amount. For example, either the drive amount in the driving unit driven to change the light receiving side correction amount (or the irradiation side correction amount), the position information of the optical element displaced by the driving unit, or the like is used as the refraction power information. can be utilized.

The focus state may be detected based on the fundus image acquired via the imaging optical system. In this case, the focus state may be detected as contrast information of the fundus image. Further, the focus state may be detected based on the fundus image in which the index image of the focus index is reflected. A split indicator is known as an example of the focus indicator (see FIG. 2). The split index is projected onto the fundus as two index images separated by a prism. The focus state may be detected based on the positional relationship between the two index images. In this case, the refractive power information acquisition section includes an index projection section that projects the focus index.

Note that the refractive power information acquisition unit is not necessarily limited to the measurement unit. For example, the refractive power information acquisition unit may be configured to receive refractive power information previously measured by a device separate from the fundus imaging device and acquire the refractive power information. In this case, the refractive power information acquisition section may include a control section, a port, and the like. A port is used to connect a separate device, an external storage medium, a user interface, or the like to the ophthalmologic measurement device. Separate devices include, for example, subjective or objective refraction testing devices. Refraction power information may be stored in advance in the external storage medium. The control unit may acquire the information by reading the refractive power information from the storage medium. The user interface may also be utilized to manually enter refractive power information. In this case, the refractive power information may be acquired as an input result by the examiner.

<Adjustment of the difference value between the irradiation-side correction amount and the light-receiving side correction amount in consideration of the pupil diameter>
The positional relationship between the pupil of the eye to be inspected and the light projecting area and the light receiving area in the imaging optical system may be changeable according to the size of the pupil of the eye to be inspected. In the present disclosure, the region where the illumination light is projected on the pupil of the subject's eye is referred to as the "projection region", and similarly the region on the pupil where the fundus reflected light of the illumination light is extracted is referred to as the "light receiving region". .

As an example, the clearance between the light projecting area and the light receiving area may be changeable. By narrowing the clearance, it becomes easier to photograph eyes with small pupils. However, in this case, if the clearance is narrowed, artifacts due to reflected light from the objective lens tend to occur.

As another example, the alignment position in the XY directions (up, down, left, and right) may be changeable. If the eye has a small pupil and vignetting occurs in a part of the light projecting area and the light receiving area, the alignment reference position in the XY directions may be appropriately changed. By appropriately changing the alignment state, the balance of light emission and reception can be improved. However, the range of the diopter correction amount in which artifacts based on the light reflected by the objective lens occur may change depending on the alignment state in the XY directions.

On the other hand, the controller may adjust the difference value between the irradiation-side correction amount and the light-receiving side correction amount according to the size of the pupil of the subject's eye. For example, in the case of the first pupil diameter, it is adjusted to the first difference value, and in the case of the second pupil diameter smaller than the first pupil diameter, the second difference is large with respect to the first difference value value (see FIG. 5). As a result, even if the positional relationship between the pupil of the subject's eye and the light projecting area and the light receiving area in the imaging optical system is changed according to the size of the pupil of the subject's eye, a fundus image with suppressed artifacts can be captured. can be Note that the control unit may control the difference value in conjunction with the control of the positional relationship described above.

When the difference value is adjusted according to the size of the pupil, the fundus imaging device may further include a pupil information acquisition unit that acquires information indicating the size of the pupil (referred to as pupil information). The pupil information acquisition unit may include, for example, an anterior segment imaging optical system that captures an anterior segment image of the subject's eye, and an image processor that acquires pupil information from the anterior segment image.

<Second embodiment>
Next, a second embodiment will be described.

The fundus imaging apparatus according to the second embodiment executes processing for suppressing artifacts due to reflection of the objective lens (hereinafter referred to as artifact suppression processing). In the second embodiment, artifact suppression processing is automatically performed when the refractive power of the subject's eye falls within a predetermined range. On the other hand, if the refractive power is out of range, no artifact suppression processing is performed. As described above, in the second embodiment, the invalid mode in which artifact suppression processing is disabled (that is, no processing is performed) when capturing a fundus image, and the artifact suppression processing is enabled in capturing a fundus image. The photographing mode is switched by the control unit between the effective mode (that is, executing the processing) and the photographing mode based on the refractive power.

As described in the first embodiment, when diopter correction is performed in both the irradiation optical system and the light receiving optical system according to the refractive power, artifacts are more likely to occur as the refractive power is on the minus diopter side. Become. Therefore, in the second embodiment, of the case where the refractive power is included in the first range and the case where the refractive power is included in the second range (negative diopter side with respect to the first range), the former In the latter case, the disabled mode may be set, and in the latter case, the enabled mode may be set. As a result, regardless of the refractive power of the subject's eye, a fundus image in which the occurrence of artifacts is suppressed is obtained. In addition, when imaging an eye to be inspected whose refractive power is relatively on the positive diopter side and artifacts are unlikely to occur, the effect on the fundus image based on artifact suppression processing and the burden on the subject due to imaging, etc. are prevented.

Diopter correction optics for setting the irradiation side correction amount (dioptric correction amount in the irradiation optical system) and the light receiving side correction amount (diopter correction amount in the light receiving optical system) in the first embodiment to a mismatched state System drive processing is an example of various artifact suppression processing. However, the artifact suppression processing in the second embodiment is not necessarily limited to this. For example, in the artifact suppression process, a plurality of fundus images having different artifact positions with respect to the tissue of the eye to be inspected may be captured, and a composite image may be generated by synthesizing the plurality of fundus images (for example, hereinafter 2nd and 6th artifact suppression processing). Also, various operations exemplified in the following description may be employed.

The detailed configuration of the second embodiment will be described below, focusing on the differences from the first embodiment. A fundus imaging apparatus according to the second embodiment has at least an imaging optical system, an image processing section, a refractive power acquisition section, and a control section. For each of these configurations, the items of <control unit>, <image processing unit>, <photographing optical system>, and <refractive power acquisition unit> in the description of the first embodiment can be used as appropriate.

<Second Artifact Suppression Processing>
In the second artifact suppression process, the fundus image is captured at least twice by switching the positional relationship between the imaging optical axis and the visual axis of the subject's eye. Furthermore, a plurality of fundus images obtained by at least two shots are synthesized by the image processing unit. As a result, the device acquires a composite image, which is an artifact-suppressed fundus image (see FIG. 6). In FIGS. 6 to 11, artifacts are denoted by symbol N or symbols N1 and N2. The image processing unit detects an area including an artifact in at least one of the plurality of fundus images (referred to as a first fundus image) as an image area that has the same positional relationship with respect to the fundus tissue as that area, and processes the area in another fundus image. A composite image is generated by interpolating using the image regions. More specifically, a region containing an artifact in at least one of the plurality of fundus images may be replaced with a corresponding image region in another image. Also, a region including artifacts may be complemented by image addition of a plurality of fundus images.

In order to perform the second artifact suppression process, the fundus imaging device may have a position adjuster. The position adjustment unit adjusts the position where the artifact is generated with respect to the fundus tissue in the fundus image by changing the positional relationship between the imaging optical axis and the visual axis of the subject's eye. The position adjustment section may include a fixation optical system. The fixation optical system presents a fixation target to the eye to be examined. The fixation optical system may be capable of switching the presentation position of the fixation target to a plurality of positions with respect to the direction intersecting the imaging optical axis. Further, the position adjusting section may include a driving section that moves the imaging optical system with respect to the subject's eye. For example, the driving unit may change the positional relationship between the imaging optical axis and the visual axis of the subject's eye by rotating the imaging optical system around the anterior segment of the subject's eye. Of course, the position adjustment section may include both the fixation optical system and the drive section.

For more detailed content regarding the second artifact suppression processing, see, for example, Japanese Patent Application Laid-Open No. 2017-184787 filed by the present applicant.

<Third Artifact Suppression Processing>
In the third artifact suppression process, the image processing unit performs background subtraction based on the fundus image and the background image, and as a result, an artifact-suppressed fundus image is generated (see FIG. 7). The background image here is a background image for the fundus image, and includes at least artifacts due to the objective lens. The background image may be an image captured with the front side of the objective lens covered with a lid such as a lens cover.

For more detailed content regarding the third artifact suppression process, see, for example, Japanese Patent Application Laid-Open No. 2017-217076 filed by the present applicant.

<Apparatus Configuration Prerequisite for Fourth and Fifth Artifact Suppression Processing>
Both the fourth and fifth artifact suppression processes are based on the premise that the imaging optical system has the following configuration. That is, the imaging optical system is a slit scan type optical system. For example, the optical system shown in FIG. 2 may be used. The imaging optical system has at least a slit forming section, a scanning section, and a light emitting/receiving separating section. Additionally, the imaging optical system may have a light source, an imaging device, an optical path branching section, and the like.

The slit forming section forms the illumination light in a slit shape on the fundus of the eye to be examined. The slit forming part may be, for example, a slit-shaped translucent part (for example, an opening) arranged in a plane that is conjugate with the fundus.

As shown in FIGS. 2 and 8, the scanning unit scans the slit-shaped illumination light on the fundus in a direction that intersects the slit (more specifically, a direction that intersects the longitudinal direction of the slit). . The scanning unit may scan the illumination light by moving the slit forming unit in a direction intersecting the slit. Examples of this type of scanning unit include mechanical shutters, liquid crystal shutters, optical choppers (see FIG. 12), and drum reels.

The scanning direction of the slit is preferably a direction perpendicular to the slit. However, it may be in an oblique direction with respect to the orthogonal direction of the slit.

Further, the scanning section may be a member that changes the direction of light that has passed through the slit forming section. For example, various optical scanners such as galvanometer scanners may be used as the scanning unit. A scanning unit that scans by rotating light, such as a galvanometer scanner, may be placed at a position that is conjugate with the pupil of the subject's eye.

The imaging optical system may further have an optical path coupling section and an objective lens.

The optical path coupling unit couples and separates the projection optical path of the illumination light and the reception optical path of the fundus reflected light. The objective lens is arranged on the common optical path of the light-projecting optical path and the light-receiving optical path formed by the optical path coupling section. At this time, it is desirable that the photographing optical axis and the optical axis of the objective lens match.

Various beamsplitters can be used as optical path couplers. In this case, the optical path coupling portion may be a perforated mirror, a simple mirror, a half mirror, or another beam splitter.

