JP2021037172A - Ocular fundus imaging device - Google Patents

Abstract

To provide an ocular fundus imaging device that properly adjusts a focus and easily takes an ocular fundus image.SOLUTION: An ocular fundus imaging device comprises a light emitting part 11, an irradiating optical system 10, a light receiving optical system 20, a focus adjustment part 40, and a control unit 70. The ocular fundus imaging device also comprises a light limiting part 23 capable of switching an illumination depth in at least one of the irradiating optical system 10 and the light receiving optical system 20 between a first illumination depth and a second illumination depth shallower than the first illumination depth. The control unit 70 of the ocular fundus imaging device performs illumination depth control processing for setting the second illumination depth when adjusting a focus position on the basis of an observation image, and setting the first illumination depth when taking a photographic image.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to a fundus photography apparatus.

Conventionally, as a kind of fundus photography device, a device that captures a frontal image as a fundus image by scanning light on the fundus is known.

As a scanning fundus photography apparatus, an apparatus provided with a confocal optical system is known (see, for example, Patent Document 1). In a confocal optical system, for example, one in which an aperture for removing noise light is arranged at a fundus conjugate position on a light receiving light path is known.

For example, in Patent Document 1, a plurality of fundus images are acquired while changing the focus position, and as a result of comparing the imaging states of the fundus images, the focus position when obtaining a captured image is a suitable imaging state. A device that adjusts to the position where

JP-A-2009-291253

However, conventionally, it has been difficult to properly adjust the focus when there is a height difference due to a disease or curvature in the fundus.

The technical subject of the present disclosure is to solve at least one of the problems of the prior art and to provide a fundus photography apparatus capable of appropriately adjusting the focus and taking a fundus image.

The fundus imaging apparatus according to the first aspect of the present disclosure is an irradiation optical system that emits observation light and imaging light, and an irradiation optical system that irradiates the fundus of the eye to be inspected with light from the light emitting portion. An irradiation optical system having a scanning means for scanning the light, a light receiving optical system having a light receiving element for outputting a light receiving signal by receiving the return light of the light from the fundus, the irradiation optical system, and the above. A fundus imaging device that includes a focus adjusting unit that adjusts a focus position in at least one of the light receiving optical systems and a control means, and captures a fundus image based on a light receiving signal from the light receiving element. Further, an illumination depth switching unit capable of switching the illumination depth in at least one of the light receiving optical systems between a first illumination depth and a second illumination depth shallower than the first illumination depth is provided. The control means acquires an observation image as the fundus image based on the received signal of the return light by the observation light, and sets the second illumination depth when adjusting the focus position based on the observation image. At the same time, when the photographed image is photographed as the fundus image based on the received signal of the return light by the photographed light, the illumination depth control process set to the first illumination depth is executed.

According to the present disclosure, it is easy to properly adjust the focus and take a fundus image.

It is a figure which shows the schematic structure of the optical system of the fundus photography apparatus 1. It is a figure which shows the schematic structure of the optical system of the fundus photography apparatus 1 when the lens attachment 3 is attached. It is a block diagram which shows the electrical structure of the fundus photography apparatus 1. It is a figure which showed an example of the fundus image taken in the state that the size of a passing area is set to the first size. It is a figure which showed an example of the fundus image taken in the state that the size of the passing region was set to the second size, and further, the focus position was set to the surface side of the retina. It is a figure which showed an example of the fundus image taken in the state that the size of a passing region was set to the second size, and further, the focus position was set to the choroid side. It is a flowchart which showed the flow of the shooting operation in an Example. It is a figure which showed the observation image which is displayed on the monitor 80 for accepting the setting operation of the observation part.

"Overview"
The fundus photography apparatus (see FIGS. 1 to 3) exemplified in the present disclosure includes a light emitting unit, an irradiation optical system, a light receiving optical system, a focus adjusting unit, an illumination depth adjusting unit, and a control unit (control means). , Equipped with. The fundus photography device is a scanning device. The fundus photography device may be, for example, a two-dimensional scan type device that scans a spot-shaped luminous flux two-dimensionally on the fundus, or scans a slit-shaped luminous flux in a direction intersecting the longitudinal direction of the slit. It may be a slit scan (also referred to as a line scan) type device.