The light projecting/receiving separation unit separates a light projecting area and a light receiving area on the pupil of the subject's eye.

Specifically, as shown in FIGS. 2 and 9, the light projecting/receiving separation unit forms light projecting areas at two positions separated from each other in the scanning direction of the illumination light. The two light projection areas may be formed so as to sandwich the imaging optical axis. In the first embodiment, the light projecting/receiving separation section may form at least two light projecting regions, and may form three or more light projecting regions. The illumination light that has passed through each light projection area irradiates the same slit-shaped area on the fundus. Then, the slit-shaped area is scanned as the scanning unit is driven.

As shown in FIG. 9, the light projecting/receiving separation section forms a light receiving area sandwiched between two light projecting areas. That is, the regions are arranged in a row in the order of one light projection region, light reception region, and other light projection region. Also, the light receiving area may be formed on the imaging optical axis. The light projecting area and the light receiving area may be arranged so as not to overlap each other. In this case, part of the illumination light is reflected and scattered by the cornea and the intermediate translucent body, thereby reducing the occurrence of flare in the fundus image.

The light projecting/receiving separation section may include a plurality of members arranged respectively in the light projecting optical path and the light receiving optical path of the illumination light.

A part of the light projecting/receiving separation unit sets the irradiation position of the illumination light at, for example, at least two positions separated from each other in the scanning direction of the illumination light on the pupil conjugate plane in the light projection optical path of the illumination light. may be In this case, the illumination position may be set by arranging illumination light sources at two positions on the pupil conjugate plane. Alternatively, the irradiation position may be set by arranging apertures through which the illumination light from the light source passes at two positions on the pupil conjugate plane as apparent illumination light sources.

In other words, the light projecting/receiving separation unit includes at least two illumination light sources or two apparent illumination light sources arranged at positions conjugated to the pupil of the subject's eye and at different positions in the scanning direction. There may be. Thereby, the light projection areas are formed at two positions separated from each other with respect to the scanning direction of the illumination light. More preferably, the two illumination sources or the two apparent illumination sources may be arranged symmetrically with respect to the imaging optical axis. Thereby, two light projection areas can be formed symmetrically with respect to the photographing optical axis. The light projection state from the two illumination light sources or the two apparent illumination light sources may be controllable for each light source by a control section to be described later. As a result of controlling the light projection state for each light source, whether or not to pass the illumination light is individually set for each light projection area. Of course, the number of illumination light sources included in the light projecting/receiving separation section or the apparent number of illumination light sources may be three or more.

As for the light projection state, there are at least two types of states: a state in which the illumination light from the illumination light source or the apparent illumination light source reaches the eye to be inspected, and a state in which the illumination light does not reach the eye. The switching of the light projection state may be realized by lighting control of the light source. Alternatively, the light projection state may be switched using a shutter that selectively blocks a light beam directed from the illumination light source or an apparent illumination light source toward the eye to be inspected.

A part of the light projecting/receiving separation unit passes the fundus reflected light from the light receiving area sandwiched between the two light projecting areas on the pupil conjugate plane in the light receiving optical path of the illumination light to the imaging plane side. , other light may be prevented from passing through to the imaging surface side. For example, the light projecting/receiving separation unit may include a light shielding member that allows the fundus reflected light from the light receiving region to pass through to the imaging surface side and blocks other light. The light shielding member may be arranged, for example, on the pupil conjugate plane in the light receiving optical path. For example, when a diaphragm having an aperture centered on the photographing optical axis is provided as the light shielding member, the light receiving area is formed by the aperture image of the diaphragm.

When a light shielding member is included in the light emitting/receiving separation section, the light shielding member may be shared with the optical path coupling section described above, or may be a separate member.

<Fourth Artifact Suppression Processing>
In the apparatus configuration described above, the controller may individually set whether or not the illumination light is allowed to pass through the two light projection areas on the pupil of the subject's eye. In this case, the control unit may capture the fundus image based on the illumination light selectively projected from one (either) of the two light projection areas.

By the way, a reflected image (bright point image, a type of artifact) may be generated at a position near the imaging optical axis in the fundus image due to reflection of the illumination light at the center of the lens surface of the objective lens. Since the projected light area is away from the imaging optical axis, the reflected image tends to appear at a position slightly displaced from the imaging optical axis in the fundus image. As an example, FIG. 10A shows a fundus image captured by simultaneously projecting illumination light from both of the two projection areas. As shown in FIG. 10A, reflected images (indicated by symbols N1 and N2) can be generated at two locations across the imaging optical axis in the image center of the fundus image corresponding to the two light projection areas. The two reflected images appear side by side in the scanning direction (in other words, at different positions in the scanning direction).

On the other hand, in the present embodiment, the illumination light is selectively projected onto the fundus from one of the two light projection areas, and the fundus image is captured. This halves the number of locations in the objective lens where the reflected image is generated compared to the above case. As a result, as shown in FIG. 10B, the reflected image in the fundus image can be halved. In this way, it is advantageous to reduce artifacts by selectively projecting illumination light from one of the two light projection regions on the pupil of the subject's eye to the fundus to capture the fundus image. be.

<Fifth Artifact Suppression Processing>
After capturing a first fundus image by selectively projecting illumination light from one of the two light projection areas onto the fundus, the controller further projects the illumination light from the other light projection area. The second fundus image may be captured by switching to , and selectively projecting illumination light from the other. By taking such two shots, two fundus images are obtained in which the appearance positions of artifacts such as reflected images by the objective lens differ from each other according to the light projection area used for the shots. The imaging may be performed without changing the positional relationship between the subject's eye and the imaging optical system between the first imaging and the second imaging. Moreover, it is desirable that the second fundus image is taken continuously and automatically after the first fundus image is taken.

In the present embodiment, there is no need to change the positional relationship between the subject's eye and the imaging optical system when taking two fundus images. It is possible to switch the projection area on the pupil of the eye to be inspected in a short time. Therefore, two fundus images can be captured in a short time. As a result, even if the first fundus image and the second fundus image are continuously captured, the burden on the subject is reduced. In addition, even if the illumination light is visible light, the second shot is taken immediately after the first shot, so the miosis caused by the first shot will appear in the second shot. You can control the impact.

Here, an example of the effect of miosis is that illumination light and fundus reflected light are vignetted by the iris, resulting in a darkened fundus image. The vignetting effect (brightness change) between the image center and the image periphery is not necessarily uniform. For example, the periphery of an image may be more susceptible to vignetting as the shooting angle of view increases.

In the fifth artifact suppression process, these two fundus images may be combined to generate one fundus image (hereinafter referred to as a "composite image"). Synthesis processing is executed by the image processing unit. In this embodiment, synthesis processing is performed in order to obtain an image in which the effects of artifacts are suppressed. There are various possible synthesis methods, as exemplified below.

For example, a composite image may be generated by replacing a region containing an artifact in one of the two fundus images with a part of the other fundus image corresponding to that region (see FIG. 11). ). At this time, replacement may be performed in units of scanning lines. For example, when the aforementioned reflected image occurs as an artifact, a composite image may be generated by replacing the reflected image occurring in the image center of one fundus image with the corresponding area in the other fundus image.

Alternatively, a composite image may be generated as an averaged image of two fundus images. In this case, the averaging process may be performed by giving different addition ratios between the reflected image and the other areas.

Note that the area where the reflected image is generated is a substantially constant area based on the photographing optical axis, although there are some fluctuations depending on the dioptric power. Therefore, in the two fundus images, the area to be synthesized with the other image in the synthesizing process may be determined in advance. However, the invention is not necessarily limited to this, and a reflection image detection process may be performed on the fundus image, and regions to be combined may be individually set based on the result of the detection process. Also, the region to be combined may be set according to the diopter.

Note that the control unit captures the first fundus image based on scanning only a part of the scanning range corresponding to the composite image, switches the light projection area, and then captures two images based on the scanning of the remaining part. A composite image may be generated by taking a second fundus image and combining (collage) the fundus images. In this case, it is preferable that the scanning range is divided into two around the imaging optical axis, and fundus images are captured in each of the two divided scanning ranges. Note that in this case, the synthesizing process is not necessarily limited to image processing. For example, a composite image can be formed on the imaging surface by switching the projection area for projecting the illumination light at the timing when the illumination light arrives at the division position of the scanning range.

In this case, between the two fundus images, it is preferable that the relationship between the scanning range on the fundus and the projection area onto which the illumination light is projected intersects between the two fundus images. For example, when two light projecting regions are arranged side by side in the vertical direction and illumination light is scanned vertically on the fundus, when the illumination light is passed from the upper light projecting region, the lower half of the fundus When the first fundus image is captured based on the scanning and the illumination light is passed through the lower projection area, the second fundus image is captured based on the scanning of the upper half of the fundus. A composite image may be generated. In this case, the reflected image of the objective lens and the images obtained by photographing portions in which artifacts such as flare are less likely to be included are combined with each other in relation to each light projection area. Therefore, it is possible to obtain a composite image in which artifacts are suppressed.

Instead of this synthesizing process, the following shooting control may be executed. That is, the control unit may switch the light projection area at the timing when the illumination light that scans the fundus during imaging reaches the boundary position of the two divisions. A synthesized image in which a reflected image is suppressed is generated without requiring synthesis processing.

<Sixth Artifact Suppression Processing>
In the sixth artifact suppression process, the fundus image is captured twice (at least twice) without changing the positional relationship between the imaging optical axis and the visual axis of the subject's eye. Between the two shots, the control section switches the shooting conditions other than the positional relationship. As a result, the first fundus image in which artifacts are suppressed and the second fundus image in which image quality is prioritized over the first fundus image are photographed, and the area including the artifact in the second fundus image is captured. , synthesize corresponding regions in the first fundus image. As a result, the device acquires a composite image that is an artifact-suppressed fundus image.

In the sixth artifact suppression processing, since the positional relationship between the imaging optical axis and the visual axis of the subject's eye is not changed between the two imaging operations, two imaging operations can be performed in a shorter time than the second artifact suppression processing. A photograph can be taken to obtain a composite image.

Various conditions that provide a trade-off between the image quality and the difficulty of generating artifacts can be imaging conditions that are changed between two imagings.

For example, between two shots, the control unit may change the shooting conditions regarding the diopter correction amount. In this case, the first fundus image may be, for example, a fundus image obtained by performing the artifact suppression processing in the first embodiment described above. That is, the fundus image may be photographed by adjusting the irradiation-side correction amount to a value different from the light-receiving side correction amount. In this case, the second fundus image may be a fundus image photographed in a state in which the irradiation-side correction amount and the light-receiving-side correction amount match.