The light emitting unit emits observation light and photographing light. The wavelength bands may be different from each other between the observation light and the photographing light. For example, the observation light may be infrared light, and the photographing light may be visible light. Further, either the observation light or the photographing light may be selectively emitted from the light emitting unit.

The irradiation optical system irradiates the fundus of the eye to be inspected with light from the light emitting portion. Further, the irradiation optical system has a scanning unit (also referred to as a scanning means or an optical scanner) that scans light on the fundus.

The light receiving optical system has at least a light receiving element.

The light receiving element outputs a light receiving signal by receiving the return light of the light (observation light and illumination light) from the fundus. A fundus image (frontal image of the fundus) is taken based on the signal from the light receiving element.

The focus adjusting unit adjusts the focus position in the irradiation optical system and the light receiving optical system. The focus adjusting unit may be provided with, for example, a moving lens, a variable focus lens such as a liquid crystal lens, or an optical system capable of changing the optical path length. It may be a lens. The optical system whose optical path length can be changed may be, for example, one or more lenses, mirrors, or a combination thereof.

The illumination depth adjustment unit can switch the illumination depth (also referred to as the depth of field) in at least one of the irradiation optical system and the light receiving optical system. The illumination depth may be switched between at least a first illumination depth and a second illumination depth that is shallower than the first illumination depth.

The deeper the illumination depth, the easier it is to acquire a fundus image having a larger amount of information in the depth direction (see FIG. 4). On the other hand, the deeper the illumination depth, the less the change in image quality with respect to the change in focus position. On the other hand, when the illumination depth is the shallower second illumination depth, the change in image quality with respect to the change in the focus position becomes clearer (see FIGS. 5 and 6).

The illumination depth adjusting unit may be, for example, the following light limiting unit or a beam diameter switching unit.

The light limiting unit is arranged at a position conjugate with the fundus of the eye in the light receiving optical system. The light limiting unit regulates a region through which the return light guided to the light receiving element passes (hereinafter, referred to as a passing region). The light limiting unit may be a diaphragm (so-called confocal diaphragm). In the spot scan type, for example, a pinhole may be used as a light limiting unit. Further, in the slit scan type, the slit may be used as a light limiting unit. Further, as another configuration of the light limiting unit, it is conceivable that the light receiving element and the light limiting unit are integrated. In this case, the region to be effectively exposed on the light receiving surface of the light receiving element may be controllable. Such a configuration may be, for example, an electronic shutter or a liquid crystal shutter. Further, in the case of a slit scan type optical system, an integrated configuration of the light receiving element and the light limiting unit may be realized by using the rolling shutter function in CMOS.

In the present disclosure, the term "conjugate" is not necessarily limited to a perfect conjugate relationship, and includes "substantially conjugate". For example, the light limiting unit may be arranged at a position deviated from the perfect fundus conjugate position within a range permitted in relation to the purpose of use of the fundus image (for example, observation, analysis, etc.).

In the present embodiment, the light limiting unit sets the size of the passing region to the first size corresponding to the first illumination depth and the second size to be narrower than the first size and to correspond to the second illumination depth. It is possible to switch between. In this case, the size of the passing region may be switched by selectively arranging at least two light limiting portions having different sizes of the passing region on the light receiving optical path. Further, the size of one passing region of the light limiting unit may be switchable in at least two steps.

The beam diameter switching unit sets the beam diameter of the light emitted from the irradiation optical system to the eye to be inspected by the first beam diameter corresponding to the first illumination depth and the second beam diameter larger than the first beam diameter. It may be possible to switch between the illumination depth of the above and the corresponding second beam diameter. The beam diameter switching unit may be, for example, a variable beam expander arranged in the irradiation optical system. In this case, the variable beam expander may be arranged between the light emitting unit and the scanning unit.

The control unit is a processor that controls various operations of the fundus photography device. The control unit may be composed of, for example, a CPU, a RAM, a ROM, and the like.

The control unit executes the illumination depth control process. In the illumination depth control process, the illumination depth is changed at least between when the focus position is adjusted based on the observed image and when the captured image is captured.

The "observation image" referred to here is a fundus image generated based on the received signal of the return light by the observation light. The "photographed image" is a fundus image generated based on the received signal of the return light generated by the photographed light.

When adjusting the focus position based on the observed image, a shallower second illumination depth is set. As a result, the change in image quality with respect to the change in the focus position becomes larger than in the case where the first illumination depth is set (for example, FIG. 4 ⇒ FIG. 5, FIG. 6). As a result, in each case where there is a height difference due to a disease or a height difference due to the curvature of the fundus in the fundus region which is the imaging range, the focused portion on the fundus region. Can be easily confirmed through the observed image and the photographed image.

Further, when the captured image is acquired, the illumination depth is set to the first illumination depth, so that it becomes easy to acquire the fundus image having a larger amount of information in the depth direction. At this time, when the illumination depth switching unit is the light limiting unit, the size of the passing region becomes wider, so that the light receiving efficiency becomes higher. As a result, a brighter captured image can be easily captured (see FIG. 4). Further, when the illumination depth switching unit is the beam diameter adjusting unit, the beam diameter becomes thicker, so that it becomes easier to take a fundus image having better resolution.

Further, the control unit may further execute the focus control process. In the focus control process, the control unit sequentially acquires the observation image in a state set to the second illumination depth, and drives the focus adjustment unit based on the information regarding the imaging state detected from the observation image. This makes it easier to capture a captured image whose focus is properly adjusted with respect to the fundus.

The control unit may execute a setting process for setting a part of the imaging range as an observation site. Further, in the above-mentioned focus control process, the control unit may drive the focus adjustment unit based on the information regarding the imaging state at the observation site. As a result, a fundus image in which the focus is appropriately adjusted with respect to the observation site can be obtained as a captured image.

The observation site may be set based on, for example, an examiner's setting operation. In this case, the control unit may accept the setting operation of the observation part in the setting process and set the observation part based on the setting operation. The setting operation may be an operation of designating an observation site on the observation image. As a result, it is possible to take a fundus image in which the focus is appropriately adjusted with respect to the desired observation site specified by the examiner from the observation image.

Further, the observation site may be set based on, for example, position information that identifies the observation site on the observation image. The position information may indicate, for example, a diseased part or the like identified based on the test result of another fundus examination device (for example, OCT, perimeter, etc.). In addition, it may indicate a diseased part identified in a past examination. In these cases, the location information may be acquired from the memory accessible from the control unit.

The ophthalmologic imaging apparatus may be capable of photographing the eye to be inspected at a second angle of view which is 90 ° or more (90 ° or more at the center of the pupil). In this case, for example, an objective optical system having a shooting angle of view of 90 ° or more may be provided between the operation unit and the eye to be inspected. Here, the shooting angle of view indicates the shooting range of the fundus image.

The wider the angle of view, the larger the height difference due to the curvature of the fundus, so that the illumination depth control process is more useful.

"Example"
Hereinafter, a typical embodiment of the present invention will be described with reference to the drawings. First, with reference to FIGS. 1 to 3, the overall configuration of the fundus photography device 1 (hereinafter referred to as the device 1) will be described. In this embodiment, the present device 1 has an SLO (Scanning Light Ofthalmoscop: SLO) configuration. This device 1 is a device that captures a frontal image of the fundus Er of the eye E to be inspected. The apparatus 1 scans the light on the fundus Er and receives the return light from the fundus Er to acquire a front image of the fundus Er.

In the following description, the present apparatus 1 obtains a fundus image by two-dimensionally scanning the light focused on the spot on the observation surface based on the operation of the scanning unit (optical scanner). However, the present invention is not necessarily limited to this, and the present device 1 may be a so-called slit scan type device. In this case, the slit-shaped luminous flux is scanned on the observation surface.

<Optical system>
The optical system provided in the present apparatus 1 will be described with reference to FIG. As shown in FIG. 1, the apparatus 1 includes an irradiation optical system 10 and a light receiving optical system 20. The present device 1 captures a fundus image using these optical systems 10 and 20.