Also, for example, between two shots, the control unit may change the condition regarding the state of separation between the fundus reflected light and the harmful light. In this case, the first fundus image can be captured under imaging conditions such that the luminance is lower than that of the second fundus image.

For example, when capturing the first fundus image, the aperture of the diaphragm disposed in at least one of the light projecting optical system and the light receiving optical system is reduced compared to when capturing the second fundus image. good too. For example, in the above-described slit scan type optical system, the size of the translucent portion (for example, the aperture) in the slit forming portion is set to may be reduced compared to In addition, when the first fundus image is captured, the passage area of the reflected light from the fundus in a harmful light removing unit (for example, a diaphragm) provided in the light receiving optical system is larger than that when capturing the second fundus image. may be restricted by As a result, the harmful light reflected by the objective lens or the like is preferably separated from the fundus reflected light guided onto the imaging plane. As a result, it becomes easier to acquire a fundus image in which artifacts are suppressed.

In the case of a slit scan type optical system, one or both of the slit forming section and the harmful light removing section may be variable slits. In the case of a variable slit, the width of the illumination area, effective area (imaging area), or both can be switched between a first width and a second width wider than the first width. In this case, one or both of the slit forming portion and the harmful light removing portion have at least two types of slit openings, a first slit opening corresponding to the first width and a second slit opening corresponding to the second width. may have

In this case, as shown in FIG. 13, the fundus imaging device may have an optical chopper with a rotating body (for example, a wheel) as a scanning unit. In the optical chopper, a rotating body in which a plurality of slit openings are arranged side by side on one circumference serves as one or both of the slit forming section and the harmful light removing section. In the optical chopper, the rotating body is rotationally driven. Thereby, a plurality of slit apertures are continuously traversed with respect to the optical path of illumination light or return light. The shape of the rotating body may be, for example, a disk shape (wheel shape) as shown in FIG. 13, or a cylindrical shape. A plurality of slits are formed in the cylindrical side surface of the cylindrical rotating body. Note that the rotating body may be driven at a constant speed.

In the example of FIG. 13, the rotating body includes a first area in which one or more first slit openings corresponding to the first width are continuously arranged, and second slit openings corresponding to the second width. and a second area in which one or two or more are arranged in succession. In this case, the controller controls the illumination area or effective area (imaging area) on the fundus between the first period during which the first area passes through the optical path and the second period during which the second area passes through the optical path. Width is switched. The control unit obtains a fundus image obtained in the first period as a first fundus image, obtains a fundus image obtained in the second period as a second fundus image, and generates a composite image of the two. good too.

Note that when the illumination light is visible light, it is preferable to first capture the second fundus image in which image quality is prioritized among the two fundus images, and then capture the first fundus image. . Therefore, the control unit may execute a continuous photographing operation (continuous photographing process) of photographing two fundus images at predetermined intervals in the order of the second fundus image and the first fundus image. It is preferable that the predetermined interval is sufficiently short from the time (about several tens of seconds) from the time when the image is taken with visible light until the miosis disappears.

When two images of the fundus oculi are captured in a short period of time using visible light, miosis occurs, and in images captured later, vignetting of the illumination light at the pupil tends to darken the periphery. On the other hand, by first capturing the second fundus image in which image quality is prioritized and then capturing the first fundus image, it is easy to obtain a good fundus image up to the periphery in the composite image.

If the scanning unit is an optical chopper, the device may further include a sensor that detects the rotational position of the rotating body. Based on the signal from the sensor, the exposure of the imaging device and sweeping out of the image may be controlled.

<Third Embodiment>
Next, a third embodiment will be described. The fundus imaging apparatus according to the third embodiment (see FIG. 14) captures a fundus image by scanning the fundus with a slit of illumination light. The apparatus according to the third embodiment captures a fundus image with the diaphragm placed at a position different from the fundus conjugate position. Arranging the diaphragm at a position different from the fundus conjugate position during imaging can suppress artifacts caused by reflection on the objective lens. Note that the fundus imaging apparatus according to the third embodiment may include some of the multiple embodiments described above as the first embodiment.

A fundus imaging apparatus according to the third embodiment has at least an imaging optical system and a dioptric correction optical system. Additionally, the fundus imaging device may have a control unit.

An imaging optical system according to the third embodiment includes an irradiation optical system, a light receiving optical system, and a scanning section. The irradiation optical system irradiates the fundus of the subject's eye with slit-shaped illumination light through the objective lens. The light receiving optical system shares the objective lens with the irradiation optical system. The light-receiving optical system further forms an image of the fundus on the imaging plane based on the fundus-reflected light of the illumination light.

The scanning unit according to the third embodiment is used to displace one or both of the local illumination area and the local imaging area, which are part of the imaging range of the fundus. The scanning unit according to the third embodiment may have at least a slit and a driving unit (driver). Alternatively, the scanning unit may be a device that scans illumination light previously formed in a slit shape. The diaphragm may be arranged in either one of the irradiation optical system and the light receiving optical system, or may be arranged in both. The shape of the aperture in the diaphragm may be, for example, slit-like (see the first and second embodiments), circular, or other shapes. Further, when a device that scans illumination light that is formed in a slit shape in advance is used as the scanning unit, the diaphragm may be statically arranged with respect to the optical system.

The diopter correction optical system corrects diopter in the imaging optical system.

In the third embodiment, in the apparatus configuration as described above, a fundus image is captured with the diaphragm arranged at a position different from the fundus conjugate position. However, the diaphragm may be for removing stray light from the anterior segment. In other words, the diaphragm has a non-conjugated positional relationship with both the cornea and the lens. In addition, it is preferable to arrange the lens in the vicinity of the fundus conjugate position within a range where the effect of suppressing reflection from the objective lens can be enjoyed.

At this time, the diaphragm may be arranged in advance, for example, at a position away from either the imaging plane or its conjugate position. At this time, the diaphragm is preferably arranged on the plus diopter side with respect to the conjugate position of the imaging plane. By arranging the diaphragm in advance at a position different from the imaging plane and its conjugate position, the position of the diaphragm can be kept away from the condensing position of the reflected light on the objective lens, and artifacts can be suppressed.

In addition, when the diaphragm is placed away from the imaging plane and its conjugate position, the diopter correction in both the irradiation optical system and the light receiving optical system should be equal to the refractive power of the subject's eye. Once done, a fundus image may be taken. In this case, the dioptric correction optical system does not necessarily have an irradiation side correction amount (the diopter correction amount in the irradiation optical system) and a light receiving side dioptric correction amount (the dioptric correction amount in the light receiving optical system), respectively. It does not have to be independently adjustable. Therefore, the device configuration can be easily simplified.

On the other hand, the fundus imaging device according to the third embodiment may have dioptric correction optics similar to those of the first embodiment. In this case, the diopter correction optical system can independently adjust the irradiation side correction amount, which is the dioptric correction amount in the irradiation optical system, and the light receiving side correction amount, which is the dioptric correction amount in the light receiving optical system. good too. The control unit may control the diopter correction optical system and set the irradiation-side correction amount and the light-receiving side correction amount to different values when the fundus image is captured. At this time, the light-receiving side correction amount may be a value corresponding to the refractive power of the eye to be examined, and the irradiation side correction amount may be a value different from the value corresponding to the refractive power of the eye to be examined.

"Example"
Next, an example of the fundus imaging apparatus according to the first to third embodiments will be described with reference to FIGS. 1 to 4, 12, and 15. FIG.

A fundus photographing device 1 (hereinafter simply referred to as “photographing device 1”) forms illumination light in a slit shape on the fundus of an eye to be examined, scans the slit-shaped region on the fundus, and emits illumination light. A front image of the fundus is captured by receiving the reflected light of the fundus.

<Appearance of device>
Referring to FIG. 1, the external configuration of the photographing device 1 will be described. The imaging device 1 has an imaging unit 3 . The photographing unit 3 mainly includes an optical system shown in FIG. The photographing apparatus 1 has a base 7 , a drive section 8 , a face support unit 9 , and a face photographing camera 110 , and uses these to adjust the positional relationship between the subject's eye E and the photographing unit 3 .

The drive unit 8 can move in the left-right direction (X direction) and front-rear direction (Z direction, in other words, working distance direction) with respect to the base 7 . Further, the driving section 8 moves the photographing unit 3 on the driving section 8 with respect to the subject's eye E in three-dimensional directions. The driving section 8 has an actuator for moving the driving section 8 or the photographing unit 3 in each predetermined movable direction, and is driven based on a control signal from the control section 80 . A face support unit 9 supports the subject's face. A face support unit 9 is fixed to the base 7 .

The face photographing camera 110 is fixed to the housing 6 so that the positional relationship with respect to the photographing unit 3 is constant. A face photographing camera 110 photographs the subject's face. The control unit 100 specifies the position of the subject's eye E from the photographed face image, and drives and controls the driving section 8 to align the photographing unit 3 with the specified position of the subject's eye E.

In addition, the photographing device 1 further has a monitor 120 . The monitor 120 displays a fundus observation image, a photographed fundus image, an anterior segment observation image, and the like.

<Optical System of Example>
Next, referring to FIG. 2, the optical system of the photographing device 1 will be described. The photographing device 1 has a photographing optical system (fundus photographing optical system) 10 and an anterior segment observation optical system 40 . These optical systems are provided in the photographing unit 3 .

In FIG. 2, positions conjugated to the pupil of the subject's eye are indicated by "Δ" on the photographing optical axis, and positions conjugate to the fundus are indicated by "x" on the photographing optical axis.

The imaging optical system 10 has an irradiation optical system 10a and a light receiving optical system 10b. In the embodiment, the illumination optical system 10a has a light source unit 11, a lens 13, a slit member 15a, lenses 17a and 17, a mirror 18, a perforated mirror 20, and an objective lens 22. The light receiving optical system 10b has an objective lens 22, a perforated mirror 20, lenses 25a and 25b, a slit-shaped member 15b, and an imaging device . Note that the perforated mirror 20 is an optical path coupling portion that couples the optical paths of the irradiation optical system 10a and the light receiving optical system 10b. The perforated mirror 20 reflects the illumination light from the light source toward the eye to be inspected E, and allows a part of the fundus reflected light from the eye to be inspected E that has passed through the aperture to pass through to the imaging element side. Various beam splitters other than the apertured mirror 20 can be used. For example, instead of the perforated mirror 20, a mirror in which the perforated mirror 20, the transmissive portion and the reflective portion are reversed may be used as the optical path coupling portion. However, in this case, the independent optical path of the light receiving optical system 10b is placed on the reflection side of the mirror, and the independent optical path of the irradiation optical system 10a is placed on the transmission side of the mirror. Also, the perforated mirror and its alternative mirror can be further replaced by a combination of a half mirror and a light blocking section.