The apparatus 1 of the present embodiment switches the shooting angle of view by switching the lens configuration in the objective optical unit. Specifically, the shooting angle of view is selectively switched to one of the two predetermined shooting angles of view by attaching / detaching the lens attachment 3 (see FIG. 2). Here, the narrower shooting angle of view is referred to as "first angle of view", and the wider shooting angle of view is referred to as "second angle of view". For example, the first angle of view may be less than 90 ° and the second angle of view may be 90 ° or more. For example, the first angle of view may be about 45 ° to 60 °, and the second angle of view may be about 90 ° to 150 °.

First, with reference to FIG. 1, an optical system when the shooting angle of view is the first angle of view will be described. In this embodiment, when the lens attachment 3 (see FIG. 2) is not attached, the shooting angle of view is set to the first angle of view.

<Irradiation optical system>
The irradiation optical system 10 includes a scanning unit 16 and an objective optical unit 17. The objective optical unit 17 includes at least one lens. Further, as shown in FIG. 1, the irradiation optical system 10 further includes a light emitting unit 11, a collimating lens 12, a perforated mirror 13, and a lens 14 (a part of the focus adjusting unit 40 in this embodiment). And has a lens 15.

The light emitting unit 11 is a light source of the irradiation optical system 10. In this embodiment, the light from the light emitting unit 11 is used as the observation light and the photographing light. The light emitting unit 11 of this embodiment can emit light of a plurality of colors simultaneously or selectively. As an example, in this embodiment, the light emitting unit 11 emits light of a total of four colors, that is, three colors in the visible region of blue, green, and red, and one color in the infrared region. The light of each color can be emitted at the same time in any combination. The light emitting unit 11 may be formed including, for example, a laser diode (LD), a super luminescent diode (SLD), and the like.

Hereinafter, unless otherwise specified, in the present embodiment, infrared light will be used as observation light, and visible light will be used as shooting light.

The return light from the eye E to be examined with respect to the light emitted from the light emitting unit 11 may be, for example, the reflected light from the tissue of the eye E to be inspected. Further, the light from the light emitting unit 11 may be light (for example, fluorescence) emitted from the tissue based on the irradiation.

However, for convenience of explanation, in the following description, unless otherwise specified, the light of each color emitted from the light emitting unit 11 will be described as being used for photographing the reflected image by the fundus reflected light.

As the reflection image, any or all of an infrared image, a color image, a red-free image, a monochromatic visible image, and the like may be taken.

In this embodiment, the light emitted from the light emitting unit 11 is guided to the fundus Er in the path of the light beam shown in FIG. That is, the light from the light emitting unit 11 passes through the opening formed in the perforated mirror 13 via the collimating lens 12, passes through the lens 14 and the lens 15, and then heads toward the scanning unit 16. The laser beam reflected by the scanning unit 16 passes through the dichroic mirror 51, passes through the objective optical unit 17, and then irradiates the fundus Er of the eye E to be inspected. As a result, the light emitted from the light emitting unit 11 is reflected and scattered by the fundus Er. This light (that is, the fundus reflected light) is emitted from the pupil as return light.

The scanning unit 16 (also referred to as an “optical scanner”) is a unit for scanning the laser beam emitted from the light emitting unit 11 on the fundus Er. In the following description, unless otherwise specified, the scanning unit 16 includes two optical scanners having different scanning directions. That is, it includes an optical scanner 16A for main scanning (for example, scanning in the X direction) and an optical scanner 16B for sub-scanning (for example, scanning in the Y direction).

The objective optical unit 17 is an objective optical system of the present device 1. The objective optical unit 17 is used to irradiate the eye E to be inspected with the light scanned by the scanning unit 16 and guide it to the fundus Er. Therefore, the objective optical unit 17 forms a turning point P in which the light passing through the scanning unit 16 is swirled. The turning point P is formed on the reference optical axis L1 of the irradiation optical system 10 at a position optically conjugate with the scanning unit 16 with respect to the objective optical unit 17. In FIG. 1, the objective optical unit 17 of the apparatus 1 is shown as a refraction system, but the present invention is not limited to this, and may be a reflection system.

The laser light that has passed through the scanning unit 16 passes through the objective optical unit 17 and is irradiated to the fundus Er in the swirl point P. Therefore, the laser beam that has passed through the objective optical unit 17 is swirled around the swirl point P as the scanning unit 16 operates. As a result, in this embodiment, the laser beam is two-dimensionally scanned on the fundus Er. The laser light applied to the fundus Er is focused at the focusing position (for example, the surface of the retina).

<Receiving optical system>
Next, the light receiving optical system 20 will be described. The light receiving optical system 20 has one or more light receiving elements. For example, as shown in FIG. 1, the light receiving optical system 20 may have a plurality of light receiving elements 25, 27, 29. In this case, the return light from the fundus Er is received by at least one of the light receiving elements 25, 27, and 29.

As shown in FIG. 1, in the light receiving optical system 20 in this embodiment, each member arranged from the objective optical unit 17 to the perforated mirror 13 may be shared with the irradiation optical system 10. In this case, the return light from the fundus Er is guided back to the perforated mirror 13 in the optical path of the irradiation optical system 10. The perforated mirror 13 removes at least a part of noise light due to reflection by the cornea of the eye E to be inspected and the optical system inside the device (for example, the lens surface of the objective lens system), and removes the light from the fundus Er. It leads to the independent optical path of the light receiving optical system 20.

The light receiving optical system 20 of this embodiment has a lens 21, a light limiting unit 23, and a light separating unit (light separation unit) 30 in the reflected optical path of the perforated mirror 13. Further, lenses 24, 26, 28 are provided between the light separation unit 30 and the light receiving elements 25, 27, 29.

The light limiting unit 23 is arranged at a fundus conjugate position on the light receiving light path. As shown in FIG. 1, the light limiting unit 23 regulates a region through which the return light guided to the light receiving element passes (hereinafter, referred to as a passing region).

As shown in FIG. 1, the light limiting unit 23 is a rotating disk in which a plurality of openings having different sizes are formed as confocal openings. As an example, four openings 23a to 23d are formed. Each aperture regulates the area through which the return light passes. The center of rotation of the light limiting unit 23 is offset with respect to the optical axis L2 (reference optical axis in the independent optical path of the light receiving optical system 20). 23a to 23d are formed at the passing positions of the optical axis L2. By rotating the light limiting unit 23 by the motor 32, one of the openings 23a to 23d is selectively arranged on the optical axis L2. A part of the return light that has passed through the opening on the optical axis L2 is guided to the light receiving elements 25, 27, 29, and the other part is shielded by the rotating disk. In this embodiment, the size of the passing region is switched by switching the openings 23a to 23d arranged on the optical axis L2. In this embodiment, this adjusts the illumination depth.

In this embodiment, the openings 23a and 23b are provided as confocal openings in the case of the first angle of view, and the openings 23c and 23d are provided as confocal openings in the case of the second angle of view.

The opening 23a is used as a passage region of the first size of this embodiment. In this embodiment, it is used when taking a fundus image in the case of the first angle of view. Further, the opening 23b is smaller than the opening 23a. In this embodiment, the opening 23b is used as a second size passage area. That is, it is used when adjusting the focus in the case of the first angle of view.

Further, the opening 23d is used as a passing region of the third size. That is, it is used when adjusting the focus in the case of the second angle of view. The opening 23c is used when taking a fundus image in the case of the second angle of view.

The light separation unit 30 separates the light from the fundus Er. In this embodiment, the light from the fundus Er is wavelength-selectively separated by the light separation unit 30. Further, the optical separation unit 30 may also serve as an optical branching unit that branches the optical path of the light receiving optical system 20. For example, as shown in FIG. 1, the optical separation unit 30 may include two dichroic mirrors (dichroic filters) 31 and 32 having different optical separation characteristics (wavelength separation characteristics). The optical path of the light receiving optical system 20 is branched into three by two dichroic mirrors 31 and 32. Further, one of the light receiving elements 25, 27, and 29 is arranged at the end of each branch optical path.

For example, the light separation unit 30 separates the wavelengths of light from the fundus Er, and causes the three light receiving elements 25, 27, and 29 to receive light in different wavelength ranges. For example, the light receiving elements 25, 27, and 29 may receive light of three colors of blue, green, and red one by one. In this case, a color image may be acquired from the light receiving results of the light receiving elements 25, 27, and 29. Further, the light separation unit 30 may cause any light receiving element to receive the fundus reflected light in the infrared region. An infrared image may be acquired based on the signal from the light receiving element.