In this embodiment, the light source unit 11 has multiple types of light sources with different wavelength bands. For example, the light source unit 11 has visible light sources 11a and 11b and infrared light sources 11c and 11d. Thus, the light source unit 11 of this embodiment is provided with two light sources for each wavelength. Two light sources with the same wavelength are placed apart from the imaging optical axis L on the pupil conjugate plane. The two light sources are arranged along the X direction, which is the scanning direction in FIG. As shown in FIG. 2, the outer peripheral shapes of the two light sources may be rectangular shapes in which the direction intersecting the scanning direction is longer than the scanning direction.

Light from the two light sources passes through the lens 13 and irradiates the slit-shaped member 15 . In this embodiment, the slit-like member 15a has a translucent portion (aperture) elongated along the Y direction. As a result, the illumination light is formed in a slit shape on the fundus conjugate plane (the area illuminated in a slit shape on the fundus is illustrated as B).

In FIG. 2, the slit-shaped member 15a is displaced by the driving section 15c so that the translucent section crosses the photographing optical axis L in the X direction. Thereby, the scanning of the illumination light in this embodiment is realized. In this embodiment, scanning is also performed by the slit member 15b on the light receiving system side. In this embodiment, the slit-shaped members 15a and 15b on the light-projecting side and the light-receiving side are driven in conjunction with one driving section (actuator). In this embodiment, the scanning section is realized by the slit-shaped members 15a and 15b and the driving section (not shown).

In the irradiation optical system 10a, the image of each light source is relayed by the optical system from the lens 13 to the objective lens 22 and formed on the pupil conjugate plane. That is, images of the two light sources are formed at positions separated in the scanning direction on the pupil conjugate plane. In this way, in this embodiment, the two projection areas P1 and P2 on the pupil conjugate plane are formed as images of the two light sources.

Also, the slit-shaped light that has passed through the slit-shaped member 15a is relayed by the optical system from the lens 17a to the objective lens 22 and forms an image on the fundus Er. Thereby, the illumination light is formed in a slit shape on the fundus Er. The illumination light is reflected on the fundus Er and extracted from the pupil Ep.

Here, since the aperture of the perforated mirror 20 is conjugate with the pupil of the eye to be inspected, the fundus reflected light used for photographing the fundus image passes through the image of the aperture of the perforated mirror (pupil image) on the pupil of the eye to be inspected. limited to some Thus, the image of the aperture on the pupil of the subject's eye is the light receiving region R in this embodiment. The light receiving region R is formed between two light projecting regions P1 and P2 (images of two light sources). Further, as a result of appropriately setting the imaging magnification of each image, the diameter of the aperture, and the arrangement interval of the two light sources, the light receiving region R and the two light projecting regions P1 and P2 are arranged so as not to overlap each other on the pupil. formed in As a result, the occurrence of flare is favorably reduced.

The fundus reflected light that has passed through the apertures of the objective lens 22 and the perforated mirror 20 forms an image of the slit-like region of the fundus Er at the fundus conjugate position via the lenses 25a and 25b. At this time, harmful light is removed by arranging the translucent portion of the slit-shaped member 15b at the image forming position.

The imaging device 28 is arranged at a fundus conjugate position. In this embodiment, a relay system 27 is provided between the slit-shaped member 15b and the imaging device 28, whereby both the slit-shaped member 15b and the imaging device 28 are arranged at the fundus conjugate position. As a result, both harmful light rejection and imaging are performed well. Alternatively, the relay system 27 between the imaging element 28 and the slit member 15b may be omitted and the two may be arranged close to each other. In this embodiment, a device having a two-dimensional light receiving area is used as the imaging element 28 . For example, it may be CMOS, two-dimensional CCD, or the like. An image of the slit-shaped region of the fundus Er formed on the light-transmitting portion of the slit-shaped member 15b is projected onto the imaging device 28 . The imaging device 28 has sensitivity to both infrared light and visible light.

In this embodiment, as the slit-shaped illumination light scans the fundus Er, images (slit-shaped images) of scanning positions on the fundus Er are sequentially projected for each scanning line of the imaging element 28 . In this manner, the entire image of the scanning range is projected onto the imaging device in a time division manner. As a result, a front image of the fundus Er is captured as an entire image of the scanning range.

In the embodiments, the scanning unit in the light receiving system is a device that mechanically scans the slit, but it is not necessarily limited to this. For example, the scanning unit on the light receiving optical system side may be a device that electronically scans the slit. As an example, if the imaging device 28 is a CMOS, slit scanning may be realized by the CMOS rolling shutter function. In this case, by displacing the exposed area on the imaging surface in synchronization with the scanning unit in the light projecting system, it is possible to remove harmful light while efficiently photographing. A liquid crystal shutter or the like can also be used as a scanning unit that electronically scans the slit.

The imaging optical system 10 has a dioptric correction section. In this embodiment, the independent optical path of the irradiation optical system 10a and the independent optical path of the light receiving optical system 10b are each provided with a dioptric correction unit (dioptric correction optical systems 17 and 25). Hereinafter, for convenience, the dioptric correction optical system on the irradiation side will be referred to as the dioptric correction optical system 17 on the irradiation side, and the dioptric correction optical system on the light receiving side will be referred to as the dioptric correction optical system 25 on the light receiving side. The irradiation-side diopter correction optical system 17 of this embodiment includes lenses 17a, 17b, and a driving section 17c (see FIG. 3). The light-receiving side dioptric correction optical system 25 of this embodiment includes a lens 25a, a lens 25b, and a driving section 25c (see FIG. 3). In the dioptric correction optical system 17 on the irradiation side, the distance between the lenses 17a and 17b is changed, and in the dioptric correction optical system 25 on the reception side, the distance between the lenses 25a and 25b is changed. Accordingly, diopter correction is performed in each of the irradiation optical system 10a and the light receiving optical system 10b.

The drive unit 17c of the irradiation optical system 10a and the drive unit 25c of the light receiving optical system 10b can be driven independently. As a result, in this embodiment, as shown in FIG. 4B, the irradiation-side correction amount, which is the diopter correction amount in the irradiation optical system 10a, and the light-receiving-side correction amount, which is the dioptric correction amount in the light receiving optical system 10b, are Each can be set independently.

In this embodiment, each of the irradiation side dioptric correction optical system 17 and the light receiving side dioptric correction optical system 25 includes a telecentric optical system. Each telecentric optical system maintains the image height in the image-side area even if the diopter correction amount changes. Thereby, the positional relationship between the slit aperture of the irradiation optical system and the slit aperture of the light receiving optical system on the fundus can be kept constant regardless of the balance between the irradiation side correction amount and the light receiving side correction amount. Therefore, the slit aperture of the irradiation optical system and the slit aperture of the light receiving optical system on the fundus can always be matched regardless of the balance between the irradiation side correction amount and the light receiving side correction amount. Also, it is possible to suppress the change in the image size according to the change in the diopter correction amount.

As shown in FIG. 2, the imaging optical system 10 further has a split index projection optical system 50 as an example of the focus index projection optical system. A split index projection optical system 50 projects two split indices onto the fundus. A split index is used to detect the focus state. Further, in this embodiment, the refractive power of the subject's eye E is acquired from the detection result of the focus state.

The split target projection optical system 50 may have at least a light source 51 (infrared light source), a target plate 52, and a deviation prism 53, for example. In this embodiment, the index plate 52 is arranged at a position corresponding to the imaging plane in the light receiving optical system 50 . Similarly, the slit-shaped members 15a and 15b are also arranged at corresponding positions. Specifically, when the diopter correction amount on the irradiation side and the light receiving side is 0D, the optotype plate 52 is arranged at a position substantially conjugate with the fundus of the emmetropic eye (0D eye). The deflection prism 53 is arranged closer to the index plate 52 on the subject's eye side than the index plate 52 .

The indicator plate 52 is formed using, for example, slit light as an indicator. A deflection prism 53 splits the index light beam passing through the optotype plate 52 to form a split index. The separated split index is projected onto the fundus of the subject's eye via the irradiation-side dioptric correction optical system 17 and the objective lens 22 . Therefore, the split index is reflected in the fundus image (for example, the fundus observation image).

When the index plate 52 is displaced from the fundus conjugate position, the two split indices are separated on the fundus, and when the index plate 52 is placed at the fundus conjugate position, the two split indices are aligned. The conjugate relationship is adjusted by the irradiation-side dioptric correction optical system 17 arranged between the deviation prism 53 and the subject's eye Er. Therefore, in this embodiment, defocusing is performed while matching the diopter correction amount on the irradiation side and the dioptric correction amount on the light receiving side. At this time, the separation state of the split indicator indicates the focus state. By adjusting the dioptric correction amounts on the irradiation side and the light receiving side so that the two split indices match each other, the imaging surface and the slit-shaped members 15a and 15b each have a conjugate positional relationship with the fundus. Become.

The refractive power of the subject's eye E can be derived from the diopter correction amount when each of the imaging surface and the slit-shaped members 15a and 15b has a conjugate positional relationship with the fundus. Therefore, this embodiment may further include an encoder (not shown) that reads either the distance between the lenses 17a and 17b or the distance between the lenses 25a and 25b. The refractive power of the subject's eye E may be obtained based on the signal from .

Note that the scanning unit may be an optical chopper as shown in FIG. 12, for example. The optical chopper has a wheel with multiple slits on its outer circumference, and by rotating the wheel, the slits can be scanned at high speed.

Here, in FIG. 2, the light source unit 11 to the mirror 18 of the irradiation optical system 10a and the perforated mirror 20 to the imaging device 28 of the light receiving optical system 10b are arranged in parallel in the X direction. By rotating the directions of the aperture mirror 20 and the mirror 18 by 90° from the illustrated state and arranging them in parallel in the Y direction, the optical chopper can be applied as a scanning unit. In this case, as shown in FIG. 12, by crossing the optical axis of the irradiation optical system 10a and the optical axis of the light receiving optical system 10b at two points, the upper end and the lower end of the wheel, respectively, a single optical chopper can be used. , the scanning of the light projecting system and the light receiving system can be easily synchronized.