Here, the spectral characteristics of the light separation unit 30 will be described as an example. In the embodiment, the dichroic mirror 31 reflects at least red light and transmits light in other wavelength ranges. That is, the fundus reflected light with respect to the red illumination light is received by the light receiving element 25.

Further, the dichroic mirror 32 reflects at least green light and transmits light in other wavelength ranges. In the light receiving element 29 placed in the reflected light path of the dichroic mirror 32, the fundus reflected light with respect to the green illumination light is received by the light receiving element 27.

Further, the light receiving element 29 placed in the transmitted optical path of the dichroic mirror 32 receives blue light and infrared light. Therefore, the fundus reflected light with respect to the blue illumination light is received by the light receiving element 29. Further, the fundus reflected light with respect to the infrared light emitted from the light emitting unit 11 is received by the light receiving element 29.

<Angle of view switching unit>
Next, with reference to FIG. 2, the optical configuration when the shooting angle of view is the second angle of view, which is a wider angle of view, will be shown. In this embodiment, the lens attachment 3 is arranged between the objective optical unit 17 and the eye E to be inspected to form the objective optical unit 18 for taking a picture at the second angle of view. The lens attachment 3 of this embodiment has at least one lens. The shooting angle of view of the objective optical unit 18 is the second angle of view.

<Anterior segment observation optical system and alignment index projection optical system>
Further, the ophthalmologic imaging apparatus may have either an anterior ocular segment observation optical system or an alignment index projection optical system (both are not shown). The anterior segment observation optical system is used to acquire an anterior segment observation image based on a frontal image of the anterior segment. The alignment index projection optical system projects an alignment index, which is a reference for alignment adjustment, onto the cornea of the eye to be inspected.

<Control system>
Next, the control system of the present device 1 will be described with reference to FIG. In the present device 1, each unit is controlled by the control unit 70. The control unit 70 is a processing device (processor) having an electronic circuit that performs control processing of each part of the device 1 and arithmetic processing. The control unit 70 is realized by a CPU (Central Processing Unit), a memory, or the like. The control unit 70 is electrically connected to the storage unit 71 via a bus or the like. Further, the control unit 70 is electrically connected to each unit such as the light emitting unit 11, the light receiving elements 25, 27, 29, the scanning unit 16, the motor 23e, the actuator 40a, the input interface 75, and the monitor 80.

Various control programs, fixed data, and the like are stored in the storage unit 71. In this embodiment, a shooting control program or the like, which will be described later, is stored in the storage unit 71. Further, temporary data or the like may be stored in the storage unit 71. The image obtained by the present device 1 may be stored in the storage unit 71. However, the present invention is not limited to this, and the image obtained by the present device 1 may be stored in an external storage device (for example, a storage device connected to the control unit 70 via LAN and WAN).

The control unit 70 forms a fundus image based on the light receiving signals output from the light receiving elements 25, 27, and 29, for example. More specifically, the control unit 70 forms a fundus image in synchronization with the optical scanning by the scanning unit 16. For example, the control unit 70 takes at least one frame (in other words, one) of the fundus image (light receiving element) each time the optical scanner 16B for sub-scanning reciprocates n times (n is an integer of 1 or more). Form (every time). In the following, unless otherwise specified, for convenience, one frame of fundus image is formed for each round trip of the optical scanner 16B for sub-scanning. In this embodiment, since the three light receiving elements 25, 27, 29 are provided, the control unit 70 scans up to three types of images based on the signals from the respective light receiving elements 25, 27, 29 for sub-scanning. It is generated every time the optical scanner 16B of the above makes one round trip.

The control unit 70 may display the fundus images of a plurality of frames sequentially formed based on the operation of the device as described above on the monitor 80 as observation images in chronological order. The observation image is a moving image consisting of a fundus image acquired in substantially real time.

Further, the control unit 70 captures (captures) the fundus image as a captured image (captured image) based on the capture trigger. The captured image is stored in the storage medium. The storage medium in which the captured image is stored may be a non-volatile storage medium (for example, a hard disk, a flash memory, etc.).

The input interface 75 is an operation unit that accepts the operation of the examiner. For example, a touch panel, a mouse, a keyboard, and the like may be used as the input interface 75.

<Operation explanation>
Next, the shooting operation of the present device 1 will be described with reference to the flowchart of FIG. 7.

The lens attachment 3 is attached to and detached from the device 1 in advance, and the shooting angle of view of the device 1 is set (S1). The detached state of the lens attachment 3 may be manually input to the apparatus 1 by the examiner. Further, a sensor for detecting the attached / detached state of the lens attachment 3 may be provided in the present device 1, and a detection signal from the sensor may be input to the present device 1.

Next, the device is aligned with respect to the eye E to be inspected (S2). At the time of alignment, the examiner fixes the subject's face to the face support unit (not shown) of the apparatus 1. Further, the eye E to be inspected is fixed by the fixation target projection unit (not shown) of the present device 1. Further, the anterior segment observation optical system (not shown) may be controlled to generate and display an anterior segment observation image. Further, the control unit 70 may project the alignment index onto the cornea from the alignment index projection optical system (not shown). As a result, the alignment index image is superimposed on the anterior segment observation image. The positional relationship of the optical system (irradiation optical system 10 and light receiving optical system 20) with respect to the eye to be inspected is adjusted based on the anterior segment observation image and the alignment index image. The alignment may be manual alignment or automatic alignment. Alignment adjustment is completed by moving the optical system to a positional relationship (alignment allowable range) in which a fundus image can be taken.

After the optical system is moved to the alignment allowable range, the control unit 70 starts acquiring and displaying the fundus observation image (S3).

Next, the control unit 70 arranges an aperture having a larger size among the two openings corresponding to the shooting angle of view on the optical axis L2 (S4). That is, when the shooting angle of view is the first angle of view, the opening 23a is driven, and when the shooting angle of view is the second angle of view, the opening 23c is driven on the optical axis L2.

In this embodiment, the image brightness optimization control is executed with a larger size passing region set on the optical axis L2 (S5). At least one of the amount of light, the exposure time, and the gain is adjusted so that the histogram of the observation image acquired at any time approaches a predetermined target histogram. The target histogram may be defined by a target value, and for example, the width of the histogram (variance, full width at half maximum, standard deviation, etc.) may be predetermined as the target value. Although the details will be described later, in this embodiment, since the captured image is captured with the size of the passing region set to the first size, the same size of the passing region is also used in the optimization control of the image brightness. By performing this, a fundus image in which the image brightness is appropriately adjusted is taken as a captured image.

After adjusting the image brightness, the observation portion setting process is executed (S6). In this embodiment, the control unit 70 displays a grid that divides the observation image into a plurality of regions on the observation image (see FIG. 8). The examiner selects one of the plurality of areas divided by the grid via the input interface 75 (setting operation in this embodiment). The control unit 70 sets a site included in the selected region as an observation site. In the example of FIG. 8, the grid is divided into grids, but the present invention is not limited to this. For example, it may be divided in other division modes such as concentric circles and spider webs. Further, for example, by designating an arbitrary point on the observation image, a predetermined range centered on that point may be set as the observation site.

Next, the control unit 70 arranges an aperture having a smaller size among the two openings corresponding to the shooting angle of view on the optical axis L2 (S7). Here, when the shooting angle of view is the first angle of view, the opening 23b is driven, and when the shooting angle of view is the second angle of view, the opening 23d is driven on the optical axis L2. ..

After that, the control unit 70 executes the focus control process (S8). In the focus control process, the lens 14 is moved in one direction from the initial position in a predetermined adjustable range by a predetermined step (for example, 0.25D steps in the case of the first angle of view and 1 in the case of the second angle of view). (0.0D steps at a time) Move. In addition, each time the movement of a predetermined step is performed, the evaluation value at the observation site set on the observation image is obtained, and the focus position is adjusted to the position where the evaluation value peaks. For the evaluation value, information regarding the differential histogram at the observation site in the observation image may be used. For more details, refer to, for example, Japanese Patent Application Laid-Open No. 2013-188316 by the applicant.

In this embodiment, since the focus adjustment control (S8) is performed after the image brightness optimization control (S5) is completed, the image formation state can be better detected in the focus adjustment control (S8).