<Anterior segment observation optical system>
Next, the anterior segment observation optical system 40 will be described. The anterior segment observation optical system 40 shares the objective lens 22 and the dichroic mirror 43 with the imaging optical system 10 . The anterior segment observation optical system 40 further includes a light source 41, a half mirror 45, an imaging device 47, and the like. The imaging device 47 is a two-dimensional imaging device, and is arranged at a position optically conjugate with the pupil Ep, for example. The anterior segment observation optical system 40 illuminates the anterior segment with infrared light and captures a front image of the anterior segment.

Note that the anterior segment observation optical system 40 shown in FIG. 2 is merely an example, and the anterior segment may be imaged through an optical path independent of other optical systems.

<Control system of the embodiment>
Next, referring to FIG. 3, the control system of the imaging device 1 will be described. In this embodiment, the control unit 100 controls each unit of the photographing apparatus 1 . Further, for the sake of convenience, it is assumed that image processing of various images obtained by the photographing device 1 is also performed by the control unit 100 . In other words, in this embodiment, the control section 100 also serves as an image processing section.

The control unit 100 is a processing device (processor) having an electronic circuit that performs control processing of each unit and arithmetic processing. The control unit 100 is implemented by a CPU (Central Processing Unit), a memory, and the like. The control unit 100 is electrically connected to the storage unit 101 via a bus or the like.

The storage unit 101 stores various control programs, fixed data, and the like. Temporary data and the like may be stored in the storage unit 101 .

Images captured by the imaging device 1 may be stored in the storage unit 101 . However, the captured image is not necessarily limited to this, and the captured image may be stored in an external storage device (for example, a storage device connected to the control unit 100 via LAN and WAN).

Further, the control unit 100 includes the driving unit 8, the light sources 11a to 11d, the driving unit 15c, the driving unit 17c, the driving unit 25c, the imaging element 28, the light source 41, the imaging element 47, the light source 51, the input interface 110, the monitor 120, and the like. are electrically connected.

Further, the control unit 100 controls each of the above members based on operation signals output from the input interface 110 (operation input unit). The input interface 110 is an operation input unit that receives operations of the examiner. For example, it may be a mouse and keyboard.

<Description of operation of the embodiment>
Next, the shooting operation will be described based on the flowchart of FIG.

The photographing device 1 may automatically start the photographing operation when the subject's face is placed on the face support section 9 and included in the photographing range of the face detection camera 110 .

First, photographing by the face detection camera 110 and the anterior segment observation optical system 40 is performed in parallel (S1), and alignment adjustment is performed using the photographing results of both (S2).

Specifically, the control unit 100 detects the position of one of the left and right eyes included in the face image, and drives the driving unit 8 based on the position information. Thereby, the position of the photographing unit 4 is adjusted to a position where the anterior segment can be observed.

Next, an alignment reference position is set based on the front image of the anterior segment, and alignment is guided to the set alignment reference position. In this embodiment, the control unit 100 adjusts the positional relationship between the subject's eye E and the imaging unit 3 based on the front image of the anterior segment. In this embodiment, the control unit 100 controls the position where the center of the pupil in the observed image of the anterior eye and the center of the image (in this embodiment, the position of the imaging optical axis L) substantially match based on the signal from the imaging element 47. A first reference position targeting relationship is established. Then, an alignment deviation from the first reference position is detected, and the photographing unit 4 is moved up, down, left and right in a direction in which the alignment deviation is eliminated. At this time, for example, misalignment with the first reference position may be detected based on the amount of misalignment between the center of the pupil on the anterior segment observation image and the imaging optical axis. Further, if the fundus imaging apparatus 1 has, for example, an alignment projection optical system that projects an alignment index onto the corneal vertex, misalignment may be detected based on the amount of deviation between the alignment index and the imaging optical axis. .

Further, the control section 100 moves the photographing unit 4 in the front-rear direction so that the pupil Ep is focused on the pupil Ep. Thereby, the distance from the device to the eye to be examined is adjusted to a predetermined working distance.

As described above, in this embodiment, as a result of the alignment adjustment in S2, the positional relationship between the subject's eye and the imaging unit 4 is such that the center of the light-receiving region R on the pupil of the subject's eye (that is, the imaging optical axis) is the pupil center. (the first reference position in this embodiment).

After the first imaging mode is set, the control unit 100 starts capturing and displaying the fundus observation image (S3). Specifically, the control unit 100 turns on the light sources 11c and 11d at the same time and starts driving the driving unit 15c so that a predetermined range on the fundus Er is repeatedly scanned with the slit-shaped illumination light. Based on the signal output from the imaging device 28, a fundus image captured substantially in real time is generated as the fundus observation image as needed for each predetermined number of scans (at least once). The control unit 100 may display the fundus observation image on the monitor 120 as a substantially real-time moving image.

Next, based on the fundus observation image, the focus states of the irradiation optical system and the light receiving optical system are adjusted (S4). In this embodiment, after the alignment is completed, the dioptric correction optical system is driven to adjust the focus. At this time, in this embodiment, both the irradiation side dioptric correction optical system 17 and the light receiving side dioptric correction optical system 25 are driven.

In the focus adjustment process, the control unit 100 first turns on the light source 51 to start projecting the split index onto the fundus. The control unit 100 performs defocusing by changing the correction amount while matching the diopter correction amount on the irradiation side and the dioptric correction amount on the light receiving side. In addition, the control unit 100 detects the separation state of the split index from the fundus observation image each time the correction amount changes, and adjusts the irradiation-side dioptric correction amount and the light-receiving side dioptric correction amount until the split indices match. adjust. As a result of such adjustment, each of the imaging surface and the slit-shaped members 15a and 15b has a conjugate positional relationship with the fundus.

Also, in this embodiment, the diopter correction amount when the split indices match is acquired by the control unit 100 as refractive power information (S5).

Next, the control unit 100 sets the imaging mode based on the refractive power information. First, the diopter correction amount, which is refractive power information, is compared with a predetermined threshold value (S6). In this embodiment, assuming that an artifact occurs when each of the irradiation-side correction amount and the light-receiving-side correction amount is on the negative diopter side with respect to -12D, "-12D" is set as the refractive power threshold. Adopted. That is, the first range indicated by symbol A1 in FIG. 4B is the range on the plus diopter side of "-12D" in this embodiment. Also, the second range indicated by symbol A2 is "-12D" and the range on the minus diopter side in this embodiment. However, since the range of dioptric power in which artifacts due to the reflection of the objective lens 22 occur varies according to the optical design of the apparatus, a value according to the optical design of the apparatus may be used as the threshold value.

In this embodiment, when the refractive power of the eye to be examined is a value on the plus diopter side of "-12D", the first photographing mode is set (S6: No). On the other hand, if the refractive power of the subject's eye is "-12D" or a value on the negative diopter side, the second photographing mode is set (S6: Yes). The first photographing mode is the ineffective mode in the embodiment, and the second photographing mode is the effective mode in the embodiment.

In the first shooting mode, the process proceeds to S8, and shooting conditions other than the dioptric correction amount are adjusted according to the shooting mode (S8). After adjustment, a fundus image is taken (S9). At this time, light emission from the light sources 11c and 11d for observation may be stopped, and then the light sources 11a and 11b for photographing may be turned on. In this case, a photographed image of the fundus is obtained as a photographing result based on the visible light emitted from the light sources 11a and 11b.

In this embodiment, in the first photographing mode, a fundus image is photographed in a state in which the irradiation-side correction amount and the light-receiving side correction amount are matched (see FIG. 4A). At the time of photographing, the irradiation-side correction amount and the light-receiving side correction amount are the values immediately after adjustment in the focus adjustment process (S5). Therefore, the diopter correction amount is within a range in which artifacts do not pose a problem, and the fundus is photographed in a state in which the imaging surface and the slit-shaped members 15a and 15b are in a conjugate positional relationship with the fundus. Therefore, a good fundus image is captured.

On the other hand, in the second imaging mode, the irradiation side correction amount is shifted to the plus diopter side with respect to the value when the split index is matched (see FIG. 4B). As a result, the condensing position of the illumination light is moved away from the objective lens, so that artifacts due to reflection from the objective lens 22 are less likely to occur. In this embodiment, the value of the irradiation-side correction amount after the shift may be a fixed value, or may vary according to the light-receiving-side correction amount within a range that does not match the light-receiving-side correction amount. In this embodiment, the irradiation-side correction amount is shifted to "-10D", which is a value on the plus diopter side of the threshold. However, it is not necessarily limited to this, and may be changed to a threshold value.

Next, shooting conditions other than the dioptric correction amount are adjusted according to the second shooting mode. At this time, since the diopter correction amount in the irradiation optical system is deviated from the best focus, the slit light irradiated as the illumination light blurs on the fundus. As a result, the fundus reflected light passing through the opening of the slit 15b in the light receiving optical system is reduced, resulting in a decrease in the amount of received light.

Therefore, the control unit 100 sets any one of the light amount of the illumination light output from the light sources 11a and 11b or the light sources 11c and 11d, the gain of the image pickup device 28, and the exposure time to the second photographing mode as compared to the first photographing mode. Increase in shooting mode. As a result, deterioration in image quality due to blurring of the slit light emitted as the illumination light on the fundus as a result of the process of S7 is suppressed.

After adjusting the imaging conditions, the controller 100 captures a fundus image (S9). In the second photographing mode, a fundus image is photographed in a state in which the amount of correction on the irradiation side and the amount of correction on the light receiving side do not match. As a result, in this embodiment, the occurrence of artifacts is suppressed even in the case of photographing a myopic eye. At the time of photographing, the diopter correction amount in the light receiving optical system 10b is the value immediately after the adjustment in the focus adjustment process (S5). Therefore, since the fundus and the imaging plane are conjugated, the out-of-focus image is suppressed in the fundus image. In addition, in the second photographing mode, the slit 15a is arranged in a non-conjugated positional relationship with the fundus Er, so the slit light emitted as the illumination light is blurred on the fundus. However, since any one of the light intensity of the illumination light, the gain of the image sensor 28, and the exposure time is increased compared to the first imaging mode, it is easy to obtain a fundus image with an appropriate dynamic range.

In the method of suppressing artifacts on the fundus image by image processing, traces of image processing may remain in the image. On the other hand, in the present embodiment, since image processing for suppressing artifacts is not necessarily required, the fundus tissue is depicted more naturally in the fundus image.

Also, in the second imaging mode, the amount of illumination light or the exposure time is increased, so it is considered that the burden on the subject increases compared to the first imaging mode. However, since the time from the start of photographing (the start of illumination light irradiation for photographing) to the completion of photographing is relatively short, the extent of increase in the burden is considered to be relatively small. Therefore, even in the case of photographing an eye with a high degree of myopia, a fundus image in which artifacts are suppressed can be photographed without imposing a heavy burden on the subject.

<Second embodiment>
Next, with reference to FIG. 14, a second example of the fundus imaging apparatus according to the third embodiment will be described. The second embodiment will be described below, focusing on the differences from the first embodiment. In FIG. 14, the same components as in FIG. 2 are denoted by the same reference numerals, and detailed description thereof will be omitted unless otherwise specified. 14, illustration of the anterior ocular segment observation optical system 40 and the split target projection optical system 50 is omitted in contrast to the optical system of the first embodiment shown in FIG.

FIG. 14 shows the optical system of the fundus imaging device 1 according to the second embodiment. The fundus imaging apparatus 1 according to the second embodiment differs from the first embodiment in the position of the slit-shaped member (an example of the diaphragm). Specifically, in the first embodiment, the slit-shaped members 15a and 15b are arranged at conjugate positions with the imaging surface. On the other hand, as shown in FIG. 14, the slit-shaped members 150a and 150b in the second embodiment are arranged in advance at positions different from the conjugate positions of the imaging surface. In FIG. 14, both the slit-shaped member 150a arranged in the irradiation optical system 10a and the slit-shaped member 150b arranged in the light-receiving optical system 10b are arranged at positions different from the conjugate position of the imaging plane. ing. Both of the two slit-shaped members 150a and 150b are arranged on the positive diopter side with respect to the conjugate position of the imaging surface. As a result, the distance between the position where the objective lens collects the reflected light and the openings of the two slit-shaped members 150a and 150b is ensured. As a result, even if diopter correction is performed properly (just enough for the refractive power of the subject's eye) in each of the irradiation optical system and the light receiving optical system, the occurrence of artifacts based on the reflected light of the objective lens is suppressed. . In addition, compared to the first embodiment, it becomes easier to adjust the diopter correction amount in a short time during photographing. However, it is not necessarily limited to this, and either one of the two slit-shaped members 150a and 150b may be arranged at a conjugate position of the imaging surface.

<transformation example>
Although the above has been described based on the embodiments, the contents of the embodiments can be changed as appropriate in carrying out the present disclosure.

<Switching Control According to Pupil Size>
In the first embodiment, the difference value between the irradiation-side correction amount and the light-receiving side correction amount is adjusted by the control unit 100 according to the refractive power of the subject's eye. The difference value at this time may further take into consideration the size of the pupil. Further, the difference value may be adjusted in conjunction with the control operation set for each pupil size.

As an example, in the example shown in FIG. 5, the apparatus is controlled in a total of four cases (case 1 to case 4). In other words, one of the four shooting modes is selected according to the size of the pupil and the diopter value. For example, the imaging mode may be selected based on the size of the pupil detected from the front image of the anterior segment.

In the example shown in FIG. 5, (1) the clearance between the light projecting region P and the light receiving region R, (2) the alignment reference position in the XY directions, and (3) the difference value between the irradiation side correction amount and the light receiving side correction amount The three are changed by the controller 100 according to the pupil size (here, pupil diameter) and the diopter value (refractive power) of the subject's eye. Each condition is adjusted according to the result of comparing the pupil size (here, pupil diameter) and the diopter value (refractive power) of the subject's eye with respect to respective thresholds. As an example, "-12D" is used as the refractive power threshold. "4 mm" is used as the threshold for the pupil diameter. Any threshold is merely an example, and may be changed as appropriate.

In order to change the clearance between the light projecting region P and the light receiving region R, a pair of second light sources may be provided between the respective light sources 11a and 11b and the optical axis L. In this case, the clearance may be changed by switching the lighting light source. Alternatively, the light sources 11a and 11b may be changeable in distance with respect to the optical axis L. FIG. In this embodiment, the clearance is changed between a predetermined first interval and a second interval. Note that the second interval is assumed to be narrower than the first interval.

In the embodiment, the alignment reference position is switched between the first reference position and the second reference position. The first reference position is a position where the center of the light receiving region R and the corneal vertex (or pupil center) coincide. The second reference position is a position where the positional relationship between the center of the light-receiving region R and the corneal vertex (or the center of the pupil) is displaced from the first reference position by a predetermined distance.

The controller 100 guides the alignment based on the alignment deviation from the alignment reference position. Here, the guidance of alignment may be a so-called auto-alignment method or a manual alignment method. In the auto-alignment method, the control section 100 may drive and control the driving section based on the alignment deviation from the alignment reference position.

<Case 1 (an example of invalid mode)>
In Case 1, the pupil diameter is larger than the threshold and the refractive power is on the plus diopter side of the threshold. In this case, each condition is set as follows.
(1) Clearance between light projecting region P and light receiving region R: first interval (2) Alignment reference position in XY directions: first reference position (3) Difference value d between irradiation side correction amount and light receiving side correction amount: 0D
In case 1, since artifacts due to reflection at the objective lens are unlikely to occur, artifact suppression processing may not be performed. Moreover, since the pupil diameter is sufficiently large, a good fundus image can be taken without narrowing the clearance between the light projecting region P and the light receiving region R or without shifting the alignment reference position in the XY directions.

<Case 2 (an example of effective mode)>
In Case 2, the pupil diameter is larger than the threshold and the refractive power is on the minus diopter side of the threshold. In this case, each condition is set as follows.
(1) Clearance between light projecting region P and light receiving region R: first interval (2) Alignment reference position in XY directions: first reference position (3) Difference value d between irradiation side correction amount and light receiving side correction amount: 5D
In case 2, artifacts are more likely to occur than in case 1 because the refractive power is on the minus diopter side of the threshold. Therefore, the irradiation-side correction amount and the light-receiving-side correction amount are controlled to have different values. This can suppress artifacts. Also, since the pupil diameter is sufficiently large, there is no need to narrow the clearance between the light projecting region P and the light receiving region R or shift the alignment reference position in the XY directions.

<Case 3 (an example of effective mode)>
In Case 3, the pupil diameter is smaller than the threshold and the refractive power is on the plus diopter side of the threshold. In this case, each condition is set as follows.
(1) Clearance between light projecting region P and light receiving region R: Second interval (2) Alignment reference position in XY direction: Second reference position (3) Difference value d between irradiation side correction amount and light receiving side correction amount: 2.5D
In Case 3, since the pupil diameter is smaller than the threshold, the clearance between the light projecting region P and the light receiving region R is narrowed, and the alignment reference position in the XY directions is shifted with respect to the first reference position. In this embodiment, these controls tend to cause artifacts. Therefore, by setting the irradiation-side correction amount and the light-receiving-side correction amount to mutually different values, artifacts are suppressed. That is, compared to case 1, a larger value is given as the difference value d. Although the value of the difference value d in case 3 is smaller than the difference value d in case 2, it is not necessarily limited to this. The value of the difference value d in each case may be appropriately set for each optical system.

<Case 4 (an example of effective mode)>
In Case 4, the pupil diameter is smaller than the threshold and the refractive power is on the minus diopter side of the threshold. In this case, each condition is set as follows.
(1) Clearance between light projecting region P and light receiving region R: Second interval (2) Alignment reference position in XY direction: Second reference position (3) Difference value d between irradiation side correction amount and light receiving side correction amount: 5D
In Case 4, since the pupil diameter is smaller than the threshold, the clearance between the light projecting region P and the light receiving region R is narrowed, and the alignment reference position in the XY directions is shifted with respect to the first reference position. Also, the same value as in case 2 is used as the value of the difference value d between the irradiation-side correction amount and the light-receiving side correction amount. However, if artifacts are more likely to occur due to the control according to the pupil diameter, a larger value than in Case 2 may be set as the difference value d.

<Example of Modification of Dioptric Correction Optical System>
For example, in each embodiment, as the diopter correction optical systems 17 and 25, an optical system in which the diopter correction amount is set according to the lens interval is shown as an example. However, the dioptric correction optical system is not necessarily limited to this, and various optical systems can be employed. For example, in the case of the optical system shown in FIG. 2, instead of the lens 17a, the slit-shaped member 15a is displaced in the optical axis direction, thereby enabling dioptric correction in the irradiation optical system 10a. By displacing the slit-shaped member 15a in the optical axis direction, the position of the condensing point K is displaced in the optical axis direction. Similarly, by displacing the slit member 15b in the optical axis direction instead of the lens 25b, it is possible to correct the dioptric power in the light receiving optical system 10b. In this case, the lens 27 and the imaging element 28 may also be moved in conjunction with the slit-shaped member 25b. Furthermore, in this case, it becomes difficult for one driving unit to perform scanning by the slit-shaped member 15a and scanning by the slit-shaped member 15b. , may each have a drive unit.

<Photographing control during fluorescence photography>
Further, for example, in each of the above-described embodiments, the fundus imaging device not only captures a fundus image based on reflected light of the fundus, but also captures a fluorescent fundus image, which is a fundus image based on fluorescence emitted from the fundus. good.

In this case, illumination light is emitted as excitation light from the irradiation optical system. The wavelength range of the illumination light can be appropriately set according to the desired fluorescent material. The fluorescent substance may be a contrast agent (eg, indocyanine green, fluorescein, etc.) or an autofluorescent substance accumulated in the fundus (eg, lipofuscin).

In the light-receiving optical system, fluorescence from the fundus based on the excitation light is guided to the light-receiving element. When fluorescence imaging is performed, a barrier filter is arranged on the independent optical path of the light receiving optical system. The barrier filter has spectral characteristics that block light in the same wavelength range as the excitation light and allow fluorescence to pass through. As a result, the fluorescence is selectively received by the light receiving element, out of the fundus reflected light of the excitation light and the fluorescence from the fundus. As a result, a good fundus fluorescence image can be obtained. The fundus imaging device may have a driving unit for inserting and removing the barrier filter. Also, the insertion and removal of the barrier filter may be controlled by the controller.