In this embodiment, the focus adjustment is performed based on the observation image acquired in the state where the passing region having a smaller size is set on the optical axis L2. By setting the size of the passing area to a smaller size (that is, by making it narrower), the illumination depth becomes shallower than when shooting, which will be described later. As a result, the focus is easily adjusted so that the observation site can be observed well. Further, even if the observation site is undulating with respect to the surroundings due to a disease or the like, the focus can be adjusted so that the observation site can be observed well.

After the focus adjustment, the control unit 70 returns the aperture arranged on the optical axis L2 to the larger aperture of the two apertures corresponding to the shooting angle of view (S9). Then, the fundus image is captured (S10). At the time of shooting, a brighter shot image is shot by setting the passing area to a larger size (that is, by expanding it). Further, as described above, as a result of the focus control process, the focus is appropriately adjusted with respect to the observed portion in the captured image, so that the observed portion can be easily observed in the captured image.

When the lens attachment 3 is attached (when the shooting angle of view is the second angle of view), the NA is smaller than when the lens attachment 3 is not attached (when the first angle of view is set), and the illumination is increased. The depth becomes deeper. On the other hand, in the present embodiment, when the lens attachment 3 is attached, the size of the passing region when adjusting the focus position is smaller than that when the lens attachment 3 is not attached, so that the illumination depth becomes deeper. Is suppressed. As a result, even when the lens attachment 3 is attached, the focused portion on the fundus region can be easily confirmed well through the observation image and the captured image.

10 Irradiation optical system 11 Light emission unit Irradiation optical system 23 Light limiting unit 40 Focus adjustment unit 70 Control unit

Claims (6)

A light emitting part that emits observation light and shooting light,
An irradiation optical system that irradiates the fundus of the eye to be inspected with light from the light emitting portion, and an irradiation optical system having a scanning means for scanning the light on the fundus.
A light-receiving optical system having a light-receiving element that outputs a light-receiving signal by receiving the return light of the light from the fundus.
A focus adjusting unit that adjusts the focus position in at least one of the irradiation optical system and the light receiving optical system,
A fundus photography device that includes a control means and captures a fundus image based on a light receiving signal from the light receiving element.
An illumination depth adjustment unit capable of switching the illumination depth in at least one of the irradiation optical system and the light receiving optical system between a first illumination depth and a second illumination depth shallower than the first illumination depth. , Further preparation,
The control means acquires an observation image as the fundus image based on the received signal of the return light by the observation light, and sets the second illumination depth when adjusting the focus position based on the observation image. At the same time, when a photographed image is photographed as the fundus image based on the received signal of the return light by the photographed light, the fundus photography device executes an illumination depth control process for setting the first illumination depth. The illumination depth adjusting unit has a light limiting unit that is arranged at a position conjugate with the fundus of the light receiving optical system and regulates a passing region through which the return light guided to the light receiving element passes.
The light limiting unit sets the size of the passing region as a first size corresponding to the first illumination depth and a second size corresponding to the second illumination depth, which is narrower than the first size. The fundus imaging device according to claim 1, which can be switched between. As the illumination depth adjusting unit, the beam diameter of the light emitted from the irradiation optical system to the eye to be inspected is a diameter larger than the first beam diameter corresponding to the first illumination depth and the first beam diameter. The fundus imaging apparatus according to claim 1 or 2, which is thick and has a beam diameter switching portion that can be switched between the second illumination depth and the corresponding second beam diameter. The control means sequentially acquires the observation image in a state where the illumination depth is set to the second illumination depth, and the focus adjustment unit is based on information on the imaging state detected from the observation image. Further execute the focus control process that drives
The fundus photography apparatus according to any one of claims 1 to 3, wherein the photographed image is photographed at a focus position set as a result of the focus control process. The control means further executes a setting process for setting a part of the imaging range as an observation site, and also executes the setting process.
The fundus photography apparatus according to claim 4, wherein in the focus control process, the focus adjustment unit is driven based on information on the imaging state at the observation site. The fundus photography device according to claim 5, wherein the control means receives a setting operation of the observation site in the setting process and sets the observation site based on the setting operation.