The control unit may switch the shooting mode between the normal shooting mode and the fluorescence shooting mode. The normal photographing mode is set to photograph a fundus image based on fundus reflected light. The fluorescence imaging mode is set to capture a fluorescence fundus image. The control unit may control insertion and removal of the barrier filter according to the imaging mode. In this case, the controller retracts the barrier filter in the normal shooting mode. Also, the control unit inserts a barrier filter in the fluorescence imaging mode. Here, in the fluorescence imaging mode, the barrier filter blocks not only the fundus reflected light of the excitation light but also the reflected light from the objective lens. Therefore, there is no need to execute the various artifact suppression processes shown in the above embodiments in the fluorescence imaging mode. Therefore, in the fluorescence imaging mode, the artifact suppression process may not be executed by the control unit regardless of the refractive power of the subject's eye. For example, in an apparatus that suppresses the occurrence of artifacts by making the diopter correction amount (irradiation-side correction amount) in the irradiation optical system and the dioptric correction amount (light-receiving side correction amount) in the light-receiving optical system mismatch, In the fluorescence imaging mode, each value is adjusted according to the refractive power so that the irradiation-side correction amount and the light-receiving side correction amount match.

The present disclosure includes <fundus imaging devices A1 to A9>, <fundus imaging devices B1 to B5>, <fundus imaging devices C1 to C18>, <fundus imaging devices D1 to D5>, and <fundus imaging devices E1 to E8>. includes at least the aspects described in . Elements in each aspect may be introduced into another aspect as appropriate.

<Fundus imaging device A1 to A9>
(1) Fundus imaging device A1:
An illumination optical system that illuminates the fundus of the subject's eye through an objective lens, and a light receiving device that shares the objective lens with the illumination optical system and further includes a light receiving element that receives the fundus reflected light of the illumination light. an imaging optical system including an optical system, and acquiring a fundus image based on a signal from the light-receiving element, wherein the refractive power for acquiring refractive power information, which is information about the refractive power of the subject's eye an information acquisition unit; and control means for executing artifact suppression processing for suppressing the occurrence of artifacts based on the reflection of the illumination light by the objective lens,
The control means selects an imaging mode between an invalid mode in which artifact suppression processing is not performed when capturing a fundus image and an effective mode in which artifact suppression processing is performed when capturing a fundus image, based on the refractive power. to switch.

(2) Fundus imaging device A2: In the fundus imaging device A1, the refractive power of the eye to be examined is broadly divided into a first range and a second range on the negative diopter side of the first range, The control means switches to the invalid mode when the refractive power of the eye to be inspected is within the first range, and switches to the effective mode when the refractive power of the eye to be inspected is within the second range.

(3) Fundus photographing device A3: In the fundus photographing device A1 or A2, the illumination optical system irradiates the fundus with illumination light as excitation light to generate fluorescence from fluorescent substances present in the fundus, thereby In the light-receiving optical system, a barrier filter that blocks the illumination light and allows the fluorescence to pass through is arranged in an independent optical path of the light-receiving optical system so that it can be freely inserted and removed. In addition, when the barrier filter is inserted into the independent optical path, the photographing mode is set to the invalid mode regardless of the refractive power.

(4) Fundus imaging device A4: In any one of the fundus imaging devices A1 to A3, in the effective mode, the control means, as the artifact suppression processing, performs a plurality of images with different positions of the artifacts with respect to the tissue of the eye to be examined. are captured, and a composite image is generated by synthesizing the plurality of fundus images.

(5) Fundus photographing device A5: In any one of the fundus photographing devices A1 to A4, the photographing optical system includes a slit forming unit that forms a slit-like illumination light on the fundus of the eye to be examined, and a slit-like slit on the fundus. A scanning unit that scans the formed illumination light in a direction that intersects the slit, and a projection area through which the illumination light passes on the pupil of the eye to be inspected are separated from each other with respect to the scanning direction of the illumination light. a light emitting/receiving separation unit formed at a position and forming a light receiving region from which the fundus reflected light of the illumination light is extracted on the pupil of the eye to be inspected so as to be sandwiched between the two light projecting regions; A fundus image is captured based on the fundus reflected light extracted from the light receiving area.

(6) Retinal imaging device A6: In the retinal imaging device A5, in the effective mode, the control means further performs the artifact suppression processing based on the illumination light projected from one of the two light projection areas. A first fundus image, which is a fundus image, and a second fundus image, which is a fundus image based on the illumination light projected from the other of the two light projection areas, are photographed, and the first fundus image and the A composite image is generated using at least two of the second fundus images.

(7) Fundus photographing device A7: In the fundus photographing device A5, in the invalid mode, the control means photographs a fundus image based on the illumination light projected simultaneously from both of the two light projection areas, In the effective mode, as the artifact suppression processing, whether or not to pass the illumination light is individually set for each of the two light projection regions, and light is selectively projected from one of the two light projection regions. The fundus image is captured based on the illuminated illumination light.

(8) Fundus photographing device A8: In the fundus photographing device A4, the positional relationship between the optical axis of the photographing optical system and the visual axis of the eye to be examined is changed to change the position of the tissue of the eye to be examined in the fundus image. A position adjusting unit for adjusting the position of the artifact is provided, and the control means photographs the plurality of fundus images by changing the positional relationship for each photographing in the valid mode.

(9) Retinal imaging device A9: In any one of the retinal imaging devices A1 to A3, the irradiation side correction amount that is the dioptric correction amount in the irradiation optical system and the light receiving side correction amount that is the dioptric correction amount in the light receiving optical system and a dioptric correction optical system that independently adjusts and, in the invalid mode, the control means captures the fundus image by matching the irradiation side correction amount and the light reception side correction amount, In the effective mode, the fundus image is captured with the irradiation-side correction amount and the light-receiving-side correction amount different from each other.

<Fundus imaging device B1 to B5>
(10) Fundus photographing device B1: an irradiation optical system for irradiating a slit-shaped illumination light onto the fundus of the eye to be inspected through an objective lens, the irradiation optical system and the objective lens are shared, and further, the fundus reflection of the illumination light A photographing optical system including a light-receiving optical system having an imaging surface on which a fundus image is formed based on light, a scanning unit, a diopter correction optical system for correcting diopter in the photographing optical system, and the objective lens. and a fundus photographing apparatus for photographing a fundus image in a state in which a diaphragm is placed at a position different from a fundus conjugate position with respect to both of said dioptric correction optical system.
(11) Fundus photographing device B2: In the fundus photographing device B1, the diaphragm is arranged in advance at a position different from the imaging plane and the conjugate position of the imaging plane.
(12) Fundus photographing device B3: In the fundus photographing device B2, the diaphragm is arranged in advance at a position away from the conjugate position of the imaging plane on the plus diopter side.

(13) Fundus photographing device B4: In the fundus photographing device B2 or B3, the control means controls the dioptric correction optical system when photographing the fundus image, and the imaging plane is the subject's eye. Adjust so that it is placed at the fundus conjugate position.

(14) Fundus photographing device B5: In the fundus photographing device B1, the dioptric correction optical system includes the irradiation side correction amount, which is the dioptric correction amount in the irradiation optical system, and the light reception side correction amount, which is the dioptric correction amount in the light receiving optical system. and the side correction amount can be adjusted independently, and the control means controls the dioptric correction optical system when photographing the fundus image, and adjusts the irradiation side correction amount and the light receiving side correction amount. to different values.

<Fundus imaging device C1 to C18>
(15) Fundus photographing device C1: an irradiation optical system that irradiates the fundus of the eye to be inspected with illumination light through an objective lens, and the objective lens is shared with the irradiation optical system, and the fundus reflected light of the illumination light is and a light-receiving optical system having a light-receiving element for receiving light, wherein the fundus imaging apparatus acquires a fundus image based on a signal from the light-receiving element, wherein irradiation-side correction is a dioptric correction amount in the irradiation optical system. and a light-receiving side correction amount, which is a diopter correction amount in the light-receiving optical system. a control means for setting the side correction amount and the side correction amount to mutually different values.

(16) Fundus photographing device C2: In the fundus photographing device B5 or C1, the control means adjusts the light-receiving side correction amount according to the refractive power of the eye to be examined, and adjusts the correction amount via the dioptric correction optical system. The irradiation-side correction amount is set so that the condensing position of the illumination light is arranged at a position farther from the objective lens with respect to an intermediate image plane of the fundus formed through the objective lens.

(17) Fundus photographing device C3: In the fundus photographing device B5 or C2, the control means adjusts the light receiving side correction amount according to the refractive power of the eye to be examined, and adjusts the irradiation side correction amount to the light receiving side correction amount. Set to a value with a smaller absolute value than the correction amount.

(18) Fundus imaging device C4: In any one of the fundus imaging device B5 or C1 to C3, the control means determines the difference value between the first imaging mode, the irradiation side correction amount, and the light reception side correction amount. The photographing mode is switched between a second photographing mode in which the fundus image is photographed by adjusting to a value larger than that in the first photographing mode, according to the refractive power of the subject's eye.

(19) Fundus photographing device C5: In the fundus photographing device C4, the control means adjusts the difference value in consideration of the size of the pupil of the subject's eye.

(20) Fundus photographing device C6: In the fundus photographing device C4 or C5, in the first photographing mode, the control means matches the irradiation-side correction amount and the light-receiving side correction amount to obtain the fundus image. In the second photographing mode, the fundus image is photographed with the irradiation-side correction amount and the light-receiving-side correction amount different from each other.
(21) Fundus imaging device C7: In any one of the fundus imaging devices C4 to C6, the refractive power of the eye to be examined has a first range and a second range on the negative diopter side with respect to the first range. The control means switches to the first photographing mode when the refractive power of the eye to be examined is in the first range, and switches to the first photographing mode when the refractive power of the eye to be examined is in the second range. 2 Switch to shooting mode.

(22) Fundus imaging device C8: Any one of the fundus imaging devices C2 to C7 has a refractive power information acquisition unit that acquires refractive power information relating to the refractive power of the subject's eye, and the control means controls the refractive power information. Based on this, the irradiation-side correction amount and the light-receiving side correction amount are set.

(23) Fundus imaging device C9: In the fundus imaging device C8, the refractive power information acquisition unit detects the focus state in the light receiving optical system, and acquires the refractive power information based on the detection result of the focus state.

(24) fundus imaging device C10: in fundus imaging device B5 or any of C1 to C9,
an optical path coupling unit disposed between the objective lens and the light-receiving element for coupling an optical path of the irradiation optical system and an optical path of the light-receiving optical system; and the light receiving optical system, a first dioptric correction optical system arranged on one optical path, and on the other optical path of the one, or on a common optical path of the irradiation optical system and the light receiving optical system and a second dioptric correction optical system disposed thereon, wherein the control means individually controls the first dioptric correction optical system and the second dioptric correction optical system to control the irradiation The side correction amount and the light receiving side correction amount are set to mutually different values.

(25) Retinal imaging device C11: In the retinal imaging device C10, a first driving unit for driving at least one optical element included in the first dioptric correction optical system, and a driving unit included in the second dioptric correction optical system a second driving section for driving at least one optical element, wherein the control section independently controls the first driving section and the second driving section;

(26) Fundus photographing device C12: In any one of the fundus photographing devices C1 to C11, the irradiation optical system forms a local illumination area in a part of the photographing range of the fundus, and is between the objective lens and is disposed on the optical path of the light-receiving optical system with the dioptric correction optical system interposed therebetween, and causes the light-receiving element to receive reflected light from a local photographing area that is a part of the photographing range, and the photographing. A harmful light removing section for removing light from outside the area, and a scanning section for synchronously scanning the local illumination area and the local imaging area on the fundus.

(27) Fundus photographing device C13: In the fundus photographing device B5 or C12, the harmful light removal unit is configured to remove at least the objective lens and the It is arranged at a position conjugate with the fundus with respect to the dioptric correction optical system.

(28) Retinal imaging device C14: In any one of the retinal imaging devices B5, C12 and C13, the dioptric correction optical system is configured such that the irradiation side correction amount and the It includes a telecentric optical system that maintains the image height on the image side regardless of the combination with the light receiving side correction amount.

(29) Fundus photographing device C15: In any one of the fundus photographing devices B5, C12 to C14, the local illumination area and the local photographing area are each formed in a slit shape.

(30) Fundus imaging device C16: In the fundus imaging device C15, a first slit-shaped member having a slit-shaped opening is provided on the optical path of the irradiation optical system, and the harmful light removing unit is the slit-shaped opening. and a second slit-shaped member that guides light that has passed through the opening to the light receiving element, and the scanning unit includes the first slit-shaped member and the second slit-shaped member, and the first slit-shaped member and a driving unit that moves the second slit-shaped member in a direction intersecting the optical axis.

(31) Fundus imaging device C17: In the fundus imaging device C15, the scanning unit is a first scanning unit that is an optical scanner arranged on the irradiation optical system, and is separate from the first scanning unit, a second scanning unit arranged on the light receiving optical system, wherein the light receiving element is a CMOS element, and line exposure by a rolling shutter function of the CMOS element is synchronized with scanning by the first scanning unit. Accordingly, the light receiving element serves as both the harmful light removing section and the second scanning section.

(32) Fundus photographing device C18: In any one of the fundus photographing devices B5, C12 to C14, the local illumination area and the local photographing area are each formed in a spot shape.

<Fundus imaging device D1 to D5>
(33) Fundus photographing device D1: an irradiation optical system that irradiates the fundus of the eye to be inspected with illumination light via an objective lens, and the objective lens is shared with the irradiation optical system, and further, the fundus reflected light of the illumination light is a light-receiving optical system having a light-receiving element that receives light; and controlling one or both of the irradiation optical system and the light-receiving optical system to obtain at least two fundus images under different photographing conditions. based on the signal from the light-receiving element, and an imaging processor for synthesizing at least two fundus images obtained under different imaging conditions to obtain a synthesized image.

(34) Fundus photographing device D2: In the fundus photographing device D1, the control means controls the positional relationship between the optical axis of the photographing optical system and the visual axis of the eye to be inspected without changing the positional relationship between the photographing optical system and the visual axis of the subject's eye. of the fundus image.

(35) Fundus photographing device D3: In the fundus photographing device D1 or D2, the photographing optical system includes a diopter correction optical system, and the control means controls at least two images of the fundus on which the composite image is based. When an image is captured, the dioptric correction amount in the dioptric correction optical system as the imaging condition is changed for each imaging by controlling the dioptric correction optical system.

(36) Fundus photographing device D4: In the fundus photographing device D1 or D2, the control means, when photographing at least two fundus images to be the basis of the composite image, directs the reflected light from the fundus to the objective. By controlling the photographing optical system, the state of separation of the illumination light reflected by the lens from the harmful light is made different for each photographing.

(37) Fundus photographing device D5: In any one of the fundus photographing devices D1 to D4, the illumination light is visible light, and the control means acquires the two fundus images that form the basis of the composite image. Then, a continuous photographing process of photographing two fundus images at predetermined intervals in the order of the second fundus image and the first fundus image is executed.

<Fundus imaging device E1 to E8>
(38) Fundus photographing device E1: A photographing optical system comprising an irradiation optical system for irradiating illumination light onto the fundus of an eye to be inspected, and a light receiving optical system including an imaging device for receiving return light of the illumination light from the fundus. and a fundus imaging device for acquiring a fundus image, which is a front image of the fundus, based on a light receiving signal from the imaging device, wherein the imaging optical system forms a slit-shaped local imaging region. an optical element; and a scanning unit that scans the imaging area with respect to the fundus, wherein the optical element sets the width of the imaging area to a first width and a second width that is wider than the first width. and the control means acquires a first fundus image as a photographed image based on scanning of the photographing area of the first width, and obtains a first fundus image of the second width. A second fundus image is obtained as a photographed image based on scanning of the photographing area.

(39) Fundus photographing device E2: In the fundus photographing device E1, the control means acquires a color image of the fundus as the first fundus image by changing the wavelength of the illumination light for each photographed image. A fluorescence image of the fundus is acquired as a bifundus image.

(40) Fundus photographing device E3: In the fundus photographing device E1, the control means selects either the first fundus image or the second fundus image based on the information regarding the size of the pupil of the eye to be examined. Selectively acquire.

(41) Fundus imaging device E4: In any one of the fundus imaging devices E1 to E3, the optical element is a rotating body in which a plurality of slit openings are arranged side by side on one circumference, and the scanning unit An optical chopper that includes the rotator, and rotates the rotator so that the plurality of slit openings are continuously traversed with respect to the optical path of the illumination light or the return light, wherein the rotator comprises the A first area in which one or two or more first slit openings corresponding to the first width are continuously arranged, and one or two consecutive second slit openings corresponding to the second width. and a second area arranged as described above, wherein the control means acquires the first fundus image based on a signal from the imaging device exposed during a first period in which the first area passes through the optical path. Then, the second fundus image is acquired based on the signal from the imaging element exposed during the second period in which the second area passes through the optical path.

(42) Fundus photographing device E5: In the fundus photographing device E4, the control means further controls the optical chopper to continuously rotate the rotating body, and based on the signal from the imaging device, The fundus images are sequentially obtained as observation images at a constant frame rate.

(43) Fundus photographing device E6: In the fundus photographing device E5, the control means controls, as the observation images, a first observation image based on a signal from the image sensor exposed in the first period and and a second observation image based on the signal from the image pickup device exposed at , alternately obtained each time the first period and the second period are switched, and when obtaining the observation image, In the second period, one of the light amount of the illumination light and the gain of the signal from the imaging device is reduced compared to the first period.

(44) Fundus photographing device E7: In the fundus photographing device E6, the control means causes each frame of the observation image to be exposed in both at least part of the first period and at least part of the second period. obtained based on the signal from the image sensor.

(45) Fundus photographing device E8: In any one of the fundus photographing devices E1 to E7, the photographing optical system has a diopter correction optical system for correcting a diopter error in the subject's eye, and the control means and selectively acquiring either the first fundus image or the second fundus image according to a diopter correction amount in the diopter correction optical system.

1 fundus photographing device 10 photographing optical system 10a irradiation optical system 10b light receiving optical system 17, 25 dioptric correction optical system 22 objective lens 100 controller E eye to be examined Er fundus

Claims (4)

An irradiation optical system that irradiates a slit-shaped illumination light onto the fundus of the subject's eye through an objective lens, the irradiation optical system and the objective lens are shared, and an image of the fundus is formed based on the fundus reflected light of the illumination light. a photo-taking optical system including a light-receiving optical system having an imaging surface with a scanning section;
a diaphragm provided in the imaging optical system for forming the slit-shaped illumination light or for forming a local imaging area on the fundus ;
a diopter correction optical system that includes a lens disposed between the objective lens and the diaphragm, and corrects the diopter in the imaging optical system by moving the lens according to the refractive power of the subject's eye; with
A fundus photographing apparatus for photographing a fundus image with the diaphragm placed at a position different from a fundus conjugate position with respect to both the objective lens and the dioptric correction optical system. The dioptric correction optical system is capable of independently adjusting an irradiation-side correction amount, which is a dioptric correction amount in the irradiation optical system, and a light-receiving-side correction amount, which is a dioptric correction amount in the light-receiving optical system,
2. The fundus oculi according to claim 1 , further comprising control means for controlling said dioptric correction optical system and setting said irradiation-side correction amount and said light-receiving side correction amount to different values when said fundus image is taken. photographic equipment. an irradiation optical system that irradiates the fundus of the eye to be inspected with illumination light through the objective lens;
a light-receiving optical system that shares the objective lens with the irradiation optical system and further includes a light-receiving element that receives the fundus reflected light of the illumination light,
A fundus imaging device that acquires a fundus image based on a signal from the light receiving element,
a first lens arranged in the irradiation optical system; and a second lens, which is a second lens different from the first lens and arranged in the light receiving optical system, wherein the first lens and the second Diopter correction for independently adjusting an irradiation-side correction amount, which is the dioptric correction amount in the irradiation optical system, and a light-receiving-side correction amount, which is the dioptric correction amount in the light-receiving optical system, by moving the lenses respectively. an optical system;
a control means for controlling the diopter correction optical system and setting the irradiation-side correction amount and the light-receiving side correction amount to mutually different values. 4. The fundus photographing apparatus according to claim 2, wherein said control means controls said dioptric correction optical system in consideration of the pupil size of an eye to be examined.

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